JP5920808B2 - Method for forming wiring pattern - Google Patents

Description

  The present invention relates to a technique for forming a wiring pattern having a graphite film including a graphene structure with good film quality.

  Conventionally, copper has been used as a wiring material for integrated circuits. Recently, the use of graphene, graphite (multilayer graphene), or the like, which is a carbon material, has been proposed as a wiring material that replaces copper. Such integrated circuit wiring made of graphite or the like can suppress the rise in resistivity caused by miniaturization compared to copper, thus eliminating thermal problems and wiring delay (processing speed reduction) problems. There is expected.

  As a method for forming a graphite film serving as a wiring material on a substrate of an integrated circuit, for example, in Patent Document 1, a catalyst layer made of nickel, cobalt, iron or the like is deposited on a substrate so that the crystal orientation is aligned. In addition, by performing high-temperature CVD (chemical vapor deposition) treatment at 600 ° C. while supplying carbon atoms, graphene on the catalyst layer is similarly controlled to obtain desired electrical conductivity A method of forming a sheet is disclosed.

  Further, for example, Patent Document 2 discloses a technique of depositing a catalyst layer made of a metal such as nickel, cobalt, iron, platinum or the like on a substrate and forming a graphene layer on the catalyst layer. It is also disclosed that the layer may be composed of a combination of multiple metals.

  Further, for example, Non-Patent Document 2 relates to a method of forming a carbon nanocoil instead of a graphite film, and a catalyst obtained by atomizing two kinds of substances, a substance that easily diffuses carbon and a substance that hardly diffuses. Thus, a method for forming high-quality carbon nanocoils by treatment at a low temperature (450 ° C.) is disclosed.

  In Non-Patent Document 2, more specifically, amorphous carbon is deposited on a substrate, a catalyst layer made of a nickel thin film is placed on the substrate, and heat treatment is performed, whereby the catalyst is produced using the amorphous carbon as a carbon source. A technique for forming a graphene layer on the layer is disclosed.

JP 2009-164432 A US Patent Publication No. 2009/0110627

Yutaka Ishikawa, “Low-temperature synthesis and wire diameter control of carbon nanocoils using copper-nickel alloy thin film as catalyst” (Surface Technology Volume 59, No. 5, pages 346-348, issued on May 1, 2008) Maxwell Zheng et al. "Metal-catalyzed crystallization of amorphous carbon to graphene" (APPLIED PHYSICS LETTERS 96, 063110 (2010))

  However, the above conventional technique has the following problems. That is, in the graphite film forming technique of Patent Document 1, the catalyst is a single raw material. For example, if nickel, the amount of carbon entering and diffusing into the catalyst layer is large, an excessive carbon source is deposited. The formed graphite film often has a defect structure.

  In addition, when the catalyst metal is copper, there is a problem that, on the contrary, only a surface reaction occurs because the carbon intrusion amount and diffusion amount are small, and a single-layer graphene film is formed, which is not suitable as a wiring material. .

  Further, Patent Document 2 discloses that a plurality of metal elements are used in combination as a catalyst layer, but there is no disclosure or suggestion about a specific combination, and the catalyst layer is configured. No mention is made of the diffusion of carbon to metal elements, and the problem of the amount of carbon diffusion in the catalyst layer cannot be solved as in Patent Document 1. Therefore, there is a problem that the graphite film has a defect structure or a single-layer graphene film is formed, which is not suitable as a wiring material.

  Furthermore, since it is difficult for a graphite film to be formed at a low temperature such as 450 ° C., a graphite film is preferably formed at a temperature of about 600 to 1000 ° C. However, if the treatment is performed at a high temperature, the catalyst layer is aggregated by the heat, and the catalyst that has been formed into particles is scattered on the substrate surface. In either of the above-mentioned Patent Documents 1 and 2, there is no disclosure or suggestion about the cohesiveness at the time of heating in the metal serving as the catalyst or a combination of a plurality of metals, and this cohesiveness problem cannot be solved. Therefore, even if a graphite film can be formed by the techniques disclosed in Patent Documents 1 and 2, there is a possibility that sufficient electrical characteristics and the like as a wiring material cannot be exhibited.

  Further, the technique of Non-Patent Document 1 has a problem that since a helical carbon nanocoil is formed, it is not suitable as a wiring material for which a planar film is required.

  Furthermore, in the techniques described in the above patent documents and non-patent documents, it is not easy to form a highly oriented graphite film. In Patent Document 1, the orientation of the graphite film is enhanced by the catalyst layer in which the crystal direction is controlled. For this purpose, it is necessary to control the crystal direction of the catalyst layer.

  Further, in order to form a wiring pattern with a graphite film and use it as an electronic device, conventionally, a graphite film is formed using a patterned metal thin film as a catalyst, and then “transferred” onto a substrate. However, there is a problem that the process of “transferring” the graphite film to another substrate has a high risk and the subsequent processes cannot be performed continuously.

  Furthermore, in the method for forming a graphite film disclosed in the above patent document and non-patent document, the graphite film is formed on the catalyst layer. Therefore, the height of the wiring layer is increased by the amount of the catalyst layer, and there is a problem that it is difficult to obtain a wiring pattern having a high aspect ratio (ratio h / w of height h to width w). Further, the catalyst layer is not necessarily an element necessary for the wiring. Without the catalyst layer, the catalyst layer can be composed of only graphite having a long mean free path of electrons, and thereby a low resistance wiring can be obtained.

  Therefore, in order to solve the above-mentioned problems, the present invention suppresses the aggregation of the catalyst layer and controls the carbon diffusivity, thereby forming a graphite film having a graphene structure that can form a defect-free graphite film. It is an object to provide a method for forming a wiring pattern using a film.

In order to solve the above problems, the present invention firstly
Forming a catalyst layer on a base material, comprising a first component that diffuses carbon and a second component that suppresses aggregation of the first component and / or diffusion of carbon to the first component Process,
A graphite film forming step of forming a graphite film including a graphene structure on a surface of the catalyst layer opposite to the base;
Having
A wiring pattern forming method (first method) is provided.

In addition, the present invention secondly,
A carbon compound layer forming step of forming a carbon compound layer composed of a carbon compound on the substrate;
A first component that diffuses carbon and a second component that suppresses aggregation of the first component and / or diffusion of carbon to the first component on a surface of the carbon compound layer opposite to the base. A catalyst layer forming step of forming a catalyst layer containing components,
Heating the substrate having the carbon compound layer and the catalyst layer, and forming a graphite film including a graphene structure from the carbon compound layer; and
Having
A wiring pattern forming method (second method) is provided.

  In the first method, a graphite film containing a graphene structure is formed on the surface (exposed surface) of the catalyst layer opposite to the base material. In the second method, the catalyst layer After forming a laminate in which a carbon source (carbon compound layer) is disposed between the layer and the substrate, a graphite film including a graphene structure is formed from the carbon source.

