JP2001303252A - Material generating method and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material generating method by which only a material to be generated (for example, a metal copper) can be extracted, and an apparatus thereof. SOLUTION: A gas constituting a main raw material, a gas constituting an auxiliary raw material, a gas constituting a carrying medium, etc., are allowed to flow into a reaction chamber 10 from a raw material feeder 23, and the chemical reaction is generated between the gases in the reaction chamber 10 to form a film (a metal copper layer) on a surface of a substrate W. A chemical species consisting of an element having the atomic weight of at least 4 (for example, argon) in an energy state higher than the ground state is introduced into the reaction chamber 10 from an active species generating apparatus 19. The chemical reaction is generated in the gases by utilizing the energy of the chemical species to form the material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substance producing method for producing a desired substance by causing a chemical reaction of gas mainly in a reaction chamber, and an apparatus therefor.

[0002]

2. Description of the Related Art In the following description, for the sake of simplicity, chemical vapor deposition for forming copper wiring on a semiconductor substrate (hereinafter abbreviated as "CVD" as necessary) will be described as a typical example.

[0003] There is a tendency that demands for higher speed, higher integration, and lower power consumption of LSI operation are increasing. Along with this, miniaturization of a semiconductor wiring structure is rapidly progressing. However, as the wiring portion of the semiconductor becomes finer and higher in density, the transmission line width and the line-to-line distance decrease, the line-to-line capacitance increases, and the current density significantly increases (up to 1 × 10 ⁴ A / c).
m ² or more), resulting in delays in signal transmission and
The increase in the frequency of occurrence of electromigration (EM) is a serious problem.

In order to solve the problems described above, a copper (Cu) system having a low electric resistivity and high electromigration resistance, which is a substitute for the conventional wiring material of aluminum (Al) system, has attracted attention.

[0005] In fact, the electrical resistivity of copper is as small as about 2/3 that of aluminum, and the limiting current density is four times that of the Al-Cu alloy system. Further, there is a report that the former electromigration resistance is improved by three orders of magnitude in terms of room temperature life over the latter.

[0006] However, it is expected that the damascene method of embedding the inside of a fine recess with copper becomes extremely difficult as the wiring width becomes smaller. Judging from the comparison and examination examples of the specific means proposed for the copper damascene method, in the highly integrated semiconductor generation in which the conductive line width is 0.13 μm or less, the wiring is formed by the conventional power supply layer deposition by sputtering and the subsequent electrolysis. It is difficult to perform this by a combination of the fine embedding steps by plating.

Therefore, at least only the power supply layer is formed by the chemical vapor deposition (CVD) method, or the simultaneous embedding without forming the power supply layer is performed by the same chemical vapor deposition method (CV).
The recognition that it is unavoidable to carry out according to D) is becoming established.

In the chemical vapor deposition method, a raw material of an organic complex containing copper is vaporized and sent to a reaction chamber, mixed with another gas, and
It is common practice to decompose the raw material and subsequently deposit copper. Here, since the raw material copper organic complex used in the ordinary method contains a large amount of carbon as a constituent element, the potential disadvantage is that carbon is easily mixed into the copper film due to an inconvenient reaction caused by decomposition of the raw material. There is.

When the carbon is mixed, carbon atoms are interstitial as impurities in the copper crystal lattice, so that a large-scale lattice strain is introduced into the pure copper crystal structure. Accompanying this, the internal stress and the electrical resistivity increase significantly.

The electric resistivity ρ of a metal changes its value depending on the temperature and the impurity content, and can be described by Mathiesen's rule in the following equation (1). ρ = α + βT (1) (α and β are independent of T)

Here, T is the temperature, α is the electric resistivity of the metal at a residual electric resistance caused by impurities or lattice defects = absolute zero degree, and βT is the electric power by phonon scattering when the base metal at the temperature T is in a completely crystalline state. Indicates resistivity.

