Alignment method of lithography machine

Abstract

The invention discloses an alignment method of a lithography machine, which comprises a two-stage alignment method. A first stage is similar to the prior method and is wafer normal region alignment for obtaining 6 parameters of a wafer alignment model 1: Tx1, Ty1, Ex1, Ey1, Rotaion1 and Ortho1; and the second stage is wafer twisted region alignment for obtaining 6 parameters of a wafer alignment model 2: Tx2, Ty2, Ex2, Ey2, Rotaion2 and Ortho2. The lithography machine respectively regulates exposure forms according to two groups of different parameters. In consideration of the special wafer deformation state of the twisted region, the method is capable of subjecting the place to registration correction so as to obtain a satisfactory registration precision.

Description

technical field [0001] The invention relates to a semiconductor manufacturing process method, in particular to a photolithography machine alignment method. Background technique [0002] The wafer is processed layer by layer through a series of steps. In order for the device to work properly, the registration between layers must be within a certain range of accuracy. As the line width becomes smaller and smaller, the registration accuracy requirements become more and more stringent. In the semiconductor production process, the registration between layers is realized by the alignment of the photolithography machine. The principle is: when processing the first layer, set some alignment marks at specific positions of the exposure unit, and after processing, each layer The optical lithography machine measures the coordinates of several alignment marks left on the first layer, then fits out the wafer alignment model, and then exposes it. This model is used to reflect the wafer de...

AI Technical Summary

Problems solved by technology

[0003] When the current lithography machine alignment method is used, this model will exclude the exposure units whose coordinates deviate from this model to a certain extent (that is, the wafer deformation state and the overall difference here are relatively large), so this exposure unit will be lead to misregistration

However, during the processing of the wafer, due to process reasons (especially high temperature heat treatment), the stress inside the wafer will inevitably lead to local distortion

Therefore, under the existing lithography machine alignment method, the distortion of this area will not be considered, which will inevitably lead to poor registration between layers

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