NER: Silicon Insert Molded Plastics (SIMP)

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The objective of this research is to develop a process for injection molding polymer parts with sub-micron three-dimensional features, such as angled planes, using a process we call Silicon Insert Molded Plastics (SIMP). It is hypothesized that silicon inserts can be manufactured using microfabrication techniques allowing for tolerances, smoothness, and dimensions at a nanoscale level. In particular, advantage would be taken of silicon's ability to be selectively etched for low cost with KOH to obtain nanometer smooth <111> planes at an inclination angle of 54.7 degrees from the vertical (for a common <100> wafer), There are a host of precision products from surgical tools to fiber optic couplers that can be created with the <111> planes, and in particular, the availability of planes and edges with nanometer precision can revolutionize the way small precision parts are designed. Research into the SIMP process will progress in four areas. The first area is the design and fabrication of the silicon inserts. While microfabrication processes are becoming standardized, many concerns must be addressed for each new part, especially for features such as cooling passages or KOH etched features combined with DRIE features. The second area of research must account for the integration of the silicon inserts into a metal mold carrier that is then inserted into the molding machine. For example, thermal effects on the silicon inserts are a major concern for processing of the polymer, mold lifetime and accuracy issues. The third research area investigates the material processing aspects of nanoscale features in polymers. Specifically, the issues to address are the determination of the limits of moldable features and the discovery of techniques to improve the processability of the polymers. The final research area encompasses the design of parts to allow for easier molding of any nanoscale features. Undergraduate and graduate students will be working closely with our industrial partners -- Bayer Corp. (Polymers Division), Schick, and Teradyne Connection Systems - to help develop the SIMP process thus ensuring rapid transfer of the technology to industry.