Β is particularly called a temperature coefficient, and the temperature 2
In the case of copper at 0 ° C., the value of equation (2) is taken with K as the unit of absolute temperature. β = 4.33 × 10 ⁻³ K ⁻¹ (2)

The change in electrical resistivity due to impurities is 1
According to the following function, as the impurity increases, the constant term α in the equation (1) increases in proportion to the concentration.

When copper is deposited by the chemical vapor deposition method, as described above, a large amount of C and O may be mixed into the formed copper film from ligands and adducts, which are constituents of the organic complex raw materials used. Is big.

In fact, it is often reported that the electrical resistivity of a copper thin film immediately after being formed by a chemical vapor deposition method is about 3 μΩcm or more, which is much higher than that of bulk (= 1.7 μΩcm).

As described above, one of the main reasons for using copper instead of aluminum which has been conventionally used as a metal material for semiconductor wiring is to reduce the electrical resistivity. 2.7μΩ resistivity
Showing values higher than cm is out of the question. It is considered that having such a high electrical resistivity is extremely likely to be caused by the fact that impurities such as carbon and oxygen contained in the copper film are larger than an allowable value. Therefore, it is necessary to eliminate the organic components of the precursor precursor and extract only the copper metal portion to be used for film formation.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a method and apparatus for producing a substance capable of extracting only a substance (for example, metallic copper) to be produced. It is in.

[0018]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method in which a gas serving as a main material, a gas serving as an auxiliary material, and a gas serving as a carrier medium are introduced into a reaction chamber, and a gas between the gases is introduced into the reaction chamber. In a substance producing method for producing a desired substance by causing a chemical reaction to occur, a chemical substance comprising a certain amount of atoms having an atomic weight of 4 or more in an energy state higher than the ground state separately from the gas causing the chemical reaction. The method is characterized in that the seed is introduced directly into the reaction chamber or at a predetermined position in a pipeline system connected to the reaction chamber. By using a chemical species that emits only the energy necessary for the substance to be generated as the chemical species (with an energy range in which impurities do not occur), it is attempted to generate the substance without mixing impurities. Only substances (eg metallic copper) can be extracted.

Further, the present invention is characterized in that the generation of a substance by a chemical reaction between gases in the reaction chamber is a film formation on a substrate surface by a chemical vapor deposition method.

Further, according to the present invention, the base material is a semiconductor substrate, the desired substance is copper, and the chemical vapor deposition supplies power to a fine recess provided in the substrate for the purpose of forming copper wiring of the semiconductor. A certain amount of chemical species introduced for depositing a layer or a catalyst layer or for directly filling the micro-dents is an inert gas (He, Ne, Ar, Kr, Xe, Xe).
Rn, etc.).

The present invention also provides a method for applying a microwave, applying heat energy, irradiating an ultraviolet ray or a laser beam, irradiating an electron beam or a charged particle beam, so as to bring the chemical species into an energy state higher than the ground state. At least one of ionizing wave or atomic beam irradiation, application of a magnetic field or electric field, generation of plasma, administration of a high-temperature object or a heating source, application of an elastic wave, or contact with a reaction promoting substance (including a catalyst or the like) Is used to cause dissociation, bonding, excitation or ionization of introduced chemical species.

Further, in the substance generating apparatus according to the present invention, a raw material supply mechanism for supplying a gas as a main raw material, a gas as an auxiliary raw material, and a gas as a carrier medium, and reacts the gas supplied from the raw material supply mechanism. A reaction chamber for supplying a chemical species in a state higher than the ground state directly to the reaction chamber or at a predetermined position of a pipeline system connected to the reaction chamber. .

