Patent Application
20090246952
The field of the invention relates generally to the field of forming a semiconductor device, and more specifically to the use of a cobalt metal barrier film for copper metallization.
An integrated circuit contains various semiconductor devices and a plurality of conducting metal paths that provide electrical power to the semiconductor devices and allow these semiconductor devices to share and exchange information. Within a semiconductor device, metal layers are stacked on top of one another using intermetal or interlayer dielectric layers that insulate the metal layers from each other. Metal layers typically occupy etched pathways in the interlayer dielectric. Normally, each metal layer must form an electrical contact to at least one additional metal layer or conductive layer. Such electrical contact is achieved by etching a hole in the interlayer dielectric that separates the metal layers or a metal layer and a doped substrate region, and filling the resulting via with a metal (plug) to create a vertical interconnect structure. A “via” normally refers to any micro-feature such as a hole, line or other similar feature formed within a dielectric layer that provides an electrical connection through the dielectric layer to a conductive layer underlying the dielectric layer. Similarly, micro-features containing metal layers connecting two or more vias are normally referred to as trenches.
The use of a low resistivity metal such as copper (Cu) provides significant gains in switching delay (RC-delay) and power consumption of integrated circuits. Bulk Cu metal is surrounded by barrier films that separate the bulk Cu metal from dielectric materials and other materials. Cu metal cannot be put in direct contact with dielectric materials since Cu metal has poor adhesion to the dielectric materials and Cu metal is known to easily diffuse into common integrated circuit materials such as silicon and dielectric materials where Cu metal is a mid-bandgap impurity. Furthermore, oxygen can diffuse from an oxygen-containing dielectric material into Cu metal, thereby decreasing the electrical conductivity of the Cu metal. Therefore, a diffusion barrier material is formed on dielectric materials and other materials in the semiconductor device to surround the Cu and prevent diffusion of the Cu into the semiconductor device materials.
However, common diffusion barrier material for Cu metallization have polycrystalline or columnar micro-structures with grain boundaries through which diffusion of oxygen, Cu, and Si can occur, thereby degrading or destroying the integrated circuit. Therefore, micro-structures of diffusion barrier materials need to be controlled to provide improved barrier properties for Cu metallization.
A method is provided for forming a cobalt metal nitride barrier film on a substrate for semiconductor devices. The addition of cobalt (Co) into a metal nitride layer can remove grain boundaries and form a cobalt metal nitride barrier film with a substantially amorphous structure for improved resistance to O, Cu, and Si diffusion into materials used in semiconductor devices.
According to one embodiment of the invention, the method includes providing a substrate in a process chamber; and forming a cobalt metal nitride barrier film on the substrate by depositing a plurality of metal nitride layers, and depositing a cobalt layer between each of the plurality of metal nitride layers.
According to another embodiment of the invention, the method includes providing a substrate in a process chamber; and forming a cobalt metal nitride barrier film on the substrate by simultaneously exposing the substrate to a metal nitride precursor and a cobalt precursor, or exposing the substrate to a metal precursor, a cobalt precursor, and a nitrogen precursor.
According to still another embodiment of the invention, a method is provided for forming a semiconductor device. The method includes providing a substrate containing a dielectric film having a recessed feature; forming a cobalt metal nitride barrier film in the recessed feature; and forming bulk Cu metal over the cobalt metal nitride barrier film in the recessed feature.
According to yet another embodiment of the invention, the method includes providing a substrate containing a dielectric film having a recessed feature; forming a cobalt metal nitride barrier film in the recessed feature; forming a Ru metal film over the cobalt metal nitride barrier film; and forming bulk Cu metal over the Ru metal film in the recessed feature.
The present invention is illustrated by way of example and not as a limitation in the figures of the accompanying drawings.
Formation of cobalt metal nitride barrier films that may be utilized in Cu metallization for semiconductor devices is disclosed in various embodiments. The cobalt metal nitride barrier film may be formed over a surface of recessed feature in a dielectric layer where the recessed feature may have an exposed metallization layer at the bottom of the recessed feature. According to embodiments of the invention, intermixing of cobalt and metal nitride in the cobalt metal nitride film reduces or prevents polycrystalline or columnar film growth and forms a substantially amorphous structure that provides improved diffusion barrier properties against oxygen, Cu, and Si diffusion, for example. The cobalt metal barrier film can further provide lower electrical resistance compared to the corresponding metal nitride material which results in significant gains in switching delay (RC-delay) and power dissipation in the integrated circuit. Furthermore, the cobalt metal nitride barrier film can provide improved adhesion properties to metal layers such as ruthenium (Ru) and Cu.
