Lithography Detection Apparatus Alignment Offset Correction
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Solution Overview
Problem
Existing methods for aligning marks on a substrate in lithography processes face challenges in maintaining accuracy due to shifts in measurement values caused by changes in substrate orientation, which affect the alignment of exposure light and reduce throughput.
Innovation Solution
A detection apparatus that includes a stage capable of changing the substrate's position and orientation, multiple detectors, and a processor that calculates measurement offset values by inclining a reference member based on detection region and focal position information, allowing for accurate alignment of marks across different detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of alignment marks to be measured is increased to improve alignment accuracy, then measurement time increases and throughput decreases
Solution Approach 1:
The measurement process is divided into two distinct phases: a calibration phase where measurement offsets are obtained using a reference member with known mark positions, and a production phase where alignment marks on substrates are measured. This segmentation allows the system to prepare correction data in advance, enabling rapid measurement during production without compromising accuracy.
Solution Approach 2:
Measurement offset values are obtained in advance during a calibration phase using a reference member before actual substrate measurement begins. This preliminary action stores correction data that can be rapidly applied during production, eliminating the need for time-consuming recalibration and enabling high-speed alignment measurement.
2Measurement precision
If multiple mark detection systems are used to increase the number of alignment marks detected, then measurement value shifts occur due to substrate orientation changes
Solution Approach 1:
A reference member with precisely known mark positions serves as an intermediary to calibrate each mark detection system. By measuring marks on this reference member and comparing with known positions, the system obtains measurement offset values that compensate for individual detector variations and substrate orientation effects, ensuring consistent measurements across multiple detectors.
Solution Approach 2:
The system dynamically adjusts measurement values by applying correction offsets based on the relationship between substrate orientation and measurement value shifts. By changing the parameter compensation approach from fixed to dynamic (based on orientation), the system maintains measurement consistency across different substrate orientations and detector positions.
3Measurement precision
If measurement offset correction is applied without considering substrate orientation changes, then alignment accuracy decreases
Solution Approach 1:
The system establishes a feedback mechanism where substrate orientation information is used to select or adjust the appropriate measurement offset correction. By incorporating orientation as a feedback parameter, the system dynamically applies the correct correction level, ensuring accurate alignment measurements while maintaining a manageable correction process through automated orientation-based selection.
Data Source
AI summary
A detection apparatus for detecting a plurality of marks arranged on a substrate is provided. The apparatus includes a stage which supports the substrate, a plurality of detectors arranged apart from each other and configured to detect different marks of the plurality of marks arranged on the substrate, and a processor. For each of predetermined combinations of the detectors, the processor inclines a reference member supported by the stage at an inclination according to information on a position of a detection region and a focal position of each detector, and aligns a reference mark arranged on the reference member with each detector, and the processor obtains a measurement offset value of each of the plurality of detectors based on measurement values each acquired by the alignment performed for each of the plurality of predetermined combinations.