CMP Retaining Ring Guiding Elements Slurry Capture
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Solution Overview
Problem
In chemical mechanical polishing (CMP) processes, a significant amount of slurry is wasted as the semiconductor wafer rotates or moves, with only 25% contributing to the polishing process, leading to inefficient use of the slurry.
Innovation Solution
A retaining ring with guiding elements around its outer surface is designed to capture and direct the slurry towards channels, improving the distribution and utilization of the slurry during the polishing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If slurry is continuously supplied to the polishing pad during CMP, then the polishing process can be maintained, but 75% of the slurry is wasted and only 25% contributes to the polishing process
Solution Approach 1:
The retaining ring is divided into multiple functional zones: a slurry capture area with guiding elements, a channel system, and a distribution area. This segmentation allows the slurry to be captured, directed through channels, and distributed to specific regions, ensuring that the slurry reaches the intended polishing areas rather than being wasted on the polishing pad surface
Solution Approach 2:
The retaining ring acts as an intermediary device between the slurry supply and the polishing interface. It captures the slurry, guides it through channels, and distributes it to the wafer or polishing pad, thereby controlling slurry flow and preventing waste while maintaining effective polishing
2Reliability
If a large amount of slurry is supplied to ensure adequate coverage, then polishing can proceed, but material usage efficiency decreases significantly
Solution Approach 1:
The guiding elements on the retaining ring automatically capture and guide the slurry flow without requiring external control mechanisms. The structure itself performs the function of directing slurry through its channels to the appropriate areas, ensuring reliable slurry distribution while minimizing waste through its self-regulating flow control
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 retaining ring effectively guides the slurry towards the wafer, enhancing the slurry's usage efficiency by ensuring that more of it contributes to the polishing process, reducing waste and improving material removal rates.
Implementation Method 1
The main body includes a plurality of channels configured to allow the slurry to flow into the inner space from the outer surface
Implementation Method 2
Each of the guiding elements forms a slurry capture area with the main body to guide the slurry towards each of the respective channels
Data Source
AI summary
The present disclosure provides a retaining ring for polishing a wafer by a slurry. The retaining ring includes a ring-shaped main body and a plurality of guiding elements. The main body has an outer surface, an inner surface, and an inner space for accommodating the wafer. The main body includes a plurality of channels configured to allow the slurry to flow into the inner space from the outer surface. The plurality of guiding elements is disposed at the outer surface of the main body with respect to the plurality of channels. Each of the guiding elements forms a slurry capture area with the main body to guide the slurry towards each of the respective channels.