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, specific conditions will be described after the conditions for separating high-purity copper from a raw material are described. [Conditions for Separating Pure Copper from Raw Material] FIG. 1 is a diagram showing the molecular structure of hexafluoroacetylacetonate / trimethylvinylsilane copper as an example of a raw material employed in the chemical vapor deposition method. The raw material shown in FIG.
In order to form and deposit a u thin film, copper (Cu) is separated from an adduct (tmvs) and a ligand (hfac) to obtain free copper (Cu), and the separated adduct and ligand cause inconvenient decomposition. It is indispensable to completely vaporize and scatter without leaving free carbon (C) and oxygen (O).

Now, considering the strength of the bond inside the molecular structure of FIG. 1, Cu-tmvs is connected by relatively weak energy, and this portion is usually dissociated in the gas phase.
On the other hand, the Cu-ligand (hfac) is connected with a slightly higher binding energy, and the dissociation of this portion occurs on the substrate surface, unlike in the normal gas phase. And (1) the binding energy between Cu and tmvs is 2.34 e
It is considered to be close to V.

On the other hand, it is necessary to prevent at least some C ＝ C bonds and CO bonds from being dissociated in order to avoid the decomposition of the ligands and adducts into the individual atoms constituting them. (2) The binding energy of the portion where carbon is involved corresponds to at least about 4 eV or more.

According to the above (1) and (2), the energy to be applied to cause a desired reaction is at least 2.3.
It can be seen that it is not less than eV and not more than 4 eV. That is, if the energy is less than 2.3 eV, a useful reaction does not occur, and if the energy exceeds 4 eV, an unfavorable reaction occurs. When this energy is converted into the wavelength of light to be irradiated, it is 310 to 5
This corresponds to a range of 17 nm.

[Method of Applying Dissociation Energy] There are several examples of CVD research for obtaining a copper film on a substrate by irradiating and applying energy instead of heat, such as laser, ultraviolet light, or plasma, to a reaction chamber. FIGS. 3 and 4 are diagrams respectively showing examples of a conventional photo-CVD apparatus using ultraviolet light and a high-frequency plasma CVD apparatus which are conventionally used. In the photo-assisted CVD apparatus shown in FIG. 3, a substrate 85 is placed on a susceptor 83 having a heater 81 in a reaction chamber 80, and an ultraviolet light source ( A copper film is formed on the substrate 85 by irradiating light from a mercury lamp (89) and vaporizing from a raw material supply device 91 through a vaporizer 93 and reacting the raw material introduced into the reaction chamber 80 while irradiating the ultraviolet light. Is what you do.

In the high-frequency plasma CVD apparatus shown in FIG. 4, a substrate 85 is placed on a susceptor 83 having a heater 81 in a reaction chamber 80, and is vaporized from a raw material supply device 91 via a vaporization device 93. The substrate 8 is reacted by reacting the raw material ejected from the nozzle 95 in the plasma.
5 is to form a copper film. Reference numeral 97 denotes an RF power supply.

However, when the above method is used, since the copper film obtained as described above contains oxygen and carbon as impurities, the electric resistivity is significantly higher than that of the bulk. There is.

This is mainly due to the decomposition of the ligand and the adduct itself as described above, and as a result, free oxygen and carbon are generated in the gas phase in the reaction chamber and on the surface of the substrate, and these enter the deposited copper film. It is thought to be possible.

The reason why the dissociation of the ligand or the adduct occurs is that the above-mentioned limited energy supply range: 2.3 e
It is possible to point out a possibility of deviating from the condition of not less than V and not more than 4 eV.

In practice, when energy is applied by plasma or ultraviolet light irradiation by discharge, the energy is distributed according to a certain law, so that it is difficult to strictly limit the numerical value.
In the laser irradiation, the energy of a single photon can be limited, but if absorption of two or more photons occurs with a certain probability, the same result as applying more than the limited energy is obtained.

In view of the above situation, the present invention employs a method in which a chemical species in a high energy state is introduced into the system, not in the form of light or plasma, in order to cause a reaction.

