Polishing pad, polishing apparatus and method for polishing wafer

Abstract

A polishing apparatus includes a belt-type surface plate stretched between two rollers each having a rotation shaft arranged in parallel to that of the other roller, a plurality of sheet-type polishing pads stuck on the surface plate, and a dresser for activating the polishing pads. Part of an upper end portion of each of the polishing pads facing an adjacent one of the polishing pads has an obtuse angle. Thus, the dresser is not caught by the upper end portion of each of the polishing pads, so that the generation of a scratch in the polishing pads. Therefore, a semiconductor wafer can be polished without causing a scratch thereon.

What is claimed is:  
     
         1 . A polishing pad which is set under a wafer unit in chemical mechanical polishing and includes an upper surface serving as a polishing surface, 
 wherein at least part of an upper end portion of the polishing pad has a tapered shape or a curved section.    
     
     
         2 . The polishing pad of  claim 1 , 
 wherein the polishing pad has an approximately quadrangular shape when being viewed from the top and at least an upper end of part of the approximately quadrangular shape corresponding to a side is tapered or curved.    
     
     
         3 . The polishing pad of  claim 1 , 
 wherein the polishing pad has a fan shape when being viewed from the top and said at least part of the upper end portion of the polishing pad has a tapered shape or a curved section.    
     
     
         4 . The polishing pad of  claim 1 , 
 wherein said at least part of an upper end portion is tapered and an angle of the upper end portion is an obtuse angle.    
     
     
         5 . The polishing pad of  claim 1 , 
 wherein a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.    
     
     
         6 . A polishing pad which is set under a wafer unit in chemical mechanical polishing and includes an upper surface serving as a polishing surface, 
 wherein a first convex-and-concave portion is formed in at least part of an end portion of the polishing pad and    a second convex-and-concave portion which can be exactly fitted to the first convex-and-concave portion is formed in at least part of another end portion of the polishing pad.    
     
     
         7 . The polishing pad of  claim 6 , 
 wherein when being viewed from the top, the polishing pad has an approximately quadrangular shape, the first convex-and-concave portion is formed on a first side and the second convex-and-concave portion is formed on an opposite side to the first side.    
     
     
         8 . The polishing pad of  claim 6 , 
 wherein a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.    
     
     
         9 . A polishing pad which is set under a wafer unit in chemical mechanical polishing and includes an upper surface serving as a polishing surface, 
 wherein a corner portion of the polishing pad, when being viewed from the top, has a tapered shape or a curved section.    
     
     
         10 . The polishing pad of  claim 9 , 
 wherein when being viewed from the top, the polishing pad has a shape obtained by cutting off four corners or an approximately quadrangular shape with curved corners obtained by rounding four corners.    
     
     
         11 . The polishing pad of  claim 9 , 
 wherein a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.    
     
     
         12 . A polishing pad which is set under a wafer unit in chemical mechanical polishing and includes an upper surface serving as a polishing surface, 
 wherein in at least part of an end portion of the polishing pad, a first protruding portion formed by making an upper part of the end portion protrude is provided and    in at least part of another end portion of the polishing pad, a second protruding portion which is formed by making a lower part of the end portion and can be overlapped with the first protruding portion is provided.    
     
     
         13 . The polishing pad of  claim 12 , 
 wherein the polishing pad has an approximately quadrangular shape when being viewed from the top, the first protruding portion is formed on a first side and the second protruding portion is formed on an opposite side to the first side.    
     
     
         14 . The polishing pad of  claim 12 , 
 wherein a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.    
     
     
         15 . A polishing pad which is set under a wafer unit in chemical mechanical polishing and includes an upper surface serving as a polishing surface, 
 wherein a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.    
     
     
         16 . A polishing apparatus which includes a surface plate, a plurality of polishing pads stuck on the surface plate so as to be spaced apart from one another and each having an upper surface serving as a polishing surface, a carrier for holding a wafer in polishing and a dresser for activating an upper surface of each of the plurality of polishing pads, and is for use in chemical mechanical polishing of the wafer, 
 wherein an upper end portion of each said polishing pad has part facing an adjacent one of the polishing pads and having a tapered shape or a curved section.    
     
     
         17 . The polishing apparatus of  claim 16 , further comprising at least two rollers each having a rotation shaft arranged in parallel to that of the other roller, 
 wherein the surface plate is a belt-type and stretched between the two rollers, and    wherein each said polishing pad has an approximately quadrangular shape in which at least an upper end portion located on a side of the quadrangular shape is tapered or curved.    
     
     
         18 . A polishing apparatus which includes a surface plate, a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, a carrier for holding a wafer in polishing and a dresser for activating an upper surface of each of the plurality of polishing pads, and is for use in chemical mechanical polishing of the wafer, 
 wherein a first convex-and-concave portion is formed in at least part of an end portion of each said polishing pad and    a second convex-and-concave portion which is exactly fitted to the first convex-and-concave portion of an adjacent one of the plurality of polishing pads is formed in at least part of another end portion each said polishing pad.    
     
     
         19 . The polishing apparatus of  claim 18 , 
 wherein each said polishing pad has an approximately quadrangular shape in which the first convex-and-concave portion is formed on a first side and the second convex-and-concave portion is formed on an opposite side to the first side, when being viewed from the top.    
     
