DAVID B. GRAVES
PROFESSOR OF CHEMICAL ENGINEERING

The Graves group is studying ways to minimize emissions in the semiconductor industry.

David Graves: Plasma Physics Research

 

Jud King and his wife, Jeanne, at the Tan Hall dedication.
photo by Jane Scheiber.

The move to Tan Hall from Gilman Hall resulted in a great increase in the amount and quality of space for experimental studies for the Graves group. The Graves group studies, primarily, phenomena in gaseous plasmas, especially as used in manufacturing semiconductor devices and related thin solid film devices.

Historically, the group has focused much effort on modeling and numerical simulation of plasmas, with only a limited effort experimentally. But that changed dramatically when we moved to Tan Hall. From that time, the group expanded considerably into experimental studies, and now the second or third generation of experimental Ph.D. students have completed their thesis work in Tan Hall.

Reducing Environmental Impact
Several different types of projects have been, and are continuing, in Tan Hall. One set of projects involves studies of environmental challenges in the semiconductor industry.The group has been involved in an engineering research center jointly supported by the National Science Foundation (NSF) and the Semiconductor Research Corporation (SRC) entitled: “The NSF/SRC Engineering Research Center on Environmentally Benign Semiconductor Manufacturing.” For example, the group has studied ways to avoid or minimize the emission of perfluorocarbon and hydrofluorocarbon (PFC and HFC) gases from various plasma processes.

We are currently studying the nature of by-products created in plasma etch equipment from etching various new materials such as low and high dielectric constant insulating materials, as well as etching of proposed new metallic gate electrode materials. The experimental equipment used for these studies was donated, in part, by Lam Research Corporation and IBM Research.

Plasma Surface Interactions
Another effort that expanded when we moved to Tan Hall was experimental studies of plasma-surface interactions using vacuum-beam systems. Our first system was donated by the IBM Almaden Research Center, and this system has now been used by three generations of Ph.D. students. Dr. John Coburn, retired from IBM Research, has helped greatly in defining and conducting these experiments. For example, in this system we studied the mechanisms and kinetics associated with radical-surface abstractive recombination reactions that often dominate the chemistry of halogencontaining plasma etch reactors.

More recently, studies of radical-assisted atomic layer chemical vapor deposition of thin films were made in this system. We have now built an additional vacuum-beam system, in part from equipment donated by Lam Research Corporation. This research focuses on fundamental understanding of the nature of radical-surface and ion-surface interactions, especially as applied to challenges associated with making interconnects for semiconductor devices (the so-called ‘back-end’ of the process of semiconductor device manufacture). These studies are also relevant to a general understanding of nanometer-scale control of surfaces exposed to reactive plasmas.

The Graves group uses this vacuum beam analysis system

Related sites:

Tan Hall, spring 2002 stories

David Graves research page

 

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College of Chemistry UC Berkeley

 

Tan Hall

Research in Tan Hall

Alexis T. Bell: Building Better Catalysts

Harvey Blanch: Biochemical Engineering

David Graves: Plasma Physics Research

Roya Maboudian: Semiconductor Surfaces

Susan Muller: Studying the Mechanics of Complex Fluids

Clayton Radke: Colloids and Interfaces

Angelica Stacy: Solid State Chemistry