TI turns to pillar flip-chip for 45-/40nm node

Texas Instruments Inc. announced it will no longer use traditional wirebonding techniques for devices at the 45-/40nm node and below, as the workhorse chip-packaging technology is fast running out of gas for leading-edge designs.

TI will continue to use wirebonding for devices above 45-/40nm. But for those nodes and below, TI is embracing an emerging technology called fine-pitch copper pillar flip-chip packages. The company is jointly working with IC-packaging specialist Amkor Technology Inc. as part of a long-term collaboration in the arena.

To move down the process path, the industry mainly talks about chip scaling and integration. "As an industry, we've over-integrated," said Tom Thorpe, VP and manager of external development and manufacturing at TI.

To enable next-generation designs, chip-packaging is now playing a more critical role in the IC flow, Thorpe said. Technologies like fine-pitch copper pillar flip-chip packages will enable a new class of application processors, DSPs and power management devices, he added.

In fact, for some time, TI has quietly been shipping chips based on pillar flip-chip. "The OMAP device is a standalone applications processor and does not include a baseband, and TI only began shipping an OMAP product based on copper pillar flip-chip earlier this year," according to a TI spokeswoman.

For decades, though, IC makers like TI have used cost-effective and workhorse wirebonders for use in packaging. Chipmakers will continue to use wirebonders for the foreseeable future, but these systems are hitting the wall at the leading-edge, possibly at the 45nm node.

One of the ongoing problems is that wirebonding tends to stress and damage the low-k dielectric interconnects in leading-edge IC designs. There are also performance issues with packages using wirebonders.

As a result, TI and other chipmakers are looking at alternative packaging techniques. In fact, it has been widely known for about two years that TI is moving away from wirebonders for leading-edge designs only, he said. "At 45nm, we won't use anymore wirebonders," he said. TI will continue to use wirebonders for parts at above 45nm, it was noted.