Recovery of abrasive particles used to process semiconductor articles

摘要

Process is used for the recovery of abrasive granules that have been used for the mechanical working of a semiconductor material. The granules and the grindings originating from the semiconductor are suspended in a fluid. In a first step, the composition is centrifuged. In a second step, the separated solids are redispersed in fresh fluid. Centrifuging is for 30-320, pref. 60-100, seconds, and at 2000-8000, pref. 4000-6000, g. The solids consist of 60-95 wt.% of abrasive particles and 2-8 wt.% of abraded semiconductor material. In an example, 25 kg of silicon carbide particles having an average diameter of 10 microns was dispersed in 20 kg of a cutting oil. Then 2000 discs of monocrystalline silicon having a diameter of 100 mm were subjected to lapping abrasion until the abrasive composition contained 1 kg of abraded material. It was then centrifuged for 70 seconds at 5000 g. The separated solids were redispersed in 16 kg. of fresh cutting oil. This new composition was capable of processing another 2000 silicon discs.