Substrate polishing system using roll-to-roll fixed abrasive

Abstract

A substrate polishing system includes two hollow drums and motors for driving the drums in a reciprocating manner. An abrasive tape wound on supply and takeup rollers is introduced, with the supply roller mounted inside one of the drums and the takeup roller mounted inside the other drum. The abrasive tape exits the interior of each drum through a slot in the surface of the drum. Between the drums the abrasive tape passes over a platen having a bearing surface. A substrate is mounted in a carrier and forced against the abrasive tape where it overlies the bearing surface. The drums are rotated reciprocally, thereby causing the abrasive tape to move back and forth over the platen and polishing the substrate. After a substrate has been polished the tape is advanced a selected distance by indexing motors that are connected to the supply and takeup rollers. After several substrates have been polished, each successive substrate is exposed to a section of the abrasive tape that has experienced the same amount of wear. Thus the uniformity of polishing between substrates is improved. Also, the use of the drums allows the tape to reach a desired speed in order to polish the substrate in a minimal period of time. Abrasive tape conditioners are positioned on the sides of the carrier. Because the tape moves back and forth under the conditioners, rather than only in a single direction, the cleaning of the tape is improved. In an alternative embodiment the tape is not abrasive and instead an abrasive slurry is applied to the tape.