CMP Retainer Ring Slurry Passage Design
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Solution Overview
Problem
In chemical mechanical polishing (CMP) processes, slurry outside the retainer ring is typically blocked and not utilized, leading to insufficient slurry distribution between the semiconductor substrate and the polishing pad, which reduces polishing efficiency.
Innovation Solution
A retainer ring module with integrated slurry passages that allow slurry to be introduced from outside the retainer ring into the space between the substrate and the polishing pad, ensuring a sufficient amount of slurry is provided for improved polishing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the retainer ring blocks slurry outside the retainer ring, then the retainer ring maintains its traditional blocking function, but slurry is lost and polishing efficiency is reduced
Solution Approach 1:
The retainer ring is segmented with multiple slurry passages formed at different positions and angles, dividing the slurry flow path to allow slurry to enter the retainer ring from the outside while maintaining the blocking function in other areas. This segmentation enables selective slurry introduction without complete loss of the blocking function.
Solution Approach 2:
Different portions of the retainer ring have different functions: some areas block slurry while others have slurry passages that allow slurry entry. The slurry passages are positioned and angled to receive slurry from specific directions, creating local quality variations that optimize both blocking and slurry introduction functions simultaneously.
2Quantity of substance
If slurry passages are formed in the retainer ring, then slurry can be introduced into the space between substrate and polishing pad, but the retainer ring structure becomes more complex
Solution Approach 1:
The slurry passages are integrated directly into the retainer ring structure, merging the blocking function and slurry introduction function into a single component. This eliminates the need for separate slurry delivery mechanisms and reduces overall system complexity despite adding functional passages to the retainer ring.
Solution Approach 2:
The retainer ring serves multiple functions simultaneously: it blocks slurry from certain areas, introduces slurry through passages at specific angles, and maintains mechanical support for the polishing pad. This multi-functionality reduces the need for additional components and simplifies the overall system.
3Productivity
If slurry passages are positioned at downward slant angles, then slurry flows efficiently into the polishing space, but the outlet position becomes more constrained
Solution Approach 1:
The slurry passages are formed with curved or slanted paths rather than straight vertical channels, allowing slurry to flow efficiently at downward angles while accommodating the constrained height of the retainer ring. The curved geometry optimizes flow dynamics within the limited spatial envelope.
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 introduction of slurry through the retainer ring module reduces slurry loss and ensures a consistent supply to the polishing area, enhancing the overall efficiency of the CMP process.
Implementation Method 1
The slurry passage is formed in the retainer ring in a downward slant direction toward a central portion of the retainer ring to introduce the slurry to a space between the substrate and the polishing pad
Data Source
AI summary
An example retainer ring module includes a retainer ring and at least one slurry passage. The retainer ring is arranged on a lower surface of a polishing pad to surround a substrate on an upper surface of the polishing pad to which slurry may be provided. The at least one slurry passage is formed in the retainer ring in a downward slant direction toward a central portion of the retainer ring to introduce the slurry to a space between the substrate and the polishing pad.