Maintenance of photoresist adhesion and activity on the surface of dielectric ARCS for 90 nm feature sizes

Abstract

We have traced the detachment of photoresist during development of patterned features in the range of about 90 nm and smaller to a combination of the reduced “foot print” of the pattern on the underlying substrate and to the contact angle between the underlying substrate surface and the developing reagent. By maintaining a contact angle of about 30 degrees or greater, the detachment of the photoresist from the underlying substrate can be avoided for photoresists including feature sizes in the range of about 90 nm. We have achieved an increased contact angle between the DARC surface and a water-based CAR photoresist developer while simultaneously reducing CAR poisoning by treating the surface of the DARC after film formation.

1 . A method of reducing the risk of detachment of photoresist from an underlying substrate during development of a photoresist pattern using a fluid developer, comprising: controlling the surface composition of said underlying substrate so that a contact angle formed between said underlying substrate with a developer used to develop said photoresist pattern is about 20 degrees or greater.  
     
     
         2 . A method in accordance with  claim 1 , wherein said photoresist pattern contains features which are less than about 120 nm in size.  
     
     
         3 . A method in accordance with  claim 2 , wherein said photoresist pattern contains features which are less than about 90 nm in size.  
     
     
         4 . A method in accordance with  claim 3 , wherein said contact angle formed between said underlying substrate with a developer used to develop said photoresist pattern is about 30 degrees or greater.  
     
     
         5 . A method in accordance with  claim 1 , wherein controlling of said surface composition of said underlying substrate is accomplished by controlling the composition of a depositing film which forms the surface of said underlying substrate.  
     
     
         6 . A method in accordance with  claim 5 , wherein said depositing film is deposited using plasma enhanced CVD.  
     
     
         7 . A method in accordance with  claim 6 , wherein said depositing film is a DARC.  
     
     
         8 . A method in accordance with  claim 7 , wherein an amount of a Group IV element present in said DARC is controlled, whereby said contact angel is controlled.  
     
     
         9 . A method in accordance with  claim 8 , wherein said Group IV element is carbon.  
     
     
         10 . A method in accordance with  claim 8 , wherein said Group IV element is silicon.  
     
     
         11 . A method in accordance with  claim 8 , wherein said Group IV element is germanium.  
     
     
         12 . A method in accordance with  claim 8 , wherein said DARC is an inorganic DARC.  
     
     
         13 . A method in accordance with  claim 5  or  claim 6 , or  claim 7 , or  claim 8 , wherein said film deposition employs a power input which includes the use of a plurality of frequencies.  
     
     
         14 . A method in accordance with  claim 13 , wherein said power input includes use of a plurality of RF power inputs.  
     
     
         15 . A method in accordance with  claim 13 , wherein said power input includes the use of both microwave and RF power inputs.  
     
     
         16 . A method in accordance with  claim 1 , wherein controlling of said surface composition of said underlying substrate is accomplished by treating said surface with a plasma.  
     
     
         17 . A method in accordance with  claim 16 , wherein said surface being treated is a DARC.  
     
     
         18 . A method in accordance with  claim 17 , wherein said plasma is a hydrogen-comprising plasma which makes hydrogen species available to react with said DARC surface.  
     
     
         19 . A method in accordance with  claim 18 , wherein said plasma is a hydrogen plasma.  
     
     
         20 . A method in accordance with  claim 17 , wherein said plasma is a helium-comprising plasma.  
     
     
         21 . A method in accordance with  claim 20 , wherein said plasma is a helium plasma.  
     
     
         22 . A method in accordance with  claim 1 , wherein controlling of said surface composition of said underlying substrate is accomplished by controlling the composition of a capping layer deposited over a DARC.  
     
     
         23 . A method in accordance with  claim 22 , wherein said depositing film is deposited using plasma enhanced CVD.  
     
     
         24 . A method in accordance with  claim 22  or  claim 23 , wherein said capping layer is silicon-containing.  
     
     
         25 . A method in accordance with  claim 22  or  claim 23 , wherein said capping layer is essentially α-carbon.  
     
     
         26 . A method in accordance with  claim 24 , wherein said silicon-containing capping layer is α-silicon.  
     
     
         27 . A method in accordance with  claim 1 , or  claim 2 , or  claim 8 , or  claim 16 , or  claim 22 , wherein said developer is a water-based developer.  
     
     
         28 . A method in accordance with  claim 27 , wherein said developer has the property of being basic.  
     
     
         29 . A method in accordance with  claim 1  or  claim 2 , or  claim 8 , or  claim 16 , or  claim 22 , wherein said contact angle ranges from about 35 degrees to about 90 degrees.  
     
     
         30 . A method of reducing photoresist poisoning when the photoresist is a chemically amplified positive photoresist which produces an acid in pattern areas of the photoresist which are to be removed upon development, comprising: 
 controlling the surface composition of a substrate underlying said photoresist by plasma treatment of said surface.    
     
     
         31 . A method in accordance with  claim 30 , wherein said plasma treatment employs a plasma generation power input including more than one frequency.  
     
     
         32 . A method in accordance with  claim 30  or  claim 31 , wherein said substrate underlying said photoresist is a DARC.  
     
     
         33 . A method in accordance with  claim 32 , wherein said DARC is an inorganic DARC.  
     
     
         34 . A method in accordance with  claim 33 , wherein said DARC is a silicon-containing DARC, and wherein said plasma used for treatment is a hydrogen-containing plasma.  
     
     
         35 . A method in accordance with  claim 32 , wherein said DARC is an organic DARC, and wherein said plasma used for treatment is a hydrogen-containing plasma.  
     
     
         36 . A method in accordance with  claim 32 , wherein said plasma used for treatment is a helium-containing plasma.  
     
     
         37 . A method in accordance with  claim 33 , wherein said DARC is a silicon-containing DARC, and wherein said plasma used for treatment is a helium-containing plasma.  
     
     
         38 . A method in accordance with  claim 32 , wherein said DARC is an organic DARC, and wherein said plasma used for treatment is a helium-containing plasma.  
     
     
         39 . A method of reducing photoresist poisoning when the photoresist is a chemically amplified positive photoresist which produces an acid in pattern areas of the photoresist which are to be removed upon development, comprising: 
 controlling the surface composition of a substrate underlying said photoresist by PECVD deposition of a capping film of α-silicon over an underlying inorganic nitrogen-free DARC.    
     
     
         40 . A method of reducing photoresist poisoning when the photoresist is a chemically amplified positive photoresist which produces an acid in pattern areas of the photoresist which are to be removed upon development, comprising: 
 controlling the surface composition of a substrate underlying said photoresist by PECVD deposition of a capping film of α-carbon over an underlying inorganic nitrogen-free DARC.