a moisture resistant air cavity plastic microwave power package capable of eutectic die attach

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

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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