Cobalt deposition on barrier surfaces

Abstract

Embodiments of the invention provide processes for depositing a cobalt layer on a barrier layer and subsequently depositing a conductive material, such as copper or a copper alloy, thereon. In one embodiment, a method for depositing materials on a substrate surface is provided which includes forming a barrier layer on a substrate, exposing the substrate to dicobalt hexacarbonyl butylacetylene (CCTBA) and hydrogen to form a cobalt layer on the barrier layer during a vapor deposition process (e.g., CVD or ALD), and depositing a conductive material over the cobalt layer. In some examples, the barrier layer and/or the cobalt layer may be exposed to a gas or a reagent during a treatment process, such as a thermal process, an in situ plasma process, or a remote plasma process.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the invention generally relate to a metallization process for manufacturing electronic and semiconductor devices, more particularly, embodiments relate to a method for depositing a cobalt layer on a barrier layer before depositing a conductive layer or contact material thereon.

2. Description of the Related Art

Copper is the current metal of choice for use in multilevel metallization processes that are crucial to device manufacturing. The multilevel interconnects that drive the manufacturing processes require planarization of high aspect ratio apertures including contacts, vias, lines, and other features. Filling the features without creating voids or deforming the feature geometry is more difficult when the features have higher aspect ratios. Reliable formation of interconnects is also more difficult as manufacturers strive to increase circuit density and quality.

As the use of copper has permeated the marketplace because of its relative low cost and processing properties, semiconductor manufacturers continue to look for ways to improve the boundary regions between copper and dielectric material by reducing copper diffusion and dewetting. Several processing methods have been developed to manufacture copper interconnects as feature sizes have decreased. Each processing method may increase the likelihood of errors such as copper diffusion across boundary regions, copper crystalline structure deformation, and dewetting. Physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), electrochemical plating (ECP), electroless deposition, chemical mechanical polishing (CMP), electrochemical mechanical polishing (ECMP), and other methods of depositing and removing copper layers utilize mechanical, electrical, or chemical methods to manipulate the copper that forms the interconnects. Barrier and capping layers may be deposited to contain the copper.

In the past, a layer of tantalum, tantalum nitride, or copper alloy with tin, aluminum, or magnesium was used to provide a barrier layer or an adhesion promoter between copper and other materials. These options are usually costly and are only partially effective. As the copper atoms along the boundary regions experience changes in temperature, pressure, atmospheric conditions, or other process variables common during multiple step semiconductor processing, the copper may migrate along the boundary regions and become agglomerated copper. The copper may also be less uniformly dispersed along the boundary regions and become dewetted copper. These changes in the boundary region include stress migration and electromigration of the copper atoms. The stress migration and electromigration of copper across the dielectric layers or other structures increases the resistivity of the resulting structures and reduces the reliability of the resulting devices.

Therefore, a need exists to enhance the stability and adhesion of a conductive layer or a contact material on a barrier layer. Also, a need exists to improve the electromigration reliability of a copper-containing layer, especially for copper line formations, while preventing the diffusion of copper into neighboring materials, such as dielectric materials.

SUMMARY OF THE INVENTION

Embodiments of the invention provide processes for depositing a cobalt layer on a barrier layer prior to depositing a conductive layer thereon. In one embodiment, a method for depositing materials on a substrate surface is provided which includes forming a barrier layer on a substrate, exposing the substrate to dicobalt hexacarbonyl butylacetylene (CCTBA) and hydrogen (H₂) to form a cobalt layer on the barrier layer during a vapor deposition process, and depositing a conductive material over the cobalt layer.

In one example, the substrate may be exposed to a deposition gas containing CCTBA and hydrogen during a thermal CVD process. In another example, the substrate may be sequentially exposed to CCTBA and hydrogen during an ALD process. The substrate may be heated to a temperature within a range from about 100° C. to about 250° C. during the CVD or ALD process. The cobalt layer may be deposited with a thickness of less than about 40 Å.

In some examples, the barrier layer and/or the cobalt layer may be exposed to a gas or a reagent during a treatment process. The treatment may be a thermal process, an in situ plasma process, or a remote plasma process. The gas or the reagent may contain or be nitrogen (N₂), ammonia (NH₃), hydrogen (H₂), an ammonia/hydrogen mixture, silane, disilane, helium, argon, plasmas thereof, derivatives thereof, or combinations thereof. The barrier layer or the cobalt layer may be exposed to the gas, reagent, or plasma for a time period within a range from about 1 second to about 30 seconds. The substrate may be heated to a temperature within a range from about 50° C. to about 400° C. during the treatment process.

In some examples, the conductive material may contain copper or a copper alloy. The conductive material may contain a seed layer and a bulk layer. Alternatively, the conductive material may be directly deposited on the cobalt layer, such as by an electrochemical plating (ECP) process. In one example, a seed layer containing copper may be deposited by a PVD process or a CVD process. In another example, the bulk layer contains copper and may be deposited by an ECP process. The barrier layer may contain tantalum, tantalum nitride, titanium, titanium nitride, tungsten, tungsten nitride, alloys thereof, derivatives thereof, or combinations thereof. In one example, the barrier layer may be a tantalum nitride layer disposed on a tantalum layer.

