OPC correction method based on photoetching process window

Abstract

The invention discloses an OPC correction method based on a photoetching process window. When the margin position error of a pattern is calculated, the method uses different photoetching model weights for different patterns in a photoetching layout according to a photomask error reinforcement factor, a light intensity maximum value, a light intensity minimum value and slope of a pattern measuring point. The method sets variable weights to patterns by determining the pattern characteristics and the pattern environment in the layout, and prevents the OPC correction error caused by the changes of the photoetching pattern.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to an OPC correction method based on a photolithography process window. Background technique [0002] At present, Optical Proximity Correction (OPC, Optical Proximity Correction) technology, as a resolution enhancement technology (RET, Resolution Enhancement Technology), has been widely used in key layer processes above 0.13 μm technology node. However, with the shrinking of the size of the semiconductor process, the design rules of the graphics are getting smaller and more complex. How to cooperate with the photolithography process to expand the process window is becoming more and more an OPC process. research direction. [0003] At present, the common OPC correction method is model-based OPC (Model Based OPC), which is a lithography model based on the original data of the OPC model obtained when the lithography process achieves the best conditions. E...

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Problems solved by technology

For each graph corrected by OPC, the objective function EPE final The value of the weight of each lithography model in is the same, that is, a specific constant, which causes a lot of trouble to the value of the weight

Because on the one hand, at the edge of the lithography process window, the stability of the lithography pattern is relatively poor, and the change of the critical dimension CD (Critical Dimension, critical dimension) is relatively large. In a statistical sense, 3Sigma is relatively large, that is, The original data of the collected OPC model has a relatively large variation range, so it is necessary to reduce the value of the weight; however, on the other hand, in order to judge the EPE more accurately final range, it is necessary to increase the weight value as much as possible, which brings difficulties to the value of the weight, and the credibility of the OPC model established in this way will be relatively low, resulting in OPC correction based on the lithography process window, in some Larger errors are introduced in the correction of the graphics, resulting in severe distortion of the corrected graphics

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