Eddy Current Sensor for Real-Time Substrate Damage Detection
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Solution Overview
Problem
Conventional polishing apparatuses for semiconductor wafers face issues such as damage during polishing, leading to increased maintenance time and reduced throughput due to the inability to immediately detect substrate damage or slipping out of the top ring, and the need for separate inspections for remaining metal films, which prolong processing time.
Innovation Solution
The implementation of an eddy current sensor integrated into the polishing table that scans the substrate surface during polishing to monitor changes in output and detect damage or slipping, allowing for real-time detection and adjustment of polishing conditions, thereby reducing maintenance time and improving processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polishing apparatuses are used without real-time detection, then the polishing process can be performed, but substrate damage cannot be immediately detected leading to increased maintenance time and reduced throughput
Solution Approach 1:
The patent implements an eddy current sensor that continuously monitors the substrate surface during polishing and provides real-time feedback about substrate condition. When damage is detected through changes in eddy current sensor output, the system can immediately respond, preventing further damage and enabling timely maintenance, thus improving both reliability and productivity
Solution Approach 2:
The patent replaces conventional mechanical inspection methods with an eddy current sensor-based detection system. The eddy current sensor uses electromagnetic induction to detect substrate condition non-contactually during polishing, eliminating the need for separate mechanical inspection steps and enabling continuous real-time monitoring
2Measurement precision
If separate inspections for remaining metal films are performed after polishing, then film quality can be verified, but processing time is prolonged
Solution Approach 1:
The patent merges the polishing process with the inspection process by integrating the eddy current sensor into the polishing apparatus. The same sensor system that monitors substrate condition also detects remaining metal films, combining two separate operations into one simultaneous process, thereby eliminating additional inspection time while maintaining detection accuracy
Solution Approach 2:
The eddy current sensor operates continuously throughout the polishing process, constantly monitoring both substrate condition and remaining film thickness. This continuous monitoring eliminates the need for separate discontinuous inspection steps, maintaining productive action throughout the entire process and reducing total processing time
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
Enables immediate detection of substrate damage and slipping, shortens inspection and processing times, and allows for optimized polishing conditions by performing inspections during the process, thus enhancing the overall efficiency and capability of the CMP process.
Implementation Method 1
an eddy current sensor integrated into the polishing table that scans the substrate surface during polishing to monitor changes in output and detect damage
Data Source
AI summary
A polishing method polishes and planarizes a substrate. The substrate is pressed against a polishing surface on a rotating polishing table. During polishing, the polishing table is rotated, and the surface, being polished, of the substrate is scanned by an eddy current sensor provided in the polishing table. An output of the eddy current sensor is monitored, and substrate damage is detected from a change in the output of the eddy current sensor. Further, an output of an end point detecting sensor obtained by scanning the surface of the substrate is monitored, and the polishing end point is detected from a change in the output of the end point detecting sensor. After detecting the polishing end point, an output of the end point detecting sensor or another sensor is monitored, and detecting a film left on a part of the substrate is performed.