  According to the present invention having such a configuration, the second component constituting the catalyst layer has a function of suppressing aggregation of the first component and / or suppressing diffusion of carbon to the first component. By suppressing the aggregation of carbon and controlling the diffusibility of carbon, it is possible to more reliably form a wiring pattern composed of a graphite film including a graphene structure having no defect.

  Here, the “graphite film including a graphene structure” in the present invention only needs to include a graphene structure having a thickness of, for example, a carbon atom level. For example, a graphite film composed of a single graphene structure and a plurality of layers of graphene It is a concept including a graphite film composed of a structure (laminate).

  Therefore, the thickness of the “graphite film including a graphene structure” in the present invention may be, for example, 0.3 nm to 20 nm, but can be appropriately selected according to the type of the substrate described later. For example, in a semiconductor device, when the wiring pattern width is about 10 nm, the thickness of the aspect ratio is not too high so that the electric capacitance value of the “graphene film including a graphene structure” does not become too high and the processing speed becomes slow. For example, the thickness may be 10 nm to 20 nm.

In the present invention, the (metal) element of the first component and the second component can be selected by paying attention to, for example, the carbon diffusion coefficient, and the carbon diffusion coefficient D ₁ of the first component and the carbon diffusion of the second component. and the coefficient _{D 2} is _relation: D 1> satisfy the _{D 2,} are preferred. Carbon diffusion coefficients are collected as experimental data as basic physical properties of materials such as metals. For example, the Japan Institute of Metals, 4th edition, Metal Data Book (issued February 29, 2004) ) Etc.

  In the present invention, the catalyst layer includes the first layer containing the first component and the second component even if the catalyst layer is composed of an alloy layer containing the first component and the second component. You may be comprised with the laminated body of the 2nd layer. For example, by appropriately adjusting the composition of the first component and the second component in the alloy layer, the thickness of the first layer and the second layer in the laminate, etc., the effect of the present invention is obtained in both the alloy layer and the laminate be able to. In the latter case, a “graphite film including a graphene structure” may be formed on either side of the first layer and the second layer, and details will be described later.

  The first component and the second component are nickel, cobalt, iron, tungsten, titanium, tantalum, molybdenum, niobium, rhenium, copper, ruthenium, platinum, gold, boron, phosphorus, nitrogen, oxygen, sulfur, respectively. And at least one selected from the group consisting of carbon.

The carbon diffusion coefficient D (m ² / s) of typical (metal) elements among these is as follows.
Nickel: 1.2 × 10 ⁻⁵
Cobalt: 7.6 × 10 ⁻⁵
Iron (α-Fe): 2.3 × 10 ⁻⁵
Tungsten: 9.2 × 10 ⁻⁷
Titanium (α-Ti): 7.9 × 10 ⁻⁶
Titanium (β-Ti): 3.9 × 10 ⁻⁷
Tantalum: 6.4 × 10 ⁻⁷
Molybdenum: 1.0 × 10 ⁻⁶
Niobium: 3.3 × 10 ⁻⁶

  Further, for example, the first component may be at least one selected from the group consisting of nickel, cobalt and iron, and the second component is tungsten, titanium, tantalum, molybdenum, niobium, rhenium, copper, ruthenium. , Platinum, gold, boron, phosphorus, nitrogen, oxygen, sulfur and carbon.

The catalyst layer is at least from the group consisting of nickel, cobalt, iron, tungsten, titanium, tantalum, molybdenum, niobium, rhenium, copper, ruthenium, platinum, gold, boron, phosphorus, nitrogen, oxygen, sulfur and carbon. It is preferable to contain two kinds of elements.
More specifically, the catalyst layer includes, for example, nickel-boron, nickel-phosphorus, nickel-tungsten-phosphorus, nickel-tungsten-boron, cobalt-boron, cobalt-phosphorus, cobalt-tungsten-phosphorus, cobalt-tungsten. -It is preferable that it is comprised with boron or copper-tungsten.

In the present invention, as the base material, various conventionally known materials can be used. For example, silicon dioxide (SiO ₂ ), various glasses, insulators such as silicon (Si), copper (Cu), etc. Examples thereof include metals, semiconductors such as SiC, and sapphire. In addition, for example, Si ₃ N ₄ (silicon nitride), SiOF (fluorine-added silicon oxide film), SiON (nitrogen-added silicon oxide film), SiOC (SiO ₂ doped with carbon), BN, HSQ (Fluorine-added silicon oxide film: interlayer insulating material), xerogel, airgel, perylene, polynaphthalene, amorphous carbon / fluoride (a-CF), MSQ (organic SOG: low dielectric constant interlayer insulating material for VLSI), SiCOH (SiO ₂ containing methyl, such as black diamond) is included. However, an insulator such as silicon dioxide and a metal such as copper are preferred from the viewpoint that a wiring pattern having a multilayer structure can be formed and a high temperature is not required in the manufacturing process.

  The carbon compound in the second method is preferably carbon such as amorphous carbon or an organic compound such as an organic silane compound.

  The wiring pattern forming method of the present invention as described above can be suitably applied to a semiconductor device manufacturing method. Therefore, the present invention also provides a semiconductor device manufacturing method including the wiring pattern forming method.

  According to the present invention as described above, a graphite film including a graphene structure having no defects can be obtained by suppressing the aggregation of the catalyst layer and controlling the diffusibility of carbon without using the conventional “transfer” step. The configured wiring pattern can be more reliably formed. In other words, the formation of a wiring pattern consisting of a “graphite-structured graphite film” with high quality and high crystal orientation by preventing the catalyst layer from agglomerating at high temperatures and suitably adjusting the carbon diffusivity of the catalyst layer. can do. Therefore, a wiring pattern or a semiconductor device having excellent electrical characteristics, mechanical strength, and the like can be manufactured.

  In particular, according to the second method, the heat treatment is performed by placing a carbon source under the catalyst layer in which the carbon diffusibility and the cohesiveness at high temperature are controlled as described above. A graphite film can be formed thereunder. After the formation of the graphite film, the catalyst layer on the graphite film can be easily removed by a conventionally known method such as etching. Therefore, the aspect of the wiring is suitably adjusted, and a high-quality wiring material can be obtained. Can do.

The figure for demonstrating an example of the formation method of the wiring pattern of Embodiment 1 of this invention Raman spectrum chart for comparing the quality of graphite films formed according to the thickness of the catalyst layer Conceptual diagram showing an example of catalyst layer formation by sputtering and electroless plating The figure for demonstrating an example of the formation method of the wiring pattern of Embodiment 2 of this invention The figure which shows the transmission electron micrograph of the board | substrate which formed the graphite film by the method of Example 6 of Embodiment 2 (before removing a catalyst layer by an etching)

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to these embodiment at all, and can be implemented with various aspects in the range which does not deviate from the summary.

Embodiment 1
This embodiment
Forming a catalyst layer on a base material, comprising a first component that diffuses carbon and a second component that suppresses aggregation of the first component and / or diffusion of carbon to the first component Process,
A graphite film forming step of forming a graphite film including a graphene structure on a surface of the catalyst layer opposite to the base;
Having
1 is an embodiment of a method for forming a wiring pattern (first method).

