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. The method includes depositing a refractory metal-containing barrier layer having a thickness less than about 20 angstroms 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. The method also includes 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. The barrier layer provides adequate barrier properties and allows the grain growth of the metal layer to continue across the barrier layer into the second metal layer thereby enhancing the electrical performance of the interconnect.

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.  
     
     
         5 . The method of  claim 1 , wherein each pulse is repeated until the refractory metal containing barrier layer has a thickness of about 10 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 8 , wherein the purge gas has a flowrate of about 200 sccm to about 1,000 sccm.  
     
     
         11 . The method of  claim 1 , wherein each pulse of the metal-containing compound has a flow rate of about 100 sccm to about 400 sccm.  
     
     
         12 . The method of  claim 1 , wherein each pulse of the nitrogen-containing compound has a flow rate of about 200 sccm to about 600 sccm.  
     
     
         13 . The method of  claim 1 , wherein each pulse of the metal-containing compound and the nitrogen-containing is separated by a time delay.  
     
     
         14 . The method of  claim 13 , 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.  
     
     
         15  The method of  claim 14 , wherein the time delay is long enough to remove non-adsorbed molecules from the substrate surface.  
     
     
         16 . 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.  
     
     
         17 . 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 (Til 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.  
     
     
         18 . The method of  claim 1 , wherein the first and second metal layers each comprise tungsten, copper, or a combination thereof.  
     
     
         19 . The method of  claim 1 , wherein the seed layer comprises copper and a metal selected from the group consisting of aluminum, magnesium, titanium, zirconium, tin, and combinations thereof.  
     
     
         20 . The method of  claim 1 , wherein the seed layer is a dual alloy seed layer comprising copper and aluminum.  
     
     
         21 . 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.  
     
     
         22 . The method of  claim 21 , 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.  
     
     
         23 . The method of  claim 21 , wherein the second seed layer comprises undoped copper.  
     
     
         24 . The method of  claim 21 , wherein the first seed layer comprises a metal selected from the group consisting of aluminum, magnesium, titanium, zirconium, tin, and combinations thereof.  
     
     
         25 . The method of  claim 24 , wherein the second seed layer comprises undoped copper.  
     
     
         26 . A method for forming a metal interconnect on a substrate, comprising: 
 depositing a tantalum nitride barrier layer having a thickness less than about 20 angstroms on at least a portion of a 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; and    depositing a second metal layer on at least a portion of the dual alloy seed layer.    
     
     
         27 . 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.    
     
     
         28 . A method for forming a metal interconnect on a substrate, comprising: 
 depositing a tantalum silicon nitride layer having a thickness less than about 20 angstroms on at least a portion of a metal layer by alternately introducing one or more pulses of a tantalum-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.    
     
     
         29 . 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.    
     
     
         30 . 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.    
     
     
         31 . The method of  claim 30 , wherein the dual alloy seed layer comprises a first seed layer deposited over the barrier layer and a second seed layer deposited over the first seed layer.  
     
     
         32 . The method of  claim 31 , wherein the first seed layer comprises a copper alloy seed layer of the copper and the metal.  
     
     
         33 . The method of  claim 31 , wherein the second seed layer comprises undoped copper.