JP4352080B2 - Wiring, electronic device, and method of manufacturing electronic device - Google Patents

Description

  The present invention relates to a wiring using a carbon nanotube, an electronic device, and a method for manufacturing the electronic device.

  As a wiring material for a semiconductor device such as a large-scale integrated circuit (LSI), carbon nanotubes have been proposed and developed instead of metal materials such as aluminum (Al) and copper (Cu) (for example, Patent Document 1). reference.). For example, in a multilayer wiring using an interlayer insulating film, a carbon nanotube is used as a wiring (plug) buried in a via. When carbon nanotubes are embedded in the vias, carbon nanotubes are deposited from the conductive film of the lower wiring to the height of the vias by, for example, plasma chemical vapor deposition (CVD). Alternatively, after carbon nanotubes are deposited beyond the via height, planarization is performed by chemical mechanical polishing (CMP).

Thereafter, a conductive film is deposited on the plug to form an upper wiring electrically connected to the lower wiring. In this case, the contact between the conductive film of the upper wiring and the carbon nanotube is limited to the upper end face. Carbon nanotubes have a hollow structure. Therefore, the contact area is reduced, the contact resistance between the carbon nanotube and the upper wiring is large, and it is difficult to obtain a good contact.
JP 2002-329723 A

  An object of the present invention is to provide a wiring, an electronic device, and an electronic device manufacturing method capable of reducing resistance.

  According to the first aspect of the present invention, (b) a wiring for electrically connecting the first conductive film and the second conductive film on the first conductive film, and (b) the first conductive film A plurality of first metal particles above, (c) a plurality of first carbon nanotubes having one end connected to the surface of the first conductive film via each of the plurality of first metal particles, and (d) a plurality of first A plurality of second metal particles on a side surface on the other end side of each carbon nanotube, and (e) one end connected to each surface of the plurality of first carbon nanotubes via each of the plurality of second metal particles, A wiring including a plurality of second carbon nanotubes connected to the second conductive film is provided.

    According to the second aspect of the present invention, (b) wiring that electrically connects the first conductive film and the second conductive film that are spaced apart from each other, and (b) the first and second conductive films. A plurality of first metal particles on each surface of the film facing each other, and (c) one end connected to each surface of the first and second conductive films via each of the plurality of first metal particles, A plurality of first carbon nanotubes extending in opposite directions so that at least some of them overlap each other in a direction orthogonal to the surfaces of the first and second conductive films, and (d) a plurality of carbon nanotubes on the side surface of the first carbon nanotube (E) a plurality of second carbon nanotubes having one end connected to each of the first carbon nanotubes extending in opposite directions to each other via each of the plurality of second metal particles, ) Multiple second carbon nanochus The Bed is provided wiring that a plurality of first carbon nanotube extending in opposite directions are electrically connected to each other.

  According to the third aspect of the present invention, (b) a wiring layer made of the first conductive film provided on the substrate, and (b) a plurality of first metal particles on the first conductive film, a plurality of A plurality of first carbon nanotubes having one end connected to the surface of the first conductive film through each of the first metal particles, a plurality of second metal particles on the other side surface of each of the plurality of first carbon nanotubes; A wiring including a plurality of second carbon nanotubes having one end connected to the surface of each of the plurality of first carbon nanotubes via each of the plurality of second metal particles; and (c) connected to each of the plurality of second carbon nanotubes. An electronic device is provided that includes a second conductive film that is an upper wiring layer of the first conductive film.

  According to the fourth aspect of the present invention, (b) a step of forming a first conductive film on a substrate, (b) a step of forming first metal particles on the surface of the first conductive film, and (c) A step of depositing a plurality of first carbon nanotubes so that one end thereof is connected to the respective surfaces of the plurality of first metal particles; and (d) a plurality of second metals on the other side of the plurality of first carbon nanotubes. Applying a particle; (e) depositing a plurality of second carbon nanotubes such that one end thereof is connected to the surface of each of the plurality of second metal particles; and (f) at least one of the plurality of second carbon nanotubes. Forming a second conductive film so as to be electrically connected to a part of the electronic device.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the highly reliable wiring, electronic device, and manufacturing method of an electronic device which can reduce resistance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  As shown in FIGS. 1 and 2, an electronic device such as a semiconductor device according to an embodiment of the present invention has a first conductive film (lower wiring layer) 12, an interlayer insulating film 14, a wiring on a base insulating film 10. (Plug) 24, second conductive film (upper wiring layer) 26, and the like. The electronic device also includes a substrate (not shown) on which transistors and the like are formed below the base insulating film 10. A first conductive film 12 that is a wiring layer provided on the base insulating film 10 and a second conductive film 26 that is a wiring layer provided on the interlayer insulating film 14 are electrically connected by a plug 24. The interlayer insulating film 14 has a through hole (via) 15 in which a plug 24 is disposed.

