Temperature control method for projection objective of photoetching machine

Abstract

The invention provides a temperature control method for a projection objective of a photoetching machine, where the objective temperature is regulated to a set value of the objective temperature by use of a temperature control unit (TCU), comprising the following control steps: initializing system parameters, deciding to enter which control step: pre-regulating the TCU inner water temperature to a set value; using switch control, with the objective temperature as a master control variant, controlling the objective temperature in a target accuracy of step P2; using a cascade control arithmetic with a Smith predictor, with the objective temperature as the master control variant, using an increment PID arithmetic, and a water temperature at a flow plate as a secondary control variant, using an increment PI arithmetic for the secondary control loop; using a cascade control arithmetic without a Smith predictor, with the objective temperature as a master control variant, using an increment PI arithmetic for the master control loop, and the water temperature at the flow plate as a secondary control variant, using the increment PI arithmetic for the secondary control loop; using the increment PI arithmetic, where the control variant is the water temperature at the flow plate.

Description

technical field [0001] The invention belongs to the field of temperature control of components, and relates to a method for controlling the temperature of a projection objective lens of a photolithography machine. Background technique [0002] In the semiconductor industry, constant temperature control is required for certain critical components, such as projection objectives in photolithography machines. Due to the narrow working space of these key parts, strict requirements on the working environment and high temperature control accuracy, they cannot be directly controlled by ordinary temperature control equipment such as fans, electric heaters, and air conditioners. [0003] At present, special equipment is generally used in the industry to control the temperature of key parts by providing temperature-controlled circulating fluid to exchange heat with key parts. [0004] In the projection objective lens temperature control system, the device that provides this temperatur...

AI Technical Summary

Problems solved by technology

The process of finding the optimal water temperature in this algorithm is too long, which increases the system stabilization time

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