Design for the Environment Printed Wiring Board Project
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Design for the Environment Printed Wiring Board Project Presentation of the Surface Finishes Cleaner Technologies Substitutes Assessment (CTSA) Results Presented in coordination with the Chicagoland Circuit Association Elk Grove, IL November 29, 2000 Acknowledgments This seminar presents the results of the Surface Finishes Cleaner Technologies Substitutes Assessment (CTSA), written by Jack Geibig, Mary Swanson, and Rupy Sawhney of the University of Tennessee’s Center for Clean Products and Clean Technologies. Valuable contributions to the project were provided by the project’s Core Group members not already mentioned above, including: Kathy Hart, EPA Project Lead and Core Group Co-Chair; Holly Evans and Christopher Rhodes, formerly of IPC-Association Connecting Electronics Industries, Core Group Co-Chairs; Dipti Singh, EPA Technical Lead and Technical Workgroup Co-Chair; John Sharp, Teradyne Inc., Technical Workgroup CoChair; Michael Kerr, BHE Environmental Inc., Communication Workgroup Co-Chair; Gary Roper, Substrate Technologies Inc.; Greg Pitts, Microelectronics and Computer Technology Corporation; and Ted Smith, Silicon Valley Toxics Coalition. We would like to acknowledge Ron Iman (505/856-6500) of Southwest Technology Consultants and Terry Munson of Contamination Studies Laboratory (CSL) for their work in planning and analyzing the results of the performance demonstration. Acknowledgment is also given to the suppliers of the technologies evaluated in the CTSA, including Alpha Metals; Dexter Electronic Materials; Electrochemicals, Inc.; Florida CirTech; MacDermid, Inc.; and Technic, Inc., who, in addition to supplying the various technologies, contributed significant technical input for the performance demonstration. Recognition is also given to ADI/Isola, who supplied the materials for the performance demonstration, to Network Circuits, for volunteering their services to build and test the boards, and to the sixteen test facilities. We would also like to express appreciation to Andrea Blaschka, Susan Dillman, Conrad Flessner, Franklyn Hall, Susan Krueger, Fred Metz, and Jerry Smrchek, as members of the EPA Risk Management Workgroup, who provided valuable expertise and input during the development of the CTSA. Many thanks also to the industry representatives and other interested parties who participated in the Technical Workgroup, for their voluntary commitments to this project. 2 Design for the Environment Printed Wiring Board Project Partnerships for a Cleaner Future 6 DfE Vision Business decision-makers integrate environmental concerns into cost and performance criteria Cost Performance Decision Environment 7 Project History Began working with the PWB industry in 1993 MCC study assessed the life cycle of a computer workstation Material and chemical use Hazardous waste Water use Energy use Conducted assessment of making holes conductive technologies as first project 8 Project Partners IPC PWB Manufacturers and Suppliers EPA MCC Public Interest Groups Partners for Change University of Tennessee 9 DfE Workgroups Core Technical Implementation Occupational exposure Environmental releases Performance Cost Information products Seminars Implementation guides Web site Community outreach Communication P2 case studies Presentations Trade show booth Trade journals 10 Information Products Implementing Cleaner PWB Technologies: Surface Finishes PWB Cleaner Technologies Substitutes Assessment: Making Holes Conductive Implementing Cleaner Technologies in the PWB Industry: Making Holes Conductive PWB Pollution Prevention and Control: Analysis of Updated Survey Results PWB Industry and Use Cluster Profile Federal Environmental Regulations Affecting the Electronics Industry (1995) 9 Pollution Prevention Case Studies Project Fact Sheets and Journal Articles These reports can be ordered through EPA’s Pollution Prevention Information Clearinghouse, at 202/260-1023, or viewed on the DfE website at www.epa.gov/dfe 11 EPA Goals and Objectives Effect change in PWB industry that results in pollution prevention Leverage industry resources Foster open and active participation in addressing environmental issues Demonstrate that pollution prevention makes economic sense 12 Design for the Environment Printed Wiring Board Project Industry Perspectives 13 Industry Goals and Objectives Identify and implement P2 technologies that perform competitively and are cost-effective Make informed decisions that include consideration of human health and environmental risk Develop useful information for PWB industry within a short time frame Help ensure credibility and validity of project data 14 Benefits to Industry Research conducted by neutral parties Risk assessment expertise Full-time project leadership Change from confrontational to partnering relationship 15 Benefits to Industry Proactive management of environmental affairs and increased competitiveness: Reduce health and environmental risk Reduce material and compliance costs Reduce liabilities Leverages limited resources of small to medium-sized businesses 16 Advantages of DfE Approach Cooperative approach to environmental problem-solving Focused project that produces useful data and facilitates pollution prevention EPA funding, which includes: Development and analysis of data Demonstration of alternative technologies Communication of cost-effective P2 information 17 Design for the Environment Printed Wiring Board Project Community Perspectives 18 Community Goals and Objectives Encourage the development of cleaner and safer technologies that provide better protection for workers and the community Develop a model for cleaner technology assessment, development, and implementation Learn more about the PWB industry and disseminate that information Help to equip community residents and workers to become more informed stakeholders so they can be more effective participants in joint projects Ensure that the DfE process is credible to communities and workers and that it is conducted in a comprehensive, fair, and equitable manner 19 Potential Benefits to the Community and Workers The partnership and combined expertise between government, industry, academia, and NGOs can lead to an improved process, product, and data The results of the DfE process, if conducted properly and implemented successfully, can lead to improved public and occupational health The DfE process exposes all participants to each other’s interests, needs, and contrasts, and helps to overcome stereotypes 20 Potential Benefits to the Community and Workers The DfE process can help support environmental advocates within the industry With the full support of all stakeholders, implementation can be more effective The DfE process recognizes that there are mutual benefits in the relationship between industry, government, universities, communities, and workers to encourage a sustainable economy and corporate accountability 21 Design for the Environment Printed Wiring Board Project Introduction to PWB Manufacturing and CTSA Methodology 22 CTSA Process Use Cluster Profile Process identification Flow chart showing "steps" Description Phase Chemicals, materials, technologies Commonly accepted alternatives High environmental impact areas Use Cluster Risk and release Alternate chemicals, materials, and processes Selected step Scoring Cleaner Technologies Substitutes Assessment (CTSA) Cost and performance Comparative risks Environmental release Resource conservation Energy impacts Informed decision by PWB Manufacturers 23 Cluster Selection Evaluation showed essentially equal and medium risk Making holes conductive was subject of first DfE/IPC project Surface finishing process selected Technology alternatives were available Timely 24 Use Cluster Selected Surface Finishing Use Cluster Circuit Design/ Data Acquisition Inner Layer Image Transfer Laminate Inner Layers Drill Holes Clean Holes Make Holes Conductive Outer Layer Image Transfer Hot Air Solder Leveling OSP Electroless Nickel/ Immersion Gold Immersion Silver Immersion Tin Electroless Nickel/Palladium/ Immersion Gold Surface Finish Final Fabrication 25 CTSA Approach Industry and use cluster profiles