This application is based on and claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2021-0104813, filed on Aug. 9, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
The present disclosure relates to interconnect structures and/or electronic devices including the interconnect structures.
In recent years, the size of semiconductor devices has been gradually reduced to increase the degree of integration, and to this end, reducing the line width of copper wiring in interconnect structures may be required. However, a decrease in the line width of copper wiring may cause an increase in the current density of the copper wiring, which may cause an increase in the resistance of the copper wiring. In addition, the increase in the resistance of the copper wiring may cause electromigration of copper atoms, and thus, defects may occur in the copper wiring. Therefore, to lower the resistance of copper wiring and prevent electromigration of the copper atoms, a cap layer capable of improving the electromigration resistance of copper wiring may be required.
Provided are interconnect structures and/or electronic devices including the interconnect structures.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.
According to an embodiment, an interconnect structure may include: a dielectric layer including a trench; a conductive line in the trench; and a first cap layer on an upper surface of the conductive line. The first cap layer may include a graphene-metal composite including graphene and a metal mixed with each other.
In some embodiments, the graphene-metal composite may include metal particles dispersed in the graphene.
In some embodiments, the graphene-metal composite may include graphene particles dispersed in the metal.
In some embodiments, the graphene-metal composite may have a carbon content profile in which a carbon content gradually decreases in a direction from the graphene to the metal.
In some embodiments, the graphene may include intrinsic graphene or nanocrystalline graphene.
In some embodiments, the metal may include at least one of Ru, Co, Ti, Ta, Al, Rh, Ir, and Pt.
In some embodiments, the graphene-metal composite may include the metal in an amount of about 1 at% to about 80 at%.
In some embodiments, the first cap layer may have a thickness of about 3 nm or less.
In some embodiments, the conductive line may include at least one of a metal element, a metal alloy, and a combination thereof. The conductive line may include at least one of Cu, Ru, Al, Co, W, Mo, Ti, Ta, Ni, Pt, Cr, Rh, Ir, Pd, and Os.
In some embodiments, the dielectric layer may include a dielectric material having a dielectric constant of about 3.6 or less.
In some embodiments, the interconnect structure may further include a second cap layer inside the trench on a lateral surface of the conductive line and a lower surface of the conductive line. The second cap layer may include the graphene-metal composite.
In some embodiments, the interconnect structure may further include a barrier layer on the conductive line inside the trench.
In some embodiments, the barrier layer may cover a lateral surface of the conductive line and a lower surface of the conductive line. The barrier layer may additionally cover the upper surface of the conductive line.
In some embodiments, the barrier layer may include a metal element, a metal alloy, a metal nitride, or graphene.
In some embodiments, the interconnect structure may further include a second cap layer on a lateral surface of the barrier layer and a lower surface of the barrier layer. The second cap layer may include the graphene-metal composite.
In some embodiments, the interconnect structure may further include a second cap layer on a lateral surface of the barrier layer and the second cap layer may include the graphene-metal composite.
In some embodiments, the interconnect structure may further include a second cap layer on a lower surface of the barrier layer and the second cap layer may include the graphene-metal composite.
According to an embodiment, an electronic device may include the interconnect structure.
According to an embodiment, an interconnect structure may include: a dielectric layer including a trench; a conductive line in the trench; and a cap layer on the dielectric layer. The cap layer may include a graphene-metal composite including graphene and a metal mixed with each other. The cap layer may be on the conductive line.
In some embodiments, the graphene-metal composite may include one of: metal particles dispersed in the graphene; graphene particles dispersed in the metal; or a carbon content profile in which a carbon content gradually decreases in a direction from the graphene to the metal.
In some embodiments, the cap layer may be in the trench.
In some embodiments, the conductive line may be between the cap layer and the dielectric layer.
In some embodiments, the cap layer may directly contact a surface of the conductive line.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, “at least one of A, B, and C,” and similar language (e.g., “at least one selected from the group consisting of A, B, and C”) may be construed as A only, B only, C only, or any combination of two or more of A, B, and C, such as, for instance, ABC, AB, BC, and AC.
Hereinafter, example embodiments will be described with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the sizes of elements may be exaggerated for clarity of illustration. The embodiments described herein are for illustrative purposes only, and various modifications may be made therein.
In the following description, when an element is referred to as being “above” or “on” another element, it may be directly on an upper, lower, left, or right side of the other element while making contact with the other element or one or more intervening elements may be present such that the element may be above an upper, lower, left, or right side of the other element without making direct contact with the other element.