In another embodiment, a method for depositing materials on a substrate surface is provided which includes forming a barrier layer on a substrate, exposing the barrier layer to a first plasma during a pre-treatment process, exposing the substrate to CCTBA and hydrogen to form a cobalt layer on the barrier layer during a vapor deposition process, exposing the cobalt layer to a second plasma during a post-treatment process, and depositing a copper layer on the cobalt layer by a vapor deposition process, such as a PVD process or a CVD process.

In another embodiment, a method for depositing materials on a substrate surface is provided which includes forming a barrier layer on a substrate, exposing the barrier layer to a plasma during a pre-treatment process, exposing the substrate to CCTBA and a reducing gas to form a cobalt layer on the barrier layer during a vapor deposition process, exposing the cobalt layer to a hydrogen plasma during a post-treatment process, and depositing a copper material over the cobalt layer. In one example, the vapor deposition process to deposit the cobalt layer and the post-treatment process are sequentially repeated to form a cobalt material. The cobalt material contains multiple cobalt layers which have each been exposed to a hydrogen plasma prior to having another cobalt layer deposited thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1 depicts a flow chart illustrating a process according to an embodiment described herein; and

FIGS. 2A-2F depict schematic views of a substrate at different process steps according to an embodiment described herein.

DETAILED DESCRIPTION

Embodiments of the invention provide a method for depositing a cobalt layer on a barrier layer or layer prior to depositing a conductive layer thereon. The cobalt layer and barrier layer may each optionally be exposed to a treatment process, such as a plasma process or a thermal process. The conductive layer may contain copper or a copper alloy and be deposited by a physical vapor deposition (PVD) process, an atomic layer deposition (ALD) process, an electrochemical plating (ECP) process, or an electroless deposition process. The cobalt layer improves copper boundary region properties to promote adhesion, improve gapfill and electromigration performance, decrease diffusion and agglomeration, and encourage uniform roughness and wetting of the substrate surface during processing.

FIG. 1 depicts a flow chart illustrating process 100 according to an embodiment of the invention. Process 100 may be used to form an interconnect or other device on a substrate. In one embodiment, steps 110-150 of process 100 may be performed on substrate 200, depicted in FIGS. 2A-2F. Process 100 includes depositing or forming a barrier layer on a substrate (step 110), optionally exposing the barrier layer to a pre-treatment process (step 120), depositing a cobalt layer on the barrier layer (step 130), optionally exposing the cobalt layer to a post-treatment process (step 140), and depositing at least one conductive layer on the cobalt layer (step 150).

FIG. 2A depicts substrate 200 containing dielectric layer 204 disposed over underlayer 202. Aperture 206 is formed within dielectric layer 204 and may be a via, damascene, trough, or other passageway formed therein. Underlayer 202 may be a substrate, substrate surface, contact layer, or another layer depending on device structure. Dielectric layer 204 may contain a dielectric material, such as a low-k dielectric material. In one example, dielectric layer 204 contains a low-k dielectric material, such as a silicon carbide oxide material, or a carbon doped silicon oxide material, for example, BLACK DIAMOND® II low-k dielectric material, available from Applied Materials, Inc., located in Santa Clara, Calif. Another example of a suitable material for dielectric layer 204 is a silicon carbide based film formed using chemical vapor deposition (CVD) or plasma enhanced CVD (PE-CVD) processes such as described in commonly assigned U.S. Pat. Nos. 6,537,733, 6,790,788, and 6,890,850, which are incorporated herein by reference.

In one embodiment, at least one barrier layer or material may be deposited or formed on a substrate during step 110 of process 100. In one example, FIG. 2B depicts barrier layer 210 disposed on substrate 200, over dielectric layer 204, and conformally within aperture 206. Barrier layer 210 may be one layer or multiple layers. Barrier layer 210 may contain titanium, titanium nitride, tantalum, tantalum nitride, tungsten, tungsten nitride, silicides thereof, derivatives thereof, or combinations thereof. In some embodiments, barrier layer 210 may contain a bilayer of tantalum/tantalum nitride, titanium/titanium nitride, or tungsten/tungsten nitride. Barrier layer 210 may have a thickness within a range from about 5 Å to about 50 Å, preferably, from about 10 Å to about 30 Å, and may be formed or deposited by PVD, ALD, plasma enhanced ALD (PE-ALD), CVD, PE-CVD, pulsed-CVD, or combinations thereof.

In one example, barrier layer 210 contains a lower layer of metallic tantalum deposited by a PVD process and an upper layer disposed over the lower layer of tantalum nitride layer deposited by another PVD process. In another example, barrier layer 210 contains a lower layer of metallic tantalum deposited by an ALD process and an upper layer disposed over the lower layer of tantalum nitride layer deposited by a CVD process. In another example, barrier layer 210 contains a lower layer of metallic tantalum deposited by a PVD process and an upper layer disposed over the lower layer of tantalum nitride layer deposited by a CVD process.

For example, barrier layer 210 may contain tantalum nitride deposited using a CVD process or an ALD process wherein tantalum-containing compound or tantalum precursor (e.g., PDMAT) and nitrogen precursor (e.g., ammonia) are reacted. In one embodiment, tantalum and/or tantalum nitride is deposited as barrier layer 210 by an ALD process as described in commonly assigned U.S. Ser. No. 10/281,079, filed Oct. 25, 2002, and published as US 2003-0121608, which is herein incorporated by reference. In one example, a Ta/TaN bilayer may be deposited as barrier layer 210, such as a metallic tantalum layer and a tantalum nitride layer that are independently deposited by ALD, CVD, and/or PVD processes, one layer on top of the other layer, in either order.