Pollution prevention survey Regulations affecting the electronics industry Workplace practices survey Performance demonstration Risk assessments Cost model and analysis Implementation guide Pollution prevention case studies 26 CTSA Methodology WP Survey P2 Survey Industry Profiles Regs Perf Demo Risk Assessments 27 Surface Finish Mechanisms Electroless- metal plating process driven by oxidation-reduction reaction without the use of an external power source Immersion- metal plating driven by a chemical replacement reaction without the use of an external power source auto-catalytic reaction multiple layers self-limiting reaction monomolecular layer Coating- application of a protective layer to the board by physical contact of the chemistry to the board coating can be thin or thick 28 HASL Profile Solder surface finish has been reliable standard for many years Selection of flux is critical to performance Lack of planarity and presence of lead has been driving development of alternatives Compatible with SMT and through-hole Operated in either conveyorized or nonconveyorized mode 29 Electroless Nickel/Immersion Gold Profile Thin layer of gold prevents the highly active nickel layer from oxidizing, thus protecting the solderability of the finish Compatible with SMT, flip chip, and BGA technologies Aluminum wire-bondable Operated in either conveyorized or nonconveyorized mode 30 Electroless Nickel/Electroless Palladium/Immersion Gold Profile Similar to Nickel/Gold, but with a palladium layer that lends added strength to the surface finish for component attachment Compatible with SMT, flip chip, and BGA technologies Both gold and aluminum wire-bondable Operated in either conveyorized or nonconveyorized mode 31 OSP Profile OSP applies a planar anti-oxidation coating to copper surface to preserve solderability benzotriazoles and imidazoles (thin) substituted benzimidazole (thick) Compatible with SMT, flip chip, and BGA technologies Operated in either conveyorized or nonconveyorized mode 32 Immersion Silver Profile Organic inhibitor forms a hydrophobic layer on the silver surface, which protects solderability Compatible with SMT, flip chip, and BGA technologies Gold and aluminum wire-bondable Operated exclusively in horizontal, conveyorized mode 33 Immersion Tin Profile Immersion tin process utilizes a codeposited organo-metallic compound prevents formation of a Sn-Cu intermetallic layer inhibits dendritic growth Compatible with SMT, flip chip, and BGA technologies Typically operated in horizontal, conveyorized equipment 34 Typical Facility Goal is to perform comparative, not absolute, evaluations Data aggregated across alternatives to determine basic parameters, for example: average throughput operating days per year Calculations were based on combination of average and high-end values from the Workplace Practices Survey 35 Typical Facility Characteristics PWB operation occupies 45,400 square feet Facility manufactures 416,000 ssf of PWBs Surface finish processes operates in 3,670 square foot room operates 307 days per year temperature is 75º F (average) ventilation air flow rate of 4,650 cu.ft./min. 36 Typical Facility - Types of Employees in SF Area Line operators Laboratory technicians Maintenance workers Supervisory personnel Wastewater treatment operators Others (e.g., quality inspectors process control specialist) 37 Typical Facility - SF Area Employee Data Average employee duration in process area - 8 hour Employee work days per year - 250 Operation picked as first shift only Conveyorized process exposure is much lower than non-conveyorized 38 Surface Finish Automation Process Configurations Evaluated in CTSA Surface Finish Process Non-Conveyorized HASL Nickel/Gold Nickel/Palladium/Gold OSP Silver Tin Conveyorized 39 Typical Processes for Alternatives - Examples HASL Silver Nickel/Gold Cleaner Microetch Cleaner Cleaner Water Rinse Dryer Water Rinse x2 Water Rinse Water Rinse Microetch Flux Solder Catalyst Water Rinse Water Rinse Acid Dip Nickel Water Rinse x2 Water Rinse x2 Gold HP Rinse Microetch Air Knife Water Rinse Water Rinse Predip Silver Water Rinse Dryer 40 Design for the Environment Printed Wiring Board Project Cost Analysis of Surface Finish Technologies 41 Problem Framework B2 A2 Sites B1 A1 G2 BN AN G1 GN Database A B C D E F G Model Facilities AC ANC $/ssf $/ssf Generic Technologies DNC GC $/ssf $/ssf 42 Project Tasks Develop costs for model facilities that utilize the generic technologies Develop cost estimates for the application of the surface finish for: 260,000 ssf of PWBs (avg. throughput for HASL processes) 60,000 ssf of PWBs (avg. throughput for nonHASL processes) 43 Cost Analysis Dimensions Model Facilities AC ANC .... DNC .... G1 G2 GC $/260,000 ssf A1 A2 . . . . AN . . . . GN Actual Facilities 44 Cost Analysis Objectives Fundamentally sound analysis of model facilities Flexible system to calculate actual facility cost Highlight environmental costs 45 Cost Analysis Goals Use the process to estimate comparative costs for model facilities Provide insight into costs for actual facilities activity-based costs sensitivity analysis 46 Hybrid Cost Formulation Framework Surface Finish Processes Development of Cost Categories Development of Traditional Costs Formulation Development of Simulation Model Development of the Bill of Activities (BOA) Cost Analysis Sensitivity Analysis 47 Process Model Key Assumptions Process operated at 6.8 hours per day Remaining 1.2 hours taken up by: routine maintenance start up and shut down procedures PWB panels are assumed to be available without delay when feeding surface finish process Simultaneous bath changeouts are considered to occur simultaneously with regard to downtime 48 Non-Conveyorized Process Key Assumptions Production based on rate limiting step and overall cycle time One rack is allowed in a bath at one time A rack consists of 84.4 ssf of PWB Labor is calculated using 1.1 employees to reflect more labor intensive process Production system is cleared at the end of a shift or before a bath is replaced 49 Conveyorized Process Key Assumptions Production based on average cycle time and conveyor speed A panel consumes 18 inches of the conveyor Process is operated by one line operator with regard to labor Production system is cleared at the end of a shift or before a bath is replaced 50 Cost Categories Cost Category Cost Components Capital Cost Primary Equipment Installation Facility Material Cost Chemical(s) Utility Cost Water Electricity Gas Licensing/Permit Cost Wastewater Discharge Production Transportation of Material Labor for Normal Production Maintenance Cost Tank Cleanup Bath Setup Sampling and Testing Filter Replacement Total Cost 51 Simulation Model for the Conveyorized Immersion Tin Process Generic Immersion Tin S CANNER S CANNER S CANNER S CANNER S CANNER CLEANER RINSE x2 MICROETCH RINSE x2 PREDIP SCANNER S CANNER RINSE x1 IMMERSION TIN DRYER RINSE x2 S CANNER S CANNER 0 52 Simulation Output for Non-Conveyorized Nickel/Gold Process Chemical Bath Frequency Average Time/ Replacement (min) Total Time (min) Cleaner 7 116 812 Microetch 9 116 1,044 Catalyst 6 116 696 Acid Dip 4 116 464 Electroless Nickel 40 116 4,640 Immersion Gold 6 116 696 Total 72 8,352 53 Surface Finish Process Operating Times Data based on 260k ssf PWB production Surface Finish Process Simulation Run Time (days) Simulation Downtime (days) Operating Time (days) HASL [N] 43.7 5.7 38.0 HASL [C] 21.8 2.3 19.5 Nickel/Gold 212 18.8 193.4 Nickel/Palladium/Gold [N] 280 27.9 252.1 OSP [N] 35.2 6.2 29 OSP [C] 16.1 2.5 13.6 Silver [C] 64.2 3.4 60.8 Tin [N] 75.2 4.6 70.6 Tin [C] 107 2.5 104.5 54 BOA for Transportation of Chemicals Activities Resources Time (min) Transportation of chemicals to bath Labor A. Paperwork and Maintenance Cost Materials Forklift $/transpor t $10.24/hr i. Request for Chemicals 2 $0.34 $0.10 $0.00 $0.44 ii. Updating Inventory Logs 1 $0.17 $0.05 $0.00 $0.22 iii. Safety and environmental 2 $0.34 $0.10 $0.00 $0.44 i. Move forklift to parking area 2 $0.34 $0.00 $0.12 $0.46 ii. Prepare forklift to move chemicals 5 $0.85 $0.25 $0.30 $1.15 iii. Move to line container storage area 2 $0.34 $0.00 $0.12 $0.46 iv. Prepare forklift to move line container 3 $0.51 $0.00 $0.18 $0.69 v. Move