JP2002146535A - Zirconium nitride thin film, method and apparatus for producing the thin film, and method and apparatus for forming copper wiring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for depositing a zirconium nitride thin film having a specific resistance value close to that of the bulk material and usable, e.g. as a barrier film for preventing diffusion in an electronic device by a CVD process, and to provide a method and apparatus for forming copper wiring. SOLUTION: In the method and apparatus for producing a zirconium nitride thin film by a CVD process, tetrakisdialkylaminozirconium(TDAAZ) and a reaction gas (gaseous NH3) reacted therewith are fed into a reaction vessel. The total pressure (Pa) is controlled to 1 to 1,500. The flow rate (g/min) of the liquid TDAAZ is controlled to 0.001 to 0.1, the flow rate (l/min) of the gaseous NH3 is controlled to 0.1 to 5, the ratio of the flow rate (g/min) of the liquid TDAAZ to the flow rate (ml/min) of the gaseous NH3, i.e., TDAAZ/NH3 is controlled to 2×10-7<=TDAAZ/NH3 (g/ml) <=2×10-4, and the temperature ( deg.C) of a substrate is controlled to 300 to 450. In this way, the zirconium nitride thin film is produced on the surface of the substrate. The zirconium thin film produced thereby has a composition of, by molar ratio, zirconium: nitrogen is 1:1 to 1:1.25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing a zirconium nitride thin film for forming a zirconium nitride thin film on a substrate to be processed by a CVD method. Further, the present invention relates to a copper wiring forming method and a copper wiring forming apparatus, wherein a copper thin film is formed on an insulating film formed on a substrate to be processed and provided with a concave portion, and the concave portion is filled with a copper material.

[0002]

2. Description of the Related Art Zirconium is nitrided to form cubic ZrN. This phase is very hard, has a high melting point, is chemically stable, and is resistant to organic solvents and inorganic acids. It is also characterized by superconductivity at low temperatures. Therefore, the nitride thin film has many possibilities for the application. For example, reducing tool wear,
There are also applications for friction reducing coatings and golden decorations. Utilizing its optical characteristics, it is also used for an optical film for wavelength selection and a solar control coating for windows.

In the field of microelectronics, zirconium nitride films are also used as gate materials, Josephson junction devices, superconductors, low-temperature thermometers, and low-resistance contacts.
It has also been proposed to use as an anti-diffusion barrier in an interconnected metallization scheme, a gate electrode of a MOS transistor, or a low-barrier Schottky diode, and its use is diversified.

[0004] As a method for producing a zirconium nitride thin film, there are a sputtering method, a reactive sputtering method, an ion plate method, an electron beam evaporation method, a thermal CVD method, and the like. Film formation methods have been selected.

In such a thin film manufacturing process, an object on which a thin film is manufactured (referred to as a “substrate” in this specification) is often flat, but fine holes or grooves formed on the surface are often formed. In many cases, a thin film is formed inside a concave portion such as the above.

For example, FIG. 9 shows a schematic view of an arbitrary part of an electronic device. In the form of the electronic device shown in FIG. 9, an insulating layer 2 provided with a recess 3 is formed on a substrate 1 such as a Si wafer, and a barrier layer 4 is formed on an inner surface of the recess 3 to form a barrier layer. For example, a wiring member 5 such as copper is buried in the interior covered with 4.

In various semiconductor devices, a structure in which a wiring material such as tungsten is embedded in a contact hole is employed as a structure of a contact portion. in this case,
In order to prevent the interdiffusion between the contact wiring and the underlying semiconductor layer, a thin barrier film is interposed between the two. That is, it is necessary to form a barrier film on the inner surface of the concave portion of the contact hole.

Further, in logic integrated circuits, copper is often used as a wiring material in order to enable higher-speed operation. However, this copper is also easily diffused into silicon or a silicon oxide insulating layer. Also, it is necessary to prevent diffusion by interposing a barrier film.

Further, with respect to the technique of burying wiring in an interlayer through hole, which is often used in a device structure having a multilayer wiring structure, it is necessary to form a thin film on the inner surface of the concave portion. For example, by embedding copper in the interlayer through hole,
In the case of forming an interlayer wiring, a barrier layer is interposed between them, that is, on the inner surface of the interlayer through hole, in order to improve barrier properties between the buried copper and the surface forming the interface.

As described above, in microelectronic components mainly for semiconductor devices, these thin films have been conventionally formed by chemical vapor deposition (CVD) and physical vapor deposition (PVD) techniques. Above all, the CVD method has many advantages as compared with the PVD method. It is generally excellent in coverage (step coverage, bottom coverage, etc.) on the inner surface of a concave portion such as a fine hole or groove formed on the surface of a substrate, as in the above-described semiconductor device requiring a higher degree of integration. Growth rate, organizational control,
This is because the fineness of the structure is also excellent.

From such a background, a technique for producing a zirconium nitride thin film by a CVD method (chemical vapor deposition method) has recently attracted attention.

The inventor of the present invention has proposed a base film, a barrier film, and an adhesion layer film for a copper wiring for a semiconductor device: a barrier film and / or an adhesion layer film for a tungsten or aluminum wiring: a barrier film and / or an adhesion layer for a metal gate. Film: A method of forming a zirconium nitride thin film suitable for a barrier film and / or an adhesion layer film between a high dielectric substance and an electrode by a thermal CVD method has been studied.

To prepare a zirconium nitride thin film by a CVD method, various methods and source gases have been proposed by many people so far. As one of them, a technique using tetrakisdialkylaminozirconium (hereinafter abbreviated as TDAAZ), which is a kind of organometallic compound, as a raw material gas has attracted attention. The chemical structural formula of this TDAAZ is shown in FIG.
Shown in In this chemical formula, R is an alkyl group. One in which R is limited to an ethyl group is tetrakisdiethylaminozirconium (hereinafter abbreviated as TDEAZ).

