Bruce W. Peuse

Advances in Rtp Temperature Measurement and Control

This paper reviews work to develop and improve the temperature measurement and control technology of a commercial rapid thermal processing (RTP) system. A description of the main features of this system is given, which includes a concentric multi-zone lamp heating source, multi-point temperature measurement system and real time wafer temperature control. Innovations in RTP optical thermometry are described which resulted in improved low temperature performance, a real time spectral emissivity measurement tool which enables emissivity independent temperature measurement and an improved temperature calibration capability. The multi-input multi-output (MIMO) optimal wafer temperature control methodology is discussed. Process results demonstrating an equivalent process temperature performance of 4°C, 3-sigma, all-points-all-wafers will be presented.

In-situ temperature control for RTP via thermal expansion measurement

A new method of temperature control for rapid thermal processing of silicon wafers is presented whereby in-situ wafer temperature is determined by measurement of wafer thermal expansion via a laser autofocus mechanism. Various potential error sources are considered including wafer bow, effects of wafer doping and crystal orientation. Results are provided showing that variations in crystalline orientation and dopant levels have no measurable effect on expansion of the silicon substrate, allowing a direct correlation of wafer expansion to temperature. The expansion measurement technique and implementation into a rapid thermal processing system as a temperature control is described. Preliminary data show the wafer to wafer repeatability of temperature is 1% (3-(sigma) ) using wafer expansion as the control.

In-Situ Temperature Control for Rtp Via Thermal Expansion Measurement

A new method of temperature control for rapid thermal processing of silicon wafers is presented whereby in-situ wafer temperature is determined by measurement of wafer thermal expansion via an optical micrometer mechanism. The expansion measurement technique and its implementation into a rapid thermal processing system for temperature control are described. Preliminary data show the wafer to wafer temperature repeatability to be 1% (3-σ) using this technique.

Rapid themal processing using in-situ wafer thermal expansion measurement for temperature control

An emissivity independent method of temperature control for rapid thermal processing of silicon wafers is demonstrated. In-situ wafer temperature is determined by measurement of wafer thermal expansion via a laser autofocus mechanism. A closed loop temperature control system based on this technique is integrated into a commercial rapid thermal processor with fully automatic wafer handling capability. A preliminary test using a titanium silicidation process were performed using wafer expansion thermometry. The results of this test demonstrate that this technique can provide improved wafer to wafer process repeatability.