forklift to chemical storage area 2 $0.34 $0.00 $0.12 $0.46 B. Move forklift to chemical storage area BOA for Transportation of Chemicals Activities Labor Transportation of chemicals to bath C. Locate chemicals in storage area i. Move forklift to appropriate area(s) Resources Time (min) Cost Materials Forklift $/transpo rt $10.24/hr 1 $0.17 $0.00 $0.06 $0.23 ii. Move chemical containers from storage to staging 2 $0.34 $0.00 $0.12 $0.46 iii. Move chemical containers from staging to storage 2 $0.34 $0.00 $0.12 $0.46 1 $0.17 $0.05 $0.00 $0.22 ii. Utilize appropriate tools to appropriate containers 3 $0.51 $0.05 $0.00 $0.56 iii. Place appropriated chemicals in line container(s) 3 $0.51 $0.00 $0.00 $0.51 1.5 $0.09 $0.00 $0.00 $0.09 1 $0.17 $0.00 $0.06 $0.23 D. Preparation of chemicals for transfer i. Open chemical containers iv. Close chemical container(s) v. Place line container(s) on forklift BOA for Transportation of Chemicals Activities Time (min) Transportation of chemicals to bath Resources Cost Labor Materials Forklift $/transport E. Transport chemicals to line i. Move forklift to line 2 $0.34 $0.00 $0.12 $0.46 ii. Unload line container(s) at line 1 $0.17 $0.00 $0.06 $0.23 Cost Composition for Non-Conveyorized Nickel/Gold Process Maintenance Cost to Produce 260,000 ssf Tank Cleanup Number of tank cleanups Simulation Model (72) X Bath Setup Cost/tank setup annual number of samples BOA ($67) Exposure Assessment (1260) X $4,824 $1,087 Filter Replacement Sampling X utilization ratio X Simulation Model (0.76) $3,530 X cost per sample X BOA ($3.70) $1,580 Cost Summary: Non-Conveyorized Nickel/Gold Process Cost Category Cost Component Cost ($) Capital Costs Primary Equipment and Installation Facility $7,260 Material Costs Chemical Products $108,600 Utility Costs Water Electricity Natural Gas $1,180 $2,360 $0 Wastewater Costs Wastewater Discharge $2,050 Production Costs Transportation of Materials Labor $668 $19,100 Maintenance Costs Tank Cleanup Bath Setup Sampling and Testing Filter Replacement $4,830 $1,090 $3,530 $1,580 Total Process Cost $2,930 $156,000 Cost based on 260k ssf PWB production 59 Cost Comparison of PWB Surface Finish Processes Total costs based on 260k ssf of PWB production Surface Finish Process Total Cost ($) Cost ($/ssf) HASL [N] $94,200 $0.36 HASL [C] $92,400 $0.35 Nickel/Gold [N] $156,000 $0.60 Nickel/Palladium/Gold [N] $399,000 $1.54 OSP [N] $28,700 $0.11 OSP [C] $26,300 $0.10 Silver [C] $73,800 $0.28 Tin [N] $46,900 $0.18 Tin [C] $64,700 $0.25 60 Cost Comparison of PWB Surface Finish Processes Total costs based on 60k ssf of PWB production Surface Finish Process Total Cost ($) Cost ($/ssf) HASL [N] $20,000 $0.33 HASL [C] $19,800 $0.33 Nickel/Gold [N] $36,300 $0.61 Nickel/Palladium/Gold [N] $92,200 $1.54 OSP [N] $6,800 $0.11 OSP [C] $5,800 $0.10 Silver [C] $16,700 $0.28 Tin [N] $10,600 $0.18 Tin [C] $13,400 $0.22 Note: Costs are preliminary (not final) 61 Cost Comparison of PWB Surface Finish Processes Total costs based on 260k ssf of PWB production Process 260K ($/ssf) +/($/ssf) % Change from baseline HASL [N] $0.36 * * HASL [C] $0.35 -$0.01 -3% Nickel/Gold [N] $0.60 +$0.24 +67% Nickel/Palladium/Gold [N] $1.54 +$1.18 +327% OSP [N] $0.11 -$0.25 -69% OSP [C] $0.10 -$0.26 -72% Silver [N] $0.28 -$0.08 -22% Tin [N] $0.18 -$0.18 -50% Tin [C] $0.25 -$0.11 -31% 62 Design for the Environment Printed Wiring Board Project Comparative Risk of Surface Finish Technologies 63 Presentation Overview Purpose of SF risk characterization Risk characterization methods Assumptions and Uncertainties Risk characterization results Process Safety Assessment 64 Purpose of SF Risk Characterization Perform screening-level risk characterization to: compare risks of exposure to chemicals in baseline and alternative SF processes identify areas of potential concern for SF processes Present information about variability, uncertainty, and key assumptions 65 CTSA Risk Characterization Process Workplace Practices Source Release Assessment Human Health Hazards Exposure Assessment Risk Characterization Environmental Hazards 66 Exposure Assessment Occupational exposure to: Ambient population exposure to: line operators laboratory technicians others in process area humans living near a facility aquatic organisms Model facility approach 260,000 ssf production 67 Pathways for Worker Exposure Chemical Source Release Medium Evaporation Aerosol generation Chemical Bath Exposure Medium Air Inhalation Air Direct Contact Equipment Cleaning Exposure Route Dermal Contact 68 Occupational Exposure Methodology Air concentrations based on: supplier bath chemistry data workplace practices data (bath temperature, etc.) air emission models Dermal concentrations based on supplier bath chemistry data Exposure time based on Workplace Practices Survey data Exposure frequency based on Workplace Practices Survey data, supplier information, and modeled time to finish set amount of boards (260,000 ssf) Default assumptions for inhalation rate, body weight, exposure averaging times 69 Occupational Exposure: Non-Conveyorized Processes Baths are not enclosed Inhalation exposure to vapors from all baths and to aerosols from air-sparged baths line operator is exposed 8 hours/day exposure to others is proportional to time spent in process area no vapor controls on baths Dermal exposure through line operation and bath maintenance, 8 hours/day 70 Occupational Exposure: Conveyorized Processes Equipment is enclosed and typically vented to the outside Inhalation exposure to workers assumed negligible Dermal exposure through bath and filter replacement, bath sampling, and conveyor equipment cleaning Dermal exposure contact time varies by process and by bath 71 Population Exposure Inhalation exposure to humans living near a facility No air pollution controls assumed Outdoor air concentrations modeled using an EPA air dispersion model, and estimated air emission rates from process baths 72 Key Assumptions in the Exposure Assessment Workers do not wear gloves; otherwise dermal exposure and risk would be negligible Non-conveyorized lines are fully manual Steady state air concentrations in process area Form/concentration of chemicals in bath are constant over time Air turnover rate = 1.56/hour (480 ft3/min. general ventilation rate, 18,200 ft3 room size) 73 Uncertainties in the Exposure Assessment Similarity of model facility to any actual facility (variability among facilities) Chemical concentrations in baths variation among products variation with time Limitations of workplace practices data (variability in workplace practices) Uncertainties in models and assumptions (modeling estimates vs. monitoring data) 74 Exposure Risk Descriptors High-end : Accounts for persons at the upper end of exposure distribution (capture variability) Central tendency: Average or median estimates of exposure values 90% of actual values would be less avoid estimates beyond true distribution What if : Based on hypothetical conditions or limited data where the distribution is unknown does not describe how likely estimated level of exposure might be 75 Descriptors for the SF Risk Characterization Based on combination of average, high-end, and “what-if” values Aim was for overall high-end risk characterization Average: body weight, breathing rate, bath concentrations High-end: duration of worker activities What if: use of gloves, days/yr Result is “what if” risk characterization 76 Uncertainties in the Hazard Data Effects of chemical mixtures Using short-term, high dose animal studies to predict effects in humans Lack of measured toxicity data for some chemicals Variability in characteristics of exposed population (some people are more sensitive than others) 77 Risk Characterization Overview Cancer risks to humans Other chronic health risks (humans) Aquatic risks Results compared to levels of concern 78 Methods to Calculate Risk Cancer risk expressed as probability result is upper bound lifetime excess cancer risk weight of evidence also considered Other chronic health risks expressed as ratio to reference value hazard quotient (better quality data), or margin of exposure qualitative (H, M, L) if no toxicity value was available 79 Carcinogenic WOE Classifications of SF Chemicals Classification Chemical Alternative Human carcinogen or probable human carcinogen1 Inorganic metallic salt A Nickel/Gold IARC Group I -human carcinogen Sulfuric acid All processes EPA Group B2 -probable human carcinogen Lead HASL IARC Group B2 -possible human carcinogen Lead HASL Thiourea Immersion Tin Possible human carcinogen1 Urea Compound B Nickel/Gold Nickel/palladium/gold 1Specific classification not presented to protect confidential ingredient identity. 