Presenter Information

Weiping Cai


Materials Science and Engineering

Research Advisor

Mattox, Douglas M.

Advisor's Department

Materials Science and Engineering


In multi-layer circuits, the reduction of the dielectric constant in substrate materials is becoming increasingly important, as the heat emission of the circuits increases with an increasing number of layers. One way to achieve a lower dielectric constant is to create porosity in the material. In this project, two types of substrate samples were made with coin-shaped porosity. One had holes of 8.0mm in diameter, and the other had holes of 2.5mm in diameter. The total vacuum area was 250mm2, or 7.7% of the total area, in either case. It was hoped to discover a relationship between aspect ratio and the effectiveness of dielectric constant reduction. But due to problems with measurements and sample size, trends were not clear, although it could be tentatively stated that the smaller porosity gave less reduction.

Document Type


Presentation Date

May 1994