Photomask Linewidth Control via Exposure Adjustment
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Solution Overview
Problem
In substrate processing for electronic device manufacturing, there is a challenge in maintaining consistent pattern linewidth after etching, particularly between isolated and dense patterns on photomasks, due to variations in resist image profiles and exposure conditions, leading to unevenness and reduced precision at the nanometer level.
Innovation Solution
A method is developed to predict device linewidth characteristics based on the sharp-edged feature of projected images, allowing for adjustment of exposure conditions to ensure desired linewidths in resist patterns, thereby maintaining consistency and precision across patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resist image linewidth is adjusted to compensate for pattern collapse, then the linewidth variation between isolated and dense patterns is reduced, but the exposure process becomes more complex
Solution Approach 1:
The patent employs parameter changes by modifying the resist image linewidth parameter differently for isolated and dense patterns. The first linewidth for isolated patterns is set larger than the second linewidth for dense patterns. This parameter adjustment is based on the different collapse characteristics of the two pattern types during curing, allowing the final etched linewidth to be uniform across both pattern types while managing the exposure process complexity through systematic parameter differentiation.
2Manufacturing precision
If higher precision in processing size is required at the nanometer level, then the yield and operation speed of devices are improved, but the unevenness and variation in finished dimension become more critical
Solution Approach 1:
The patent addresses dimensional uniformity by applying local quality principles to the resist image formation process. Different linewidth parameters are used for isolated and dense patterns to account for their different collapse behaviors during curing. This localized adjustment ensures that both pattern types achieve the same final linewidth precision, thereby maintaining high dimensional uniformity across the entire wafer and improving both yield and operation speed.
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
This approach enables the formation of patterns with consistent linewidths, reducing unevenness and variation in finished device sizes, improving yield and operation speed in electronic device manufacturing.
Implementation Method 1
a patterning process of a resist on a substrate by exposure
Data Source
AI summary
A device linewidth characteristic is predicted based on a sharp-edged feature of a projected image of a predetermined pattern (steps 104 to 110), and an exposure condition of the pattern is adjusted based on the device linewidth characteristic that has been predicted (step 112). Then, exposure is performed under the adjusted exposure condition. That is, patterning of a resist on a substrate is performed with the projected image of the pattern (step 114). And, by developing the substrate after patterning, a resist pattern that satisfies a desired device linewidth characteristic is formed on the substrate. Accordingly, by performing etching of the substrate with the resist pattern serving as a mask, a pattern after etching can be formed with a desired linewidth.