JP2012184449A - Method for forming metal thin film, metal thin film, and device for forming metal thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a metal thin film having a low impurity content, excellent in a step coverage property, and prepared without using high vacuum.SOLUTION: The method for forming a metal thin film includes a raw material transfer step of transferring an organic metal compound raw material onto a film formation target having been loaded into a vacuum chamber, and a reactive gas transfer step of bringing a reactive gas into contact with a heated metal catalyst body and thereafter transferring the reactive gas onto the film formation target having been loaded in the vacuum chamber. The organic metal compound raw material and/or the reactive gas exclusively includes one or more atoms selected from a carbon atom, a nitrogen atom, a hydrogen atom, a silicon atom, a phosphor atom, a boron atom and a metal atom.

Description

  The present invention relates to a method for forming a metal thin film, a metal thin film, and a metal thin film forming apparatus.

  In recent years, technological progress in the technical fields such as semiconductor elements, flat panel displays (FPD), and solar cells has been remarkable, and research and development on metal thin films used as electrodes, barrier metals, and the like have been actively conducted.

  In general, transition elements are often used as the material for such a metal thin film, and techniques such as PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) are known as film forming methods.

The PVD method is a film forming method called a physical vapor deposition method, and is characterized in that a thin film is formed by evaporating a substance by physical means, and sputtering and vapor deposition are classified into this method.
The PVD method has the merit that a high-purity film can be produced. However, since a vacuum higher than a high vacuum is required as a film forming condition, a large capital investment is required for the exhaust system, and a film is formed. There is a drawback that the step coverage of the film is poor.

  In particular, when manufacturing a semiconductor element, there is a problem that due to the poor step coverage, troubles such as tearing of the metal thin film and generation of voids occur, and the reliability of the element is lowered. In addition, film formation on large-area FPDs and solar cells has a problem that an expensive equipment investment is required because the apparatus is enlarged.

  The CVD method is a film forming method called a chemical vapor deposition method, in which a metal raw material is supplied in a gaseous state onto a substrate, and a desired film is formed by dissociation / reaction by a chemical reaction on the gas phase or the substrate surface. There is a feature. Compared with the PVD method, since a high vacuum is not required, the exhaust system tends to be inexpensive. As a method classified into the CVD method, there are film forming methods such as a thermal CVD method, a PECVD method, a HWCVD method, and an ALD method.

  The thermal CVD method is a method in which a metal raw material is conveyed to a substrate surface in a gaseous state, and a film is formed using thermal decomposition or surface reaction on a heated substrate. Although it depends on the type of surface reaction, it is generally excellent in step coverage because it has a low sticking probability.

  The PECVD method is a method in which a metal raw material is appropriately decomposed in a gas phase using plasma energy and then transported to the substrate surface to form a film. When a volatile raw material is used as the metal raw material, the film can often be formed.

  The HWCVD method is also called a Cat-CVD method, and is a method in which a metal raw material is dissociated by bringing it into contact with a hot wire functioning as a catalyst and transported to the substrate surface in that state to form a film. As a catalyst, a mesh-like metal may be used instead of a wire. The HWCVD method has not only the advantage that the exhaust system is inexpensive, but also the advantage that the area can be increased simply by stretching the wire.

  The ALD method (Atomic Layer Deposition) is a film forming method also called atomic layer deposition method. After the metal material is transported until it is saturated and adsorbed on the substrate surface, the residual gas is exhausted and then the reaction gas is transported to the substrate surface. Then, the surface reaction is promoted to deposit one atomic layer or several atomic layers to form a film.

At this time, since only the metal raw material is transported, the film is not formed but only adsorbed to the surface of the substrate, so that the step coverage tends to be good, and high-purity film formation is possible depending on the conditions.
A general ALD method forms a film using a reaction mechanism similar to that of a thermal CVD method. However, as in the HWCVD method, Patent Document 1 discloses a method of dissociating a metal raw material by bringing it into contact with a hot wire. (Hereinafter referred to as “HWARD method”).

  Non-Patent Document 1 discloses a technique for forming a metal thin film by thermal CVD at atmospheric pressure using biscyclopentadienyl cobalt (cobaltene) as a metal raw material.

JP 2006-28572 A

Journal of Crystal Growth 114 1991, pp 364-372

  However, the thermal CVD method often includes reaction by-products and the like, and it is difficult to obtain a high-purity film, and there is a disadvantage that the resistance is higher than the resistivity of bulk metal. In addition, metal raw materials that can be used for thermal CVD film formation and film formation conditions are limited, and it is difficult to obtain a metal thin film with high purity and good step coverage. In addition, many of the metal raw materials used in the thermal CVD method contain oxygen and halogen, which has the disadvantage of adversely affecting the film quality of the metal thin film formed.