In another example, a Ti/TiN bilayer may be deposited as barrier layer 210, such as a metallic titanium layer and a titanium nitride layer that are independently deposited by ALD, CVD, and/or PVD processes, one layer on top of the other layer, in either order. In another example, a W/WN bilayer may be deposited as barrier layer 210, such as a metallic tungsten layer and a tungsten nitride layer that are independently deposited by ALD, CVD, and/or PVD processes, one layer on top of the other layer, in either order.

At step 120, barrier layer 210 may be optionally exposed to a pre-treatment process, such as a plasma process or a thermal process. Process gases and/or reagents that may be exposed to substrate 200 during plasma or thermal pre-treatment processes include hydrogen (e.g., H₂ or atomic-H), nitrogen (e.g., N₂ or atomic-N), ammonia (NH₃), a hydrogen and ammonia mixture (H₂/NH₃), hydrazine (N₂H₄), silane (SiH₄), disilane (Si₂H₆), helium, argon, derivatives thereof, plasmas thereof, or combinations thereof. The process gas may flow into the processing chamber or be exposed to the substrate having a flow rate within a range from about 500 sccm to about 10 slm, preferably, from about 1 slm to about 6 slm, for example, about 3 slm.

In one embodiment, substrate 200 and barrier layer 210 may be exposed to a plasma to remove contaminants from barrier layer 210 during the pre-treatment process at step 120. Substrate 200 may be positioned within a processing chamber and exposed to a process gas which is ignited to form the plasma. The process gas may contain one gaseous compound or multiple gaseous compounds. Substrate 200 may be at room temperature (e.g., 23° C.), but is usually preheated to the desired temperature of the subsequent deposition process. Substrate 200 may be heated to a temperature within a range from about 100° C. to about 400° C., preferably, from about 125° C. to about 350° C., and more preferably, from about 150° C. to about 300° C., such as about 200° C. or about 250° C.

The processing chamber may produce an in situ plasma or be equipped with a remote plasma source (RPS). In one embodiment, substrate 200 may be exposed to the plasma (e.g., in situ or remotely) for a time period within a range from about 0.5 seconds to about 90 seconds, preferably, from about 10 seconds to about 60 seconds, and more preferably, from about 20 seconds to about 40 seconds. The plasma may be produced at a power within a range from about 100 watts to about 1,000 watts, preferably, from about 200 watts to about 600 watts, and more preferably, from about 300 watts to about 500 watts. The processing chamber usually has an internal pressure of about 100 Torr or less, such as within a range from about 0.1 Torr to about 100 Torr, preferably, from about 0.5 Torr to about 50 Torr, and more preferably, from about 1 Torr to about 10 Torr.

In one example, substrate 200 and barrier layer 210 may be exposed to a plasma generated from hydrogen, ammonia, nitrogen, or mixtures thereof. In another example, substrate 200 and barrier layer 210 may be exposed to a plasma generated from hydrogen and ammonia. In another example, substrate 200 and barrier layer 210 may be exposed to a plasma generated from hydrogen, nitrogen, silane, disilane, or mixtures thereof. In another example, substrate 200 and barrier layer 210 may be exposed to a plasma generated from hydrogen, nitrogen, argon, helium, or mixtures thereof.

In another embodiment, substrate 200 and barrier layer 210 are exposed to a process gas to remove contaminants from barrier layer 210 during a thermal pre-treatment process at step 120. The thermal pre-treatment process may be a rapid thermal process (RTP) or a rapid thermal annealing (RTA) process. Substrate 200 may be positioned within a processing chamber and exposed to at least one process gas and/or reagent. The processing chamber may be a deposition chamber that will be used for a subsequent deposition process, such as a PVD chamber, a CVD chamber, or an ALD chamber. Alternatively, the processing chamber may be a thermal annealing chamber, such as the RADIANCE® RTA chamber, commercially available from Applied Materials, Inc., Santa Clara, Calif. Substrate 200 may be heated to a temperature within a range from about 25° C. to about 800° C., preferably, from about 50° C. to about 400° C., and more preferably, from about 100° C. to about 300° C. Substrate 200 may be heated for a time period within a range from about 2 minutes to about 20 minutes, preferably, from about 5 minutes to about 15 minutes. For example, substrate 200 may be heated to about 400° C. for about 12 minutes within the processing chamber.

In one example, substrate 200 and barrier layer 210 may be exposed to hydrogen, ammonia, nitrogen, or mixtures thereof while being heated within the processing chamber. In another example, substrate 200 and barrier layer 210 may be exposed to an ammonia/hydrogen mixture while being heated within the processing chamber. In another example, substrate 200 and barrier layer 210 may be exposed to hydrogen, nitrogen, silane, disilane, or mixtures thereof while being heated within the processing chamber. In another example, substrate 200 and barrier layer 210 may be exposed to hydrogen, nitrogen, argon, helium, or mixtures thereof while being heated within the processing chamber.

