Crosslinkable fill compositions for uniformly protecting via and contact holes

Abstract

A via and contact hole fill composition and method for using the composition in the dual damascene production of circuits is provided. Broadly, the fill compositions include a quantity of solid components including a polymer binder and a solvent system for the solid components. The boiling point of the solvent system is less than the cross-linking temperature of the composition. Preferred solvents for use in the solvent system include those selected from the group consisting of alcohols, ethers, glycol ethers, amides, ketones, and mixtures thereof. Preferred polymer binders are those having an aliphatic backbone and a molecular weight of less than about 80,000, with polyesters being particularly preferred. In use, the fill composition is applied to the substrate surfaces forming the contact or via holes as well as to the substrate surfaces surrounding the holes, followed by heating to the composition reflow temperature so as to cause the composition to uniformly flow into and cover the hole-forming surfaces and substrate surfaces. The composition is then cured, and the remainder of the dual damascene process is carried out.

We claim:  
     
         1 . In a fill composition for coating contact or via holes formed in a base material to protect the base material during etching processes, the composition including a quantity of solid components including a polymer binder, and a solvent system for said solid components, the improvement which comprises: 
 said composition being at least about 70% removed from the base material when subjected to a pre-bake thermal stability test; and    said composition having less than about 15% shrinkage when subjected to a film shrinkage test.    
     
     
         2 . The composition of  claim 1 , said solvent system boiling point being less than about 160° C.  
     
     
         3 . The composition of  claim 1 , said solvent system having a flash point of greater than about 85° C.  
     
     
         4 . The composition of  claim 1 , wherein said polymer binder has a molecular weight of less than about 80,000.  
     
     
         5 . The composition of  claim 1 , wherein said polymer binder comprises polyacrylate.  
     
     
         6 . The composition of  claim 1 , wherein said solvent system includes a solvent selected from the group consisting of alcohols, ethers, glycol ethers, amides, esters, ketones, and mixtures thereof.  
     
     
         7 . The composition of  claim 6 , wherein said solvent is PGME.  
     
     
         8 . The composition of  claim 1 , wherein said composition includes a cross-linking agent.  
     
     
         9 . The composition of  claim 8 , wherein said cross-linking agent is selected from the group consisting of aminoplasts, epoxides, isocyanates, acrylics, and mixtures thereof.  
     
     
         10 . The composition of  claim 1 , wherein said polymer binder includes a cross-linking moiety.  
     
     
         11 . The composition of  claim 8 , wherein the cross-linking temperature of said composition is from about 150-220° C.  
     
     
         12 . The composition of  claim 1 , wherein said solid components, when mixed together, have a melting point of less than about 200° C.  
     
     
         13 . The composition of  claim 1 , said composition and said base material each having respective etch rates, said composition etch rate being approximately equal to said base material etch rate.  
     
     
         14 . The composition of  claim 1 , said composition further including a light-absorbing dye.  
     
     
         15 . The composition of  claim 14 , wherein said dye is bonded to said polymer binder.  
     
     
         16 . The composition of  claim 1 , said composition further including a wetting agent.  
     
     
         17 . The composition of  claim 16 , wherein said wetting agent is a fluorinated surfactant.