According to embodiments of the invention, the cobalt metal nitride barrier film can contain metals selected from tantalum (Ta), titanium (Ti), tungsten (W), and other metals suitable for use in diffusion barriers. Furthermore, in addition to nitrogen (N), the cobalt metal nitride barrier film can contain carbon (C), oxygen (O), a halogen (e.g., chlorine (Cl)), and hydrogen (H). In one example, the cobalt metal nitride barrier film may contain a significant amount of C. Films containing both N and C are often referred to as carbonitride films and may contain similar amounts of N and C. In one example, a cobalt tantalum carbonitride barrier film can have Ta:C:N elemental ratios of approximately 2:1:1. In some embodiments, the cobalt metal nitride barrier film can contain at least 5 (and in some embodiments, at least 10, 15, 20, 25, 30, 35, or even at least 40) atomic percent cobalt.
One skilled in the relevant art will recognize that the various embodiments may be practiced without one or more of the specific details, or with other replacement and/or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Similarly, for purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the invention. Nevertheless, the invention may be practiced without specific details. Furthermore, it is understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.
Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, but do not denote that they are present in every embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. Various additional layers and/or structures may be included and/or described features may be omitted in other embodiments.
Various operations will be described as multiple discrete operations in turn, in a manner that is most helpful in understanding the invention. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed and/or described operations may be omitted in additional embodiments.
The processing system 1 may be configured to process 200 mm substrates (wafers), 300 mm substrates, or larger-sized substrates. In fact, it is contemplated that the processing system 1 may be configured to process substrates, wafers, or flat panel displays regardless of their size, as would be appreciated by those skilled in the art. Therefore, while aspects of the invention will be described in connection with the processing of a semiconductor substrate, the invention is not limited solely thereto.
The first process material supply system 40 and the second process material supply system 42 are configured to simultaneously or sequentially introduce a first process material and a second process material to the process chamber 10. Sequential introduction of the first process material and the introduction of the second material can be cyclical, or it may be acyclical with variable time periods between introduction of the first and second process materials. The first process material can, for example, contain a metal precursor or metal nitride precursor selected from a Ta-containing precursor, a Ti-containing precursor, or a W-containing precursor. For instance, the metal precursor or metal nitride precursor can originate as a solid phase, a liquid phase, or a gaseous phase, and it may be delivered to process chamber 10 in a gaseous phase with or without the use of a carrier gas. The second process material can, for example, contain a reducing gas, a nitriding gas, or a combination thereof, and it may be delivered to process chamber 10 with or without the use of a carrier gas. The reducing gas can contain H2, plasma excited H2, or BH3, or a combination of two or more thereof. The nitriding gas can contain NH3, plasma excited NH3, plasma-excited N2, NH(CH3)2, N2H4, or N2H3CH3, or a combination of two or more thereof. The third process material supply system 44 can be configured for introducing a third process material containing a cobalt precursor for depositing a cobalt film containing cobalt metal or a cobalt nitride on the substrate 25.
Additionally, the purge gas supply system 46 can be configured to introduce a purge gas to process chamber 10. For example, the introduction of purge gas may occur between introduction of the first process material and the second process material, following the introduction of the second process material, between the introduction of the second process material and the third process material, and following introduction of the third process material. The purge gas can comprise an inert gas, such as a noble gas (i.e., helium, neon, argon, xenon, krypton), N2, or H2.
Still referring to
Alternatively, the first power source 50 may include a RF generator an impedance match network, and an antenna, such as an inductive coil, through which RF power is coupled to plasma in process chamber 10. The antenna can, for example, include a helical or solenoidal coil, such as in an inductively coupled plasma source or helicon source, or it can, for example, include a flat coil as in a transformer coupled plasma source.
Alternatively, the first power source 50 may include a microwave frequency generator, and may further include a microwave antenna and microwave window through which microwave power is coupled to plasma in process chamber 10. The coupling of microwave power can be accomplished using electron cyclotron resonance (ECR) technology, or it may be employed using surface wave plasma technology, such as a slotted plane antenna (SPA), as described in U.S. Pat. No. 5,024,716, the contents of which are herein incorporated by reference in its entirety.