80 Cancer Risk Results Estimated for inhalation exposure to inorganic metallic salt A in the Nickel/gold process Occupational inhalation risks for line operators non-conveyorized: “high end” estimate ranges from near zero to 2 x 10-7 (1 in 5 million) Estimated ambient population risks are low, with upper bound maximum of 1 in 50 billion 81 Chronic Health Risk Results Low concerns for inhalation risks to nearby residents for all technologies Occupational inhalation risks assumed negligible for conveyorized processes concerns for some chemicals in four non-conveyorized processes Occupational dermal exposure risks concerns for some chemicals in five nonconveyorized and two conveyorized processes 82 SF Chemicals of Concern for Potential Inhalation Risks Process (NC, 260,000 ssf) a Chemical HASL Alkyldiol Ethylene Glycol Nickel/Gold Nickel/Palladium /Gold Immersion Tin Hydrochloric Acid Hydrogen Peroxide Nickel Sulfate Phosphoric Acid Propionic Acid OSP a: Non-conveyorized Immersion Silver process not evaluated Line operator risk results above concern levels (noncancer health effects) 83 SF Chemicals of Concern for Potential Dermal Risks Process a (260,000 ssf) Chemical HASL HASL [C] [NC] Nickel/ gold/ (NC) Nickel/ Palladium/ gold (NC) Immersion OSP OSP [NC] [C] Tin (NC) Ammonia Compound A Ammonium chloride Ammonium hydroxide Copper ion Copper salt C Copper sulfate pentahydrate Hydrogen peroxide Inorganic metallic salt B Lead Nickel sulfate Urea Compound C a: No risk results were above concern levels for the Immersion Silver (conveyorized) process Line operator risk results above concern levels (noncancer health effects) Line operator and laboratory technician risk results above concern levels (noncancer health effects) C = conveyorized (horizontal) process configuration NC = non-conveyorized (vertical) process configuration 84 Aquatic Risk Chemicals ranked for aquatic toxicity using established EPA criteria Concern concentration (CC) = acute or chronic toxicity value divided by uncertainty factor Inorganic metallic salt A, silver nitrate, and silver salt have lowest CC 85 Aquatic Hazard and Risk CC compared to estimated surface water concentration (CSW ) Drag-out study used to estimate chemical loss through rinse water and surface water concentrations (assuming no treatment) Chemicals with CSW > CC evaluated further considering treatment efficiency Aquatic risk expressed as a ratio of estimated surface water concentration to CC 86 Drag-Out Study Develop a model that estimates the quantity and characteristics of drag-out Use the model to: identify critical factors influencing drag-out quantify chemical loss and subsequent mass loading of on-site treatment determine the effect of organic chemicals released through drag-out on surface waters Model was used to calculate a mass loading to the on-site treatment facility: inorganics assumed to be treated on-site to permit levels organics were considered treated in POTW 87 Non-metal Chemicals of Concern for Aquatic Risk Chemical HASL (NC) HASL (C) Alkylaryl imidazole X Alkylaryl sulfonate X 1,4-Butenediol X Hydrogen peroxide X X Potassium peroxymonosulfate X X Thiourea OSP (NC) OSP Immersion Immersion tin (C) silver (C) (NC) X X X X X Estimated surface water concentration > Concern Concentration (CC) after POTW treatment 88 Comparing Risks to Concern Levels Type of Risk Cancer Noncancer -RfD Other (N or L) Aquatic Risk Indicator E x SF Concern Level > 1 x 10 -6 E / RfD N or L / E Csw / CC >1 < 100 for N, < 1,000 for L >1 E: Exposure estimate N or L: NOAEL or LOAEL SF: Cancer slope factor Csw: Surface water concentration RfD: Reference Dose CC: Aquatic concern concentration 89 Risk Comparison 35 No. chemicals 30 25 dermal gaps 20 inhalation gaps 15 dermal concern 10 inhalation concern aquatic concern (C ) .T in m Im .T in m Im .S ilv er m Im (N (C C ) ) (C O SP (N O SP C (N d d/ G ol i/P N C ) ) (N d i/G ol N AS L H C (C ) C (N AS L H ) 0 ) pot. carcinogen ) 5 Process configuration 90 Risk Conclusions Chemicals in seven process configurations may pose noncancer chronic health risks inhalation concerns: HASL, Nickel/gold, Nickel/palladium/gold and OSP (all non-conveyorized) dermal exposure concerns: HASL (NC & C), Nickel gold (NC), Nickel palladium gold (NC), OSP (NC & C), and Immersion tin (NC) Cancer risk in Nickel gold process due to confidential ingredient (inorganic metallic salt A) less than 1 x 10-6 91 Conclusions, continued Overall, for health risks: risks are uncertain for lead in HASL (more monitoring data are needed) there are chemical risk results for human health above concern levels for all processes evaluated except Immersion silver and conveyorized immersion tin There are chemical risk results for aquatic life above concern levels for HASL, OSP, Immersion silver and Immersion tin 92 Process Safety Assessment Used Material Safety Data Sheets for chemical products Process Safety Concerns general OSHA requirements equipment safeguards Chemical Safety Concerns flammable (F), combustible (C) explosive (E), fire hazard (FH), Corrosive (CO), oxidizer (O), reactive (R), or unstable (U) acute and chronic occupational health hazards other chemical hazards 93 Chemical Safety Concerns: Summary 94 Chemical Safety Concerns Acute and chronic health hazards all alternatives listed both acute and chronic health hazards and sensitizers all listed irreversible eye damage Immersion silver and OSP were the only alternatives not containing a carcinogen Other Chemical Hazards most have chemical decomposition hazards chemical incompatibilities include acids, alkalis, oxidizers, metals, and reducing agents 95 Chemical Safety Concerns Other Chemical Hazards, continued some have incompatibilities between chemical products used on the same process line HASL, OSP, Immersion Silver, and Immersion Tin contain chemical(s) that are considered flammable, explosive, or a fire hazard all alternatives contain corrosive chemicals Immersion Tin was the only alternative not to contain chemical(s) that were considered to be unstable, an oxidizer, or have a sudden release of pressure 96 Design for the Environment Printed Wiring Board Project Resource Conservation and Energy Impacts 97 Objective Resource conservation relative use of natural resources (water, chemicals, energy, etc.) during the surface finishing process (HASL vs. alternatives) Energy conservation relative rate of energy consumption during the application of the surface finish by HASL and the alternatives 98 Resource Conservation Data Types Process specifications Physical process parameters Operating procedures 99 Water Consumption of Surface Finishing Processes # of Rinse Stages Rinse Water Consumed (gal/260,000 ssf) Water Consumption (gal/ssf) HASL [N] 3+1 HP 3.22 x 10 5 1.24 HASL [C] 3+1 HP 2.58 x 10 5 0.99 Nickel/Gold [N] 8 5.37 x 10 5 2.06 Nickel/Palladium/Gold [N] 14 9.39 x 10 5 3.61 OSP [N] 3 2.01 x 10 5 0.77 OSP [C] 3 1.37 x 10 5 0.53 Silver [C] 3 1.37 x 10 5 0.53 Tin [N] 7 4.69 x 10 5 1.81 Tin [C] 5 2.29 x 10 5 0.88 Surface Finish Process N = Non-Conveyorized, C = Conveyorized, HP = High pressure rinse 100 Water Consumption of Surface Finish Technologies Surface Finish Process Gal/ssf Change HASL [N] 1.24 --- HASL [C] 0.99 - 20% Nickel/Gold [N] 2.06 + 66% Nickel/Palladium/Gold [N] 3.61 + 191% OSP [N] 0.77 - 38% OSP [C] 0.53 - 57% Silver [C] 0.53 - 57% Tin [N] 1.81 + 46% Tin [C] 0.88 - 29% N = Non-Conveyorized, C = Conveyorized 101 Conclusions: Water Use Several surface finish processes consumed less water than the baseline HASL process reduction primarily due to the reduced number of rinse stages conveyorized processes typically use less water than non-conveyorized Magnitude of savings is facility-dependent examples: efficiency of previous process, differences between alternatives, facility practices 102 Process