System and method for detecting wave aberration of photoetching projection objective

Abstract

The invention discloses a system and a method for detecting the wave aberration of a photoetching projection objective, and the system and method provided by the invention are used for photoetching machines and based on the centering of principal component fitting of space images. In the invention, an offset between the actually-measured position and nominal position of a space image is found through principal component fitting, thereby obtaining the principal component coefficient and wave aberration of the space image. The method comprises the following steps: firstly, emulating a group of space images, carrying out principal component analysis and linear regression on the space images so as to obtain principal components, a regression matrix, and a spline interpolation function of principal components and emulated space images; scanning the space images by using an X-Z plane used image sensor so as to obtain the space image distribution on the silicon wafer surface of a photoetching machine, then obtaining the offset between the actually-measured position and nominal position of the space image firstly through carrying out a centering process, and then calculating the principalcomponent coefficient corresponding to the offset; and according to the regression matrix and the principal component coefficient, fitting and solving the wave aberration by using the least square method. By using the system and method disclosed by the invention, the centering errors of the space images are compensated, and the solved repeatable accuracy is improved.

Description

technical field [0001] The invention relates to a lithography machine, in particular to a wave aberration detection system and detection method for a lithography projection objective lens based on spatial image principal component fitting and centering for a lithography machine. Background technique [0002] The projection objective lens is one of the core components of the lithography machine system. Waveform aberration in projection objectives can degrade image quality and reduce the process window, reducing yield. As the feature size of lithography continues to decrease, the aberration tolerance of the projection objective lens of the lithography machine becomes more and more stringent. The detection requirements for wave aberration of lithographic projection objective extend from low-order aberration to high-order aberration. Under this premise, it is more important to develop in-situ detection technology that can detect low-order and high-order wave aberration with hig...

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Problems solved by technology

However, this method requires strict knowledge of the coordinates of the measurement space imag

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