Power Device Packaging

Zhenxian Liang

Oak Ridge National Laboratory

May 15, 2012

Project ID: APE023 This presentation does not contain any proprietary, confidential, or otherwise restricted information

2012 U.S. DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

2 Managed by UT-Battelle for the U.S. Department of Energy

Overview

• Start Date: Oct. 2009 • End Date: Sept. 2014 • 70% Complete

• Existing inverters are twice the cost of the DOE 2020 target. Power modules make up 50% of the inverter’s cost

• State-of-the-art (SOA) technologies have limitations in electrical, thermal, and reliability performance, as well as high manufacturing costs.

• Targets: – 40% cost reduction and 60% power

density increase of the power module, in line with DOE power electronics 2020 targets. • DOE Share – 100%

• FY10 received: $480K • FY11 received: $650K • FY12 received: $672K

Timeline

Budget

Barriers

• ORNL Team Members: Puqi Ning, Andy Wereszczak, Randy Wiles, Laura Marlino

• The University of Tennessee: Fred Wang

Partners

3 Managed by UT-Battelle for the U.S. Department of Energy

Objective The fundamental efforts of this project are to: • Identify the limitations and shortcomings with existing device packaging

approaches; • Develop new packaging concepts for improved electrical, thermal

performance, manufacturability, and reliability; • Complement other power electronics research efforts within the Vehicle

Technology Program.

FY12 • Evaluate industry SOA power modules: Packaging performance, material,

processing and structure analysis. • Planar_Bond_All (PBA) power module development

Packaging process optimization: Material/structure, cost-effectiveness manufacturing.

Prototype module fabrication: Integration of advanced processing techniques.

Module testing and analysis: Electrical, thermal, properties measurement and analysis.

• Provide packaging support for other VTP APEEM projects: Fabrication of customer-specific power modules.

4 Managed by UT-Battelle for the U.S. Department of Energy

Milestone • Sept. 2011 - Selected advanced packaging candidate technologies. • Go No/Go Decision Point: Determine if prototype PBA

technology could potentially meet the performance and power density targets.

• Sept. 2012 -Test PBA modules to confirm improvements in electrical

and thermal performance. -Provide prototype modules for Segmented Drive

Inverter Project (APE004) and Wide Bandgap Project (APE003).

• Go/No Go – Determine if PBA modules can meet the targets on cost and reliability.

5 Managed by UT-Battelle for the U.S. Department of Energy

Approach Overall Strategy • Benchmark existing power device packaging technologies,

including package configuration, materials characterization, processing, and thermal and electrical performance evaluations. Determine the “weak links”.

• Develop new packaging approaches through simulation and experiments to improve power module electrical, thermal, thermo-mechanical performance and manufacturing cost-effectiveness.

• Apply packaging expertise to provide customer-specific power modules to VTP projects.

Status of Milestone • FY11 PBA prototype completed

• FY12 - PBA optimized module fabricated; Testing is underway;

- Customer modules delivered.

6 Managed by UT-Battelle for the U.S. Department of Energy

1.0E-3

1.0E-2

1.0E-1

1.0E+0

1.0E+1

0 1 2 3 4 5 6

Ther

mal

Tim

e C

onst

ant (

S)

Order Number

Prius_One_die

Prius_two_die

Infineon HP1

FY11/12 Technical Accomplishments Benchmark: Thermal Performance Characterization of SOA Modules

Infineon® HybridPack1™ under test

Thermal Resistance Comparison

Junction temperature cooling down curve Thermal model

Thermal Parameters

ToyotaPrius10_OneDie

ToyotaPrius10_TwoDie InfineonHP1 NissanLeaf

Thermal Resitance (C/W) 0.43 0.22 0.27 0.31Die area (10xcm2) 0.11 0.22 0.20 0.22Specific Thermal resitance

