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Conditioning Abrasive Particles for Sapphire Fine Lapping With A Diamond Particle Fixed Abrasive Pad

IP.com Disclosure Number: IPCOM000239231D
Publication Date: 2014-Oct-22
Document File: 3 page(s) / 15K

Publishing Venue

The IP.com Prior Art Database

Abstract

A fixed abrasive lapping pad, having diamond agglomerate as the abrasive particle was used to lap C-plane sapphire wafers. A coolant was used that contained platelet calcined alumina, silicon carbide, or boron carbide particles as conditioning particles to condition or dress the fixed abrasive during the lapping process. Sapphire wafers lapped with coolants containing boron carbide conditioning particles have higher removal rates than wafers lapped with a coolant having silicon carbide or alumina conditioning particles. Sapphire wafers lapped with coolants containing silicon carbide conditioning particles have higher removal rates than wafers lapped with alumina conditioning particles.

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Page 01 of 3

Conditioning Abrasive Particles for Sapphire Fine Lapping With A Diamond Particle Fixed Abrasive Pad

Abstract:

     A fixed abrasive lapping pad, having diamond agglomerate as the abrasive particle was used to lap C-plane sapphire wafers. A coolant was used that contained platelet calcined alumina, silicon carbide, or boron carbide particles as conditioning particles to condition or dress the fixed abrasive during the lapping process. Sapphire wafers lapped with coolants containing boron carbide conditioning particles have higher removal rates than wafers lapped with a coolant having silicon carbide or alumina conditioning particles. Sapphire wafers lapped with coolants containing silicon carbide conditioning particles have higher removal rates than wafers lapped with alumina conditioning particles.

Background:

     The polishing or lapping of hard substrates, such as sapphire wafers, is typically accomplished by slurry or fixed abrasive processes. There is usually a tradeoff between the removal rate and the surface roughness of the substrate, as the removal rate increases (desirable) the surface roughness increases (undesirable). The industry is continually looking for new processes/technology to overcome this issue. WO 2007/015909A describes a fixed abrasives system using agglomerates of a first abrasives suitable for abrading or polishing the substrate and conditioning particles suitable for conditioning or dressing the agglomerate of the fixed abrasive and/or the polymeric matrix of the fixed abrasive. It was found that the use of alumina conditioning/dressing particles can drastically improve the removal rate with minimum sacrifice of surface roughness.

Experimental:

Fixed Abrasive Pad

      A fixed abrasive pad is prepared according to the procedure described in WO2007/015909, "Fixed Abrasive Article Preparation (Method I)". The abrasive particle is a 4 micron diamond abrasive particle.

Conditioning particles


Page 02 of 3

      Seven conditioning particles of varying particle sizes; platelet calcined alumina (PWA - 3 micron), green silicon carbide (SiC-GC - 2 micron and 4 micron), black si...