Grinding apparatus, method of grinding workpiece, and method of manufacturing substrate

Abstract

There is disclosed a grinding apparatus for grinding one surface side of a workpiece in which modified layers are present on the one surface side, including a holding unit for holding the workpiece such that the one surface side is exposed, a grinding unit for grinding the one surface side of the workpiece held by the holding unit, a capturing unit for capturing the one surface side of the workpiece held by the holding unit, and a controller that determines whether grinding of the one surface side of the workpiece is to be terminated, with reference to information regarding the modified layers obtained by capturing of the one surface side of the workpiece that is performed in a state in which grinding of the one surface side of the workpiece is performed in parallel or is suspended.

What is claimed is: 
     
         1 . A grinding apparatus for grinding one surface side of a workpiece in which modified layers are present on the one surface side, comprising:
 a holding unit for holding the workpiece such that the one surface side is exposed;   a grinding unit for grinding the one surface side of the workpiece held by the holding unit;   a capturing unit for capturing the one surface side of the workpiece held by the holding unit; and   a controller that determines whether grinding of the one surface side of the workpiece is to be terminated, with reference to information regarding the modified layers obtained by capturing of the one surface side of the workpiece that is performed in a state in which grinding of the one surface side of the workpiece is performed in parallel or is suspended.   
     
     
         2 . The grinding apparatus according to  claim 1 , further comprising:
 a processing chamber cover that surrounds a processing chamber capable of accommodating the workpiece held by the holding unit, the grinding unit, and the capturing unit,   wherein the processing chamber cover includes a partition wall for partitioning the processing chamber into a grinding space in which grinding of the one surface side of the workpiece is performed and a capturing space in which capturing of the one surface side of the workpiece is performed.   
     
     
         3 . The grinding apparatus according to  claim 1 , further comprising:
 a grinding liquid supplying unit for supplying a grinding liquid to a region to be ground of the one surface side of the workpiece; and   a fluid jetting unit for jetting fluid to the one surface side of the workpiece, in order to prevent the grinding liquid from entering a region to be captured of the one surface side of the workpiece.   
     
     
         4 . The grinding apparatus according to  claim 2 , further comprising:
 a grinding liquid supplying unit for supplying a grinding liquid to a region to be ground of the one surface side of the workpiece; and   a fluid jetting unit for jetting fluid to the one surface side of the workpiece, in order to prevent the grinding liquid from entering a region to be captured of the one surface side of the workpiece.   
     
     
         5 . The grinding apparatus according to  claim 1 ,
 wherein the holding unit has a chuck table for holding the workpiece on a holding surface, a motor for rotating the chuck table with a straight line passing through a center of the holding surface as a rotational axis, and an encoder that detects a rotational angle of the chuck table, and   the controller identifies that an element linearly extending along a direction which changes according to the rotational angle in the workpiece captured by the capturing unit is the modified layer.   
     
     
         6 . The grinding apparatus according to  claim 2 ,
 wherein the holding unit has a chuck table for holding the workpiece on a holding surface, a motor for rotating the chuck table with a straight line passing through a center of the holding surface as a rotational axis, and an encoder that detects a rotational angle of the chuck table, and   the controller identifies that an element linearly extending along a direction which changes according to the rotational angle in the workpiece captured by the capturing unit is the modified layer.   
     
     
         7 . The grinding apparatus according to  claim 3 ,
 wherein the holding unit has a chuck table for holding the workpiece on a holding surface, a motor for rotating the chuck table with a straight line passing through a center of the holding surface as a rotational axis, and an encoder that detects a rotational angle of the chuck table, and   the controller identifies that an element linearly extending along a direction which changes according to the rotational angle in the workpiece captured by the capturing unit is the modified layer.   
     
     
         8 . The grinding apparatus according to  claim 4 ,
 wherein the holding unit has a chuck table for holding the workpiece on a holding surface, a motor for rotating the chuck table with a straight line passing through a center of the holding surface as a rotational axis, and an encoder that detects a rotational angle of the chuck table, and   the controller identifies that an element linearly extending along a direction which changes according to the rotational angle in the workpiece captured by the capturing unit is the modified layer.   
     
     
         9 . The grinding apparatus according to  claim 1 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         10 . The grinding apparatus according to  claim 2 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         11 . The grinding apparatus according to  claim 3 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         12 . The grinding apparatus according to  claim 4 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         13 . The grinding apparatus according to  claim 5 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         14 . The grinding apparatus according to  claim 6 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         15 . The grinding apparatus according to  claim 7 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         16 . The grinding apparatus according to  claim 8 ,
 wherein the controller changes a grinding condition with reference to the information when grinding of the one surface side of the workpiece is performed.   
     
     
         17 . A method of grinding a workpiece which grinds one surface side of the workpiece in which modified layers are present on the one surface side, comprising:
 a holding step of holding the workpiece such that the one surface side thereof is exposed; and   a grinding step of grinding the one surface side of the workpiece after the holding step is performed,   wherein a determination as to whether the grinding step is to be terminated is made with reference to information regarding the modified layers obtained by capturing of the one surface side of the workpiece that is performed in a state in which grinding of the one surface side of the workpiece is performed in parallel or is suspended.   
     
     
         18 . A method of manufacturing a substrate having a thickness less than a predetermined thickness from an ingot having the predetermined thickness, the method comprising:
 a modified layer forming step of moving, relative to each other, the ingot and a focused spot on which a laser beam with a wavelength transmittable through a material of the ingot is focused, in a state in which the focused spot is positioned in the ingot, thereby forming modified layers in the ingot;   a substrate manufacturing step of, after the modified layer forming step is performed, with the modified layers as an initiating point, separating the ingot, thereby manufacturing the substrate having on one surface side thereof the modified layers remaining thereon; and   a grinding step of, after the substrate manufacturing step is performed, grinding the one surface side of the substrate,   wherein a determination as to whether the grinding step is to be terminated is made with reference to information regarding the modified layers obtained by capturing of the one surface side of the substrate that is performed in a state in which grinding of the one surface side of the substrate is performed in parallel or is suspended.