Chemicals Quantitative analysis of process chemicals was not possible due to the variability of: process-specific factors (e.g., bath concentration, composition, operating parameters) facility-specific factors (e.g., operating practices, bath replacement frequency) 103 Wastewater Treatment Chemicals Quantity of treatment chemicals consumed is dependent on: process-specific factors (e.g., type of process, water flow rate, volume of drag out) facility-specific factors (e.g., other mfg. processes, volume of wastewater, type of treatment system) Additional treatment steps or modifications may be desirable with certain finish processes (e.g., increased silver levels, thiourea, cyanide) 104 Energy Impacts Energy consumption during process operation Energy production environmental impacts 105 Energy-Consuming Equipment Type of Equipment Function Conveyor System Automate the movement of panels through the process. Panel Agitation Motor Agitate apparatus used to gently rock panel racks back and forth in the process baths. Not required for conveyorized processes. Fluid Pump Circulate bath fluid to facilitate uniform chemical contact with all surfaces of the PWB panels. Air Pump Compress air to be used by an air knife to blow residual bath chemisties or solder from the surface of the PWB. Air is also used to sparge select chemical baths in certain processes. Immersion Heater Raise and control temperature of a process bath to the optimal operating condition. Solder Pot Heats solder and maintains the molten solder at proper operating conditions. Gas Heater Heat PWB panels to promote drying of residual bath chemistries remaining on the panel surfaces. 106 Energy Usage Profiles Conv Process Type Agit. Motor Air Pump Fluid Pump Bath Heat Solder Pot Gas Dry Energy Usage (BTU/hr) HASL [N] * 1 2 3 1 1 1 219,800 HASL [C] 1 * 2 4 1 1 1 260,400 Nickel/Gold [N] * 1 1 3 4 * * 88,700 Nickel/Palladium/ Gold [N] * 1 1 3 6 * * 116,700 OSP [N] * 1 2 3 2 * 1 165,500 OSP [C] 1 * 2 3 2 * 1 203,100 Silver [C] 1 * * 4 2 * 1 180,200 Tin [N] * 1 * 4 2 * 1 142,700 Tin [C] 1 * * 3 2 * 1 177,100 107 Energy Consumption Process Operating Time (Hours) Total Energy Consumed (BTU/260,000 ssf) Energy Usage Rate (BTU/ssf) HASL [N] 258 5.67 x 10 77 218 HASL [C] 133 3.46 x 10 77 133 Nickel/Gold [N] 1310 1.16 x 10 88 447 Nickel/Palladium/Gold [N] 1710 2.00 x 10 88 768 OSP [N] 197 3.26x 10 77 125 OSP [C] 93 1.89 x 10 77 73 Silver [C] 414 7.46 x 10 77 287 Tin [N] 480 6.48 x 10 77 263 Tin [C] 710 1.36 x 10 88 522 Process Type N = Non-Conveyorized, C = Conveyorized 108 Comparison of Energy Consumption Surface Finish Process BTU/ssf Change HASL [N] 218 --- HASL [C] 133 - 39% Nickel/Gold [N] 447 + 105% Nickel/Palladium/Gold [N] 768 + 252% OSP [N] 125 - 43% OSP [C] 73 - 66% Silver [C] 287 + 32% Tin [N] 263 + 21% Tin [C] 522 + 239% N = Non-Conveyorized, C = Conveyorized 109 Pollutants Produced Through Energy Production Pollutant Media of Release Environmental and Human Health Concerns Carbon dioxide Air Carbon monoxide Air Dissolved solids Water Dissolved solids Hydrocarbons Air Odorant, smog Nitrogen oxides Air Particulates Air Particulates Sulfur oxides Air Toxic inorganic, acid rain, corrosive Sulfuric acid Water Corrosive, dissolved solids Global warming Toxic organic, smog Toxic inorganic, acid rain, corrosive, global warming, smog 110 Conclusions: Energy Usage HASL has the highest hourly energy consumption rate of all the finishing processes The overall production time is the critical factor which drives the overall energy consumed Energy consumption ranged by ~12X from the lowest to the highest energy consuming processes 111 Design for the Environment Printed Wiring Board Project Performance Demonstration of Surface Finish Technologies 112 Division of Responsibilities Southwest Technology Consultants - Albuquerque Analysis of test results and documentation Raytheon Company - McKinney, TX Environmental exposure and functional electrical testing of LRSTF PWA Contamination Studies Laboratory, Inc. - Kokomo, IN Failure Analysis 113 LRSTF Functional Printed Wiring Assembly Features •PTH and SMT components •23 electrical responses •Circuitry – High current low voltage (2) – High voltage low current (2) – High speed digital (2) – High frequency LPF (6) – High frequency TLC (5) – Other networks (4) – Stranded wire (2) ON HSD PTH PTH SW SMT PTH SMT PTH SMT LRSTF PWA is a good discriminator -- unlike single function test vehicles SMT HF Transmission lines Design Needs Updating HF 114 Overview of Manufacturing Parameters 164 Test Boards 16 Finishing sites 6 Surface finishes HASL OSP Immersion Sn Immersion Ag Ni/Au Ni/Pd/Au 2 Fluxes Low-residue (LR) Water-soluble (WS) 23 Site / surface finish / flux combinations 115 Environmental Test Conditions Pre-test all 164 PWAs 3 Weeks of 85°C / 85% RH Phase 1 Mechanical Shock Thermal Shock Phase 2 www.swtechcon.com 116 3 Weeks Exposure to 85°C / 85% RH Pre-test prior to exposure Post-test after 3 weeks exposure 2 sets of chamber runs used 117 200 Cycles of Thermal Shock -50°C to 125°C with 30 min dwell at each temp Instantaneous change in temperature Test after 200 cycles 2 sets of chamber runs used 118 Mechanical Shock Test Mount PWA in rectangular aluminum frame Drop from 1 meter onto concrete as follows: 5 Times on each face (10 drops) 5 Times on each nonconnector edge (15 drops) Test after drops completed 119 CCAMTF JTP Acceptance Criteria Test results for all 23 circuits were compared to acceptance criteria in the Joint Test Protocol for the LRSTF PWA These criteria require a comparison to Pre-test measurements for 17 of the 23 circuits These criteria were developed for programs currently being conducted by the Circuit Card Assembly and Materials Task Force (21 organizations, 35 individuals) www.swtechcon.com 120 Overall Summary of Success Rates Test Time Pre-test Anomalies Success Rate 2 99.9% 17 99.5% Post TS 113 96.9% Post MS 527 85.4% Post 85/85 Total number of test measurements at each test time: 22* circuits x 164 PWAs = 3608 *HF TLC RNF gave a constant response throughout 121 General Linear Modeling of Test Results All test results were subjected to general linear modeling (GLM) to determine the statistically significant experimental parameters The following GLM was used to analyze site and flux type: Y = 0 + 1D1 + 2D2 + 3D3 + 4D4 + 5D5 + 6D6 + 7D7 + 8D8 + 9D9 + 10D10 + 11D11 + 12D12 + 13D13 + 14D14 + 15D15 + 16D16 + 17D3D16 + 18D4D16 + 19D7D16 + 20D11D16 + 21D14D16 + 22D15D16 Main Effects 2-Factor Interactions 122 General Linear Modeling of Test Results D1 = 0 if not Site 2 = 1 if Site 2 D2 = 0 if not Site 3 = 1 if Site 3 Base Case: all Di = 0 Site 1 with LR flux D15 = 0 if not Site 16 = 1 if Site 16 D16 = 0 if flux is not water soluble = 1 if flux is water soluble 123 General Linear Modeling of Test Results The following GLM was used to analyze surface finish and flux: Y = 0 + 1D1 + 2D2 + 3D3 + 4D4 + 5D5 + 6D6 124 General Linear Modeling of Test Results D1 = 0 if surface finish is not OSP = 1 if surface finish is OSP D2 = 0 if surface finish is not Immersion Sn = 1 if surface finish is Immersion Sn D3 = 0 if surface finish is not Immersion Ag = 1 if surface finish is Immersion Ag D4 = 0 if surface finish is not Ni/Au = 1 if surface finish is Ni/Au D5 = 0 if surface finish is not Ni/Au/Pd = 1 if surface finish is Ni/Au/Pd Base Case: all Di = 0 D6 = 0 if flux is not water soluble HASL with LR flux = 1 if flux is water soluble GLM Results Documented in Report 125 23 Surface Finish and Flux Combinations 1 2 3 4 5 6 7 8 9 10 11 12 13 14 SF HASL HASL HASL HASL OSP OSP OSP OSP OSP Imm Sn Imm Sn Imm Sn Imm Sn Imm Sn Flux LR WS LR WS LR WS LR WS LR LR WS LR LR WS n (site) 8 (1) 8 (1) 8 (2) 8 (3) 4 (4) 8 (4) 8 (5) 8 (5) 8 (6) 4 (7) 8 (7) 8 (8) 8 (9) 8 (10) 15 16 17 18 19 20 21 22 23 SF Flux Imm Ag LR Imm Ag WS Imm Ag WS Ni/Au LR Ni/Au WS Ni/Au LR Ni/Au WS Ni/Pd/Au LR Ni/Pd/Au WS n (site) 8 (11) 4 (11) 8 (12) 4 (13) 8 (13) 8 (14) 8 (15) 8 (16) 4 (16) 126 Multiple Comparisons of SF and Flux The goal of this statistical analysis is to determine which sets of means for surface finish and flux combinations are significantly different from one another. (See Iman, 1994 for details) Note: statistical significance does not necessarily imply practical