A Moisture Resistant Air Cavity Plastic
Microwave Power Package Capable of
Eutectic Die Attach
Presented at the ECEN5005 SEMINAR
SPONSORED BY IEEE EDS DENVER CHAPTER
UNIVERSITY OF COLORADO, ENGINEERING CENTER, ECEE 265
Thursday March 20, 2003 4:00-6:00 PM
Dave DeWire
RJR Polymers Inc.,
Oakland, California 510-638-5901
Who is RJR Polymers, Inc.
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Headquartered in Oakland California
Technology company
Worldwide Sales and Engineering force
Full service/ solution provider
– Electronic Air Cavity Packaging
– Pre-Applied adhesives
– Air Cavity Lids
– Lidding Equipment
– Engineered Solutions
– Satisfy customer from Prototype to
Volume Manufacturing
RJR’S Market Mix
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RF/ Wireless
Imaging
Medical
Military
WAN/ LAN/ Broadband
Telecom
Automotive
MEM’s, MOEM’s, sensors, etc.
Let’s talk about RF Packaging
• The Perception of RF Power
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Handset ~ 1 watt
Base Station ~ 10 to 200 watts
Broadcast transmitter ~ 1 to 100 kilowatts
Radar – kilowatts to megawatts
For “coverage enhancement” applications it’s
usually a few watts
• Between handset and basestation
• The essence of RF Packaging
– Electrical and environmental performance is a
given
– Thermal dissipation is the key element
– Manage junction temperature
– High performance path(s) to the outside world
– Robust and Reliable
– In this economy - the lowest overall cost while
managing the above is the greatest measure of
success.
Common RF Packaging
• What types are available to
engineers today ?
– Metal
– Ceramic
– LTCC/ Ceramic
– Transfer Molded Plastic
– No Packaging
Package Elements to Consider
Cover material
Lid seal
Sidewall material
Lead seal
Lead material and finish
Base seal
Base material and finish
Plus the process!
• Design
• Assembly
The Range of Thermal Conductivities
400
Thermal Conductivity W/mK
Polymers
350
LTCC
HTCC
300
Alumina
Solder
250
GaAs
Silicon
200
150
Silvar
Copper Moly
Aluminum
100
AlSiC
Copper Tungsten
50
Aluminum Nitride
Hi TC Wcu
Beryllium Oxide
Copper
0
Materials
Some significant new materials in the 25 to 75 W/mK range are
emerging. Ex. Diemat epoxies and Cool Polymers
Advantages/ Disadvantages
• Metal Packaging
– Advantages
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Hermetic
Thermal
Hi Performance
Large Cavities
– Disadvantages
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Costly (largely machined)
Expensive to assemble
Seam Seal/ Laser Weld
Not commercially
acceptable for many
applications
• Weight
Advantages/ Disadvantages
• Ceramic Packaging
– Advantages
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Hermetic
Thermal
Die attach up to AuSn Temps
Operating temperatures are high
– Disadvantages
• Expensive/ Market price
• Can be substantial tooling costs
• Package is inherently costly
– Brazing, etc.
– Laser Machining, pressing, etc.
• Poor Lid Seal surface
• Quality RF feed thru’s are expensive
Advantages/ Disadvantages
• LTCC Ceramic Packaging
– Advantages
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Price
Tooling costs
Good CTE
Multilayering
Low loss conductors (Cu, etc.)
Integrated passives
Miniaturization (small line geometry)
– Disadvantages
• Price vs PCB’s
• Thermal
• Higher Dielectric (7.8 > 20GHz)
Advantages/ Disadvantages
• Plastic Packaging
– Advantages
• Price, Price, Price
• Standard outlines
– Infrastructure advantages
– Disadvantages
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Tooling costs
Thermal
Very Lossy
Marginal High Frequency
Performance
• Thermal
• Non-hermetic
• No Cavity
So what’s new ?
R-Pak Air Cavity Packages !
Adaptable Technology for a
broad range of applications
• Plastic backed for low power
package applications like
sensors
• CCD / CMOS for vision and
optical sensor applications with
glass covers
• Thermally enhanced metal
backed for microwave and
power applications
What is R-Pak ?
