JP2001049434A - METHOD FOR FORMATION OF TiN FILM AND PRODUCTION OF ELECTRONIC PARTS - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a TiN film capable of obtaining a barrier film or the like high in reliability by feeding tetrakis-(dialkylamino)- titanium(TDAAT) high in purity and small in impurities and to provide a method for producing electronic parts using this. SOLUTION: The method for forming a TiN film has a stage in which TDAAT is filled from a TDAAT feeding device 17 into a vaporizing chamber 4, a stage in which carrier gas is introduced into the vaporizing chamber, and a gaseous mixture of carrier gas and TDAAT is introduced from the vaporizing chamber into a reactor 5 (a stage of introducing the gaseous nitrogen compd. into the reactor), a stage in which a TiN film forming substrate 8 in the reactor is heated to a desired temp. to form a TiN film on the TiN film forming substrate and a stage in which exhaust gas is exhausted from the reactor. In this case, the TDAAT feeding device is provided with at least one optical liq. face sensor as a liq. quantity monitoring means for TDAAT.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chemical vapor deposition (C) process.
The present invention relates to a method of forming a TiN film by a VD) method and a method of manufacturing an electronic component using the same.

[0002]

2. Description of the Related Art In a semiconductor device or the like in an electronic component, a metal such as aluminum as a wiring material reacts with silicon of a substrate at the bottom of a connection hole due to a heat treatment in a wiring process, and a problem arises that a junction is broken. In order to avoid this problem, a TiN (titanium nitride) film is formed as a barrier layer between a metal such as aluminum and silicon of the substrate.

Conventionally, such a barrier layer of TiN has been formed by a sputtering method. However, as the aspect ratio increases with the increase in the degree of integration of semiconductor devices, a problem arises in step coverage in the sputtering method. It became.

Therefore, in recent years, CVs having excellent step coverage have been developed.
A TiN film is formed by the method D, and tetrakis (dialkylamino) titanium (TDAAT) is used as a raw material.
Alternatively, a CVD method is performed using a nitrogen compound gas such as ammonia as an additional gas.

[0005]

However, in semiconductor devices, multi-layer wiring has been progressing along with further miniaturization, and a more reliable film has been required for a barrier layer. There is a demand for supply of TDAAT with higher purity and less impurities.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of forming a TiN film capable of obtaining a highly reliable barrier film or the like by supplying TDAAT of high purity and containing few impurities in order to solve the above problems. An object of the present invention is to provide a method for manufacturing an electronic component using the same.

[0007]

That is, the present invention provides a TDAA.
A step of charging TDAAT into the vaporization chamber from the T supply device; a step of introducing a carrier gas into the vaporization chamber and a step of introducing a carrier gas / TDAAT mixed gas from the vaporization chamber to the reactor; a substrate on which a TiN film is to be formed in the reactor is desired Forming a TiN film on a substrate on which the TiN film is formed by heating to a temperature; and exhausting exhaust gas from the reactor. A method for forming a TiN film characterized by comprising two optical liquid level sensors;
And a step of introducing a nitrogen compound gas into the reactor.
The present invention relates to a method for forming an iN film.

Further, the present invention relates to a method for manufacturing an electronic component, wherein the method for forming a TiN film is employed for forming a TiN film in manufacturing an electronic component having a TiN film as a constituent element.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of forming a TiN film according to the present invention
A conventional CVD apparatus is used, but a TDAAT supply apparatus for supplying TDAAT to the CVD apparatus is provided with at least one optical liquid level sensor as TDAAT liquid level monitoring means. There is a feature. More specifically, the TDAAT supply device comprises:
It is composed of a stainless steel container main body whose inner surface is electrolytically polished, and a lid that can be joined to the container main body. The container main body and / or the lid are connected to the container main body by T.
It has a TDAAT inlet for injecting DAAT, a TDAAT supply port for taking out TDAAT from the container main body, and at least one optical level sensor.