significance Multiple comparisons results are presented in graphical displays 127 Fisher’s Least Significant Difference Two sets of means are declared significantly different from one another if their absolute difference exceeds Fisher’s least significance difference (LSD), which is defined as LSD t / 2 ,n k where 1 1 MSE n n j i is the level of significance t is the /2 quantile from a Student’s t distribution with n-k d.f. MSE is the mean square error for the model nj and nj are the sample sizes for the means being compared 128 Illustration of a Boxplot Illustration with 5 data points Lower Quartile Median Upper Quartile * Outlier X.25 X.50 X.75 129 Boxplots of HCLVPTH by Site Flux Pre-Test HCLV PTH xplots of HCLV PTH by Site lu (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 7.5 7.4 HCLV PTH 7.3 7.2 7.1 7.0 6.9 WS WS WS WS WS WS WS WS No Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 6.8 WS 130 Boxplots of DPHCLVP by Site Flux Note Use of Post 85/85 - Pre-test Post 85/85 HCLV PTH Boxplots of DPHCLV P by SiteFlux (means are indicated by solid circles) JTP Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 0.5 0.4 DPHCLV PTH 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 WS WS WS WS WS WS WS WS No Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -0.4 WS 131 Boxplots of DPHCLVP by Site Flux Note Use of Post TS - Pre-test Post Thermal Shock HCLV PTH Boxplots of DTHCLV P by SiteFlux (means are indicated by solid circles) JTP Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL DTHCLV PTH 0.5 0.0 WS WS WS WS WS WS WS WS No Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -0.5 WS 132 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post MS - Pre-test Post Mechanical Shock Boxplots of DMHCLV P by SiteFlux HCLV PTH (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd JTP DMHCLV PTH 2 1 WS WS WS WS WS WS WS WS No Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 0 WS 133 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion 4A X 6A Pre-Test HVLC SMT Boxplots of HVLC SMT by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 5.4 5.3 HVLC SMT 5.2 5.1 5.0 4.9 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 4.8 WS Significant Differences - No Practical Differences 134 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion 4A X 6A Post 85/85 HVLC SMT Boxplots of PHVLC SM by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 5.4 PHVLC SMT 5.3 5.2 5.1 5.0 4.9 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 4.8 WS Significant Differences - No Practical Differences 135 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion 4A X 6A Post TS HVLC SMT Boxplots of THVLC SM by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 5.5 5.4 THVLC SMT 5.3 5.2 5.1 5.0 4.9 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 4.8 WS Significant Differences - No Practical Differences 136 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion 4A X 6A Post Mechanical Shock Boxplots of DMHVLC S by SiteFlux HVLC SMT (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 0.05 DMHVLC SMT 0.04 0.03 0.02 0.01 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 0.00 WS SMT Components Came Off the Board During MS 137 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Pre-Test 10-Mil Pads Boxplots of Pads by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 15 14 Pads 13 12 11 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 138 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post 85/85 10-Mil Pads Boxplots of PPads by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 14 PPads Note: Improvement over Pre-test 13 12 11 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 139 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post TS 10-Mil Pads Boxplots of TPads by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 15 TPads 14 13 12 11 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 140 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post Mechanical Shock 10-Mil Pads Boxplots of DMPads by SiteFlux (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 15 DMPads 14 13 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 12 WS 141 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Pre-Test PGA-A Boxplots of PGA A by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 14 PGA A 13 12 11 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 142 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post 85/85 PGA-A Boxplots of PPGA A by SiteFlux (means are indicated by solid circles) PPGA A Note: Improvement over Pre-test Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 13 12 11 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 143 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post TS PGA-A Boxplots of TPGA A by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 15 TPGA A 14 13 12 11 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 144 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post Mechanical Shock PGA-A Boxplots of DMPGA A by SiteFlux (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 14 DMPGA A 13 12 11 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 145 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Pre-Test PGA-B Boxplots of PGA B by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 14 PGA B 13 12 11 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 146 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post 85/85 PGA-B Boxplots of PPGA B by SiteFlux (means are indicated by solid circles) 13 12 PPGA B Note: Improvement over Pre-test Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 11 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 10 WS 147 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post TS PGA-B Boxplots of TPGA B by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 15 TPGA B 14 13 12 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 11 WS 148 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post Mechanical Shock PGA-B Boxplots of DMPGA B by SiteFlux (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 15 DMPGA B 14 13 12 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 11 WS 149 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Pre-Test Gull Wing Boxplots of GullWing by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 14 GullWing 13 12 11 10 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 9 WS 150 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post 85/85 Gull Wing Boxplots of PGullWin by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 14 13 PGullWing 12 11 10 9 8 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 7 WS 151 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post TS Gull Wing Boxplots of TGullWin by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 15 14 TGullWing 13 12 11 10 9 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 8 WS 152 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type JTP Acceptance Criterion > 7.7 Post Mechanical Shock Gull Wing Boxplots of DMGullWi by SiteFlux (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 14 DMGullWing 13 12 11 10 9 WS WS WS WS WS WS WS WS WS NO Significant Differences WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 8 WS 153 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Pre-Test HF LPF PTH 50MHz Boxplots of HF PTH50 by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL -0.3 -0.4 -0.5 HF PTH50 -0.6 -0.7 -0.8 Note:Initial measurement is low -0.9 -1.0 -1.1 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -1.2 WS 154 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post 85/85 - Pre-test Post 85/85 HF LPF PTH 50MHz JTP: 5dB Boxplots of DPHF PTH by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 0.5 Note: Initial low measurement causes subsequent difference to be high 0.4 DPHF PTH50 0.3 0.2 0.1 0.0 -0.1 -0.2 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -0.3 WS Significant Differences - No Practical Differences 155 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post TS - Pre-test Post TS HF LPF PTH 50MHz JTP: 5dB Boxplots of DTHF PTH by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL DTHF PTH50 0.5 0.0 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -0.5 WS Significant Differences - No Practical Differences 156 