TDEAZ is a liquid at room temperature and atmospheric pressure, has good evaporability, and has excellent thermal stability.
It is easy to handle and has many advantages such as having a saturated vapor pressure of 13 Pa at 385K. Moreover, since nitrogen is sigma-bonded, formation of ZrN is easy.

Zr which is considered as another candidate of the source gas
Cl ₄ , like Zr [N (C ₂ H ₅ ) ₂ ] ₄ , contains a zirconium metal atom and has a high evaporability, but TDAAZ.
It is less reactive and more likely to cause chlorine contamination in the membrane, requiring special care since chlorine contamination is known to degrade the mechanical performance of the membrane.
When N ₂ / H ₂ and ZrCl ₄ are used, 1000
It is also a problem that a high temperature exceeding ℃ is required.

When an organic zirconium compound such as TDAAZ is used as a liquid raw material, it is vaporized and then supplied to a reaction vessel through a shower head together with a carrier gas such as H ₂ , Ar, or N ₂ . Is common. It is also necessary to supply an additional gas (for example, ammonia gas) that chemically reacts with the organic zirconium compound into the reaction vessel. There is a substrate in the reaction vessel, and this substrate is kept at a predetermined reaction temperature.

When the organic zirconium compound and the additional gas are supplied, a reaction of forming zirconium nitride occurs, and a zirconium nitride (ZrN) film is deposited on the substrate. In this case, it is known that the electrical characteristics and the step coverage of the deposited zirconium nitride film depend on the flow rate of the organic zirconium compound reacting in the reaction vessel and the additive gas, the substrate temperature and the reaction pressure.

For example, Harverd's Renand et al.
ater1991 `` chemical vaper deposition of titanium, zir
conium, and hafnium nitride thin films ''
It is reported that a zirconium nitride thin film was formed on a substrate of silicon, low soda glass, stainless steel, etc. by chemical vapor deposition under atmospheric pressure using a compound of a tetrakisdialkylamide metal and ammonia. However, the formed thin film was crystalline, yellow and transparent Zr ₃ N ₄ , and was rich in nitrogen. The specific resistance of the film formed on the glass substrate was 10 ⁶ μΩ. cm (more than 100 kΩ / square in terms of sheet resistance), it was almost close to an insulator.

H. Wendel et al., Appl. Phys. A54, 389-39.
2 (1992) `` Thin Zirconium Nitride Films Prepared by P
lasma-Enhanced CVD ”, using tetrakisdiethylaminozirconium (TDEAZ) as a precursor and hydrogen as a reaction gas, and having a specific resistance of 1000 μΩ · cm.
Of ZrN film. However, this was manufactured using plasma, and in this case, impurities remained and the specific resistance value was 1000 μΩ · cm as described above.
Not less.

Therefore, the CVD method has been evaluated as being excellent in coverage such as bottom coverage and step coverage. However, in the case of a zirconium nitride film,
Problems to be solved as described above remain.

[0021]

SUMMARY OF THE INVENTION Thin films for diffusion barriers as gate materials, Josephson junction devices, superconductors, low temperature thermometers, low resistance contacts, and in interconnected metallization schemes have low resistance ( It is desirable to produce a thin film as close to the bulk as possible.

However, the thin film formed by using the conventional technique developed by Renand et al. Of Harverd University was crystalline, yellow and transparent Zr ₃ N ₄ and was a nitrogen-rich film. The specific resistance of the film formed on the glass substrate is 10 ⁶ μm.
Ω. cm (100k when converted to sheet resistance)
It becomes larger than Ω / square. ), And almost an insulator.

For this reason, a thin film formed by using the conventional technique developed by Renand et al. Of Harverd University is used as a low-resistance contact in the microelectronics field as a diffusion prevention barrier in an interconnected metallization scheme. It was difficult to use as a tool.

In the prior art such as H. Wendel, since plasma is used, impurities remain in the formed film, and the specific resistance value does not become 1000 μΩ · cm or less.

That is, according to the present invention, a zirconium nitride thin film which has a specific resistance value close to that of a bulk and can be used as a thin film for a diffusion prevention barrier in electronic devices mainly for semiconductor devices is miniaturized. It is an object of the present invention to propose a method and an apparatus for producing a zirconium nitride thin film which can be formed by a CVD method so that step coverage for fine wiring grooves and holes corresponding to the above can be improved.

The present invention also relates to a method of forming a copper wiring on a substrate, forming a copper thin film on an insulating film provided with a concave portion, and filling the concave portion with a copper material. It is an object of the present invention to provide a method and an apparatus for forming a copper wiring using a zirconium nitride thin film to be used.

[0027]

In order to achieve the above object,
The zirconium nitride thin film proposed by the present invention is a zirconium nitride thin film prepared by a CVD method using tetrakisdialkylaminozirconium (TDAAZ) as a raw material, and has a composition in a molar ratio of zirconium: nitrogen = 1: 1 to 1: 1.25. It is characterized by being.

Another zirconium nitride thin film is prepared by a CVD method using tetrakisdialkylaminozirconium (TDAAZ) as a raw material, and has a composition of zirconium: nitrogen = 1: 1 to 1: 1.25 in molar ratio. Is subjected to a plasma treatment.

In order to achieve the above object, a method of producing a zirconium nitride thin film proposed by the present invention is a method of producing zirconium nitride by thermal CVD using tetrakisdialkylaminozirconium (TDAAZ) and an ammonia gas reacting therewith. A thin film is deposited on a substrate, and a film forming pressure, a film forming temperature, and a raw material gas (T
The main feature is that the flow rate of DAAZ) and the flow rate of added ammonia gas are clarified.