In another embodiment, at least cobalt material or layer may be deposited or formed on the substrate during step 130 of process 100. In one example, FIG. 2C depicts cobalt layer 220 disposed on substrate 200, over barrier layer 210, and conformally within aperture 206. Cobalt layer 220 is usually a single layer, but may contain multiple layers. Cobalt layer 220 may be a continuous layer or a discontinuous layer across barrier layer 210. Cobalt layer 220 may have a thickness of about 40 Å or less, such as within a range from about 2 Å to about 40 Å, preferably, from about 5 Å to about 30 Å. Cobalt layer 220 may be formed or deposited by a vapor deposition process, such as CVD, PE-CVD, pulsed-CVD, ALD, PE-ALD, or PVD. The plasma enhanced vapor deposition process, namely PE-CVD and PE-ALD, may be an in situ plasma process within the processing chamber or may be a remote plasma process such that a plasma is ignited in by a RPS and directed into the processing chamber. In many examples, cobalt layer 220 contains metallic cobalt. Alternatively, in other examples, cobalt layer 220 may contain one or more cobalt materials, such as metallic cobalt, cobalt silicide, cobalt boride, cobalt phosphide, alloys thereof, derivatives thereof, or combinations thereof.

In some embodiments, cobalt layer 220 may be formed or deposited by simultaneously introducing a cobalt precursor and a reagent into the processing chamber during a thermal CVD process, a pulsed-CVD process, a PE-CVD process, or a pulsed PE-CVD process. In other embodiments, the cobalt precursor may be introduced into the processing chamber without a reagent during a thermal CVD process, a pulsed-CVD process, a PE-CVD process, or a pulsed PE-CVD process. Alternatively, in other embodiments, cobalt layer 220 may be formed or deposited by sequentially introducing a cobalt precursor and a reagent into the processing chamber during a thermal ALD process or a PE-ALD process.

Cobalt layer 220 may contain metallic cobalt in some examples, but may contain other cobalt materials in other examples. Suitable cobalt precursors for forming cobalt materials (e.g., metallic cobalt or cobalt alloys) by CVD or ALD processes described herein include cobalt carbonyl complexes, cobalt amidinates compounds, cobaltocene compounds, cobalt dienyl complexes, cobalt nitrosyl complexes, derivatives thereof, complexes thereof, plasmas thereof, or combinations thereof. In some embodiments, cobalt materials may be deposited by CVD and ALD processes further described in commonly assigned U.S. Pat. Nos. 7,264,846 and 7,404,985, which are herein incorporated by reference.

In some embodiments, cobalt carbonyl compounds or complexes may be utilized as cobalt precursors. Cobalt carbonyl compounds or complexes have the general chemical formula (CO)_xCo_yL_z, where X may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, Y may be 1, 2, 3, 4, or 5, and Z may be 1, 2, 3, 4, 5, 6, 7, or 8. The group L is absent, one ligand or multiple ligands, that may be the same ligand or different ligands, and include cyclopentadienyl, alkylcyclopentadienyl (e.g., methylcyclopentadienyl or pentamethylcyclopentadienyl), pentadienyl, alkylpentadienyl, cyclobutadienyl, butadienyl, ethylene, allyl (or propylene), alkenes, dialkenes, alkynes, acetylene, butylacetylene, nitrosyl, ammonia, derivatives thereof, complexes thereof, plasmas thereof, or combinations thereof.

In one embodiment, dicobalt hexacarbonyl acetyl compounds may be used to form cobalt materials (e.g., cobalt layer 220) during a deposition process. Dicobalt hexacarbonyl acetyl compounds may have the chemical formula of (CO)₆Co₂(RC≡CR′), wherein R and R′ are independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl, tertbutyl, penta, benzyl, aryl, isomers thereof, derivatives thereof, or combinations thereof. In one example, dicobalt hexacarbonyl butylacetylene (CCTBA, (CO)₆Co₂(HC≡C^tBu)) is the cobalt precursor. Other examples of dicobalt hexacarbonyl acetyl compounds include dicobalt hexacarbonyl methyl butylacetylene ((CO)₆Co₂(MeC≡C^tBu)), dicobalt hexacarbonyl phenylacetylene ((CO)₆Co₂(HC≡CPh)), hexacarbonyl methyl phenylacetylene ((CO)₆Co₂(MeC≡CPh)), dicobalt hexacarbonyl methylacetylene ((CO)₆Co₂(HC≡CMe)), dicobalt hexacarbonyl dimethylacetylene ((CO)₆Co₂(MeC≡CMe)), derivatives thereof, complexes thereof, plasmas thereof, or combinations thereof. Other exemplary cobalt carbonyl complexes include cyclopentadienyl cobalt bis(carbonyl) (CpCo(CO)₂), tricarbonyl allyl cobalt ((CO)₃Co(CH₂CH═CH₂)), derivatives thereof, complexes thereof, plasmas thereof, or combinations thereof.

In another embodiment, cobalt amidinates or cobalt amido complexes may be utilized as cobalt precursors. Cobalt amido complexes have the general chemical formula (RR′N)_xCo, where X may be 1, 2, or 3, and R and R′ are independently hydrogen, methyl, ethyl, propyl, butyl, alkyl, silyl, alkylsilyl, derivatives thereof, or combinations thereof. Some exemplary cobalt amido complexes include bis(di(butyldimethylsilyl)amido) cobalt (((BuMe₂Si)₂N)₂Co), bis(di(ethyldimethylsilyl)amido) cobalt (((EtMe₂Si)₂N)₂Co), bis(di(propyldimethylsilyl)amido) cobalt (((PrMe₂Si)₂N)₂Co), bis(di(trimethylsilyl)amido) cobalt (((Me₃Si)₂N)₂Co), tris(di(trimethylsilyl)amido) cobalt (((Me₃Si)₂N)₃Co), derivatives thereof, complexes thereof, plasmas thereof, or combinations thereof.

