Photomask Pattern Measurement Area Segmentation
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Solution Overview
Problem
In the manufacturing process of semiconductor photomasks, it is challenging to accurately set and measure the dimension of patterns, particularly for OPC patterns with complex shapes, due to difficulties in selecting a suitable measurement area that avoids corner portions and ensures precise measurement.
Innovation Solution
A pattern measurement method and system that involves obtaining a standard pattern, specifying a measurement point, and setting a measurement area including two straight line segments on both sides of the measurement point, while excluding areas near corner portions, to measure the dimension between contours of the scanned image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the measurement area is set to include the entire pattern, then the measurement can capture the full pattern structure, but the measurement precision deteriorates due to the influence of corner portions and pattern complexity
Solution Approach 1:
The pattern measurement area is segmented into multiple sub-areas, specifically selecting regions that contain straight line segments while excluding corner portions. This segmentation allows the measurement to focus on specific linear features of the pattern rather than the entire complex structure, thereby improving measurement precision for dimensional characteristics.
Solution Approach 2:
Different regions of the pattern are treated differently based on their suitability for measurement. Areas containing straight line segments are selected for measurement, while corner portions and regions with complex curved features are excluded. This local quality approach ensures that measurement precision is optimized by focusing on regions with well-defined linear characteristics.
2Measurement precision
If the measurement area is set to avoid corner portions, then the measurement precision improves by eliminating corner roundness influence, but the device complexity increases due to the need for precise measurement area selection algorithms
Solution Approach 1:
The measurement area selection is performed as a preliminary action before the actual dimension measurement. By pre-identifying and selecting regions containing straight line segments while excluding corner portions, the system prepares the measurement data in advance, ensuring that subsequent measurements are performed on optimal regions. This preliminary action simplifies the overall measurement process while maintaining high precision.
Solution Approach 2:
The system automatically identifies and selects appropriate measurement areas based on the pattern structure itself, without requiring manual intervention or complex external algorithms. The measurement area selection is performed self-service by the system analyzing the scanned image features and automatically determining regions suitable for measurement, thereby reducing operational complexity.
3Ease of operation
If the measurement area is set for simple patterns, then the ease of operation improves, but the adaptability deteriorates when measuring complex OPC patterns
Solution Approach 1:
The measurement system is designed with universality to handle multiple pattern types, including simple patterns and complex OPC patterns. By implementing a general algorithm that can automatically identify straight line segments and select appropriate measurement areas regardless of pattern complexity, the system achieves multi-functionality. This allows the same measurement procedure to be applied universally across different pattern types, maintaining ease of operation while improving adaptability.
Data Source
AI summary
Easily and correctly measuring a dimension of a pattern of a photomask or of an OPC pattern of the photomask.A pattern measurement method of the present invention includes steps of obtaining both a standard pattern corresponding to a predetermined pattern and a measurement point specified in advance; setting a measurement area so that it includes two straight line segments on both sides of the measurement point among outlines of the standard pattern; and measuring a dimension between two contours of the scanned image of the predetermined pattern in the measurement area by superposing the measurement area on the scanned image of the predetermined pattern. The measurement area is set so as not to include portions near corner portions connected to two line segments.