Method and system for adding reverse exposure assist feature

Abstract

The invention discloses a method for adding a reverse exposure assist feature to a semiconductor chip linear test layout, which comprises: screening out a reverse exposure assist feature addition area; classifying the reverse exposure assist feature addition area into different reverse exposure assist feature addition types based on a distance between the edge lines of the test layout; determininga parameter range of adding the reverse exposure assist feature according to an established process window OPC model; acquiring a PV-band value obtained by adding the reverse exposure assist featurebased on the OPC model as a process window size evaluation standard; adding different sizes of reverse exposure assist features to different reverse exposure assist feature addition types, in order that the layout obtained by adding the reverse exposure assist features based on a design rule conforms to the process window size evaluation standard. The method can improve the process window of the main features in various line width environments, and can avoid the defect that the addition of same parameter SRAF causes the main features in different line width environments to be unable to producethe optimal assist feature.

Description

technical field [0001] The present invention relates to the field of semiconductor manufacturing, in particular to a method for improving the resolution of a photolithography process by adding a sub-resolution exposure assistance pattern (SRAF: Sub-resolution-assist-feature) to a linear test layout of a semiconductor chip. Add method to exposure assist graph. The invention also relates to a reverse exposure auxiliary pattern addition system for improving the resolution of the photolithography process by adding sub-resolution exposure auxiliary patterns to the linear test layout of the semiconductor chip. Background technique [0002] With the continuous reduction of semiconductor manufacturing process technology nodes, sub-resolution exposure assist features (SRAF: Sub-resolution-assist-feature) are usually added to improve the resolution of the lithography process, and the depth of field (DOF, depth of focus) of the graphics , semi-dense (semi-dense) and isolated (iso) gra...

AI Technical Summary

Problems solved by technology

However, since the risk of SRAF being exposed to silicon wafers in different environments is different, adding the same parameter SRAF is not an optimal result for the main pattern in different environments, so the process window of the main pattern in each environment cannot be maximized.

In addition, when it is allowed to add a reverse exposure auxiliary pattern on the layout, it is added to the center of the layout based on rules, but the center position is not necessarily the best position for SRAF, which may result in the same size of SRAF on the silicon wafer. It was exposed on the Internet, and finally when selecting the SRAF size, it will be selected in the direction of a small size, which will weaken the effect of SRAF on the main graphics, and it is very limited to improve the process window

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