In other words, the method for producing a zirconium nitride thin film proposed by the present invention is to supply tetrakisdialkylaminozirconium (TDAAZ) and ammonia (NH ₃ ) as an additional gas reacting therewith into a reaction vessel. 1 ≦ total pressure (Pa) ≦ 1500 0.001 ≦ TDAAZ liquid flow rate (g / min) ≦ 0.
1 0.1 ≦ NH ₃ gas flow rate (l / min) ≦ 5 The ratio (TDAAZ / NH ₃ ) of TDAAZ liquid flow rate (g / min) to NH ₃ gas flow rate (ml / min) is 2 × 10 ⁻⁷ ≦ TDAAZ / NH ₃ (g / ml) ≦ 2 ×
At a temperature of 10 ⁻⁴ 300 ≦ substrate temperature (° C.) ≦ 450, a zirconium nitride thin film is formed on the surface of the substrate by a CVD method.

Here, TDAAZ flow rate (g / min)
Is in the liquid state and the NH ₃ flow rate (ml / mi
n) is in the gaseous state.

The inventor has proposed that tetrakisdialkylaminozirconium (TDAAZ), especially tetrakisdiethylaminozirconium (TD), is used as a liquid raw material.
EAZ), ammonia as an additive gas, and nitrogen gas as a carrier gas, the substrate temperature, pressure, tetrakisdiethylaminozirconium (T
The relationship between DEAZ) and the flow rate of ammonia was studied.
Hereinafter, the flow rates of TDAAZ and TDEAZ indicate values in liquid.

The apparatus configuration used will be described in more detail in the examples, but the flow rates of TDAAZ and ammonia gas can be adjusted by respective flow controllers. Also, TDAAZ
The flow rate of ammonia gas can be adjusted by a dedicated flow controller for N _{2 as} a carrier gas.
The carrier gas does not contribute to the chemical reaction of TDAAZ, and in any case, it is optimal to use nitrogen gas. However, it is also possible to use other, a rare gas such as Ar, H ₂ gas and the like.

The ranges of the film forming pressure, the film forming temperature, the flow rate of the raw material gas (TDAAZ) supplied to the reaction vessel, and the flow rate of the added ammonia gas determined by the research of the present inventors are as follows. Is limited by

When the total pressure of the reaction vessel is 1 Pa or more,
The film formation rate (DR) can be set to 1 nm / min or more, thereby improving the film formation efficiency. When the film formation rate (DR) is set to 1500 Pa or less, a cycle (maintenance cycle) in which maintenance must be performed for exhaust gas treatment or the like is lengthened. be able to.

FIG. 4 shows that the substrate temperature was set to 380 ° C., tetrakisdiethylaminozirconium (TDEAZ) was 0.01 g / min, and ammonia gas was 3.0 ml / m 2.
5 is a graph showing the specific resistance value of a ZrN thin film in the case of producing a ZrN thin film by flowing in in relation to a film forming pressure. As is clear from FIG. 4, the total pressure is 0 Pa to 120 P.
It has been confirmed that in the area a, the specific resistance value shows a minimum value near 40 Pa.

The TDAAZ flow rate related to the deposition rate (DR) is set to 0.001 (g / min) or more and 0.1 (g / mi).
n) or less because the TDAAZ flow rate was 0.001 (g
/ Min) or more, the deposition rate (DR) is 1 nm /
min or more, the film forming efficiency is improved,
If it is set to 0.1 (g / min) or less, the formed Z
This is because the specific resistance of the rN thin film can be suppressed to less than 3000 μΩ · cm.

FIG. 5 shows that the pressure of the reaction vessel was fixed at 4 Pa and the flow rate of ammonia was fixed at 5 or 3 ml / min.
FIG. 4 is a graph in which a specific resistance value in a case where a thin film is manufactured is related to a wafer temperature. As parameters, tetrakisdiethylaminozirconium (TDEA)
The flow rate of Z) is taken. As is clear from FIG. 5, when the film is formed at the same wafer temperature (the flow rate of NH ₃ is also the same), it can be confirmed that the specific resistance value tends to increase as the flow rate of TDEAZ increases. The tendency of the resistance value to fall is also supported.

The NH ₃ flow rate was set to 0.1 (l / mi)
n) or more, the specific resistance value of the formed ZrN thin film can be suppressed to less than 3000 μΩ · cm, and 5 (l
/ Min) or less, the maintenance cycle can be lengthened.

FIG. 6 shows the ammonia flow rate when a ZrN thin film was prepared by fixing the pressure of the reaction vessel at 4 Pa, the substrate temperature at 400 ° C., and the flow rate of tetrakisdiethylaminozirconium (TDEAZ) at 0.01 g / min. It is a semi-logarithmic graph of the relationship between the specific resistance values. From FIG. 6, it is confirmed that the specific resistance value tends to increase as the ammonia flow rate decreases.

Further, N of the TDAAZ flow rate (g / min)
The ratio (TDAAZ / N) to the H ₃ flow rate (ml / min)
H ₃ ) is calculated as 2 × 10 ⁻⁷ ≦ TDAAZ / NH ₃ (g / m
l) ≦ 2 × 10 ⁻⁴ is defined as TDAAZ / NH
_{When 3} (g / ml) is smaller than 2 × 10 ⁻⁷ , the film forming rate affecting the throughput becomes 1 nm / min or less, and when it becomes larger than 2 × 10 ⁻⁴ ,
This is because the specific resistance becomes larger than 3000 μΩ · cm.

Further, when the substrate temperature is 300 (° C.) or more,
The reason why the specific resistance value of the formed ZrN thin film is set to 3000 when the substrate temperature is set to 300 (° C.) or more is set to 0 (° C.) or less.
This is because it is possible to keep the resistance lower than μΩ · cm, and if the temperature is set to 450 (° C.) or less, the damage to the wiring of the electronic device can be kept smaller.

In the above-described method for producing a zirconium nitride thin film, tetrakisdialkylaminozirconium (TDEAZ) can be used as the tetrakisdialkylaminozirconium (TDAAZ).

