General Competition (December 1992)

Low Dielectric Foams for Microelectronics Applications

Sponsor: IBM Corporation, Almaden Research Center

• Project Performance Period: 3/1/1993 - 2/28/1996
• Total project (est.): $4,783,751.00
• Requested ATP funds: $1,830,929.00

The long-term trend in microcircuits to get smaller, denser, and faster with each generation is approaching some serious roadblocks. One is the need for improved electrical insulating materials. The speed of a signal pulse in a conductor is partially a function of the properties of the insulator around it, in particular the insulator's dielectric constant -- the lower the dielectric constant, the faster the pulse propagates. Increased switching speeds in microcircuits and denser packing of circuits both require conductor lines to be moved closer and closer together. But the conductors have to be far enough apart to avoid inducing signals in each other -- so-called "cross-talk" -- which also depends on how low the dielectric constant of the insulator can be pushed. Vacuum is the ideal insulator, and air is almost as good, but neither is particularly practical for commercial devices. For real applications, the designer wants a low-density material which is able to withstand the high processing temperatures associated with the manufacture of devices, and has a thermal expansion coefficient close to that of the substrate. IBM has developed some organic polymers with carefully controlled structures that meet the needs for insulators in current-generation devices but are inadequate for the systems predicted to emerge in the next decade. For those devices, IBM proposes to develop unique polymer insulating foams with dielectric constants below 2, and thermal and mechanical properties equivalent to the best current polymer insulators. The new foams would have closed-cell pores on a molecular scale. IBM proposes three possible routes for producing these novel "nano-foams", and will evaluate each thoroughly. IBM will collaborate with the Virginia Polytechnic Institute, Exfluor Research, and Sandia National Laboratory in carrying out the research and, if successful, plans to transfer the technology to U.S. vendors.

For project information:

Michael Ross, (408) 927-1283

ATP Project Manager

Michael Schen, (301) 975-6741
michael.schen@nist.gov