  The plug 24 has a plurality of first metal particles 16 on the first conductive film 12 and a plurality of conductive members (first conductive members) connected to the surface of the first conductive film 12 through the plurality of first metal particles 16. 1 carbon nanotube) 18, the plurality of second metal particles 20 on the side surfaces on the other end side of each of the plurality of conductive members 18, and the plurality of conductive members 18 via the plurality of second metal particles 20, respectively. A conductive member (second carbon nanotube) 22 having one end connected to the surface is included. The other end of the conductive member 18 and a part of the conductive member 22 are in contact with the second conductive film 26 provided on the interlayer insulating film 14, and the first and second conductive members separated from each other are the conductive member 18. It is electrically connected via.

For example, carbon thin wires such as carbon nanotubes are used as the conductive members 18 and 22. As shown in FIG. 3, the conductive member 22 extends from the second metal particles 20 disposed on the side surface of the conductive member 18 in the diameter direction of the conductive member 18. The average diameter Da of the conductive member 18 is in the range of about 2 nm to about 10 nm, desirably about 4 nm to about 6 nm. The average diameter Db of the conductive member 22 is about 1 nm to about 5 nm, desirably about 2 nm to about 4 nm, and the length Lb is about 1 nm or more. In order to reduce the resistance, the conductive member 18 preferably has a surface density in the range of about 8 × 10 ¹¹ cm ⁻² to about 1.2 × 10 ¹² cm ⁻² .

  The first and second metal particles 16 and 20 act as a catalyst metal for carbon nanotube growth. As the first and second metal particles 16 and 20, metal particles such as a metal such as cobalt (Co), nickel (Ni), iron (Fe), or an alloy mainly composed of Co, Ni, Fe, or the like are used. . It is desirable to use different metal materials for the first and second metal particles 16 and 22. For example, it is desirable to use Co as the first metal particles 16 and Ni or Fe as the second metal particles 20.

  The diameter of the carbon nanotube that is the conductive member 18 is controlled by the diameter of the first metal particle 16. Therefore, the average particle diameter of the first metal particles 16 is in the range of about 2 nm to about 10 nm, desirably about 4 nm to about 6 nm.

  Similarly, the diameter of the carbon nanotube that is the conductive member 22 is controlled by the diameter of the second metal particle 20. Accordingly, the average particle size of the second metal particles 20 is in the range of about 1 nm to about 5 nm, desirably about 2 nm to about 4 nm.

Further, as the first conductive film 12 and the second conductive film 26, a metal such as Cu, Al, tungsten (W) is used. As the base insulating film 10 and the interlayer insulating film 14, a silicon oxide (SiO ₂ ) film, a silicon nitride (Si ₃ N ₄ ) film, a low dielectric constant (low-k) insulating film, or the like is used. As a material of the low-k insulating film, an inorganic material such as carbon-added silicon oxide (SiOC) or inorganic spin-on-glass (SOG), or an organic material such as organic SOG can be used. Further, a laminated film such as an inorganic material film and an organic material film may be used as the low-k insulating film.

  As shown in FIGS. 2 and 3, a large number of conductive members 22 provided on the side surface of the conductive member 18 on the second conductive film 26 side can be brought into contact with the second conductive film 26 together with the conductive member 18. Therefore, the contact resistance between the plug 24 and the second conductive film 26 is reduced by increasing the contact area. Thus, by using the wiring according to the embodiment of the present invention, the wiring resistance can be reduced, and a high-performance semiconductor device can be realized.

It is desirable to use a plasma CVD method for forming the carbon nanotubes used for the conductive members 18 and 22. FIG. 4 shows a surface wave plasma CVD apparatus as an example. The microwave introduced from the microwave waveguide 60 is introduced into the reaction chamber via the slit antenna 62 and the quartz window 64 for microwave introduction. A source gas containing carbon, such as methane (CH ₄ ) gas and hydrogen (H ₂ ) gas, is introduced into the reaction chamber from the gas inlet 70. The reaction chamber is maintained at a predetermined pressure by a gas flow rate and a gas pressure regulator (not shown) installed at the gas exhaust port 68. The substrate 2 is placed on a heater built-in susceptor 66 and maintained at a predetermined temperature. For example, carbon nanotube growth conditions are CH ₄ gas of about 10 sccm, H ₂ gas of about 90 sccm, reaction chamber pressure of about 900 Pa, substrate temperature of about 600 ° C., and microwave power of about 1 kW.

