IITC: an IC interconnect conference reflects a changing reality in semiconductor process development

A change in program at the International Interconnect Technology Conference this year gives an interesting insight into how the division of labor in the process integration community has changed. And that in turn reflects a coming change in the nature of the participants in the IC physical design flow.

The program change in itself sounds quite minor. The conference this year will include, for the first time in a long while, papers on unit-process technology in addition to the usual fair of papers on interconnect structures and strategies.

The change, according to IITC 2008 Publicity Chair, and Chief Technologist for 3D Development at IBM Michael Shapiro, reflects attendee feedback that in addition to information about the wonderful multi-layer interconnect structures, attendees want detailed information about the individual process steps used to create the structures. “An example is the Bosch etch process. It’s been widely used in forming MEMS structures, but has never really been used for interconnect. Now, with the growing interest in 3D interconnect systems, people are looking for ways to create very deep vias—and they want to know the gritty details of the Bosch etch process step.”

The underlying change here involves intellectual property. There was a time when the details of a unit process—the equipment, consumables, and recipe–would have been a trade secret. But as Shapiro pointed out in a conversation this afternoon, that is no longer so much the case. “These days, most of the basic process development work is done by the equipment manufacturers, not the process integration engineers,” Shapiro reflected. “So a lot of what might once have been trade-secret information is now pre-competitive information—developed by the equipment manufacturer for use by all their customers. If there are secrets, they lie in the way the customers tweak the unit process, not in the basics.”

The notion that most of the how-to information about unit processes can be in the public domain is an interesting one. It does not imply that all processes are becoming standardized, Shapiro was quick to point out. But it does mean that all processes phases using a common equipment set have a great deal in common. And that in turn means the goal of being able to move a physical design from one process to another with a reasonable amount of effort may be getting closer to reality. If porting the design means just having to deal with the foundry-specific tweaks, with the underlying platform well understood and public, design porting becomes a much more constrained problem. It also, interestingly, becomes a problem requiring significant input from the equipment manufacturers as well as the foundry process engineers. Look for this change in the partnership of people who produce final physical designs, coming to a project near you.