According to one embodiment of the invention, the processing system 1 includes a substrate bias generation system configured to generate or assist in generating a plasma (through substrate holder biasing) during at least a portion of the deposition of the cobalt metal nitride barrier film. The substrate bias system can include a substrate power source 52 coupled to the process chamber 10, and configured to couple power to substrate 25. The substrate power source 52 may include a RF generator and an impedance match network, and may further include an electrode through which RF power is coupled to substrate 25. The electrode can be formed in substrate holder 20. For instance, substrate holder 20 can be electrically biased at a RF voltage via the transmission of RF power from a RF generator (not shown) through an impedance match network (not shown) to substrate holder 20. A typical frequency for the RF bias can range from about 0.1 MHz to about 100 MHz, and can be 13.56 MHz. RF bias systems for plasma processing are well known to those skilled in the art. Alternatively, RF power is applied to the substrate holder electrode at multiple frequencies. In one example, the substrate power source 52 may generate a plasma in the process chamber 10 through biasing of the substrate holder 20 while the upper assembly 30 is grounded.
Although the plasma generation system and the substrate bias system are illustrated in
Still referring to
In order to improve the thermal transfer between substrate 25 and substrate holder 20, the substrate holder 20 can include a mechanical clamping system, or an electrical clamping system, such as an electrostatic clamping system, to affix substrate 25 to an upper surface of substrate holder 20. Furthermore, substrate holder 20 can further include a substrate backside gas delivery system configured to introduce gas to the back-side of substrate 25 in order to improve the gas-gap thermal conductance between substrate 25 and substrate holder 20. Such a system can be utilized when temperature control of the substrate 25 is required at elevated or reduced temperatures. For example, the substrate backside gas system can comprise a two-zone gas distribution system, wherein the helium gas gap pressure can be independently varied between the center and the edge of substrate 25.
Furthermore, the process chamber 10 is further coupled to a pressure control system 32, including a vacuum pumping system 34 and a valve 36, through a duct 38, wherein the pressure control system 32 is configured to controllably evacuate the process chamber 10 to a pressure suitable for forming the thin film on substrate 25, and suitable for use of the first and second process materials. The vacuum pumping system 34 can include a turbo-molecular vacuum pump (TMP) or a cryogenic pump capable of a pumping speed up to about 5000 liters per second (and greater) and valve 36 can include a gate valve for throttling the chamber pressure. In conventional processing systems, a 300 to 5000 liter per second TMP is generally employed. Moreover, a device for monitoring chamber pressure (not shown) can be coupled to the process chamber 10. The pressure measuring device can, for example, be a capacitance manometer.
The processing system 1 includes a controller 70 that can be used to configure any number of processing elements of the processing system 1, and the controller 70 can collect, provide, process, store, and display data from processing elements. The controller 70 can comprise a number of applications for controlling one or more of the processing elements. For example, controller 70 can include a graphic user interface (GUI) component (not shown) that can provide easy to use interfaces that enable a user to monitor and/or control one or more processing elements. Alternatively, or in addition, controller 70 can be coupled to one or more additional controllers/computers (not shown), and controller 70 can obtain setup and/or configuration information from an additional controller/computer.
The controller 70 can comprise a microprocessor, memory, and a digital I/O port capable of generating control voltages sufficient to communicate and activate inputs of the processing elements of the processing system 1 as well as monitor outputs from the processing system 1. For example, a program stored in the memory may be utilized to activate the inputs to the aforementioned components of the processing system 1 according to a process recipe in order to perform an etching process, or a deposition process.
The controller 70 may be implemented as a general purpose computer system that performs a portion or all of the microprocessor based processing steps of embodiments of the invention in response to a processor executing one or more sequences of one or more instructions contained in a memory. Such instructions may be read into the controller memory from another computer readable medium, such as a hard disk or a removable media drive. One or more processors in a multi-processing arrangement may also be employed as the controller microprocessor to execute the sequences of instructions contained in main memory. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.
The controller 70 includes at least one computer readable medium or memory, such as the controller memory, for holding instructions programmed according to the teachings of the invention and for containing data structures, tables, records, or other data that may be necessary to implement the present invention. Examples of computer readable media are compact discs, hard disks, floppy disks, tape, magneto-optical disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM, SDRAM, or any other magnetic medium, compact discs (e.g., CD-ROM), or any other optical medium, punch cards, paper tape, or other physical medium with patterns of holes, a carrier wave (described below), or any other medium from which a computer can read.
Stored on any one or on a combination of computer readable media, the present invention includes software for controlling the controller 70, for driving a device or devices for implementing embodiments the invention, and/or for enabling the controller to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems, development tools, and applications software. Such computer readable media further includes the computer program product of the present invention for performing all or a portion (if processing is distributed) of the processing performed in implementing embodiments of the invention.
