Dual Optical System Mark Detection for Alignment Precision
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Solution Overview
Problem
Existing exposure apparatuses face challenges in accurately detecting the position of alignment marks on substrates due to the characteristics of the marks and measurement light, leading to inefficiencies in alignment operations during device pattern transfer.
Innovation Solution
A mark detection apparatus is developed, comprising a first optical system that emits measurement light, a second optical system that deflects and aligns light components, and a light receiver that captures diffracted light, enabling precise detection of alignment marks by utilizing zeroth-order and diffracted light components across multiple wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single optical system is used to detect alignment marks, then the device complexity is low, but the measurement precision is insufficient due to characteristics of the alignment mark and measurement light
Solution Approach 1:
The optical system is divided into a first optical system for emitting measurement light and a second optical system for deflecting and receiving light. This segmentation allows each optical system to be optimized for its specific function, improving measurement precision while managing overall system complexity through functional decomposition.
Solution Approach 2:
The second optical system acts as an intermediary between the first optical system and the alignment mark. It receives diffracted light from the mark and deflects it to the light receiver, enabling precise detection without requiring the first optical system to directly handle all detection functions.
2Adaptability or versatility
If multiple light components with different wavelengths are used, then the adaptability to different alignment mark characteristics is improved, but the device complexity increases due to multiple optical paths
Solution Approach 1:
The second optical system is designed to handle multiple light components with different wavelengths through a unified diffracted light receiving path. This multi-functional design allows the system to detect alignment marks with different characteristics using the same optical infrastructure, improving adaptability without proportionally increasing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the accuracy and efficiency of alignment operations by effectively detecting alignment marks, even when they have different wavelengths, thereby improving the precision of device pattern transfer on substrates.
Implementation Method 1
a second measurement light including at least one part of a zeroth-order light and a diffracted light generated by an irradiation of the first measurement light to the mark area
Implementation Method 2
a second optical system that is configured to deflect a second measurement light including at least one part of a zeroth-order light and a diffracted light generated by an irradiation of the first measurement light to the mark area
Implementation Method 3
a light receiver that is configured to optically receive a fourth measurement light including at least one part of a zeroth-order light and a diffracted light generated by an irradiation of the third measurement light to the mark area
Data Source
AI summary
A mark detection apparatus is configured to detect a mark formed in a mark area of an object and has: a first optical system configured to emit a first measurement light to the mark area; a second optical system configured to irradiate the mark area with at least one part of a zeroth-order light and a diffracted light generated by an irradiation to the mark area from the first optical system; and a light receiver that configured to optically receive at least one part of a zeroth-order light and a diffracted light generated by an irradiation to the mark area from the second optical system.