Substrate Warpage Detection via Oblique Light Beam
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Solution Overview
Problem
Existing substrate detachment detection devices in substrate processing apparatuses can only detect when a substrate has detached, but not when it is at risk of detachment due to warpage, leading to potential damage and defective wafers.
Innovation Solution
A substrate warpage detection device that uses a light transmitting part to obliquely transmit a light beam upward, with a light receiving part to detect the amount of received light, allowing for the detection of substrate warpage before detachment occurs by determining when the substrate protrudes above a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate detachment detection is performed using temperature difference or image pickup, then substrate detachment can be detected, but substrate warpage that may lead to detachment cannot be detected in advance
Solution Approach 1:
The light beam is positioned to pass through a region near the substrate surface before detachment occurs. When warpage causes the substrate to protrude by a predetermined height, it blocks the light beam, generating a detection signal. This allows preliminary detection of warpage conditions that may lead to detachment, enabling preventive action before actual detachment occurs.
Solution Approach 2:
A light beam is introduced as an intermediary detection medium between the substrate and the detection system. The light beam passes through a specific region near the substrate surface, and any protrusion of the substrate blocks this light, providing an indirect but effective means of detecting warpage that precedes detachment.
2Reliability
If substrate warpage detection is implemented using light beam transmission, then substrate warpage can be detected before detachment, but the device complexity increases
Solution Approach 1:
The detection function is extracted into a separate, dedicated light beam transmission system positioned beside the substrate loading region. This separates the detection mechanism from the substrate processing system, allowing independent optimization of each while reducing overall system complexity.
Solution Approach 2:
The light beam serves as a simple intermediary that requires minimal infrastructure. By using light transmission through a defined region rather than complex sensors or imaging systems, the detection mechanism remains relatively simple while effectively detecting substrate protrusion.
3Measurement precision
If the light beam passes near the substrate surface, then substrate warpage can be detected, but the risk of light beam interference with substrate processing increases
Solution Approach 1:
The light beam is positioned to pass through a specific local region near the substrate surface that is optimized for detection sensitivity. This localized approach allows high measurement precision in the detection zone while minimizing the light beam's interaction with the substrate in other critical processing regions.
Solution Approach 2:
The light beam transmission path is arranged asymmetrically relative to the substrate loading region, passing through a region near the substrate surface at an angle or position that maximizes detection capability while minimizing interference with the substrate processing operations.
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 the detection of substrate warpage during rotation, allowing for timely measures to prevent detachment and chamber damage by decelerating or stopping the rotary table when warpage is detected.
Implementation Method 1
a light transmitting part configured to transmit a light beam obliquely upward from a side of the rotary table such that a lower portion of the light beam collides with an upper end of a side surface of the rotary table and an upper portion of the light beam positioned more upward than the lower portion of the light beam passes a portion near the surface of the rotary table; and a light receiving part installed to face the light transmitting part and configured to receive the light beam passing the portion near the surface of the rotary table so as to detect an amount of received light
Data Source
AI summary
A substrate warpage detection device for detecting warpage of a substrate loaded on a substrate loading region having a recess shape formed on a rotary table along a circumferential direction during rotation of the rotary table, includes a light transmitting part configured to transmit a light beam obliquely upward from a side of the rotary table such that a lower portion of the light beam collides with an upper end of a side surface of the rotary table and an upper portion of the light beam positioned more upward than the lower portion of the light beam passes a portion near the surface of the rotary table, and a light receiving part installed to face the light transmitting part and configured to receive the light beam passing the portion near the surface of the rotary table so as to detect an amount of received light.