Some exemplary cobalt precursors include methylcyclopentadienyl cobalt bis(carbonyl) (MeCpCo(CO)₂), ethylcyclopentadienyl cobalt bis(carbonyl) (EtCpCo(CO)₂), pentamethylcyclopentadienyl cobalt bis(carbonyl) (Me₅CpCo(CO)₂), dicobalt octa(carbonyl) (Co₂(CO)₈), nitrosyl cobalt tris(carbonyl) ((ON)Co(CO)₃), bis(cyclopentadienyl) cobalt, (cyclopentadienyl) cobalt (cyclohexadienyl), cyclopentadienyl cobalt (1,3-hexadienyl), (cyclobutadienyl) cobalt (cyclopentadienyl), bis(methylcyclopentadienyl) cobalt, (cyclopentadienyl) cobalt (5-methylcyclopentadienyl), bis(ethylene) cobalt (pentamethylcyclopentadienyl), cobalt tetracarbonyl iodide, cobalt tetracarbonyl trichlorosilane, carbonyl chloride tris(trimethylphosphine) cobalt, cobalt tricarbonyl-hydrotributylphosphine, acetylene dicobalt hexacarbonyl, acetylene dicobalt pentacarbonyl triethylphosphine, derivatives thereof, complexes thereof, plasmas thereof, or combinations thereof.

In some examples, alternative reagents, including reducing agents, may be used to react with cobalt precursors while forming cobalt materials (e.g., metallic cobalt or cobalt alloys) by processes described herein include hydrogen (e.g., H₂ or atomic-H), nitrogen (e.g., N₂ or atomic-N), ammonia (NH₃), hydrazine (N₂H₄), a hydrogen and ammonia mixture (H₂/NH₃), borane (BH₃), diborane (B₂H₆), triethylborane (Et₃B), silane (SiH₄), disilane (Si₂H₆), trisilane (Si₃H₈), tetrasilane (Si₄H₁₀), methyl silane (SiCH₆), dimethylsilane (SiC₂H₈), phosphine (PH₃), derivatives thereof, plasmas thereof, or combinations thereof.

In one embodiment, cobalt layer 220 containing metallic cobalt is deposited by simultaneously exposing substrate 200 to a cobalt precursor gas and a reducing agent during a thermal CVD process. In an alternative embodiment, cobalt layer 220 containing metallic cobalt is deposited by simultaneously exposing substrate 200 to a cobalt precursor gas and a reducing agent gas during a plasma enhanced CVD process. The plasma source may be an in situ plasma source within the CVD chamber or a RPS positioned outside of the CVD chamber. The cobalt precursor gas may be formed by passing a carrier gas (e.g., nitrogen or argon) through an ampoule of a cobalt precursor (e.g., CCTBA). The reducing agent gas may be a single compound (e.g., H₂), and therefore have no carrier gas. Alternatively, the reducing agent gas may be formed by passing a carrier gas through an ampoule of a reducing agent.

The ampoule may be heated depending on the cobalt precursor or reducing agent used during the process. In one example, an ampoule containing a cobalt precursor, such as a dicobalt hexacarbonyl acetyl compound or other cobalt carbonyl compound (e.g., (CO)_xCo_yL_z) may be heated to a temperature within a range from about 30° C. to about 500° C. The cobalt precursor gas usually has a flow rate within a range from about 100 sccm (standard cubic centimeters per minute) to about 2,000 sccm, preferably, from about 200 sccm to about 1,000 sccm, and more preferably, from about 300 sccm to about 700 sccm, for example, about 500 sccm. The reducing agent gas usually has a flow rate within a range from about 0.5 slm (standard liters per minute) to about 10 slm, preferably, from about 1 slm to about 8 slm, and more preferably, from about 2 slm to about 6 slm. In one example, reducing agent gas is hydrogen and has a flow rate within a range from about 2 slm to about 6 slm, such as about 4 slm.

The cobalt precursor gas and the reducing agent gas may be combined to form a deposition gas prior to, while, or subsequent to entering the processing chamber during a deposition process to deposit cobalt layer 220. Substrate 200 may be positioned within a processing chamber and heated to a temperature within a range from about 25° C. to about 800° C., preferably, from about 50° C. to about 400° C., and more preferably, from about 100° C. to about 250° C., such as about 150° C. Once at a predetermined temperature, substrate 200 may be exposed to the deposition gas containing the cobalt precursor gas and the reducing agent gas for a time period within a range from about 0.1 seconds to about 120 seconds, preferably, from about 1 second to about 60 seconds, and more preferably, from about 5 seconds to about 30 seconds. For example, substrate 200 may be heated to about 150° C. for about 10 minutes within the processing chamber while forming cobalt layer 220 during the CVD process.

At step 140, cobalt layer 220 may be optionally exposed to a post-treatment process, such as a plasma process or a thermal process. Process gases and/or reagents that may be exposed to substrate 200 and cobalt layer 220 during plasma or thermal post-treatment processes include hydrogen (e.g., H₂ or atomic-H), nitrogen (e.g., N₂ or atomic-N), ammonia (NH₃), a hydrogen and ammonia mixture (H₂/NH₃), hydrazine (N₂H₄), silane (SiH₄), disilane (Si₂H₆), helium, argon, derivatives thereof, plasmas thereof, or combinations thereof. The process gas may flow into the processing chamber or be exposed to the substrate having a flow rate within a range from about 500 sccm to about 10 slm, preferably, from about 1 slm to about 6 slm, for example, about 3 slm.