• A process that takes the most of the
best elements of traditional packaging
formats and combines them into one
• Works in tandem with the benefits
provided with the use of LCP (Liquid
Crystal Polymers)
• Allows the engineer to “Build” a
package using all the elements
necessary to the device and final
product
• Allows the designer to manage cost
The R-Pak Process
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Packages are molded around
leadframes in a multi-up format
• cost effective for molding
and downstream assembly
Plastic formulated to match the
CTE of copper for low stress
and reliability
Leads are coated with moisture
resistant polymer before
injection molding
RJR ITS equipment supports
package assembly and sealing
RJR’s Injection Molded Packages
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Package Stackup US Pat 6,511,866
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Thermal Base (Cu, WCu, CuMoCu, AlSiC, etc)
Sidewall with leads
Lids with epoxy (pre-applied)
RJR formulated epoxy as interstitial layers
Plastic alloy formulated to match the CTE of Copper
or Copper alloys or Alloy 42 (WCu, CuMo, etc.)
Leads are coated with moisture resistant polymer,
then injection molded US Pats 5,816,158; 6,214,152
The 3 layers are bonded together using RJR
IsoThermal Sealing (ITS) equipment US Pat
5,056,296
RJR Plastic Alloy – HTP-1280
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R-Pak Plastic Body Compound
This custom thermoplastic compound is used in RJR R-Pak plastic body package technology. The following properties are
typical for the bulk material molded into standard test configurations defined by the applicable test method. These property
values are intended for general engineering purposes and are not intended for establishing product specifications.
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Physical:
• Density:
1.67 gm/cc
ASTM D792
• Water Absorption
0.02%
ASTM D570
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Mechanical @ 23C:
• Tensile Strength
21,000 PSI
ASTM D638
• Tensile Modulus
2.5 X 106 PSI
ASTM D638
• Elongation @ Break
1.2%
ASTM D638
• Flexural Strength
31,000 PSI
ASTM D790
• Flexural Modulus
2.4 X 106 PSI
ASTM D790
• IZOD Impact Strength Notched
1.6 ftlb/in
ASTM D256
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Thermal:
• Melting Point
280C (536F)
ASTM D3418
• DTUL @ 1.8 Mpa (264 PSI)
270C (518F)
ASTM D648
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Electrical:
• Volume Resistivity
1012 ohm-cm
ASTM D257
• Surface Resistivity
1017 ohm
IEC 93
• Dielectric Strength
766 V/mil
ASTM D149
• Dielectric Constant
3.8 @ 1 kHz
ASTM D150
3.7 @ 100 kHz
3.7 @ 10 MHz
• Dissipation Factor
0.007 @ 100 kHz
ASTM D150
0.003 @ 10 MHz
ASTM D150
• Arc Resistance
165 Sec.
ASTM D495
• Comparative Tracking Index 175 volts
ASTM D3638
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Chemical Resistance:
• Not affected by: Water, Acetone, MEK, Methyl celusolve, Hexanes, (Sulfuric Acid, Nitric Acid, and HCl) as used
in electroplating baths.
Thermally-Enhanced Package Exploded View
Package lid with pre-applied adhesive
Lid Material: Plastic, Ceramic, Metal, Glass, etc.
Injection molded sidewall
Shown with moisture resistant seal encapsulating the
leads and pre-applied adhesive on bottom surface
Wire Bonds
Device
Solder Preform or Epoxy, etc.
Package Base
Base Material: Cu, Cu/Mo, Cu/Mo/Cu, WCu, Al2O3,
BeO, DBCu, etc.
