Ceramic Abrasive Polishing Pad for Sapphire Substrates
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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 inefficient and difficult to implement effectively.
Innovation Solution
A system comprising a polishing pad with ceramic abrasive composites dispersed in a porous ceramic matrix, used in conjunction with a polishing solution, is employed to mechanically and chemically remove material from substrates, featuring a carrier assembly to move the pad relative to the substrate, enhancing material removal and surface finish.
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 material removal rate is inadequate and surface finish is poor
Solution Approach 1:
The polishing pad uses a composite structure combining a porous polymer base layer with an abrasive layer containing ceramic abrasive composites (such as diamond or cubic boron nitride particles embedded in a ceramic matrix). This composite material approach enables both high material removal rates and excellent surface finish by combining the mechanical strength of ceramics with the polishing effectiveness of ultrahard abrasive particles
Solution Approach 2:
The polishing pad incorporates a porous polymer base layer that allows polishing slurry to penetrate and distribute uniformly across the abrasive layer. The porous structure facilitates fluid flow, ensures consistent abrasive particle distribution, and maintains optimal contact between the polishing pad and substrate, thereby improving both productivity and surface finish
2Reliability
If conventional abrasive processes are used, then polishing can be performed, but subsurface damage occurs
Solution Approach 1:
The invention changes the physical and chemical parameters of the polishing system by using ultrahard ceramic abrasive particles (diamond, cubic boron nitride) with controlled particle sizes and hardness, combined with specifically formulated polishing slurries. These parameter changes enable effective material removal while minimizing subsurface damage through controlled mechanical and chemical mechanisms
Solution Approach 2:
The polishing slurry acts as an intermediary between the abrasive pad and the substrate. It facilitates the polishing process by providing lubrication, cooling, and chemical assistance, while the porous pad structure mediates the distribution of slurry and abrasive particles, ensuring uniform contact and reducing subsurface damage
3Ease of manufacture
If conventional polishing methods are used, then polishing operation can be maintained, but frequent pad dressing is required increasing operational costs
Solution Approach 1:
The polishing pad is designed with a porous polymer base layer that automatically absorbs and redistributes polishing slurry during operation. This self-service mechanism ensures continuous lubrication and cooling, prevents abrasive particle clogging, and maintains consistent polishing performance throughout the pad's service life, reducing the frequency of pad dressing operations
Solution Approach 2:
The porous structure of the polymer base layer enables automatic slurry absorption and distribution, allowing the pad to self-regulate during operation. This porous design prevents buildup of spent abrasive particles and maintains optimal polishing conditions, extending pad service life and reducing operational costs associated with frequent pad replacement or dressing
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 improved material removal rates and surface finishes comparable to large abrasive particles while minimizing subsurface damage and operational costs, maintaining effectiveness without frequent pad dressing.
Implementation Method 1
The polishing fluid includes a fluid component and a plurality of ceramic abrasive composites dispersed in the fluid component, the ceramic abrasive composites including individual abrasive particles dispersed in a porous ceramic matrix
Implementation Method 2
contacting the major surface of the substrate with the polishing pad and the polishing solution while there is relative motion between the polishing pad and the major surface of the substrate
Data Source
AI summary
A polishing system includes a first carrier assembly configured to receive and hold a substrate and a polishing pad. The polishing pad includes a top major surface and a bottom major surface positioned opposite the top major surface, and a plurality of polishing elements extending from the top major surface of the polishing pad. The system further includes a polishing solution disposed between the top surface of the polishing pad and the substrate. The polishing fluid includes a fluid component, and a plurality of ceramic abrasive composites dispersed in the fluid component, the ceramic abrasive composites including individual abrasive particles dispersed in a porous ceramic matrix. The system further includes a second carrier assembly configured to receive and hold the polishing pad. The system is configured such that the polishing pad is movable relative to the substrate to carry out a polishing operation.