Local etching apparatus and local etching method

Abstract

A local etching apparatus and local etching method improving the throughput of the local etching apparatus by preheating a discharge tube before ignition of the plasma discharge. The local etching apparatus is provided with a plasma generator 1 , an alumina discharge tube 2 , and a heater 6 . The heater 6 is constituted by a heating wire 60 , a power source 61 for supplying voltage to the heating wire 60 , and a voltage regulator 62 for controlling the voltage supplied from the power source 61 to the heating wire 60. Due to this, it is possible to heat the alumina discharge tube 2 to the desired temperature by the heater 6 immediately before the plasma discharge by the plasma generator 1. As a result, there is no need to wait with the local etching work until the alumina discharge tube 2 rises in temperature to the desired temperature due to the heat by the plasma discharge, that is, it is possible to perform the local etching work immediately after the plasma discharge.

What is claimed is:  
     
         1 . A local etching apparatus comprising: 
 a discharge tube with a spray port of a nozzle portion facing an object to be etched in a chamber;    a plasma generator for causing plasma discharge of a predetermined gas in said discharge tube so as to produce radicals for locally etching a relatively thick portion present on a surface of the object to be etched; and    a heater for heating said discharge tube to a predetermined temperature.    
     
     
         2 . A local etching apparatus as set forth in    claim 1   , wherein said heater is provided with: 
 a heating member provided so as to surround said discharge tube and capable of raising the temperature in accordance with voltage applied thereto; and    a voltage controller for controlling the voltage applied to said heating member.    
     
     
         3 . A local etching apparatus as set forth in    claim 2   , wherein said heating member of said heater is a heating wire wound around said discharge tube.  
     
     
         4 . A local etching apparatus as set forth in    claim 1   , wherein said heater is an optical heater which emits infrared rays or a laser beam to said discharge tube to heat said discharge tube.  
     
     
         5 . A local etching apparatus as set forth in    claim 1   , wherein said heater is provided with: 
 a heating block arranged so as to surround said discharge tube in a state contacting the outer side of said discharge tube and has a fluid feed port and fluid exhaust port communicating with a fluid storage portion at the inside; and    a fluid feeder for heating the fluid to a predetermined temperature and feeding it to the fluid storage portion of said heating block.    
     
     
         6 . A local etching apparatus as set forth in    claim 5   , wherein said heating block of said heater is comprised of a thin tube wound around said discharge tube.  
     
     
         7 . A local etching apparatus as set forth in any one of    claims 1    to    6   , wherein said discharge tube used is any one of an alumina discharge tube, an aluminum nitride discharge tube, a sapphire discharge tube, and a quartz discharge tube.  
     
     
         8 . A local etching method comprising: 
 a plasma generating step for causing plasma discharge of a predetermined gas in a discharge tube so as to produce radicals and spraying the radicals from a nozzle portion of the discharge tube;    a local etching step for locally etching a relatively thick portion present on the surface of the object to be etched by the radicals sprayed from the nozzle portion while making the nozzle portion of the discharge tube move relatively along the surface of the object to be etched; and    a heating step for heating the discharge tube at least to a time of start of plasma discharge of said plasma generating step to at least a temperature at which the etching depth of the object to be etched at said local etching step becomes substantially constant.    
     
     
         9 . A local etching method as set forth in    claim 8   , wherein said heating step is comprised of heating the discharge tube to the temperature at all times.  
     
     
         10 . A local etching method as set forth in    claim 8   , wherein said heating step is comprised of heating the discharge tube to the temperature until the start of plasma discharge of said plasma generating step.  
     
     
         11 . A local etching method as set forth in any one of    claims 8    to    10   , wherein said heating step is comprised of heating a location of the discharge tube between the plasma discharge location and the spray port of the discharge tube to the temperature.  
     
     
         12 . A local etching method as set forth in any one of    claims 8    to    11   , wherein said heating step is comprised of raising a temperature of a heating member surrounding the discharge tube by application of voltage so as to heat the discharge tube to the temperature.  
     
     
         13 . A local etching method as set forth in any one of    claims 8    to    11   , wherein said heating step is comprised of emitting infrared rays or a laser beam to the discharge tube to heat the discharge tube to the temperature.  
     
     
         14 . A local etching method as set forth in any of    claims 8    to    11   , wherein said heating step is comprised of feeding a heated fluid into a heating block arranged so as to surround the discharge tube in a state contacting the outer side of the discharge tube so as to heat the discharge tube to the temperature.