Reticle Mark Arrangement for Misalignment Measurement
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Solution Overview
Problem
In semiconductor manufacturing, misalignment of upper and lower layers can lead to device performance degradation and wiring short-circuits, necessitating accurate measurement and correction of layer alignment.
Innovation Solution
The method involves arranging reticle marks in a kerf region of a reticle, calculating the area of polygons at their arrangement positions, and deciding these positions based on the calculated area to maximize coverage and minimize overlap, allowing for precise measurement and correction of misalignment between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reticle marks are arranged in the kerf region, then misalignment measurement accuracy is improved, but mark arrangement complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple candidate reticle mark arrangement patterns with their corresponding polygon areas before actual use. When marks need to be arranged, the system simply selects from these pre-prepared patterns based on the polygon area, avoiding complex real-time calculations and reducing operational complexity while maintaining measurement accuracy.
2Area of stationary object
If reticle marks are positioned to maximize polygon area, then measurement coverage is improved, but arrangement difficulty increases
Solution Approach 1:
The system performs preliminary calculations to determine optimal reticle mark arrangement patterns that maximize polygon area coverage. These optimal patterns are stored in advance, allowing the manufacturing process to simply implement the pre-determined optimal arrangement without facing the complexity of real-time optimization calculations.
Solution Approach 2:
The patent changes the parameter of polygon area as the optimization criterion for reticle mark arrangement. By focusing on maximizing the polygon area formed by connecting reticle mark positions, the system transforms a complex multi-dimensional arrangement problem into a more manageable single-parameter optimization that can be pre-calculated and stored.
3Reliability
If multiple reticle marks are arranged in the kerf region, then misalignment detection capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the kerf region into multiple discrete reticle mark positions, each contributing to the overall misalignment detection capability. By dividing the measurement function into multiple independent mark positions whose relative positions form a polygon, the system improves detection reliability while maintaining manageable manufacturing complexity through standardized mark patterns.
Data Source
AI summary
Reticle marks are arranged at a plurality of places in a kerf region of a reticle, the area of a polygon with apexes at arrangement positions of the reticle marks is calculated, and the arrangement positions of the reticle marks are decided based on results of calculation of the area of the polygon.