MoC掺杂钌基合金无籽晶阻挡层微结构及热稳定性研究
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摘要
采用磁控共溅射Ru和MoC靶制备非晶RuMoC薄膜。用四探针仪(FPPT)、X射线光电子能谱仪(XPS)、高分辨率透射电镜(HRTEM)和小角掠射X射线衍射仪(GIXRD)表征不同掺杂组分RuMoC薄膜和不同温度退火态Cu/RuMoC/p-SiOC∶H/Si多层膜系的方块电阻、成分和微观结构。结果表明,通过调控Ru膜中掺入Mo和C元素的含量能够实现RuMoC合金薄膜微结构设计及抑制膜体残余氧含量,且当MoC和Ru靶的溅射功率比为0.5时获得的RuMoCII薄膜综合性能最佳;500℃退火态RuMoC II薄膜中C-Mo和C-Ru化学键均未出现大量断裂,两者协同作用抑制了RuMoC薄膜再结晶和膜体氧含量升高,是Cu/RuMoCII/p-SiOC∶H/Si多层膜系具有高温热稳定性和优异电学性能的主要机制。
Cu has been adopted to replace Al for conduction lines and contact structures in very large-scale integrated circuits due to its low resistivity. However,Cu could rapidly react with the SiO_2-based dielectric under 300 ℃ and form deep level impurities which are strong sink for carriers,leading to the dielectric degradation of the devices. Therefore,it is important to insert a stable barrier between the Cu wiring and SiO_2-based dielectric for suppressing Cu diffusion and improving the adhesive strength.The prediction of international technology roadmap for semiconductors that the thickness of diffusion barrier would be further reduced to 3 nm for 22 nm technology node indicates the widely being used Ta/TaN barrier would be incompetent in the future,since Ta/TaN barrier at the limited thickness exhibits a high resistivity and a columnar grain structure which provides lots of vertical grain boundaries for Cu diffusion.Therefore a directly platable amorphous single barrier with low resistivity is highly desired. In this work,MoC are chosen as impurity to expect for amorphous Ru-based films. The RuMoC films with different components were deposited by RF magnetron co-sputtering with different deposition power ratios of MoC versus Ru targets. The sheet resistances,microstructures and components of the RuMoC films in RuMoC/Si and Cu/RuMoC/p-SiOC∶H/Si structures were studied. The sheet resistances,residual oxygen contents and microstructures of the RuMoC films have close correlation with the doping contents of Mo and C elements which can be easily controlled by tuning the deposition power on MoC target. When the deposition power ratio of MoC versus Ru targets was 0.5,amorphous RuMoCII film with low sheet resistance and residual oxygen content was obtained. After annealing at 500 ℃ the Mo-C and Ru-C bonds were well-preserved and co-suppressed the recrystallization of the film and the increasing of the oxygen content,contributing to excellent thermal stability and electrical properties of Cu/RuMoCII/p-SiOC∶H/Si film.
Cu has been adopted to replace Al for conduction lines and contact structures in very large-scale integrated circuits due to its low resistivity. However,Cu could rapidly react with the SiO_2-based dielectric under 300 ℃ and form deep level impurities which are strong sink for carriers,leading to the dielectric degradation of the devices. Therefore,it is important to insert a stable barrier between the Cu wiring and SiO_2-based dielectric for suppressing Cu diffusion and improving the adhesive strength.The prediction of international technology roadmap for semiconductors that the thickness of diffusion barrier would be further reduced to 3 nm for 22 nm technology node indicates the widely being used Ta/TaN barrier would be incompetent in the future,since Ta/TaN barrier at the limited thickness exhibits a high resistivity and a columnar grain structure which provides lots of vertical grain boundaries for Cu diffusion.Therefore a directly platable amorphous single barrier with low resistivity is highly desired. In this work,MoC are chosen as impurity to expect for amorphous Ru-based films. The RuMoC films with different components were deposited by RF magnetron co-sputtering with different deposition power ratios of MoC versus Ru targets. The sheet resistances,microstructures and components of the RuMoC films in RuMoC/Si and Cu/RuMoC/p-SiOC∶H/Si structures were studied. The sheet resistances,residual oxygen contents and microstructures of the RuMoC films have close correlation with the doping contents of Mo and C elements which can be easily controlled by tuning the deposition power on MoC target. When the deposition power ratio of MoC versus Ru targets was 0.5,amorphous RuMoCII film with low sheet resistance and residual oxygen content was obtained. After annealing at 500 ℃ the Mo-C and Ru-C bonds were well-preserved and co-suppressed the recrystallization of the film and the increasing of the oxygen content,contributing to excellent thermal stability and electrical properties of Cu/RuMoCII/p-SiOC∶H/Si film.