The terms of a singular form may include plural forms unless otherwise mentioned. It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features or elements, but do not preclude the presence or addition of one or more other features or elements.
An element referred to with the definite article or a demonstrative pronoun may be construed as the element or the elements even though it has a singular form. Operations of a method may be performed in an appropriate order unless explicitly described in terms of order or described to the contrary, and are not limited to the stated order thereof.
In the present disclosure, terms such as “unit” or “module” may be used to denote a unit that has at least one function or operation and is implemented with hardware, software, or a combination of hardware and software.
Furthermore, line connections or connection members between elements depicted in the drawings represent functional connections and/or physical or circuit connections by way of example, and in actual applications, they may be replaced or embodied with various additional functional connections, physical connections, or circuit connections.
When the terms “about” or “substantially” are used in this specification in connection with a numerical value, it is intended that the associated numerical value includes a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical value. Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. Further, regardless of whether numerical values or shapes are modified as “about” or “substantially,” it will be understood that these values and shapes should be construed as including a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical values or shapes.
Examples or example terms are just used herein to describe technical ideas and should not be considered for purposes of limitation unless defined by the claims.
Referring to
The substrate may be a semiconductor substrate. For example, the substrate may include a Group IV semiconductor material, a Group III/V semiconductor compound, or a Group II/VI semiconductor compound. For example, the substrate may include Si, Ge, SiC, SiGe, SiGeC, a Ge alloy, GaAs, InAs, InP, or the like. However, this is merely an example, and the substrate may include various semiconductor materials other than the listed materials.
Examples of the substrate may include a silicon-on-insulator (SOI) substrate and a silicon germanium-on-insulator (SGOT) substrate. In addition, the substrate may include a non-doped semiconductor material or a doped semiconductor material.
The substrate may include at least one semiconductor device (not shown). The semiconductor device may include, for example, at least one selected from the group consisting of a transistor, a capacitor, a diode, and a resistor. However, embodiments are not limited thereto.
The dielectric layer 120 is formed on the substrate. The dielectric layer 120 may have a single-layer structure or a multi-layer structure in which different materials are stacked. The dielectric layer 120 may include a dielectric material used in a general semiconductor manufacturing process. For example, the dielectric layer 120 may include a dielectric material having a dielectric constant of about 3.6 or less. For example, the dielectric layer 120 may include a silicon oxide, a nitride, silicon nitride, silicon carbide, a silicate, or the like. However, this is merely an example, and the dielectric layer 120 may include various dielectric materials other than the listed materials. In addition, the dielectric layer 120 may include an organic dielectric material.
A trench 120a may be formed in the dielectric layer 120 to a desired and/or alternatively predetermined depth. The conductive line 140 may fill the inside of the trench 120a. The conductive line 140 may include one selected from the group consisting of a metal, a metal alloy, and a combination thereof. Here, the metal may include, for example, at least one selected from the group consisting of Cu, Ru, Al, Co, W, Mo, Ti, Ta, Ni, Pt, Cr, Rh, Ir, Pd, and Os. However, embodiments are not limited thereto, and the conductive line 140 may include various other metals.
The cap layer 150 may be provided on an upper surface of the conductive line 140 which is filled in the trench 120a. The cap layer 150 may cover an exposed surface of the conductive line 140, that is, the upper surface of the conductive line 140. The cap layer 150 may reduce the resistance of the conductive line 140 and improve the electromigration resistance of the conductive line 140, such that the interconnect structure 100 may be more reliably used.
The cap layer 150 may include a graphene-metal composite in which graphene and a metal are mixed with each other. Here, the graphene of the graphene-metal composite may include intrinsic graphene or nanocrystalline graphene.
The intrinsic graphene may be crystalline graphene and may include crystals larger than about 100 nm. In addition, the nanocrystalline graphene may include crystals, which are smaller than the crystals of the intrinsic graphene. For example, the nanocrystalline graphene may include crystals having a size of about 0.5 nm to about 100 nm.
When measured by X-ray photoelectron spectroscopy (XPS) analysis, the ratio of carbon having an sp2 bonding structure to the total carbon in the intrinsic graphene may be about 100%. The intrinsic graphene may contain substantially no hydrogen. The density of the intrinsic graphene may be, for example, about 2.1 g/cc.