First, the TDAAT supply device will be described in detail. The feature of the TDAAT supply device used in the present invention is that the inside of the container body portion of the TDAAT supply device composed of a stainless steel container main body whose inner surface is electrolytically polished and a lid that can be joined to the container main body. An optical liquid level sensor is used to detect the remaining amount of TDAAT.

An optical liquid level sensor usable in the TDAAT supply device has a light emitting optical fiber and a light receiving optical fiber, and the light emitted from the light emitting optical fiber is forwardly transmitted to the light receiving optical fiber in front of the ends of both optical fibers. In this case, a light detection probe provided with a prism portion having a plurality of internal reflection surfaces for incidence is used.

FIG. 3 shows a light detection probe of this optical liquid level sensor. In FIG. 3, a right-angle prism (22) having an internal reflection surface is provided at the distal end of the light-projecting optical fiber (20) and the light-receiving optical fiber (21) installed in parallel. The protective tube (23) for protecting the light emitting optical fiber (20) and the light receiving optical fiber (21) is integrally formed with the right-angle prism (22) and can be made of fluororesin or the like.

An optical liquid level sensor provided with such a light detection probe operates as follows. First, when the right-angle prism (22) of the light detection probe is not immersed in TDAAT or is immersed only to a certain level, the light emitted from the light emitting optical fiber (20) is converted into the right-angle prism (22). The light is reflected by the internal reflection surface of the light incident on the light receiving optical fiber (21), and is reflected by the right-angle prism (2).
The configuration is such that light is not scattered to the outside via 2), and the difference between the intensity of the emitted light and the intensity of the incident light is small when the intensity of the emitted light and the intensity of the incident light are measured.

On the other hand, when the right-angle prism (22) is immersed in the TDAAT at a certain level or higher, most of the light emitted from the light-projecting optical fiber (20) is substantially perpendicular to the right-angle prism (22). Therefore, almost no incident light is transmitted through the internal reflection surface of the right-angle prism (22) and reflected by the internal reflection surface of the right-angle prism (22) to enter the light receiving optical fiber (21). In this case, the outgoing light travels through the TDAAT via the right-angle prism (22) and is scattered. Therefore, the incident light entering through the right-angle prism (22) is very weak,
When the intensity of the outgoing light and the intensity of the incident light are detected, the difference between the intensity of the outgoing light and the intensity of the incident light increases, and it is possible to detect that the liquid level of the TDAAT is above a certain level of the right-angle prism (22). It has a configuration that can be used.

By the way, when an optical liquid level sensor having a light detecting probe having the structure shown in FIG. 3 is installed near the bottom of the container body, the right angle prism (2
In some cases, the outgoing light that passes through 2) and travels through the TDAAT is reflected by the bottom of the container body and becomes incident light via the right-angle prism (22). In such a case, the difference between the intensity of the outgoing light and the intensity of the incident light becomes small, and it may be difficult to detect the liquid level of TDAAT. In such a case,
By using the light detection probe having the configuration shown in FIG. 4, the difference between the emitted light and the incident light can be increased. That is, as shown in FIG. 4, the light-emitting optical fiber (20) and the light-receiving optical fiber (21) are configured such that the distal ends of the light-emitting optical fiber (20) and the light-receiving optical fiber (21) are expanded toward each other. ), The light emitting axis and the light incident axis of the light receiving optical fiber (21) are provided with a certain angle. When the light detection probe having such a configuration is installed near the bottom of the container body, even if the outgoing light transmitted through the conical prism (24) is reflected on the bottom surface, the incident light from the conical prism (24) is used. As a result, the intensity of the incident light can be further reduced, and thus the difference between the intensity of the emitted light and the intensity of the incident light when the intensity of the emitted light and the intensity of the incident light are detected. Can be made larger. That is, it can be more clearly determined that the liquid level of TDAAT is at or above a certain level of the conical prism (24).