The zirconium nitride thin film of the present invention produced by the method of producing a zirconium nitride thin film of the present invention has a composition of zirconium: nitrogen = 1: 1 to 1: 1.25 (ie, ZrNx (x = 1-1.2
5)), which shows a resistivity value close to that of bulk.

If the composition exceeds zirconium: nitrogen = 1: 1.25 in molar ratio, a high specific resistance is exhibited, and the composition is used as an electronic device, particularly as a barrier film of an electronic device in which a Cu wiring film is formed. It is not preferable in achieving the object of providing a possible zirconium nitride thin film.

The method for producing a zirconium nitride thin film proposed by the present invention comprises a reaction vessel capable of vacuum evacuation, an exhaust device for exhausting the inside of the reaction vessel, and a gas for introducing a reaction gas into the reaction vessel. A supply device, a substrate holder for holding a substrate on which a zirconium nitride thin film is to be deposited, and a heating device for heating the substrate, wherein the inside of the reaction vessel is in a range of 1 ≦ total pressure (Pa) ≦ 1500. A pressure control mechanism capable of maintaining pressure, and a temperature at which the substrate is heated to 3
A temperature control mechanism capable of maintaining the temperature in a range of 00 ≦ substrate temperature (° C.) ≦ 450, and the gas supply device includes:
A source gas introduction system for supplying TDAAZ gas, which is a source gas, and an additive gas introduction system for supplying ammonia gas, which is an additive gas reacting therewith, are configured. The source gas introduction system and the additive gas introduction system are , TDAAZ gas flow rate and ammonia gas flow rate, 0.001 ≦ TDA
AZ liquid flow rate (g / min) ≦ 0.1, 0.1 ≦ NH ₃
Gas flow rate (l / min) ≦ 5, TDAAZ liquid flow rate (g
/ Min) to the NH ₃ gas flow rate (ml / min) (TDAAZ / NH ₃ ) is 2 × 10 ⁻⁷ ≦ TDAAZ
/ NH ₃ (g / ml) ≦ 2 × 10 ⁻⁴ It can be realized by a zirconium nitride thin film manufacturing apparatus characterized by having a flow rate control mechanism for controlling the relation to be satisfied.

Next, the copper wiring forming method proposed by the present invention is as follows.
In the copper wiring forming method of forming a copper thin film on an insulating film formed on a substrate and provided with a concave portion and filling the concave portion with a copper material, ZrNx (x =
1 to 1.25), wherein a step of preparing a zirconium nitride thin film using a tetrakisdialkylaminozirconium (TDAAZ) as a raw material by a CVD method is performed.

Here, ZrNx (x = 1)
The production of a zirconium nitride thin film using tetrakisdialkylaminozirconium (TDAAZ) having a composition of 1.25) as a raw material can be realized by the above-described method for producing a zirconium nitride thin film of the present invention.

The zirconium nitride thin film formed by the method of the present invention is manufactured by the CVD method as described above, has good step coverage to fine wiring grooves and holes, and has the bulk . Therefore, in forming a wiring Cu film having a small specific resistance value, high electromigration resistance, and capable of exhibiting good step coverage by being manufactured by the CVD method, for example, a Cu semiconductor and / or Alternatively, when a zirconium nitride thin film formed by the method of the present invention is used as a barrier film for preventing diffusion into an insulator, it is required for an electronic device mainly formed of a semiconductor device, in which a Cu film for wiring is formed. It is possible to sufficiently cope with miniaturization and high-speed operation.

Another copper wiring forming method proposed by the present invention is as follows.
In the above-described copper wiring forming method of the present invention, before forming the copper thin film, the Zr formed by the CVD method of the present invention is used.
A plasma treatment is performed on a zirconium nitride thin film made of tetrakisdialkylaminozirconium (TDAAZ) having a composition of Nx (x = 1 to 1.25).

A zirconium nitride thin film having a molar ratio of zirconium: nitrogen = 1: 1 to 1: 1.25, prepared by the above-mentioned method of the present invention by a CVD method using tetrakisdialkylaminozirconium (TDAAZ) as a raw material. Has a specific resistance value close to that of bulk, as described above, but can be further improved to a zirconium nitride thin film having a lower sheet resistance value by adding a plasma treatment.

Still another copper wiring forming method proposed by the present invention is the same as the above-described copper wiring forming method, except that tetrakisdialkylaminozirconium (TDAAZ) having a composition of ZrNx (x = 1 to 1.25) by a CVD method is used as a raw material. The formation of a copper thin film subsequent to the production of the zirconium nitride thin film to be formed, or the formation of the copper thin film subsequent to the plasma treatment of the zirconium nitride thin film is sequentially and continuously performed in a vacuum,
The zirconium nitride thin film or the plasma-treated zirconium nitride thin film, without being exposed to the air,
The step of forming the copper thin film is performed while maintaining a vacuum state.

According to this method, it is possible to prevent deterioration of the surface of the zirconium nitride thin film due to exposure to the atmosphere, and to form a Cu wiring film having a good interface without forming an oxide layer between the zirconium nitride thin film and the zirconium nitride thin film. Can be formed.

In the copper wiring forming method proposed by the present invention, the above-described zirconium nitride thin film forming apparatus of the present invention and a film forming apparatus for forming a Cu film for wiring are connected with a vacuum-connected connection structure. A wiring film is formed by a film forming apparatus for forming a wiring Cu film without exposing the substrate on which the zirconium nitride thin film has been formed by the above-mentioned zirconium nitride thin film forming apparatus to the atmosphere and keeping a vacuum state. It can be realized by a copper wiring forming apparatus characterized in that a film is formed.

[0055]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a configuration diagram in the case where a CVD apparatus is employed as an example of a zirconium nitride thin film manufacturing apparatus in which the method of the present invention is performed. A substrate holder 18 is provided inside the reaction vessel 10 provided in this apparatus.
Attach. A zirconium nitride thin film is formed on the surface of the substrate 20. A shower head 54 for introducing gas is provided so as to face the substrate holder 18, and through this shower head 54, a source gas can be introduced from the source gas introduction system 22 and an additive gas is introduced from the additive gas introduction system 24. it can.

