CMP Apparatus Optical Switching for Film Thickness Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing CMP apparatuses face challenges in increasing measurement resolution and accuracy due to the limited installation area, which is exacerbated by the size of spectrometers used for optical sensors, leading to reduced productivity in semiconductor production.
Innovation Solution
A polishing apparatus configuration that includes multiple sensor heads with a single spectrometer and a switcher, allowing selective connection of sensor heads to the spectrometer only when they face the substrate, reducing the overall size and improving measurement resolution without increasing the apparatus's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of sensor heads is increased to improve measurement resolution, then measurement precision is improved, but device complexity and apparatus size increase
Solution Approach 1:
A single spectrometer is designed to process signals from multiple sensor heads by sequentially receiving signals from different regions (center and peripheral edge portions) of the substrate. This multi-functional design allows one spectrometer to replace what would traditionally require multiple spectrometers, reducing device complexity while maintaining the capability to measure film thickness across the entire substrate surface with high resolution
Solution Approach 2:
The polishing table rotates periodically, enabling the single spectrometer to sequentially access different sensor heads positioned at different locations. This periodic rotation allows the system to collect film thickness data from multiple measurement points across the substrate in a time-multiplexed manner, achieving comprehensive measurement coverage without requiring all sensors to be connected simultaneously
2Measurement precision
If the number of spectrometers is increased to process signals from multiple sensor heads, then measurement precision is improved, but the apparatus size increases
Solution Approach 1:
The single spectrometer serves multiple functions by processing signals from both center-region sensor heads and peripheral edge portion sensor heads. This universal design eliminates the need for separate spectrometers for different measurement zones, significantly reducing the apparatus footprint while maintaining accurate film thickness measurement capability across the entire substrate
Solution Approach 2:
The patent merges the signal processing function for multiple sensor heads into a single spectrometer. By combining what would be separate measurement systems into one integrated spectrometer, the apparatus achieves compact size while preserving the ability to perform comprehensive film thickness measurements across different substrate regions
3Measurement precision
If multiple sensor heads are connected to multiple spectrometers, then measurement precision is improved, but productivity deteriorates due to increased apparatus size
Solution Approach 1:
The single spectrometer is designed to handle signals from multiple sensor heads that monitor different regions of the substrate simultaneously. This universal processing capability enables comprehensive film thickness measurement across the entire substrate surface, improving measurement precision while maintaining a compact apparatus size that supports high productivity in semiconductor manufacturing
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 configuration enhances measurement resolution and accuracy while maintaining a compact apparatus size, improving productivity by efficiently processing signals from multiple sensor heads.
Implementation Method 1
an optical sensor is used for the film thickness measurement
Data Source
AI summary
A polishing apparatus that polishes a substrate includes a polishing table for holding a polishing pad and a polishing head configured to press a surface of the substrate against the polishing pad. A plurality of first optical heads detect a signal concerning a film thickness of the substrate while moving across the substrate. One spectrometer receives and processes signals output by at least two first sensor heads among the plurality of first sensor heads. An optical switch selectively connects the sensor heads to the spectrometer. A processor controls the optical switch to switch, at timing when the plurality of sensor heads simultaneously face the substrate, the connection to the spectrometer from one sensor head to another sensor head.