Dynamic thermal model and control performance analysis over frequency domain of temperature control unit

Abstract

The temperature control unit (TCU) is widely used in lithography tools or other precision equipment to achieve a high level of temperature stability. Still, there is no systematic analysis of the thermal model in the present study about how to build a precise TCU. In this paper, we provide a new perspective for analyzing the outlet temperature performance of TCU. We analyzed the thermal model of TCU’s sub-devices and thermal model of environmental disturbance over the frequency domain, then obtained the influence of different processes on the TCU output temperature at different frequencies. The above thermal models are brought into two commonly used process control frameworks to comprehensively consider the temperature control effect under the combination of control and hardware. The relationship expressions from the temperature spectrum performance to the fluctuation index are derived to obtain the quantitative TCU temperature performance. We built a TCU experimental platform with the water medium and verified the accuracy of TCU thermal models, thermal disturbance models, and the accuracy of temperature fluctuation index derivation, all within a 5% error. The TCU temperature accuracy reaches ± 1mk under one sigma statistics as a thermal engineering application case.

Keywords

• Temperature control unit (TCU)
• Thermal model
• Frequency domain
• Temperature stability