Completed Package
Epoxy Sealing Materials
• Common properties
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Minimal moisture transmission
Low ionics
Very low volatiles (outgassing)
Cure in minutes for efficient assembly
• Lead primer formulation
– Adherent to LCP and lead finish
– Viscosity supports efficient lead coating process
• Sealing epoxy
– Uniform cover and sidewall coating
– Easily B-staged
Sealing Equipment - ITS
(Isothermal Packaging System)
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Semiautomatic
Custom Designed
and Built Plates
Controls:
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Time
Pressure
Temperature
UPH: 600 - 700*
99% + Yield
** Run Rates are Dependant on
Package Size and Configuration
Thermally-Enhanced Package
Build Process
Process Steps
RJR Polymers
1) Package Base
2) Leadframe with moisture barrier applied
3) Injection mold sidewall over leadframe
4) Nickel and Gold plate leadframe
5) Epoxy coat molded sidewall
Customer location –or- RJR Location
6) Perform Die attach to base leadframe
7) Using RJR’s ITS system – attach assembled base
leadframe to coated injection molded sidewall
8) Wire Bond device to package
9) Using RJR’s ITS system – seal package
lid to molded sidewall
10) Trim, Form and singulate
Advantages/ Disadvantages
• R-Pak Packaging
– Advantages
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Low Cost
Prototype tooling cost is low
Cost Control
High Power
High Frequency
Near Hermetic
Lots of options
Less expensive than Ceramic
Thermal
Flat seal surface
Design Flexibility
Additional Elements (Partial Matching)
– Disadvantages
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Not classically Hermetic
-8
“Near” Hermetic 10
Custom Package Tooling costs (~$60k)
Not the “magic bullet”
The Partially Matched Plastic Package
• The RJR partially matched, air
cavity plastic microwave power
package enables efficient
packaging at 5 GHz
– integrated matching structures
in the package transform very
low device impedance to a
more friendly higher
impedance
– metal base provides high
power dissipation and eutectic
die bonding capability and an
excellent ground return
– lower cost than ceramic
packaging with much more
functionality
3.9mm
Some Other Nice Features
• Moisture Resistant
– pass JEDEC Level I Moisture Pre-Conditioning
• Robust
– pass –65°C to +150°C temp cycle
– Mil-Std 883; Method 1010; Condition C
• High performance
– typically better electrical performance than
ceramic
• Lower cost packages but also
– substantially lower tooling costs.
– rapid prototyping
RELIABILITY TESTING
RESULT
TEST
CRITERIA
SO2F
THERMAL SHOCK
JEDEC A106A, Condition C.
15cycles, +125°C to -65°C
MOISTURE SENSITIVE
JEDEC A112A / J-STD-20-A
+85°C/85%HR, 168hrs
GROSS LEAK
JEDEC A109, Condition C1&3
INTERNAL VISUAL
MIL-STD-883E, Method 2014
JEDEC A112A / J-STD-20-A
CONV OVEN MAX. TEMP +220°C
PACKAGE COPLANARITY
JEDEC A103A
TEMP +150°C, 200hrs.
TEMPERATURE CYCLING
LD2
V32
V48
V52
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
INC
INC
INC
DIE PENETRATION
MIL-STD- 883E, Method 1034
SOLDER REFLOW
STABILIZATION BAKE
SO8
JEDEC B108
PHYSICAL DIMENSIONS
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
INC
INC
INC
INC
INC
INC
INC
INC
INC
INC
INC
INC
INC
INC
20/20
Pass
INC
INC
INC
MAX/MIN
MAX/MIN
MAX/MIN
JEDEC B100A
JEDEC A104B, Condition B
100 CYCLES, +125°C to -55°C
PRECONDITIONING
JEDEC A113B
+85°C/85%HR, 168hrs
N= 20
WIRE PULL STRENGTH
WIRE BONDABILITY
MIL-STD-883E, Method 2011.7
N= 20
MAX/MIN
10.5g 8.5g
12.1g 8.1g
MAX/MIN
MAX/MIN
XX.Xg X.Xg XX.Xg X.Xg XX.Xg X.Xg XX.Xg X.Xg XX.Xg X.Xg
XX.Xg X.Xg XX.Xg X.Xg XX.Xg X.Xg XX.Xg X.Xg XX.Xg X.Xg
INTERNAL VISUAL
DIE ATTACHABILITY
MIL-STD-883E, Method 2010.10
& 2017.7
N= 20
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
20/20
Pass
In Summary
Eutectic Die Attach in an Air Cavity Plastic Package !
The R-Pak low cost injection molded
packaging process combines the thermal
advantages gained by using a eutectic die
attach material between die and backplane
with a moisture resistant plastic sidewall
specifically designed to manage higher
frequency and power.
Features:
• Eutectic Die attach
• Moisture resistant
• Low CTE
• CTE matched package
• Low Dielectric
• Low Parasitics
• High Power
• High Frequency
• Low Cost !
Package Applications:
• RF/ Microwave
• WLAN/ LAN
• Short Range Wireless
• MEMS/ MOEMS
• LDMOS
• CCD/ CMOS
Thank You