Polishing Device Retaining Ring Shape Measurement
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Solution Overview
Problem
The existing polishing devices face challenges in maintaining a consistent polishing profile due to variations in the 3D shape of the retaining ring, which affects the edge portion of the substrate, and this inconsistency is difficult to control, especially when the retaining rings change over time or are manufactured with varying precision.
Innovation Solution
A polishing device equipped with a sensor to measure the surface shape of the retaining ring and a controller to determine the polishing conditions based on the measured shape, allowing for real-time adjustments to maintain a consistent polishing profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pressing force of the retaining ring is set to a predetermined value, then the polishing process is simplified, but the polishing profile of the substrate edge portion becomes inconsistent due to 3D shape variations of the retaining ring bottom face
Solution Approach 1:
The system performs preliminary measurement of the retaining ring's 3D shape using a sensor before polishing. Based on the measured shape data, the controller pre-calculates and sets the appropriate pressing force for that specific retaining ring configuration, enabling consistent polishing profiles without requiring manual adjustment or break-in procedures
Solution Approach 2:
The system implements a feedback mechanism where the sensor continuously monitors the retaining ring's 3D shape, and the controller adjusts the pressing force in real-time based on the measured shape variations. This closed-loop control ensures that despite manufacturing variations or wear, the polishing profile remains consistent
2Manufacturing precision
If conventional break-in procedures are performed to complete the 3D shape of the retaining ring, then polishing profile consistency improves, but apparatus operation rate decreases and additional costs are incurred
Solution Approach 1:
Instead of relying on time-consuming break-in procedures, the system uses a sensor to measure the actual 3D shape of the retaining ring bottom face and provides real-time feedback to the controller. The controller then adjusts the pressing force accordingly, achieving consistent polishing profiles immediately without requiring dummy substrate polishing or break-in periods
Solution Approach 2:
The system replaces the mechanical break-in process (which involves physically wearing in the retaining ring through dummy substrate polishing) with a measurement and control system. The sensor measures the retaining ring shape, and the controller compensates for variations through adjusted pressing force, eliminating the need for mechanical break-in procedures
3Manufacturing precision
If the 3D shape of the retaining ring bottom face is strictly controlled during manufacturing, then polishing profile reproducibility improves, but manufacturing cost increases
Solution Approach 1:
Instead of strictly controlling the physical 3D shape parameters of the retaining ring during manufacturing, the system changes the control parameter to pressing force. The sensor measures the actual shape, and the controller adjusts the pressing force to compensate for shape variations, achieving consistent polishing profiles without requiring high-precision manufacturing
Solution Approach 2:
The system implements feedback control where the sensor measures the retaining ring's 3D shape and the controller adjusts the pressing force accordingly. This allows standard manufacturing processes to be used while still achieving high polishing profile reproducibility through active compensation
Data Source
AI summary
A polishing device is provided to suppress deterioration in reproducibility of a polishing profile due to a variation or change with time of a shape of a retaining ring of a substrate holding member for each of retaining rings. The polishing device includes: a polishing head configured to press a substrate against a polishing pad and have a retainer ring surrounding the substrate pressed against the polishing pad; a measurement sensor configured to measure a surface shape of the retainer ring; and a controller configured to determine a polishing condition of the substrate based on the surface shape of the retainer ring measured by the measurement sensor.