Apparatus for etching semiconductor samples and a source for providing a gas by sublimation thereto

Abstract

An etching apparatus for etching semi combustion samples may include one or more variable volume expansion chambers, two or more fixed volume expansion chambers, or combinations thereof in fluid communication with an etching chamber and a source of etching gas, such as xenon difluoride. The apparatus may further include a source of a mixing gas. An etching apparatus may also include a source of etching gas, an etching chamber in fluid communication with the source of etching gas, a flow controller connected between the source of etching gas and the etching chamber, and a vacuum pump in fluid communication with the etching chamber. A source for providing a gas by sublimation from a solid material is also provided, including a vacuum tight container and a mesh mounted in the interior of the vacuum tight container, wherein the mesh is adapted to receive and restrain the solid material.

1 - 13 . (canceled)  
   
   
       14 . A method of etching a sample held in an etching chamber at a desired etch pressure, comprising the steps of: 
 setting a volume of a collapsible, variable volume expansion chamber to an initial volume and feeding an etching gas into said expansion chamber from a source having a source pressure;    placing said expansion chamber in fluid communication with said etching chamber;    collapsing said expansion chamber; and    maintaining said expansion chamber and said etching chamber at temperatures at which said etching gas will not solidify at said etch pressure.    
   
   
       15 . A method according to  claim 14 , wherein said initial volume is determined by multiplying a volume of said etching chamber by said etch pressure and dividing a result of said multiplication by said source pressure  
   
   
       16 . A method according to  claim 14 , further comprising the steps of: 
 removing said expansion chamber from fluid communication with said etching chamber after said collapsing step;    repeating said setting and feeding steps;    determining that an etch process taking place in said etching chamber is complete;    evacuating said etching chamber after said determining step; and    repeating said placing and collapsing steps after said evacuating step.    
   
   
       17 . A method according to  claim 16 , wherein said determining step comprises determining that an etch time has elapsed.  
   
   
       18 . A method according to  claim 16 , wherein said determining step comprises analyzing gasses drawn from said said etching chamber and determining that said etch process is complete when the concentrations of one or more elements or compounds reaches a preset value.  
   
   
       19 . A method according to  claim 14 , wherein said etching gas comprises xenon difluoride.  
   
   
       20 . A method according to  claim 14 , wherein said feeding step further comprises feeding a mixing gas into said expansion chamber from a source of mixing gas, said source of mixing gas being at said source pressure.  
   
   
       21 . A method according to  claim 20 , wherein said mixing gas comprises nitrogen.  
   
   
       22 . A method according to  claim 20 , wherein said feeding step continues until a pressure inside said expansion chamber equals a predetermined set point pressure.  
   
   
       23 . A method according to  claim 14 , wherein said feeding step continues until a pressure inside said expansion chamber equals a predetermined set point pressure.  
   
   
       24 . A method according to  claim 16 , further comprising the step of evacuating said expansion chamber before said feeding step.  
   
   
       25 - 47 . (canceled)  
   
   
       48 . An etching apparatus, comprising: 
 a source of etching gas;    an etching chamber in selective fluid communication with said source of etching gas;    a flow controller connected between said source of etching gas and said etching chamber; and    a vacuum pump in selective fluid communication with said etching chamber.    
   
   
       49 . An etching apparatus according to  claim 48 , wherein said etching gas comprises xenon difluoride.  
   
   
       50 . An etching apparatus according to  claim 48 , further comprising a source of mixing gas in selective fluid communication with said etching chamber and a second flow controller connected between said source of mixing gas and said etching chamber.  
   
   
       51 . An etching apparatus according to  claim 50 , wherein said mixing gas comprises nitrogen.  
   
   
       52 . An etching apparatus according to  claim 48 , wherein said source of etching gas comprises a vacuum tight container having a mesh mounted in the interior thereof, said mesh being adapted to hold a solid material used to generate said etching gas.  
   
   
       53 . An etching apparatus according to  claim 52 , where said etching gas comprises xenon difluoride, said solid material comprises xenon difluoride crystals, and said etching gas is generated through sublimation.  
   
   
       54 . An etching apparatus according to  claim 52 , wherein said mesh has a W-shaped cross section.  
   
   
       55 . An etching apparatus according to  claim 54 , wherein said vacuum tight container has a cylindrical shape.  
   
   
       56 . An etching apparatus according to  claim 55 , wherein said vacuum tight container comprises a standard gas cylinder.  
   
   
       57 . An etching apparatus according to  claim 52 , wherein said mesh comprises a material chosen from the group of consisting of aluminum, stainless steel and Teflon.  
   
   
       58 . An etching apparatus according to  claim 53 , said mesh having a plurality of openings, each of said openings being sized to be smaller than an average size of said xenon difluoride crystals.  
   
   
       59 . A source for providing a gas by sublimation from a solid material, comprising: 
 a vacuum tight container; and    a mesh mounted in the interior of said vacuum tight container, said mesh being adapted to receive and restrain said solid material.    
   
   
       60 . A source according to  claim 59 , wherein said mesh has a W-shaped cross section.  
   
   
       61 . A source according to  claim 59 , wherein said mesh has a WW-shaped cross section.  
   
   
       62 . A source according to  claim 59 , wherein said vacuum tight container has a cylindrical shape.  
   
   
       63 . A source according to  claim 62 , wherein said vacuum tight container comprises a standard gas cylinder.  
   
   
       64 . A source according to  claim 59 , wherein said mesh comprises a material chosen from the group consisting of aluminum, stainless steel and Teflon.  
   
   
       65 . A source for providing an etching gas to an etching apparatus by sublimation from a solid material, comprising: 
 a vacuum tight container; and    a mesh mounted in the interior of said vacuum tight container, said mesh being adapted to receive and restrain said solid material.    
   
   
       66 . A source according to  claim 65 , wherein said etching gas comprises xenon difluoride and said solid material comprises xenon difluoride crystals.  
   
   
       67 . A source according to  claim 65 , wherein said mesh has a W-shaped cross section.  
   
   
       68 . A source according to  claim 65 , wherein said mesh has a WW-shaped cross section.  
   
   
       69 . A source according to  claim 65 , wherein said vacuum tight container has a cylindrical shape.  
   
   
       70 . A source according to  claim 69 , wherein said vacuum tight container comprises a standard gas cylinder.  
   
   
       71 . A source according to  claim 65 , wherein said mesh comprises a material chosen from the group consisting of aluminum, stainless steel and Teflon.