The computer code devices of the present invention may be any interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs), Java classes, and complete executable programs. Moreover, parts of the processing of the present invention may be distributed for better performance, reliability, and/or cost.
The term “computer readable medium” as used herein refers to any medium that participates in providing instructions to the processor of the controller 70 for execution. A computer readable medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical, magnetic disks, and magneto-optical disks, such as the hard disk or the removable media drive. Volatile media includes dynamic memory, such as the main memory. Moreover, various forms of computer readable media may be involved in carrying out one or more sequences of one or more instructions to processor of controller for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions for implementing all or a portion of the present invention remotely into a dynamic memory and send the instructions over a network to the controller 70.
The controller 70 may be locally located relative to the processing system 1, or it may be remotely located relative to the processing system 1. For example, the controller 70 may exchange data with the processing system 1 using at least one of a direct connection, an intranet, the Internet and a wireless connection. The controller 70 may be coupled to an intranet at, for example, a customer site (i.e., a device maker, etc.), or it may be coupled to an intranet at, for example, a vendor site (i.e., an equipment manufacturer). Additionally, for example, the controller 70 may be coupled to the Internet. Furthermore, another computer (i.e., controller, server, etc.) may access, for example, the controller 70 to exchange data via at least one of a direct connection, an intranet, and the Internet. As also would be appreciated by those skilled in the art, the controller 70 may exchange data with the processing system 1 via a wireless connection.
In
According to embodiments of the invention, the cobalt metal nitride barrier film 204 may be formed using a metal precursor or a metal nitride precursor, a cobalt source, and a reducing gas and/or a nitriding gas in CVD, PECVD, ALD, or PEALD, or a combination thereof. In one example, a metal nitride precursor can contain tantalum and nitrogen but a separate nitrogen precursor (e.g., NH3 or plasma-excited N2) may be added as an additional source of nitrogen.
In ALD and PEALD processing, a substrate temperature is selected below the thermal decomposition temperature to sequentially adsorb a metal precursor or metal nitride precursor, and a cobalt precursor on the substrate surface in a self-limiting manner, where the adsorption stops when the thickness of the adsorbed precursor corresponds to about one atomic layer or less. The thermal decomposition temperature of the selected metal precursor or metal nitride and cobalt precursor may be determined by experimentation or obtained from the literature. In CVD processing, a substrate temperature is selected that is above the thermal decomposition temperature of the precursors to react and deposit a film on the surface in a non-limiting manner, where the deposition stops when the precursor exposure ends.
A wide variety of Ta-containing precursors may be utilized for depositing tantalum nitride (or carbonitride) layers for a cobalt tantalum nitride barrier film 204. The Ta-containing precursors may be selected from tantalum nitride precursors and tantalum precursors. Tantalum nitride (or carbonitride) precursor can contain both tantalum and nitrogen in the same molecule but a separate nitrogen precursor (e.g., NH3 or plasma-excited N2) may be added as an additional source of nitrogen. Representative examples of tantalum nitride precursor containing “Ta—N” intra-molecular bonds include Ta(NMe2)3(NCMe2Et) (TAIMATA), Ta(NEt2)5 (PDEAT), Ta(NMe2)5 (PDMAT), Ta(NEtMe)5 (PEMAT), (tBuN)Ta(NMe2)3 (TBTDMT), (tBuN)Ta(NEt2)3 (TBTDET), (tBuN)Ta(NEtMe)3 (TBTEMT), and (iPrN)Ta(NEt2)3 (IPTDET). Tantalum precursors can include TaF5 and TaCl5 and precursors containing “Ta—C” intra-molecular bonds include, for example, Ta(η5-C5H5)2H3, Ta(CH2)(CH3)(η5-C5H5)2, Ta(η3-C3H5) (η5-C5H5)2, Ta(CH3)3(η5-C5H5)2, Ta(CH3)4(η5-C5(CH3)5), or Ta(η5-C5(CH3)5)2H3.