For example, the ratio of carbon having an sp2 bonding structure to the total carbon in the nanocrystalline graphene may be about 50% to about 99%. In addition, the nanocrystalline graphene may include hydrogen in an amount of, for example, about 1 at% (atomic percent) to about 20 at%. In addition, the density of the nanocrystalline graphene may be, for example, about 1.6 g/cc to about 2.1 g/cc.
For example, the metal of the graphene-metal composite may include at least one selected from the group consisting of Ru, Co, Ti, Ta, Al, Rh, Ir, and Pt. However, embodiments are not limited thereto. The content of the metal in the graphene-metal composite may be about 1 at % to about 80 at %. However, embodiments are not limited thereto.
In the current embodiment, the cap layer 150 may include a graphene-metal composite, which includes graphene 151 and metal particles 152 dispersed in the graphene 151. Here, the metal particles 152 may have a nanoscale size, but is not limited thereto. The cap layer 150 may have a thickness of about 3 nm or less. However, embodiments are not limited thereto.
A barrier layer 130 may be provided on inner walls of the trench 120a. Here, the barrier layer 130 may be provided between the dielectric layer 120 and the conductive line 140 to cover lateral and lower surfaces of the conductive line 140. The barrier layer 130 may have a function of limiting and/or preventing diffusion of a material of the conductive line 140. In addition, the barrier layer 130 may additionally function as an adhesive layer between the dielectric layer 120 and the conductive line 140.
The barrier layer 130 may include a single-layer structure or a multi-layer structure in which a plurality of layers of different materials are stacked. The barrier layer 130 may include, for example, a metal, a metal alloy, a metal nitride, or the like. For example, the barrier layer 130 may include Ta, Ti, Ru, RuTa, IrTa, W, TaN, TiN, RuN, IrTaN, TiSiN, Co, Mn, MnO, WN, or the like. However, these materials are examples, and the barrier layer 130 may include various materials other than the listed materials. For example, the barrier layer 130 may include the aforementioned graphene (intrinsic graphene or nanocrystalline graphene). A liner layer (not shown) may be further provided between the conductive line 140 and the barrier layer 130 for improving adhesion between the conductive line 140 and the barrier layer 130.
In the interconnect structure 100 of the current embodiment, the cap layer 150 includes a graphene-metal composite in which graphene and a metal are mixed with each other, thereby reducing the resistance of the conductive line 140 and improving the electromigration resistance of the conductive line 140 as described below. Thus, the interconnect structure 100 may be more reliably used.
Referring to
The dielectric layer 120 may include, for example, a dielectric material having a dielectric constant of about 3.6 or less. For example, the dielectric layer 120 may include any one of silicon oxide, a nitride, silicon nitride, silicon carbide, a silicate, or the like. However, this is merely an example. The dielectric layer 120 may have a single-layer structure or a multi-layer structure in which different materials are stacked.
Next, a trench 120a may be formed in the dielectric layer 120 to a given depth. The trench 120a may be formed through, for example, a photolithography process and an etching process.
Next, a barrier layer 130 may be formed on inner walls of the trench 120a. Here, the barrier layer 130 may be formed through a deposition process used in a general semiconductor manufacturing process. The barrier layer 130 may include, for example, a metal, a metal alloy, a metal nitride, graphene, or the like. However, embodiments are not limited thereto. The barrier layer 130 may include a single-layer structure or a multi-layer structure in which a plurality of layers are stacked.
Referring to
The conductive line 140 may include one of a metal, a metal alloy, or a combination thereof. Here, the metal may include, for example, at least one selected from the group consisting of Cu, Ru, Al, Co, W, Mo, Ti, Ta, Ni, Pt, Cr, Rh, Ir, Pd, and Os. However, embodiments are not limited thereto. Then, upper surfaces of the dielectric layer 120, the barrier layer 130, and the conductive line 140 may be processed through a planarization process. Here, the planarization process may include, for example, a chemical mechanical polishing (CMP) process, a grinding process, or the like, but is not limited thereto.
Referring to
The metal layer 162 may be deposited on an upper surface of the graphene layer 161. The metal layer 162 may include, for example, at least one selected from the group consisting of Ru, Co, Ti, Ta, Al, Rh, Ir, and Pt. However, embodiments are not limited thereto.
