Date post: | 03-Jan-2016 |
Category: |
Documents |
Upload: | destiny-hawkins |
View: | 122 times |
Download: | 1 times |
A Moisture Resistant Air Cavity Plastic Microwave
Power Package Capable of
Eutectic Die Attach
John W. Roman, Richard Ross, Tony Shaffer, Dave DewireRJR Polymers Inc., Oakland, California 510-638-5901
RJR Polymers Inc.
• Headquartered in Oakland, CA• Worldwide sales and engineering force• Manufacturer of injection molded plastic packages,
pre-applied adhesives and equipment
Provider of engineered solutions to our customers’ demanding product and process applications. partners
R-Pak Air Cavity Packages
• 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
• 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
The R-Pak Process
RJR’s Injection Molded Packages • Package Stackup
• 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 (WCu, CuMo, etc.) • Leads are coated with moisture resistant polymer,
then injection molded• The 3 layers are bonded together using RJR
IsoThermal Sealing (ITS) equipment
1) Package Base
Thermally-Enhanced Package
Build Process
2) Leadframe with moisture barrier applied
3) Injection mold sidewall over leadframe
4) Nickel and Gold plate leadframe
5) Epoxy coat molded sidewall
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
Process StepsProcess Steps
RJR Polymers
Customer location –or- RJR Location
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, etc.
Completed Package
Moisture Resistance
• IPC/JEDEC J-STD-202B Moisture/Reflow Sensitivity Classification for Nonhermetic Solid State Surface Mount Devices– intended to classify “nonhermetic solid state SMDs” by moisture
sensitivity to ensure that proper handling precautions are applied– Applies to plastic SMDs with cavity or without cavity
• Basic issue is vapor pressure change of water during solder reflow cycle causing damage– Delamination, cracking, leaks, “popcorning”
• Low moisture sensitivity comes from choice of materials, design of package and good processes
Hermeticity
• JEDEC standard JES D22-A109-A defines test procedures– Derivative of MIL-STD-883, Method 1013
• Historic military definition of “hermetic” means sealed to a specified helium leak rate– Assumes cavity package– Excludes organic seals or materials
Nonhermetic and Near Hermetic
• Rationale that organics are “non-hermetic” based on diffusion rates of water through organic materials– Metal, ceramic and glass are considered hermetic– New organic materials challenge that definition
• Near Hermetic is a common term without a clear definition
• Moisture getters further confound the issue
Package Elements to Consider
Cover material
Lid sealSidewall materialLead seal
Lead material and finish
Base sealBase material and finish
Plus the process!• Design• Assembly
Superex Polymer Inc.
Why Liquid Crystal Polymer?
RJR Plastic Alloy – HTP-1280• 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.
– Physical:• Density: 1.67 gm/cc ASTM D792• Water Absorption 0.02% ASTM D570
– 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
– Thermal:• Melting Point 280C (536F) ASTM D3418• DTUL @ 1.8 Mpa (264 PSI) 270C (518F) ASTM D648
– 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 kHz3.7 @ 10 MHz
• Dissipation Factor 0.007 @ 100 kHz ASTM D1500.003 @ 10 MHz ASTM D150
• Arc Resistance 165 Sec. ASTM D495• Comparative Tracking Index 175 volts ASTM D3638
– Chemical Resistance:• Not affected by: Water, Acetone, MEK, Methyl celusolve, Hexanes, (Sulfuric Acid, Nitric Acid, and HCl) as used
in electroplating baths.
Epoxy Sealing Materials
• Common properties– 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
Process• Design
– Appropriate sidewall thickness
• Molding process– Tool design and process control
• Epoxy application– Complete 4 sided primer application– Consistent application to sidewall and cover
• Package assembly process– Isothermal Packaging System (ITS)
• Lead forming– Tool design critical to maintaining package integrity
Sealing Equipment - ITS (Isothermal Packaging
System)• Semiautomatic • Custom Designed
and Built Plates• Controls:
• Time• Pressure• Temperature
• UPH: 600 - 700*• 99% + Yield
** Run Rates are Dependant on Package Size and Configuration
Isothermal Packaging System
• Lid is held up during temperature ramp up• At temperature, lid is released onto package• Piston applies pressure to lid preventing pinholes and blowouts
ITS programmed cycle
Thermally Enhanced R-Pak
• Moisture resistant and near hermetic• Capable of eutectic die attach• High thermal dissipation capability• High frequency capability
– parts in service at 5.8 GHz
• Can pass JEDEC Level I Moisture Pre-Conditioning
• Pass Mil-Std 883 Section 1010 Condition C temp cycle
RELIABILITY TESTING
MOISTURE SENSITIVEJEDEC A112A / J-STD-20-A
+85°C/85%HR, 168hrs
THERMAL SHOCKJEDEC A106A, Condition C.15cycles, +125°C to -65°C
TEST CRITERIA RESULT
SO2F SO8 V32 LD2 V48
SOLDER REFLOWJEDEC A112A / J-STD-20-A
CONV OVEN MAX. TEMP +220°C
WIRE BONDABILITY
DIE ATTACHABILITY
STABILIZATION BAKEJEDEC A103A
TEMP +150°C, 200hrs.
PRECONDITIONINGJEDEC A113B
+85°C/85%HR, 168hrs
TEMPERATURE CYCLINGJEDEC A104B, Condition B
100 CYCLES, +125°C to -55°C
GROSS LEAKJEDEC A109, Condition C1&3
DIE PENETRATIONMIL-STD- 883E, Method 1034
INTERNAL VISUALMIL-STD-883E, Method 2014
PHYSICAL DIMENSIONSJEDEC B100A
V52
N= 20
INTERNAL VISUALMIL-STD-883E, Method 2010.10
& 2017.7
N= 20
WIRE PULL STRENGTHMIL-STD-883E, Method 2011.7
N= 20
PACKAGE COPLANARITYJEDEC B108
20/20 Pass
20/20 Pass
20/20 Pass
20/20 Pass
20/20 Pass
20/20 Pass
MAX/MIN
10.5g 8.5g12.1g 8.1g
MAX/MIN
XX.Xg X.XgXX.Xg X.Xg
20/20 Pass
20/20 Pass
20/20 Pass
20/20 Pass
20/20 Pass
20/20 Pass
MAX/MIN
XX.Xg X.XgXX.Xg X.Xg
MAX/MIN
XX.Xg X.XgXX.Xg X.Xg
MAX/MIN
XX.Xg X.XgXX.Xg X.Xg
MAX/MIN
XX.Xg X.XgXX.Xg X.Xg
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
20/20Pas
s
INC
INC
INC INC INC
INC INC INC INC INC
INC INC INC INC INC
INC INC INC INC INC
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
Eutectic Die Attach in an Air Cavity Plastic Package !
Sealing EquipITS AITSDe-reelers
Prototype Design
And Assembly
Pre-applied Adhesives
Injection Molded Plastic
Packages
www.rjrpolymers.com