Fundamental Knowledge Thrust: High Density Integration (HDI)
Leader: J. Daan van Wyk, Virginia Tech
The goal of the HDI thrust is to develop packaging technologies for integrating all the functions in a power electronic converter into modules. The research work in HDI is clustered into three areas: 1) Process technology integration; 2) Module integration technology for designable lifetime; 3) Functional integration of electromagnetic, switching, structural and thermal functions in a power processor module. CPES has been promoting the idea of replacing the conventional wirebond with direct bonding, and has introduced a number of techniques, such as the flip-chip-on-flex and the embedded power technology, as shown in the figure below.
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A lead-free die-attach solution using low-temperature sintering
of nanoscale metal paste for high-performance and high-temperature
interconnection of semiconductor devices. |
In 2002, industry followed suit and came out with a range of products
that eliminate wirebond, including Fairchild’s bottomless
and BGA packaging, Hitachi’s lead-free packaging (LFPAK),
International Rectifier’s FlipFet and DirectFET, Siliconix’s
PowerPAK, and STMicroelectronics FLAT package. In addition, CPES
has developed technology for integrating electromagnetic power
passives. The figure below shows a passive IPEM that includes four
capacitors, two inductors and one power transformer. Functional
and process
integration with improved thermal management were successfully
demonstrated for the first time.
Recently, CPES made a major advance in integrating EMI filters
into a low profile, small volume integrated power electronics module
(IPEM) with characteristics superior to an EMI filter constructed
from discrete components, based on transmission line principles.
This filter has already been shown to be effective between
1 MHz and 100 MHz for filtering both common mode and differential
mode interference—a range where parasitics are already killing
performance of other filters. This new technology will greatly
simplify high frequency interference filters, reduce volume and
profile, improve manufacturability, and match perfectly with the
planar active IPEM technology (Embedded Power) developed by CPES,
as shown in the figure below, where the integrated filter is packaged
together with an active IPEM.
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Passive IPEM vs. discrete components |
Integrated filter packaged with active IPEM |