Dynamic Template Alignment for Semiconductor Substrate Positioning
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Solution Overview
Problem
Existing alignment methods for semiconductor manufacturing face challenges in maintaining accuracy due to variations in the shape of alignment marks or three-dimensional structures on substrates, leading to reduced position measurement precision when using automatically generated templates across different substrates.
Innovation Solution
An alignment apparatus and method that involves creating a template from a device pattern on a substrate, extracting feature points, and adjusting the Z position or tilt of the substrate stage to optimize correlation between the template and the substrate's image, ensuring accurate alignment by maximizing the correlation degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a template automatically generated from a target pattern on one substrate is used for pattern matching on another substrate, then the alignment process can be automated, but the correlation degree decreases due to shape variations in the target pattern across different substrates
Solution Approach 1:
The patent applies dynamics by making the template adaptable rather than fixed. The template is automatically adjusted to match the actual shape of the alignment mark on each substrate, allowing the system to adapt to shape variations while maintaining automation. This resolves the contradiction by enabling the template to dynamically conform to different substrate characteristics without manual intervention.
Solution Approach 2:
The patent changes the parameters of the template based on the detected shape of the alignment mark. By extracting shape information from the captured image and using this to generate or adjust the template parameters, the system maintains high correlation degrees across substrates with varying shapes. This parameter adaptation allows automated processing while preserving measurement precision.
2Adaptability or versatility
If the shape of the alignment mark or three-dimensional structure varies on different substrates, then manufacturing flexibility is improved, but the position measurement accuracy using fixed templates decreases
Solution Approach 1:
The patent implements feedback by detecting the actual shape of the alignment mark from captured images and using this information to generate or adjust templates. This closed-loop approach allows the system to adapt to shape variations in real-time, maintaining measurement accuracy while accommodating manufacturing flexibility. The feedback mechanism ensures that templates accurately represent the actual substrate features.
Solution Approach 2:
The patent performs preliminary actions by capturing images of alignment marks and extracting shape information before final template generation. This preliminary extraction of shape data allows the template to be pre-adjusted to match the specific substrate, ensuring high correlation degrees are achieved before the actual alignment measurement takes place.
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 approach enables precise alignment of substrates despite shape variations, improving alignment accuracy and reducing errors by dynamically adjusting the relative positional relationship, including height and tilt, to achieve a higher correlation degree.
Implementation Method 1
imaging an alignment mark by a camera having a storage-type photoelectric conversion element
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The alignment apparatus performs alignment of an object in a first direction along a surface of the object, based on a position of a predetermined target formed on the surface, and includes a holding unit that holds the object to be moved, an acquisition unit that acquires an image of the predetermined target formed on the surface of the object held by the holding unit, and a controller that drives the holding unit to realize a relative distance between the object and the acquisition unit in a second direction perpendicular to the surface of the object, a relative tilt between the object and the acquisition unit, or the distance and the tilt, the distance and the tilt being determined based on a correlation degree between the image acquired by the acquisition unit and a template, and detects a position of the predetermined target in the first direction based on the correlation degree.