In one embodiment, substrate 200 and cobalt layer 220 are exposed to a plasma to remove contaminants from cobalt layer 220 during the post-treatment process at step 140. Substrate 200 may be positioned within a processing chamber and exposed to a process gas which is ignited to form the plasma. The process gas may contain one gaseous compound or multiple gaseous compounds. Substrate 200 may be at room temperature (e.g., 23° C.), but is usually preheated to the desired temperature of the subsequent deposition process. Substrate 200 may be heated to a temperature within a range from about 100° C. to about 400° C., preferably, from about 125° C. to about 350° C., and more preferably, from about 150° C. to about 300° C., such as about 200° C. or about 250° C.

The processing chamber may produce an in situ plasma or be equipped with a RPS. In one embodiment, substrate 200 may be exposed to the plasma (e.g., in situ or remotely) for a time period within a range from about 0.5 seconds to about 90 seconds, preferably, from about 10 seconds to about 60 seconds, and more preferably, from about 20 seconds to about 40 seconds. The plasma may be produced at a power within a range from about 100 watts to about 1,000 watts, preferably, from about 200 watts to about 600 watts, and more preferably, from about 300 watts to about 500 watts. The processing chamber usually has an internal pressure of about 100 Torr or less, such as within a range from about 0.1 Torr to about 100 Torr, preferably, from about 0.5 Torr to about 50 Torr, and more preferably, from about 1 Torr to about 10 Torr.

In one example, substrate 200 and cobalt layer 220 may be exposed to a plasma generated from hydrogen, ammonia, nitrogen, or mixtures thereof. In another example, substrate 200 and cobalt layer 220 may be exposed to a plasma generated from hydrogen and ammonia. In another example, substrate 200 and cobalt layer 220 may be exposed to a plasma generated from hydrogen, nitrogen, silane, disilane, or mixtures thereof. In another example, substrate 200 and cobalt layer 220 may be exposed to a plasma generated from hydrogen, nitrogen, argon, helium, or mixtures thereof.

In some examples, substrate 200 and cobalt layer 220 may be exposed to a hydrogen plasma generated from hydrogen gas ignited by a RPS. Cobalt layer 220 may be exposed to hydrogen gas with a flow rate within a range from about 2 slm to about 4 slm. The processing chamber may have an internal pressure within a range from about 1 Torr to about 10 Torr, and the plasma is ignited by a RPS having a power within a range from about 300 watts to about 500 watts. In one embodiment, the plasma may be exposed to cobalt layer 220 for a time period within a range from about 20 seconds to about 40 seconds for every deposited layer of cobalt material having a thickness within a range from about 7 Å to about 10 Å. Multiple treatments may be performed sequentially with the multiple layers of deposited cobalt material while forming cobalt layer 220.

In another embodiment, substrate 200 and cobalt layer 220 are exposed to a process gas to remove contaminants from cobalt layer 220 during a thermal post-treatment process at step 140. The thermal post-treatment process may be a RTP or a RTA process. Substrate 200 may be positioned within a processing chamber and exposed to at least one process gas and/or reagent. The processing chamber may be a deposition chamber that was used in a prior deposition process or will be used for a subsequent deposition process, such as a PVD chamber, a CVD chamber, or an ALD chamber. Alternatively, the processing chamber may be a thermal annealing chamber, such as the RADIANCE® RTA chamber, commercially available from Applied Materials, Inc., Santa Clara, Calif. Substrate 200 may be heated to a temperature within a range from about 25° C. to about 800° C., preferably, from about 50° C. to about 400° C., and more preferably, from about 100° C. to about 300° C. Substrate 200 may be heated for a time period within a range from about 2 minutes to about 20 minutes, preferably, from about 5 minutes to about 15 minutes. For example, substrate 200 may be heated to about 400° C. for about 12 minutes within the processing chamber.

In one example, substrate 200 and cobalt layer 220 may be exposed to hydrogen, ammonia, nitrogen, or mixtures thereof while being heated within the processing chamber. In another example, substrate 200 and cobalt layer 220 may be exposed to an ammonia/hydrogen mixture while being heated within the processing chamber. In another example, substrate 200 and cobalt layer 220 may be exposed to hydrogen, nitrogen, silane, disilane, or mixtures thereof while being heated within the processing chamber. In another example, substrate 200 and cobalt layer 220 may be exposed to hydrogen, nitrogen, argon, helium, or mixtures thereof while being heated within the processing chamber.

FIG. 2C depicts aperture 206 formed within dielectric layer 204 on substrate 200. Aperture 206 contains barrier layer 210 and cobalt layer 220 conformally disposed therein. In another embodiment, during step 150 of process 100, a conductive layer may be deposited or formed on or over cobalt layer 220. In one embodiment, the conductive layer is bulk layer 240 which may be directly deposited over cobalt layer 220, as depicted in FIG. 2D. Alternatively, in another embodiment, the conductive layer is seed layer 230 and bulk layer 240. Seed layer 230 may be deposited over cobalt layer 220 and subsequently, bulk layer 240 may be deposited over seed layer 230, as depicted in FIGS. 2E-2F.

