Multi-Layer Polishing Pad With Composite Abrasive Slurry
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Solution Overview
Problem
Conventional abrasive processes for polishing ultrahard substrates, such as sapphire, face challenges including inadequate material removal rates, poor surface finish, subsurface damage, and high costs, making them difficult and costly to implement effectively.
Innovation Solution
A polishing system featuring a multi-layered polishing pad with cavities and a polishing solution containing abrasive composite particles, which includes a ceramic matrix with diamond or cubic boron nitride particles, is used to mechanically and chemically remove material from the substrate, providing improved removal rates and surface finish while reducing costs through efficient abrasive particle utilization and easy pad replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional abrasive processes are used for polishing ultrahard substrates, then material removal can be achieved, but the removal rate is inadequate and the process is costly
Solution Approach 1:
The patent changes the physical and chemical parameters of the abrasive system by using composite abrasive particles with specific hardness, size distribution, and composition ratios. The slurry contains abrasive particles with controlled concentration and size ranges (e.g., 0.5-5 micrometers) to optimize both removal rate and efficiency, directly addressing the inadequate removal rate while reducing process costs through parameter optimization
Solution Approach 2:
The patent employs composite abrasive particles consisting of multiple materials combined in specific ratios, such as diamond or cubic boron nitride particles embedded in a ceramic matrix or bonded to a substrate. These composite structures provide enhanced cutting ability and durability, improving material removal rate while extending abrasive life and reducing overall process cost
2Manufacturing precision
If conventional abrasive processes are used, then polishing can be performed, but surface finish quality is poor
Solution Approach 1:
The patent applies local quality by using abrasive particles with specific size distributions and compositions tailored for different polishing stages. The slurry contains a mixture of particle sizes where finer particles (0.5-2 micrometers) provide superior surface finish in final polishing stages, while coarser particles handle material removal, achieving high surface finish quality without requiring complex multi-step processes
Solution Approach 2:
The patent optimizes surface finish quality by controlling abrasive particle parameters including size (0.5-5 micrometers), concentration (5-50 wt%), and hardness. By adjusting these parameters, the process achieves high manufacturing precision with a relatively simple polishing setup, reducing the need for complex process equipment
3Reliability
If conventional abrasive processes are used, then polishing can be performed, but subsurface damage occurs
Solution Approach 1:
The patent reduces subsurface damage by optimizing abrasive particle parameters including using particles with controlled size (0.5-5 micrometers), appropriate hardness ratios, and specific concentration ranges (5-50 wt%). These parameter controls ensure gentle yet effective material removal that minimizes subsurface damage while maintaining process simplicity through a single slurry-based polishing step
Solution Approach 2:
The patent uses composite abrasive particles with carefully selected material compositions and structural configurations. The composite structure allows for controlled cutting action that removes material efficiently while minimizing subsurface damage, maintaining ease of manufacture through a straightforward slurry application process
4Productivity
If large abrasive particles are used to achieve high removal rates, then material removal rate improves, but surface finish deteriorates
Solution Approach 1:
The patent applies local quality by incorporating a distribution of abrasive particle sizes within the slurry, with finer particles (0.5-2 micrometers) concentrated in regions where surface finish is critical. This size distribution allows larger particles to handle bulk material removal while smaller particles refine the surface, achieving both high removal rate and excellent surface finish simultaneously
Solution Approach 2:
The patent creates composite abrasive systems combining particles of different sizes and materials in specific ratios. The composite slurry contains a mixture where coarser particles provide cutting action for high removal rates while finer particles embedded in the matrix or present in the slurry deliver superior surface finish, resolving the trade-off between productivity and manufacturing precision
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 system achieves high material removal rates and surface finishes comparable to large abrasive particles while maintaining persistent performance without extensive pad dressing, reducing costs and subsurface damage, and allowing for efficient abrasive particle utilization and easy pad replacement.
Implementation Method 1
The abrasive layer includes agglomerate abrasive grains which are particles selected from a group including diamond particles, silicon carbide particles, zirconium oxide particles, modified ceramic aluminum oxide particles, and cubic boron nitride particles
Data Source
Figure 1~3
Figure 4~6A
Figure 6B~7
AI summary
A multi-layered polishing pad arrangement includes a first polishing pad layer having a first top and a first bottom major surface, a second polishing pad layer having a second top and a second bottom major surface, and a coupling arrangement disposed between the first bottom surface and the second top surface. The thickness of each of the first and second polishing pad layer ranges between 0.125 mm and 10 mm.