Wafer separation method, wafer separation and transfer method, and solar cell wafer separation and transfer method

Abstract

A wafer separation apparatus improves wafer separation performance in separation and transfer and suppresses the occurrence of wafer breakage in separation and transfer, while remaining inexpensive and small. The apparatus includes: a cassette that vertically accommodates a large number of single wafers in intimate contact with each other, the cassette being at least vertically opened; a cassette support that removably supports the cassette, the cassette support being at least vertically opened; a hoisting unit that hoists and lowers the cassette support integrally with the cassette; a liquid bath that accommodates a liquid into which the cassette support is immersed integrally with the cassette when the hoisting unit descends; a nozzle in the inside of the liquid bath to issue micro bubbles from the underside of the cassette support toward a large number of the wafers; and a micro bubble generator that generates micro bubbles to be issued from the nozzle.

1 . A wafer separation method comprising the steps of:
 an accommodating step of vertically accommodating a large number of single wafers in a cassette in intimate contact with each other, the cassette being at least vertically opened;   a mounting and supporting step of mounting and supporting the cassette on a cassette support at least vertically opened;   a lowering step of lowering the cassette support integrally with the cassette using a hoisting unit and immersing the wafers vertically arranged in a liquid in an inside of the liquid bath; and   a micro bubble issuing step of issuing micro bubbles generated in a micro bubble generator from an underside of the cassette support toward the wafers vertically arranged and causing the micro bubbles to enter and stay in a large number of the individual wafers.   
     
     
         2 . A wafer separation and transfer method comprising:
 an accommodating step of vertically accommodating a large number of single wafers in a cassette in intimate contact with each other, the cassette being at least vertically opened;   a mounting and supporting step of mounting and supporting the cassette on a cassette support at least vertically opened;   a lowering step of lowering the cassette support integrally with the cassette using a hoisting unit and immersing the wafers vertically arranged in a liquid in an inside of the liquid bath;   a micro bubble issuing step of issuing micro bubbles generated in a micro bubble generator from an underside of the cassette support toward the wafers vertically arranged and causing the micro bubbles to enter and stay in each space between a large number of the wafers;   a rotating step of rotating the cassette support integrally with the cassette to horizontally arrange a large number of the wafers using a rotating unit, while the micro bubbles enter and stay in each space between a large number of the wafers;   a hoisting step of hoisting the cassette support integrally with the cassette as the wafers are horizontally arranged using the hoisting unit and lifting a topmost wafer above at least a liquid level of the liquid bath;   an unloading step of unloading the topmost wafer lifted above the liquid level; and   a carrying step of carrying the unloaded wafer.   
     
     
         3 . A wafer separation and transfer method comprising:
 an accommodating step of vertically accommodating a large number of single wafers in a cassette in intimate contact with each other after removal of the wafers, the cassette being at least vertically opened;   a mounting and supporting step of mounting and supporting the cassette on a cassette support at least vertically opened;   a pre-washing step of lowering the cassette support integrally with the cassette using a hoisting unit and pre-washing the wafers vertically arranged;   an unloading and carrying step of unloading and carrying the cassette after pre-washed;   a lowering step of immersing the carried cassette in a liquid in an inside of a liquid bath;   a micro bubble issuing step of issuing micro bubbles generated in a micro bubble generator from an underside of the cassette support toward the wafers vertically arranged and causing the micro bubbles to enter and stay in each space between a large number of the wafers;   a rotating step of rotating the cassette support integrally with the cassette to horizontally arrange a large number of the wafers using a rotating unit, while the micro bubbles enter and stay in each space between a large number of the wafers;   a hoisting step of hoisting the cassette support integrally with the cassette as the wafers are horizontally arranged using the hoisting unit and lifting a topmost wafer above at least a liquid level of the liquid bath;   an unloading step of unloading the topmost wafer lifted above the liquid level; and   a carrying step of carrying the unloaded wafer.   
     