The Ti-containing precursors may be selected from titanium nitride precursors and titanium precursors. Titanium nitride (or carbonitride) precursors can contain both titanium and nitrogen in the same molecule but a separate nitrogen precursor (e.g., NH3 or plasma-excited N2) may be added as an additional source of nitrogen. Representative examples of titanium nitride precursor having “Ti—N” intra-molecular bonds include Ti(NEt2)4 (TDEAT), Ti(NMeEt)4 (TEMAT), Ti(NMe2)4 (TDMAT). Titanium precursors can include TiF5 and TiCl5 and precursors containing “Ti—C” intra-molecular bonds include, for example, Ti(COCH3)(η5-C5H5)2Cl, Ti(η5-C5H5)Cl2, Ti(η5-C5H5)Cl3, Ti(η5-C5H5)2Cl2, Ti(η5-C5(CH3)5)Cl3, Ti(CH3)(η5-C5H5)2Cl, Ti(η5C9H7)2Cl2, Ti((η5-C5(CH3)5)2Cl, Ti((η5-C5(CH3)5)2Cl2, Ti(η5-C5H5)2(μ-Cl)2, Ti(η5-C5H5)2(CO)2, Ti(CH3)3(η5-C5H5), Ti(CH3)2(η5-C5H5)2, Ti(CH3)4, Ti(η5-C5H5)(η7-C7H7), Ti(η5-C5H5)(η8-C8H8), Ti(C5H5)2(η5-C5H5)2, Ti((C5H5)2)2(η-H)2, Ti(η5-C5(CH3)5)2, Ti(η5-C5(CH3)5)2(H)2, and Ti(CH3)2(η5(CH3)5)2.
Examples of W-containing precursors include WF6, W(CO)6, and bis(tert-butylimido)bis(dimethylamido)tungsten ((tBuN)2(Me2N)2W).
Embodiments of the invention may utilize a wide variety of cobalt precursors for depositing cobalt. Examples include Co2(CO)8, CoCp(CO)2, Co(CO)3(NO), dicobalt hexacarbonyl t-butylacetylene (Co(CO)6(HCCtBu), Co(acac)2, Co(Cp)2, bis(pentamethylcyclopentadienyl)cobalt(II) (Co(Me5Cp)2), bis(ethylcyclopentadienyl)cobalt(II) (Co(EtCp)2), cobalt(II) hexafluoroacetylacetonate hydrate, cobalt tris(2,2,6,6-tetramethyl-3,5-heptanedionate), cobalt(III) acetylacetonate, bis(N,N′-diisopropylacetamidinato)cobalt, and tricarbonyl allyl cobalt.
Next, the substrate is exposed to a cobalt precursor to deposit cobalt on the metal nitride layer(s). Next, the metal nitride deposition and the cobalt deposition may be repeated a second number of times until the cobalt metal nitride barrier film has a desired thickness. A thickness of the cobalt metal nitride barrier film 204 can, for example, be between about 1 nm and about 10 nm, or between about 2 nm and about 5 nm, for example about 4 nm. The second number of times can, for example, be between 1 and 100, between 1 and 20, or between 1 and 5. In one example, the process 600 may end with an exposure to the reducing and/or nitriding gas. In another example, the process may end with an exposure to the cobalt precursor.
In one embodiment, the first number of times may be used to control the relative amounts of the metal nitride and cobalt in the deposited cobalt metal nitride barrier film. In one example, the first number of times may be varied following each cobalt precursor exposure to vary the cobalt content throughout a thickness of the cobalt metal nitride barrier film 204, thereby forming a graded cobalt metal nitride barrier film 204 with increasing or decreasing cobalt content throughout the film 204.
During deposition of the cobalt metal nitride barrier film 204, the intermixing ratios of metal nitride and the cobalt may be affected by controlling the thickness of the alternating metal nitride and cobalt layers. The deposited cobalt metal nitride barrier film may be post-annealed in order to further intermix the metal nitride and cobalt layers to form an amorphous cobalt metal nitride barrier film 204 with desired electrical and materials properties. In one example, the cobalt metal nitride barrier film 204 may be annealed at a temperature between 200° C. and 500° C.
In one example, a plurality of tantalum nitride layers may be deposited by PEALD using alternating exposures of TAIMATA and plasma-excited H2. The tantalum nitride layers may contain similar amounts of N and C, for example as TaC0.5N0.5. The TAIMATA exposures may utilize a substrate temperature below the TAIMATA thermal decomposition temperature of about 300° C., for example between about 150° C. and less than 300° C. Exemplary TAIMATA exposure times can be between 0.1 and 10 seconds, and exemplary plasma-excited H2 exposure times can be between 1 and 30 seconds.
