Insert target assembly and method of making same

Abstract

Method of forming a two-piece hollow cathode sputter target assembly and the assembly formed thereby. The sputter target assembly includes an outer shell having a substantially cylindrical side wall and is composed of a relatively low purity metallic material. A sputtering insert includes a substantially cylindrical side wall and is concentrically received within, and bonded to, the outer shell. The sputtering insert is composed of a relatively high purity metallic material as used for depositing a thin layer or film onto a desired substrate.

1 . A sputter target assembly comprising: 
 a sputtering insert including a side wall connected to an end wall, said side and end walls having inner and outer surfaces;    an outer shell including a side wall connected to an end wall, said side and end walls having inner and outer surfaces; and    wherein said sputtering insert is received within said outer shell and said inner surfaces of said outer shell are bonded to said outer surfaces of said sputtering insert thereby forming a substantially hollow sputter target assembly.    
     
     
         2 . The sputter target assembly of claim I wherein said sputtering insert is composed of a first metallic material selected from the group consisting of titanium, copper, tantalum, cobalt, tungsten, aluminum and alloys thereof.  
     
     
         3 . The sputter target assembly of claim I wherein said outer shell is composed of a second metallic material selected from the group consisting of aluminum, copper, steel, titanium and alloys thereof.  
     
     
         4 . The sputter target assembly of  claim 1  wherein said outer shell and said sputtering insert are diffusion bonded together by hot isostatically pressing said outer shell together with said sputtering insert at a temperature and at a pressure for a period of time.  
     
     
         5 . The sputter target assembly of claim I wherein said outer shell and said sputtering insert are bonded together by an interference fit between said outer and inner side walls, said interference fit formed at room temperature.  
     
     
         6 . A sputter target assembly comprising: 
 a sputtering insert composed of a first metallic material, said sputtering insert including a side wall defining a longitudinal axis and connected to an end wall, said side and end walls having inner and outer surfaces, said inner surfaces defining a sputtering surface; and    an outer shell composed of a second metallic material, said outer shell including a side wall connected to an end wall, said side and end walls having inner and outer surfaces, said inner surfaces of said outer shell adapted to mate with said outer surfaces of said sputtering insert along an area therebetween to form a substantially hollow sputter target assembly, said area having a portion extending coaxial to said longitudinal axis.    
     
     
         7 . The sputter target assembly of  claim 6  wherein said first metallic material is selected from the group consisting of titanium, copper, tantalum, cobalt, tungsten, aluminum and alloys thereof.  
     
     
         8 . The sputter target assembly of  claim 6  wherein said second metallic material is selected from the group consisting of aluminum, copper, steel, titanium and alloys thereof.  
     
     
         9 . The sputter target assembly of  claim 6  wherein said outer shell and said sputtering insert are diffusion bonded together by hot isostatically pressing said outer shell together with said sputtering insert at a temperature and at a pressure for a period of time.  
     
     
         10 . The sputtering target assembly of  claim 6  wherein said sputtering insert is received within said outer shell.  
     
     
         11 . A method of forming a sputter target assembly used for forming a film on a substrate, said method comprising the steps of: 
 forming a blank of first metallic material into a sputtering insert including a side wall connected to an end wall, said side and end walls having outer mating and inner sputtering surfaces;    forming a blank of second metallic material into an outer shell including a side wall connected to an end wall, said side and end walls having inner mating surfaces;    placing said sputtering insert within said outer shell; and    bonding said inner mating surfaces of said outer shell to said outer mating surfaces of said sputtering insert thereby forming a substantially hollow sputter target assembly.    
     
     
         12 . The method as recited in  claim 11  wherein said step of bonding includes pressing said outer shell and said sputtering insert together along said inner and outer mating surfaces at a temperature below the melting points of said first and second metallic materials such that a diffusion bond is formed along said inner and outer mating surfaces.  
     