  More specifically, in the present embodiment, for example, a first component composed of one or more of nickel, cobalt, iron and the like, and tungsten, titanium, tantalum, molybdenum, niobium, rhenium, copper, ruthenium, platinum Utilizing a catalyst containing a second component composed of one or more of gold, boron, phosphorus, nitrogen, oxygen, sulfur, carbon, etc., or a layer mainly composed of the first component and a second component In this method, a graphite film is formed using a catalyst layer in which a main layer is laminated, and a wiring pattern is formed from the graphite film. In particular, a method for forming a graphite film on the upper layer of the catalyst layer is disclosed.

  An example of a method for forming a wiring pattern according to this embodiment will be described with reference to FIG. As shown in FIG. 1A, after an insulating film such as a Si oxide film is formed on the substrate by, for example, a vapor deposition method, as shown in FIG. A catalyst containing the component and the second component is formed on the Si oxide film of the substrate. Then, as shown in FIG. 1C, a graphite film is formed on the substrate on which the catalyst is formed by using a vapor phase growth method such as CVD.

  Then, a wiring resist pattern is formed on the graphite film thus formed, and a portion other than the wiring is selectively removed by dry etching or the like, thereby forming a wiring pattern made of the graphite film.

Alternatively, as shown in FIG. 1B, a wiring pattern may be formed on the catalyst layer after the catalyst layer is formed on the substrate. In this case, in the step of forming the graphite film of FIG. 1 (c), graphite is not formed in the portion where there is no catalyst layer, while graphite is formed only on the patterned catalyst layer.
Hereinafter, each step in the wiring pattern forming method of this embodiment will be described in detail.

(1) Catalyst layer The composition of the catalyst layer of this embodiment will be described. The “catalyst layer” includes a first component that easily diffuses carbon, and a second component having a substance that suppresses aggregation of the first component or / and a substance that suppresses diffusion of carbon to the first component. . Alternatively, the “catalyst layer” mainly includes a layer having a first component that easily diffuses carbon, and a substance that mainly suppresses aggregation of the first component or / and a substance that suppresses diffusion of carbon to the first component. And a layer containing a second component.

  In this embodiment, examples of the material that can be used as the first component include nickel, cobalt, and iron. When used as the first component, these can be used alone or in combination of two or more substances.

  In addition, as materials that can be used as the second component, for example, tungsten, titanium, tantalum, molybdenum, niobium, rhenium and copper, which are high melting point metals, ruthenium, platinum, gold, which are noble metals, and boron used as a dopant for semiconductors, Examples include phosphorus, nitrogen, oxygen, sulfur, and carbon. These substances can be used alone or in combination of two or more substances.

  Regarding the second component, the substance that suppresses the aggregation of the first component and the substance that suppresses the diffusion of carbon into the first component may be common (for example, the first component is cobalt and the second component Is tungsten). On the other hand, the second component has no action of suppressing aggregation of the first component, but, for example, boron (B) can be used as a substance that suppresses diffusion of carbon into the first component. The second component boron (B) can suppress carbon diffusion to nickel by doping the first component nickel (Ni), and the resulting graphite film is doped with boron atoms. This is preferable because electrical characteristics are improved. In addition, the recrystallization temperature of the catalyst layer may be lowered by doping boron into nickel and aggregation may easily occur. In this case, if the substrate is made of Cu, for example, aggregation can be effectively suppressed. it can.

  Further, the composition ratio of the first component and the second component is a design matter and is not particularly limited, but may be designed in consideration of the following factors. That is, as the ratio of the first component increases, the thickness of the deposited graphite film increases. On the other hand, as the ratio of the second component is increased, the aggregation of the catalyst layer that occurs during the graphite film forming process at a higher temperature is less likely to occur. Therefore, for example, a composition ratio that can withstand a processing temperature at which the film quality of graphite is suitable (aggregation can be suppressed) can be appropriately selected. Alternatively, the catalyst phase may be a catalyst layer made of a gradient material whose composition changes gradually.

  Moreover, when a catalyst layer is comprised with the alloy layer containing a 1st component and a 2nd component, based on the alloy phase diagram containing a 1st component and a 2nd component, you may determine both composition ratios . From the viewpoint that the effects of the first component and the second component can be more reliably brought out without forming a stable compound, for example, in the case of a nickel-boron alloy, the composition ratio of boron is more than 0% by mass. It may be 17% by mass or less, and in the case of a copper-tungsten alloy, the composition ratio of tungsten may be more than 0% by mass and about 71% by mass or less. The upper limit of the composition ratio of tungsten may be about 55% by mass from the viewpoint of not excessively increasing the resistance of the copper-tungsten alloy.

  In addition, when the second component contains a typical element, the composition ratio of the first component and the second component (typical element) can be appropriately selected, but the amount of the second component is from the viewpoint of suppressing aggregation of the catalyst layer. 5 mass% or more is preferable, More preferably, it is 8 mass% or more.

  In addition, as typical elements instead of B, typical elements such as phosphorus (P), nitrogen (N), oxygen (O), sulfur (S), and carbon (C) may be used. In particular, when boron or phosphorus is used as the second component, these may enter the formed graphite film. Since boron (group 3) and phosphorus (group 5) act as a source of holes and electrons, that is, as a dopant in a semiconductor, such a graphite film is suitable for a low-resistance wiring layer.

Here, for example, if a copper wiring in an integrated circuit is used as a base material, the present invention can be applied to a so-called damascene process. That is, after forming a copper wiring composed of a copper electroplating layer and then forming a catalyst layer in the present invention (for example, nickel-boron or cobalt-tungsten-phosphorus) thereon, a graphite film containing a graphene structure thereon Can be formed. In particular, when the catalyst layer is nickel-boron, cobalt-tungsten-phosphorus, or the like, boron or phosphorus is doped into the graphite film, and the electrical characteristics are improved, which is preferable. In the damascene process, the formation of nickel-boron or cobalt-tungsten-phosphorus on the copper wiring is called a metal cap.
Here, copper is attracting attention as a wiring material because its wiring resistance is lower than that of aluminum. However, copper on the surface of the wiring moves due to electromigration when a current is passed, causing voids (holes) in the wiring and breaking. There was a problem that made it easier. Also, copper easily penetrates into silicon (migration), which may cause a short circuit of wiring. On the other hand, a wiring structure has been proposed in which the copper wiring surface is stabilized by being covered with a thin cobalt alloy film or the like called a “metal cap” to improve the reliability of the copper wiring. The present invention can also be applied to such a wiring structure. For example, the cobalt-tungsten-phosphorus catalyst layer exhibits a function as a catalyst and also has a function as a metal cap.

  For the composition of other catalyst layers, for example, nickel-tungsten-phosphorus, nickel-tungsten-boron, cobalt-tungsten-phosphorus, cobalt-tungsten-boron, cobalt-tungsten-phosphorus-boron, copper-tungsten, etc. are also effective. As a suitable catalyst.

