Tru-Si Technologies and OSE-USA Announce Joint Thin-Wafer Development Program; Goal is Higher-Yield Production of Stacked Die Assemblies

Business Wire, March 5, 2002

Business Editors/High-Tech Writers

SUNNYVALE, Calif.--(BUSINESS WIRE)--March 5, 2002

Tru-Si Technologies, Inc., and OSE-USA today announced a joint development effort to create strong, ultra-thin microchip die that can be stacked and interconnected with up to four die per package, with very high yields in volume manufacturing.

An innovator of advanced wafer-thinning processes and applications, Tru-Si will utilize its processing knowledge and proprietary equipment for dry plasma etching to produce silicon wafers that are thinned to 100 microns or less.

OSE-USA, a leading provider of advanced technology IC package assembly and manufacturing services, will develop the specialized dicing, mounting, and bonding processes for interconnecting the thinned die into conventional ball gate array (BGA) packages.

OSE-USA Vice-President of Development, Dave Tovar, said the common goal of the initiative is to demonstrate a production-ready process for stacking several die with very high yields. "However," he said, "one significant problem in building stacked assemblies today is die cracking that occurs when a larger die is laid onto a smaller die. We believe that this cracking is exacerbated by die weakness resulting from the grinding and/or polishing process used to thin wafers. By removing grinding damage we feel that we will resolve this die weakness and reduce other factors that impact the yield and limit our assembly flexibility."

According to Tru-Si CTO, Pat Halahan, other companies have announced similar efforts, but have overlooked the critical step of removing the silicon damage created by thin wafer grinding processes. "Tru-Si pioneered technology to etch away grinding and/or polishing damage, and has successfully demonstrated damage removal and wafer thinning on 200mm wafers to thicknesses as low as 50 microns," Halahan said. "Our worldwide base of installations are routinely thinning wafers, so we've gleaned a wealth of manufacturing experience to apply to delivering die with the strength necessary for stacked assemblies."

Stacked die assemblies have gained industry interest as a way to increase product functionality without increasing package size and without die redesign. By stacking the die vertically, as opposed to horizontally, as is done with multichip modules (MCMs), the product gains increased functionality and smaller size.

About Tru-Si

Headquartered in California's Silicon Valley, privately-held Tru-Si Technologies serves the global semiconductor industry with innovative solutions for damage-free wafer thinning, ultra-thin wafer handling and new chip-to-chip interconnection structures. The company's proprietary technologies for atmospheric downstream plasma (ADP) chemical dry etching and NoTouch(TM) handling, along with revolutionary through-silicon applications, enable semiconductor manufacturers to meet burgeoning demand for smaller, thinner, cheaper and more functional devices used in wireless, portable, smart-card, networking, security and Internet applications. Tru-Si's technology is used by leading chipmakers in some of the world's first high-volume ultra-thin wafer production lines. For more information about Tru-Si, visit the company online at www.trusi.com.

About OSE-USA

OSE-USA, Inc., formally know as Integrated Packaging Assembly Corporation (IPAC), one of the nation's onshore providers of advanced packaging assembly services, announced its new name in 2001 to reflect the company's strategic reorganization and association with Orient Semiconductor Electronics, Inc., of Taiwan. Located in the heart of Silicon Valley, the company's close proximity to its customers and leading packaging technology allows OSE-USA to provide dynamic, quick response, application-specific packaging solutions in QFP, LQFP, TQFP, PBGA, Chip Scale Packaging, MLP, Flip Chip, Stacked Die, System in Package, MCM, and other microelectronic packages. The assembly service is complemented with its ability to provide Quick Turn Service for above mentioned package portfolios. Recently, OSE-USA has started a design center, which allows it to design a new leadframe or substrate and assemble the package at its facilities. For more information about OSE-USA, visit the company online at www.ose-usa.com.