Then, when a heat treatment process is performed on the structure shown in
That is, as shown in
In the above, the graphene-metal composite is formed by sequentially depositing the graphene layer 161 and the metal layer 162 on the upper surface of the conductive line 140 and then performing the heat treatment process thereon. However, this is merely an example, and in another example, a graphene precursor and a metal precursor may be used together in a CVD process to form a graphene-metal composite on the upper surface of the conductive line 140.
Referring to
In the current embodiment, the cap layer 150 formed on the conductive line 140 includes a graphene-metal composite in which graphene having a resistance reducing effect and a metal having a reliability improving effect are mixed with each other, thereby improving reliability by reducing the resistance of the conductive line 140 and improving the electromigration resistance of the second metal layer 140.
Referring to
The cap layer 250 may include a graphene-metal composite. For example, the cap layer 250 may include a metal 252 and graphene particles 251 dispersed in the metal 252. The cap layer 250 may have a thickness of about 3 nm or less, but is not limited thereto. The metal content of the graphene-metal composite of the cap layer 250 may be about 1 at % to about 80 at %.
Referring to
The cap layer 350 may include a graphene-metal composite. For example, the cap layer 350 may include a graphene-metal composite having a carbon content profile in which the content of carbon gradually decreases in a direction from graphene 351 to a metal 352. The graphene 351 may be formed in a lower portion of the cap layer 350, and the metal 352 may be formed in an upper portion of the cap layer 350. In addition, the content of carbon between the graphene 351 and the metal 352 may be adjusted such that the content of carbon may gradually decrease in a direction from the graphene 351 to the metal 352.
Referring to
The first cap layer 450a may cover an upper surface of the conductive line 440. Here, the first cap layer 450a may include a graphene-metal composite in which graphene and a metal are mixed with each other. The first cap layer 450a may have a thickness of about 3 nm or less, but is not limited thereto.
The graphene of the graphene-metal composite may include intrinsic graphene or nanocrystalline graphene. In the intrinsic graphene, the ratio of carbon having an sp2 bonding structure to the total carbon may be substantially 100%. The intrinsic graphene may include substantially no hydrogen. The density of the intrinsic graphene may be, for example, about 2.1 g/cc. Furthermore, in the nanocrystalline graphene, the ratio of carbon having an sp2 bonding structure to the total carbon may be, for example, about 50% to about 99%. In addition, the nanocrystalline graphene may include hydrogen in an amount of, for example, about 1 at % to about 20 at %. In addition, the density of the nanocrystalline graphene may be, for example, about 1.6 g/cc to 2.1 g/cc.
The metal of the graphene-metal composite may include, for example, at least one of (or selected from the group consisting of) Ru, Co, Ti, Ta, Al, Rh, Ir, and Pt. However, embodiments are not limited thereto. The metal content of the graphene-metal. composite may be about 1 at % to 80 at %. However, embodiments are not limited thereto.
The first cap layer 450a may be one of the cap layers 150, 250, and 350 described in the embodiments above. For example, the first cap layer 450a may include a graphene-metal composite including graphene and metal particles dispersed in the graphene. Alternatively, the first cap layer 450a may include a graphene-metal composite including a metal and graphene particles dispersed in the metal. Alternatively, the first cap layer 450a may include a graphene-metal composite having a carbon content profile in which the content of carbon gradually decreases in a direction from graphene to a metal.
The second cap layer 450b may be provided on lateral surfaces and a lower surface of the conductive line 440. The second cap layer 450b may be provided inside the trench 120a to cover the lateral surfaces and the lower surface of the conductive line 440. Like the first cap layer 450a, the second cap layer 450b may include a graphene-metal composite in which graphene and a metal are mixed with each other.
In current embodiment, the first cap layer 450a is provided on the upper surface of the conductive line 440, and the second cap layer 450b is additionally provided on the lower surface and the lateral surfaces of the conductive line 440, thereby enhancing a resistance reducing effect and a reliability improving effect. The second cap layer 450b may also function as a barrier layer.
Referring to
The barrier layer 530 may be provided on inner walls of the trench 120a. The barrier layer 530 may include, for example, a metal, a metal alloy, a metal nitride, graphene, or the like. For example, the barrier layer 530 may include Ta, Ti, Ru, RuTa, IrTa, W, TaN, TiN, RuN, IrTaN, TiSiN, Co, Mn, MnO, WN, or the like. However, this is merely an example, and the barrier layer 530 may include various materials other than the listed materials.