     
         13 . The method as recited in  claim 11  wherein said step of bonding includes: 
 providing said sputtering insert at a first temperature;  
 heating said outer shell to a second temperature prior to said step of placing said sputtering insert within said outer shell; and  
 returning said sputtering insert and said outer shell to room temperature after said step of placing said sputtering insert within said outer shell, thereby providing an interference fit between said side walls of said sputtering insert and said outer shell at room temperature.  
 
     
     
         14 . A method of forming a sputter target assembly comprising: 
 providing a sputtering insert including a side wall and an end wall, said side wall having an outer mating surface and an inner sputtering surface, said sputtering insert composed of a first metallic material;    providing an outer shell including a side wall having an inner mating surface, said outer shell composed of a second metallic material;    placing said sputtering insert within said outer shell; and    pressing said outer shell and said sputtering insert together along said inner and outer mating surfaces at a temperature below melting points of said first and second metallic materials such that a diffusion bond is formed along said inner and outer mating surfaces.    
     
     
         15 . The method as recited in  claim 14  wherein said step of pressing includes the steps of: 
 placing a plug within said sputtering insert;  
 placing said sputtering insert and plug within a hot isostatic press can;  
 securing a closure plate to said can to form a vacuum tight can assembly;  
 evacuating residual air from said can assembly; and  
 subjecting said can assembly to a temperature and a pressure for a period of time.  
 
     
     
         16 . The method as recited in  claim 15  wherein said temperature is about 565° C., said pressure is about 10.17 MPa and said time is about 3 hours.  
     
     
         17 . The method as recited in  claim 14  wherein said first metallic material is selected from the group consisting of titanium, copper, tantalum, cobalt, tungsten, aluminum and alloys thereof.  
     
     
         18 . The method as recited in  claim 14  wherein said second metallic material is selected from the group consisting of aluminum, copper, steel, titanium and alloys thereof.  
     
     
         19 . The method as recited in  claim 15  wherein said plug is composed of a material selected from the group consisting of aluminum, steel, graphite and alloys thereof.  
     
     
         20 . The method as recited in  claim 15  wherein said outer shell forms said hot isostatic press can.  
     
     
         21 . A method of forming a sputtering target assembly comprising the steps of: 
 providing a substantially planar sputtering blank composed of a first metallic material having a first mating surface;    providing a substantially planar shell blank composed of a second metallic material having a second mating surface;    bonding said shell blank to said sputtering blank thereby forming a blank assembly; and    forming said blank assembly into a cup-shaped sputter target assembly including an outer shell composed of said shell blank and a sputtering insert composed of said sputtering blank;    wherein said sputtering insert is concentrically disposed within said outer shell such that said sputtering target assembly includes an outer substantially cylindrical wall defined by said outer shell and an inner substantially cylindrical wall defined by said sputtering insert, said inner wall bonded to said outer wall.    
     
     
         22 . The method as recited in  claim 21  wherein said step of bonding comprises pressing said first mating surface together with said second mating surface at a temperature below melting points of said first and second metallic materials such that a diffusion bond is formed along said first and second mating surfaces.  
     
     
         23 . The method as recited in  claim 21  wherein said step of bonding comprises forming a vacuum between said first and second mating surfaces and welding said shell blank to said sputtering blank.  
     
     
         24 . A method of forming a sputtering target assembly comprising the steps of: 
 providing a sputtering blank composed of a first metallic material having a first mating surface;    providing a shell blank composed of a second metallic material having a second mating surface;    forming a vacuum between said first and second mating surfaces and weld bonding said shell blank to said sputtering blank thereby forming a blank assembly; and    forming said blank assembly into a hollow sputter target assembly including an outer shell composed of said shell blank and a sputtering insert composed of said sputtering blank;    wherein said sputtering insert is disposed within said outer shell such that said sputtering target assembly includes an outer wall defined by said outer shell and an inner wall defined by said sputtering insert, said inner wall bonded to said outer wall.    
     
     
         25 . The method as recited in  claim 24  wherein said sputtering and shell blanks are substantially planar.  
     
     
         26 . The method as recited in  claim 24  wherein said sputtering insert is concentrically disposed within said outer shell and said inner and outer walls are substantially cylindrical.