Patent ID: 8888877
Filing Date: 2014-11-18
Classification: B24B,B24D,C09G

Abstract:
1. A method of preparing a alkaline-earth metal oxide-containing polishing pad useful for polishing at least one of semiconductor, magnetic and optical substrates comprising: a. introducing a feed stream of gas-filled polymeric microelements into a gas jet, the polymeric microelements having varied density, varied wall thickness and varied particle size, the polymeric microelements having alkaline-earth metal oxide-containing regions distributed on an outer surface of the polymeric microelements, the alkaline-earth metal oxide-containing regions being spaced to coat 1 to 40 percent of the outer surface of the polymeric microelements; and being associated with greater than a 0.1 weight percent total of the following: i) alkaline-earth metal oxide-containing particles having a particle size of greater than 5 μm; ii) alkaline-earth metal oxide-containing regions covering greater than 50 percent of the outer surface of the polymeric microelements; and polymeric microelements agglomerated with alkaline-earth metal oxide-containing-particles to an average cluster size of greater than 120 μm; b. passing the polymeric microelements in the gas jet adjacent a Coanda block, the Coanda block having a curved wall for separating the polymeric microelements with Coanda effect, inertia and gas flow resistance; c. separating the i) alkaline-earth metal oxide-containing particles having a particle size of greater than 5 μm; ii) alkaline-earth metal oxide-containing regions covering greater than 50 percent of the outer surface of the polymeric microelements; and iii) polymeric microelements agglomerated with alkaline-earth metal oxide-containing particles to an average cluster size of greater than 120 μm associated with the polymeric microelements from the curved wall of the Coanda block to clean the polymeric microelements; d. collecting the polymeric microelements with less than 0.1 weight percent total of the polymeric microelements being associated with i) alkaline-earth metal oxide-containing particles having a particle size of greater than 5 μm; ii) alkaline-earth metal oxide-containing regions covering greater than 50 percent of the outer surface of the polymeric microelements; and iii) polymeric microelements agglomerated with alkaline-earth metal oxide-containing particles to an average cluster size of greater than 120 μm; and e. inserting the polymeric microelements into a polymeric matrix to form a polishing pad.