  In addition, the PECVD method includes ionized reactive species in addition to the radical reactive species, and thus has a disadvantage that the adhesion rate is high and the step coverage is inferior to that of the thermal CVD method. In addition, there are inconveniences that the base is damaged by plasma and that impurities are more easily contained than in the thermal CVD method.

  Also, unlike the PECVD method, the HWCVD method does not damage the underlayer, but if a metal raw material is used, a metal species is deposited on the wire or on the insulator portion of the wire, causing a short circuit. There was a disadvantage that it was not suitable for the membrane.

In addition, since the ALD method is basically the same as the thermal CVD method, there is a disadvantage that the metal raw materials and film forming conditions that can be used are limited.
In addition, the method described in Patent Document 1 uses a tungsten material containing oxygen or halogen as the metal material, and there is a disadvantage that the metal material that can be used is limited. In addition, since the metal raw material contains oxygen and halogen, there is a disadvantage that these adversely affect the film quality of the formed metal thin film.
In addition, since the thermal CVD method described in Non-Patent Document 1 is performed under atmospheric pressure, there is a disadvantage that the step coverage of the formed metal thin film is poor.

  Under such a background, there has been a demand for a film forming method for forming a metal thin film without using a high vacuum with low impurities, good step coverage, but an effective and appropriate method has not been provided. It was a fact.

In order to solve the above problems, the present invention employs the following configuration.
That is, the invention according to claim 1 is a material transporting step for transporting an organometallic compound raw material onto a film forming object placed in a vacuum chamber, and a reactive gas is brought into contact with a heated metal catalyst body. And a reactive gas transporting step of transporting onto the film forming object placed in the vacuum chamber.

  The invention according to claim 2 is characterized in that the organometallic compound raw material and / or the reactive gas is selected from a carbon atom, a nitrogen atom, a hydrogen atom, a silicon atom, a phosphorus atom, a boron atom, and a metal atom. The method for producing a metal thin film according to claim 1, comprising only two or more atoms.

The invention according to claim 3 is characterized in that the organometallic compound raw material contains an organometallic compound represented by the following chemical formula (1). Is the method. However, in the chemical formula (1), M ₁ is any _one of cobalt, nickel, iron, manganese, ruthenium and chromium, and R _{1 to} R ₅ are hydrogen or carbonized represented by C _n H _{2n + 1} where n is 1 or more. Hydrogen.

The invention according to claim 4 is characterized in that the organometallic compound raw material contains an organometallic compound represented by the following chemical formula (2). Is the method. However, in the chemical formula (2), _{M 2} is tungsten, a molybdenum or titanium _is R 6 _{to R 10} is a hydrocarbon hydrogen or n is represented by 1 or more _C n _{H 2n + 1.}

The invention according to claim 5 is characterized in that the organometallic compound raw material contains an organometallic compound represented by the following chemical formula (3). Is the method. However, in the chemical formula (3), M ₃ is platinum, niobium, zirconium or titanium, R _{11 to} R ₁₅ are hydrogen or a hydrocarbon represented by C _n H _{2n + 1 in} which n is 1 or more, and R ₁₆ to R ₁₈ is a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more.

  The invention according to claim 6 is characterized in that the reactive gas contains at least one of ammonia, dimethylhydrazine, methylamine, dimethylamine, silane, disilane and hydrogen. The method for forming a metal thin film according to claim 5.

  The invention according to claim 7 is characterized in that the metal catalyst body contains at least one of tungsten, platinum, rhodium and ruthenium. It is a film-forming method of the metal thin film of description.

  The invention according to claim 8 is characterized in that the metal catalyst body is heated by energization only during the reactive gas transfer step. This is a method for forming a thin film.

  The invention according to claim 9 is characterized by having a purge step of alternately removing the raw material transfer step and the reactive gas transfer step and removing residual gas in the vacuum chamber between the steps. The method for forming a metal thin film according to any one of claims 1 to 8.

The invention according to claim 10 is characterized in that, in the reactive gas transfer step, the pressure in the vacuum chamber is 1.33 × 10 ² Pa or less. The method for producing a metal thin film according to the item.

  The invention according to claim 11 is characterized in that, in the raw material transporting step, two or more kinds of the organometallic compound raw materials are used and simultaneously or sequentially transported onto the film forming object. 10. The method for forming a metal thin film according to any one of 10 above.

  The invention according to claim 12 is a metal thin film formed by the method for forming a metal thin film according to any one of claims 1 to 11.

  The invention according to claim 13 is a vacuum chamber in which a film forming object can be placed inside, and a raw material capable of transporting an organometallic compound material on the film forming object placed in the vacuum chamber. It has a conveying means, and a reactive gas conveying means capable of conveying the reactive gas after contacting the heated metal catalyst body on the film forming object placed in the vacuum chamber. A metal thin film forming apparatus.