  Further, the thickness of the catalyst layer can be appropriately selected according to the design of the wiring pattern or the like actually made of a graphite film, and for example, a thickness of about 1 nm to 500 nm is preferable. Further, when the catalyst layer has a laminate of the first component and the second component, each layer is appropriately adjusted within the range of 1 nm to 499 nm so that the entire laminate is in the range of 2 nm to 500 nm. And good.

(2) Catalyst Layer Formation Step Next, an example of a method for forming the catalyst layer will be described in detail. In this embodiment, a catalyst is formed on a substrate. Examples of the base material include a semiconductor substrate, and a metal substrate, a glass epoxy substrate, a silicon substrate, and the like are preferable. “Forming on a substrate” includes both the case of forming directly on a substrate and the case of forming a catalyst on silicon oxide by coating a silicon oxide film on the surface of the substrate. The case where it is formed on various elements and wirings also corresponds to the case where it is formed on a substrate.

  As for the method of forming the catalyst layer having the above composition, for example, spin coating, dipping, brush coating, spray coating, electrostatic coating, electrodeposition coating and other coating methods, immersion plating, electroless plating, and other wet film formation Methods, chemical vapor deposition methods such as thermal CVD, plasma CVD, and laser CVD, vapor deposition methods such as vacuum deposition, sputtering, and ion plating, and thermal spraying, among others, wet film formation such as electroless plating. The method is preferable because it is easy to form a uniform thin film on the surface of a fine pattern, and the manufacturing cost can be relatively suppressed. In the case of sputtering, preferably, the sputtering gas is argon, the pressure is 1 mPa, and the DC power is 90 W.

  Further, when the catalyst layer is formed by electroless plating, it is possible to attach a Pd film as an underlayer that acts as a catalyst when depositing the catalyst layer on the substrate. The Pd film can be deposited on the substrate by physical vapor deposition, application of a solution containing fine Pd particles, or organic silane molecules as a bonding layer with the substrate, and precipitation from a Pd chloride solution. It is also possible to employ a method of attaching Pd.

  Moreover, in order to improve the adhesiveness of the catalyst layer with respect to a board | substrate, you may provide the intermediate | middle layer for improving adhesiveness on a board | substrate. For example, a thin film of titanium, tantalum, titanium nitride, tantalum nitride, or the like can be given.

(3) Graphite film forming step A graphite film is formed on the surface of the catalyst layer formed on the substrate as described above. For example, a graphite film can be formed by performing a thermal CVD process for supplying an alcohol vapor (carbon source) such as ethanol to the substrate on which the catalyst layer is formed. In addition, although the heating temperature in a thermal CVD process is 600 degreeC in a suitable example, it can set suitably in the range of 350 to 1000 degreeC, for example.
Examples of the alcohol as the carbon source include methanol, ethanol and butanol. Examples of the carbon source include methane (CH ₄ ), acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), and ethane (C ₂ H ₆ ), which are one kind of pure gas or a mixture of two or more kinds. A gas or a gas containing a benzene ring can also be used. Carbon dioxide (CO ₂ ) and carbon monoxide (CO) can also be used. In that case, a plasma CVD apparatus is preferably used. Further, when the film is formed by a wet method, PMMA or the like can be used as a carbon source.

  As another method for forming a graphite film, a carbon source such as amorphous carbon is deposited on the catalyst layer formed on the substrate instead of performing the thermal CVD process. The deposition method includes vapor deposition, dipping, spin coating, spray coating, and the like. Then, the substrate is heat-treated at, for example, 600 ° C. to form a graphite film on the catalyst.

  Alternatively, by appropriately selecting the heating temperature and the composition of the first component and the second component, the carbon diffused in the catalyst layer is deposited under the catalyst layer, and the catalyst layer and the substrate (the upper Si oxide film) A method of forming a graphite film during the period is also mentioned.

  Alternatively, before depositing the catalyst layer on the substrate, a carbon compound layer made of, for example, an organosilane molecule is deposited on the substrate by vapor deposition, dipping, spin coating, spray coating, or the like. Subsequently, the catalyst layer containing the first component and the second component of the present invention is formed on the substrate / carbon layer as described above. A carbon layer such as amorphous carbon is deposited on the catalyst by vapor deposition, dipping, spin coating, spray coating, or the like. When this is heated, the catalyst can take in a sufficient amount of carbon necessary to form a graphite film from above and below.

  Then, from the catalyst layer in which sufficient carbon is diffused inside, carbon is deposited on and / or below the catalyst layer, and a graphite film can be formed on or below the catalyst layer. In this case, for example, by removing the graphite film and the catalyst layer formed thereon, only the graphite film on the substrate may be used for forming the next wiring pattern.

  The film thickness (including the thickness of the catalyst layer) of the graphite film thus formed (when the graphite film is formed above and below the catalyst layer, the lower graphite film used for forming the wiring pattern) is, for example, Although the film thickness is arbitrary, desirably, the film thickness is less than the wiring width so that the aspect ratio of the wiring is 2 or less. The thinner the film, the better.

  The graphite film (including the catalyst layer) is not only formed on a flat substrate, but a wiring pattern or the like may be formed in advance on the substrate, and the catalyst and the graphite film may be formed at least on the side and bottom surfaces of the pattern. Furthermore, when the base material (substrate) is made of a metal such as copper, the heat treatment in the graphite film forming step may be performed while passing an electric current through the base material. Further, after the formation of the graphite film, a heating (annealing) treatment may be performed while passing an electric current through the base material. According to this, a graphite film including a graphene structure in which carbon atoms are finely oriented can be obtained by so-called electro-migration.

(4) Wiring pattern formation process Next, the process of forming the wiring pattern which consists of a graphite film formed as mentioned above is explained in full detail. As described above, as a process for forming a desired wiring pattern, a procedure for performing a pattern formation process after formation of a graphite film, and a procedure for performing pattern formation after formation of a catalyst layer and before formation of a graphite film There is.

  In the former procedure, first, a graphite film is formed on the entire surface of the substrate by the above-described graphite film forming step, and then a wiring resist pattern is formed using photolithography. Subsequently, portions other than the wiring are selectively removed by, for example, dry etching, and the graphite film is left only in the wiring pattern portion. Note that a gas containing oxygen can be used for removing the graphite film (dry etching).

  A gas containing fluorine or chlorine can be used for etching the catalyst layer remaining after etching the graphite film. After forming a wiring pattern made of a graphite film in this way, the wiring surface is coated by a normal plasma CVD method or the like.

In the latter procedure, after the catalyst layer is deposited on the entire surface of the substrate, a wiring pattern is formed on the catalyst layer by photolithography before forming the graphite film. For the pattern formation of the wiring, for example, normal dry etching using a fluorine-containing gas such as chlorine or carbon tetrafluoride (CF ₄ ) can be used. And the said thermal CVD process is performed with respect to the board | substrate including the catalyst layer formed in such a wiring pattern, and a graphite film is formed in the wiring pattern of the catalyst layer.