The reaction vessel 10 is made of aluminum and can be evacuated by the exhaust system 12 to keep the inside airtight. The exhaust system 12 includes a turbo molecular pump 26
And a dry pump 28 and a pressure control valve 27. The dry pump 28 is made of V
060F dry pump, pumping speed is 1000l
/ Min.

As vacuum gauges for measuring the pressure in the reaction vessel 10, there are a first vacuum gauge 14 for low vacuum and a second vacuum gauge 16 for high vacuum. The first vacuum gauge 14 is a high-precision diagram vacuum gauge having a pressure measurement range of 0.1 Pa to 133 Pa. In this embodiment, Baraktron TYPE128A manufactured by MKS is used. The second vacuum gauge 16 includes:
This is an ionization vacuum gauge having a pressure measurement range of 10 ⁻² Pa to 10 ⁻⁶ Pa. In this embodiment, a BA gauge UGD-1S manufactured by Anelva is used.

The evacuation system 12 can evacuate the interior of the reaction vessel 10 to a pressure of 10 ⁻⁴ Pa and maintain the interior of the reaction vessel 10 at a desired pressure. Device), the first
Vacuum gauge 14, second vacuum gauge 16 for high vacuum, and exhaust system 1
2, the pressure in the reaction vessel 10 is 1 Pa or more,
A pressure control mechanism capable of maintaining the pressure at 1500 Pa or less is configured.

The substrate holder 18 has a substrate heating device 30 for heating the substrate 20. The substrate heating device 30 includes a thermocouple 32 for measuring the temperature of the substrate 20, a heater 34, and a heating power supply 35. Heating power supply 35
Performs PID control of the substrate temperature (or other control methods such as PI control, ON-OFF control, and fuzzy control) based on the measured temperature value.

With this, the temperature of the substrate 20 can be controlled. In the apparatus for producing a zirconium nitride thin film (CVD apparatus) of the present invention, the thermocouple 32 and the heater 3 are used.
4. A temperature control mechanism capable of maintaining the temperature of the substrate 20 in the range of 300 ° C. or more and 450 ° C. or less by the substrate heating device 30 including the heating power supply 35.

The source gas introduction system 22 is provided with a liquid source T
Raw material container 36 containing DAAZ and liquid TDAAZ
, A first flow controller 40 for controlling the flow rate of liquid TDAAZ, a gas cylinder 42 containing a carrier gas for TDAAZ gas, and a flow controller 44 for controlling the flow rate of the carrier gas. It is composed of The vaporizer 38 is a Lintec VU-104, and does not perform bubbling. Vaporized TDAAZ
Is supplied to the shower head 54 via the supply path 76 after being mixed with the carrier gas.

The additive gas introduction system 24 includes an additive gas cylinder 46 containing an additive gas (ammonia gas), a flow controller 48 for controlling the flow rate of the additive gas, and a gas cylinder 50 containing a carrier gas for the additive gas. And a fourth flow controller 52 for controlling the flow rate of the carrier gas. The additive gas is mixed with the carrier gas and supplied to the supply path 7.
8, and is supplied to the shower head 54.

The flow rate of the source gas supplied into the reaction vessel 10 is controlled by the source gas introduction system 22 described above.
Further, the flow rate of the additive gas (for example, NH ₃ gas) supplied into the reaction vessel 10 is controlled by the additive gas introduction system 24, but the zirconium nitride thin film production apparatus (C
VD apparatus), a first flow controller 40 for controlling the flow rate of the liquid TDAAZ and a flow controller 44 for controlling the flow rate of the carrier gas, the first flow control for controlling the flow rate of the liquid TDAAZ. From the reactor 40 to the reaction vessel 10
The liquid flow rate of the raw material gas supplied into the chamber is 0.001 g / m
and a fourth flow controller 52 that controls the flow rate of the carrier gas and the flow rate controller 48 that controls the flow rate of the additive gas, is maintained in a range of not less than in and not more than 0.1 g / min.
The flow rate of the additive gas supplied into the reaction vessel 10 is 0.1 l
/ Min and 5 l / min or less, and the flow rate controllers 40, 44, 48 and 52 further control the ratio of the TDAAZ liquid flow rate (g / min) to the additive gas flow rate (ml / min) ( TDAAZ / additive gas)
Is 2 × 10 ⁻⁷ ≦ TDAAZ / added gas (g / ml)
The flow rate control mechanism is configured to maintain ≦ 2 × 10 ⁻⁴ .

As a typical example of various gases, the source gas is TDEAZ, the additive gas is ammonia gas, and each carrier gas is nitrogen gas. In the following description, this representative gas is used unless otherwise specified.

FIG. 2 is a partially enlarged sectional view of the shower head 54 provided inside the reaction vessel 10 of the CVD apparatus shown in FIG. The mixed gas 60 of the source gas and the carrier gas (N ₂ ) first enters the first diffusion chamber 62 of the shower head 54 through the first supply path 76. Next, the light enters the second diffusion chamber 68 through the dispersion holes 66 formed in the dispersion plate 64. Then, after being uniformly mixed in the diffusion chambers 62 and 68, the mixture exits the reaction vessel through the first ejection holes 56. On the other hand, ammonia gas and carrier gas (N ₂ )
The mixed gas 70 passes through the second supply path 78 and first enters the third diffusion chamber 72 of the shower head 54,
8 to the inside of the reaction vessel.

In order to carry out the method for producing a ZrN thin film of the present invention, a film was formed using the above-described CVD apparatus under the following process conditions, and the resistance value was measured.

