Silicon Wafer Grinding Apparatus, Retaining Assembly Used for the Same and Silicon Wafer Flatness Correcting Method

Abstract

A silicon wafer grinding apparatus, a retaining assembly used for the same, and a silicon wafer flatness correcting method are provided. More particularly, a silicon wafer grinding apparatus, a retaining assembly used for the same, and a silicon wafer flatness correcting method for correcting a wafer flatness in a final grinding process are provided. The silicon wafer grinding apparatus includes a grinding surface plate having a grinding pad attached thereon; a grinding head arranged opposite to the grinding surface plate and rotated in the same direction as that of the grinding surface plate; a backing film attached at a lower portion of the grinding head for supporting a wafer; and a retainer ring having an inner diameter (a wafer diameter+α) greater than a diameter of the wafer by as much as α and disposed on the backing film. By forming a diameter or physical properties of a part of the backing film of the wafer retaining assembly, the wafer flatness of the final grinding may be corrected.

1 - 20 . (canceled) 
     
     
         21 . A wafer retaining assembly comprising: a circular retainer ring having an inner diameter greater than a wafer diameter, the retainer ring also having an outer diameter and a backing film including a pressure sensitive adhesive layer attached at a lower portion of the grinding head, a substrate layer formed on the pressure sensitive adhesive layer, a foaming layer formed on the substrate layer, which may be partly attached or detached, and an alignment mark marked at a center thereof. 
     
     
         22 . The wafer retaining assembly of  claim 21 , wherein the backing film further includes a cutting line for detaching at least one of the substrate layer and the foaming layer along a circumference direction. 
     
     
         23 . The wafer retaining assembly of  claim 22 , wherein the backing film further includes a cutting line for detaching all of the substrate layer and the foaming layer along a circumference direction. 
     
     
         24 . The wafer retaining assembly of  claim 22 , wherein the cutting line is formed at a predetermined interval of at least about 3 mm to about 5 mm from an inner wall of the retainer ring. 
     
     
         25 . The wafer retaining assembly of  claim 22 , wherein the cutting line is formed at an external periphery corresponding to about 40% of a radius of the backing film. 
     
     
         26 . The wafer retaining assembly of  claim 21 , wherein the backing film includes a groove portion along a circumference direction at a predetermined distance from the center thereof. 
     
     
         27 . The wafer retaining assembly of  claim 21 , wherein the groove portion has a width of from about 3 to about 5 mm from the inner wall of the retainer ring. 
     
     
         28 . The wafer retaining assembly of  claim 27 , wherein the groove portion has a width of less than about 2% to an inner diameter of the retainer ring. 
     
     
         29 . The wafer retaining assembly of  claim 21 , wherein at least one of the substrate layer, the foaming layer, and the pressure sensitive adhesive layer is formed with a different material than the other of the substrate layer, the foaming layer, and the pressure sensitive adhesive layer. 
     
     
         30 . The wafer retaining assembly of  claim 21 , wherein at least one of the substrate layer, the foaming layer, and the pressure sensitive adhesive layer has a different thickness than the other of the substrate layer, the foaming layer, and the pressure sensitive adhesive layer.