Processing apparatus and method for processing metal film

Abstract

A method for processing a metal film includes adiabatically expanding a mixed gas including an oxidation gas, a complexing gas and a rare gas in a processing chamber having a vacuum exhaust device such that a gas cluster beam is generated in the processing chamber, and irradiating the gas cluster beam upon a metal film formed on a surface of a workpiece in the processing chamber such that the gas cluster beam collides on the metal film including a metal element and the metal film is etched. The mixed gas includes the oxidation gas which oxidizes the metal element and forms an oxide, and the complexing gas which reacts with the oxide and forms an organometallic complex

What is claimed is: 
     
         1 . A method for processing a metal film, comprising:
 adiabatically expanding a mixed gas comprising an oxidation gas, a complexing gas and a rare gas in a processing chamber having a vacuum exhaust device such that a gas cluster beam is generated in the processing chamber; and   irradiating the gas cluster beam upon a metal film formed on a surface of a workpiece in the processing chamber such that the gas cluster beam collides on the metal film comprising a metal element and the metal film is etched,   wherein the mixed gas includes the oxidation gas which oxidizes the metal element and forms an oxide, and the complexing gas which reacts with the oxide and forms an organometallic complex.   
     
     
         2 . The method for processing a metal film according to  claim 1 , wherein the oxidation gas is at least one gas selected from the group consisting of O 2 , H 2 O and H 2 O 2 . 
     
     
         3 . The method for processing a metal film according to  claim 1 , wherein the complexing gas is at least one gas selected from the group consisting of acetylacetone, hexafluoroacetylacetone, trifluoroacetic acid, formic acid, acetic acid, propionic acid, butyric acid and valeric acid. 
     
     
         4 . The method for processing a metal film according to  claim 1 , wherein the irradiating of the gas cluster beam includes ionizing and accelerating the gas cluster beam. 
     
     
         5 . The method for processing a metal film according to  claim 1 , wherein the mixed gas has the oxidation gas in an amount which is set less than an amount of complexing gas. 
     
     
         6 . The method for processing a metal film according to  claim 1 , further comprising forming a patterned mask on a surface of the metal film, wherein the gas cluster beam etches the metal film through the patterned mask. 
     
     
         7 . The method for processing a metal film according to  claim 1 , wherein the metal element is a metal selected from a group of Cu, Co, Ni, Pt and Ru. 
     
     
         8 . A processing apparatus for etching a metal film, comprising:
 a processing chamber having a vacuum exhaust device;   a holding device configured to hold a workpiece;   a gas cluster beam generating device positioned to face the holding device and configured to generate a gas cluster beam through adiabatic expansion of a mixed gas comprising an oxidation gas which oxidizes a metal element and forms an oxide, a complexing gas which reacts with the oxide and forms an organometallic complex, and a rare gas; and   a gas cluster beam irradiation device configured to irradiate the gas cluster beam onto a metal film comprising the metal element formed on a surface of the workpiece.   
     
     
         9 . The processing apparatus for etching a metal film according to  claim 8 , wherein the gas cluster beam irradiation device includes a nozzle configured to irradiate the gas cluster beam, and a skimming plate facing the nozzle and positioned between the nozzle and the workpiece, and the skimming plate has a gas skimming aperture configured to selectively pass a beam emitting in a selected direction in the gas cluster beam. 
     
     
         10 . The processing apparatus for etching a metal film according to  claim 9 , further comprising:
 an ionizer configured to ionize the gas cluster beam; and   an acceleration electrode configured to accelerate the gas cluster beam ionized by the ionizer.   
     
     
         11 . The processing apparatus for etching metal film according to  claim 10 , further comprising a partition positioned parallel to the skimming plate between the skimming plate and the workpiece, wherein the ionizer and the accelerator are positioned in an ionization space formed by the partition and the skimming plate, and the partition has an irradiation aperture configured to irradiate onto the workipiece the gas cluster beam ionized and accelerated in the ionization space. 
     
     
         12 . The processing apparatus for etching a metal film according to  claim 8 , wherein the oxidation gas is at least one gas selected from the group consisting of O 2 , H 2 O and H 2 O 2 . 
     
     
         13 . The processing apparatus for etching metal film according to  claim 8 , wherein the complexing gas is at least one gas selected from the group consisting of acetylacetone, hexafluoroacetylacetone, trifluoroacetic acid, formic acid, acetic acid, propionic acid, butyric acid and valeric acid. 
     
     
         14 . The processing apparatus for etching a metal film according to  claim 8 , wherein the gas cluster beam generating device is configured to generate the gas cluster beam from the mixed gas in which the oxidation gas has an amount set less than an amount of complexing gas. 
     
     
         15 . The processing apparatus for etching metal film according to  claim 8 , wherein the workpiece has a patterned mask for etching formed on a surface of the metal film. 
     
     
         16 . The processing apparatus for etching a metal film according to  claim 8 , wherein the metal element is a metal selected from the group consisting of Cu, Co, Ni, Pt and Ru. 
     
     
         17 . The processing apparatus for etching a metal film according to  claim 8 , further comprising:
 an ionizer configured to ionize the gas cluster beam; and   an acceleration electrode configured to accelerate the gas cluster beam ionized by the ionizer.