  In other words, graphite is not formed on the oxide film surface on which no catalyst layer is deposited, so that graphite is not formed. On the other hand, graphite is selectively formed only on the catalyst layer having catalytic action. can do. Thereafter, the wiring surface can be covered with an insulating layer such as an oxide film. The advantage of this process is that it can be a relatively simple process because there is no graphite film removal process by dry etching in the former procedure.

(5) Action and Effect In order to improve the film quality of the graphite film and obtain a low resistance wiring pattern, it is preferable to form the graphite film by high-temperature treatment at 600 ° C. or higher as described above. Since the melting point of the catalyst is approached, the catalyst tends to aggregate. In order to suppress aggregation, two conventionally known typical methods can be used.

  The first conventional method is a method of increasing the thickness of the catalyst layer. However, in this method, for example, when the wiring width is 50 nm or less due to product requirements or the like, if the catalyst layer has a thickness of 50 nm or more, the aspect ratio (h) and width (w) of the wiring pattern ( h / w) is 1 or more, and the thickness of the graphite film is further added thereto. For this reason, not only wiring processing becomes difficult, but also the capacitance between wiring increases, wiring delay increases (processing speed decreases) in proportion to the product CR of wiring resistance (R) and wiring capacitance (C), and consumption Electric power may also increase.

  The second conventional method is a method using tungsten, titanium or the like having a high melting point as a catalyst. According to the experiment of the present inventor, when titanium or the like is used as a catalyst, the catalyst does not aggregate even if the thickness is about 10 nm or less. However, when the thermal CVD process is performed, unlike a case where Ni or the like is used as a catalyst, there is a possibility that a sufficiently thick graphite film may not be formed.

  Here, the formation and quality of the graphite film can be confirmed by Raman spectrum analysis. Raman spectrum analysis is a method of irradiating an object with a laser and analyzing the scattered light through a spectroscope. By observing the frequency of the detected light, graphite is properly formed on the catalyst layer. It can be determined whether or not the film quality of the formed graphite is good.

In the Raman spectrum, and near 1590 cm ^-1, G respectively in the vicinity of 1350 cm ^-1, a peak generally referred to as D is observed, G denotes a graphite structure, D is a peak reflecting the defect structure, G / The larger the peak intensity ratio of D, the better the crystallinity as graphite and the better the film quality.

  In the method for forming a wiring pattern of the present embodiment, since the catalyst layer containing the first component and the second component as described above is used, aggregation can be suppressed even if the treatment is performed at a high temperature during the formation of the graphite film. At the same time, a high-quality graphite film having a large G / D peak intensity ratio in the Raman spectrum analysis can be formed by the catalytic action of the first component. Alternatively, it is possible to control the diffusion of carbon more than necessary into the first component and to control the deposition of a suitable amount of carbon, so that a high-quality graphite film can be formed. As a result, a high aspect ratio can be maintained even with a fine wiring pattern, and a wiring using a graphite film that is easy to manufacture and has a small capacitance between wirings can be formed.

  Further, when the catalyst layer is formed using electroless plating, there is an advantage that a graphite film having a uniform film quality can be easily deposited on the substrate even if the substrate is not flat. That is, since the film quality of the graphite film depends on the film thickness of the catalyst layer as shown in FIG. 2, the film thickness uniformity of the catalyst is required to deposit a graphite film having a uniform film quality. When a catalyst is formed on a concavo-convex substrate by sputtering, it is difficult to make the film thickness uniform because a shadow is formed by a pattern. On the other hand, when electroless plating is used, a film is deposited by a chemical reaction on the surface, so that a uniform film thickness can be formed anywhere as long as the plating solution is immersed, as schematically shown in FIG. This leads to the uniformity of the quality of the graphite film. As an advantage that can be deposited on the substrate, there is an effect that the wiring width can be effectively widened by the three-dimensional shape even if the lateral dimension is reduced.

<< Embodiment 2 >>
This embodiment
A carbon compound layer forming step of forming a carbon compound layer composed of a carbon compound on the substrate;
A first component that diffuses carbon and a second component that suppresses aggregation of the first component and / or diffusion of carbon to the first component on a surface of the carbon compound layer opposite to the base. A catalyst layer forming step of forming a catalyst layer containing components,
Heating the substrate having the carbon compound layer and the catalyst layer, and forming a graphite film including a graphene structure from the carbon compound layer; and
Having
1 is an embodiment of a wiring pattern forming method (second method) characterized by the above.

  In the present embodiment, as in the first embodiment, a graphite film is formed using a catalyst layer containing a first component and a second component, and a wiring pattern is formed from the graphite film. In the first embodiment, the graphite film is formed above the catalyst layer. However, in this embodiment, a carbon source layer (for example, an organic silane compound) is deposited and heated (annealed) under the catalyst layer. Thus, a graphite film is formed under the catalyst layer.

(1) Wiring Forming Method An example of the wiring pattern forming method of this embodiment will be described with reference to FIG. As shown in FIG. 4A, after an insulating film such as a silicon oxide film is formed on the substrate by, for example, a vapor phase growth method, carbon is formed on the silicon oxide film as shown in FIG. Deposit a compound layer.

  Subsequently, as shown in FIG. 4C, a catalyst layer is formed on the carbon compound layer by using a sputtering method, a vapor phase growth method, or the like. Then, as shown in FIG. 4D, for example, a heating (annealing) process is performed using an inert furnace or the like to form a graphite film under the catalyst layer.

  Similar to the first embodiment, this heating (annealing) treatment may be performed while passing a current through the base material (substrate) made of a metal such as copper. Further, a metal layer such as copper may be formed on the upper surface of the catalyst layer, and a heating (annealing) treatment may be performed while an electric current is passed through the metal layer. Furthermore, as will be described later, the catalyst layer may be removed after the formation of the graphite film, and then a heating (annealing) treatment may be performed while an electric current is applied to the substrate. According to this, a graphite film including a graphene structure in which carbon atoms are finely oriented can be obtained by so-called electro-migration.

  In this embodiment, since the graphite film is formed under the catalyst layer, the catalyst layer can be easily removed after the formation of the graphite film. A wiring pattern made of a graphite film can be formed by forming a wiring resist pattern on the graphite film thus formed and selectively removing portions other than the wiring by dry etching or the like.

Alternatively, as shown in FIG. 4C, a wiring pattern may be formed on the catalyst layer after the catalyst layer is formed on the substrate. In this case, in the step of forming the graphite film of FIG. 4D, the graphite film is not formed at the portion where there is no catalyst layer, while the graphite film is formed only on the patterned catalyst layer.
Hereinafter, each step in the wiring pattern forming method of this embodiment will be described in detail.

(2) Carbon Compound Layer Regarding the formation of the carbon compound layer, first, the composition of the carbon compound layer formed will be described. Specifically, the layer composed of the carbon source of the present embodiment is basically not limited as long as it contains carbon.

