Oxygen plasma treatment for a nitride surface to reduce photo footing

Abstract

The present invention includes a method for preventing distortion in semiconductor fabrication. The method comprises providing a substrate comprising a film comprising silicon nitride. The substrate is treated in a vacuum of about 3.0-6.5 Torr in an atmosphere comprising oxygen plasma wherein the oxygen plasma flow rate is at least about 300 sccm oxygen. A resist is applied to the treated substrate and the resist is patterned over the treated substrate.

1 . An in-process semiconductor comprising: 
 a layer of silicon-nitride, wherein the silicon-nitride is tempered by treating the layer of silicon-nitride with an oxygen plasma in a vacuum of about 3.0-6.5 Torr; and    a patterned layer of photo resist positioned on the layer of silicon-nitride, wherein a vertical edge of the patterned layer of photo resist is substantially free from footing and undercutting profile distortions.    
   
   
       2 . The semiconductor of  claim 1  wherein the tempered silicon-nitride film is substantially free from surface viscosity discontinuities.  
   
   
       3 . The semiconductor of  claim 1  wherein the photo resist is an acid-catalyzed photo resist.  
   
   
       4 . The semiconductor of  claim 1  wherein the silicon-nitride is tempered by treating the layer of silicon-nitride in the vacuum for a time of about 10 seconds to about 5 minutes, and in an atmosphere free of argon and comprising the oxygen plasma as the gas present in the greatest concentration, wherein the oxygen plasma flow rate is at least about 300 sccm oxygen.  
   
   
       5 . The semiconductor of  claim 1  wherein the silicon-nitride is tempered by treating the layer of silicon-nitride in the vacuum for a time of about 10 seconds to about 5 minutes, and in an atmosphere consisting essentially of the oxygen plasma as the gas present in the greatest concentration, wherein the oxygen plasma is maintained at an oxygen flow rate of at least about 300 sccm oxygen to about 2000 sccm oxygen and a helium flow rate of about 400 to 1000 sccm helium.  
   
   
       6 . The semiconductor of  claim 1  wherein the oxygen plasma is made by an exposure to oxygen gas to microwave energy.  
   
   
       7 . The semiconductor of  claim 1  wherein the oxygen plasma is made by exposing oxygen gas to RF energy of about 150-900 watts.  
   
   
       8 . An in-process semiconductor device comprising: 
 a layer of silicon-nitride, wherein the silicon-nitride is tempered by treating the layer of silicon-nitride with an oxygen plasma in a vacuum of about 3.0-6.5 Torr; and    a layer of photo resist positioned on the layer of silicon-nitride, wherein photo resist is patterned with a UV lithography and vertical edges of the patterned layer of photo resist are substantially free of profile distortions.    
   
   
       9 . The semiconductor device of  claim 8  wherein the photo resist is an acid-catalyzed photo resist.  
   
   
       10 . The semiconductor device of  claim 8  wherein the silicon-nitride is tempered by treating the layer of silicon-nitride in the vacuum for a time of about 10 seconds to about 5 minutes, and in an atmosphere free of argon and comprising the oxygen plasma as the gas present in the greatest concentration, wherein the oxygen plasma flow rate is at least about 300 sccm oxygen.  
   
   
       11 . The semiconductor device of  claim 8  wherein the silicon-nitride is tempered by treating the layer of silicon-nitride in the vacuum for a time of about 10 seconds to about 5 minutes, and in an atmosphere consisting essentially of the oxygen plasma as the gas present in the greatest concentration, wherein the oxygen plasma is maintained at an oxygen flow rate of at least about 300 sccm oxygen to about 2000 sccm oxygen and a helium flow rate of about 400 to 1000 sccm helium.  
   
   
       12 . The semiconductor device of  claim 8  wherein the oxygen plasma is made by an exposure to oxygen gas to microwave energy.  
   
   
       13 . The semiconductor device of  claim 8  wherein the oxygen plasma is made by exposing oxygen gas to RF energy of about 150-900 watts.  
   
   
       14 . An in-process semiconductor comprising: 
 a layer of silicon-nitride, wherein the silicon-nitride is tempered by treating the layer of silicon-nitride with an oxygen plasma in a vacuum of about 3.0-6.5 Torr; and    a patterned layer of photo resist positioned on the layer of silicon-nitride, wherein a vertical edge of the patterned layer of photo resist is substantially free from footing and undercutting profile distortions, wherein the layer of photo resist is patterned using UV, electron beam or x-ray treatment.    
   
   
       15 . The semiconductor of  claim 14  wherein the tempered silicon-nitride film is substantially free from surface viscosity discontinuities.  
   
   
       16 . The semiconductor device of  claim 14  wherein the photo resist is an acid-catalyzed photo resist.  
   
   
       17 . The semiconductor device of  claim 14  wherein the silicon-nitride is tempered by treating the layer of silicon-nitride in the vacuum for a time of about 10 seconds to about 5 minutes, and in an atmosphere free of argon and comprising the oxygen plasma as the gas present in the greatest concentration, wherein the oxygen plasma flow rate is at least about 300 sccm oxygen.  
   
   
       18 . The semiconductor device of  claim 14  wherein the silicon-nitride is tempered by treating the layer of silicon-nitride in the vacuum for a time of about 10 seconds to about 5 minutes, and in an atmosphere consisting essentially of the oxygen plasma as the gas present in the greatest concentration, wherein the oxygen plasma is maintained at an oxygen flow rate of at least about 300 sccm oxygen to about 2000 sccm oxygen and a helium flow rate of about 400 to 1000 sccm helium.  
   
   
       19 . The semiconductor device of  claim 14  wherein the oxygen plasma is made by an exposure to oxygen gas to microwave energy.  
   
   
       20 . The semiconductor device of  claim 14  wherein the oxygen plasma is made by exposing oxygen gas to RF energy of about 150-900 watts.