Mask Pattern Data Verification for Resist Collapse Prevention
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Solution Overview
Problem
Conventional lithography compliance checks (LCC) fail to verify the slope of collapsed resist patterns, leading to poor formation of resist patterns, as they only average optical images in the resist film thickness direction, making it difficult to accurately determine the quality of mask pattern data before photomask manufacturing.
Innovation Solution
A method involving a mask pattern data verification apparatus that calculates optical images at designated resist film thickness positions, extracts feature quantities related to resist pattern shapes, and determines pattern failures, allowing for correction of mask pattern data to prevent pattern failures such as collapse, shorting, film reduction, and footing during resist pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If optical image is averaged in resist film thickness direction, then calculation complexity is reduced, but measurement precision of resist pattern slope is degraded
Solution Approach 1:
The resist film thickness direction is divided into multiple discrete height positions. Optical images are calculated and extracted at each height position separately, then the slopes between adjacent height positions are determined. This segmentation allows precise measurement of resist pattern slope at different depths without requiring complex full-volume averaging calculations.
2Ease of manufacture
If conventional LCC is used, then manufacturing process is simple, but reliability of resist pattern formation verification is degraded
Solution Approach 1:
The verification process transitions from two-dimensional top-view dimension measurement to three-dimensional verification by calculating optical images at multiple height positions within the resist film thickness direction. This enables detection of slope and collapse issues that cannot be detected by conventional top-view averaging methods.
3Productivity
If mask pattern data is not verified in advance, then productivity is improved, but manufacturing precision of resist pattern is degraded
Solution Approach 1:
Mask pattern data undergoes preliminary verification through lithography compliance check before photomask manufacturing. The system calculates optical images at multiple height positions, extracts feature quantities, and determines pass/fail status in advance, ensuring only verified pattern data proceeds to manufacturing, thereby preventing defective resist patterns without delaying the production schedule.
Data Source
AI summary
According to an embodiment, a pattern data generation method is provided. In the pattern data generation method, when a resist on a substrate is exposed using a mask, an optical image at a designated resist film thickness position is calculated using a mask pattern. Feature quantity related to a shape of a resist pattern at the resist film thickness position is extracted, based on the optical image. Also, whether the resist pattern is failed is determined, based on the feature quantity, and pattern data of a mask pattern determined as failed is corrected.