Mask assembly and overlay measurement method

Abstract

The invention provides a mask assembly and an overlay measurement method. The overlay measurement method comprises the steps of providing a first mask and a wafer, wherein a zero mark pattern and a first mark pattern are formed in the first mask, and the first mask pattern is arranged near to the zero mark pattern; etching a zero mark and a first mark on the wafer according to the first mask; providing a second mask, wherein a second mark pattern is formed at a position of an internal region, corresponding to the first mark, of the second mask, and the second mark pattern is coincided with a center of the first mark; forming a second mark in the first mark according to the second mask; and measuring position deviation of the second mark relative to the first mark. By the overlay measurement method, a deep-N well ion injection process and an active region etching process can be conveniently overlaid and measured; different types of products can use the same mask; and compared with the prior art, the overlay measurement method has the advantages that the number of masks can be greatly reduced, and the production cost is further reduced.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a mask component and an alignment measurement method. Background technique [0002] In the existing semiconductor process, the first layer process of many products is a deep N well (DNW) ion implantation process to form a deep N well in the wafer. The specific steps of the deep N well ion implantation process are: first , coating a photoresist layer on the surface of the wafer; then, using a photolithography process to pattern the photoresist layer to form openings in the photoresist layer corresponding to the deep N wells to be formed subsequently pattern; then, perform N-type ion implantation on the wafer according to the photoresist layer, so as to form the deep N well in the wafer; finally, lift off the photoresist layer. [0003] After the deep N well ion implantation, the photoresist layer used to define the deep N well will be stripped, which will lead to the su...

AI Technical Summary

Problems solved by technology

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a mask assembly and an alignment measurement method for solving the problem of low alignment measurement accuracy in the prior art and the need for different types of products The problem of increased production costs caused by different masks

Images