An optical liquid level sensor provided with a light detection probe as shown in FIGS. 3 and 4 is an optical fiber for light projection in a protective tube (for example, made of fluororesin) integrally formed with a prism portion at the tip. (20) and the optical fiber for light reception (21) are accommodated, and the optical liquid level sensor having such a configuration has no mechanical contact between the constituent members, and thus generates new particles. Never. Therefore, the TDAAT can be supplied without being contaminated by installing the optical liquid level sensor having the above-described configuration at at least one portion of the container body of the TDAAT supply device and monitoring the remaining amount of the TDAAT. be able to.

Further, in order to accurately install the light detecting probe portion of the optical liquid level sensor at a predetermined position near the bottom of the container body, a light transmitting optical fiber (20) and a light receiving light are placed in a protective tube (23). It is also possible to adopt a configuration in which a support rod (for example, a metal rod) is inserted together with the optical fiber (21) for use so that the shape of the optical liquid level sensor can be maintained.

Further, two or more optical liquid level sensors are installed such that their light detecting probes have a step, and
Before the remaining amount of DAAT reaches the TDAAT liquid level detection position of the lower light detection probe, a warning may be issued at the TDAAT liquid level detection position of the other light detection probe provided above the lower light detection probe. .

By using the TDAAT supply device having the above-described structure, the method for forming a TiN film of the present invention provides a high purity TDAAT with very few impurities.
Raw materials can be used. Further, since the remaining amount of TDAAT of the TDAAT supply device can be managed with high precision, the TDAAT of the TDAAT supply device can be used efficiently, and when the remaining amount of TDAAT of the TDAAT supply device becomes small, the next TDAAT supply device becomes available. Replacement work etc. can be performed extremely smoothly.

In the method of forming a TiN film according to the present invention, T
DAAT is charged into the TDAAT vaporization chamber from the TDAAT supply device. TD filled in TDAAT vaporization chamber
AAT is kept at a constant temperature to secure a constant vapor pressure. TDAAT is preferably from 40 ° C to 70 ° C, more preferably from 50 ° C to 60 ° C.

The TDAAT used in the present invention preferably has an alkyl group having 1 to 3 carbon atoms, which may be the same or different, more preferably a methyl group or an ethyl group. Specifically, for example, tetrakis (dimethylamino) titanium (TDMA)
T), tetrakis (diethylamino) titanium (TDEA)
T), tetrakis (ethylmethylamino) titanium (TE
MAT) can be preferably used.

Here, a carrier gas (for example, an inert gas such as N ₂ or Ar) is introduced into the TDAAT vaporization chamber to generate a carrier gas / TDAAT mixed gas.
Further, this is introduced into the reactor. TDAAT
Carrier gas and TDAAT by adjusting the temperature of
The TDAAT concentration in the mixed gas can be controlled.

In the method for forming a TiN film according to the present invention,
A nitrogen compound gas can be introduced into the reactor in parallel with the introduction of the TDAAT-containing gas into the reactor. Ammonia (NH ₃ ) or the like can be used as the nitrogen compound gas.

With the above gas introduced into the reaction chamber, T
By heating the substrate on which the iN film is formed to a desired temperature, a TiN film is formed (deposited) on the substrate. The substrate temperature at this time is preferably 350 ° C. to 700 ° C., and more preferably 400 ° C. to 600 ° C. The film thickness can be arbitrarily controlled by increasing or decreasing the film growth time (TiN deposition time).

[0025]

EXAMPLES Next, examples are shown to specifically explain the method for forming a TiN film of the present invention.

Embodiment 1 FIG. 1 is a schematic structural view of a CVD apparatus used in the method of forming a TiN film according to the present invention. In FIG. 1, a reactor (chamber) (5) for forming a TiN film includes a dispersion head (6), a heater (7), and a Si wafer substrate (8) as a substrate on which a TiN film is formed. I have.

