Wafer Overlay Measurement Map Configuration via Selective Inspection Marks
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Solution Overview
Problem
Existing methods for measuring overlay accuracy on wafers are time-consuming and reduce production capacity, as they often require a full measurement map that is not comprehensive when only a portion of inspection marks are randomly selected.
Innovation Solution
A method and apparatus for configuring a measurement map that selects a second set of inspection marks based on preset rules to achieve comprehensive overlay accuracy measurement with reduced measurement, using a first inspection result to determine target inspection marks for a more efficient measurement map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full measurement map is used to measure overlay accuracy, then measurement comprehensiveness is improved, but measurement time increases and production capacity decreases
Solution Approach 1:
The full measurement map is segmented into multiple measurement maps through division into first measurement map data and second measurement map data. The inspection marks are divided into first inspection marks and second inspection marks, allowing selective measurement on different wafer regions (center vs. edge) to achieve comprehensive coverage while reducing time per measurement cycle
Solution Approach 2:
The measurement map configuration is made dynamic by determining whether to use the first or second measurement map based on wafer type (center wafer vs. edge wafer). This dynamic selection allows the system to adapt the measurement approach to specific wafer positions, optimizing both comprehensiveness and efficiency for different measurement scenarios
2Productivity
If a portion of inspection marks is randomly selected to save time, then measurement time is reduced, but measurement comprehensiveness deteriorates
Solution Approach 1:
Different measurement strategies are applied to different local regions of the wafer. The first measurement map focuses on center region inspection marks while the second measurement map focuses on edge region inspection marks. This local quality approach ensures that each region is measured with appropriate marks, maintaining comprehensiveness while reducing overall measurement time
Solution Approach 2:
Instead of measuring all inspection marks (excessive action), the system performs partial measurement by selecting only the necessary first or second measurement map based on wafer type. This partial action approach measures only the relevant inspection marks for each wafer region, achieving sufficient comprehensiveness without the burden of complete measurement
Data Source
AI summary
Embodiments of this invention provide a measurement map configuration method and apparatus. A wafer to be inspected is provided. The wafer includes a plurality of inspection marks. A first inspection result is obtained based on a first set of inspection marks. A second set of inspection marks is selected based on a preset rule. The second set of inspection marks is less than the first set of inspection marks. A second inspection result is obtained based on the second set of inspection marks. If an overlay accuracy of the second inspection result matches an overlay accuracy the first inspection result, a measurement map for the wafer is set based on target inspection marks. The target inspection marks are the second set of inspection marks of the measurement map.