Copper film containing tungsten carbide for improving electrical conductivity, thermal stability and hardness properties and a manufacturing method for the copper film

Abstract

A copper film containing tungsten carbide is adapted to be formed on a substrate and contains a copper layer having tungsten carbide in atomic ratios of 0.4 to 12.2% in tungsten and of 0.7 to 7.4% in carbon. To achieve the copper film, a manufacturing method has the acts of: adjusting a non-overlapping area between a copper target and a tungsten carbide target; co-sputtering the copper target and the tungsten carbide target to form the copper film containing tungsten carbide; and optionally annealing the copper film containing tungsten carbide to change the microstructure of the copper film. By sputtering the tungsten carbide with copper, the achieved copper film has excellent electrical conductivity, thermal stability at high temperatures and hardness properties.

1 . A copper film containing tungsten carbide for improving electrical conductivity, thermal stability and hardness properties, the copper film comprising: 
 a copper layer in a form of a supersaturated solid solution; and    tungsten carbide present inside the copper layer in nano-crystallite.    
     
     
         2 . The copper film as claimed in  claim 1 , wherein tungsten carbide is represented as atomic ratios of 0.4 to 12.2% in tungsten and of 0.7 to 7.4% in carbon, the atomic rations are on a basis of total atoms in the copper film.  
     
     
         3 . A manufacturing method for forming a copper film containing tungsten carbide as claimed in  claim 1 , wherein the manufacturing method comprising acts of: 
 adjusting a non-overlapping area between a copper target and a tungsten carbide target; and    co-sputtering the copper target and the tungsten carbide target to form the copper film containing tungsten carbide, wherein sputtering power is 100W and sputtering pressure is 1×10 −2  to 10×10 −3  torr;    by adjusting the non-overlapping area of the tungsten carbide target, ratios of tungsten carbide in the copper film are regularized.    
     
     
         4 . The method as claimed in  claim 3 , wherein the sputtering temperature in the sputtering act has a range from 25° C. to 100° C.  
     
     
         5 . The method as claimed in  claim 3 , wherein ratios of the non-overlapping area of the tungsten carbide target to the copper target are selectively preferable 4.0%, 21.3%, 29.3% and 49.9 to obtain the copper film containing tungsten carbide in different ratios.  
     
     
         6 . The method as claimed in  claim 3 , wherein the method further comprising an annealing act after the sputtering act and the annealing acts is of: 
 annealing the copper film containing tungsten carbide at an annealing pressure of 1×10 −6  to 1×10 −7  torr, a heating speed of 4 to 6° C. per min, at an annealing temperature ranging from 200 to 650° C. for one hour duration.    
     
     
         7 . The method as claimed in  claim 2 , wherein an ultra-microhardness of the copper film containing tungsten carbide increases with increment of the tungsten carbide and maximally is 4 times greater than an ultra-microhardness of a pure copper film.  
     
     
         8 . The method as claimed in  claim 6 , wherein an ultra-microhardness of the copper film containing tungsten carbide after annealing is 3 times greater than an ultra-microhardness of a pure copper film.  
     
     
         9 . The method as claimed in  claim 4 , wherein an ultra-microhardness of the copper film containing tungsten carbide after annealing at 650° C. for one-hour duration is 4 times greater than an ultra-microhardness of a pure copper film.