Three-Region Polishing Pad Groove Pattern for CMP Uniformity
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Solution Overview
Problem
Conventional CMP polishing pad designs fail to optimize slurry utilization and polishing performance, leading to reduced removal rates and increased costs due to inefficiencies in slurry distribution and polishing uniformity.
Innovation Solution
A three-region polishing pad with a high-rate path groove structure, defined by specific geometric equations, that aligns with carrier grooves to enhance slurry flow and distribution, improving polishing uniformity and removal rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing pad groove patterns are used, then the polishing pad structure is simple and easy to manufacture, but slurry utilization is poor and removal rate is reduced
Solution Approach 1:
The polishing pad surface is segmented into multiple groove patterns including radial grooves, concentric circular grooves, Cartesian grid grooves, and spiral grooves. Each groove type serves specific functions in different regions of the polishing pad to optimize slurry distribution and removal rate
Solution Approach 2:
Different groove patterns are applied to different regions of the polishing pad based on local requirements. For example, radial grooves may be used in the center region while concentric circular grooves are used in the outer region, allowing each area to have optimal slurry flow characteristics for its specific polishing conditions
2Manufacturing precision
If uniform groove width and depth are used, then the groove configuration is simple to manufacture, but polishing uniformity across the wafer is poor
Solution Approach 1:
The groove width and depth are varied in different regions of the polishing pad. For instance, grooves in the outer region may have different dimensions compared to grooves in the inner region, allowing optimization of polishing uniformity across the entire wafer surface while accounting for varying slurry flow and pressure conditions in different areas
Solution Approach 2:
The groove configuration transitions from uniform to non-uniform dimensions, creating a dynamic pattern that adapts to the varying conditions across the polishing pad surface. This dynamic variation in groove parameters helps maintain consistent polishing performance across the wafer
3Productivity
If slurry flow is increased to improve removal rate, then polishing productivity increases, but slurry cost and waste increase
Solution Approach 1:
The groove system segments the slurry flow path into multiple channels, directing slurry efficiently to areas where it is most needed. This segmentation allows better utilization of the same amount of slurry, improving removal rate without proportionally increasing slurry consumption
Solution Approach 2:
The groove patterns act as intermediaries that facilitate slurry distribution. The grooves guide and distribute slurry throughout the polishing pad, ensuring efficient slurry utilization and reducing waste while maintaining high removal rates
Data Source
AI summary
The invention provides a polishing pad useful for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium with a polishing pad. The polishing pad comprises a center, an inner region surrounding the center, a transition region connecting grooves from the inner region to an outer region surrounding the inner region. The outer region has multiple grooves with a high-rate path. The transition region is adjacent the outer region and within a radius from the center defined as follows:rTR=0.7r*to1.3r*wherer*=RC(RRC)2-cos(2θc0)-sin(2θc0)(R/RCcosθc0)2-1;with the inner region originating continuous grooves that extend uninterrupted to the outer region.