  According to the present invention, a metal thin film can be formed without using a high vacuum with low impurities and good step coverage.

FIG. 1 is a schematic configuration diagram showing a metal thin film forming apparatus according to an embodiment of the present invention. FIGS. 2 (a) to 2 (c) are diagrams showing the energy required for the release of cyclopentadienyl from cobaltene. FIG. 3 is a diagram showing a metal thin film deposition cycle in one embodiment of the present invention. FIG. 4 is a diagram showing a metal thin film deposition cycle in one embodiment of the present invention.

  Hereinafter, a metal thin film forming apparatus and a metal thin film forming method according to an embodiment to which the present invention is applied will be described with reference to the drawings.

<Metal thin film deposition equipment>
First, the metal thin film forming apparatus of this embodiment will be described.
The metal thin film deposition apparatus of the present embodiment is an apparatus capable of depositing a metal thin film by the HWALD method.

  Specifically, as shown in FIG. 1, a film forming apparatus 1 includes a vacuum chamber 2 that can be depressurized, a raw material transport unit 3 that can transport an organometallic compound raw material, and a reactive gas that can transport a reactive gas. And conveying means 4.

A mounting table 5 is provided in the vacuum chamber 2, and the substrate 6 (film forming object) can be freely mounted on the mounting table 5. A heater (not shown) is provided inside the mounting table 5 so that the substrate 6 can be heated.
Further, an exhaust pump 7 is connected to the vacuum chamber 2 via an exhaust pipe (not shown) and an on-off valve (not shown) so that the exhaust can be performed. A pressure gauge (not shown) is provided in the vacuum chamber 2 so that the pressure can be measured.

  Further, in the vacuum chamber 2, a metal catalyst body 8 that is in contact with a reactive gas described later is provided. As the metal catalyst body 8, a well-known material used in the HWCVD method or the like may be used, and not only a metal composed of a single element but also various alloys may be used. In particular, it is preferably substantially made of tungsten, platinum, rhodium or ruthenium. By using the metal catalyst body 8 made of these metals, the film forming temperature can be lowered, so that the progress of side reactions and the diffusion of substances in the substrate can be suppressed, and the step coverage can be improved. it can.

The metal catalyst body 8 is connected to a power source 9 and is configured to be heated by energization. The reactive gas is activated to active species by contact with the metallic color medium 8 heated by this energization.
The metal catalyst body 8 may be disposed in the vacuum chamber 2 or may be installed in another upstream chamber (not shown) separated from the vacuum chamber 2 by a shutter (not shown). Good.

Further, the vacuum chamber 2 is provided with a gas ejection part 10, and the raw material conveying means 3 and the reactive gas conveying means 4 are connected to the gas ejection part 10.
The raw material transport means 3 is generally composed of a raw material supply source 11, a pipe 12 connected to the raw material supply source 11, and a valve 13 attached to the pipe 12. The pipe 12 is connected to the gas ejection unit 10. ing. The pipe 12 is branched upstream of the valve 13 (on the raw material supply source 11 side), and the branched pipe 14 is connected to the pipe 16 via the valve 15.

  The raw material supply source 11 may have any configuration as long as the organic metal compound raw material can be supplied. In this embodiment, the raw material liquid storage tank 17 in which the organic metal compound is stored and the liquid in the raw material liquid storage tank 17 are used. The pipe 18 is connected to the phase portion, and the pipe 12 is connected to the gas phase portion of the raw material storage tank 17. In this case, when an inert gas such as helium is introduced into the raw material storage tank 17 in the pipe 18, the organometallic compound raw material can be accompanied and led out from the pipe 12.

  In the present embodiment, it is assumed that the organometallic compound raw material is liquid at room temperature, and a configuration capable of vaporization by bubbling is adopted. However, such a configuration is not necessarily required. For example, an organic metal compound raw material that is gaseous at normal temperature may be used as a raw material, and when a liquid material is used, it may be gasified by vaporization by a vaporizer or by vaporization by heating.

  The gasified organometallic compound raw material taken out from the gas phase portion of the raw material reservoir 17 is introduced into the vacuum chamber 2 through the gas jetting part 10 by the raw material transport means 3 configured as described above. , Transported onto the substrate 6.

The reactive gas conveying means 4 is generally configured by a reactive gas supply source 21, a pipe 22 connected to the reactive gas supply source 21, and a valve 23 attached to the pipe 22. It is connected to the gas ejection part 10. The reactive gas supply source 21 may have any configuration as long as it can supply reactive gas.
In addition, the pipe 22 is branched upstream of the valve 23 (reactive gas supply source 21 side), and the branched pipe 24 is connected to the pipe 16 via the valve 25.