引文
[1]Liu B,Song Z X,Li Y H,et al.An ultrathin Zr(Ge)alloy film as an exhaustion interlayer combined with Cu(Zr)seed layer for the Cu/porous Si OC∶H dielectric integration[J].Appl.Phys.Lett.,2008,93:174108
[2]Rosenberg R,Edelstein D C,Hu C K,et al.Copper metallization for high performance silicon technology[J].Annu.Rev.Mater.Sci.,2000,30:229
[3]Semiconductor Industry Association.2005 International Technology Roadmap for Semiconductors[Z].TX,USA:International SEMATECH,2005:1
[4]Chang C A.Formation of copper silicides from Cu(100)/Si(100)and Cu(111)/Si(111)structures[J].J.Appl.Phys.,1990,67:566
[5]Leu L C,Norton D P,Mc Elwee-White L,et al.Ir/Ta N as a bilayer diffusion barrier for advanced Cu interconnects[J].J.Appl.Phys.Lett.,2008,92:111917
[6]Wang J H,Chen L J,Lu Z C,et al.Ta and Ta-N diffusion barriers sputtered with various N2/Ar ratios for Cu metallization[J].J.Vac.Sci.Technol.,2002,20B:1522
[7]Yang L Y,Zhang D H,Li C Y,et al.Comparative study of Ta,Ta N and Ta/Ta N bi-layer barriers for Cu-ultra low-k porous polymer integration[J].Thin Solid Films,2004,462-463:176
[8]Hsu K C,Perng D C,Wang Y C.Robust ultra-thin Ru Mo alloy film as a seedless Cu diffusion barrier[J].J.Alloys.Compd.,2012,516:102
[9]Arunagiri T N,Zhang Y,Chyan O,et al.5 nm ruthenium thin film as a directly plateable copper diffusion barrier[J].Appl.Phys.Lett.,2005,86:083104
[10]Liu B,Zhang Y P,Xu K W.Improvement of thermal stability and electrical property of Cu/Cu(Zr)/Si OC∶H film stack by controlling the structure and composition of Zr(Ge)nano-interlayer[J].Microelectron.Eng.,2014,118:41
[11]Bouhtiyya S,Lucio Porto R,La?k B,et al.Application of sputtered ruthenium nitride thin films as electrode material for energystorage devices[J].Scr.Mater.,2013,68:659
[12]Damayanti M,Sritharan T,Mhaisalkar S G,et al.Effects of dissolved nitrogen in improving barrier properties of ruthenium[J].Appl.Phys.Lett.,2006,88:044101
[13]Jiao G H,Liu B,Li Q R.Investigation of amorphous Ru Mo C alloy films as a seedless diffusion barrier for Cu/p-Si OC∶H ultralowk dielectric integration[J].Appl.Phys.,2015,120A:579
[14]Henderson L B,Ekerdt J G.Time-to-failure analysis of 5 nm amorphous Ru(P)as a copper diffusion barrier[J].Thin Solid Films,2009,517:1645
[15]Hsu K C,Perng D C,Yeh J B,et al.Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects[J].Appl.Surf.Sci.,2012,258:7225
[16]Wojcik H,Krien C,Merkel U,et al.Characterization of Ru-Mn composites for ULSI interconnects[J].Microelectron.Eng.,2013,112:103
[17]Cattaruzza E,Battaglin G,Riello P,et al.On the synthesis of a compound with positive enthalpy of formation:Zinc-blende-like Ru N thin films obtained by rf-magnetron sputtering[J].Appl.Surf.Sci.,2014,320:863
[18]Jansson U,Lewin E.Sputter deposition of transition-metal carbide films-a critical review from a chemical perspective[J].Thin Solid Films,2013,536:1
[19]Trgala M,?emli?ka M,Neilinger P,et al.Superconducting Mo C thin films with enhanced sheet resistance[J].Appl.Surf.Sci.,2014,312:216
[20]Huang Q F,Yoon S F,Rusli,et al.Molybdenum-containing carbon films deposited using the screen grid technique in an electron cyclotron resonance chemical vapor deposition system[J].Diam.Relat.Mater.,2000,9:534