(1) Source gas: TDAAZ (TDEA
Z): 0.01 g / min (2) Additive gas: ammonia ... 400 ml / min (3) Carrier gas: N in both TDEAZ and ammonia
₂ (4) Purge gas: Ar 50 ml (for preventing film adhesion to the back surface of the substrate, not shown) (5) Substrate temperature: 400 ° C (6) Pressure (total pressure): 40 pa ZrN formed on the substrate When the specific resistance value of the thin film was measured by a four-terminal method, it was 361 μΩ. cm. This value is, for example, a sufficiently practical resistivity value as a barrier film when used as a film thickness of 10 nm.

Next, a film was formed to a thickness of 200 nm (thickness was calculated using the bulk density), and the film quality was analyzed by RBS (Rutherford backscattering analysis). As a result, the results shown in Table 1 below were obtained. . However, the minus sign in the table indicates that the value was below the detection limit.

[0070]

[Table 1] That is, in the manufactured ZrN film, the composition of Zr and N is 1: 1 in molar ratio, and it is based on this composition ratio that the ZrN film exhibits a specific resistance close to that of a bulk. The specific resistivity of the bulk of ZrN is 18 μm.
Ω. cm.

The zirconium (Zr) and nitrogen (N) concentrations (a) in a film having a film thickness of 100 to 200 nm which is not exposed to the atmosphere, that is, has no contact with oxygen (O).
tomic%) is 50%, and silicon (S
i), oxygen (O) and carbon (C) were not measured at all. From this, it was confirmed that there was no impurity in this film, and an ideal zirconium nitride thin film having an atomic ratio of zirconium to nitrogen of 1: 1 was produced.

At this time, the film formation rate was 2.1 nm / m
The speed was sufficient for practical use.

It is desirable that the substrate temperature is not set to a high temperature, but in this embodiment, the substrate temperature is considered to be useful in practice.
° C.

Also, by adding silane (SiH ₄ ) during the formation of the zirconium nitride thin film, the crystallinity is destroyed.
It can be made amorphous to improve barrier performance.

Next, an example of a copper wiring forming apparatus which realizes the copper wiring forming method of the present invention will be described with reference to FIG.

FIG. 7 is a schematic plan view showing the overall configuration of the copper wiring forming apparatus according to the present invention. The copper wiring forming apparatus is, for example, configured as a multi-chamber type apparatus, in which a separation chamber (transfer chamber) 110 containing a substrate transfer mechanism 120 is provided at the center, and a plurality of vacuum chambers 111 are provided around the separation chamber 110. To 115 are provided. The vacuum chamber 111 is a load lock chamber as a substrate loading chamber, the vacuum chamber 112 is a reaction vessel in the apparatus for manufacturing a zirconium nitride thin film of the present invention described with reference to FIG. 1, the vacuum chamber 113 is a plasma processing chamber, and the vacuum chamber 114 is a wiring. CVD for film formation of Cu film
The chamber and the vacuum chamber 115 are load lock chambers as a substrate unloading chamber. Separation chamber 1
The vacuum chamber 11 and the vacuum chambers 111 to 115 are provided with vacuum pumping mechanisms 110a and 111a to 115a, respectively, and the insides thereof are maintained in an appropriate reduced pressure state, that is, a desired vacuum state by the vacuum pumping mechanisms. A gate valve is provided between the separation chamber and each of the vacuum chambers for taking in and out the substrate and isolating and maintaining a vacuum state inside each of the chambers, but these are not shown.

In the above-described reaction vessel 112, the above-described method for producing a zirconium nitride thin film of the present invention is carried out,
A ZrN film as a base film is formed by the method. In the CVD chamber 114, a Cu film for wiring is formed on the ZrN film by a CVD method using a raw material such as an organometallic complex.

Further, a plurality of arrows 121 shown in FIG.
4 shows a processing flow of a substrate to be processed, and shows a locus of movement of the substrate. The movement of the substrate is performed by the operation of the substrate transport mechanism 120. As is apparent from the arrow 121, the substrate carried into the copper wiring forming apparatus is kept in the reaction vessel 112 while maintaining the environment of the vacuum atmosphere.
, A plasma process in the plasma processing chamber 113, a Cu film in the CVD chamber 114, and the like are sequentially performed.

On the substrate, a ZrN film is formed under a consistent vacuum connection structure in which a vacuum atmosphere is maintained, and a Cu film is further formed thereon. That is, the ZrN
After the film is formed, the Cu film for wiring is formed in the CVD chamber 114 without exposing the surface of the film to the atmosphere.

FIG. 8 shows the effect obtained when the plasma processing is performed in the plasma processing chamber 113 on the zirconium nitride thin film manufactured by the above-described zirconium nitride thin film manufacturing method of the present invention.

An example of the process conditions for producing the zirconium nitride thin film is as follows.

(1) Source gas: TDAAZ (TDEA
Z) 0.001 g / min. (2) Additive gas: ammonia ... 3.0 ml / min. (3) Carrier gas: N for both TDEAZ and ammonia
₂ using (4) substrate temperature: 400 ° C. (5) The pressure (total pressure): 40 Pa (6) film thickness: 165 nm The sheet resistance of zirconium nitride thin film on the film forming conditions are 480Ω / squere, this thin film Are as follows.

(1) Plasma power: 2.5 KW (2) Pressure: 0.6 Pa (3) Plasma gas: H ₂ (80 ml / min.) + Trace amount of Ar (6 ml / mi)
n. ) Ar (75 ml / min.) Only (4) Processing time: 10 min. (5) Substrate temperature: 120 ° C. From the results in FIG. 8, two types of plasma gas (H ₂ + trace A) were used.
r, Ar) were prepared and the effect of the plasma treatment was confirmed by the sheet resistance, and all showed an effect of reducing the sheet resistance. In particular, when the plasma gas was used at 100% Ar gas, 480 Ω / The sheet resistance value that had been squared was reduced to 300 Ω / square.

In the above configuration, the ZrN film will be
The plasma treatment is a treatment for improving the surface of the ZrN film as described above, and is preferable, but not necessarily required. It can be omitted.

