Substrate processing apparatus

Abstract

An SOI substrate which has a thick SOI layer is first prepared. Then, the SOI layer is thinned to a target film thickness using as a unit a predetermined thickness not more than that of one lattice. This thinning is performed by repeating a unit thinning step which includes an oxidation step of oxidizing the surface of the SOI layer by the predetermined thickness not more than that of one lattice and a removal step of selectively removing silicon oxide formed by the oxidation. The SOI layer of the SOI substrate is chemically etched by supplying a chemical solution to the SOI layer, and the film thickness of the etched SOI layer is measured. When the measured film thickness of the SOI layer has a predetermined value, a process of chemically etching the SOI layer ends.

1 . A substrate processing apparatus suitable for processing a substrate, which has a silicon layer on a insulating layer, the apparatus comprising: 
 an oxidizing agent supply mechanism, which supplies an oxidizing agent to the substrate to oxidize a surface of the silicon layer;    an etchant supply mechanism, which supplies to the substrate an etchant for selectively etching silicon oxide to selectively remove silicon oxide formed on the surface of the silicon layer; and    a controller, which controls the oxidizing agent supply mechanism and the etchant supply mechanism so as to repeat a unit thinning step of thinning the silicon layer by oxidizing the surface of the silicon layer to form the silicon oxide and selectively removing the silicon oxide.    
   
   
       2 . The apparatus according to  claim 1 , wherein the controller is configured to control repetition of the unit thinning step such that the silicon layer is thinned to a desired thickness.  
   
   
       3 . The apparatus according to  claim 1 , further comprising a measurement unit, which measures a thickness of the silicon layer, wherein the controller is configured to stop repeating the thinning step when it is determined on the basis of a measurement result from the measurement unit that the silicon layer is thinned to a desired thickness.  
   
   
       4 . The apparatus according to  claim 1 , further comprising a measurement unit, which measures a thickness of the silicon layer, 
 wherein the controller is configured to determine a repetition count of the thinning step required to thin the silicon layer to a desired thickness on the basis of a measurement result from the measurement unit.    
   
   
       5 . A substrate processing apparatus comprising: 
 an etching device, which chemically etches a semiconductor layer of a semiconductor substrate by supplying a chemical to the semiconductor layer;    a film thickness measurement device, which measures a thickness of the semiconductor layer; and    a control unit, which ends a process of chemically etching the semiconductor layer on the basis of a measurement result from the film thickness measurement device.    
   
   
       6 . A substrate processing apparatus comprising: 
 a holder, which holds a semiconductor substrate;    a chemical solution supply device, which has a nozzle arranged above the holder and supplies a chemical solution for chemically etching a semiconductor layer of the semiconductor substrate held by the holder from the nozzle to the semiconductor layer while an entire surface of the semiconductor layer is exposed;    a film thickness measurement device, which measures a film thickness of the semiconductor layer; and    a control unit, which ends a process of chemically etching the semiconductor layer on the basis of a measurement result from the film thickness measurement device.    
   
   
       7 . The apparatus according to  claim 5 , wherein the control unit has a mechanism, which stops a process of supplying a chemical to the semiconductor layer.  
   
   
       8 . The apparatus according to  claim 7 , wherein the control unit further comprises a mechanism, which supplies a rinse to the semiconductor layer.  
   
   
       9 . The apparatus according to  claim 8 , wherein the control unit further comprises a mechanism, which rotates the semiconductor substrate.  
   
   
       10 . The apparatus according to  claim 5 , wherein the film thickness measurement device comprises: 
 an irradiator, which irradiates a surface of the semiconductor layer with one of light, X-rays, and ultrasonic waves;    a measurement unit, which measures the one of light, X-rays, and ultrasonic waves reflected on the surface of the semiconductor layer; and    a converter, which converts a measurement result from the measurement unit into the film thickness of the semiconductor layer.    
   
   
       11 . The apparatus according to  claim 5 , wherein the film thickness measurement device comprises: 
 a measurement unit, which measures concentrations of components of the semiconductor layer contained in a chemical solution, which is used to etch the semiconductor layer; and    a converter, which converts a measurement result from the measurement unit into the film thickness of the semiconductor layer.    
   
   
       12 . The apparatus according to  claim 5 , wherein the film thickness measurement device comprises: 
 a measurement unit, which measures a weight of the semiconductor substrate; and    a converter, which converts a measurement result from the measurement unit into the film thickness of the semiconductor layer.    
   
   
       13 . The apparatus according to  claim 5 , further comprising a cover member arranged so as to surround a region in which the substrate is arranged.