Seed layer 230 and bulk layer 240 may be deposited or formed during a single deposition process or multiple deposition processes. Seed layer 230 may contain copper, tungsten, aluminum, ruthenium, cobalt, silver, platinum, palladium, alloys thereof, derivatives thereof or combinations thereof. Bulk layer 240 may contain copper, tungsten, aluminum, alloys thereof, derivatives thereof or combinations thereof. Usually, seed layer 230 and bulk layer 240 may independently contain copper, tungsten, aluminum, alloys thereof, derivatives thereof or combinations thereof. Seed layer 230 and bulk layer 240 may independently be deposited by using one or more deposition process, such as a CVD process, an ALD process, a PVD process, an electroless deposition process, an ECP process, derivatives thereof, or combinations thereof.

In one example, each of seed layer 230 and bulk layer 240 contains copper or a copper alloy. For example, seed layer 230 containing copper may be formed on cobalt layer 220 by a PVD process and thereafter, bulk layer 240 containing copper may be deposited to fill aperture 206 by an ECP process or an electroless deposition process. In another example, seed layer 230 containing copper may be formed on cobalt layer 220 by an ALD process and thereafter, bulk layer 240 containing copper may be deposited to fill aperture 206 by an ECP process or an electroless deposition process. In another example, seed layer 230 containing copper may be formed on cobalt layer 220 by a CVD process and thereafter, bulk layer 240 containing copper may be deposited to fill aperture 206 by an ECP process or an electroless deposition process. In another example, seed layer 230 containing copper may be formed on cobalt layer 220 by an electroless process and thereafter, bulk layer 240 containing copper may be deposited to fill aperture 206 by an ECP process or an electroless deposition process. In another example, cobalt layer 220 serves as a seed layer to which bulk layer 240 containing copper may be directly deposited to fill aperture 206 by an ECP process or an electroless deposition process.

In one example, each of seed layer 230 and bulk layer 240 contains tungsten or a tungsten alloy. For example, seed layer 230 containing tungsten may be formed on cobalt layer 220 by a PVD process and thereafter, bulk layer 240 containing tungsten may be deposited to fill aperture 206 by a CVD process or a pulsed-CVD process. In another example, seed layer 230 containing tungsten may be formed on cobalt layer 220 by an ALD process and thereafter, bulk layer 240 containing tungsten may be deposited to fill aperture 206 by a CVD process or a pulsed-CVD process. In another example, seed layer 230 containing tungsten may be formed on cobalt layer 220 by a pulsed-CVD process and thereafter, bulk layer 240 containing tungsten may be deposited to fill aperture 206 by a CVD process or a pulsed-CVD process. In another example, seed layer 230 containing tungsten may be formed on cobalt layer 220 by an electroless process and thereafter, bulk layer 240 containing tungsten may be deposited to fill aperture 206 by a CVD process or a pulsed-CVD process. In another example, cobalt layer 220 serves as a seed layer to which bulk layer 240 containing tungsten may be directly deposited to fill aperture 206 by a CVD process or a pulsed-CVD process.

An ALD processing chamber used during embodiments described herein is available from Applied Materials, Inc., located in Santa Clara, Calif. A detailed description of an ALD processing chamber may be found in commonly assigned U.S. Pat. Nos. 6,916,398 and 6,878,206, commonly assigned U.S. Ser. No. 10/281,079, filed on Oct. 25, 2002, and published as U.S. Pub. No. 2003-0121608, and commonly assigned U.S. Ser. Nos. 11/556,745, 11/556,752, 11/556,756, 11/556,758, 11/556,763, each filed Nov. 6, 2006, and published as U.S. Pub. Nos. 2007-0119379, 2007-0119371, 2007-0128862, 2007-0128863, and 2007-0128864, which are hereby incorporated by reference in their entirety. In another embodiment, a chamber configured to operate in both an ALD mode as well as a conventional CVD mode may be used to deposit cobalt-containing materials is described in commonly assigned U.S. Pat. No. 7,204,886, which is incorporated herein by reference in its entirety. A detailed description of an ALD process for forming cobalt-containing materials is further disclosed in commonly assigned U.S. Pat. Nos. 7,264,846 and 7,404,985, which are hereby incorporated by reference in their entirety. In other embodiments, a chamber configured to operate in both an ALD mode as well as a conventional CVD mode that may be used to deposit cobalt-containing materials is the TXZ® showerhead and CVD chamber available from Applied Materials, Inc., located in Santa Clara, Calif. An example of a suitable vapor deposition chamber includes the WXZ™ CVD chamber, commercially available from Applied Materials, Inc., located in Santa Clara, Calif. The vapor deposition chamber may be adapted to deposit materials by conventional CVD, pulsed-CVD, or PE-CVD techniques as well as by ALD and PE-ALD techniques. Also, the vapor deposition chamber may be used as for treatment processes, such as an in situ plasma process, a remote plasma process, or a thermal annealing process.