  The reactive gas derived from the reactive gas supply source 21 is introduced into the vacuum chamber 2 through the gas jetting part 10 by the reactive gas conveying means 4 configured as described above, and comes into contact with the metal catalyst body 8. Above, it is transferred onto the substrate 6.

<Method for forming metal thin film>
Next, a method for forming a metal thin film using the film forming apparatus 1 will be described.
The method for forming a metal thin film according to this embodiment includes a raw material transfer step and a reactive gas transfer step, which will be described first.

Specifically, the raw material transporting process is a process of transporting the organometallic compound raw material onto the substrate 6 placed in the vacuum chamber 2.
As the organic metal compound raw material, various materials can be used, but only one or more atoms selected from a carbon atom, a nitrogen atom, a hydrogen atom, a silicon atom, a phosphorus atom, a boron atom and a metal atom are used. Preferably it consists of. By selecting such a material, it is possible to prevent halogen and oxygen from being contained in the formed metal thin film, and to prevent deterioration in film quality.

Furthermore, the organometallic compound raw material may contain an organometallic compound represented by the chemical formula (1), an organometallic compound represented by the chemical formula (2), or an organometallic compound represented by the chemical formula (3). preferable. However, in the chemical formula (1), M ₁ is any _one of cobalt, nickel, iron, manganese, ruthenium and chromium, and R _{1 to} R ₅ are hydrogen or carbonized represented by C _n H _{2n + 1} where n is 1 or more. Hydrogen. In chemical formula (2), M ₂ is tungsten, molybdenum, or titanium, and R _{6 to} R ₁₀ are hydrogen or a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more. In the chemical formula (3), M ₃ is platinum, niobium, zirconium or titanium, R _{11 to} R ₁₅ are hydrogen or a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more, and R ₁₆ to R ₁₈ is a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more.

Note that the organometallic raw material represented by the chemical formula (1) or the chemical formula (2) is a biscyclopentadienyl compound (common name: metallocene), and its synthesis has been reported with various metals.
By selecting such a material, a metal thin film with fewer impurities can be formed. In addition, when metallocene is used, it is possible to form a film even under reduced pressure by adopting the HWARD method, so that a metal thin film with good step coverage can be obtained.

  Also, the organometallic compound raw material can be used as it is if it is gaseous at room temperature, and if it is liquid, it can be vaporized by bubbling using an inert gas such as helium, vaporized by a vaporizer, or heated. What is necessary is just to use gasified by vaporization. Further, helium or the like may be used as a carrier gas in combination with the organometallic compound raw material.

  For example, when an organometallic compound material that is liquid at room temperature is vaporized by bubbling and used, the liquid in the raw material reservoir 17 in which the organometallic compound material is stored via a pipe 18 as shown in FIG. Inert gas is introduced into the phase part. Then, the organometallic compound material gasified from the gas phase portion of the raw material liquid storage tank 17 may be extracted via the pipe 12.

The vaporized organometallic compound material is introduced into the gas ejection portion 10 via the pipe 12 and then introduced into the vacuum chamber 2. At this time, the valve 15 is closed and the valve 13 is open.
Then, the organometallic compound material introduced into the vacuum chamber 2 is transferred to the substrate 6.
As described above, the organometallic compound raw material is transferred onto the substrate 6 placed in the vacuum chamber 2.

  In the raw material conveyance step, the metal catalyst body 8 disposed in the vacuum chamber 2 is preferably kept in an unheated state without being energized. Thereby, in addition to suppressing the temperature rise of the substrate surface, it is possible to obtain the effects of preventing the deterioration of the metal catalyst body and reducing power consumption.

  Moreover, the organometallic compound raw material does not need to be one type, and may be two or more types. When two or more types are used, they may be transferred onto the substrate 6 simultaneously or sequentially.

Specifically, the reactive gas transporting step is a step of transporting the reactive gas onto the substrate 6 placed in the vacuum chamber 2 after contacting the heated metal catalyst body 8.
A variety of reactive gases can be used, and the reactive gas consists of one or more atoms selected from carbon atoms, nitrogen atoms, hydrogen atoms, silicon atoms, phosphorus atoms, boron atoms, and metal atoms. Is preferred. By selecting such a material, it is possible to prevent halogen and oxygen from being contained in the formed metal thin film, and to prevent deterioration in film quality.

  Furthermore, the reactive gas more preferably contains at least one of ammonia, dimethylhydrazine, methylamine, dimethylamine, silane, disilane, and hydrogen. By selecting such a material, it is possible to form a metal thin film with lower impurities and good step coverage.