An exhaust port (9) for exhausting the atmosphere in the reactor (5) is provided. Further, the carrier gas is supplied to the T via a flow meter (1b) and a valve (2b).
It is configured so that it can be supplied to the DAAT vaporization chamber (4).
The TDAAT vaporization chamber (4) is supplied with TDAAT from a TDAAT supply device (17).

Next, the TDAAT supply device (17) shown in FIG. 1 will be described in detail with reference to FIG. TDA shown in FIG.
The AT supply device (17) is composed of a TDAAT supply device container body (10) made of stainless steel whose inner surface is electrolytically polished, and a lid (19) that can be joined to the TDAAT supply device container body (10). Have been. Where TD
The container body (10) of the AAT supply device and the lid (19) are air-tightly joined to each other by a joining means such as a bolt and a nut (18), for example.

The lid (19) has a TDAAT for injecting TDAAT into the TDAAT supply device container body (10).
A DAAT inlet (12), a TDAAT supply port (11) for removing TDAAT from the TDAAT supply device container main body (10), and an optical liquid level sensor (13) are provided. The TDAAT inlet (12) has a TD
The valve (2e) for controlling the injection of AAT has a TD
A valve (2d) for controlling the supply of TDAAT is provided at the AAT supply port (11). The light detection probe (14) at the tip of the optical liquid level sensor (13) is provided at a predetermined position around the bottom of the TDAAT supply device container body (10). The optical liquid level sensor (13) is connected to a light emitting / receiving device (15) and a detection circuit (16), and detects and detects the remaining amount of TDAAT based on a signal output from the detection circuit (16). When the amount falls below a predetermined amount, the supply of TDAAT is stopped,
It is configured so that various controls such as stopping the operation of the D device can be performed.

First, as a raw material TDAAT, high purity TD is used.
The MAT is operated via the TDAAT inlet (12) by operating the valve (2e), and the TDAAT feeder container body (10)
Was filled. Next, the TDAAT supply device container body (1
0) to the TDAAT vaporization chamber (4) by operating the valve (2d) through the TDAAT supply port (11) to TDMAT.
Was charged. At this time, the end point of the TDMAT supply amount was monitored using an optical liquid level sensor (13) having a light detection probe (14) installed in the TDAAT supply device container body (10).

TDM filled in TDAAT vaporization chamber (4)
The AT was kept at 55 ° C. to keep the vapor pressure constant, and the Si wafer substrate (8) in the reactor (5) was heated by the heater (7) for 5 hours.
Heated to 00 ° C.

Next, Ar was used as a carrier gas in TDAAT.
Gas was blown into the vaporization chamber (4) at a rate of 50 ml / min, and a gas containing TDMAT was introduced into the reactor (5). Exhaust gas from the reactor (5) is removed from the exhaust port (9) at a reduced pressure of 1 Torr, and a reaction for 10 minutes is performed on the Si wafer (8).
A TiN film having a thickness of about 30 nm was formed.

When the same operation is performed, the amount of impurities in the high-purity TDMAT filled in the TDAAT vaporization chamber (4) from the TDAAT supply device (17) is measured by measuring the number of particles of 0.2 μm or more. did. The result is 1
4.9 (pieces / milliliter). Further, the obtained TiN film was uniform with few impurities and was excellent as a barrier layer of a semiconductor device with fine wiring, and the LSI manufactured by this was excellent.

[Embodiment 2] FIG. 5 shows the C used in this embodiment.
FIG. 2 is a schematic structural diagram of a VD device. That is, the CV shown in FIG.
The apparatus D is provided with means for introducing NH ₃ gas as a nitrogen compound gas into the reactor (5). NH
_{The three} gases are introduced into the reactor (5) via the flow meter (1a) and the valve (2a).

First, as a raw material TDAAT, high purity TD is used.
The MAT is operated via the TDAAT inlet (12) by operating the valve (2e), and the TDAAT feeder container body (10)
Was filled. Next, the TDAAT supply device container body (1
0) to the TDAAT vaporization chamber (4) by operating the valve (2d) through the TDAAT supply port (11) to TDMAT.
Was charged. At this time, the end point of the TDAAT supply amount was monitored using an optical liquid level sensor (13) having a light detection probe (14) installed in the TDAAT supply device container body (10).