(Cm2.C/W) 0.47 0.49 0.54 0.68

00.10.20.30.40.50.60.70.8

7 Managed by UT-Battelle for the U.S. Department of Energy

0.44 mΩ

11.3 nH14.4 nH

Positive

7 mΩ19.6 nH

Negative

Neutral

7 mΩ19.6 nH

0.33 mΩ

0.17 mΩ0.18 mΩ7.3 nH 6.5 nH

0.44 mΩ11.3 nH14.4 nH

0.33 mΩ

0.17 mΩ0.18 mΩ7.3 nH 6.5 nH

0

50

100

150

200

250

300

350

400

0 0.5 1 1.5 2 2.5

Ice

(A)

Vce (V)

IGBT I-V Curve

P-side S-side

0

100

200

300

400

500

0

50

100

150

200

250

0 200 400 600 800 1000 1200

Volta

ge (V

)

Cur

rent

(A)

Time (nS)

Ice

Vce (S-Side)

Vce (P-Side)

IGBT Switching Curve

FY11/12 Technical Accomplishments Benchmark: Electrical Performance Characterization of SOA Modules

Nissan LEAF under Test

Prius 2010 Module 3_D Electromagnetic Model Lump element model of parasitic electric parameters

8 Managed by UT-Battelle for the U.S. Department of Energy

Die attach solder layer in Infineon HP1 Metallurgical compositions on top of IGBT die in Mitsubishi TPM_II

Insulator sheet in Nissan LEAF™ module Polyimide bond line

FY11/12 Technical Accomplishments Benchmark: Micro-structural analysis of packaging structures/materials

9 Managed by UT-Battelle for the U.S. Department of Energy

High power density integrated traction machine drive

Reduced stray inductance power module

Segmented drive Module HT Power SiC diode package.

Prototype: Customer-specific power modules FY11/12 Technical Accomplishments

10 Managed by UT-Battelle for the U.S. Department of Energy

Patent Pending: serial number 61/509312

Power Semiconductors stage

Integrated Advanced Cooler

Integrated Advanced Cooler

Planar_Bond_All Power Module Prototype

Planar Bond Power Stage Electrical Connection

FY11/12 Technical Accomplishments Develop: Planar_Bond_All power module

Advanced Power Module Concept

3-D planar Electrical Interconnection

Integrated, Double Sided Cooling

Symmetrically Mechanical Structure

Cost-effective Manufacture

11 Managed by UT-Battelle for the U.S. Department of Energy

Wire Bond Packaging

1 Substrate Preparation

3 Substrate Attach

2 Die Attach 4 Terminal Frame Attach

5 Wire Bond 6 Encapsulate 7 assembly

FY12 Technical Accomplishments Develop: Advanced manufacturing process

Patent Pending: serial number 61/509312

Planar_Bond_All

1st step: assembly

2nd step: heating profile

products

12 Managed by UT-Battelle for the U.S. Department of Energy

-400 -200 0 200 400 0

100

200

300

400

500

Time (ns)

Ice

(A),

Vce

(V),

P (W

/0.0

03),

E m

J/15

)

Ice Vce

Eoff

Poff

ToyotaPrius10 PlanarBondAllLp (nH) 50.3 12.8

Rp(0.1xmOhmic) 23.5 2.2

0

10

20

30

40

50

60

Electrical Parameters

Comparison

-600 -400 -200 0 200 400 600 0

50

100

150

200

250

300

350

400

450

500

Time (nS)

Vce(

V)

L: 45nH

30nH 20nH 15nH 10nH 5nH

FY12 Technical Accomplishments Develop: Analysis of electrical performance of PBA module

Lump element model of PBA module Parasitic parameters comparison

Simulation of IGBT switching Voltage overshoot vs. parasitic inductance

13 Managed by UT-Battelle for the U.S. Department of Energy

Inductance (nH) Experimental Value Calculated Value

Planar Bond_Lower IGBT 10.5 6.3

Wire Bond-Lower IGBT 31.9 23.5

0 100 200 300 400 500 600 0

20

40

60

80

100

120

140

160

180

Time(S)

Pow

er L

oss

(W)

Rp=0.22mΩ, P=1.030W Rp=2.35mΩ, P=11.08W

10

15

20

25

0 20 40 60 80

Eoff

(mJ)

Parasitic Inductance (nH)