     
         4 . A solar cell wafer separation and transfer method comprising:
 a slicing step of slicing a silicon ingot integrally with a support plate into a large number of wafers;   a removing step of removing the sliced silicon ingot from the support plate for single wafers;   an accommodating step of vertically accommodating a large number of the single wafers in a cassette in intimate contact with each other after removal of the wafers, the cassette being at least vertically opened;   a mounting and supporting step of mounting and supporting the cassette on a cassette support at least vertically opened;   a lowering step of lowering the cassette support integrally with the cassette using a hoisting unit and immersing the wafers vertically arranged in a liquid in an inside of the liquid bath;   a micro bubble issuing step of issuing micro bubbles generated in a micro bubble generator from an underside of the cassette support toward the wafers vertically arranged and causing the micro bubbles to enter and stay in each space between a large number of the wafers;   a rotating step of rotating the cassette support integrally with the cassette to horizontally arrange a large number of the wafers using a rotating unit, while the micro bubbles enter and stay in each space between a large number of the wafers;   a hoisting step of hoisting the cassette support integrally with the cassette as the wafers are horizontally arranged using the hoisting unit and lifting a topmost wafer above at least a liquid level of the liquid bath;   an unloading step of unloading the topmost wafer lifted above the liquid level;   a carrying step of carrying the unloaded wafer; and   a transfer step of transferring the carried wafer to a solar cell fabrication apparatus.   
     
     
         5 . The wafer separation and transfer method according to  claim 2 , comprising:
 a collecting step of collecting automatically collecting the carried wafer in the carrying step in a wafer collection box; and   a subsequent step transfer step of automatically transferring the wafer collection box after collected to a subsequent step using a multi-robot arm.   
     
     
         6 . The solar cell wafer separation and transfer method according to  claim 4 ,
 wherein in the transfer step, the wafer is transferred to a chemical etching apparatus for texture treatment to fabricate a p-type wafer or n-type wafer.   
     
     
         7 . The wafer separation method according to  claim 1 ,
 wherein in the micro bubble issuing step, the nozzle or the cassette support is moved along a direction of arranging the wafers.   
     
     
         8 . The wafer separation method according to  claim 13 ,
 wherein before starting the micro bubble issuing step, five sides except the underside of the cassette support is covered with a cover as the cassette support is immersed in the inside of the liquid bath.   
     
     
         9 . The wafer separation and transfer method according to  claim 3 , comprising:
 a collecting step of collecting automatically collecting the carried wafer in the carrying step in a wafer collection box; and   a subsequent step transfer step of automatically transferring the wafer collection box after collected to a subsequent step using a multi-robot arm.   
     
     
         10 . The solar cell wafer separation and transfer method according to  claim 4 , comprising:
 a collecting step of collecting automatically collecting the carried wafer in the carrying step in a wafer collection box; and   a subsequent step transfer step of automatically transferring the wafer collection box after collected to a subsequent step using a multi-robot arm.   
     
     
         11 . The wafer separation and transfer method according to  claim 2 ,
 wherein in the micro bubble issuing step, the nozzle or the cassette support is moved along a direction of arranging the wafers.   
     
     
         12 . The solar cell wafer separation and transfer method according to  claim 4 ,
 wherein in the micro bubble issuing step, the nozzle or the cassette support is moved along a direction of arranging the wafers.   
     
     
         13 . The solar cell wafer separation and transfer method according to  claim 5 ,
 wherein in the micro bubble issuing step, the nozzle or the cassette support is moved along a direction of arranging the wafers.   
     
     
         14 . The wafer separation and transfer method according to  claim 12 ,
 wherein before starting the micro bubble issuing step, five sides except the underside of the cassette support is covered with a cover as the cassette support is immersed in the inside of the liquid bath.   
     
     
         15 . The wafer separation and transfer method according to  claim 3 ,
 wherein before starting the micro bubble issuing step, five sides except the underside of the cassette support is covered with a cover as the cassette support is immersed in the inside of the liquid bath.   
     
     
         16 . The solar cell wafer separation and transfer method according to  claim 4 ,
 wherein before starting the micro bubble issuing step, five sides except the underside of the cassette support is covered with a cover as the cassette support is immersed in the inside of the liquid bath.