CMP Retaining Ring Extension for Edge Damage Reduction
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes often result in non-uniformities and damage near the edges of substrates due to unpredictable forces from the interaction with the retaining ring during semiconductor manufacturing.
Innovation Solution
The introduction of an extension member with a controlled hardness, extending radially outward from the substrate chuck member, which contacts the retaining ring instead of the substrate, and adjustable support plate stops that can alter the force application to improve polishing uniformity and reduce damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate directly contacts the retaining ring during CMP processing, then the substrate can be retained in the carrier, but the substrate edge and retaining ring are damaged due to unpredictable impact forces
Solution Approach 1:
The patent introduces an extension member as an intermediary element between the substrate and the retaining ring. This extension member contacts the retaining ring instead of the substrate directly, mediating the interaction forces and preventing direct impact damage to the substrate edge while maintaining substrate retention stability.
2Reliability
If the substrate shifts and impacts the retaining ring, then the substrate can be retained in the carrier, but non-uniformities are created near the substrate edge during polishing
Solution Approach 1:
The extension member serves as a mediator that controls the interaction between the substrate system and the retaining ring. By providing a dedicated contact interface, it prevents substrate-induced non-uniformities while maintaining reliable substrate positioning throughout the polishing process.
3Reliability
If the retaining ring contacts the substrate with unpredictable forces, then the substrate can be held in the carrier, but damage occurs to both the substrate and retaining ring
Solution Approach 1:
The extension member acts as a protective intermediary that distributes and controls the contact forces between the substrate system and the retaining ring. This mediation prevents concentrated impact forces that would otherwise damage both the substrate and retaining ring, while maintaining stable substrate holding.
4Reliability
If the substrate edge interacts with the retaining ring, then the substrate can be retained, but the force direction is unpredictable causing polishing non-uniformities
Solution Approach 1:
The extension member provides a controlled interface that mediates the force transmission between the substrate system and the retaining ring. This intermediary structure enables predictable force direction and magnitude, eliminating the unpredictable forces that cause polishing non-uniformities near the substrate edge.
Data Source
AI summary
An apparatus for chemical mechanical polishing (CMP) of a substrate is described herein. The apparatus includes an extension disposed between a retaining ring and a chucking membrane. The extension is disposed radially outward from the edge of the substrate and is configured to contact the retaining ring during substrate processing. The extension provides a repeatable and controlled point of contact between the retaining ring and the chucking membrane. The extension may have multiple configurations, such that the contact point between the retaining ring and the chucking membrane is set at a pre-determined location or such that the contact point is moveable by an adjustable stop.