Reactive ion etching of silica structures

Abstract

The invention relates to a method for etching of silica-based layers/substrates by reactive ion etching system ( 10 ) using an etching gas mixture of CHF 3 /AR through a photoresist mask. Reactive ion etching is carried out under conditions of simultaneous isotropic deposition of a carbon-based polymer where the polymer deposition rate is controlled by adjusting process control parameters of RF power, sample temperature, O 2 and CF 4 additions.

We claim:  
     
         1 . A method for etching of silica-based glass layers or substrates comprising reactive ion etching through a mask executed under conditions of simultaneous isotropic deposition of a carbon based polymer.  
     
     
         2 . The method of  claim 1  wherein the polymer deposition rate or/and its steady-state thickness on different surfaces of the etched structure is controlled by adjusting one or several process control parameters in order to control etched profile, dimension loss, sidewall and bottom etched surface roughness, and etching selectivity between the silica-based layer and mask material.  
     
     
         3 . The method of any previous claim wherein gas or a mixture of gases is used, which contain fluorine and carbon atoms.  
     
     
         4 . The method of any previous claim wherein a photoresist mask is used.  
     
     
         5 . The method of  claims 1  to  3  wherein a non-photoresist mask is used.  
     
     
         6 . The method of  claim 5  wherein amorphous silicon is the mask material.  
     
     
         7 . The method of any previous claim wherein the Rf power coupled into the discharge is the adjusted parameter.  
     
     
         8 . The method of any previous claim wherein the substrate temperature is the adjusted parameter.  
     
     
         9 . The method of  claim 8  where the temperature is adjusted to achieve low sidewall roughness and low dimension loss at the same time.  
     
     
         10 . The method of any previous claim wherein a resputtering of any metal present wihtin or/and in contact with the discharge zone is prevented.  
     
     
         11 . The method of any previous claim wherein reactive ion etching is performed in a high plasma density hollow cathode etching system.  
     
     
         12 . The method of any previous claim wherein the etching gas mixture is CH 3 F and Argon.  
     
     
         13 . A product made by the method of any previous claim.