Integration of ALD tantalum nitride and alpha-phase tantalum for copper metallization application

Abstract

A method for forming a metal interconnect on a substrate is provided. In one aspect, the method comprises depositing a refractory metal containing barrier layer having a thickness that exhibits a crystalline like structure and is sufficient to inhibit atomic migration on at least a portion of a metal layer by alternately introducing one or more pulses of a metal-containing compound and one or more pulses of a nitrogen-containing compound; depositing a seed layer on at least a portion of the barrier layer; and depositing a second metal layer on at least a portion of the seed layer.

1 . A method for forming a metal interconnect on a substrate, comprising: 
 depositing a refractory metal containing barrier layer having a thickness that exhibits a crystalline like structure and is sufficient to inhibit atomic migration on at least a portion of a metal layer by alternately introducing one or more pulses of a metal-containing compound and one or more pulses of a nitrogen-containing compound;    depositing a seed layer on at least a portion of the barrier layer; and    depositing a second metal layer on at least a portion of the seed layer.    
     
     
         2 . The method of  claim 1 , wherein the refractory metal containing barrier comprises tantalum nitride.  
     
     
         3 . The method of  claim 1 , wherein a grain growth of the metal layer continues across the barrier layer into the second metal layer.  
     
     
         4 . The method of  claim 1 , wherein each pulse is repeated until the refractory metal containing barrier layer has a thickness less than about 20 angstroms.  
     
     
         6 . The method of  claim 1 , wherein the refractory metal containing barrier layer has a thickness of about 10 angstroms.  
     
     
         7 . The method of  claim 1 , wherein the alternate pulsing is repeated between about 10 and about 70 times to form the refractory metal nitride layer.  
     
     
         8 . The method of  claim 1 , further comprising flowing a purge gas continuously during each pulse of the metal-containing compound and each pulse of the nitrogen-containing compound.  
     
     
         9 . The method of  claim 8 , wherein the purge gas comprises argon, nitrogen, helium, or combinations thereof.  
     
     
         10 . The method of  claim 1 , wherein each pulse of the metal-containing compound and the nitrogen-containing is separated by a time delay.  
     
     
         11 . The method of  claim 10 , wherein each time delay is long enough for a volume of the metal-containing compound or a volume of the nitrogen-containing compound to adsorb onto the substrate surface.  
     
     
         12 . The method of  claim 11 , wherein the time delay is long enough to remove non-adsorbed molecules from the substrate surface.  
     
     
         13 . The method of  claim 1 , wherein the nitrogen-containing compound is selected from a group consisting of ammonia; hydrazine; methylhydrazine; dimethylhydrazine; t-butylhydrazine; phenylhydrazine; azoisobutane; ethylazide; derivatives thereof; and combinations thereof.  
     
     
         14 . The method of  claim 1 , wherein the metal-containing compound is selected from a group consisting of: tetrakis (dimethylamino) titanium (TDMAT); tetrakis (ethylmethylamino) titanium (TEMAT); tetrakis (diethylamino) titanium (TDEAT); titanium tetrachloride (TiCl 4 ); titanium iodide (TiI 4 ); titanium bromide (TiBr 4 ); t-butylimino tris(diethylamino) tantalum (TBTDET); pentakis (ethylmethylamino); tantalum (PEMAT); pentakis (dimethylamino) tantalum (PDMAT); pentakis (diethylamino) tantalum (PDEAT); t-butylimino tris(diethyl methylamino) tantalum(TBTMET); t-butylimino tris(dimethyl amino) tantalum (TBTDMT); bis(cyclopentadienyl) tantalum trihydride ((Cp) 2 TaH 3 ); bis(methylcyclopentadienyl) tantalum trihydride ((CpMe) 2 TaH 3 ); derivatives thereof; and combinations thereof.  
     
     
         15 . The method of  claim 1 , wherein the first and second metal layers each comprise tungsten, copper, or a combination thereof.  
     
     
         16 . The method of  claim 1 , wherein the seed layer comprises a first seed layer deposited over the barrier layer and a second seed layer deposited over the first seed layer.  
     
     
         17 . The method of  claim 16 , wherein the first seed layer comprises a copper alloy seed layer of the copper and a metal selected from the group consisting of aluminum, magnesium, titanium, zirconium, tin, and combinations thereof or wherein the first seed layer comprises a metal selected from the group consisting of aluminum, magnesium, titanium, zirconium, tin, and combinations thereof.  
     
     
         18 . A method for forming a metal interconnect on a substrate, comprising: 
 depositing a first metal layer on a substrate surface;    depositing a titanium silicon nitride layer having a thickness less than about 20 angstroms over at least a portion of the first metal layer by alternately introducing one or more pulses of a titanium-containing compound, one or more pulses of a silicon-containing compound, and one or more pulses of a nitrogen-containing compound;    depositing a dual alloy seed layer; and    depositing a second metal layer on at least a portion of the dual alloy seed layer.    
     
     
         19 . A method for forming a metal interconnect on a substrate, comprising: 
 depositing a bilayer barrier having a thickness less than about 20 angstroms on at least a portion of a metal layer, the bilayer barrier comprising: 
 a first layer of tantalum nitride deposited by alternately introducing one or more pulses of a tantalum-containing compound and one or more pulses of a nitrogen-containing compound; and  
 a second layer of alpha phase tantalum;  
   depositing a dual alloy seed layer; and    depositing a second metal layer on at least a portion of the dual alloy seed layer.    
     
     
         20 . A method for forming a metal interconnect on a substrate, comprising: 
 depositing a first metal layer on a substrate surface;    depositing a tantalum nitride barrier layer having a thickness less than about 20 angstroms on at least a portion of the first metal layer by alternately introducing one or more pulses of a tantalum-containing compound and one or more pulses of a nitrogen-containing compound;    depositing a dual alloy seed layer comprising copper and a metal selected from the group consisting of aluminum, magnesium, titanium, zirconium, tin, and combinations thereof; and    depositing a second metal layer on at least a portion of the dual alloy seed layer.