“Substrate surface” or “substrate,” as used herein, refers to any substrate or material surface formed on a substrate upon which film processing is performed during a fabrication process. For example, a substrate surface on which processing may be performed include materials such as monocrystalline, polycrystalline or amorphous silicon, strained silicon, silicon on insulator (SOI), doped silicon, silicon germanium, germanium, gallium arsenide, glass, sapphire, silicon oxide, silicon nitride, silicon oxynitride, and/or carbon doped silicon oxides, such as SiO_xC_y, for example, BLACK DIAMOND® low-k dielectric, available from Applied Materials, Inc., located in Santa Clara, Calif. Substrates may have various dimensions, such as 100 mm, 200 mm, 300 mm, or 450 mm diameter wafers, as well as, rectangular or square panes. Unless otherwise noted, embodiments and examples described herein are usually conducted on substrates with a 200 mm diameter or a 300 mm diameter, more preferably, a 300 mm diameter. Processes of the embodiments described herein may be used to deposit cobalt materials (e.g., metallic cobalt) on many substrates and surfaces, especially, barrier layers and layers. Substrates on which embodiments of the invention may be useful include, but are not limited to semiconductor wafers, such as crystalline silicon (e.g., Si<100> or Si<111>), silicon oxide, strained silicon, silicon germanium, doped or undoped polysilicon, doped or undoped silicon wafers, and patterned or non-patterned wafers. Substrates may be exposed to a pre-treatment process to polish, etch, reduce, oxidize, hydroxylate, heat, and/or anneal the substrate or substrate surface.

While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method for depositing materials on a substrate surface, comprising: forming a barrier layer on a substrate, wherein the barrier layer is a tantalum nitride layer, a titanium nitride layer, or combinations thereof and is deposited by a physical vapor deposition process or a chemical vapor deposition process;exposing the substrate to dicobalt hexacarbonyl butylacetylene (CCTBA) and hydrogen to form a cobalt layer on the barrier layer during a thermal chemical vapor deposition process, wherein the cobalt layer is metallic cobalt, cobalt boride, cobalt phosphide, or combinations thereof; anddepositing a conductive material over the cobalt layer, wherein the conductive material comprises copper or a copper alloy.

2. The method of claim 1, further comprising exposing the barrier layer or the cobalt layer to a plasma during a treatment process, wherein the plasma is formed from nitrogen (N2), ammonia (NH3), hydrogen (H2), or combinations thereof.

3. The method of claim 2, wherein the barrier layer or the cobalt layer is exposed to a hydrogen plasma for a time period within a range from about 20 seconds to about 40 seconds and the hydrogen plasma is formed by a remote plasma source.

4. The method of claim 1, further comprising exposing the barrier layer or the cobalt layer to a gas during a thermal treatment process, wherein the gas is nitrogen (N2), ammonia (NH3), hydrogen (H2), or combinations thereof.

5. The method of claim 4, wherein the substrate is heated to a temperature within a range from about 50 degrees Celsius to about 400 degrees Celsius during the thermal treatment process.

6. The method of claim 1, wherein the substrate is heated to a temperature within a range from about 100 degrees Celsius to about 250 degrees Celsius during the thermal chemical vapor deposition process.

7. The method of claim 1, wherein the barrier layer is a tantalum nitride layer disposed on a tantalum layer.

8. The method of claim 1, wherein the conductive material comprises copper or a copper alloy.

9. The method of claim 8, wherein the conductive material comprises a seed layer and a bulk layer.

10. The method of claim 9, wherein the seed layer comprises copper and is deposited by a physical vapor deposition process or a chemical vapor deposition process.

11. The method of claim 10, wherein the bulk layer comprises copper and is deposited by an electrochemical plating process.

12. The method of claim 1, wherein the conductive material is directly deposited on the cobalt layer by an electrochemical plating process.

13. A method for depositing materials on a substrate surface, comprising: forming a barrier layer on a substrate, wherein the barrier layer is a tantalum nitride layer, a titanium nitride layer, or combinations thereof and is deposited by a physical vapor deposition process or a chemical vapor deposition process;exposing the substrate to dicobalt hexacarbonyl butylacetylene (CCTBA) and hydrogen to form a cobalt layer on the barrier layer during a thermal chemical vapor deposition process;exposing the cobalt layer to a plasma during a post-treatment process; anddepositing a copper material on the cobalt layer by a vapor deposition process, wherein the cobalt layer is metallic cobalt, cobalt boride, cobalt phosphide, or combinations thereof.

14. The method of claim 13, wherein the plasma is formed from nitrogen (N2), ammonia (NH3), hydrogen (H2), argon, helium, or combinations thereof.

15. The method of claim 14, wherein the cobalt layer is exposed to the plasma for a time period within a range from about 20 seconds to about 40 seconds, and the plasma is formed by a remote plasma source.

16. The method of claim 13, wherein the substrate is heated to a temperature within a range from about 100 degrees Celsius to about 250 degrees Celsius during the thermal chemical vapor deposition process.

17. The method of claim 13, wherein the barrier layer is a tantalum nitride layer disposed on a tantalum layer.

18. The method of claim 13, wherein the copper material comprises a seed layer and a bulk layer.

19. The method of claim 18, wherein the seed layer is deposited by a physical vapor deposition process or a chemical vapor deposition process and the bulk layer is deposited by an electrochemical plating process.

20. A method for depositing materials on a substrate surface, comprising: forming a barrier layer on a substrate, wherein the barrier layer is a tantalum nitride layer, a titanium nitride layer, or combinations thereof and is deposited by a physical vapor deposition process or a chemical vapor deposition process;exposing the substrate to dicobalt hexacarbonyl butylacetylene (CCTBA) and a reducing gas to form a cobalt layer on the barrier layer during a vapor deposition process;exposing the cobalt layer to a hydrogen plasma during a post-treatment process; anddepositing a copper material over the cobalt layer, wherein the cobalt layer is metallic cobalt, cobalt boride, cobalt phosphide, or combinations thereof.