  For example, a carbon compound layer such as amorphous carbon may be used, and an organic silane compound having a silanol group serving as a carbon source (for example, alkylsilane, alkoxysilane, allylsilane, aminosilane, etc.) may be used. Examples include ethylamino / ethylamino / propyltrimethoxysilane (TAMS) and 3-aminopropyltriethoxysilane (APTES). Moreover, a part of carbon may be substituted with nitrogen or sulfur. The film thickness of the carbon compound layer is not particularly limited, but is preferably 10 nm, for example.

  Moreover, the carbon compound layer containing the organosilane molecule is formed in a thickness of several nm uniformly on the surface of the oxide film of the base material in a form close to a self-assembled monolayer. Further, by using organic molecules having a large molecular weight, the amount of carbon and the film thickness contained in the organic molecular film can be increased.

(3) Carbon compound layer forming step Subsequently, an example of a method for forming the carbon compound layer will be described in detail. In this embodiment, the carbon compound layer is formed on the substrate (and below the catalyst layer described later) as a carbon source for the graphite film.

  Examples of the base material include a metal substrate, a glass epoxy substrate, and a silicon substrate. “Forming on a base material” includes both the case of forming directly on a substrate and the case of forming a catalyst on silicon oxide by coating a silicon oxide film on the surface of the substrate. The case where it is formed on various elements and wirings of the apparatus is also applicable when it is formed on the substrate.

  As a method for forming a carbon compound on such a substrate, generally, a vacuum deposition method, a CVD method, a dipping method for supplying liquid, a spin coating method, a spray coating method, or the like can be performed. Further, an element such as Pd having a catalytic action in electroless plating may be mixed into the carbon compound layer.

  In addition, it is desirable to coat | cover with the film | membrane which consists of a compound containing the element which forms a silane coupling like a said oxide film (O) etc. on a base material, for example. By doing so, a carbon compound layer can be made to adsorb | suck to a base material suitably.

(4) Catalyst layer Since the composition and formation method of the catalyst layer are basically the same as those in the first embodiment, detailed description thereof is omitted here.

  However, the thickness of the catalyst layer in this embodiment may be in the range of 1 to 5000 nm. In this embodiment, since only the catalyst layer can be removed after the formation of the graphite film as described above, it is not necessary to consider the influence of the thickness of the catalyst layer on the ratio (aspect) to the wiring width. Therefore, it is preferable to deposit with a thickness as much as possible from the viewpoint of suppressing aggregation of the catalyst layer.

(5) Graphite film formation process Next, in this embodiment, a graphite film is formed by performing a heating (annealing) process. As the heating method, in addition to an inert furnace and a vacuum heating furnace, a heat treatment using a laser or electron beam irradiation apparatus can be given.

  The temperature in the heat treatment is preferably 600 ° C., but the temperature is not particularly limited. For example, it may be in the range of 350 ° C. to 1000 ° C. For improving the film quality of the graphite film, 500 ° C. to 750 ° C. The range of ° C. is preferable, but can be appropriately set according to the film thickness, the crystal state of the catalyst layer, and the like. Similarly, the heating time can be appropriately set within a range of 10 minutes to 60 minutes.

  And it can cool at a cooling rate, such as 10 degree-C / sec, in the same inert atmosphere etc. after a heating. The cooling rate in this cooling can also be adjusted as appropriate according to the thickness of the graphite film to be formed.

  Depending on the function of the catalyst layer containing the first component and the second component, the carbon supplied to the catalyst layer from the carbon compound layer formed under the catalyst layer is not only above the catalyst layer (opposite the base). It is deposited below it.

  When the catalyst layer is composed of the first layer containing the first component and the second layer containing the second component in a laminated body, the first layer containing the first component that is mainly easy to diffuse carbon is placed on the lower side (substrate and A second component that is disposed on the carbon compound layer side) and includes a second component mainly having a substance that suppresses aggregation of the first component and / or a substance that suppresses diffusion of carbon into the first component on the first layer. It is good to laminate two layers.

  By laminating in such a vertical relationship, the carbon diffused in the catalyst layer of the first component is disturbed by the second component layer laminated thereon and is not deposited upward, but is deposited below it. It will be. Therefore, a graphite film can be formed under the catalyst layer.

  After the graphite film is formed under the catalyst layer, the catalyst layer is selectively removed using a mixed acid aqueous solution containing nitric acid, hydrochloric acid, hydrogen peroxide, or other well-known etching solution for nickel or cobalt. . In this way, only the graphite film can be left on the oxide film of the substrate.

(6) Wiring pattern forming process Subsequently, a wiring pattern is formed from the graphite film formed as described above. As described above, as a process for forming a desired wiring pattern, the pattern is formed after the graphite film is formed. There are a procedure for forming and a procedure for forming a pattern after forming the catalyst layer and before forming the graphite film. Since both procedures for forming the wiring pattern are the same as those in the first embodiment, detailed description thereof is omitted here.

(7) Function and Effect As described in Non-Patent Document 2 above, in the technique of depositing and heating a Ni layer as a catalyst layer on an amorphous carbon layer, carbon diffuses in the catalyst layer and is deposited above it. A graphite film is formed on the surface of the catalyst layer. Therefore, the catalyst layer cannot be removed as in this embodiment, and the catalyst layer remains under the graphite film.

  In the wiring pattern forming method of the present embodiment, the first component that is formed on the carbon compound layer and easily diffuses carbon, the substance that suppresses aggregation of the first component, and / or the carbon of the first component Since a catalyst containing a second component having a substance that suppresses diffusion is used, the carbon supplied to the catalyst layer from the carbon compound layer formed under the catalyst layer becomes the first component and the second component. It is deposited below the catalyst layer by the function of the catalyst layer.

  Alternatively, when a catalyst is formed by laminating the first component and the second component, the first layer containing the first component that easily diffuses carbon is disposed on the lower side (substrate and carbon layer side), and the first layer is disposed thereon. By laminating the second layer containing the second component having the substance that suppresses the cohesiveness and / or the substance that suppresses the diffusion of carbon, the carbon diffused in the catalyst layer of the first component is laminated thereon. It is disturbed by the second component layer and is not deposited upward, but is deposited below it. Therefore, a graphite film can be formed under the catalyst layer.

  Since the catalyst layer can be selectively removed after the graphite film is formed under the catalyst layer, only the graphite film can be left on the oxide film of the substrate.

  Further, since the catalyst layer can be removed and only the graphite film can be left on the oxide film of the substrate, the resistance can be reduced by the electric conductivity characteristic of graphite when wiring is used. Further, since the height of the wiring is not raised by the thickness of the catalyst layer, a high aspect ratio can be easily obtained.

  Although one embodiment of the present invention has been described above, typical examples of the present invention will be described below. Examples 1 to 5 relate to the first method, and Examples 6 to 7 relate to the second method.

<< Example 1: Use of Ni-W catalyst layer formed by sputtering >>
First, an insulating film of a silicon oxide film was formed on the surface of a silicon substrate by a CVD method. Then, on the silicon oxide film, for example, a sputtering method is performed using an alloy target made of nickel (Ni: first component) and tungsten (W: second component) having element composition ratios of 10% and 90%, respectively. A 10 nm thick Ni—W alloy was deposited as a catalyst layer. In this example, an experiment was performed under the conditions of argon as a sputtering gas, a pressure of 1 mPa, and a DC power of 90 W. As a result, the compositions of Ni and W in the Ni—W alloy were about 11 mass% and about 89 mass, respectively. %Met.

