Substrate Alignment Using Relative Mark Measurement Across Layers
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Solution Overview
Problem
Current methods for correcting substrate distortions during device manufacturing require dedicated detection optical systems, which are costly and impractical to mount on exposure apparatuses, especially as device complexity increases and the number of hard masks grows, reducing alignment mark detectability due to decreased light transmittance.
Innovation Solution
A processing system comprising a measurement apparatus and an exposure apparatus, where the measurement apparatus detects the relative position between alignment marks in different layers, allowing the exposure apparatus to align and process substrates without needing high-accuracy detection of marks in the target layer, using a high-accuracy detection optical system to measure the relative position between first and second structures on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated detection optical system is used to detect alignment marks through hard masks, then alignment accuracy is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent introduces a measurement apparatus as an intermediary device that separately measures the positions of alignment marks before the exposure process. This intermediary measurement system avoids the need to modify the exposure apparatus's detection optical system, thereby maintaining alignment accuracy while preventing complexity increase in the main exposure device.
Solution Approach 2:
The patent performs alignment mark position measurement in advance using the measurement apparatus, before the actual exposure process. By obtaining alignment mark positions preliminarily, the system can correct substrate distortion without requiring the exposure apparatus to have complex real-time detection capabilities during exposure.
2Reliability
If multiple hard masks are used to increase etching resistance, then device reliability is improved, but light transmittance decreases making alignment mark detection difficult
Solution Approach 1:
The measurement apparatus serves as an intermediary that can detect alignment marks under optimized conditions separate from the exposure process. This allows alignment mark detection to be performed when multiple hard masks are present, overcoming the transmittance issue by using a dedicated measurement system rather than relying on the exposure apparatus's detection capabilities.
Solution Approach 2:
The patent replaces the optical detection method (relying on light transmittance through hard masks) with a separate measurement system that can detect alignment marks regardless of the number of hard masks. This substitution eliminates the trade-off between etching resistance and detectability by using a different detection approach.
3Manufacturing precision
If overlay inspection marks are used instead of alignment marks, then section region shape correction becomes possible, but a dedicated detection optical system is required
Solution Approach 1:
The measurement apparatus acts as an intermediary that can detect both alignment marks and overlay inspection marks with high precision. By using this separate measurement system, the patent enables section region shape correction through overlay inspection marks without requiring the exposure apparatus to have dedicated detection optical systems for these specialized marks.
Data Source
AI summary
The present invention provides a processing system that includes a first apparatus and a second apparatus, and processes a substrate, wherein the first apparatus includes a first measurement unit configured to detect a first structure and a second structure different from the first structure provided on the substrate, and measure a relative position between the first structure and the second structure, and the second apparatus includes an obtainment unit configured to obtain the relative position measured by the first measurement unit, a second measurement unit configured to detect the second structure and measure a position of the second structure, and a control unit configured to obtain a position of the first structure based on the relative position obtained by the obtainment unit and the position of the second structure measured by the second measurement unit.