That is, when the zirconium nitride thin film in the state after film formation according to the present invention is subjected to plasma processing, as described with reference to FIG. 8, a thin film having a low resistance value of 480 Ω / square is already reduced to a lower sheet resistance. Advantageously, the value can be improved to a zirconium nitride thin film.

In particular, the formation of the ZrN film in the reaction vessel 112 and the formation of the Cu film in the CVD chamber 114 are maintained in a vacuum atmosphere via the separation chamber 110 by the substrate transfer mechanism 120, that is, It is performed in that order without exposure to the atmosphere. However, it is not always necessary to interpose the separation chamber 110 in the middle, and an arbitrary structure can be adopted as the connection structure consistent with vacuum, for example, by directly moving the reaction chamber 112 to the CVD chamber 113.

Further, the CVD chamber 114 shown in FIG. 7 is not limited to the method of forming the Cu film for wiring by the CVD method as long as a consistent connection structure is formed. it can.

The preferred embodiment of the present invention has been described with reference to the accompanying drawings. However, the present invention is not limited to the embodiment, and the present invention is not limited to the scope of the claims. It can be changed to various forms.

For example, in the above description, the explanation was mainly made with diethylamino when an ethyl group was employed as the alkyl group, but the alkyl group is not limited to this. When a methyl group is adopted, dimethylamino is
The same effect can be expected even when dipropylamino or the like in the case of employing a propyl group or a mixture of these amino groups such as methyl ethylamino group is used.

In the above description, the first vacuum gauge 14, the second vacuum gauge 16 for high vacuum, and the exhaust system 12 constitute a pressure control mechanism. However, the pressure control mechanism is limited to this embodiment. Instead, various modes can be adopted as long as the pressure in the reaction vessel 10 can be maintained at 1 Pa or more and 1500 Pa or less.

In the above description, the temperature control mechanism is constituted by the substrate heating device 30. However, if the temperature control mechanism can maintain the temperature of the substrate 20 in the range of 300.degree. Can be adopted.

Further, the flow rate control mechanism for controlling the flow rates of the raw material gas and the additional gas supplied into the reaction vessel 10 is not limited to the above-described embodiment.
The flow rate (value in the liquid state) of the source gas and the flow rate of the additional gas supplied to the reaction vessel 10 are each 0.001 g /
min to 0.1 g / min and 0.1
The ratio (TDAAZ / NH ₃ ) is maintained in the range of 1 / min or more and 5 l / min or less and the TDAAZ liquid flow rate (g / min) to the NH ₃ gas flow rate (ml / min).
Is determined as follows: 2 × 10 ⁻⁷ ≦ TDAAZ / NH ₃ (g / ml) ≦
As long as the flow rate control mechanism can be maintained at 2 × 10 ⁻⁴ , various forms can be adopted.

[0093]

According to the present invention, tetrakisdialkylaminozirconium (TDAAZ) and ammonia which is an additive gas reacting with the tetrakisdialkylaminozirconium are supplied into a reaction vessel, and the substrate heated to a predetermined temperature under a low pressure is heated. An ideal atomic ratio (ZrNx) containing no impurities is obtained by a thin film manufacturing method and a thin film manufacturing apparatus in which a zirconium nitride thin film (ZrN film) is deposited on a surface by a CVD method (chemical vapor deposition method).
(X = 1 to 1.25)), there is an effect that a low-resistance zirconium nitride thin film (ZrN film) can be formed on a low-temperature substrate at a sufficient film formation rate.

Further, according to the present invention, since the ZrN film formed as described above and the Cu film are formed in a consistent vacuum, for example, oxidation of the surface of the ZrN film used as a diffusion barrier film can be prevented. Deterioration can be prevented, and the interface between the ZrN film and the Cu film can be maintained in a good state.

That is, the Cu film and the base film are improved,
A highly reliable electronic device having high migration resistance can be manufactured.

[Brief description of the drawings]

FIG. 1 shows a zirconium nitride thin film producing apparatus (CVD apparatus) in which the method for producing a zirconium nitride thin film of the present invention is carried out.
FIG.

FIG. 2 is a partially enlarged sectional view of a shower head.

FIG. 3 shows a chemical structural formula of TDAAZ.

FIG. 4 is a diagram showing a relationship between a specific resistance value and a film forming pressure.

FIG. 5 is a diagram showing a relationship between a wafer temperature and a specific resistance value.

FIG. 6 is a diagram showing a relationship between an ammonia flow rate and a specific resistance value.

FIG. 7 is a schematic view showing an embodiment of a copper wiring forming apparatus according to the present invention.

FIG. 8 is a diagram showing the effect of plasma processing after forming a zirconium nitride thin film.

FIG. 9 is a partially enlarged cross-sectional view of the electronic device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Insulating layer 3 Depression 4 Barrier layer 5 Wiring material 10 Reaction vessel 12 Exhaust system 14 First vacuum gauge (for low vacuum) 16 Second vacuum gauge (for high vacuum) 18 Substrate holder 20 Substrate 22 Source gas introduction system 24 Additive gas introduction system 26 Turbo molecular pump 27 Pressure control valve 28 Dry pump 30 Substrate heating device 32 Thermocouple 34 Heater 35 Heating power supply 36 Material container 38 Vaporizer 40 Flow controller 42 Gas cylinder of carrier gas 44 Flow controller 46 Additive gas cylinder 48 Flow controller 50 Gas cylinder for carrier gas 52 Fourth flow controller 54 Shower head 56 First ejection hole 58 Second ejection hole 60 Mixed gas of source gas and carrier gas 62 First diffusion chamber 64 Dispersion plate 66 Dispersion hole 68 2 Diffusion chamber 70 Mixed gas of ammonia gas and carrier gas 72 Third expansion Chamber 76 first supply path 78 feeding path 110 separation chamber 111, 115 load lock reactor 113 plasma processing chamber 114 CVD chamber 110a~115a evacuation mechanism zirconium nitride thin film manufacturing apparatus of the chamber 112 present invention 120 board conveying mechanism

