Method providing an improved bi-layer photoresist pattern

Abstract

A method for etching a feature in a layer is provided. An underlayer of a polymer material is formed over the layer. A top image layer is formed over the underlayer. The top image layer is exposed to patterned radiation. A pattern is developed in the top image layer. The pattern is transferred from the top image layer to the underlayer with a reducing dry etch. The layer is etched through the underlayer, where the top image layer is completely removed and the underlayer is used as a pattern mask during the etching the layer to transfer the pattern from the underlayer to the layer.

1 - 21 . (canceled)  
   
   
       22 . An apparatus for etching a feature in an etch layer on a substrate, wherein the etch layer is disposed below an underlayer, which is disposed below a patterned polymer top image layer with silicon, wherein the patterned polymer top image layer has a higher silicon concentration than the underlayer, comprising: 
 a process chamber, within which the substrate may be placed;    a gas source, which is able to provide different gas chemistries to the process chamber;    a ionizing power source for generating a plasma from the gas chemistries;    a controller controllably connected to the gas source and ionizing power source, wherein the controller comprises computer readable media, comprising: 
 computer instructions for hardening the patterned polymer top image layer, comprising: 
 computer instructions for providing a hardening gas comprising oxygen, wherein a flow rate of oxygen is at least for 4% of a flow rate of the hardening gas;  
 computer instructions for energizing the hardening gas to create a hardening plasma; and  
 computer instructions for terminating the hardening the patterned polymer top image layer;  
 
 computer instructions for providing a reducing gas;  
 computer instructions for energizing the reducing gas to create a plasma for etching an underlayer;  
 computer instructions for terminating the etching of the underlayer;  
 computer instructions for providing an etch layer etchant; and  
 computer instructions for energizing the etch layer etchant to create a plasma for etching the etch layer.  
   
   
   
       23 . The apparatus, as recited in  claim 22 , wherein the reducing gas is oxygen free.  
   
   
       24 . The apparatus, as recited in  claim 23 , wherein the reducing gas comprises a nitrogen species and a hydrogen species.  
   
   
       25 . The apparatus, as recited in  claim 24 , wherein the reducing gas further comprises a hydrocarbon.  
   
   
       26 . The apparatus, as recited in  claim 25 , wherein the reducing gas further comprises a hydrofluorocarbon.  
   
   
       27 . The apparatus, as recited in  claim 26 , further comprising computer instructions for removing the underlayer.  
   
   
       28 . The apparatus, as recited in  claim 27 , wherein the computer instructions for energizing the hardening gas, comprises computer instructions for providing less than 500 Watts of bias power from the ionizing power source.  
   
   
       29 . The apparatus, as recited in  claim 27 , wherein the computer instructions for energizing the hardening gas, comprises computer instructions for providing no bias power from the ionizing power source.  
   
   
       30 . The apparatus, as recited in  claim 27 , wherein the computer instructions for hardening the patterned polymer top image layer causes silicon oxide to be formed in the patterned polymer top image layer.  
   
   
       31 . The apparatus, as recited in  claim 30 , wherein the computer instructions for hardening the patterned polymer top image layer does not form silicon oxide in the underlayer.  
   
   
       32 . The apparatus, as recited in  claim 22 , wherein the reducing gas comprises a nitrogen species and a hydrogen species.  
   
   
       33 . The apparatus, as recited in  claim 32 , wherein the reducing gas further comprises a hydrocarbon.  
   
   
       34 . The apparatus, as recited in  claim 33 , wherein the reducing gas further comprises a hydrofluorocarbon.  
   
   
       35 . The apparatus, as recited in  claim 22 , further comprising computer instructions for removing the underlayer.  
   
   
       36 . The apparatus, as recited in  claim 22 , wherein the computer instructions for energizing the hardening gas, comprises computer instructions for providing less than 500 Watts of bias power from the ionizing power source.  
   
   
       37 . The apparatus, as recited in  claim 22 , wherein the computer instructions for energizing the hardening gas, comprises computer instructions for providing no bias power from the ionizing power source.  
   
   
       38 . The apparatus, as recited in  claim 22 , wherein the computer instructions for hardening the patterned polymer top image layer causes silicon oxide to be formed in the patterned polymer top image layer.  
   
   
       39 . The apparatus, as recited in  claim 38 , wherein the computer instructions for hardening the patterned polymer top image layer does not form silicon oxide in the underlayer.