Alignment Mark Layout for Multi-Area Wafer Overlay Detection
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Solution Overview
Problem
Current lithography processes for micro-device manufacturing face challenges in achieving precise overlay accuracy between layers due to limitations in existing alignment detection systems, particularly with movable alignment detection systems being costly and restrictive in design.
Innovation Solution
A method for providing layout information to arrange multiple marks using a mark detection system with multiple detection areas, where the pitches and sizes of marks are calculated based on specific formulas to optimize alignment without decreasing throughput, allowing for flexible and cost-effective alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a movable alignment detection system is used to detect multiple alignment marks, then the ability to cope with various shot maps is improved, but the device complexity and cost increase
Solution Approach 1:
The alignment detection system is divided into multiple fixed detection areas (first detection area, second detection area, third detection area) that are spatially separated. Each detection area has dedicated alignment sensors, eliminating the need for a single movable detection system while maintaining the ability to detect multiple alignment marks across different shot maps.
Solution Approach 2:
The multiple fixed detection areas are designed to collectively handle various shot map configurations. By strategically positioning detection areas and sensors, the system achieves universal adaptability to different shot maps without requiring mechanical movement or reconfiguration, thus reducing device complexity while maintaining versatility.
2Manufacturing precision
If more alignment marks are detected to improve wafer alignment precision, then the manufacturing precision is improved, but the device complexity and cost increase
Solution Approach 1:
The wafer surface is divided into multiple shot areas, each with its own detection area and alignment sensors. This segmentation allows simultaneous detection of multiple alignment marks across different shot areas, improving overall alignment precision without requiring a single complex detection system.
Solution Approach 2:
Multiple detection areas and their respective alignment sensors are integrated into a unified detection system. The control unit coordinates all sensors to simultaneously detect alignment marks across multiple shot areas, achieving high alignment precision through combined detection capability rather than through a single complex movable system.
3Productivity
If multiple detection areas are used to detect multiple alignment marks simultaneously, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The detection system is segmented into multiple independent detection areas with dedicated sensors. This allows parallel detection of alignment marks in different shot areas simultaneously, increasing throughput without requiring complex mechanical movement mechanisms.
Solution Approach 2:
The system replaces mechanical movement (movable alignment detection system) with a fixed multi-area detection architecture. By using multiple stationary detection areas with coordinated sensors, the system achieves high-speed simultaneous detection of multiple marks, improving productivity while reducing mechanical complexity.
Data Source
AI summary
A determination apparatus has a calculation section, where first and second direction pitches intersecting within a predetermined plane of a plurality of detection areas are D1 and D2, respectively, sizes in the first and second directions of each of a plurality of divided areas arranged two-dimensionally along the first and second directions on a substrate are W1 and W2, respectively, and first and second direction pitches of a plurality of marks arranged on the substrate are p1 and p2, respectively, calculates pitch p1 and pitch p2 of the plurality of marks that satisfy formulas (a) and (b) below, based on pitch D1, pitch D2, size W1, and size W2.p1=D1/i (i denotes a natural number)=W1/m (m denotes a natural number) (a)p2=D2/j (j denotes a natural number)=W2/n (n denotes a natural number) (b)