Method for processing substrates

Abstract

A method for processing a substrate in a plasma chamber is provided. The method includes providing a substrate on which as underlying layer to be etched and a mask are formed. The method further includes forming a protective film on the mask. The method further includes performing as anisotropic deposition to selectively form a deposition layer on a top portion of the mask.

1 - 14 . (canceled) 
     
     
         15 . A plasma processing apparatus comprising:
 a chamber;   a stage to hold a substrate in the chamber, the substrate having an extreme ultraviolet (EUV) mask disposed on an underlying layer;   a controllable gas supply that supplies a process gas to the chamber at a predetermined rate; and   an plasma generator that generates plasma from the process gas to expose the substrate to the plasma in a balanced plasma process, the balanced plasma process including simultaneous deposition and etching of the EUV mask, wherein   the process gas includes
 a deposition gas containing C x H y F z , where (i) x is a natural number not less than one, y is a natural number not less than one, and z is zero or a natural number not less than one, or (ii) x is a natural number not less than one, y is zero or a natural number not less than one, and z is a natural number not less than one, and 
 an etching gas containing at least one of N 2 , O 2 , and H 2 , 
   wherein the predetermined rate is determined such that resulting etching and resulting deposition are performed simultaneously in the balanced plasma process, and the resulting etching of the EUV mask is offset by the resulting deposition in the balanced plasma process.   
     
     
         16 . The plasma processing apparatus of  claim 15 , wherein
 the controllable gas supply and the plasma generator are configured to etch the underlying layer after completion of the balanced plasma process.   
     
     
         17 . The plasma processing apparatus of  claim 16 , wherein
 the underlying layer is etched in the chamber.   
     
     
         18 . The plasma process apparatus of  claim 16 , wherein the controllable gas supply and plasma generator are configured to control the balanced plasma process so that a Local Critical Dimension Uniformity (LCDU (3σ)) of the EUV mask after the balanced plasma process and etching of the underlying layer is smaller than a LCDU (3σ) of the EUV mask after the forming of the EUV mask but before execution of the balanced plasma process. 
     
     
         19 . The plasma process apparatus of  claim 15 , wherein the process gas includes CH 4  and N 2 . 
     
     
         20 . The plasma process apparatus of  claim 15 , wherein the controllable gas supply and the plasma generator are configured to form a protective film after the completion of the balanced plasma process. 
     
     
         21 . The plasma processing apparatus of  claim 15 , further comprising an upper electrode and a lower electrode in the chamber, wherein the lower electrode includes an electrostatic chuck to support and retain the substrate. 
     
     
         22 . The plasma processing apparatus of  claim 21 , wherein the plasma generator is coupled to at least one of the upper electrode or the lower electrode. 
     
     
         23 . The plasma processing apparatus of  claim 21 , wherein a variable direct current power supply is coupled to the upper electrode. 
     
     
         24 . The plasma processing apparatus of  claim 15 , further comprising a dielectric window, an inductive element disposed above the dielectric winder, and a lower electrode, wherein the lower electrode includes an electrostatic chuck to support and retain the substrate. 
     
     
         25 . The plasma processing apparatus of  claim 24 , wherein the plasma generator is coupled to at least one of the inductive element or the lower electrode. 
     
     
         26 . The plasma processing apparatus of  claim 15 , further comprising an exhauster to evacuate the chamber. 
     
     
         27 . The plasma processing apparatus of  claim 26 , wherein the exhauster includes a turbo molecular pump. 
     
     
         28 . The plasma processing apparatus of  claim 16 , wherein the underlying layer is etched in another chamber. 
     
     
         29 . The plasma processing apparatus of  claim 15 , wherein a layer is formed on a top portion of the EUV mask, but not on a bottom portion or a sidewall portion of a pattern of the EUV mask on the substrate during the balanced plasma process. 
     
     
         30 . The plasma processing apparatus of  claim 29 , wherein the layer includes carbon 
     
     
         31 . The plasma processing apparatus of  claim 15 , wherein the substrate is a silicon substrate. 
     
     
         32 . The plasma processing apparatus of  claim 15 , wherein the EUV mask is an organic photoresist mask. 
     
     
         33 . The plasma processing apparatus of  claim 32 , wherein the EUV mask further includes tungsten or titanium. 
     
     
         34 . The plasma processing apparatus of  claim 15 , wherein the underlying layer includes oxides, metals or metal oxides, conductive films, dielectric materials, or hardmask materials.