Infrared Sensor Substrate Polishing End Point Detection
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Solution Overview
Problem
Current semiconductor substrate polishing technologies, particularly those using optical sensors, require a separate window for visible light and are limited to transparent dielectric films, making them inefficient for detecting the polishing end point and stabilizing production in miniaturized, multi-layered semiconductor manufacturing.
Innovation Solution
A substrate polishing system utilizing an infrared sensor embedded within the platen to measure substrate temperature, eliminating the need for a separate window and enabling detection of the polishing end point through a look-up table correlating temperature and polishing amount, applicable to various thin film materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical sensor using visible light is used to detect polishing end point, then polishing end point detection can be performed, but a separate window for penetrating the polishing pad is required and the method is limited to transparent dielectric films
Solution Approach 1:
The patent replaces the optical sensor system with visible light with an infrared sensor system. Infrared radiation can penetrate the polishing pad directly without requiring a separate window, thereby simplifying the device structure while maintaining polishing end point detection capability. The infrared sensor detects thermal radiation from the substrate, providing measurement precision comparable to optical methods without the structural complexities of window integration.
Solution Approach 2:
The patent changes the detection parameter from visible light reflection (optical sensor) to infrared thermal radiation detection. This parameter change allows the sensing mechanism to work through the polishing pad material itself, eliminating the need for a separate window and expanding applicability beyond transparent dielectric films to various film types including metals and conductive materials.
2Adaptability or versatility
If an optical sensor is used for polishing end point detection, then detection can be performed, but the method is limited to transparent dielectric films only
Solution Approach 1:
The infrared sensor system replaces the optical sensor system, enabling detection across all film types including metals, conductors, and dielectrics. Infrared radiation penetrates the polishing pad and interacts with the substrate regardless of the film's optical transparency, thereby universality while maintaining reliable polishing end point detection for stable manufacturing processes.
3Measurement precision
If visible light is used as light source in optical sensor, then polishing end point can be detected through thin film interference, but a separate window for penetrating the polishing pad is required
Solution Approach 1:
The patent substitutes the visible light optical sensor system with an infrared sensor system that detects thermal radiation. This substitution eliminates the need for a separate window structure to penetrate the polishing pad, as infrared radiation naturally passes through the pad material. The system achieves comparable measurement precision for polishing end point detection while significantly simplifying manufacturing implementation.
4Adaptability or versatility
If infrared sensor is used to measure substrate temperature, then polishing end point can be determined without separate window and for various film types, but temperature measurement through polishing pad must be accurate
Solution Approach 1:
The patent uses the polishing pad itself as an intermediary medium that allows infrared radiation to pass through to reach the substrate. The pad material is selected or designed to be transparent or semi-transparent to infrared wavelengths, enabling accurate temperature measurement of the substrate while maintaining versatility across different film types. This intermediary approach resolves the contradiction between measurement accuracy and broad applicability.
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 solution allows for precise determination of substrate thickness and polishing end point without a separate window, enhancing precision and applicability across different film types, thereby stabilizing and improving the polishing process in semiconductor manufacturing.
Implementation Method 1
an infrared sensor located inside the platen and configured to measure a temperature of the substrate by passing infrared rays through the polishing pad
Data Source
AI summary
Provided is a high-precision substrate polishing system. An apparatus for polishing a substrate includes a platen on which a polishing pad is seated and which is rotatable, a substrate carrier configured to grip a substrate and rotatable on an upper side of the platen, an infrared sensor located inside the platen and configured to measure a temperature of the substrate, and a controller configured to determine a polishing state of the substrate using a value measured by the infrared sensor.