Method and system for monitoring acid concentration in etching process

Abstract

The invention discloses a method and system for monitoring the acid concentration in an etching process. The invention determines concentration values of different acids in a current etching acid solution in an etching system by acquiring the number of products currently etched in the etching system and on the basis of the number of the products and an acid concentration variation model established to represent a variation relation of concentrations of the different acids in the etching acid solution with the number of the etched products. In this way, the invention can accurately and quickly determine the concentration values of the different acids in the etching system.

Description

technical field [0001] The invention relates to a monitoring method and system for acid concentration in an etching process. Background technique [0002] In the manufacturing process of TFT, etching is an essential step, and the control of the concentration of etching acid is extremely important for the formation of gate, source, and drain etching shapes and the control of etching line width. For example, for the gate located at the bottom layer of the entire TFT substrate, the quality of the etching shape has a great influence on the growth of each layer of film in the future; for the source and drain electrodes, too high acid concentration will cause over-etching, resulting in Insufficient driving current and poor display; too low acid concentration will cause insufficient etching, resulting in reduced aperture ratio and reduced brightness and contrast. [0003] During the etching process of forming the gate and source and drain electrodes, the acid in the etching acid s...

AI Technical Summary

Problems solved by technology

However, since the online optical concentration meter is based on the absorptiometry for measurement, for the etched acid solution, the system contains a variety of etching products, and these etching products also have substances that interfere with absorption, thus making the concentration measurement value greater than Actual theoretical value

With the increase of the number of etched sheets and the extension of the life of the acid solution, the acid concentration deviation caused by the increasing etching products in the etching acid solution will become larger and larger, and the system will mistakenly think that the acid concentration is up to standard and reduce the amount of replenishment of different acids , which seriously affects the etching quality

Images