  Subsequently, the substrate on which the catalyst layer was formed in this manner was placed in a CVD (chemical vapor deposition method) apparatus, and a graphite film was formed by performing a heat CVD process with the surface of the catalyst layer exposed. This thermal CVD process is performed by bubbling ethanol with argon gas to generate argon gas containing ethanol vapor, and supplying the argon gas to the surface of the catalyst layer heated to 600 ° C. A good graphite film was formed.

<< Example 2: Use of Ni-B catalyst layer formed by sputtering >>
First, an insulating film of a silicon oxide film was formed on the same substrate surface as that used in Example 1 by the CVD method. Then, a sputtering method was performed on the silicon oxide film using an alloy target composed of Ni and B having elemental composition ratios of 85% and 15%, respectively, to deposit a Ni—B alloy having a thickness of 10 nm. Argon was used as the sputtering gas and the pressure was 1 mPa and the direct current power was 90 W. The composition ratios of Ni and B in the Ni-B alloy were 90% and 10%, respectively.

  Subsequently, the substrate on which the catalyst layer was thus formed was placed in a CVD (Chemical Vapor Deposition) apparatus, and a graphite film was formed by performing a heat CVD process with the catalyst surface exposed. This thermal CVD process was performed by bubbling ethanol with argon gas to generate argon gas containing ethanol vapor and supplying the argon gas to the surface of the catalyst layer heated to 600 ° C. As a result, a good graphite film having a thickness of 10 nm could be formed.

  And the Raman spectrum of the graphite film (Comparative Examples 1 and 2) obtained when using the catalyst of only nickel or titanium as a comparative example and the graphite film when using nickel-boron as a catalyst as mentioned above is shown. As a result of comparison, it was confirmed that the graphite film of this example was superior to the graphite film of the comparative example.

  Therefore, as in the first method, doping the typical element into nickel increases the recrystallization temperature of the catalyst layer and makes aggregation less likely to occur, so that the wiring width is 50 nm or less compared to the conventional method. It has also been found that wiring can be formed using a graphite / catalyst laminate structure that is easy to manufacture and has a small inter-wiring capacity with a reduced aspect ratio. Further, when boron is doped into nickel, as described above, carbon diffusion to nickel can be suppressed, and boron atoms are doped into the obtained graphite film, and it is expected that the electrical characteristics thereof are improved.

  In addition, this effect is not limited only to this Example 2, It is obtained by the combination of the 1st component of this invention, and the 2nd component which is a typical element, It is the characteristic effect of this invention. .

<< Example 3: Use of Ni-B catalyst layer formed by electroless plating >>
First, an insulating film of a silicon oxide film was formed on the same substrate surface as that used in Example 1 by the CVD method. Then, a palladium (Pd) film was deposited on the silicon oxide film. This Pd film was formed in order to act as a catalyst for depositing a Ni-B alloy or the like during electroless plating.

  Next, a substrate with a Pd film attached to the surface was coated with a Ni-B plating bath (0.1 mol of nickel sulfate hexahydrate, 0.2 mol of citric acid, 0.05 mol of dimethylamine borane, and tetra A solution adjusted to pH = 9 using methylammonium hydride as a pH adjusting agent) was immersed at 70 ° C. to deposit a 10 nm Ni—B film.

  Subsequently, the substrate on which the Ni—B catalyst layer was formed in this way was placed in a CVD (chemical vapor deposition) apparatus, and a graphite film was formed by performing thermal CVD processing with the catalyst surface exposed. . This thermal CVD process was performed by bubbling ethanol with argon gas to generate argon gas containing ethanol vapor and supplying the argon gas to the surface of the catalyst layer heated to 600 ° C. As a result, a good graphite film having a thickness of 10 nm could be formed.

<< Example 4: Use of Co-W-P-B catalyst layer formed by electroless plating >>
First, an insulating film of a silicon oxide film was formed on the same substrate surface as that used in Example 1 by the CVD method. Then, a palladium (Pd) film was deposited on the silicon oxide film. This Pd film was formed in order to act as a catalyst for depositing a Co—W—P—B alloy during electroless plating.

  Next, 0.082 mol of cobalt sulfate heptahydrate, 0.502 mol of boric acid, 0.169 mol of sodium phosphinate, 0.03 mol of sodium tungstate and 0.492 mol of sodium citrate are used as components. A plating solution whose pH was adjusted to 9 with potassium was prepared. The plating solution was heated to 80 ° C., and the substrate with the Pd film attached to the surface was immersed in the plating solution. Then, a Co—W—P—B alloy film having a thickness of 10 nm is deposited on the substrate, Co is 0.85, W is 0.04, P is 0.11, and B is hardly detected. A -B catalyst layer could be obtained.

  In this example, the test was performed with the composition of tungsten being about 5% by mass, but it was possible to change the composition depending on the concentration of sodium tungstate in the plating solution.

  Subsequently, the substrate on which the Co—W—P—B catalyst layer is formed is placed in a CVD (Chemical Vapor Deposition) apparatus, and a graphite film is formed by performing a thermal CVD process with the surface of the catalyst layer exposed. Formed. This thermal CVD process was performed by bubbling ethanol with argon gas to generate argon gas containing ethanol vapor and supplying the argon gas to the surface of the catalyst layer heated to 600 ° C. As a result, a good graphite film having a thickness of 10 nm could be formed.

<< Example 5: Use of Co-WP-B / Ni-B catalyst layer formed by electroless plating >>
First, an insulating film of a silicon oxide film was formed on the same substrate surface as that used in Example 1 by the CVD method. Then, a palladium (Pd) film was deposited on the silicon oxide film. Subsequently, the substrate with the Pd film attached was immersed in a Ni-B plating bath to deposit a 2 nm Ni-B layer.

  Next, 0.082 mol of cobalt sulfate heptahydrate, 0.502 mol of boric acid, 0.169 mol of sodium phosphinate, 0.03 mol of sodium tungstate and 0.492 mol of sodium citrate are used as components. A plating solution whose pH was adjusted to 9 with potassium was prepared. The plating solution was heated to 80 ° C., and the substrate on which the Ni—B layer was deposited was immersed in the plating solution. Then, a Co—W—P—B alloy film having a thickness of 10 nm was deposited on the Ni—B layer on the substrate, and a Co—W—P—B / Ni—B catalyst layer could be obtained.

  Subsequently, the substrate on which the Co—WP—B / Ni—B catalyst layer is formed is placed in a CVD (chemical vapor deposition) apparatus, and thermal CVD treatment is performed with the catalyst layer surface exposed. To form a graphite film. This thermal CVD process was performed by bubbling ethanol with argon gas to generate argon gas containing ethanol vapor and supplying the argon gas to the surface of the catalyst layer heated to 600 ° C. As a result, a good graphite film having a thickness of 10 nm could be formed.

