A method for reducing the deformation of silicon wafer caused by adsorption of photolithography workpiece table

Abstract

The invention discloses a method for reducing silicon wafer deformation caused by photoetching workpiece platform adsorption. The method comprises the following steps: obtaining high and low morphology distribution of the lower surface of a silicon wafer when an adsorption force does not exist through measurement, applying an adsorption force to a photoetching workpiece platform, simulating and calculating the high and low morphology distribution of the upper surface of the silicon wafer, and inspecting the distribution to ensure that the high and low morphology of the upper surface of the silicon wafer is positioned within the focusing range of the workpiece platform after adsorption and form an ideal plane as much as possible. By the method, the silicon wafer deformation caused by photoetching workpiece platform adsorption is reduced, so that the overlay error on the workpiece platform plane caused by the adsorption force is reduced and the yield of products is increased.

Description

technical field [0001] The present invention relates to a photolithography process method, in particular to a photolithography process method for supplementing the overlay accuracy of a photolithography machine. Background technique [0002] With the development of photolithography technology, higher and higher requirements are put forward for overlay precision. For ideal photolithography, the flatter the silicon wafer, the larger the process production window can be obtained, thereby improving the overlay accuracy to meet the increasingly higher process requirements such as line width critical dimensions. However, a perfect absolutely flat silicon wafer does not exist. During the production process, the process equipment deals with uneven silicon wafers. The unevenness of the silicon wafer is mainly caused by several reasons: first, the manufacturing process of the silicon wafer itself; second, the defects caused by the silicon wafer after the previous process steps, inclu...

AI Technical Summary

Problems solved by technology

[0003] During the process, the silicon wafer is adsorbed on the workpiece table. Since the workbench and the lower surface of the silicon wafer in contact with the workbench are randomly distributed with uneven areas, under the same adsorption force, different parts of the silicon wafer will produce The adsorption deformation is different, which brings about the warping of the upper surface of the silicon wafer due to the adsorption deformation, which causes some deformation points to be unable to be within the focusing range of the workpiece table through the focusing and leveling system , resulting in the vector difference of the overlay accuracy in the X and Y directions of the workpiece table plane

And the distribution of these vector differences is also random, which cannot be directly eliminated by a preset method

The impact of these differences on overlay accuracy can only be minimized by means of detection-correction

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