In particular, when metallocene is employed as the organometallic compound material, the reactive gas is preferably a gas containing nitrogen atoms.
When H or NH ₂ is not bonded to the metal atom contained in the metallocene, a lot of energy is required to dissociate the metal atom. On the other hand, when H is bonded to a metal atom, not much energy is required to dissociate the metal atom. In particular, when the metal atom is bonded to NH ₂ , the metal atom is dissociated. The energy required for this is small. Therefore, it is preferable that the reactive gas contains a nitrogen atom.

For example, in the case of cobaltcene (M _{1 in the} above chemical formula (1) is cobalt), as shown in FIG. 2A, when H or NH ₂ is not bonded to cobalt, cyclopentadiene is converted from cobaltcene. To dissociate, 50.5 kcal / mol is required. On the other hand, as shown in FIG. 2 (b), when H is bonded to cobalt, only 29.1 kcal / mol is required to release cyclopentadiene from cobaltcene, and FIG. ), When NH ₂ is bonded to cobalt, only about 15.2 kcal / mol is required.
The reactive gas can also be diluted with other inert gas.

  The reactive gas supplied from the reactive gas supply source 21 is introduced into the gas ejection unit 10 via the pipe 22 and then introduced into the vacuum chamber 2. At this time, the valve 25 is closed and the valve 23 is open. Further, when the reactive gas is introduced into the vacuum chamber 2, the reactive gas may be introduced through a shower head 26 provided in the gas ejection unit 10.

The reactive gas introduced into the vacuum chamber 2 comes into contact with the metal catalyst body 8 heated by energization or the like, and is then transferred onto the substrate 6.
By contacting with the heated metal catalyst body 8, the reactive gas becomes at least one of NX _n radical, SiX _n radical (X is hydrogen or hydrocarbon, n is an integer of 1 to 3) and H radical. It is preferably activated to an active species.
As described above, the reactive gas is brought into contact with the heated metal catalyst body 8 and then conveyed onto the substrate 6 placed in the vacuum chamber 2.

Next, the relationship between a raw material conveyance process and a reactive gas conveyance process is demonstrated.
The metal thin film forming method of this embodiment is basically a film forming method by the HWALD method. Therefore, specifically, the organometallic compound raw material is transported onto the substrate 6, the supply of the organometallic compound raw material is stopped in a state where the organometallic compound raw material is saturatedly adsorbed on the substrate 6, and then the reaction is performed on the substrate 6. By supplying the property gas, the organometallic compound raw material is formed on the substrate 6. This process is defined as one cycle, and the cycle is repeated a plurality of times until a metal thin film having a desired film thickness is formed on the substrate 6.

  At this time, the metal thin film is not formed on the substrate 6 only by transporting the organometallic compound raw material, but is formed only after the reactive gas is transported. Since only the organometallic compound raw material that is saturated and adsorbed on the substrate 6 is formed, a thin film is formed in units of one atom or several atoms.

Therefore, in order to obtain a desired film thickness, the raw material transfer process and the reactive gas transfer process are alternately repeated. In this case, the residual gas in the vacuum chamber 2 is removed between the processes. It is preferable to have a purge step.
By having such a purge process, a metal thin film can be formed with higher accuracy.

Switching between the raw material transfer process and the reactive gas transfer process may be controlled by opening and closing the valves 13 and 23. Further, during the raw material transfer process, the reactive gas derived from the reactive gas supply source 21 may be discharged out of the system through the pipes 24 and 16 by closing the valve 23 and opening the valve 25. Conversely, during the reactive gas transfer process, the valve 13 is closed and the valve 15 is opened, so that the organometallic compound raw material may be discharged out of the system via the pipes 14 and 16.
As described above, a metal thin film is formed on the substrate 6 by alternately performing the raw material transport process and the reactive gas transport process.

Incidentally, the pressure in the vacuum chamber 2, in a reactive gas transfer step, preferably to ^{1.33 × 10 2 Pa (= 1Torr} ) or less, in all steps of the film process, 1.33 × ¹⁰ 2 Pa (= 1 Torr) or less, more preferably 6.65 × 10 Pa (= 0.5 Torr) or less in all steps of the film forming process.
By forming the film under such reduced pressure, the step coverage of the formed metal thin film is improved.

Since the method for forming a metal thin film according to this embodiment includes a raw material transfer step and a reactive gas transfer step, a metal thin film with low impurities and good step coverage can be formed.
Moreover, since a high vacuum is not required in the film forming process, the manufacturing apparatus is not expensive. In addition, since the raw material transfer step and the reactive gas transfer step are performed alternately, it is possible to prevent the metal thin film from being deposited on the metal catalyst body.

