Process for producing glass substrate

Abstract

The present invention relates to a process for producing a glass substrate, the process including: a lapping step of grinding a main surface of a glass substrate; and a main-surface polishing step of polishing the main surface of the glass substrate after the lapping step, in which the lapping step includes: a primary lapping step of grinding the main surface of the glass substrate with a free abrasive or a fixed abrasive; a secondary lapping step of grinding the main surface of the glass substrate with a fixed abrasive having a smaller particle size than the free abrasive or the fixed abrasive used in the primary lapping step; and a cleaning step of cleaning the main surface of the glass substrate by at least one selected from the group consisting of ultrasonic cleaning, scrub cleaning and acid cleaning, after the primary lapping step but before the secondary lapping step.

1 . A process for producing a glass substrate, said process comprising:
 a lapping step of grinding a main surface of a glass substrate; and   a main-surface polishing step of polishing the main surface of the glass substrate after the lapping step,   wherein the lapping step comprises:   a primary lapping step of grinding the main surface of the glass substrate with a free abrasive or a fixed abrasive;   a secondary lapping step of grinding the main surface of the glass substrate with a fixed abrasive having a smaller particle size than the free abrasive or the fixed abrasive used in the primary lapping step; and   a cleaning step of cleaning the main surface of the glass substrate by at least one selected from the group consisting of ultrasonic cleaning, scrub cleaning and acid cleaning, after the primary lapping step but before the secondary lapping step.   
     
     
         2 . The process for producing a glass substrate according to  claim 1 , further comprising, after the lapping step but before the main-surface polishing step, a cleaning step of cleaning the main surface of the glass substrate by at least one selected from the group consisting of ultrasonic cleaning, scrub cleaning and acid cleaning. 
     
     
         3 . The process for producing a glass substrate according to  claim 1 , wherein the acid cleaning includes cleaning the main surface of the glass substrate with a fluorine-based solution. 
     
     
         4 . The process for producing a glass substrate according to  claim 1 , wherein the cleaning step includes cleaning the main surface of the glass substrate by the acid cleaning, followed by cleaning with a detergent containing an alkali. 
     
     
         5 . The process for producing a glass substrate according to  claim 1 , wherein the glass substrate is a glass substrate for a magnetic disk.