CMP Carrier Membrane Failure Detection via Optical Fluid Sensing
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Solution Overview
Problem
Membrane failures in chemical mechanical polishing systems lead to pressure integrity loss, substrate damage, and fluid ingress, causing uneven polishing, substrate loss, and system downtime.
Innovation Solution
Implementing sensors to monitor the pressure system for fluid ingress and membrane integrity, using optical sensors to detect fluid presence through lensing and total internal reflection effects, and a control system to alert and adjust operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane integrity monitoring is implemented using sensors, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical monitoring systems with optical sensing. The optical sensor detects membrane failures by measuring changes in light transmission or reflection properties when fluid ingress occurs, substituting mechanical pressure sensors or visual inspection systems with a non-contact optical detection method that simplifies the overall system architecture while maintaining high reliability
Solution Approach 2:
The patent introduces an optical intermediary (light) as the detection medium between the membrane and the monitoring system. The optical sensor uses light transmission or reflection through/around the membrane area to detect fluid ingress indirectly, avoiding direct contact with the membrane or polishing fluid while providing reliable failure detection
2Measurement precision
If optical sensors are used to detect fluid ingress, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent exploits changes in optical parameters (light transmission, reflection, or absorption characteristics) that occur when polishing fluid ingress is detected. By monitoring these optical parameter changes rather than using complex mechanical or electrical sensors, the system achieves high measurement precision for fluid detection while keeping the sensor system relatively simple and robust
3Reliability
If continuous monitoring is implemented, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent implements periodic or intermittent optical monitoring rather than truly continuous monitoring. The optical sensor can be activated at key moments (e.g., during polishing cycles, at transitions between operations, or at scheduled intervals) to detect fluid ingress, providing sufficient reliability for process monitoring while significantly reducing energy consumption compared to constant monitoring
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
Prevents substrate damage, ensures uniform polishing, and minimizes system downtime by detecting membrane failures and fluid ingress, maintaining system integrity.
Implementation Method 1
optical sensors to detect fluid presence through lensing and total internal reflection effects
Implementation Method 2
optical sensors to detect fluid presence through lensing and total internal reflection effects
Data Source
AI summary
A polishing system includes a pressure system, a substrate carrier including a membrane, a first sensor, and a control system. A first compartment of the membrane is fluidly coupled to the pressure system. The first sensor is configured to monitor the pressure system and produce a first output based on conditions detected in the pressure system. The control system coupled to the first sensor and configured to process the first output to produce a first processed output, and the control system configured to compare the first processed output to a threshold to detect a presence of a fluid in the pressure system.