Multi-System Mark Detection with Rotatable Stage Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exposure apparatuses face challenges in achieving high overlay accuracy and throughput due to placement errors of substrates on stages, which affect the alignment of marks detected by multiple position detection systems, leading to degraded detection accuracy and increased detection time.
Innovation Solution
A detection apparatus that utilizes a stage capable of rotation, combined with multiple detection systems, performs initial detection at a first rotation angle and subsequent detection at a second angle, calculating differences in detection values to correct for placement errors, thereby enabling accurate and efficient alignment mark detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple position detection systems are used to detect multiple marks simultaneously, then throughput is improved, but measurement precision deteriorates due to stage rotation errors
Solution Approach 1:
The patent replaces mechanical alignment methods with optical field-based detection. By using the optical fields of multiple position detection systems to define a rotation reference, the system eliminates the need for mechanical reference marks and achieves rotation error correction through optical measurement rather than mechanical positioning.
Solution Approach 2:
The patent introduces an intermediary reference system formed by the optical fields of multiple position detection systems. These optical fields serve as a mediator to establish a common rotation reference that all detection systems can use, enabling coordinated measurement without direct mechanical connection between systems.
2Manufacturing precision
If the number of marks to be detected is increased to improve overlay accuracy, then manufacturing precision is improved, but detection time increases
Solution Approach 1:
The patent enables continuous detection of multiple marks by multiple position detection systems simultaneously. By establishing a common rotation reference, all systems can operate continuously without sequential adjustment, maintaining constant detection throughput while processing an increased number of marks.
Solution Approach 2:
The patent performs preliminary establishment of the rotation reference using the optical fields of position detection systems before mark detection begins. This preliminary action creates a stable reference framework that enables subsequent rapid, continuous detection of multiple marks without time-consuming adjustments.
3Measurement precision
If offset calibration is performed using a reference mark to reduce adjustment error, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical offset calibration procedures with an optical field-based reference system. By using the inherent optical fields of position detection systems as the reference, the system eliminates the need for separate mechanical reference marks and calibration mechanisms, reducing overall device complexity.
Data Source
AI summary
A detection apparatus including a plurality of detection systems arranged spaced apart from each other so as to detect, of a plurality of marks provided on an object held by a stage, marks different from each other, and a processing unit configured to perform a first process of obtaining a first detection value by detecting the plurality of marks by one or more detection systems in a first state in which the stage is arranged at a first rotation angle, and a second process of obtaining a second detection value by detecting the plurality of marks by two or more detection systems in a second state in which the stage is arranged at a second rotation angle, and obtain a difference between the first detection value and the second detection value for each of the plurality of marks.