CMP Pad Groove Design for Dispersion Supply and Uniformity
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Solution Overview
Problem
Current chemical mechanical polishing pads face challenges in achieving high polishing rates and uniformity when the amount of aqueous dispersion is reduced, with existing designs failing to efficiently supply the dispersion and maintain contact area effectively.
Innovation Solution
The proposed polishing pad features specific groove designs, including first grooves that intersect a virtual straight line and second grooves that are either in contact or not in contact with each other, optimizing land ratios and distribution to enhance polishing efficiency and uniformity, even with reduced aqueous dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the density of grooves is increased to improve the supply of aqueous dispersion, then the polishing rate improves, but the contact area between the polishing surface and the surface to be polished decreases
Solution Approach 1:
The polishing pad employs different groove patterns in different regions: the first groove pattern (concentric circular grooves) is used in the central region where high dispersion supply is needed, while the second groove pattern (radial grooves) is used in the peripheral region where maintaining contact area is more important. This local differentiation allows each region to optimize its function without compromising the other.
Solution Approach 2:
The polishing pad surface is divided into multiple regions with different groove patterns. The pad includes a central region with the first groove pattern and peripheral regions with the second groove pattern, creating segmented functional zones that address different polishing requirements in different areas of the pad.
2Loss of substance
If the amount of aqueous dispersion is reduced to cut costs, then production costs decrease, but the polishing rate and uniformity deteriorate
Solution Approach 1:
The polishing pad utilizes a porous foam structure that can absorb and retain aqueous dispersion within its matrix. This porous structure allows the pad to supply dispersion to the polishing interface continuously even when the overall dispersion flow rate is reduced, maintaining high polishing rates while using less dispersion material.
Solution Approach 2:
The grooves are designed to pre-direct and channel the aqueous dispersion toward the polishing interface before the polishing action occurs. This preliminary channeling ensures that dispersion is delivered efficiently to where it is needed most, maximizing the effectiveness of each unit of dispersion and enabling reduced overall dispersion usage.
3Productivity
If the density of grooves is increased to improve the supply of aqueous dispersion, then the dispersion supply improves, but the in-plane uniformity of polishing decreases
Solution Approach 1:
Different groove patterns are applied to different regions of the polishing pad to optimize local performance. The concentric circular grooves in the center region enhance dispersion supply where the polishing pressure is highest, while the radial grooves in peripheral regions maintain adequate contact area and uniform dispersion distribution, achieving both efficient supply and good uniformity.
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 pad achieves high polishing rates and excellent in-plane uniformity, efficiently supplying the aqueous dispersion and maintaining contact area, even when the amount of aqueous dispersion is minimized.
Implementation Method 1
the polishing surface has at least two groups of grooves... serve to trap an aqueous dispersion for chemical mechanical polishing which is introduced into the center of the pad
Implementation Method 2
moved toward the periphery of the pad by centrifugal force
Implementation Method 3
chemical mechanical polishing is a technique for polishing by letting an aqueous dispersion for chemical mechanical polishing flow down over the surface of a chemical mechanical polishing pad while the polishing pad and the surface to be polished are brought into slide contact with each other
Data Source
AI summary
A chemical mechanical polishing pad of the present invention has the following two groups of grooves on the polishing surface: (i) a group of first grooves intersect a single virtual straight line extending from the center toward the periphery of the polishing surface and have a land ratio represented by the following equation of 6 to 30: Land ratio=(P−W)÷W (where P is the distance between adjacent intersections between the virtual straight line and the first grooves, and W is the width of the first grooves); and (ii) a group of second grooves extend from the center portion toward the peripheral portion of the polishing surface and consist of second grooves which are in contact with one another in the area of the center portion and second grooves which are not in contact with any other second grooves in the areas of the center portion. The chemical mechanical polishing pad of the present invention has a high polishing rate and excellent in-plane uniformity in the amount of polishing of the surface to be polished even when the amount of an aqueous dispersion for chemical mechanical polishing is made small.