Surface Position Detection Using Splitter and Combiner
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional surface position detecting apparatuses in lithography processes face challenges in accurately measuring substrate positions due to measurement errors caused by environmental disturbances and optical system variations, leading to reduced throughput and accuracy.
Innovation Solution
A surface position detecting apparatus that uses a light-sending optical system and a light-receiving optical system with a splitter and combiner to independently detect measurement light and reference light, allowing for accurate detection of substrate position deviations without requiring a separate measuring system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate measuring system is used to measure measurement errors, then measurement accuracy is improved, but throughput is reduced due to additional measurement time
Solution Approach 1:
The patent combines the measurement error measuring function with the existing surface position detection optical system by using a beam splitter to separate measurement light and reference light. This allows both functions to be performed simultaneously using the same optical path, eliminating the need for a separate measuring system and avoiding throughput reduction.
Solution Approach 2:
The patent enables continuous measurement of both surface position and measurement errors simultaneously using the optical system. By using a beam splitter to divide the light into measurement light (passing through the objective lens) and reference light (bypassing the objective lens), both measurements occur continuously without sequential operation, maintaining high throughput.
2Measurement precision
If a separate measuring system is used to measure measurement errors, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the measurement error measuring function into the existing surface position detection system by using a beam splitter. This approach uses the same objective lens and optical path for both measurement light and reference light, avoiding the need for additional separate optical systems and reducing overall device complexity.
Solution Approach 2:
The optical system is designed to perform multiple functions: the objective lens serves both for surface position detection (measurement light) and for providing a reference path (reference light). The beam splitter enables the system to simultaneously perform surface position measurement and measurement error detection using the same optical components, enhancing multi-functionality without increasing complexity.
3Measurement precision
If measurement light and reference light share the same optical path, then measurement accuracy is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent uses a beam splitter to segment the light into two separate paths: measurement light that passes through the objective lens and reference light that bypasses it. This segmentation allows independent detection of each light type while maintaining the benefits of shared optical path components, simplifying the detection process.
Solution Approach 2:
The beam splitter acts as an intermediary device that separates measurement light and reference light while allowing both to originate from the same source and share common optical components. This intermediary enables clean separation of the two light paths for independent detection, reducing the difficulty of measuring and detecting each type of light accurately.
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
Enables quick and accurate detection of measurement errors, improving the throughput and accuracy of the lithography process by correcting for deviations using reference light detection, thereby maintaining high precision in substrate positioning.
Implementation Method 1
a light-sending optical system to guide light to a detection target surface; a light-receiving optical system to guide the light to a light-receiving surface
Implementation Method 2
a splitter which splits the light guided to the detection target surface, into measurement light and reference light on a field basis
Implementation Method 3
a combiner which combines the measurement light traveling via the detection target surface toward the light-receiving optical system, with the reference light traveling toward the light-receiving optical system without passing via the detection target surface, on a field basis
Implementation Method 4
a detector arranged on the light-receiving surface; the detector independently detects the reference light and the measurement light on the light-receiving surface
Data Source
AI summary
A surface position detecting apparatus disclosed herein has a light-sending optical system SL to guide light to a detection target surface, a light-receiving optical system to guide the light to a light-receiving surface, a detector arranged on the light-receiving surface, a splitter to split the light guided to the detection target surface W, into measurement light and reference light on a field basis, and a combiner to combine the measurement light traveling via the detection target surface W toward the light-receiving optical system, with the reference light traveling toward the light-receiving optical system without passing via the detection target surface W, on a field basis; and the detector independently detects the reference light and the measurement light on the light-receiving surface.