Power Electronics Packaging

Introduction

The power module packaging laboratory enables fast prototyping of novel power module layouts and the exploration of physical mechanisms and processes involved in power module packaging as well as embedding of relevant probes into the design. Medium voltage power module prototypes utilizing 10kV SIC MOSFETSas well as custom test samples were already demonstrated in the lab.  Continuous process optimization is being pursued and efforts will be extended in the future to implement emerging packaging materials and processes.

Special equipment

In order to ensure a high quality in the prototype manufacturing the laboratory is equipped with a wide range of  state of the art  equipment as listed below:

a1 heavy wire wedgebonder

  -  Pull & Shear test. Al wedge wirebonding for power interconnects. Modular wirebond head replaceable with pulltest or sheartest head.  Al heavy wires with Ø250-500 micron.

ultrasonic welder

  - allows ultrasonic welding of attaching robust high current Cu power terminals to the DBC hybrid circuits.

Vacuum Vapour Phasesoldering system

Vapour phase reflow soldering system. Combined with the built-in vacuum module the soldering system provides voidfree and reliable soldering of dies and DBC- baseplate stacks.

Chemical Wet stations for surface preparation, deposition and cleaning

Yellow light conditions on demand for photosensitive processes such as photoresist spincoating, development etc.

workstation for clean assembly and handling

A  dustfree laminar flow workstation for dust sensitive process steps such as solder application and die placement.

Vacuum chamber facilities

Degassing of encapsulant gels or epoxies before and after for potting of final modules to eliminate bubbles in encapsulants.  

Material sample preparation for microscopy

Diamond cutting and polishing to make sections of modules and power components (Si IGBTS, SiC MOSFETS,  GaN  HEMT etc).

Features & Services

The laboratory facilities are established with the aim of "solid prototyping" and entire prototypes or subprocesses can be tried, optimized and tested. In collaborative projects with business partners, new power module prototypes are developed, manufactured and verified based on new SiC and GaN (wide band gap) power components as well as conventional components. Ongoing activities include manufacturing and testing of power modules based on new SiC high-voltage components.

Highlights of in-house processing facilities:

•    Photolithography and etching of power substrates such as DBC (direct bonded copper).
•    High reliability soldering using state of the art multi-vacuum vapour phase reflow system.
•    Semiautomatic wire bonding.
•    High quality power terminal attachment using ultrasonic welding.
•    Non-destructive testing using scanning acoustic microscope.
•    Optical microscope inspection and material sample preparation for microscopy.
•    Clean process control utilizing clean workstation, wet benches and plasma cleaning

sponsors
 


Contact information

Associate professor Christian Uhrenfeldt
Direct phone: +45 9940 7331
E-mail: chu@et.aau.dk

location

Pontoppidanstraede 107, room 1.123