Polishing Pad Micro-Grooves for Uniform Planarization
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Solution Overview
Problem
Conventional polishing pads fail to achieve uniform local planarization on semiconductor wafers due to large differences between groove sizes and microchip features, leading to non-uniform slurry distribution and instability in the conditioning process, which affects the consistency and uniformity of planarization.
Innovation Solution
A polishing pad with a plurality of soluble fibers forming micro-grooves up to 150 micrometers in width and depth, which self-regenerate during polishing by dissolving in an aqueous slurry, providing a high surface density of micro-grooves optimized for specific CMP applications, and combining with an insoluble component for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional grooves are provided on the polishing pad surface, then slurry distribution is improved, but local planarization uniformity deteriorates due to large size differences between grooves and microchip features
Solution Approach 1:
The invention segments the groove structure into two scales: conventional macro-grooves for overall slurry distribution and micro-grooves (5-50 micrometers wide) for local planarization. This multi-scale segmentation allows each groove type to address specific requirements, with micro-grooves matching the dimensions of microchip features to achieve uniform local planarization while macro-grooves maintain overall slurry distribution.
Solution Approach 2:
The invention adds a micro-scale dimension to the existing macro-groove structure by incorporating micro-grooves of 5-50 micrometers width. This dimensional addition creates a hierarchical groove system where micro-grooves handle local planarization at the feature level, while macro-grooves maintain bulk slurry distribution, thereby resolving the contradiction between overall slurry distribution and local planarization uniformity.
2Manufacturing precision
If asperities are provided on the pad surface to improve local planarization, then feature-scale planarization is improved, but process stability deteriorates due to continuous deformation and uncontrolled severance during conditioning
Solution Approach 1:
The micro-grooves are pre-formed during pad manufacturing at controlled dimensions (5-50 micrometers width, 0.1-5 micrometers depth), eliminating the need for subsequent conditioning processes to create these features. This preliminary action ensures consistent micro-groove geometry throughout the pad's service life, preventing the instability and uncontrolled changes associated with conditioning-induced asperity formation.
Solution Approach 2:
The micro-grooves are designed to self-regenerate during normal polishing operation through controlled dissolution of the soluble fiber material that forms the grooves. This self-service mechanism maintains consistent groove dimensions without requiring external conditioning intervention, thereby ensuring process stability while maintaining feature-scale planarization uniformity.
3Quantity of substance
If macro-grooves are used for slurry distribution, then overall slurry distribution is improved, but feature-level slurry distribution deteriorates due to large groove dimensions compared to microchip features
Solution Approach 1:
The invention segments the slurry distribution function across two groove scales: macro-grooves (0.010-0.050 inches wide) for overall slurry distribution and micro-grooves (5-50 micrometers wide) for feature-level slurry distribution. This segmentation allows each groove type to optimize for its specific function, with micro-grooves matching the 0.35 micrometer feature sizes to ensure uniform feature-level slurry distribution while macro-grooves maintain overall distribution efficiency.
Solution Approach 2:
The invention introduces a micro-scale dimension (5-50 micrometers) to complement the existing macro-groove structure, creating a hierarchical groove system. This dimensional addition enables the pad to simultaneously address both overall slurry distribution at the macro level and feature-level slurry distribution at the micro level, resolving the contradiction between the two requirements.
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 self-regenerating micro-grooves ensure uniform and efficient planarization, reducing slurry consumption, extending pad life, and minimizing conditioning needs, while maintaining consistent surface properties, thereby improving the polishing process and reducing costs.
Implementation Method 1
a plurality of soluble fibers having a diameter in the range of about 5 to 80 micrometers, and an insoluble component. The pad may also include a first surface having a plurality of micro-grooves, wherein the soluble fibers form the micro-grooves in the pad
Data Source
AI summary
A polishing pad is provided herein, which may include a plurality of soluble fibers having a diameter in the range of about 5 to 80 micrometers, and an insoluble component. The pad may also pad include a first surface having a plurality of micro-grooves, wherein the soluble fibers form the micro-grooves in the pad. The micro-grooves may have a width and/or depth up to about 150 micrometers. In addition, a method of forming the polishing pad and a method of polishing a surface with the polishing pad is disclosed.