<< Example 6: Carbon compound layer: Use of amorphous carbon layer >>
First, an insulating film of a silicon oxide film was formed on the same substrate surface as that used in Example 1 by the CVD method. Then, a carbon compound layer made of amorphous carbon was deposited to a thickness of 10 nm on the substrate by a vacuum evaporation method using a carbon rod as a source.

  Subsequently, as a catalyst layer on the amorphous carbon layer, sputtering was performed using an alloy target composed of nickel and tungsten each having an elemental composition ratio of 50% by mass, and a nickel-tungsten alloy layer having a thickness of 100 nm was formed as a catalyst layer. As deposited. Note that the sputtering gas was argon, the pressure was 1 mPa, and the DC power was 100 W.

Subsequently, in order to form a wiring pattern, the catalyst layer was processed into a wiring pattern by photolithography. This wiring processing was performed by dry etching using a carbon tetrafluoride (CF ₄ ) -containing gas.

  The substrate on which the carbon compound layer on which the wiring pattern was formed and the catalyst layer was deposited was heated at 600 ° C. for 30 minutes in a nitrogen atmosphere. And after the heating, it was similarly cooled in a nitrogen atmosphere at a cooling rate of 10 ° C./second. Then, carbon was deposited underneath by the function of the catalyst layer. Therefore, a graphite film was formed under the catalyst layer processed into the wiring pattern (between the catalyst layer and the substrate).

  Subsequently, the catalyst layer on the graphite film was selectively removed by etching using a mixed acid aqueous solution. In this way, a wiring pattern made of a graphite film having a film thickness of 10 nm from which the catalyst layer was removed could be formed.

«Example 7: Carbon compound layer: Use of organosilane compound layer»
First, an insulating film of a silicon oxide film was formed on the same substrate surface as that used in Example 1 by the CVD method. Then, the substrate on which the silicon oxide film is formed is immersed in a 60 ° C. toluene solution containing 1% by mass of aminoethylamino / ethylamino / propyltrimethoxysilane (TAMS), which is an organic silane compound. The molecular layer was adsorbed.

  Thereafter, the substrate was washed with methanol, and an organosilane compound layer was formed thereon. This organosilane compound layer was formed in a thickness of several nanometers uniformly on the surface of the oxide film of the substrate in a form close to a self-assembled monolayer. Moreover, the carbon amount and film thickness contained in the organic molecular film could be increased by using a compound having a large molecular weight.

  Subsequently, the substrate on which the organosilane compound layer was deposited was immersed in a palladium chloride solution, and palladium (Pd) was adsorbed on organic molecules to form a Pd film. This Pd film was formed to act as a catalyst in the next step, Ni-B electroless plating.

  Next, Ni-B plating bath (0.1 mol of nickel sulfate hexahydrate, 0.2 mol of citric acid, 0.05 mol of dimethylamine borane, pH = 9 using tetramethylammonium hydride as a pH adjusting agent) The solution was adjusted at 70 ° C. to deposit a 40 nm Ni—B alloy layer.

  Then, the substrate on which the organosilane compound layer and the catalyst layer were deposited was heated in an inert furnace at 600 ° C. for 30 minutes in a nitrogen atmosphere. And after heating, when it was similarly cooled in a nitrogen atmosphere at a cooling rate of 10 ° C./second, a graphite film was formed under the catalyst layer (between the catalyst layer and the substrate). FIG. 5 shows a transmission electron micrograph of the substrate in a state before the graphite film is formed as described above and the catalyst layer is removed by etching.

  Subsequently, the catalyst layer on the graphite film was selectively removed by etching using a mixed acid aqueous solution. In this way, a graphite film from which the catalyst layer was removed could be formed.

  Thereafter, a wiring resist pattern was formed on the graphite film formed by removing the catalyst layer using photolithography. Subsequently, the graphite film other than the wiring pattern was selectively removed by dry etching using a gas containing oxygen. After forming the graphite film into a wiring pattern in this way, unnecessary photoresist was removed, and the wiring surface was coated by plasma CVD. In this way, a desired wiring pattern with good quality could be obtained.

  As shown in FIG. 5, a graphite film was formed between the catalyst layer made of a nickel-boron alloy layer as a catalyst layer and the oxide layer of the substrate by the wiring pattern forming method of this embodiment.

Table 1 below summarizes the contents of the above examples.

Claims (11)

A first component comprising at least one element selected from the group consisting of nickel, cobalt and iron that diffuses carbon on the substrate; and aggregation of the first component and / or carbon to the first component A second component containing an element of boron or phosphorus that suppresses diffusion, and a catalyst layer forming step of forming a catalyst layer comprising:
A graphite film forming step of forming a graphite film including a graphene structure on a surface of the catalyst layer opposite to the base;
Having
A method of forming a wiring pattern characterized by the above. The carbon diffusion coefficient D1 of the first component and the carbon diffusion coefficient D2 of the second component satisfy the relational expression: D1> D2,
The method for forming a wiring pattern according to claim 1. The catalyst layer is composed of an alloy layer containing the first component and the second component;
The method for forming a wiring pattern according to claim 1, wherein: The catalyst layer is composed of a laminate of a first layer containing the first component and a second layer containing the second component;
The method for forming a wiring pattern according to claim 1, wherein: The catalyst layer is composed of nickel-boron, cobalt-boron, nickel-tungsten-boron, nickel-tungsten-phosphorus, cobalt-tungsten-boron or cobalt-tungsten-phosphorus ;
The method for forming a wiring pattern according to claim 1, wherein: A carbon compound layer forming step of forming a carbon compound layer composed of a carbon compound on the substrate;
A first component containing at least one element selected from the group consisting of nickel, cobalt, and iron that diffuses carbon on the surface of the carbon compound layer opposite to the base material, and aggregation of the first component And / or a second component containing a boron or phosphorus element that suppresses the diffusion of carbon into the first component, and a catalyst layer forming step of forming a catalyst layer comprising:
Heating the substrate having the carbon compound layer and the catalyst layer, and forming a graphite film including a graphene structure from the carbon compound layer; and
Having
A method of forming a wiring pattern characterized by the above. The carbon diffusion coefficient D1 of the first component and the carbon diffusion coefficient D2 of the second component satisfy the relational expression: D1> D2,
The method of forming a wiring pattern according to claim 6 . The catalyst layer is composed of an alloy layer containing the first component and the second component;
The method for forming a wiring pattern according to claim 6 or 7 , wherein: The catalyst layer is composed of a laminate of a first layer containing the first component and a second layer containing the second component;
The method for forming a wiring pattern according to claim 6 or 7 , wherein: The catalyst layer is composed of nickel-boron, cobalt-boron, nickel-tungsten-boron, nickel-tungsten-phosphorus, cobalt-tungsten-boron or cobalt-tungsten-phosphorus ;
The wiring pattern forming method according to any one of claims 6-9, characterized in. The carbon compound is amorphous carbon or an organosilane compound;
The wiring pattern forming method according to any of claims 6 to 10, characterized in.