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Sekiguchi 5-8-1, Yotsuya, Fuchu-shi, Tokyo Anelva Co., Ltd. F-term (reference) 4K030 AA11 AA13 BA22 BA38 CA04 DA08 FA10 JA05 JA06 JA09 JA10 KA49 LA15 4M104 BB04 BB29 CC01 DD33 DD43 DD44 DD45 DD81 DD89 GG03 GG09 GG10 GG14 GG20 HH01 HH05 HH09 HH13 HH16 5F033 HH11 HH32 LL10 MM01 MM12 MM13 PP06 PP14 QQ98 VV00 VV06 WW00 XX05 XX05 XX05 XX05 XX05 XX05

Claims (10)

[Claims] 1. A zirconium nitride thin film produced by a CVD method using tetrakisdialkylaminozirconium (TDAAZ) as a raw material, wherein the composition is zirconium: nitrogen = 1: 1 to 1: 1.25 in molar ratio. Zirconium nitride thin film. 2. A nitridation method comprising the steps of plasma treating a zirconium nitride thin film having a molar ratio of zirconium: nitrogen = 1: 1 to 1: 1.25, prepared by a CVD method using tetrakisdialkylaminozirconium (TDAAZ) as a raw material. Zirconium thin film. 3. As a tetrakisdialkylaminozirconium (TDAAZ) and an additive gas reacting therewith,
Ammonia (NH ₃ ) is supplied into the reaction vessel, and 1 ≦
Total pressure (Pa) ≦ 1500 0.001 ≦ TDAAZ liquid flow rate (g / min) ≦ 0.
1 0.1 ≦ NH ₃ gas flow rate (l / min) ≦ 5 The ratio (TDAAZ / NH ₃ ) of TDAAZ liquid flow rate (g / min) to NH ₃ gas flow rate (ml / min) is 2 × 10 ⁻⁷ ≦ TDAAZ / NH ₃ (g / ml) ≦ 2 ×
A method for forming a zirconium nitride thin film, wherein a zirconium nitride thin film is formed on a surface of a substrate by a CVD method at 10 ⁻⁴ 300 ≦ substrate temperature (° C.) ≦ 450. 4. The method for producing a zirconium nitride thin film according to claim 3, wherein the tetrakisdialkylaminozirconium (TDAAZ) is tetrakisdiethylaminozirconium (TDEAZ). 5. A method for forming a copper thin film on an insulating film formed on a substrate and provided with a concave portion and filling the concave portion with a copper material, wherein the copper thin film is formed before the copper thin film is formed.
A method for forming a copper wiring, comprising the step of forming a zirconium nitride thin film using a tetrakisdialkylaminozirconium (TDAAZ) material having a composition of ZrNx (x = 1 to 1.25) by a CVD method. 6. A plasma treatment on a zirconium nitride thin film made of a tetrakisdialkylaminozirconium (TDAAZ) having a composition of ZrNx (x = 1 to 1.25) produced by a CVD method before forming a copper thin film. 6. The method according to claim 5, wherein the copper wiring is formed. 7. ZrNx (x = 1 to 1.
25) The formation of a copper thin film following the production of a zirconium nitride thin film using tetrakisdialkylaminozirconium (TDAAZ) as a raw material, or the formation of a copper thin film following a plasma treatment of the zirconium nitride thin film is sequentially and continuously performed in a vacuum. The step of forming the copper thin film is performed without exposing the zirconium nitride thin film or the zirconium nitride thin film subjected to the plasma treatment to the atmosphere and maintaining a vacuum state. 7. The method for forming a copper wiring according to 5 or 6. 8. ZrNx (x = 1 to 1.
25. The method for producing a zirconium nitride thin film according to claim 3 or 4, wherein the production of a zirconium nitride thin film using tetrakisdialkylaminozirconium (TDAAZ) having the composition of 25) as a raw material is performed. The method for forming a copper wiring according to claim 1. 9. A reaction vessel capable of being evacuated, an exhaust device for exhausting the inside of the reaction vessel, a gas supply apparatus for introducing a reaction gas into the reaction vessel, and a zirconium nitride thin film deposited thereon. A pressure control mechanism comprising: a substrate holder for holding a substrate to be heated; and a heating device for heating the substrate, wherein the pressure inside the reaction vessel can be maintained at a pressure in a range of 1 ≦ total pressure (Pa) ≦ 1500; The temperature at which is heated is 300 ≦ substrate temperature (° C.)
A temperature control mechanism capable of maintaining the temperature in a range of ≤450, and the gas supply device supplies a source gas introduction system for supplying TDAAZ gas as a source gas and an ammonia gas as an additive gas reacting therewith. The source gas introduction system and the additive gas introduction system are configured to supply the TDAAZ gas in a liquid flow rate and ammonia (NH
₃ ) The gas flow rate is 0.001 ≦ TDAAZ liquid flow rate (g / min) ≦ 0.
1 0.1 ≦ NH ₃ gas flow rate (l / min) ≦ 5 The ratio (TDAAZ / NH ₃ ) of TDAAZ liquid flow rate (g / min) to NH ₃ gas flow rate (ml / min) is 2 × 10 ⁻⁷ ≦ TDAAZ / NH ₃ (g / ml) ≦ 2 ×
An apparatus for producing a zirconium nitride thin film, comprising: a flow rate control mechanism for controlling the relation of 10 ⁻⁴ to be satisfied. 10. The apparatus for producing a zirconium nitride thin film according to claim 9, wherein a zirconium nitride thin film is formed.
The film forming apparatus for forming the u film is connected by a consistent connection structure in a vacuum, and the substrate on which the zirconium nitride thin film is formed by the zirconium nitride thin film forming apparatus is not exposed to the atmosphere, and the vacuum state is maintained. A copper wiring film is formed by a film forming apparatus for forming a wiring Cu film.