Method for plasma etching performance enhancement

Abstract

A method for etching a feature in a layer through an etching mask is provided. A protective layer is formed on exposed surfaces of the etching mask and vertical sidewalls of the feature with a passivation gas mixture. The feature is etched through the etching mask with reactive etching mixtures containing at least one etching chemical and at least one passivation chemical.

1 - 19 . (Canceled).  
     
     
         20 . An apparatus for etching a single layer under an etch mask, wherein the single layer is supported by a substrate, comprising: 
 a plasma processing chamber, comprising: 
 a chamber wall forming a plasma processing chamber enclosure;  
 a substrate support for supporting a substrate within the plasma processing chamber enclosure;  
 a pressure regulator for regulating the pressure in the plasma processing chamber enclosure;  
 at least one electrode for providing power to the plasma processing chamber enclosure for sustaining a plasma;  
 a gas inlet for providing gas into the plasma processing chamber enclosure; and  
 a gas outlet for exhausting gas from the plasma processing chamber enclosure;  
   a deposition gas source;    an etchant gas source;    a first control valve in fluid connection between the gas inlet of the plasma processing chamber and the deposition gas source;    a second control valve in fluid connection between the gas inlet of the plasma processing chamber and the etchant gas source;    a controller controllably connected to the first control valve, the second control valve, and the at least one electrode, comprising: 
 at least one processor; and  
 computer readable media, comprising: 
 computer readable code for opening the first control valve for at least one deposition step to provide a deposition gas from the deposition gas source to the plasma processing chamber enclosure;  
 computer readable code for closing the second control valve for the at least one deposition step to prevent etching gas from the etchant gas source from entering the plasma processing chamber enclosure;  
 computer readable code for opening the second control valve for at least one etching step to provide an etching gas from the etchant gas source to the plasma processing chamber; and  
 computer readable code energizing the at least one electrode to provide a bias of greater than 250 volts on the substrate for the at least one etching step.  
 
   
     
     
         21 . The apparatus, as recited in  claim 20 , further comprising: 
 a passivation gas source; and    a third control valve in fluid connection between the gas inlet of the plasma processing chamber and the passivation gas source, wherein the third control valve is controllably connected to the controller,    wherein the computer readable media further comprises computer readable code for opening a third control valve for the at least one etching step to provide passivation gas from the passivation gas source to the plasma processing chamber.    
     
     
         22 . The apparatus, as recited in claim  19 , wherein the computer readable media further comprises computer readable code for performing the at least one deposition step and at least one etching step in an alternating fashion for a plurality of times.  
     
     
         23 . The apparatus, as recited in claim  19 , wherein the computer readable media further comprises computer readable code for determining whether etching of the single layer is completed.  
     
     
         24 . The apparatus, as recited in  claim 23 , wherein the computer readable media further comprises computer readable code for repeating the steps of opening the first control valve for at least one deposition step to provide a deposition gas from the deposition gas source to the plasma processing chamber enclosure, closing the second control valve for the at least one deposition step to prevent etching gas from the etchant gas source from entering the plasma processing chamber enclosure, opening the second control valve for at least one etching step to provide an etching gas from the etchant gas source to the plasma processing chamber, and energizing the at least one electrode to provide a bias of greater than 250 volts on the substrate for the at least one etching step until it is determined that the etching of the single layer is completed.  
     
