Optical Position Detection for Plasma Processing Focus Rings
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Solution Overview
Problem
Current processing apparatuses for semiconductor devices cannot accurately detect the positional relation between a target object and components like a mounting table or focus ring, leading to assembly errors and deteriorated in-plane uniformity during plasma processing.
Innovation Solution
A position detection system using a light source and multiple optical elements to emit and receive measurement light, with a control unit determining the positional relation between the focus ring and target object by scanning the emission light across the focus ring to the target object, allowing for precise positioning and wear detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the focus ring is replaced to maintain processing quality, then the focus ring wear is renewed, but assembly errors are generated and positional relation deteriorates
Solution Approach 1:
The patent replaces mechanical position detection methods with optical measurement. A measurement light source irradiates the target object and focus ring, and optical elements detect their positions and relative relationships through light reflection, eliminating the need for mechanical sensors and their associated assembly errors.
Solution Approach 2:
The patent introduces light as an intermediary to detect the positional relationship between the target object and focus ring. The measurement light reflects off both components, and optical elements measure their positions relative to each other, providing a non-contact method to detect assembly errors after focus ring replacement.
2Productivity
If the target object is mounted on the mounting table, then processing can be performed, but the positional relation between the target object and mounting table cannot be detected
Solution Approach 1:
The patent replaces mechanical position detection with optical measurement. The measurement light source and optical elements form an optical system that detects the position of the target object on the mounting table without mechanical contact, enabling accurate position detection during processing operations.
3Manufacturing precision
If a focus ring is provided to improve in-plane uniformity, then processing uniformity is improved, but the focus ring wears and requires replacement
Solution Approach 1:
The patent implements a feedback mechanism where the measurement light source and optical elements continuously monitor the position and condition of the focus ring during processing. This allows detection of focus ring wear and position changes, enabling timely replacement or adjustment to maintain processing uniformity.
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 accurate detection of the target object's position and wear on components, ensuring consistent in-plane uniformity and reducing assembly errors in plasma processing.
Implementation Method 1
a light source configured to generate measurement light; three or more optical elements configured to emit the measurement light generated by the light source as emission light
Implementation Method 2
three or more optical elements configured to emit the measurement light generated by the light source as emission light and receive reflected light
Data Source
AI summary
There is provided a position detection system for use in a processing apparatus including a mounting table configured to mount thereon a disc-shaped target object and a focus ring surrounding a periphery of the mounting table. The system includes a light source configured to generate measurement light, three or more optical elements configured to emit the measurement light as emission light and receive reflected light, a driving unit configured to move each of the optical elements such that a scanning range from the focus ring to the target object is scanned, and a control unit configured to obtain positional relation between the focus ring and the target object based on the reflected light in the scanning range of each of the optical elements.