CMP Pad Tapered Trenches Slurry Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chemical mechanical polishing pads face challenges in retaining sufficient slurry and effectively removing debris to prevent wafer surface scratching during the polishing process.
Innovation Solution
A chemical mechanical polishing pad design featuring a base portion and a polishing portion with tapered trenches that accommodate more slurry and include tunnels for uniform distribution, along with a support layer that can adjust density for enhanced planarization and removal rates, manufactured using additive manufacturing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the polishing pad uses conventional trench structures, then the structure is simple, but the slurry retention is insufficient and debris removal is ineffective
Solution Approach 1:
The polishing pad is divided into multiple functional zones: a base portion and a polishing portion with tapered trenches. The trenches are segmented into different regions (opening region, intermediate region, bottom region) with varying widths to optimize both slurry retention and debris removal. This segmentation allows each region to perform its specific function while maintaining overall structural simplicity.
Solution Approach 2:
Different regions of the trench have different local properties: the opening region has a larger width for debris removal, the intermediate region transitions smoothly, and the bottom region has a smaller width for slurry retention. This local quality variation optimizes both slurry retention and debris removal without requiring complex overall structure.
2Productivity
If the polishing pad uses uniform density structure, then the manufacturing is simple, but the planarization and removal rates cannot be optimized
Solution Approach 1:
The polishing pad employs a density gradient structure where the base portion has a first density and the polishing portion has a second density different from the first. This local quality variation in density allows the polishing portion to achieve higher removal rates while the base portion provides structural stability, optimizing overall productivity without complex manufacturing.
Solution Approach 2:
The patent changes the physical parameter of density across different portions of the polishing pad. By adjusting the density parameter from the base portion to the polishing portion, the pad achieves optimized planarization and removal rates. This parameter change is implemented through additive manufacturing techniques that can vary material properties during the manufacturing process.
3Quantity of substance
If the trench opening width is larger than the remaining portion, then debris removal is easier, but slurry retention is reduced
Solution Approach 1:
The trench is segmented into three regions with different width characteristics: the opening region with larger width for debris removal, the intermediate region for transition, and the bottom region with smaller width for slurry retention. This segmentation resolves the contradiction by assigning different functions to different segments.
Solution Approach 2:
The trench features a tapered shape with curved transitions between regions rather than sharp angles. The smooth curvature from the opening region through the intermediate region to the bottom region optimizes fluid dynamics for both slurry retention and debris removal, eliminating the need for extreme width differences.
Data Source
AI summary
A chemical mechanical polishing pad includes a base portion and a polishing portion. The base portion has opposite first and second side surfaces. The polishing portion extends from the first side surface away from the second side surface, has a polishing surface facing away from the base portion, and has at least one trench formed in the polishing surface. Each of the trenches has an opening defined by the polishing surface. A horizontal width of the opening of each of the trenches is equal to or smaller than that of the remaining portion of the trench. The chemical mechanical polishing pad is made by laminating a plurality of polymer layers.