X

X

Lp=10.5nH, Eoff=15.6mJ Lp=31.9nH, Eoff=17.2mJ

0

50

100

150

200

250

300

350

400

450

500

0

20

40

60

80

100

120

140

160

180

200

0 500 1000 1500 2000

Volta

ge (V

)

Cur

rent

(A)

Time (nS)

∆Vce(WB)=156V ∆Vce(PB)=72V

Ice Vce

FY12 Technical Accomplishments Develop: Analysis of electrical performance of PBA module

Comparison: PBA vs. wire bond module Voltage overshoot: PBA vs. wire bond

Switching loss: PBA vs. wire bond Conduction loss: PBA vs. wire bond

14 Managed by UT-Battelle for the U.S. Department of Energy

NissanLeaf ToyotaPrius10 PlanarBondAllSpecific Thermal resitance

(Cm2.C/W) 0.52 0.471 0.334

0

0.1

0.2

0.3

0.4

0.5

0.6

Thermal Resistance

θja,sp

29.1%

)($ ,

aj

spjaAreaDie

TTPS

kW −

•=∝

θη

FY11/12 Technical Accomplishments Develop: Analysis of thermal performance of PBA module

3-D Thermal Model of PBA module with mini-cooler Temperature distribution with cooling

PBA module under thermal test Measured Thermal parameter comparison

15 Managed by UT-Battelle for the U.S. Department of Energy

Ag Bonded DBC Substrates

Bond Line View After Tear Down

Cross sectional View of Bond Line

Bond Strength vs. Topography

FY12 Technical Accomplishments Develop: New bonding material and processing

16 Managed by UT-Battelle for the U.S. Department of Energy

Collaboration and Coordination • NREL

– Will use ORNL supplied modules to develop reliability parameters

• ORNL Materials Science and Technology Division – Leveraged DOE VTP Materials Program – Coordinated research to address packaging materials needs

• University of Tennessee – Assisted in benchmarking commercial packages

• Virginia Tech University – Collaborated on die attach material and power electronics module

packaging

17 Managed by UT-Battelle for the U.S. Department of Energy

Future Work – FY12 • Complete development of PBA processing

portfolio – Complete the die top electrode design and fabrication

process;

– Complete the insulation processing for solderable front metal (SFM) power semiconductor switches;

– Assemble all individual steps into one processing run;

– Finish the electrical and thermal performance tests. • Continue to benchmark packaging technologies

(performance, materials and processes) • Continue to support new power electronics module

development

18 Managed by UT-Battelle for the U.S. Department of Energy

Future Work – FY13 and Beyond • Enhance reliability of PBA concept

– Perform thermo-mechanical design and simulation of advanced planar bond module packages;

– Implement cost-effective materials and structures into PBA power modules;

– Conduct simulations and preliminary reliability tests of packages. • High temperature module packaging development

– Incorporate advanced bonding material/processing techniques; – Investigate new encapsulate, thermal materials; – Evaluate the high temperature effects of power module on cost,

efficiency and reliability, including Si, SiC and GaN power semiconductors.

• Continue to benchmark SOA technologies as needed (module performance, materials evaluation and processing)

• Provide packaging support for other projects

19 Managed by UT-Battelle for the U.S. Department of Energy

Summary • Developed PBA power module packaging technologies and

fabricated power modules resulting in, – Decreased package thermal resistance by 30%; – Decreased package parasitic electrical inductance by 3/4th, and electric

resistance by 90%; – Reduced the major packaging manufacturing steps from five (5) to two (2); – Achieved more than 30% volume, and weight reduction.

• Benchmarked SOA automotive power module – Nissan LEAF module: electrical, thermal test, insulator sheet analysis; – Toyota Prius 2010 module: thermal, and microstructure; – Infineon HybridPack1: thermal, and microstructure; – Mitsubishi TPM II: semiconductor and package microstructure.

• Delivered customer-specific power modules, – Segmented drive inverter modules (FY12); – HDITMD inverter modules (FY11); – High power SiC diode modules (FY12); – Low inductance wire bond modules (FY11).