  Next, a method for manufacturing a semiconductor device according to an embodiment of the present invention will be described with reference to process cross-sectional views shown in FIGS.

(A) First, a circuit pattern such as a transistor is formed on a substrate such as a semiconductor. A base insulating film 10, a first conductive film 12, and an insulating film (interlayer insulating film) 14 are sequentially deposited on the formed circuit pattern by CVD, vapor deposition, or the like. As shown in FIG. 5, vias 15 are formed in the interlayer insulating film 14 by photolithography, dry etching, or the like. Metal particles such as Co are deposited on the surface of the first conductive film 12 exposed in the via 15 to form the first metal particles 16. The average diameter of the first metal particles 16 is, for example, about 5 nm, and the deposition surface density is about 1 × 10 ¹² cm ⁻² .

  (B) As shown in FIG. 6, the carbon nanotubes are grown on the surface of the first metal particles 16 in the via 15 to the level of the surface of the interlayer insulating film 14 by surface wave plasma CVD or the like to form the conductive member 18. To do. The average diameter of the conductive member 18 is about 5 nm corresponding to the average diameter of the first metal particles 16.

  (C) As shown in FIG. 7, metal particles such as Ni are applied to the side surface of the conductive member 18 to form second metal particles 20. The average diameter of the second metal particles 20 is, for example, about 2 to about 3 nm. The second metal particles 20 cannot pass deeply in the bottom direction of the via 15 through the plurality of conductive members 18 during application. Therefore, the second metal particles 20 are applied at a higher density on the tip of the conductive member 18 than on the bottom side of the via 15.

  (D) As shown in FIG. 8, the carbon nanotube is grown on the surface of the second metal particle 20 by surface wave plasma CVD or the like to form the conductive member 22. The average diameter of the conductive member 22 is about 2 to about 3 nm corresponding to the average diameter of the second metal particles 20. The average length of the conductive member 22 is about 10 nm. In order to prevent further growth of carbon nanotubes from the tip of the conductive member 18, the carbon nanotube growth conditions of the conductive member 22 may be performed under conditions different from the carbon nanotube growth conditions of the conductive member 18.

  (E) As shown in FIG. 9, a second conductive film 26 as an upper wiring layer is formed on the surface of the interlayer insulating film 14 and the plug 24 by sputtering, photolithography, dry etching, or the like. Further, a required wiring layer is formed on the second conductive film 26, and a semiconductor device is manufactured.

  Here, the diameter and deposition surface density of the carbon nanotubes deposited as the conductive member 18 are controlled by the first metal particles 16 as the base. For example, the first metal particles 16 are formed by depositing metal particles such as Co having an average particle diameter of about 5 nm at a desired surface density by ablation or the like. Alternatively, the first metal particles 16 may be formed by aggregating a deposited metal thin film such as Co at a predetermined temperature.

  According to the method of manufacturing a semiconductor device according to the embodiment of the present invention, a large number of conductive members 22 are formed on the side surface of the conductive member 18 on the second conductive film 26 side. Therefore, the second conductive film 26 contacts not only the conductive member 18 but also a large number of conductive members 22. Therefore, the contact resistance between the plug 24 and the second conductive film 26 is reduced by increasing the contact area. As described above, the manufacturing method of the semiconductor device according to the embodiment of the present invention can reduce the wiring resistance and realize a high-performance semiconductor device.

(Other embodiments)
Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment of the present invention, the carbon nanotube as the conductive member 18 is used for the plug 24 of the vertical wiring that connects the lower and upper wiring layers. However, the carbon nanotube is not limited to the vertical wiring for connecting the wiring layers. For example, it can be used for a lateral wiring parallel to the surface of the base insulating film.

  For example, as shown in FIG. 10, first metal particles 16a and 16b are deposited on the side surfaces of conductive films 12a and 12b formed on the surface of the base insulating film 10 so as to face each other. Conductive members 18a and 18b are grown on the surfaces of the first metal particles 16a and 16b so as to at least partially overlap in the direction substantially parallel to the surface of the base insulating film 10. The second metal particles 20a and 20b are applied to the side surfaces of the conductive members 18a and 18b, respectively. Conductive members 22a and 22b are grown on the surfaces of the second metal particles 20a and 20b, respectively. Here, it is possible to reduce the wiring resistance between the conductive films 12a and 12b by growing the conductive members 22a and 22b so as to be in contact with each other.

  In the embodiments of the present invention, a method for manufacturing a semiconductor device has been described. However, the present invention is not limited to a semiconductor device, and is not limited to a semiconductor device. It can be easily understood from the above description that the present invention can also be applied to a method of manufacturing an electronic device such as an element.

