Polishing Pad Light Transmitting Region for CMP Monitoring
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Solution Overview
Problem
Current methods for monitoring the state of polishing pads in chemical mechanical polishing (CMP) processes lack accuracy in detecting changes in thickness and surface roughness, affecting the reliability of the CMP process.
Innovation Solution
Incorporating a light transmitting region in the polishing pad, which allows for real-time monitoring using a first optical displacement detection sensor, enabling accurate determination of when the pad needs conditioning or replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If eddy current sensor or optical distance measuring sensor is used to detect polishing pad thickness, then the monitoring function is provided, but the measurement precision is insufficient to accurately determine wear amount and thickness changes
Solution Approach 1:
The polishing pad incorporates a light transmitting region with specific optical properties (light transmitting polymer and light reflector) that differ from the surrounding polishing regions. This local quality enhancement enables the optical displacement detection sensor to accurately measure thickness changes and surface roughness by detecting light transmission characteristics through this specialized region, thereby resolving the measurement precision issue while maintaining process reliability
2Measurement precision
If conventional monitoring technology is used, then the polishing pad state can be checked, but the accuracy in determining when conditioning or replacement is needed is insufficient
Solution Approach 1:
The system continuously monitors the light transmission characteristics through the light transmitting region and provides real-time feedback on polishing pad condition. This feedback mechanism enables accurate determination of wear state and triggers timely conditioning or replacement decisions, optimizing productivity by avoiding both premature replacement and delayed maintenance
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 approach ensures the polishing pad is maintained in an optimal state, enhancing the reliability and efficiency of the CMP process by accurately monitoring changes in thickness and surface roughness, and determining the polishing termination point.
Implementation Method 1
a light transmitting region for monitoring a change in the state of the polishing pad
Implementation Method 2
detecting light reflected from the light transmitting region by the first optical displacement detection sensor
Data Source
AI summary
The embodiment relates to a polishing pad that comprises a top pad layer. The top pad layer comprises a light transmitting region for monitoring a change in the state of the polishing pad. The embodiment can efficiently monitor a change in the state of the polishing pad while the polishing process is carried out.