In one embodiment, the third and fourth number of times may be used to control the relative amounts of the metal nitride and cobalt in the deposited cobalt metal nitride barrier film 204. In one example, the third and/or the fourth number of times may be varied during the process 602 to vary the cobalt content throughout a thickness of the cobalt metal nitride barrier film 204, thereby forming a graded cobalt metal nitride barrier film 204 with increasing or decreasing cobalt content throughout the film 204.
In one example, the cobalt metal nitride barrier film 204 may be deposited by PEALD using the process 604, including alternating exposures of TAIMATA, a cobalt source, and plasma-excited H2. The TAIMATA exposures may utilize a substrate temperature below the thermal decomposition temperature of about 300° C., for example between about 150° C. and less than 300° C. Exemplary TAIMATA exposure times can be between 0.1 and 10 seconds, and exemplary plasma-excited H2 exposure times can be between 1 and 30 seconds.
According to one embodiment of the invention, the cobalt metal nitride film 204 may be deposited using CVD by simultaneously exposing the substrate to a metal nitride precursor or a metal precursor, a cobalt precursor, and a reducing gas, nitriding gas, or a combination thereof.
Referring now to
In another example, formation of the bulk Cu metal 206 may include depositing a Cu seed layer (not shown) on the cobalt metal nitride barrier film 204, and subsequently plating bulk Cu metal on the Cu seed layer. The Cu seed layer can provide a Cu growth surface for the Cu plating process. A thickness of the Cu seed layer can, for example, be between about 0.5 nm and about 20 nm, or between about 1 nm and about 3 nm, for example about 2 nm. The Cu seed layer may be deposited by sputtering methods, for example by ionized physical vapor deposition (IPVD). An exemplary IPVD system is described in U.S. Pat. No. 6,287,435. In one example, the Cu seed layer 130 may be deposited using a capacitively coupled plasma (CCP) system where a Cu sputtering target forms an upper electrode and a substrate holder upon which the substrate is positioned forms a lower electrode. However, other types of plasma systems can be used.
In one example, the Ru metal film 306 may be deposited using a Ru CVD system and method described U.S. Pat. No. 7,270,848, entitled METHOD AND DEPOSITION SYSTEM FOR INCREASING DEPOSITION RATES OF METAL LAYERS FROM METAL-CARBONYL PRECURSORS, the entire content of which is herein incorporated by reference. In other examples, the Ru metal film 306 may be deposited using ruthenium metalorganic precursors, for example (2,4-dimethylpentadienyl)(ethylcyclopentadienyl)ruthenium (Ru(DMPD)(EtCp)), bis(2,4-dimethylpentadienyl)ruthenium (Ru(DMPD)2), 4-dimethylpentadienyl)(methylcyclopentadienyl)ruthenium (Ru(DMPD)(MeCp)), and bis(ethylcyclopentadienyl)ruthenium (Ru(EtCp)2), as well as combinations of these and other precursors. In another example, the Ru metal film 306 may be deposited by Ru ALD. Still other examples for depositing the Ru metal film 306 include sputtering methods using a solid Ru metal target.
According to an embodiment of the invention, the recessed feature 724 can be a via having an aspect ratio (depth/width) greater than or equal to about 2:1, for example 3:1, 4:1, 5:1, 6:1, 12:1, 15:1, or higher. The via can have widths of about 200 nm or less, for example 150 nm, 90 nm, 64 nm, 45 nm, 32 nm, 20 nm, or lower. However, embodiments of the invention are not limited to these aspect ratios or via widths, as other aspect ratios and via widths may be utilized.
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According to another embodiment of the invention, the Ru metal film 728 and the cobalt metal nitride barrier film 726 at the bottom of the recessed feature 727 depicted in
An exemplary recessed feature 724 was illustrated and described above in
A plurality of embodiments for formation of a cobalt metal nitride barrier film on a substrate and semiconductor devices containing a cobalt metal nitride barrier film have been described. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. This description and the claims following include terms that are used for descriptive purposes only and are not to be construed as limiting. For example, the term “on” as used herein (including in the claims) does not require that a first film “on” a second film is directly on and in immediate contact with the second film unless such is specifically stated; there may be a third film or other structure between the first film and the second film on the first film.
Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teaching. Persons skilled in the art will recognize various equivalent combinations and substitutions for various components shown in the Figures. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
This application is related to co-pending U.S. patent application Ser. No. 11/839,410, entitled “SEMICONDUCTOR DEVICE CONTAINING AN ALUMINUM TANTALUM CARBONITRIDE BARRIER FILM AND METHOD OF FORMING,” filed on Aug. 15, 2007, the entire content of which is hereby incorporated by reference.