The first cap layer 550a may be provided on an upper surface of the conductive line 540. As described above, the first cap layer 550a may include a graphene-metal composite in which graphene and a metal are mixed with each other. The first cap layer 550a may be one of the cap layers 150, 250, and 350 described in the embodiments above. The second cap layer 550b may be provided on the barrier layer 530. The second cap layer 550b may be provided between the barrier layer 530 and the conductive line 540 to cover the lateral surfaces and the lower surface of the conductive line 540. Like the first cap layer 550a, the second cap layer 550b may include a graphene-metal composite in which graphene and a metal are mixed with each other.
Referring to
The barrier layer 630 may be provided inside the trench 120a to cover lateral surfaces and a lower surface of the conductive line 640. The barrier layer 630 may include, for example, a metal, a metal alloy, a metal nitride, graphene, or the like.
The first cap layer 650a may be provided on an upper surface of the conductive line 640 and an upper surface of the barrier layer 630. As described above, the first cap layer 650a may include a graphene-metal composite in which graphene and a metal are mixed with each other. The first cap layer 650a may be one of the cap layers 150, 250, and 350 described in the embodiments above. The second cap layer 650b may be provided on inner walls of the trench 120a. The second cap layer 650b may be provided between the dielectric layer 120 and the barrier layer 630 to cover lateral surfaces and a lower surface of the barrier layer 630. Like the first cap layer 650a, the second cap layer 650b may include a graphene-metal composite in which graphene and a metal are mixed with each other.
Referring to
The first cap layer 750a may cover an upper surface of the barrier layer 730. The first cap layer 750a may include a graphene-metal composite in which graphene and a metal are mixed with each other. The first cap layer 750a may be one of the cap layers 150, 250, and 350 described in the embodiments above. The second cap layer 750b may be provided on inner walls of the trench 120a. The second cap layer 750b may be provided between the dielectric layer 120 and the barrier layer 730 to cover lateral surfaces and a lower surface of the barrier layer 730. Like the first cap layer 750a, the second cap layer 750b may include a graphene-metal composite in which graphene and a metal are mixed with each other.
Referring to
The first cap layer 850a may cover an upper surface of the conductive line 840. The first cap layer 850a may include a graphene-metal composite in which graphene and a metal are mixed with each other. The second cap layer 850b may be provided on lateral surfaces of the conductive line 840. The second cap layer 850b may be provided between the barrier layer 830 and the conductive line 840 to cover the lateral surfaces of the conductive line 840. Like the first cap layer 850a, the second cap layer 850b may include a graphene-metal composite in which graphene and a metal are mixed with each other.
Referring to
The first cap layer 950a may cover an upper surface of the conductive line 940. The first cap layer 950a may include a graphene-metal composite in which graphene and a metal are mixed with each other. The second cap layer 950b may be provided on a lower surface of the conductive line 940. The second cap layer 950b may be provided between the barrier layer 930 and the conductive line 940 to cover the lower surface of the conductive line 940. Like the first cap layer, the second cap layer 950b may include a graphene-metal composite in which graphene and a metal are mixed with each other.
In each of the interconnect structures of the example embodiments described above, the cap layer formed on the conductive line includes a graphene-metal composite in which graphene having a resistance reducing effect and a metal having a reliability improving effect are mixed with each other, thereby improving reliability by reducing the resistance of the conductive line and improving the electromigration resistance of the conducive line. For example, the interconnect structures may be applied to BEOL structures or the like of electronic devices such as DRAM devices or logic devices.
Referring to
The device element 115 may include an electrode or another part of a circuit structure. The circuit structure may be a capacitor, a diode, a resistor, or a wire, but is not limited thereto. In some embodiments, a liner layer (not shown) may be between the conductive lines 440, 540, 640, 740, 840, and 940 and the dielectric layer 120 and/or device element 115. The substrate 105 may include Si, Ge, SiC, SiGe, SiGeC, a Ge alloy, GaAs, InAs, InP, or the like. However, this is merely an example, and the substrate may include various semiconductor materials other than the listed materials. Examples of the substrate 105 may include a silicon-on-insulator (SOI) substrate and a silicon germanium-on-insulator (SGOT) substrate.
In addition, the substrate 105 may include a non-doped semiconductor material or a doped semiconductor material. For example, as depicted in
Referring to
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of inventive concepts as defined by the following claims.
Number | Date | Country | Kind |
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10-2021-0104813 | Aug 2021 | KR | national |