[Specific Means for Realizing the Present Invention] FIG. 2 is a schematic view showing a copper CVD apparatus to which an active argon generator according to an embodiment of the present invention is added. As shown in FIG. 1, the copper CVD apparatus has a susceptor 13 having a built-in heater 11 installed in a reaction chamber 10, a substrate W placed on the susceptor 13, and a nozzle 15 installed in the reaction chamber 10. The nozzle 15 is connected to an active argon generator 19 via a transfer pipe 17, and the transfer pipe 17 is connected to a raw material supply device 23 via a vaporizer 21. Note that argon is supplied from the argon storage container 25 to the active argon generator 19.

Next, the operation of this device will be described. First, in the active argon generator 19, a large current discharge plasma is generated inside by applying the generation principle of an argon ion laser, thereby giving excitation / ionization energy to the argon (Ar) gas supplied from the argon storage container 25. I do. Then, Ar atoms or ions having higher energy than the ground state generated here are introduced into the reaction chamber from the transfer pipe 17, and are mixed with the raw material gas on the way.

The gas sufficiently mixed in the nozzle 15 expands in the reaction chamber 10 and causes dissociation of the raw material components and subsequent deposition of copper on the substrate W.

A part of the argon to which energy has been imparted by the discharge in the active argon generator 19 is converted into monovalent argon ions by a reaction represented by the following formula (3).

Embedded image

On the other hand, part of the argon ions of the formula (3) reaching the reaction chamber 10 emits light of a specific wavelength and is reduced by the following formula (4) to return to neutral argon atoms.

Embedded image

As described above, the range of the effective energy E to be applied to the copper source gas according to the principle of the present invention is expressed by the following equation (5). It becomes like 6). 2.3 eV ≦ E ≦ 4.0 eV (5) 310 nm ≦ λ ≦ 517 nm (6)

As is apparent from equations (4) and (6), A
Light emitted upon reduction of r ²⁺ and Ar ⁺ (wavelength 351,
(364, 488, 515 nm), the copper source gas can be effectively dissociated. In addition, as long as the light has a wavelength in the range of the expression (6), the decomposition of the adduct or the ligand itself does not occur, so that the reaction chamber 1
There is no danger of free carbon or oxygen being generated within zero. Therefore, unnecessary impurities can be prevented from entering the obtained deposited film.

By the way, Ar ions generated by application of discharge energy easily lose energy due to collision or adsorption with surrounding particles or metal inner wall surfaces (the wall recombination coefficient is large). To cope with this, the transfer pipe 17 connecting the active argon generator 19 and the reaction chamber 10 is made of fluororesin by experimental verification, and is manufactured to have an inner diameter of 35 mm or more and a length of 70 mm or less. Further, it is an essential manufacturing condition that the surface of the internal gas contact member including the reaction chamber 10 is coated with a fluororesin.

On the other hand, conventionally, at another portion separated from the reaction chamber (main reaction chamber) by a certain distance, active species, such as active atoms, molecules, atomic groups, and ions, which are in an energy state higher than the ground state, are generated, Various systems have been proposed as a system (distantly active species application system) for feeding this into the main reaction chamber and promoting a desired reaction in the main reaction chamber. However, in the conventional system of this kind, any generated active species plays a role of causing a chemical change by participating in a target reaction formula.

On the other hand, the active species used in the present invention does not become a chemical species in the reaction formula itself, but plays a role only as a medium for transmitting energy necessary for causing a reaction. The configuration is very different.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims and the technical idea described in the specification and the drawings. Is possible. Even if not directly described in the specification and the drawings, it is within the scope of the technical idea of the present invention as long as the functions and effects of the present invention are achieved.

That is, for example, in the above-described embodiment, an example is shown in which the present invention is applied to chemical vapor deposition for forming copper wiring on a semiconductor substrate. However, the present invention may be applied to other various substance generation methods. The point is that a gas as a main material, a gas as an auxiliary material, a gas as a carrier medium, and the like flow into the reaction chamber, and a chemical reaction is caused between the gases in the reaction chamber to produce a desired substance. Then, the present invention can be applied.

