Digital Lithography Double Exposure for Resolution and Process Window
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Solution Overview
Problem
Existing lithography techniques face challenges in achieving improved resolutions and process windows as device sizes decrease, particularly in the manufacturing of semiconductor devices and display devices like LCDs.
Innovation Solution
A method involving double exposure patterns is employed, where a second exposure pattern is determined using rule-based or lithography model processes to enhance the intensity log-slope (ILS) and depth-of-focus of features formed in a photoresist, utilizing a maskless lithography device with virtual mask files for patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single exposure lithography is used, then the process is simple and fast, but the resolution and process window are insufficient for decreasing device sizes
Solution Approach 1:
The patent divides a single exposure process into two separate exposure steps, each with its own virtual mask file. The first exposure creates an initial pattern and the second exposure adds additional patterns, allowing complex high-resolution features to be formed through multiple simpler steps rather than requiring a single complex exposure
Solution Approach 2:
The first exposure pattern is determined and applied before the second exposure pattern. The system pre-calculates and applies the first virtual mask to establish a baseline pattern, then uses the second virtual mask to add remaining features. This preliminary action allows the more critical second exposure to be optimized based on the results of the first exposure
2Manufacturing precision
If exposure parameters are optimized for maximum intensity, then feature formation is enhanced, but the process window and depth-of-focus are reduced
Solution Approach 1:
The system determines exposure parameters for both virtual mask files based on maximizing the intensity log-slope (ILS) rather than just maximum intensity. This parameter change in the optimization criterion simultaneously improves feature formation precision while maintaining a larger process window and depth-of-focus, resolving the contradiction between precision and reliability
Data Source
AI summary
Embodiments described herein relate to methods of printing double exposure patterns in a lithography environment. The methods include determining a second exposure pattern to be exposed with a first exposure pattern in a lithography process. The second exposure pattern is determined with a rule-based process flow or a lithography model process flow.