Method of recycling a delaminated wafer and a silicon wafer used for the recycling

Abstract

There is disclosed a method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing. There are provided a method of appropriately reprocessing a delaminated wafer produced as a by-product in a hydrogen ion delaminating method to reuse it as a silicon wafer actually, and particularly, a method of reprocessing an expensive wafer such as an epitaxial wafer many times for reuse, to improve productivity of SOI wafer having a high quality SOI layer, and to reduce producing cost.

What is claimed is:  
     
         1 . A method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing.  
     
     
         2 . A method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method in which an epitaxial wafer is used as a bond wafer by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing.  
     
     
         3 . A method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method in which CZ wafer is used as a bond wafer by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing.  
     
     
         4 . A method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method in which FZ wafer is used as a bond wafer by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing.  
     
     
         5 . The method of recycling a delaminated wafer according to    claim 1   , wherein a surface oxide film is removed before polishing for removal of a step in the peripheral part, as the reprocessing.  
     
     
         6 . The method of recycling a delaminated wafer according to    claim 2   , wherein a surface oxide film is removed before polishing for removal of a step in the peripheral part, as the reprocessing.  
     
     
         7 . The method of recycling a delaminated wafer according to    claim 3   , wherein a surface oxide film is removed before polishing for removal of a step in the peripheral part, as the reprocessing.  
     
     
         8 . The method of recycling a delaminated wafer according to    claim 4   , wherein a surface oxide film is removed before polishing for removal of a step in the peripheral part, as the reprocessing.  
     
     
         9 . The method of recycling a delaminated wafer according to    claim 1   , wherein a stock removal in the polishing for removal of the step in the peripheral part as the reprocessing is 1 to 2 microns.  
     
     
         10 . The method of recycling a delaminated wafer according to    claim 2   , wherein a stock removal in the polishing for removal of the step in the peripheral part as the reprocessing is 1 to 2 microns.  
     
     
         11 . The method of recycling a delaminated wafer according to    claim 3   , wherein a stock removal in the polishing for removal of the step in the peripheral part as the reprocessing is 1 to 2 microns.  
     
     
         12 . The method of recycling a delaminated wafer according to    claim 4   , wherein a stock removal in the polishing for removal of the step in the peripheral part as the reprocessing is 1 to 2 microns.  
     
     
         13 . The method of recycling a delaminated wafer according to    claim 1   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon, for 6 hours or less.  
     
     
         14 . The method of recycling a delaminated wafer according to    claim 2   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon, for 6 hours or less.  
     
     
         15 . The method of recycling a delaminated wafer according to    claim 3   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon, for 6 hours or less.  
     
     
         16 . The method of recycling a delaminated wafer according to    claim 4   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon, for 6 hours or less.  
     
     
         17 . The method of recycling a delaminated wafer according to    claim 1   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon for 1 to 300 seconds through use of a rapid heating/rapid cooling apparatus.  
     
     
         18 . The method of recycling a delaminated wafer according to    claim 2   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon for 1 to 300 seconds through use of a rapid heating/rapid cooling apparatus.  
     
     
         19 . The method of recycling a delaminated wafer according to    claim 3   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon for 1 to 300 seconds through use of a rapid heating/rapid cooling apparatus.  
     
     
         20 . The method of recycling a delaminated wafer according to    claim 4   , wherein the heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed at a temperature in the range from 1000° C. to a melting point of silicon for 1 to 300 seconds through use of a rapid heating/rapid cooling apparatus.  
     
     
         21 . The method of recycling a delaminated wafer according to    claim 1   , wherein said heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed in 100% hydrogen atmosphere or a mixed atmosphere of hydrogen and argon.  
     
     
         22 . The method of recycling a delaminated wafer according to    claim 2   , wherein said heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed in 100% hydrogen atmosphere or a mixed atmosphere of hydrogen and argon.  
     
     
         23 . The method of recycling a delaminated wafer according to    claim 3   , wherein said heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed in 100% hydrogen atmosphere or a mixed atmosphere of hydrogen and argon.  
     
     
         24 . The method of recycling a delaminated wafer according to    claim 4   , wherein said heat treatment in a reducing atmosphere containing hydrogen as the reprocessing is performed in 100% hydrogen atmosphere or a mixed atmosphere of hydrogen and argon.  
     
     
         25 . The method of recycling a delaminated wafer, wherein the delaminated wafer reprocessed by the method according to    claim 1    is reused as a bond wafer of an SOI wafer.  
     
     
         26 . The method of recycling a delaminated wafer, wherein the delaminated wafer reprocessed by the method according to    claim 2    is reused as a bond wafer of an SOI wafer.  
     
     
         27 . The method of recycling a delaminated wafer, wherein the delaminated wafer reprocessed by the method according to    claim 3    is reused as a bond wafer of an SOI wafer.  
     
     
         28 . The method of recycling a delaminated wafer, wherein the delaminated wafer reprocessed by the method according to    claim 4    is reused as a bond wafer of an SOI wafer.  
     
     
         29 . A silicon wafer for reuse, wherein the silicon wafer is obtained by being reprocessed according to the method of    claim 1   .  
     
     
         30 . A silicon wafer for reuse, wherein the silicon wafer is obtained by being reprocessed according to the method of    claim 2   .  
     
     
         31 . A silicon wafer for reuse, wherein the silicon wafer is obtained by being reprocessed according to the method of    claim 3   .  
     
     
         32 . A silicon wafer for reuse, wherein the silicon wafer is obtained by being reprocessed according to the method of    claim 4   .