[21]Kacim S,Binst L,Reniers F,et al.Composition and structure of reactively sputter-deposited molybdenum-carbon films[J].Thin Solid Films,1996,287:25
[22]Liu B,Yang J J,Liu C H,et al.Ultrathin Cu Si N/p-Si C∶H bilayer capping barrier for Cu/ultralow-k dielectric integration[J].Appl.Phys.Lett.,2009,94:153116
[23]Laurila T,Zeng K,Kivilahti J K,et al.Chemical stability of Ta diffusion barrier between Cu and Si[J].Thin Solid Films,2000,373:64
[24]Holloway K,Fryer P M,Cabral C Jr,et al.Tantalum as a diffusion barrier between copper and silicon:failure mechanism and effect of nitrogen additions[J].J.Appl.Phys.,1992,71:5433
[25]Seibt M,Hedemann H,Riedel A A,et al.Structural and electrical properties of metal silicide precipitates in silicon[J].Phys.Status Solidi,1999,171A:301
[26]Lee J S,Yie J E.An XANES study of carbides of molybdenum and tungsten[J].Korean J.Chem.Eng.,1991,8:164
[27]Bachman B J,Vasile M J.Ion bombardment of polyimide films[J].J.Vac.Sci.Technol.,1989,7A:2709
[28]Anwar M,Hogarth C A,Bulpett R.Effect of substrate temperature and film thickness on the surface structure of some thin amorphous films of Mo O3studied by X-ray photoelectron spectroscopy(ESCA)[J].J.Mater.Sci.,1989,24:3087
[29]Shen J Y,Adnot A,Kaliaguine S.An ESCA study of the interaction of oxygen with the surface of ruthenium[J].Appl.Surf.Sci.,1991,51:47
[30]Hammond J S,Gaarenstroom S W,Winograd N.X-ray photoelectron spectroscopic studies of cadmium-and silver-oxygen surfaces[J].Anal.Chem.,1975,47:2193
[31]Mc Evoy A J,Gissler W.ESCA spectra and electronic properties of some ruthenium compounds[J].Phys.Status Solidi,1982,69A:k91
[2]Rosenberg R,Edelstein D C,Hu C K,et al.Copper metallization for high performance silicon technology[J].Annu.Rev.Mater.Sci.,2000,30:229
[3]Semiconductor Industry Association.2005 International Technology Roadmap for Semiconductors[Z].TX,USA:International SEMATECH,2005:1
[4]Chang C A.Formation of copper silicides from Cu(100)/Si(100)and Cu(111)/Si(111)structures[J].J.Appl.Phys.,1990,67:566
[5]Leu L C,Norton D P,Mc Elwee-White L,et al.Ir/Ta N as a bilayer diffusion barrier for advanced Cu interconnects[J].J.Appl.Phys.Lett.,2008,92:111917
[6]Wang J H,Chen L J,Lu Z C,et al.Ta and Ta-N diffusion barriers sputtered with various N2/Ar ratios for Cu metallization[J].J.Vac.Sci.Technol.,2002,20B:1522
[7]Yang L Y,Zhang D H,Li C Y,et al.Comparative study of Ta,Ta N and Ta/Ta N bi-layer barriers for Cu-ultra low-k porous polymer integration[J].Thin Solid Films,2004,462-463:176
[8]Hsu K C,Perng D C,Wang Y C.Robust ultra-thin Ru Mo alloy film as a seedless Cu diffusion barrier[J].J.Alloys.Compd.,2012,516:102
[9]Arunagiri T N,Zhang Y,Chyan O,et al.5 nm ruthenium thin film as a directly plateable copper diffusion barrier[J].Appl.Phys.Lett.,2005,86:083104
[10]Liu B,Zhang Y P,Xu K W.Improvement of thermal stability and electrical property of Cu/Cu(Zr)/Si OC∶H film stack by controlling the structure and composition of Zr(Ge)nano-interlayer[J].Microelectron.Eng.,2014,118:41
[11]Bouhtiyya S,Lucio Porto R,La?k B,et al.Application of sputtered ruthenium nitride thin films as electrode material for energystorage devices[J].Scr.Mater.,2013,68:659
