SVM wafer lapping capabilities:
SVM provides wafer lapping services when there is a need to remove bulk amounts of material from a substrate. Bulk silicon removal is often a requirement in wafer reclaim and wafer thinning projects, as well as in major end uses like cell phones and modems.
What is wafer lapping?
Wafer lapping is a global planarization process that improves wafer flatness by removing surface damage, often from backside grinding. It is most common on silicon wafers, although certain applications require gallium arsenide (GaAs) and indium phosphide (InP) wafers to undergo this process as well. Lapping takes place between two counter-rotating cast iron plates and either an abrasive film or slurry. To adjust the penetration of the film/slurry, the wafers either spin faster or experience a heavier load to fit the target specification.
There are two ways to perform this process: free and fixed abrasive lapping.
Free abrasive lapping:
In free abrasive lapping, a slurry removes surface damage. The slurry consists of an abrasive powder floating in lapping oil. The abrasive powder is made with small particles (typically 5-20μm) of silicon carbide (SiC), aluminum oxide (Al2O3) or diamond, depending on the substrate material, diameter, and target thickness. Before depositing, the slurry spins in order to suspend the particles. When the slurry is ready, cast iron plates rotate slowly (< 80rpm) to distribute the film evenly across the wafer surface. After lapping, some wafers go through a second polishing to remove any remaining particles.
Fixed abrasive lapping:
Fixed abrasive lapping is the same process as free abrasive lapping. The only difference is that a thin SiC or other abrasive film deposits the particles on the substrate instead of using a slurry. The film consists of the same particles as free abrasive lapping on a thin polyester substrate. The film acts like sand-paper between the cast iron plates and the substrate, which rotates the same as free abrasive lapping. Ultimately, fixed abrasive lapping is much thicker than free abrasive lapping, which can produce superior flatness qualities and rounded edges.
Please CONTACT SVM for further information on our lapping services, to request a quote or to discuss your current requirements.