Method for calibrating focal planes of OPC and PWOPC models

Abstract

The invention discloses a method for calibrating focal planes of OPC and PWOPC models. The method comprises the following steps: collecting ID structure graphic line width measurement data on FEM wafers; forming a standard super line width measurement data formatted file; selecting out graphic data with high sensitivity to the focal distance; acquiring a focal plane after Poisson symmetry treatment; extracting every group of image plane and focal plane values after Poisson symmetry treatment and analyzing data to obtain a Poisson symmetry curve of an image plane-focal plane, and carrying out polynomial fitting calculation on a data trend line to obtain a function expression of an image plane and a focal plane; and calibrating the focal planes of OPC and PWOPC models by using a mathematicalrelationship, which is obtained by fitting, of the image plane and the focal plane which meet the Poisson symmetry relation. Prediction accuracy of the size of a process window under conditions of different exposure energy and focusing planes on the OPC and PWOPC models and sensitivity to change of process parameters can be ensured.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuits, in particular to a method for calibrating the focal plane of OPC (Optical Proximity Correction, optical proximity effect correction) and PWOPC (Process Window Optical Proximity Correction, non-nominal condition optical proximity effect correction) models. Background technique [0002] In the advanced semiconductor manufacturing process, the increasingly narrow process window has become a big challenge for the photolithography process. Correcting the design layout with a standard OPC model based on linewidth measurement data collected under standard exposure energy and focal plane conditions can only guarantee the accuracy of the standard conditions, but when the conditions change, the model cannot be made. accurate forecast. At this time, if the design layout of the product is very sensitive to process conditions, even if the established model is very accurate, it is difficult to...

AI Technical Summary

Problems solved by technology

Correcting the design layout with a standard OPC model based on linewidth measurement data collected under standard exposure energy and focal plane conditions can only guarantee the accuracy of the standard conditions, but when the conditions change, the model cannot be made. accurate prediction

At this time, if the design layout of the product is very sensitive to the process conditions, even if the established model is very accurate, it is difficult to apply it to mass production, because the process parameters in production will always fluctuate to a certain extent

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