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post MS - Pre-test Post Mechanical Shock Boxplots of DMHF PTH by SiteFlux HF PTH 50MHz (means are indicated by solid circles) HASL OSP Imm Sn JTP: 5dB Imm Ag Ni/Au Ni/Au/Pd 0 -10 DMHF PTH50 -20 -30 -40 -50 -60 -70 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -80 WS 157 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Pre-Test HF TLC 50MHz Boxplots of HF TL 50 by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL -42 -43 -44 HF TL 50 -45 -46 -47 -48 -49 -50 WS WS WS WS WS WS WS WS Significant Differences WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -51 WS 158 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post 85/85 - Pre-test Post 85/85 HF TLC 50MHz JTP: 5dB Boxplots of DPHF TL by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 5 4 3 DPHF TL 50 2 1 0 -1 -2 -3 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -4 WS 159 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post TS - Pre-test Post TS HF TLC 50MHz JTP: 5dB Boxplots of DTHF TL by SiteFlux (means are indicated by solid circles) Ni/Au/Pd Ni/Au Imm Ag Imm Sn OSP HASL 5 4 3 DTHF TL 50 2 1 0 -1 -2 -3 -4 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 -5 WS 160 Boxplots of Multiple Comparisons Results by Surface Finish and Flux Type Note Use of Post MS - Pre-test Post Mechanical Shock HF TLC 50MHz JTP: 5dB Boxplots of DMHF TL by SiteFlux (means are indicated by solid circles) HASL OSP Imm Sn Imm Ag Ni/Au Ni/Au/Pd 40 DMHF TL 50 30 20 10 WS WS WS WS WS WS WS WS WS WS 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SiteFlux 1 0 WS 161 Circuits Meeting JTP Acceptance Criteria after Each Testing Sequence by Major Circuit Group Circuitry (17) 85/85 (113) Ther Shock (527) Mech Shock HCLV (2) 100.0% 100.0% 51.8% 92.9% SMT HVLC (2) 99.7% 99.7% 50.0% 100% SMT HSD (2) 99.7% 98.8% 99.1% HF LPF (6) 98.7% 89.4% 82.6% HF TLC (5) 100.0% 99.7% 99.4% ON (4) 99.8% 100.0% 100.0% SW (2) 100.0% 99.7% 98.5% Totals 99.6% 96.9% 85.4% 72.5% SMT 162 Breakout of HF LPF Anomalies at Post Thermal Shock by Surface Finish Surface Finish Anomalies HASL OSP 5 (6.8) 8 (7.7) Immersion Sn (7.7)11 Immersion Ag (4.3) 9 Ni/Au 2 (6.0) None 27 28 The hypothesis of the anomalies being uniformly distributed over the surface finishes is rejected using a 25 chi-square test of independence. 11 The p-value is 0.008. 26 (see Iman, 1994 for details). Ni/Au/Pd 0 (2.6) 35 12 129 163 Root of HF LPF Anomalies Open PTH - a break in the metallization within the hole across its length This is a PWB fabrication defect before the surface finish is applied - it not an assembly defect The via is plated with a very thin layer of electroless Cu to provide a “seed bed” for the primary plating Cu is then electroplated over the electroless Cu strike The final finish (Sn, Ag, etc.) is then applied Open PTH occurred in the small via holes in the HF sections small vias are difficult to plate 164 Root of HF LPF Anomalies Open PTH Defect was present at in-circuit and baseline testing Environmental exposure exaggerates this condition Could be related to the strength of the materials - Sn and Ag are relatively weak Need to subject to failure analysis 165 CSL Failure Analysis Summary Observed levels of bromide and weak organic acids (WOA) on all 20 assemblies are typical and therefore not detrimental from an electrochemical standpoint Tested boards with known anomalies exhibit levels near or below CSL’s recommended guidelines, we can say with reasonable confidence that the anomalies are not the result of chloride, bromide, or WOA contamination From an overall contamination standpoint, the five non-HASL surface finishes tested in this analysis performed as well if not better against the HASL finish The few solder joint cracking failures were greater with the HASL finish, than with the alternative finishes. The opens occurred along the interface of the component leads on these older PTH technology boards. www.swtechcon.com 166 Summary of Mechanical Shock Results Changes Observed HCLV PTH is 0.2V higher HCLV SMT is 2.6V higher HVLC SMT - components came off board GW leakage 0.3 orders of magnitude lower - still quite high HSD circuits 0.15ns faster - good Tough Test! www.swtechcon.com 167 Design for the Environment Printed Wiring Board Project Summary of Project Results 168 Risk Conclusions Chemicals in seven process configurations may pose noncancer chronic health risks inhalation concerns: HASL, Nickel/gold, Nickel/palladium/gold and OSP (all non-conveyorized) dermal exposure concerns: HASL (NC & C), Nickel/gold (NC), Nickel/palladium/gold (NC), OSP (NC & C), and Immersion tin (NC) Cancer risk in Nickel gold process due to confidential ingredient (inorganic metallic salt A) less than 1 x 10-6 169 Risk Conclusions, continued Overall, for for potential health risks risks are uncertain for lead in HASL there are chemical risk results for human health above concern levels for all processes evaluated except Immersion silver and conveyorized immersion tin There are chemical risk results for aquatic life above concern concentrations for HASL, OSP, Immersion silver and Immersion tin 170 Cost Comparison of PWB Surface Finish Technologies Overall Cost comparison based on 260k ssf Process 60K ($/ssf) 260K ($/ssf) +/($/ssf) %Change from Baseline HASL [N] $0.37 $0.36 * * HASL [C] $0.36 $0.35 -$0.01 - 3% Nickel/Gold [N] $0.62 $0.60 +$0.24 + 67% Nickel/Palladium/Gold [N] $1.54 $1.54 +$1.18 + 327% OSP [N] $0.11 $0.11 -$0.25 - 69% OSP [C] $0.10 $0.10 -$0.26 - 72% Silver [N] $0.29 $0.28 -$0.08 - 22% Tin [N] $0.19 $0.18 -$0.18 - 50% Tin [C] $0.26 $0.25 -$0.11 -31% 171 Water Consumption of PWB Surface Finish Technologies Surface Finish Process Gal/ssf Change HASL [N] 1.24 --- HASL [C] 0.99 - 20% Nickel/Gold [N] 2.06 + 66% Nickel/Palladium/Gold [N] 3.61 + 191% OSP [N] 0.77 - 38% OSP [C] 0.53 - 57% Silver [C] 0.53 - 57% Tin [N] 1.81 + 46% Tin [C] 0.88 - 29% N = Non-Conveyorized, C = Conveyorized 172 Conclusions: Water Use Several surface finish processes consumed less water than the baseline HASL process reduction primarily due to the reduced number of rinse stages conveyorized processes typically use less water than non-conveyorized Magnitude of savings is facility-dependent Examples: efficiency of previous process, differences between alternatives, facility practices 173 Energy Consumption of PWB Surface Finish Technologies Surface Finish Process BTU/ssf Change HASL [N] 218 --- HASL [C] 133 - 39% Nickel/Gold [N] 447 + 105% Nickel/Palladium/Gold [N] 768 + 252% OSP [N] 125 - 43% OSP [C] 73 - 66% Silver [C] 287 + 32% Tin [N] 263 + 21% Tin [C] 522 + 239% N = Non-Conveyorized, C = Conveyorized 174 Conclusions: Energy Usage HASL has the highest hourly energy consumption rate of all the finishing processes The overall production time is the critical factor, which drives the overall energy consumed Energy consumption ranged by ~12X from the lowest to the highest energy consuming processes 175 Summary of Risk, Resource Use and Cost Comparison to HASL (NC) Surface Finish Alternative Risk Water Energy Cost Overall Cancera NonCancerb Aquaticc HASL (C) = = = to Nickel gold (NC) to Nickel palladium gold (NC) = to OSP (NC) to OSP (C) to Immersion Silver (C) to Immersion Tin (NC) = to Immersion Tin (C) = to a: Based on number of known or probable human carcinogens b: Based on number of chemicals with risk results above concern levels c: Based on number of chemicals with estimated surface water concentrations above concern concentrations = 10% 10-50% better 10-100% worse 50+% better 100%+ worse Design for the Environment Printed Wiring Board Project Implementing Cleaner Technologies in the PWB Industry: Alternative Surface Finishes 177 Overview DfE PWB Project document, “Implementing Cleaner Technologies in the PWB Industry: Surface Finishes” Based on telephone interviews with PWB manufacturers who use the technologies and those who have used and discontinued, and vendors 8 PWB manufacturers, 9 assemblers, 6 vendors 178 ASF Technologies Immersion Silver Enthone Immersion Tin Enthone Florida CirTech Inc. 179 ASF Technologies Organic Solderability Preservative (OSP) MacDermid, Inc. Electrochemicals Electroless Nickel/Immersion Gold Technic, Inc MacDermid, Inc. Electroless Nickel/Electroless