Microwave and Radio Frequency Rapid Electromagnetic Induction Heating (EMIH) of Silicon Wafers

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The need to reduce the thermal budgets (time, temperature) of next generation semiconductor device processing has created a significant interest in short-term rapid thermal processing (RTP) of silicon. One of the most important applications for RTP is the formation of the source and drain regions of CMOS gate stacks. Another application is the bonding of wafers for fabrication of micromechanical and power microelectronic devices. This proposal requests support for basic research of microwave and radio frequency (RF) rapid electromagnetic induction heating (EMIH) of Si. EMIH would provide valuable and unique capabilities for wafer bonding. Moreover, EMIH may be the only viable method to anneal ultrashallow implanted impurity dopant regions to the specifications required to manufacture the next generation of high density VLSI integrated circuits (the so-called 100 nm technology node). The research program involves investigations of rapid microwave and RF EMIH of Si wafers. For example, initial data indicate that EMIH spike-annealing of ultra-shallow boron-implanted wafers is superior to conventional lamp RTP. Experiments with ultra-shallow boron-implanted wafers are proposed to establish just how effective EMIH RTP can be, and to elucidate the unconventional mechanisms responsible for the observed superior performance. Similarly, initial results indicate that EMIH enables very rapid wafer bonding without the need for intermediate glue layers. The research will more thoroughly determine the quality of the bond, the minimum time and temperature required to obtain a good bond, the prospects for multi-level wafer stack bonding, and the mechanisms that explain how uniformly strong bonds are obtained during RF EMIH, even with significant radial temperature gradients. Supporting collaborations with leading semiconductor fabrication industrial organizations will provide critical input to experimental design and results analysis, and valuable mentorship of students. These collaborations will also leverage grant resources by providing sources of ultrashallow implanted wafers and post-anneal characterization from institutions with unparalleled experience and expertise in this technology area.