  In addition, since the organometallic compound raw material or / and the reactive gas consists of only one or more atoms selected from carbon atoms, nitrogen atoms, hydrogen atoms, silicon atoms, phosphorus atoms, boron atoms and metal atoms, It is possible to prevent halogen and oxygen from being mixed into the formed metal thin film, and to form a metal thin film with good film quality.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention can be variously changed in the range which is not limited to the said embodiment and does not deviate from the summary.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

Example 1
In Example 1, the metal thin film forming apparatus shown in FIG. 1 was used, and as shown in Table 1, the substrate was maintained at 350 ° C., and the pressure in the vacuum chamber was set to 2 using an automatic pressure controller (APC). .66 × 10 Pa (= 0.2 Torr). Further, biscyclopentadienyl cobalt (cobaltene) was used as the organometallic compound raw material, ammonia was used as the reactive gas, and tungsten wire was used as the metal catalyst body.

As a film forming method, a raw material bottle containing cobaltcene is first heated to 50 ° C., and supplied with a raw material vapor by helium at a flow rate of 30 sccm for 3 seconds. Next, purging with helium at a flow rate of 30 sccm is performed.
Thereafter, ammonia at a flow rate of 30 sccm is supplied into the vacuum chamber for 9 seconds. In the meantime, a current of 3 A is applied to the tungsten wire to heat it up red.
Then, purging with helium at a flow rate of 30 sccm is performed.
The above steps were taken as one cycle, and as shown in FIG. 3, supply of raw material, purge, supply of ammonia, energization, and purge were repeated.

  As a result, in Example 1, as shown in Table 2, the film forming speed was 0.04 nm / cycle, and the resistivity was 20 μΩcm. Further, after the film formation, the composition of the metal thin film obtained by X-ray photoelectron spectroscopy (XPS) was examined, and all of carbon, oxygen, and nitrogen were 1% or less, which is the lower limit of detection.

(Example 2)
In Example 2, helium was not circulated in the purge process, but vacuuming was performed. As shown in Table 1, a metal thin film was formed under the same conditions as in Example 1.
In Example 2, as shown in Table 2, the film formation rate was 0.05 nm / cycle, and the resistivity was 20 μΩcm. Further, after the film formation, the composition of the metal thin film obtained by X-ray photoelectron spectroscopy (XPS) was examined, and all of carbon, oxygen, and nitrogen were 1% or less, which is the lower limit of detection.

(Examples 3 to 5)
In Examples 3 to 5, the nickel metallocene, manganocene, and ferrocene were used in place of cobalt sen as the organometallic compound raw material, and the other conditions were the same as in Example 1, and the film formation rate and the composition of the metal thin film A simulation was conducted. The results are shown in Table 3.

(Example 6)
In Example 6, the same film forming apparatus as in Example 1 was used, the substrate was kept at 350 ° C., and the pressure in the vacuum chamber was 2.66 × 10 Pa (= 0.2 Torr) using an automatic pressure controller (APC). ).
As the organic metal compound raw material, two kinds of biscyclopentadienyl cobalt (cobaltene) and biscyclopentadienyl tungsten stainless hydride were used, ammonia was used as a reactive gas, and tungsten wire was used as a metal catalyst.

  As a film forming method, a method of simultaneously supplying two kinds of organometallic compound raw materials was adopted. Specifically, first, a raw material bottle containing cobaltcene was heated to 50 ° C., and a raw material bottle containing biscyclopentadienyl tungsten stainless hydride was heated to 100 ° C. Thereafter, helium at a flow rate of 30 sccm is bubbled through each bottle to entrain the raw material vapor, and cobalt cene and biscyclopentadienyl tungsten stent hydride are simultaneously supplied into the vacuum chamber for 3 seconds. Next, purging with helium at a flow rate of 30 sccm is performed.

Thereafter, ammonia at a flow rate of 30 sccm is supplied into the vacuum chamber for 9 seconds. In the meantime, a current of 3 A is applied to the tungsten wire to heat it up red.
Then, purging with helium at a flow rate of 30 sccm is performed.
The above steps were taken as one cycle, and as shown in FIG. 3, supply of raw material, purge, supply of ammonia, energization, and purge were repeated.

  As a result, in Example 6, the film forming speed was 0.04 nm / cycle, and the resistivity was 25 μΩcm. Further, after the film formation, the composition of the metal thin film obtained by X-ray photoelectron spectroscopy (XPS) was examined. As a result, the cobalt composition was 95%, the tungsten composition was 5%, and carbon, oxygen, and nitrogen were both lower detection limits. % Or less.

(Example 7)
In Example 7, the same film forming apparatus as in Example 1 was used, the substrate was kept at 350 ° C., and the pressure in the vacuum chamber was 2.66 × 10 Pa (= 0.2 Torr) using an automatic pressure controller (APC). ).
As the organic metal compound raw material, two kinds of biscyclopentadienyl cobalt (cobaltene) and biscyclopentadienyl tungsten stainless hydride were used, ammonia was used as a reactive gas, and tungsten wire was used as a metal catalyst.

