OPC Method
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Solution Overview
Problem
Existing Optical Proximity Correction (OPC) methods face challenges in maintaining the critical dimension and corner-to-corner space of patterns during lithography, leading to off-target defects and process window issues, especially in dense stagger patterns like the via layer, where corner-to-corner spaces are small and mask rule constraints are frequently violated.
Innovation Solution
The proposed OPC method involves split processing of selected patterns to divide each side into corner and middle splits, allowing for separate corrections in each iteration of model-based OPC, ensuring that corner dimensions and area requirements are met without violating mask rule constraints, thereby adjusting the corner-to-corner space and increasing the pattern area to achieve on-target results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If model-based OPC is performed on dense stagger patterns with small corner-to-corner space, then the pattern contour can be corrected to match target, but the corner-to-corner space violates mask rule constraints
Solution Approach 1:
The patent segments the pattern correction process into two independent stages: corner correction and area correction. Corner correction adjusts the corner-to-corner space to meet mask rule constraints, while area correction adjusts the pattern area to achieve target contour accuracy. This segmentation allows each stage to optimize one parameter without compromising the other, resolving the contradiction between contour accuracy and mask rule compliance.
Solution Approach 2:
The patent performs corner correction as a preliminary action before area correction. By first adjusting the corner-to-corner space to satisfy mask rule constraints, the foundation is laid for subsequent area correction to achieve target contour accuracy without violating manufacturing constraints. This preliminary action ensures that subsequent corrections operate within acceptable parameter ranges.
2Manufacturing precision
If OPC correction moves pattern edges to achieve target contour, then the pattern area increases, but the corner-to-corner space decreases violating MRC
Solution Approach 1:
The patent divides the OPC correction into two independent correction processes: corner correction that adjusts corner-to-corner space while maintaining area, and area correction that adjusts pattern area while maintaining corner-to-corner space. This segmentation allows each correction to optimize its specific parameter without adversely affecting the other, resolving the contradiction between area accuracy and corner-to-corner space maintenance.
Solution Approach 2:
The patent applies different correction strategies to different parts of the pattern: corner regions are corrected to maintain corner-to-corner space, while the central area is corrected to achieve target area and contour accuracy. This local differentiation allows each region to be optimized for its specific function without compromising overall pattern integrity or violating mask rules.
3Reliability
If mask minimum resolution dimension is set strictly to avoid open and short defects, then the process window narrows, but pattern fidelity is maintained
Solution Approach 1:
The patent segments the correction process into corner correction and area correction, allowing corner-to-corner space to be independently optimized to meet mask minimum resolution constraints while area correction independently optimizes pattern fidelity. This segmentation enables the process to navigate narrow process windows by addressing different parameters separately, maintaining defect prevention while preserving pattern accuracy.
Solution Approach 2:
The patent changes the correction parameters in a specific sequence: first adjusting corner position parameters to satisfy mask rules, then adjusting area parameters to achieve target fidelity. This parameter change strategy allows the process to adapt to strict minimum resolution requirements while maintaining pattern accuracy through controlled, sequential parameter optimization.
Data Source
AI summary
The present application discloses an OPC method, which includes: step 1: providing an initial target layer and setting a mask minimum resolution dimension; step 2: selecting a first pattern that will violate a mask rule check in subsequent MBOPC from the initial target layer; step 3: performing split processing on the first pattern to divide each side of the first pattern into a plurality of splits including corner splits and a middle split, the initial target layer after split processing being a second target layer; and step 4: performing MBOPC based on the second target layer and obtaining a mask pattern layer, the corner splits and the middle splits being corrected separately, the corner dimension of the first pattern in the mask pattern layer being controlled through the corner splits, the area of the first pattern in the mask pattern layer being controlled through the middle split.