Mechanical Polishing: Outlining Substrate Lapping

Lapping is a method of mechanical polishing that uses a soft-lap vehicle loaded with high-performance abrasive grains. It is often utilized after harsher grinding techniques and is used as a pre-polish to smooth subsurface damage in substrates while mitigating the risk of forming new surface defects. All forms of mechanical polishing that use an abrasive material run the risk of propagating new scratch defects due to the high-hardness and multi-faceted structures of the abrasive particles.

Saint-Gobain Surface Conditioning has developed specialty abrasive particles to limit this impact and reduce overall processing time and the need for additional correction steps. Particles can be customized for lapping processes that are designed to impart surface roughness prior to further polishing stages as well as for mechanical polishing of electronic substrates to achieve a defect-free and precisely uniform planar surface. In order to further reduce surface variability, it is vital that the abrasive is continuously suspended in the soft-lap vehicle. This can have the added benefit of allowing for abrasive recirculation and reuse.

Soft-lap vehicles generally fall under two categories: water-based; and oil-based lapping slurries.

Water-Based Lapping Slurries

Water-based lapping slurries are ideal for sustainable mechanical polishing processes, keeping lapping plates cool during operation while helping to minimize the accumulation of sludgy by-products due to their comparatively low-viscosity.
The MCA range of water-based lapping slurries from Saint-Gobain Surface Conditioning is comprised of alumina (Al2O3) abrasive in an aqueous solution. Additional corrosion inhibitors, dispersants, lubricants, and suspension additives are used to enhance the cut-rate of the abrasive to improve lapping throughput. This range is ideal for pre-polish lapping of ceramics, glass, and metals with extremely tight control of the substrate surface finish.

Oil-Based Lapping Slurries

Oil-based lapping slurries are generally better lubricating and offer higher efficiency mechanical polishing due to the adherent properties of the vehicle. This ensures the slurry remains in contact with the workpiece for longer to improve service life and optimize lapping performance.
Saint-Gobain’s MCA oil-based slurries include the 852D and 2242 alumina slurries, each of which is optimized for lapping a broad range of substrate materials from plastics and ceramics to hardened steel. These ready-to-use slurries can be diluted with either water or oil to alter the final viscosity of the product for distinct substrate lapping applications.

Mechanical Polishing with Saint-Gobain Surface Conditioning

Saint-Gobain Surface Conditioning is a world leader in the field of mechanical polishing. With unmatched experience in particle engineering and a holistic mentality when it comes to product formulation, we offer abrasive solutions that meet the modern challenges of electronic substrate lapping and polishing.

If you would like to learn more about our chemical mechanical polishing capabilities, read our previous blog post: CMP Polishing of Electronic Wafers. Otherwise, contact us directly if you have any questions.