  When forming the film, a method of sequentially supplying two kinds of organometallic compound raw materials was adopted. Specifically, first, a raw material bottle containing cobaltcene was heated to 50 ° C., and a raw material bottle containing biscyclopentadienyl tungsten stainless hydride was heated to 100 ° C. Thereafter, helium at a flow rate of 30 sccm was vented to each bottle, and the raw material vapor was entrained and conveyed onto the substrate.

  Specifically, cobaltcene is first supplied into the vacuum chamber for 3 seconds. Next, purging with helium at a flow rate of 30 sccm is performed. Thereafter, ammonia at a flow rate of 30 sccm is supplied into the vacuum chamber for 9 seconds. In the meantime, a current of 3 A is applied to the tungsten wire to heat it up red. Then, purging with helium at a flow rate of 30 sccm is performed.

  Thereafter, biscyclopentadienyl tungsten stainless hydride is supplied into the vacuum chamber for 3 seconds. Next, purging with helium at a flow rate of 30 sccm is performed. Thereafter, ammonia at a flow rate of 30 sccm is supplied into the vacuum chamber for 9 seconds. In the meantime, a current of 3 A is applied to the tungsten wire to heat it up red. Then, purging with helium at a flow rate of 30 sccm is performed.

  The above process as one cycle, as shown in FIG. 4, supply of cobaltcene, purge, supply and energization of ammonia, purge, supply of biscyclopentadienyl tungsten stainless hydride, purge, supply and energization of ammonia, The purge was repeated.

  As a result, in Example 7, the film forming speed was 0.04 nm / cycle, and the resistivity was 25 μΩcm. Further, after the film formation, the composition of the metal thin film obtained by X-ray photoelectron spectroscopy (XPS) was examined. As a result, the cobalt composition was 90%, the tungsten composition was 10%, and carbon, oxygen, and nitrogen were both lower detection limits. % Or less.

(Comparative Example 1)
In Comparative Example 1, an experiment by a thermal CVD method was performed. Specifically, as shown in Table 4, the substrate was kept at 400 ° C., and the pressure in the vacuum chamber was kept at 3.99 × 10 ² Pa (= 3 Torr) using an automatic pressure controller (APC).
The raw material bottle containing cobaltcene was heated to 50 ° C., and the raw material vapor was entrained by helium at a flow rate of 30 sccm and supplied into the vacuum chamber. At the same time, hydrogen gas was supplied into the vacuum chamber at a flow rate of 30 sccm.
As a result, as shown in Table 5, the metal thin film was not formed even when supplied for 60 minutes.

(Comparative Example 2)
As shown in Table 4, an experiment was performed under the same conditions as in Comparative Example 1 except that ammonia was used instead of hydrogen gas.
As a result, as shown in Table 5, the metal thin film was not formed even when supplied for 60 minutes.

(Comparative Example 3)
In Comparative Example 3, an experiment by PECVD was performed. Specifically, as shown in Table 4, the substrate was kept at 300 ° C., and the pressure in the vacuum chamber was kept at 3.99 × 10 ² Pa (= 3 Torr) using an automatic pressure controller (APC).
The raw material bottle containing cobaltcene was heated to 50 ° C., and the raw material vapor was entrained by helium at a flow rate of 30 sccm and supplied into the vacuum chamber. At the same time, hydrogen gas was supplied into the vacuum chamber at a flow rate of 30 sccm.
At the same time, 150 W RF was applied using the shower head and the substrate stage (mounting table) as electrodes to generate capacitively coupled plasma.

  As a result, as shown in Table 5, the film forming speed was 2 nm / min, and the resistivity was 250 μΩcm. Further, after the film formation, the composition of the metal thin film obtained by X-ray photoelectron spectroscopy (XPS) was examined. As a result, both oxygen and nitrogen were 1% or less, which is the lower detection limit, but 35% carbon was contained. It was.

(Comparative Example 4)
In Comparative Example 4, an experiment by the PEALD method was performed. Specifically, as shown in Table 4, the substrate was kept at 250 to 350 ° C., and the pressure in the vacuum chamber was kept at 2.66 Pa (= 0.02 Torr) using an automatic pressure controller (APC).
Then, the raw material bottle containing cobaltcene is heated to 50 ° C., and the raw material vapor is accompanied by helium at a flow rate of 30 sccm and supplied into the vacuum chamber for 3 seconds. Next, purging with helium at a flow rate of 30 sccm is performed.
Thereafter, ammonia at a flow rate of 30 sccm is supplied into the vacuum chamber for 6 seconds. Meanwhile, inductively coupled plasma was generated at the ammonia supply port. Then, purging with helium at a flow rate of 30 sccm is performed.
The above steps were set as one cycle, and the material supply, purge, ammonia supply, plasma generation, and purge were repeated.

