Semiconductor Mask Pattern Optical Proximity Correction
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Solution Overview
Problem
Current photolithography techniques face challenges in accurately transferring mask patterns onto photoresists due to the optical proximity effect, resulting in distorted shapes, such as rounded corners and disconnected patterns, when mask patterns intersect at right angles.
Innovation Solution
A mask design featuring first and second main patterns spaced apart at a cross point, with a third main pattern overlapping the cross point and auxiliary patterns around the third main pattern, which are not adjacent to the first and second main patterns, to minimize the optical proximity effect and maintain the original shape of the mask pattern during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography technique is used to transfer mask pattern onto photoresist, then pattern formation is achieved, but optical proximity effect causes shape distortion at pattern edges
Solution Approach 1:
The mask pattern is divided into multiple segments: main patterns for the primary structure and auxiliary patterns positioned at specific locations. The auxiliary patterns are segmented and placed around the cross point area to counteract the optical proximity effect locally, while the main patterns maintain the desired final pattern shape. This segmentation allows different parts of the mask to serve different functions in compensating for optical distortions.
Solution Approach 2:
The mask design implements local quality by placing auxiliary patterns specifically at the cross point region where optical proximity effects are most problematic. The auxiliary patterns have different characteristics (positioning, size, density) compared to the main patterns, tailored to address the local optical distortion issues at pattern intersections while leaving other areas unchanged.
2Manufacturing precision
If mask patterns are spaced apart to reduce optical proximity effect, then shape distortion is reduced, but pattern connectivity and structural integrity may be compromised
Solution Approach 1:
The auxiliary patterns are positioned in advance at the cross point area before the final pattern formation. These preliminary patterns serve to pre-compensate for the optical proximity effects that will occur during exposure, ensuring that the main patterns remain connected and structurally intact while achieving accurate shape transfer. The auxiliary patterns are strategically placed to maintain connectivity of the main patterns.
3Manufacturing precision
If auxiliary patterns are added to compensate for optical proximity effect, then pattern transfer accuracy is improved, but mask complexity increases
Solution Approach 1:
The solution extracts only the essential auxiliary patterns needed to compensate for optical proximity effects, rather than adding comprehensive modifications throughout the entire mask. The auxiliary patterns are selectively placed only at critical cross point regions where optical distortions occur, removing unnecessary complexity from non-critical areas while maintaining pattern transfer accuracy where it matters most.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed mask design effectively transfers the mask pattern onto the photoresist with minimal distortion, achieving a closer match to the desired shape, such as an inverted L or T shape, with reduced rounding and dent formation at the corners.
Implementation Method 1
transferring a pattern formed on the mask (to be referred to as a mask pattern hereinafter) onto the photoresist by exposing the photoresist to light using a mask
Data Source
AI summary
A mask for forming patterns of a semiconductor device is provided. The mask includes first and second main patterns disposed to be spaced apart from each other about a cross point and extending in first and second directions different from each other, a third main pattern disposed spaced apart from the first and second main patterns while being disposed between the first and second main patterns so as to overlap the cross point, and at least one auxiliary pattern spaced apart from the third main pattern in the periphery of a portion of the third main pattern, which is not adjacent with the first and second main patterns.