CMP Pad Sensor Module for Acoustic Signal Detection
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Solution Overview
Problem
The existing chemical mechanical polishing (CMP) apparatuses face challenges in accurately detecting acoustic signals generated during the polishing process due to the attenuation of these signals as they pass through the encapsulation protective device (EPD) window.
Innovation Solution
The proposed solution involves a chemical mechanical polishing apparatus with a sensor module installed in the CMP pad's installation hole. This module includes a window at the upper end, a diaphragm below the window, a housing with an inclined internal surface, and a sensor positioned to detect acoustic waves generated during polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is provided to detect acoustic signals during CMP, then polishing degree monitoring is enabled, but the acoustic signal is weakened by the EPD window causing inaccurate detection
Solution Approach 1:
The sensor module is extracted from the conventional EPD window location and repositioned to utilize the installation hole in the CMP pad, eliminating the signal attenuation problem caused by the EPD window material while maintaining the protective function through the housing structure
Solution Approach 2:
The housing with inclined internal surface acts as an intermediary structure that guides and transmits acoustic signals from the wafer-CMP pad interface to the sensor, improving signal transmission efficiency and detection accuracy
2Measurement precision
If the sensor is positioned to directly detect acoustic signals from wafer-CMP pad contact, then detection sensitivity is improved, but the sensor is exposed to harsh polishing environment including slurry and mechanical stress
Solution Approach 1:
The housing serves as a protective intermediary that shields the sensor from direct exposure to slurry and mechanical stress while maintaining acoustic signal transmission capability through its inclined internal surface design
Solution Approach 2:
The housing structure acts as a protective shell that isolates the sensor from the harsh polishing environment, allowing the sensor to operate reliably without direct contact with slurry and mechanical stresses
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
The described configuration enhances the detection of acoustic signals, allowing for more accurate monitoring of the polishing process and improving the determination of the polishing degree of the wafer.
Implementation Method 1
a sensor in the installation hole to be below the filler, the sensor being configured to detect an acoustic wave generated during polishing of the wafer
Implementation Method 2
a housing below the window, the housing comprising an inclined internal surface
Data Source
AI summary
A chemical mechanical polishing apparatus includes: a platen; a chemical mechanical polishing (CMP) pad on an upper surface of the platen, the CMP pad comprising an installation hole; a polishing head on the platen, the polishing head being configured to bring a wafer W into contact with the CMP pad; a slurry supply unit configured to supply slurry to the CMP pad; and a sensor module in the installation hole of the CMP pad, wherein the sensor module includes: a window at an upper end of the installation hole; a housing below the window, the housing comprising an inclined internal surface; and a sensor below the housing.