Method for detecting pollution of contact surface of mask and mask table

Abstract

The invention provides a method for detecting pollution of a contact surface of a mask and a mask table. The method comprises steps as follows: the mask and a wafer are provided, and the mask is placed on the mask table of a photoetching machine and aligned to the wafer; S2, reference values of alignment compensation parameter of the mask are collected; S3, the steps S1 and S2 are repeated, multiple reference values of the alignment compensation parameter are collected, and an upper limit value and a lower limit value of the alignment compensation parameter are set according to the multiple collected reference values of the alignment compensation parameter; S4, the step S1 is repeated, an alignment compensation parameter value of the alignment is collected, if the alignment compensation parameter value exceeds the upper limit value or the lower limit value, the photoetching machine stops working and the mask table or the mask is cleaned, and if the alignment compensation parameter value is between the upper limit value and the lower limit value, the photoetching machine works continuously. According to the method for detecting pollution of the contact surface of the mask and the mask table, the condition of the contact surface of the mask and the mask table can be monitored in real time.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for detecting the contamination of the contact surface between a mask plate and a mask table. Background technique [0002] In the integrated circuit manufacturing process, a complete chip generally needs to go through more than ten to thirty times of photolithography. In so many times of photolithography, a mask is required. The purpose is to The pattern is transferred to the wafer. Except for the first photolithography, the photolithography of other levels must align the pattern of this level with the pattern left by the previous level before exposure. The purpose is to cover the pattern on the mask plate to the wafer with maximum precision. on an existing graph. However, during the storage of the mask plate and the transfer process of the robot arm, some pollutants may come into contact with it, which may cause the mask table to be contaminated d...

AI Technical Summary

Problems solved by technology

However, during the storage of the mask plate and the transfer process of the robot arm, some pollutants may come into contact with it, which may cause the mask table to be contaminated during the contact process with the mask plate. If the contact surface between the mask plate and the mask table is polluted , will affect the alignment accuracy of the mask and cause alignment errors; and the contamination of the contact surface between the mask and the mask table will cause the mask to be placed unevenly and out of focus, resulting in abnormal patterns in local areas. Real-time monitoring of the contamination of the contact surface between the stencil and the mask table

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