In the above embodiment, a large-current discharge plasma is generated in order to bring the chemical species into an energy state higher than the ground state. However, the energy state may be increased by other various methods. That is, application of microwaves, application of thermal energy, irradiation of ultraviolet rays or laser beams, irradiation of electron beams or charged particle beams, irradiation of ionizing waves or atomic beams, application of magnetic fields or electric fields, generation of plasma, high-temperature objects or heating Any substance can be used as long as it causes dissociation, binding, excitation, or ionization of chemical species using at least one of administration of a source, application of an elastic wave, and contact with a reaction promoting substance (including a catalyst or the like).

[0047]

As described above in detail, according to the present invention, there is an excellent effect that only the substance to be formed (eg, metallic copper) can be extracted without mixing impurities.

[Brief description of the drawings]

FIG. 1 is a diagram showing a molecular structure of hexafluoroacetylacetonate / trimethylvinylsilane copper as an example of a raw material employed in a chemical vapor deposition method.

FIG. 2 is a schematic view showing a copper CVD apparatus to which an active argon generator according to one embodiment of the present invention is added.

FIG. 3 is a schematic view showing an example of a conventional photo-CVD apparatus using ultraviolet light.

FIG. 4 is a schematic view showing an example of a conventional high-frequency plasma CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Reaction chamber 11 Heater 13 Susceptor W Substrate (substrate) 15 Nozzle 17 Transfer pipe 19 Active argon generator (chemical species supply means) 21 Vaporizer (raw material supply mechanism) 23 Raw material supply apparatus (raw material supply mechanism) 25 Argon storage container (Chemical species supply means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuji Araki 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation 4K030 AA16 BA01 CA04 CA12 EA03 FA01 FA07 FA08 FA10 FA12 FA14 FA15 4M104 BB04 CC01 DD44 DD45 HH16

Claims (5)

[Claims] 1. A substance that flows into a reaction chamber as a main raw material, a gas as an auxiliary raw material, and a gas as a carrier medium, and generates a desired substance by causing a chemical reaction between the gases in the reaction chamber. In the production method, aside from the gas that causes the chemical reaction, a chemical species composed of an element having an atomic weight of 4 or more in an energy state higher than the ground state is directly in the reaction chamber or a pipe system connected to the reaction chamber. A method for producing a substance, wherein the substance is introduced into a predetermined location. 2. The method for producing a substance according to claim 1, wherein the substance production by a chemical reaction between gases in the reaction chamber is a film formation on a substrate surface by a chemical vapor deposition method. 3. The method according to claim 1, wherein the base material is a semiconductor substrate, the desired material is copper, and the chemical vapor deposition is a power supply layer or a catalyst formed in a fine recess formed in the substrate for the purpose of forming copper wiring of the semiconductor. A certain amount of chemical species introduced for depositing a layer or for directly filling the micro-dents is at least one of inert gases (He, Ne, Ar, Kr, Xe, Rn, etc.). 3. The method for producing a substance according to claim 2, wherein the substance originates from: 4. Applying a microwave, applying heat energy, irradiating an ultraviolet ray or a laser beam, irradiating an electron beam or a charged particle beam, ionizing wave, Or atomic beam irradiation,
Dissociation of introduced species using at least one of application of a magnetic field or an electric field, generation of plasma, administration of a high-temperature object or a heating source, application of elastic waves or contact with a reaction promoting substance (including a catalyst or the like), The method for producing a substance according to claim 1, wherein binding, excitation or ionization is caused. 5. A source supply mechanism for supplying a gas serving as a main material, a gas serving as an auxiliary material, and a gas serving as a transport medium, and a reaction chamber for reacting the gas supplied from the material supply mechanism. A substance producing apparatus, characterized in that chemical substance supply means for supplying a chemical species in a state higher than a ground state is provided at a predetermined position of a pipe system directly to the reaction chamber or connected to the reaction chamber.