Grooved CMP Pads for Uniform Polishing
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Solution Overview
Problem
Current CMP polishing pads face issues with non-uniform polishing due to edge effects and center slow effects, as well as ineffective slurry transport and distribution, leading to reduced flatness and overall polishing efficiency.
Innovation Solution
The development of novel groove configurations for CMP pads, including primary and secondary grooves, and optional terminal grooves, which are designed to prevent hydroplaning, ensure slurry distribution, control localized stiffness, and facilitate debris removal, using methods such as molding, laser writing, and 3-D printing to create in-situ grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP pads without grooves are used, then the pad structure is simple and easy to manufacture, but slurry transport and distribution are ineffective leading to non-uniform polishing
Solution Approach 1:
The polishing pad surface is segmented into multiple groove features including radial grooves, circumferential grooves, and cross-hatch grooves. These grooves divide the slurry flow path into multiple channels, ensuring uniform slurry distribution across the pad surface and preventing hydroplaning, thereby improving polishing uniformity while maintaining a manageable structural complexity
Solution Approach 2:
Different groove patterns are applied to different regions of the pad surface. Radial grooves are used in certain sectors while circumferential grooves are used in other sectors, with cross-hatch patterns providing additional slurry distribution. This localized variation in groove configuration optimizes slurry transport in different regions, achieving uniform polishing across the entire pad surface
2Manufacturing precision
If ex-situ groove designs are used, then slurry distribution is improved, but the grooves cannot be directly tailored to specific polishing requirements and are less effective
Solution Approach 1:
The groove configuration is designed to dynamically adapt to polishing conditions. The combination of radial, circumferential, and cross-hatch grooves creates a flexible slurry distribution system that can respond to varying polishing pressures, speeds, and slurry flow rates, enhancing both slurry distribution precision and adaptability to different polishing requirements
Solution Approach 2:
The groove system performs multiple functions simultaneously: radial grooves provide primary slurry distribution, circumferential grooves prevent hydroplaning and control slurry flow direction, and cross-hatch grooves enhance slurry penetration. This multi-functional groove design achieves precise slurry distribution while being adaptable to various polishing conditions and requirements
3Productivity
If macro-texturing with ex-situ grooves is used, then slurry transport is enhanced, but the grooves do not provide in-situ control and are less effective at preventing hydroplaning
Solution Approach 1:
The groove system is segmented into multiple functional components: radial grooves for slurry distribution, circumferential grooves for hydroplaning prevention, and cross-hatch grooves for enhanced slurry penetration. This segmentation allows each groove type to specialize in its function, improving both slurry transport efficiency and hydroplaning prevention reliability
Solution Approach 2:
The circumferential grooves act as intermediary channels that collect slurry from radial grooves and redistribute it across the pad surface. These grooves mediate between the slurry source and the polishing surface, ensuring continuous slurry supply and preventing hydroplaning by maintaining direct contact between slurry and pad surface
4Ease of manufacture
If perforations are used for slurry distribution, then the pad structure is simple, but the method is ineffective as there is no direct channeling to the wafer surface
Solution Approach 1:
Instead of simple perforations, the pad surface is segmented into a network of grooves including radial, circumferential, and cross-hatch patterns. These grooves provide structured channels that actively transport slurry to the wafer surface, significantly improving slurry distribution effectiveness while maintaining ease of manufacture through conventional molding techniques
Solution Approach 2:
The groove system functions as a hydraulic network for slurry transport. The grooves are designed to channel slurry flow efficiently from the pad periphery to the center and across the surface, using fluid dynamics principles to ensure direct slurry delivery to the wafer surface, thereby improving distribution effectiveness
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 novel groove configurations enhance polishing uniformity, improve slurry distribution, and reduce defectivity by controlling the polishing process, leading to higher efficiency and better surface finish.
Implementation Method 1
designed to prevent hydroplaning
Implementation Method 2
slurry transport and distribution
Implementation Method 3
control localized stiffness
Implementation Method 4
facilitate debris removal
Data Source
AI summary
CMP pads having novel groove configurations are described. For example, described herein are CMP pads comprising primary grooves, secondary grooves, a groove pattern center, and an optional terminal groove. The CMP pads may be made from polyurethane or poly (urethane-urea), and the grooves produced therein may be made by a method from the group consisting of molding, laser writing, water jet cutting, 3-D printing, thermoforming, vacuum forming, micro-contact printing, hot stamping, and mixtures thereof.