“Lead free” Status in the
Semiconductor Industry (E3)
and at
Philips Semiconductors
R. Geppert
Philips Semiconductor Marketing and Sales
Quality Manager, Area Central
2004-09, Hamburger Lötzirkel, “Leadfree Soldering”
Content
•
•
•
•
•
Legislation / RoHS conformity
Supply chain
J-STD 020
Technology
Status at Philips Semiconductors
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Opening Statement:
Main part of this document is based on a joint
activity of STM / Philips SC / IFX (E3) on leadfree packaging
The E3 initiative was formed in 2001 to push for
standards, share workload and to give best
support for our customers
Recently, Freescale Semiconductor joined to
form “E4”
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Legislation
Effect of EU Directive
• On 13th of February 2003, directive 2002/95/EC of the
European Parliament and of the Council of 27th January 2003
on the Restriction of the use of certain Hazardous Substances
in electrical and electronic equipment (RoHS) entered into
force. The directive will be applicable throughout EU by
1st July 2006 for the ban on the use of certain substances
including lead (Pb)
• Considering that semiconductor devices as well as finished
electronics can be stored before usage or selling, conversion
to lead-free should take place with suitable advance on the 1st
July 2006 deadline
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Leadfree / RoHS
Overview and status Philips Semiconductors:
Substance
banned (not present)
Cadmium
Mercury
Chromium-VI
PBB and PBDE
Lead
9
9
9
9
“Leadfree” program
==> All products are RoHS compliant after
Leadfree conversion!
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Target / Status: What is “lead free” ?
• Phase 1: Lead (Pb) free terminals
– Matte Tin (Sn100) or NiPdAu solution for (leaded) packages
– Lead free solder spheres (SnAgCu) for BGA packages
• Phase 2: Lead (Pb) free board soldering process
– higher temperature needed
– assess package MSL and reliability of lead free soldering process
• Phase 3: Lead (Pb) free inside package (partially
exempted)
– lead free die attach (alloy)
– lead free solder bumps (flip chip)
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Target / Status
Pb-free Programs in the Industry
Two Targets:
• Compatibility with both SnPb and Pb-free board soldering
(with extended temperature range)
• Elimination of Pb in package terminals (leads, balls, bumps)
Status
• Japan consumer market substantially converted to lead-free
soldering in 2002
• Ramp up of Pb-free components shipment in volume in 2003
• Philips Semiconductors:
– “Discretes”:
– “IC packages”:
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SMD-packages completed Q3/03, others Q4/04
majority of packages finished by Q1/05
7
Supply Pipeline (worst case)
Supplier
Customer
Customer Stock
FIFO Stock
Lead
Leadfree
Product age at delivery:
max. 12 months ICs
max. 24 months Discr.
up to 12 months
In total: up to 24 / 36 months !
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Standardisation
IPC/JEDEC J-STD-020B, and upcoming -020C
• E3 procedures are conform with the J-STD-020B
• Existing results are compliant to J-STD-020B
• Enhanced conditions for small packages:
STM, Philips and Infineon agree to introduce an
additional profile with 260°C -5/+0 °C for testing
MSL of small devices at higher temperature.
• New J-Std-020C increases temperature stress by
setting the limits to -0/+5°C
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MSL practise, 020C based
New Test conditions due to J-STD-020C
Source: SNW-FQ-225B 2004-04-02
260°C-Rework compatibility test started in April 2004.
Plan : all packages will be re-classified in Q1/05.
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Convection Solder Flow Requirements, based on JSTD-020C:
Tp
tp
Max Ramp Up Rate = 3oC/s
Max Ramp Down Rate = 6oC/s
Temperature
TL
Tsmax
Tp - 5oC
tL
Preheat Area
Tsmin
ts
25
0
o
Time 25 C to Peak
Time
Reflow Condition
Average ramp-up rate
(TL to Peak)
Preheat
- Temperature Min (Tsmin)
- Temperature Max (Tsmax)
- Time (min to max) (ts)
Tsmax to TL
- Ramp-up Rate
Time maintained above:
- Temperature (TL)
- Time (tL)
Peak Temperature (Tp)
Time within 5°C of actual Peak Temperature (tp)
Ramp-down Rate
Time 25°C to Peak Temperature
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SnPb Process
Pb-Free Process
3°C/second max.
3°C/second max.
100 °C
150 °C
60-120 seconds
150 °C
200 °C
60-180 seconds
3°C/second max.
3°C/second max.
183°C
60-150 seconds
See Table 2-1
10-30 seconds
6°C/second max.
180-360 seconds.
217°C
60-150 seconds
See Table 2-2
20-40 seconds
6°C/second max.