     
         25 . An apparatus for etching a feature in a single layer under an etch mask, wherein the layer is supported by a substrate, comprising: 
 a plasma processing chamber, comprising: 
 a chamber wall forming a plasma processing chamber enclosure;  
 a substrate support for supporting a substrate within the plasma processing chamber enclosure;  
 a pressure regulator for regulating the pressure in the plasma processing chamber enclosure;  
 at least one electrode for providing power to the plasma processing chamber enclosure for sustaining a plasma;  
 a gas inlet for providing gas into the plasma processing chamber enclosure; and  
 a gas outlet for exhausting gas from the plasma processing chamber enclosure;  
   a deposition gas source;    an etchant gas source;    a first control valve in fluid connection between the gas inlet of the plasma processing chamber and the deposition gas source;    a second control valve in fluid connection between the gas inlet of the plasma processing chamber and the etchant gas source;    a controller controllably connected to the first control valve, the second control valve, and the at least one electrode, comprising: 
 at least one processor; and  
 computer readable media, comprising: 
 computer readable code for forming a protective coating on exposed surfaces of the etch mask and vertical sidewalls of the feature with a passivation gas mixture, wherein the forming the protective coating provides no protective coating on a bottom of the feature; and  
 computer readable code for etching the feature through the etching mask with reactive etching mixtures containing at least one etching chemical and at least one passivation chemical.  
 
   
     
     
         26 . The apparatus, as recited in  claim 25 , wherein the computer readable media further comprises computer readable code for determining whether etching of the single layer is completed.  
     
     
         27 . The apparatus, as recited in  claim 26 , wherein the computer readable media further comprises computer readable code for repeating the steps of forming the protective coating and etching the feature until it is determined that the etching of the single layer is completed.  
     
     
         28 . The apparatus, as recited in  claim 27 , wherein the computer readable code for forming the protective coating comprises computer readable code for selectively forming polymer on exposed areas and not on the bottom of the feature.  
     
     
         29 . The apparatus, as recited in  claim 28 , wherein the computer readable code for forming the protective coating comprises computer readable code for forming a protective coating that is more etch resistant than the etch mask.  
     
     
         30 . The apparatus, as recited in  claim 29 , wherein the computer readable code for forming the protective layer, comprises computer readable code for forming a polymer layer.  
     
     
         31 . The apparatus, as recited in  claim 25 , wherein the computer readable code for forming the protective coating comprises computer readable code for selectively forming polymer on exposed areas and not on the bottom of the feature.  
     
     
         32 . The apparatus, as recited in  claim 25 , wherein the computer readable code for forming the protective coating comprises computer readable code for forming a protective coating that is more etch resistant than the etch mask.  
     
     
         33 . The apparatus, as recited in  claim 25 , wherein the computer readable code for forming the protective layer, comprises computer readable code for forming a polymer layer.  
     
     
         34 . A computer readable media for use in a controller for an apparatus for etching a feature in a single layer under an etch mask, wherein the single layer is supported by a substrate, wherein the apparatus comprises a plasma processing chamber, comprising a chamber wall forming a plasma processing chamber enclosure, a substrate support for supporting a substrate within the plasma processing chamber enclosure, a pressure regulator for regulating the pressure in the plasma processing chamber enclosure, at least one electrode for providing power to the plasma processing chamber enclosure for sustaining a plasma, a gas inlet for providing gas into the plasma processing chamber enclosure, and a gas outlet for exhausting gas from the plasma processing chamber enclosure, a deposition gas source and an etchant gas source, comprising 
 computer readable code for forming a protective coating on exposed surfaces of the etch mask and vertical sidewalls of the feature with a passivation gas mixture, wherein the forming the protective coating provides no protective coating on a bottom of the feature; and    computer readable code for etching the feature through the etching mask with reactive etching mixtures containing at least one etching chemical and at least one passivation chemical.    
     
     
         35 . The computer readable media of  claim 34 , further comprising computer readable code for determining whether etching of the single layer is completed.  
     
     
         36 . The computer readable media of  claim 35 , further comprising computer readable code for repeating the steps of forming the protective coating and etching the feature until it is determined that the etching of the single layer is completed.  
     
     
         37 . The computer readable media of  claim 34 , wherein the computer readable code for forming the protective coating comprises computer readable code for selectively forming polymer on exposed areas and not on the bottom of the feature.  
     
     
         38 . The computer readable media of  claim 34 , wherein the computer readable code for forming the protective coating comprises computer readable code for forming a protective coating that is more etch resistant than the etch mask.  
     
     
         39 . The computer readable media of  claim 34 , wherein the computer readable code for forming the protective layer, comprises computer readable code for forming a polymer layer.