Palladium/ Immersion Gold MacDermid, Inc. 180 Operational Improvements Improved coplanarity Reduced maintenance time Reduced costs Lower scrap rate Good press-fit for connections 181 Why Companies Switched Customers’ specifications Anticipated competitive advantage Lead-free process Improved worker safety Appropriate for high-end PWBs 182 Comparisons to HASL Immersion Silver (2 PWB facilities interviewed) Facility A uses Immersion silver on 5% of product, Facility B on 80% of product Reduced cycle time Improved process safety - lower temperatures, less noise Same scrap rate as HASL, but more attention is required for silver because of narrower process window Less maintenance time, but more lab analysis time Facility A gained a small contract as a result, but business has not increased greatly because of the new finish; Facility B has gained some new business Facility A required an XRF to measure silver thickness and auto-unloader for end of line Installation took 2 weeks, debugging 1 week 183 Comparisons to HASL Immersion silver - 1 assembly facility interviewed Facility C specifies Immersion silver because: Lead-Free Wire-Bondable, and works well with solders used Rework does not present any significant problems Simple process Low cost (only OSP is cheaper among ASFs) If a silver board is heated without solder, the silver tarnishes 184 Technology Implementation Suggestions “Arrange and chair a meeting with the chemical supplier and equipment manufacturer to ensure that all specifications are clearly defined.” Facility B Immersion silver “Manufacturers who are installing immersion silver should develop a relationship with the end users to determine the best specifications for the boards.” Facility A - Immersion silver 185 Comparisons to HASL Immersion tin - 3 PWB facilities interviewed Facility F - 15% of product is Immersion tin Facility G - 5% of product is Immersion tin Facility E - 24% of product is Immersion tin All facilities installed their lines in > 1 week Cycle time and scrap similar to HASL Reduction in maintenance from HASL More lab analysis required than HASL Smaller process window than HASL, but better control within that window Improved safety, and reduced energy consumption 186 Comparisons to HASL Immersion tin - 3 Assembly facilities interviewed Drivers for Immersion tin were: Flat, planar finish for fine-pitch SMT Lead-free finish Improvements in hole size tolerance Reduced costs Facility J has switched back to HASL, due to incomplete coverage of boards Facilities H and I are pleased and find that Immersion tin is closest to a drop-in replacement for HASL Does require good handling practices to minimize corrosion and ionic contamination 187 Technology Implementation Suggestions “Make sure you have good quality control and testing procedures in place for this process and that you understand the thickness and coverage of the tin.” Assembler - Immersion Tin “By monitoring and controlling time, temperature, and concentrations, anyone can produce a reliably solderable immersion tin surface finish.” PWB Facility E - Immersion Tin “If you have to get the product wet for any reason prior to completion of any first time soldering operations, be sure not to leave it wet. Blow it off with compressed air to clear the water.” Assembler - Immersion Tin 188 Comparisons to HASL Organic Solderability Preservative (OSP) - 2 PWB facilities interviewed OSP installed at request of large customers about 6 years ago for both facilities Cycle time similar to HASL, maybe a little faster Scrap is less than HASL Less maintenance than HASL Tighter operating window, but better control of finish Improved process safety, less energy usage No effect on ability to recycle scrap boards 189 Comparisons to HASL Organic Solderability Preservative (OSP) - 2 assembly facilities interviewed No compatibility problems with components Facility N has found that OSP can break down on multiple passes; Facility L has found that DI water can remove OSP finish Requires more careful handling Use different machines to do HASL and OSP boards OSP required more heat and a more active flux than HASL 190 Technology Implementation Suggestions “Don’t skimp on equipment. Some try to use old film developers, then have trouble with contamination. Most costs during operation are associated with dragout, which is also equipment-dependent.” Electrochemicals - OSP “As long as the temperature is maintained properly, the same coating is obtained every time.” Facility L OSP 191 Comparisons to HASL Electroless Nickel/Immersion Gold - 2 PWB facilities interviewed Facility M uses Ni/Au on 5% of production; installed a new line 4 years ago in order to reduce the usage of lead, and to retain business Facility O uses Ni/Au on 15 to 20% of production; would like to switch to more Ni/Au, but high cost keeps customers from allowing the switch; installed 2 years ago at request of 3 or 4 customers who desired better planarity and stability; converted unused electroless copper line; has led to a substantial increase in business Increased cycle time, higher scrap than HASL Less maintenance than HASL Increased lab analyses No noticeable improvement in process safety, similar energy usages 192 Comparisons to HASL Electroless Nickel/Immersion Gold - 2 assembly facilities interviewed Facility P’s customers like the flat finish and good press-fit connections;currently 40% of Facility P’s customers use Ni/Au, but that number is decreasing Facility D found that if the gold is too thin, nickel can oxidize leading to a finish to which solder will not bond; also, if the gold bath is not balanced properly, corrosion of nickel surface will cause a weak joint that is subject to fracturing Ni/Au boards are difficult to rework - hard to remove nickel layer without damaging board; also, after rework it is difficult to detect problems 193 Technology Implementation Suggestions “Understand that no technology will be “plug and play.” There must be a commitment from all involved, from manager to equipment operator, to tackle the learning curve and work cooperatively with the supplier. If the new finish is being forced, the resulting resentment will cause the process to turn out poorly. If it is accepted with an open mind by all, then the facility will achieve the cost savings, better planarity, and other benefits that come with the technology.” Supplier - Electroless Ni/Immersion Au “… training someone who can troubleshoot the equipment and chemistry is a valuable component of the installation process.” Facility O - Electroless Ni/Immersion Au 194 Comparisons to HASL Electroless Nickel/Electroless Palladium/ Immersion Gold - No PWB facilities interviewed 5 installations of this process in US, and 10 worldwide Mainly being used on an experimental basis 195 Comparisons to HASL Electroless Nickel/Electroless Palladium/Immersion Gold - 2 Assembly facilities interviewed Facility Q uses this finish on <1% of production; Likes finish due to wire bondability and solderability Facility D uses this finish to reduce “black pad syndrome” that is encountered with nickel/gold Facility Q has found 2 problems - flux incompatibility and intermetallic embrittlement Facility D has not specified this finish due to volatile pricing of palladium 196 Summary of Lessons Learned Thoroughly investigate an alternative surface finish before committing to it Work closely with the supplier and follow their recommendations Everyone, top to bottom in the organization, must commit to and participate in the implementation process Develop a relationship with the end user to ensure that the finish specifications are met Monitor process control closely Purchase your equipment from suppliers experienced with the particular surface finish and invest in the correct equipment 197 Design for the Environment Printed Wiring Board Project Industry Representatives Panel Discussion 198 Design for the Environment Printed Wiring Board Project Closure 199 Requests for Further Information/Publications DfE PWB Project Web Site: www.epa.gov/dfe/pwb Order DfE PWB publications through Pollution Prevention Information Clearinghouse phone: (202) 260-1023 fax: (202) 260-4659 email: PPIC@.epa.gov on the internet: www.epa.gov/opptintr/library/ppicdist.htm 200
