Wet etching apparatus

Abstract

A wet etching apparatus includes a process bath having an internal space configured to receive an etchant and having a support unit, on which a wafer is disposed to be in contact with the etchant. A laser unit is disposed above the process bath and is configured to direct a laser beam to the wafer and to heat the wafer thereby. An etchant supply unit is configured to supply the etchant to the internal space of the process bath.

1 . A wet etching apparatus, comprising:
 a process bath having an internal space configured to receive an etchant and having a support unit, on which a wafer is disposed to be in contact with the etchant;   a laser unit disposed above the process bath and configured to direct a laser beam to the wafer and to heat the wafer thereby; and   an etchant supply unit configured to supply the etchant to the internal space of the process bath.   
     
     
         2 . The wet etching apparatus of  claim 1 , wherein the laser unit comprises a laser light source configured to emit the laser beam and an optical system disposed between the laser light source and the process bath and configured to expand an area of the laser beam. 
     
     
         3 . The wet etching apparatus of  claim 2 , wherein the area of the laser beam expanded by the optical system has an area large enough to cover an area of the wafer. 
     
     
         4 . The wet etching apparatus of  claim 1 , wherein the laser unit comprises a laser light source emitting a line-type laser beam and a scanning unit moving the laser beam, such that the wafer is irradiated. 
     
     
         5 . The wet etching apparatus of  claim 1 , further comprising a housing having a closed space in which the laser unit is disposed, the closed space being configured to be depressurized or maintained in a vacuum state. 
     
     
         6 . The wet etching apparatus of  claim 1 , wherein the support unit is disposed in the internal space of the process bath and is configured to immerse the wafer in the etchant, and
 wherein the process bath comprises a transparent window through which the laser beam passes to the wafer disposed on the support unit.   
     
     
         7 . The wet etching apparatus of  claim 6 , wherein the surface to be treated of the wafer faces upward, and the laser beam is cast onto the surface to be treated of the wafer. 
     
     
         8 . The wet etching apparatus of  claim 6 , wherein the process bath has an inlet configured to open and close the internal space of the process bath. 
     
     
         9 . The wet etching apparatus of  claim 1 , wherein the support unit comprises an opening disposed at an upper portion of the process bath and recessed into the internal space and a supporting part disposed around the opening and supporting an outer peripheral portion of the wafer. 
     
     
         10 . The wet etching apparatus of  claim 9 , wherein the surface to be treated of the wafer is directed to the internal space, and the laser beam irradiates a surface located opposite to the surface to be treated of the wafer. 
     
     
         11 . The wet etching apparatus of  claim 9 , wherein the wafer and the supporting part are brought into contact with each other such that the wafer closes the opening, while the surface to be treated of the wafer is in contact with the etchant. 
     
     
         12 . The wet etching apparatus of  claim 1 , wherein the etchant supply unit supplies the etchant at a flow rate in a range of 0.1 to 1.0 m/sec. 
     
     
         13 . The wet etching apparatus of  claim 1 , wherein the etchant supply unit comprises an etchant injection unit disposed on a first side of the process bath and configured to inject the etchant into the internal space of the process bath, and an etchant discharge unit disposed on a second side of the process bath and configured to discharge the etchant from the internal space of the process bath. 
     
     
         14 . The wet etching apparatus of  claim 13 , further comprising an etchant circulation unit connected to the etchant injection unit and the etchant discharge unit and configured to circulate the etchant. 
     
     
         15 . The wet etching apparatus of  claim 1 , further comprising a concentration detecting unit configured to detect a concentration of the etchant and/or a concentration of an element to be etched. 
     
     
         16 . The wet etching apparatus of  claim 15 , wherein the etchant is a phosphoric acid, and the element to be etched comprises silicon Si. 
     
     
         17 . (canceled) 
     
     
         18 . A wet etching apparatus, comprising:
 a process bath having an internal space configured to receive an etchant and having a support unit disposed therein, the support unit configured to support a wafer that is in contact with the etchant;   a laser unit disposed above the process bath and having a laser light source emitting a laser beam and an optical system expanding an area of the laser beam and configured to expose the wafer with the expanded laser beam; and   an etchant supply unit having an etchant injection unit and an etchant discharge unit respectively provided on sides opposite to the process bath, a pipe connecting the etchant injection unit and the etchant discharge unit, and a circulation pump mounted on the pipe.   
     
     
         19 . (canceled) 
     
     
         20 . The wet etching apparatus of  claim 18 , further comprising a first concentration detecting unit connected to the etchant discharge unit or the pipe and configured to detect the concentration of the element to be etched discharged from the process bath, and an etchant storage unit connected to the etchant supply unit and configured to supply a pure etchant according to the concentration of the detected element to be etched. 
     
     
         21 . The wet etching apparatus of  claim 18 , further comprising a second concentration detecting unit connected to the etchant discharge unit or the pipe and configured to detect the concentration of the etchant discharged from the process bath, and a deionized water storage unit connected to the etchant supply unit and supplying deionized water, to the etchant according to the concentration of the detected etchant. 
     
     
         22 . A wet etching apparatus, comprising:
 a process bath having an internal space configured to receive an etchant and including an opening and recessed into the internal space, and a supporting part disposed around the opening and supporting an outer peripheral portion of the wafer, the wafer disposed on the supporting part in contact with the etchant;   a laser unit disposed above the process bath and casting a laser beam onto a surface opposite to the surface to be treated of the wafer such that the wafer is heated;   an etchant supply unit configured to supply the etchant to the internal space of the process bath; and   a discharge unit configured to discharge the etchant from the internal space of the process.   
     
     
         23 - 24 . (canceled)