Photomask Block Cutting Lines for Side Lobe Suppression
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Solution Overview
Problem
Current resolution enhancement technologies (RET) in semiconductor manufacturing are prone to side lobe formation during lithography, which is not effectively addressed by existing optical proximity correction (OPC) methods, leading to inefficiencies and increased turn around time (TAT).
Innovation Solution
A photomask design incorporating multiple blocks with cutting lines passing through their centers, determined by a side lobe-related table, to suppress side lobes, combined with optical proximity correction (OPC) to compensate for lithography errors, reducing layout design restrictions and TAT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resolution enhancement technology (RET) is used to improve lithography resolution, then manufacturing precision is improved, but side lobe formation occurs causing harmful effects
Solution Approach 1:
The patent divides the photomask pattern into multiple blocks and introduces cutting lines within these blocks to segment the continuous pattern. This segmentation approach modifies the optical diffraction characteristics to suppress side lobe formation while preserving the main pattern integrity, thereby resolving the contradiction between achieving high resolution and avoiding side lobe artifacts.
Solution Approach 2:
The patent applies different treatments to different regions of the photomask pattern by identifying specific blocks that require cutting lines based on local pattern characteristics. Rather than uniformly treating the entire pattern, the method selectively applies cutting lines to blocks where side lobe formation is detected, optimizing the balance between resolution enhancement and side lobe suppression.
2Manufacturing precision
If optical proximity correction (OPC) is applied to compensate lithography errors, then manufacturing precision is improved, but turn around time increases reducing productivity
Solution Approach 1:
The patent performs preliminary identification of blocks requiring cutting lines using a side lobe related table before the full OPC process. This preliminary action filters and prioritizes pattern blocks that are most likely to form side lobes, allowing the subsequent OPC process to focus computational resources only on critical areas rather than processing the entire pattern uniformly, thereby reducing overall turn around time.
Solution Approach 2:
The patent changes the approach from traditional full-pattern OPC to a selective cutting line insertion method based on block dimensions and pattern characteristics. By using a side lobe related table to identify critical blocks and applying cutting lines only where necessary, the method transforms the OPC process from a computationally intensive full-pattern operation to a more efficient targeted intervention, reducing productivity loss.
Data Source
AI summary
A photomask for semiconductor manufacturing includes multiple first blocks and multiple second blocks. A line width and a space of the first blocks fall outside a predetermined range, and a combination of the line width and the space of the second blocks in a direction falls within the predetermined ranges. In each of the second blocks, at least one cutting line is included. The cutting line passes through a center point of the each of the second blocks to eliminate the possibility of side lobe formation.