[12]Damayanti M,Sritharan T,Mhaisalkar S G,et al.Effects of dissolved nitrogen in improving barrier properties of ruthenium[J].Appl.Phys.Lett.,2006,88:044101
[13]Jiao G H,Liu B,Li Q R.Investigation of amorphous Ru Mo C alloy films as a seedless diffusion barrier for Cu/p-Si OC∶H ultralowk dielectric integration[J].Appl.Phys.,2015,120A:579
[14]Henderson L B,Ekerdt J G.Time-to-failure analysis of 5 nm amorphous Ru(P)as a copper diffusion barrier[J].Thin Solid Films,2009,517:1645
[15]Hsu K C,Perng D C,Yeh J B,et al.Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects[J].Appl.Surf.Sci.,2012,258:7225
[16]Wojcik H,Krien C,Merkel U,et al.Characterization of Ru-Mn composites for ULSI interconnects[J].Microelectron.Eng.,2013,112:103
[17]Cattaruzza E,Battaglin G,Riello P,et al.On the synthesis of a compound with positive enthalpy of formation:Zinc-blende-like Ru N thin films obtained by rf-magnetron sputtering[J].Appl.Surf.Sci.,2014,320:863
[18]Jansson U,Lewin E.Sputter deposition of transition-metal carbide films-a critical review from a chemical perspective[J].Thin Solid Films,2013,536:1
[19]Trgala M,?emli?ka M,Neilinger P,et al.Superconducting Mo C thin films with enhanced sheet resistance[J].Appl.Surf.Sci.,2014,312:216
[20]Huang Q F,Yoon S F,Rusli,et al.Molybdenum-containing carbon films deposited using the screen grid technique in an electron cyclotron resonance chemical vapor deposition system[J].Diam.Relat.Mater.,2000,9:534
[21]Kacim S,Binst L,Reniers F,et al.Composition and structure of reactively sputter-deposited molybdenum-carbon films[J].Thin Solid Films,1996,287:25
[22]Liu B,Yang J J,Liu C H,et al.Ultrathin Cu Si N/p-Si C∶H bilayer capping barrier for Cu/ultralow-k dielectric integration[J].Appl.Phys.Lett.,2009,94:153116
[23]Laurila T,Zeng K,Kivilahti J K,et al.Chemical stability of Ta diffusion barrier between Cu and Si[J].Thin Solid Films,2000,373:64
[24]Holloway K,Fryer P M,Cabral C Jr,et al.Tantalum as a diffusion barrier between copper and silicon:failure mechanism and effect of nitrogen additions[J].J.Appl.Phys.,1992,71:5433
[25]Seibt M,Hedemann H,Riedel A A,et al.Structural and electrical properties of metal silicide precipitates in silicon[J].Phys.Status Solidi,1999,171A:301
[26]Lee J S,Yie J E.An XANES study of carbides of molybdenum and tungsten[J].Korean J.Chem.Eng.,1991,8:164
[27]Bachman B J,Vasile M J.Ion bombardment of polyimide films[J].J.Vac.Sci.Technol.,1989,7A:2709
[28]Anwar M,Hogarth C A,Bulpett R.Effect of substrate temperature and film thickness on the surface structure of some thin amorphous films of Mo O3studied by X-ray photoelectron spectroscopy(ESCA)[J].J.Mater.Sci.,1989,24:3087
[29]Shen J Y,Adnot A,Kaliaguine S.An ESCA study of the interaction of oxygen with the surface of ruthenium[J].Appl.Surf.Sci.,1991,51:47
[30]Hammond J S,Gaarenstroom S W,Winograd N.X-ray photoelectron spectroscopic studies of cadmium-and silver-oxygen surfaces[J].Anal.Chem.,1975,47:2193
[31]Mc Evoy A J,Gissler W.ESCA spectra and electronic properties of some ruthenium compounds[J].Phys.Status Solidi,1982,69A:k91