     
         20 . A polishing apparatus which includes a surface plate, a plurality of polishing pads stuck on the surface plate so as to be spaced apart from one another and each having an upper surface serving as a polishing surface, a carrier for holding a wafer in polishing and a dresser for activating an upper surface of each of the plurality of polishing pads, and is for use in chemical mechanical polishing of the wafer, 
 wherein each said polishing pad has a corner portion having a tapered shape or a curved section when being viewed from the top.    
     
     
         21 . A polishing apparatus which includes a surface plate, a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, a carrier for holding a wafer in polishing and a dresser for activating an upper surface of each of the plurality of polishing pads, and is for use in chemical mechanical polishing of the wafer, 
 wherein in each said polishing pad, a first protruding portion is formed in an end portion located in the upstream side with respect to an operation direction in polishing and    in each said polishing pad, a second protruding portion obtained by making lower part of the end portion protrude and be overlapped to the first protruding portion of an adjacent one of the polishing pads is formed in an end portion located in the downstream side with respect to the operation direction in polishing.    
     
     
         22 . The polishing apparatus of  claim 21 , 
 wherein each said polishing pad has an approximately quadrangular shape when being viewed from the top, the first protruding portion is formed on a first side and the second protruding portion is formed on an opposite side to the first side.    
     
     
         23 . A polishing apparatus which includes a surface plate, a plurality of polishing pads stuck on the surface plate so as to be spaced apart from one another and each having an upper surface serving as a polishing surface, a carrier for holding a wafer in polishing and a dresser for activating an upper surface of each of the plurality of polishing pads, and is for use in chemical mechanical polishing of the wafer, 
 wherein a space between adjacent ones of the plurality of polishing pads is filled with an adhesive agent.    
     
     
         24 . A polishing apparatus which includes a surface plate, a plurality of polishing pads stuck on the surface plate so as to be spaced apart from one another and each having an upper surface serving as a polishing surface, a carrier for holding a wafer in polishing and a dresser for activating an upper surface of each of the plurality of polishing pads, and is for use in chemical mechanical polishing of the wafer, 
 wherein in each said polishing pad, a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.    
     
     
         25 . A method for polishing a wafer using a polishing apparatus which includes a surface plate and a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, the method comprising the steps of: 
 a) activating the upper surface of each said polishing pad by a dresser; and    b) polishing the wafer by pressing the wafer against the upper surface of each said polishing pad while scanning the surface plate,    wherein each of the plurality of polishing pads used in the steps a) and b) has part of an upper end portion facing to adjacent one of the polishing pads and having a tapered shape or a curved section.    
     
     
         26 . A method for polishing a wafer using a polishing apparatus which includes a surface plate and a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, the method comprising the steps of: 
 a) activating the upper surface of each said polishing pad by a dresser; and    b) polishing the wafer by pressing the wafer against the upper surface of each said polishing pad while scanning the surface plate,    wherein a first convex-and-concave portion is formed in an end portion of each said polishing pad used in the steps a) and b) and a second convex-and-concave portion which is exactly fitted to the first convex-and-concave portion of an adjacent one of the polishing pads is formed in another end portion of each said polishing pad.    
     
     
         27 . A method for polishing a wafer using a polishing apparatus which includes a surface plate and a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, the method comprising the steps of: 
 a) activating the upper surface of each said polishing pad by a dresser; and    b) polishing the wafer by pressing the wafer against the upper surface of each said polishing pad while scanning the surface plate,    wherein each of the plurality of polishing pads used in the steps a) and b) has a corner portion having a tapered shape or curved section when being viewed from the top.    
     
     
         28 . A method for polishing a wafer using a polishing apparatus which includes a surface plate and a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, the method comprising the steps of: 
 a) activating the upper surface of each said polishing pad by a dresser; and    b) polishing the wafer by pressing the wafer against the upper surface of each said polishing pad while scanning the surface plate,    wherein in an end portion of each said polishing pad used in the steps a) and b) located in the upstream side with respect to the scanning direction of the surface plate, a first protruding portion obtained by making an upper portion of the end portion protrude is formed, and in another end portion of each said polishing pad located in the downstream side with respect to the scanning direction of the surface plate, a second protruding portion obtained by making a lower portion of said another end is formed.    
     
     
         29 . A method for polishing a wafer using a polishing apparatus which includes a surface plate and a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, the method comprising the steps of: 
 a) activating the upper surface of each said polishing pad by a dresser; and    b) polishing the wafer by pressing the wafer against the upper surface of each said polishing pad while scanning the surface plate,    wherein a space between adjacent ones of the plurality of polishing pads used in the steps a) and b) is filled with an adhesive agent.    
     
     
         30 . A method for polishing a wafer using a polishing apparatus which includes a surface plate and a plurality of polishing pads stuck on the surface plate and each having an upper surface serving as a polishing surface, the method comprising the steps of: 
 a) activating the upper surface of each said polishing pad by a dresser; and    b) polishing the wafer by pressing the wafer against the upper surface of each said polishing pad while scanning the surface plate,    wherein in each of the plurality of polishing pads used in the steps a) and b), a through hole of which a peripheral portion has an upper end having a tapered shape or a curved section is further provided.