  As described above, the present invention naturally includes various embodiments that are not described herein. Accordingly, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a plane schematic diagram showing an example of wiring concerning an embodiment of the invention. It is the schematic which shows the AA cross section of the wiring shown in FIG. It is the schematic which shows an example of the wiring structure used for description of embodiment of this invention. It is the schematic which shows an example of the apparatus used for the growth of the electrically-conductive member of the wiring which concerns on embodiment of this invention. It is process sectional drawing (the 1) which shows an example of the manufacturing method of the semiconductor device which concerns on embodiment of this invention. It is process sectional drawing (the 2) which shows an example of the manufacturing method of the semiconductor device which concerns on embodiment of this invention. It is process sectional drawing (the 3) which shows an example of the manufacturing method of the semiconductor device which concerns on embodiment of this invention. It is process sectional drawing (the 4) which shows an example of the manufacturing method of the semiconductor device which concerns on embodiment of this invention. It is process sectional drawing (the 5) which shows an example of the manufacturing method of the semiconductor device which concerns on embodiment of this invention. It is a section schematic diagram showing an example of wiring concerning other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Base insulating film 12 ... 1st electrically conductive film 14 ... Interlayer insulating film 15 ... Through-hole (via)
16 ... 1st metal particle 18 ... Conductive member (1st carbon nanotube)
20 ... 2nd metal particle 22 ... Conductive member (2nd carbon nanotube)
24 ... Wiring (plug)
26. Second conductive film

Claims (9)

A wiring for electrically connecting the first conductive film and the second conductive film on the first conductive film;
A plurality of first metal particles on the first conductive film;
A plurality of first carbon nanotubes connected at one end to the surface of the first conductive film via each of the plurality of first metal particles;
A plurality of second metal particles on a side surface on the other end side of each of the plurality of first carbon nanotubes;
A plurality of second carbon nanotubes having one end connected to the surface of each of the plurality of first carbon nanotubes via each of the plurality of second metal particles and each connected to the second conductive film. And wiring.   The wiring according to claim 1, wherein a diameter of the second carbon nanotube is smaller than a diameter of the first carbon nanotube.   The wiring according to claim 1, wherein the first and second metal particles include at least one of iron, nickel, and cobalt.   The wiring according to claim 1, wherein the first and second metal particles are different metal materials. A wiring for electrically connecting the first conductive film and the second conductive film which are arranged apart from each other;
A plurality of first metal particles on opposite surfaces of the first and second conductive films;
One end is connected to the surface of each of the first and second conductive films via each of the plurality of first metal particles, and at least one of the first and second conductive films is perpendicular to the surfaces of the first and second conductive films. A plurality of first carbon nanotubes extending in opposite directions so that the portions overlap,
A plurality of second metal particles on a side surface of the first carbon nanotube;
A plurality of second carbon nanotubes having one end connected to each of the first carbon nanotubes extending in opposite directions to each other via each of the plurality of second metal particles, and the plurality of second carbon nanotubes, The wiring, wherein the plurality of first carbon nanotubes extending in opposite directions are electrically connected to each other. A wiring layer made of a first conductive film provided on the substrate;
A plurality of first metal particles on the first conductive film, a plurality of first carbon nanotubes having one end connected to the surface of the first conductive film via each of the plurality of first metal particles, A plurality of second metal particles on the side surface on the other end side of each carbon nanotube, and a plurality of one ends connected to the respective surfaces of the plurality of first carbon nanotubes via the plurality of second metal particles, respectively. Wiring containing second carbon nanotubes;
An electronic device comprising: a second conductive film connected to each of the plurality of second carbon nanotubes and serving as an upper wiring layer of the first conductive film.     7. The method according to claim 6, further comprising an interlayer insulating film formed between the first and second conductive films, wherein the wiring is disposed in a through hole provided in the interlayer insulating film. Electronic devices. Forming a first conductive film on the substrate;
Forming a plurality of first metal particles on the surface of the first conductive film;
Depositing a plurality of first carbon nanotubes such that one end thereof is connected to the surface of each of the plurality of first metal particles;
Applying a plurality of second metal particles to the other side surface of the plurality of first carbon nanotubes;
Depositing a plurality of second carbon nanotubes such that one end thereof is connected to a surface of each of the plurality of second metal particles;
Forming a second conductive film so as to be electrically connected to at least a part of the plurality of second carbon nanotubes.   9. The method of manufacturing an electronic device according to claim 8, wherein the first and second carbon nanotubes are deposited using a gas containing carbon.

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