300-480 seconds
Source: Philips Semiconductors, SNW-FQ-225B
11
MSL statements
• About 500 different packages
tested in the 3 companies
according to the agreed
profiles, following JEDEC
Higher MSL as temporary action,
STD-020B for the prequalification of new materials
conditioning process and for
(ongoing) as short/mid term action
failure criteria. 245°C profile
applied to large packages
(>350mm3) and 260°C
applied to small packages
(<350mm3)
• With present materials and
package design, in specific
cases an increase in MSL
Source Infineon
classification may be observed
• Plus 10°C means MSL up one
level! (020C effect)
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Technology
Consolidated lead free solutions:
For lead frame based packages:
• Post plate of matte tin (Sn)
• Pre plate of NiPdAu
For Ball Grid Array packages:
• SnAgCu
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Technology
Postplate of matte tin (Sn)
Main characteristics:
•
•
•
•
•
Material availability is good
Closest to SnPb in cost and process
Good solderability with PbSn and Pb free solders
Good solderjoint reliability
“Whisker free” process available 1)
( 1) See whisker presentation )
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Whisker on Cu
Whisker Mechanism
Whiskers grow because of compressive stress in the plating which is caused
by irregular growth of intermetallics
Tin Whisker
is forced out
Cu6Sn5
Sn Deposit
Whisker
Cu Substrate
Cu6Sn5
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Source: Philips
15
Whisker on Cu
Storage conditions
• Test data showed that whiskers grow longest at room
temperature
• Explanation: irregular intermetallic growth
1,9 µm ambient
250
length of longest whisker in µm
1,9 µm 55 °C / ambient
1,9 µm 85 °C / 85 % r.h.
200
150
longest whisker broken,
continued with second longest
100
50
time in days
0
0
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50
100
150
200
250
300
Source: Infineon
16
Whisker on Cu
1,82 µm
3.5 µm
5.35 µm
7.10 µm
length of longest whisker in µm
10.10 µm
Source:
STMicroelectronics
160
Protection by Thickness
Thicker Sn layer can absorb more stress.
Note: irregular intermetallics still present!
Sn-plating @ Room Temperature
120
80
40
0
Semiconductors 0
50
100
150
200
250
time in days 700
750
17
Whisker on Cu
Protection by Post bake (1h, 150 oC)
Longest Whisker (µm)
No whiskers have been detected after postbake of 1 hour at 150 oC for
any thickness of Sn plating up to 1 year after plating and storage at
ambient temperature and atmosphere.
30
2 µm Sn
5 µm Sn
10 µm Sn
20
10
0
0
100
200
300
400
Time (days)
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Source: Infineon, STMicroelectronics, Philips
18
Whisker on Cu
Protection by Post bake (1h, 150 oC)
• Because of higher temperature diffusion will shift from grain boundary to
bulk diffusion and thus regular intermetallics
• Annealing of stress
No whisker!
Bulk diffusion
Cu6Sn5
Sn Deposit
Cu Substrate
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Technology
Preplate NiPdAu
Main characteristics:
•
•
•
•
Good solderability with PbSn and Pb free solders
Good solder joint reliability
Used in high volume
Offered by major lead frame suppliers
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Technology
SnAgCu Spheres in Ball Grid Array
Main characteristics:
•
•
•
•
SnAg3.0-4.0Cu0.5-1.0 is the most applied range
Good solderability with Pb free solders
Offered by all major suppliers
Limited backward compatibility with SnPb
solders
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L/F packages Compatibility
customer
Pb - solder
supplier
Pb - solder
Increase temp. by 20°C
component finish
Pb
Pb
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Today
Processability:
o.k.
Experience of some
Solderability:
o.k.
decades of board assembly
Reliability:
o.k.
(NCMS-, IDEALS-report,internal evaluations)
Processability:
o.k.
Processability:
o.k.
Solderability:
o.k.
Solderability:
o.k.
Reliability:
o.k.
Reliability:
o.k.
22
L/F packages Processability
Processability in lead containing vs. lead-free process
• For reflow soldering: paste application, component
placement do not require special measures
• For wave soldering: glue application, component placement,
glue cure do not require special measures
• Differences in soldering process are time and
temperature
• SnPb plating and Sn plating do not show a different behavior
in the soldering processes (more than a decade of experience!)
