Design and Implementation of a Lithography Chamber Environment Controller Based on Decoupling of Temperature and Humidity

Abstract

Lithography, as the cornerstone of semiconductor manufacturing, imposes stringent tolerances on the temperature and humidity of the exposure chamber. However, the strong coupling between these two variables makes conventional PID control inadequate. To address this issue, we propose a decoupling-oriented environmental controller for the lithography chamber. First, by analyzing the internal heat- and mass-transfer mechanisms, a two-input/two-output transfer-function model of the chamber is established. A feedforward compensator is then designed to generate pre-feedback decoupling signals, which are further refined by a Hebb-rule neural-network decoupler to actively cancel cross-interference between the temperature and humidity loops. The hardware is built around an STM32F407 microcontroller and integrates auxiliary heating, refrigeration, and humidification modules. The software architecture comprises a main scheduler, data-acquisition service, and environmental-factor control kernels. Experimental results show that the controller maintains the chamber temperature within 23 ± 0.13 °C and relative humidity between 54 % RH and 57 % RH, satisfying the accuracy and dynamic-response requirements of mainstream lithographic processes.