Patent ID: 6709313
Filing Date: 2004-03-23
Classification: B24B

Abstract:
An apparatus for producing a polishing solution comprising pure water and abrasive grains, which apparatus comprises:a preparation tank (2) for preparing a polishing solution containing abrasive grains at a predetermined concentration, for mixing a abrasive grain-containing slurry as a feedstock and pure water; and a circulation device (L4) for circulating the thus prepared polishing solution to keep the solution in a suspended state, said circulation device (L4) comprising a circulation conduit (56) for circulating the polishing solution, and a flow-controllable bypass conduit (561) fluidly associated with the circulation conduit (56) and provided with a particle detector (7) for monitoring the polishing solution so as to detect large abrasive grains not smaller than a predetermined value and measure the number of the large abrasive grains, wherein said particle detector (7) is a light-extinction particle detector irradiating a predetermined quantity of light on a flow cell (74) fitted in a bypass conduit (561) so as to detect an attenuation of the light transmitted through the polishing solution flowing through the flow cell (74), the attenuation indicating the presence of the large abrasive grains, said flow cell (74) allowing the polishing solution to flow therethrough at a constant flow rate by flow control of the bypass conduit (561).