Photomask Pattern Size Adjustment via Coordinate Rounding and Area Scaling
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Solution Overview
Problem
In the semiconductor industry, current methods for adjusting photomask patterns during miniaturization lead to errors in critical dimension tolerance and reduced exposure resolution due to rounding of decimal places during coordinate adjustments, resulting in different sizes of original patterns after enlargement or reduction.
Innovation Solution
A method that involves coordinate conversion by multiplying corner coordinates of a photomask pattern by a scaling factor, rounding off all decimal places unconditionally, and subsequent length and width adjustments to ensure accurate size manipulation, including enlarging and reducing the pattern in stages to maintain pattern integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If coordinate conversion is performed by rounding off all decimal places, then the manipulation process is simplified, but the size accuracy of the photomask pattern deteriorates
Solution Approach 1:
The patent segments the coordinate conversion process into two distinct stages: first converting coordinates to integers by rounding, then separately calculating the scaling factor based on area relationships. This segmentation allows the simplified integer conversion to be compensated by the precise area-based scaling factor calculation, resolving the contradiction between operational simplicity and size accuracy.
Solution Approach 2:
The patent implements feedback by calculating the scaling factor based on the area relationship between the original and target photomask patterns, then using this scaling factor to adjust the coordinates. This feedback mechanism ensures that the rounded coordinates still achieve the desired size accuracy by compensating for the rounding errors through the area-based scaling calculation.
2Adaptability or versatility
If the photomask pattern is enlarged and then reduced to the required size, then the pattern can be manipulated, but the original pattern size may differ after adjustment
Solution Approach 1:
The patent performs preliminary action by first converting the photomask pattern coordinates to integers through rounding, then calculating the scaling factor based on the area relationship before final coordinate adjustment. This preliminary conversion to integers simplifies subsequent manipulation while the area-based scaling factor ensures the final pattern size remains accurate and consistent with the original pattern.
3Device complexity
If all decimal places are rounded off during coordinate adjustment, then the calculation is simplified, but the critical dimension tolerance and exposure resolution are reduced
Solution Approach 1:
The patent changes the parameter approach by introducing an area-based scaling factor that compensates for the rounding errors. Instead of directly working with rounded coordinates, the patent calculates the scaling factor based on the area relationship between original and target patterns, then applies this factor to maintain critical dimension tolerance and exposure resolution accuracy despite the simplified integer coordinate conversion.
Data Source
AI summary
A method of adjusting the size of a photomask pattern is provided. First, the original coordinate is converted. Then the length and width of the original pattern are converted. Next, the size difference caused by the coordinate conversion is corrected according to the result of the length and width conversion.