MEMS in Thermal Processing

A joint project between Tufts University's Thermal Analysis of Materials Processing Laboratory (TAMPL) and Northeastern University's Microfabrication Laboratory sponsored by the National Science Foundation under grant number DMI-9612058.  Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

PROJECT SUMMARY

The focus of the proposed research is the investigation of the microscale radiation effects during thermal processing of electronic materials. These effects play a significant role in materials processing when the wavelength of radiation is of the same order of magnitude as the layer/film thicknesses or feature sizes of the material processed. This is an important area of materials processing for the industrial sectors since structures such as diodes, transistors, and memory devices are affected by these phenomena during fabrication. As these devices become smaller and smaller, these issues become increasingly critical to the future of electronic materials manufacturing. The microscale heat transfer effects are pertinent to thermal processing of microelectronic devices which requires careful control of the temperature distribution of the wafer. Thermal problems lead to defect generation and propagation in the material, excessive diffusion of microelectronic features, and non-uniform film deposition.

The investigators propose to create a set of simulations and experimental tools and techniques to examine the unexplored microscale radiative phenomena and to create a novel temperature and stress measurement system. For studying the microscale radiation effects, the research will combine elements from thin film optics, optoelectronics, and radiative heat transfer to identify phenomena not explored previously. For the experimental component of the study of the microscale radiative effects, the investigators will take a unique approach and use Micro-Electro-Mechanical Systems (MEMS). MEMS are based on techniques developed in the semiconductor industry to create extremely small gears, motors, pressure sensors, and other devices. These small devices range from the millimeter scale down to the micron scale; moreover, these devices are three dimensional and some are even free standing. In the proposed project, MEMS will be used to fabricate three dimensional structures that are similar to microelectronic devices. More importantly, the structures will be created to isolate the microscale radiative effects. In addition, the investigation will focus on an important electronic material processing technique used by U.S. industry, Rapid Thermal Processing (RTP), which is currently challenged by such effects.

Specifically, the project will generate the following tangible deliverables:

· A numerical simulation computational package that can determine the radiative properties of complex sub-micron devices that is undergoing any thermal process.

· A numerical simulation of RTP that accounts for sub-micron patterned wafers

· A wafer design with MEMS that provides an easy and useful way of identifying maximal temperature and stress non-uniformities in any thermal processor.

This is a collaborative project between Tufts University's Thermal Analysis of Materials Processing Laboratory and Northeastern University's Microfabrication Laboratory, combining expertise in computational microscale heat transfer, materials processing, and microfabrication.