Inverse resist coating process

Abstract

The invention provides systems and processes that form the inverse (photographic negative) of a patterned first coating. The patterned first coating is usually provided by a resist. After the first coating is patterned, a coating of a second material is provided thereover. The uppermost layer of the second coating is removed, where appropriate, to expose the patterned first coating. The patterned first coating is subsequently removed, leaving the second coating material in the form of a pattern that is the inverse pattern of the first coating pattern. The process may be repeated with a third coating material to reproduce the pattern of the first coating in a different material. Prior to applying the second coating, the patterned first coating may be trimmed by etching, thereby reducing the feature size and producing sublithographic features. In addition to providing sublithographic features, the invention gives a simple, efficient, and high fidelity method of obtaining inverse coating patterns.

What is claimed is:  
     
         1 . A method of processing a substrate, comprising the steps of: 
 forming a first coating comprising a resist material on a substrate surface;    irradiating and developing the first coating to form a patterned first coating on the substrate surface;    forming a second coating over the substrate surface;    removing the patterned first coating while leaving the second coating to form a pattern on the substrate that is approximately the negative of the pattern formed by the first coating prior to its removal; and    using the patterned second coating as a protective layer while subjecting the substrate to further processing.    
     
     
         2 . The method of  claim 1  further comprising the step of removing the patterned second coating.  
     
     
         3 . The method of  claim 1 , wherein the further processing comprises etching the substrate using the patterned second coating as a mask.  
     
     
         4 . The method of  claim 1 , wherein the further processing comprises forming a third coating on the substrate surface.  
     
     
         5 . The method of  claim 4  further comprising the step of removing the patterned second coating while leaving the third coating in a pattern similar to that of the first coating.  
     
     
         6 . The method of  claim 4  further processing comprises etching the substrate using the patterned third coating as a mask.  
     
     
         7 . The method of  claim 6  wherein the third coating has a substantially greater dry etch resistance than the first coating.  
     
     
         8 . The method of  claim 1  wherein the second coating has a substantially greater dry etch resistance than the first coating.  
     
     
         9 . The method of  claim 1 , wherein the second coating is composed primarily of organic material.  
     
     
         10 . The method of  claim 1 , wherein the second coating is formed by applying a liquid solution to the substrate followed by curing.  
     
     
         11 . The method of  claim 1  wherein, the second coating is spin coated on the substrate.  
     
     
         12 . The method of  claim 1 , wherein the first coating comprises a positive tone photoresist.  
     
     
         13 . The method of  claim 12 , wherein the first coating comprises a novolac.  
     
     
         14 . The method of  claim 1  wherein the patterned first coating is removed by irradiating with actinic radiation followed by developing.  
     
     
         15 . The method of  claim 1  further comprising etching the patterned first coating to reduce feature sizes prior to forming the second coating.  
     
     
         16 . The method of  claim 4  further comprising etching the patterned second coating to reduce feature sizes prior to forming the third coating.  
     
     
         17 . The method of  claim 16 , wherein after the patterned first coating is removed, the second coating material forms a pattern having gaps of less than about 0.5 μm.  
     
     
         18 . The method of  claim 17 , wherein, after the patterned first coating is removed, the second coating material forms a pattern having gaps of less than about 0.25 μm.  
     
     
         19 . A method of processing a semiconductor substrate comprising: 
 forming a patterned first coating;    forming a second coating with a pattern that is the negative of the first coating pattern; and    selectively etching the substrate surface where the second coating is absent.    
     
     
         20 . A method of forming sublithographic features in a substrate, comprising the steps of: 
 forming a patterned first coating on a substrate by coating the substrate with a resist, exposing the resist, and developing the resist;    etching the first coating to form a modified pattern that has features that are sublithographic for the resist and method of exposure used to form the patterned first coating;    forming a second coating over at least that portion of the substrate surface not covered by the patterned first coating;    removing the patterned first coating while leaving the second coating to form a pattern that is approximately the negative of the pattern formed by the first coating after etching; and    etching the substrate using the second coating as a mask.    
     
     
         21 . A system for forming an inverse resist coating on a semiconductor substrate, comprising: 
 a chamber for patterning a first coating comprising a resist material on a substrate surface;    a first dispenser for depositing a second coating over the substrate surface;    a second dispenser for depositing a developer for removing the patterned first coating while leaving the second coating to form a pattern on the substrate that is approximately the negative of the pattern formed by the first coating prior to its removal;    a measuring system for measuring at least one operating parameter within the chamber, wherein the operating parameter is required for patterning the first coating, depositing the second coating, or depositing the developer for removing the patterned first coating;    a processor operatively coupled to the measuring system and at least one of the first dispenser and the second dispenser, the processor receiving operating parameter data from the measuring system and the processor using the data to control at least one of the first dispenser and the second dispenser to form the inverse resist coating.    
     
     
         22 . The system of  claim 21 , wherein the measuring system comprises one of a scatterometry system, an ellipsometry system, an UV/vis spectrophotometry system, and an x-ray reflectometry system.  
     
     
         23 . The system of  claim 21 , wherein the processor comprises a memory.  
     
     
         24 . The system of  claim 21  further comprising a CMP apparatus for planarizing the second coating with the patterned first coating, the measuring system is operable for measuring CMP characteristics, the processor operatively coupled to the CMP apparatus, and the processor using data to control the CMP apparatus.  
     
     
         25 . The system of  claim 21 , wherein operating parameter is at least one of etch rate, thickness, surface pattern, deposition rate, and development rate.  
     
     
         26 . The system of  claim 21  further comprising a third dispenser for providing a trim etchant to trim etch the pattern of the second coating, the measuring system is operable for measuring the trim etch, the processor operatively coupled to the third dispenser, and the processor using data to control the trim etchant.