Lobed CMP Polishing Pad Structures for Fluid Path Reduction
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Solution Overview
Problem
Conventional chemical mechanical polishing pads face challenges in achieving effective contact with the surface being polished due to the long distance polishing fluid travels over protruding structures, leading to reduced removal rates and potential wear issues.
Innovation Solution
The polishing pad features protruding structures with a cross-section defined by parametric equations, having three or more lobes and a Delta parameter between 0.2 and 0.75, which reduces the distance fluid travels and enhances mechanical integrity, ensuring better contact and structural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional protruding structures are used on polishing pads, then the pad can maintain structural integrity, but the fluid travel distance becomes too long which reduces removal rates
Solution Approach 1:
The protruding structures utilize curved surfaces and rounded geometries rather than sharp edges or flat surfaces. This curvature reduces the effective fluid travel path while maintaining structural integrity, allowing shorter fluid distances that improve removal rates without compromising pad strength
Solution Approach 2:
The invention optimizes specific geometric parameters of the protruding structures including height, base diameter, and curvature radius. By carefully controlling these parameters, the design achieves the optimal balance between maintaining structural integrity and minimizing fluid travel distance to maximize removal rate
2Force
If protruding structures are made taller to improve contact, then contact pressure increases, but structural integrity and wear resistance decrease
Solution Approach 1:
The curved, rounded geometry of the protruding structures distributes mechanical stresses more evenly throughout the structure. This curvature prevents stress concentration at sharp edges or tips, allowing the structures to maintain higher contact pressures without compromising structural integrity or increasing wear
Solution Approach 2:
The protruding structures are pre-formed with optimized geometries during pad manufacturing that anticipate and prepare for the mechanical stresses they will encounter during polishing. This preliminary structural optimization ensures they can withstand contact pressures while maintaining integrity throughout their service life
3Ease of manufacture
If the polishing pad uses simpler structures, then manufacturing is easier, but polishing uniformity and defect reduction are compromised
Solution Approach 1:
The polishing pad surface is segmented into multiple discrete protruding structures rather than using a continuous complex pattern. This segmentation allows each individual structure to be manufactured with consistent geometry using standard molding techniques, achieving polishing uniformity through repetitive modular units rather than complex monolithic designs
Data Source
AI summary
A polishing pad useful in chemical mechanical polishing comprises a base, and a plurality of structures protruding from the base wherein a portion of the plurality of structures are defined by a cross section having a perimeter which defines an area. The perimeter can be defined by parametric equations and can have six or more inflection points or the cross-section can comprise three or more lobes. The cross-section has a Delta parameter in the range of 0.2 to 0.75.