Rim Etching Nozzle Positioning via CCD Distance Detection
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Solution Overview
Problem
Conventional substrate processing apparatuses face challenges in accurately controlling the rim etching width due to uneven substrate sizes, leading to inconsistent removal of thin films around the substrate's circumferential edge.
Innovation Solution
A substrate processing apparatus with a bevel unit and drive mechanism that allows the nozzle to move freely and adjust its distance from the substrate's edge using non-contact detection by CCDs, ensuring precise and uniform rim etching through real-time distance adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the nozzle is fixed above the rim portion of the substrate to perform etching, then the etching process can be performed, but the rim etching width cannot be controlled uniformly due to uneven substrate sizes
Solution Approach 1:
The nozzle is made movable rather than fixed, allowing it to dynamically adjust its position relative to the substrate rim. The drive mechanism enables the nozzle to move toward or away from the substrate, and the detecting element provides real-time feedback on the distance between the nozzle and substrate edge, allowing the system to adapt to variations in substrate size while maintaining uniform etching width.
Solution Approach 2:
A detecting element (such as a CCD or laser sensor) is introduced to measure the distance between the nozzle and the circumferential edge surface of the substrate in real-time. This detection signal is fed back to the control system, which adjusts the nozzle position via the drive mechanism to maintain a constant etching width despite variations in substrate diameter.
2Measurement precision
If the nozzle distance from substrate edge is not precisely controlled, then the apparatus structure is simpler, but the rim etching width accuracy deteriorates
Solution Approach 1:
The mechanical positioning system is supplemented or replaced with non-contact detection methods such as optical sensors (CCD cameras) or laser distance sensors. These detecting elements measure the distance between the nozzle and substrate edge without physical contact, providing high measurement precision while avoiding the complexity of precision mechanical positioning mechanisms.
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 precise and uniform control of the rim etching width around the substrate, preventing unnecessary film removal and enhancing processing accuracy despite variations in substrate size.
Implementation Method 1
a detecting element which performs non-contact detection of a distance between said nozzle and a circumferential edge surface of said substrate
Data Source
AI summary
A bevel unit comprises CCDs and processing liquid nozzles, and the CCDs take an image of a circumferential edge surface of a substrate. An image processing part detects the distances between the circumferential edge surface of the substrate and the processing liquid nozzles by image processing the signals from the CCDs. A control unit compares thus detected distances between the circumferential edge surface of the substrate and the processing liquid nozzles with set distances from the circumferential edge surface of the substrate to the processing liquid nozzles which are set in a recipe so as to be a desired rim etching width, and calculates an amount of displacement between the detected distances and the set distances. In accordance with the amount of displacement, the control unit activates motors and accordingly positions the bevel unit.