CMP Retainer Ring Conical Transition Wear Reduction
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Solution Overview
Problem
The existing chemical mechanical polishing (CMP) process faces challenges in extending the service life of retainer rings and polishing pads due to wear caused by friction and pressure, leading to reduced effectiveness and increased downtime and costs.
Innovation Solution
A retainer ring with a conical transition region, specifically a 45-degree taper, is designed to reduce wear by gradually applying pressure and extending the service life, and channels with varying tapers are incorporated to minimize wear overhead during the CMP process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional retainer ring with a sharp outer edge is used, then the ring can effectively hold the substrate during polishing, but the sharp edge causes increased wear to both the ring and the polishing pad
Solution Approach 1:
The patent applies curvature by replacing the sharp outer edge with a conical transition region that gradually curves from the outer surface to the front surface. This curved geometry distributes contact pressure more evenly across the polishing pad, preventing the concentrated wear that occurs at sharp edges while maintaining effective substrate retention.
Solution Approach 2:
The patent changes the geometric parameters of the retainer ring by introducing a conical transition region with a specific taper angle (45 degrees). This parameter modification transforms the edge geometry from sharp to gradual, reducing the mechanical stress concentration and thereby decreasing wear on both the ring and polishing pad during the polishing process.
2Duration of action of stationary object
If the transition region is extended to maximize wear reduction, then service life is improved, but the ring structure becomes more complex
Solution Approach 1:
The conical transition region provides a smooth curved transition that extends the service life by reducing wear. The geometric simplicity of a conical shape allows this extended transition region to be implemented without significantly increasing manufacturing complexity, as it can be produced using standard machining operations.
3Productivity
If channels are added to the retainer ring to improve slurry flow, then polishing effectiveness is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the retainer ring by incorporating channels that divide the internal structure into separate flow paths. This segmentation improves slurry distribution and polishing effectiveness by ensuring uniform slurry flow across the polishing interface, while the channels can be integrated into the ring manufacturing process using standard techniques.
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 conical transition region and channel tapers effectively reduce wear on the retainer ring and polishing pad, extending their service life and minimizing production overhead, thereby improving the CMP process efficiency and reducing costs.
Implementation Method 1
wear caused by friction and pressure
Data Source
AI summary
A retainer ring is provided for use in conjunction with Chemical Mechanical Polishing apparatus which polishing is used to polish a substrate. Particularly, the retainer ring includes an inner surface defining a retainer area, an outer surface, a front surface extending between the inner and outer surface, the front surface being in contact with the polishing pad during polishing and a transition region between the outer surface and the front surface. A CMP apparatus which includes at least a ring having the above features is also provided for.