Method of grinding semiconductor wafers and device for grinding both surfaces of semiconductor wafers

Abstract

A method of grinding semiconductor wafers including simultaneously grinding both surfaces of multiple semiconductor wafers being ground by rotating the multiple semiconductor wafers between a pair of upper and lower rotating surface plates in a state where the multiple wafers are held on a carrier so that centers of the multiple wafers are positioned on a circumference of a single circle, wherein a ratio of an area of a circle passing through the centers of the multiple wafers to an area of one of the multiple wafers is greater than or equal to 1.33 but less than 2.0; a rotational speed of the multiple wafers falls within a range of 5 to 80 rpm; and the grinding of the multiple wafers with the rotating surface plates are conducted with fixed abrasive grains in the presence of an alkali solution.

1 . A method of grinding semiconductor wafers comprising:
 simultaneously grinding both surfaces of multiple semiconductor wafers being ground by rotating the multiple semiconductor wafers between a pair of upper and lower rotating surface plates in a state where the multiple semiconductor wafers are held on a carrier so that centers of the multiple semiconductor wafers are positioned on a circumference of a single circle, wherein   a ratio of an area of a circle passing through the centers of the multiple semiconductor wafers to an area of one of the multiple semiconductor wafers is greater than or equal to 1.33 but less than 2.0;   a rotational speed of the multiple semiconductor wafers falls within a range of 5 to 80 rpm; and   the grinding of the multiple semiconductor wafers with the rotating surface plates are conducted with fixed abrasive grains in the presence of an alkali solution.   
     
     
         2 . The method of grinding according to  claim 1 , wherein the alkali solution has a pH ranging from 12 to 15. 
     
     
         3 . The method of grinding according to  claim 1 , wherein the semiconductor wafers have a diameter ranging from 400 to 500 mm. 
     
     
         4 . The method of grinding according to  claim 1 , wherein the ratio of an area of a circle passing through the centers of the multiple semiconductor wafers to an area of one of the multiple semiconductor wafers is greater than or equal to 1.33 but less than or equal to 1.5. 
     
     
         5 . A device for grinding both surfaces of semiconductor wafers comprising:
 a pair of upper and lower rotating surface plates comprising fixed abrasive grains;   a sun gear provided in a rotating center portion between the upper and lower rotating surface plates;   a ring-shaped inner-toothed gear positioned on an outer circumference portion between the upper and lower rotating surface plates;   a carrier comprised of a planetary gear, the planetary gear meshing with the inner-toothed gear and sun gear and being positioned between the upper and lower rotating surface plates; and   an alkali solution feeder, wherein   the carrier has multiple holes configured to receive respective wafers being ground, and   centers of the multiple holes are positioned on a circumference of a single circle, with a ratio of an area of a circle passing through the centers of the multiple holes to an area of one of the wafers being ground greater than or equal to 1.33 but less than 2.0.   
     
     
         6 . The device for grinding according to  claim 5 , wherein the ratio of an area of a circle passing through the centers of the multiple holes to an area of one of the wafers being ground is greater than or equal to 1.33 but less than or equal to 1.5.