  As a result, as shown in Table 5, the film formation rate was 0.01 nm / cycle, and the resistivity was 50 μΩcm. Further, after the film formation, the composition of the metal thin film obtained by X-ray photoelectron spectroscopy (XPS) was examined. As a result, oxygen was 1% or less, which is the lower limit of detection, but carbon was 4% and nitrogen was 10%. It was included.

(Comparative Example 5)
In Comparative Example 5, the experiment was performed in substantially the same manner as in Example 1. As shown in Table 4, the pressure in the vacuum chamber was set to 2.66 × 10 ² Pa (= 2 Torr). The other conditions were the same as in Example 1 to form a metal thin film.
As a result, no metal thin film was formed as shown in Table 5.

  The present invention can be widely used in manufacturing industries that manufacture products using metal thin films.

DESCRIPTION OF SYMBOLS 1 ... Film forming apparatus, 2 ... Vacuum chamber, 3 ... Raw material conveyance means, 4 ... Reactive gas conveyance means, 5 ... Mounting stand, 6 ... Substrate, 7 ... Exhaust pump, 8 ... metal catalyst body, 9 ... power source, 10 ... gas ejection part, 11 ... raw material supply source, 12, 14, 16, 18, 22, 24 ... piping, 13 , 15, 23, 25 ... valve, 17 ... raw material reservoir, 21 ... reactive gas supply source, 26 ... shower head

Claims (13)

A raw material transporting step for transporting an organometallic compound raw material onto a film forming object placed in a vacuum chamber;
A reactive gas carrying step of bringing the reactive gas into contact with a heated metal catalyst body and then carrying the reactive gas onto the film-forming target placed in the vacuum chamber. A method for forming a thin film.   The organometallic compound raw material or / and the reactive gas is composed of only one or more atoms selected from a carbon atom, a nitrogen atom, a hydrogen atom, a silicon atom, a phosphorus atom, a boron atom and a metal atom. The method for forming a metal thin film according to claim 1. The method for producing a metal thin film according to claim 1 or 2, wherein the organometallic compound raw material contains an organometallic compound represented by the following chemical formula (1).

In the chemical formula (1), M ₁ is any _one of cobalt, nickel, iron, manganese, ruthenium and chromium, and R _{1 to} R ₅ are hydrogen or a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more. is there. The method for producing a metal thin film according to claim 1 or 2, wherein the organometallic compound raw material contains an organometallic compound represented by the following chemical formula (2).

In the chemical formula (2), M ₂ is tungsten, molybdenum, or titanium, and R _{6 to} R ₁₀ are hydrogen or a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more. The method for producing a metal thin film according to claim 1 or 2, wherein the organometallic compound raw material contains an organometallic compound represented by the following chemical formula (3).

In the chemical formula (3), M ₃ is platinum, niobium, zirconium or titanium, R _{11 to} R ₁₅ are hydrogen or a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more, and R _{16 to} R _18. Is a hydrocarbon represented by C _n H _{2n + 1} where n is 1 or more.   6. The reactive gas according to claim 1, wherein the reactive gas contains at least one of ammonia, dimethylhydrazine, methylamine, dimethylamine, silane, disilane, and hydrogen. A method for forming a metal thin film.   The method for forming a metal thin film according to any one of claims 1 to 6, wherein the metal catalyst body contains at least one of tungsten, platinum, rhodium, and ruthenium.   8. The method for forming a metal thin film according to claim 1, wherein the metal catalyst body is heated by energization only during the reactive gas conveying step. 9.   9. The process according to claim 1, further comprising a purge step of alternately removing the raw material transfer step and the reactive gas transfer step, and removing residual gas in the vacuum chamber between the respective steps. A method for forming a metal thin film according to claim 1. 10. The method for forming a metal thin film according to claim 1, wherein, in the reactive gas transfer step, a pressure in the vacuum chamber is set to 1.33 × 10 ² Pa or less. .   11. The metal according to claim 1, wherein in the raw material transporting step, two or more kinds of the organometallic compound raw materials are used and are transported simultaneously or sequentially onto a film forming object. A method for forming a thin film.   A metal thin film formed by the method for forming a metal thin film according to any one of claims 1 to 11. A vacuum chamber in which a film-forming target can be placed inside;
A raw material transport means capable of transporting an organometallic compound raw material onto a film forming object placed in the vacuum chamber;
Reactive gas transport means capable of transporting the reactive gas after contacting the heated metal catalyst body on the film-forming object placed in the vacuum chamber. Film forming equipment.

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