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L/F packages Processability
Reflow solder joints
Lead containing solder
Backw ard Com patibility SC
SnPb36Ag2
Lead-free solder
300
260
260
250
205
200
150
FQFP208
HVQFN48
VSO56
HTQFP100
SO28
100
50
0
Temperature in degree C
Temperature in degree C
Backw ard Compatibility SC, reduced dT
SnAg3.8Cu0.7
300
250
235
200
150
FQFP208
100
HVQFN48
VSO56
50
HTQFP100
SO28
0
0
100
200
300
400
0
60
120
Tim e in seconds
Only slight differences of wetting (
) , fillet (
Surface: less shiny for lead-free (see inserts)
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180
240
300
360
420
Tim e in seconds
)
Source Philips
24
L/F packages Processability
Wave solder joints
Lead containing solder
Lead-free solder
Process
Process
speed
[m/min]
Total soldering
time/temp
Pre-heat
temperature
Leaded
1.25
2.75±0.25s / 250°C
120±10°C
Lead-free
1.2
3.75±0.25s / 265°C
120±10°C
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Only difference:
somewhat less shiny with lead-free
Source Philips
25
L/F packages Reliability
Temperature Cycling as reliability test for solder joint
• Temperature cycling causes thermo-mechanical solder fatigue
• Degradation/failure goes along the following path:
– Diffusion and re-crystallization
– Crack initiation and growth
– Failure by macroscopic solder fracture
• Solder fatigue failure is visualized and analyzed according
Weibull statistics
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L/F packages Reliability
Weibull analysis of failure in temperature cycle test
(-40/125 oC) lead-free and lead-containing reflow solder
Sn plated VSO56 (FeNi42-leadframe)
VSO56, reflow
ln[1/(1-f)]
10
1
SnPb
SnAgCu
0,1
0,01
100
1000
10000
N cycles
Source Philips
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BGA packages Compatibility
customer
Pb - solder
supplier
Pb - solder
Increase temp. by 20°C
component finish
Pb
Pb
Today
Processability:
o.k.
Experience of some
Reliability:
o.k.
Processabilty below 230°C critical
Processability:
o.k.
Reliability: o.k. (improved to SnPb)
Reliability:
o.k.
decades of board assembly
For low temperatures critical
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BGA Processability
Motivation:
For array-package the processability has
been tested. Different temperature at the
ball result in different mounting height.
Conclusion:
The combination lead-free BGA/SnPb-paste
can be processed with a minimum
temperature of 230°C (at the ball).
Due to restricted self-alignment, a peak
temperature at 220°C should only be
chosen in exemptional cases
decreasing mounting height
Beginning melting
Complete melting, final height
Peak temperatures over 230°C
are recommended
mounting
height
bad joint
good solder joint
with limited drop
good solder
joint
Source Infineon
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Conclusion
Leadframe packages:
• Sn-plating or NiPdAu-plating will be introduced as lead-free
technology's
• For leadframe packages there is a full compatibility to SnPb- and
Pb-free solder process
BGA packages:
• For BGA packages SnAgCu is the chosen metallurgy
• On board reliability is proven
• In the case of BGA-packages the soldering temperature must be
above 230°C for processability
Please note:
The major conversion will take place in 2004: Now !
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Current Status at Philips Semiconductors
Compatibility “Lead” vs. “Lead Free”
• Backward Compatibility
– Pb free products in Pb-containing soldering process:
– Report (.pdf) available
• Forward Compatibility
– MSL re-assessment done (J-STD-020B !!), check
MSL value on label
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Conversion Status / Roadmaps - 1
Discretes:
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Pb-free / Green Indicators
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Pb-free/Green Identification on Packing
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Pb-free/Green Identification on Component
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PS approach to logistics control
•
•
No change in part numbers and 12NC when we introduce
leadfree products
Lead and leadfree products flow will be separated by
–
–
•
•
•
•
•
One packing quantity (PQ)
No mix of PQs in one box
Traceability will be by date code
Separate stores for lead and leadfree products
Leadfree products will be identified by a marking on the
product (where space allows)
Packaging will be marked by a leadfree sticker on the box
The Leadfree symbol will be printed on the label
–
At Packing Quantity level (box/reel – not tube)
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Discontinuation of Products ?
• No product will be discontinued only because
of L/F conversion (see normal DN distribution)
• BGA types will get new P/N
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Please visit our Internet for further details
www.semiconductors.philips.com/green_roadmap/
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Early Information:
Chemical Content
SOT612CB3 HLQFP144
Total Product weight: 1.30 g
Part
Leadframe
Material
CuCr
Cu
Cr
Details
100
%
99.25 %
0.3 %
Weight
0.27 g
0.268 g
0.002 g
Leadfinish
SnPb15
Sn
Pb
100
85
15
0.05 g
0.04 g
0.01 g
%
%
%
etc.
Proh./ Res. Materials
Cadmium < 100 ppm
PBB
< 100 ppm
etc.
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Packing info
Tube packing; Chemical contents
Tray packing ; Chemical contents
analyses/
reports
DISCLAMER
STATEMENT
42
Thank you for your attention.
Any Question?
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IMDS . . . .
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Chemical Content information on Internet
• Check following link:
http://www.semiconductors.philips.com/
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Chemical Content information on Internet /2
• Enter product type, e.g.: 74HC00
• Wait for search results and then select link to
“info” page
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Chemical Content information on Internet /3
• You get all product related info, incl. “ChemCon”,
when selecting ‘package’ link
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Chemical Content information on Internet /4
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