TDM filled in TDAAT vaporization chamber (4)
The AT was kept at 55 ° C. to keep the vapor pressure constant, and the Si wafer substrate (8) in the reactor (5) was heated by the heater (7) for 5 hours.
Heated to 00 ° C.

Next, Ar was used as a carrier gas in TDAAT.
Gas was blown into the vaporization chamber (4) at a rate of 50 ml / min, and a gas containing TDMAT was introduced into the reactor (5). Furthermore,
Ammonia is introduced into the reactor (5) as nitrogen compound gas.
Exhaust gas from the reactor (5) was removed from the exhaust port (9) at a reduced pressure of 1 Torr at a rate of 1 ml / min, and a 10-minute reaction was performed to form a TiN film having a thickness of about 30 nm on the Si wafer (8). Was formed.

The amount of impurities in the high-purity TDMAT filled in the TDAAT vaporization chamber (4) from the TDAAT supply device (17) when the same operation was performed was measured by measuring the number of particles of 0.2 μm or more. did. The result is 1
4.7 (pieces / milliliter). Further, the obtained TiN film was uniform with few impurities and was excellent as a barrier layer of a semiconductor device with fine wiring, and the LSI manufactured by this was excellent.

Example 3 High purity TD as TDAAT
The procedure was performed in the same manner as in Example 1 except that EAT was used. The amount of impurities was 14.2 (pieces / milliliter). Further, the obtained TiN film was uniform with few impurities and was excellent as a barrier layer of a semiconductor device with fine wiring, and the LSI manufactured by this was excellent.

Example 4 High purity TD as TDAAT
The procedure was performed in the same manner as in Example 2 except that EAT was used. The amount of impurities was 14.8 (pieces / milliliter). Further, the obtained TiN film was uniform with few impurities and was excellent as a barrier layer of a semiconductor device with fine wiring, and the LSI manufactured by this was excellent.

Example 5 High purity TE as TDAAT
The procedure was performed in the same manner as in Example 1 except that MAT was used. The amount of impurities was 14.5 (pieces / milliliter). Further, the obtained TiN film was uniform with few impurities and was excellent as a barrier layer of a semiconductor device with fine wiring, and the LSI manufactured by this was excellent.

Example 6 High purity TE as TDAAT
The procedure was performed in the same manner as in Example 2 except that MAT was used. The amount of impurities was 15.0 (pieces / milliliter). Further, the obtained TiN film was uniform with few impurities and was excellent as a barrier layer of a semiconductor device with fine wiring, and the LSI manufactured by this was excellent.

Comparative Example 1 In the same manner as in Example 1, except that a TDAAT supply device having a conventionally used float type liquid level sensor is used instead of the optical liquid level sensor as the TDAAT supply device. About 30 nm TiN
A film was formed.

The high-purity TDM filled in the TDAAT vaporization chamber from the TDAAT supply device when the same operation was performed.
The amount of impurities in the AT was measured by measuring the number of particles of 0.2 μm or more. The result was 982 (pieces / milliliter). Further, the obtained TiN film was not suitable for a barrier layer of a semiconductor device having fine wiring due to impurities, and the LSI manufactured by this was defective.

[0045]

The effects of the present invention are as follows: a method of forming a TiN film capable of obtaining a highly reliable barrier film or the like by supplying TDAAT with high purity and few impurities, and a method of manufacturing an electronic component using the same. Is to provide.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a CVD apparatus used in Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of a TDAAT supply device used in an example.

FIG. 3 shows a TDA used in the method for forming a TiN film of the present invention.
FIG. 3 is a diagram illustrating a configuration of a light detection probe of an optical liquid level sensor of the AT supply device.

FIG. 4 is a diagram showing another configuration of the light detection probe of the optical liquid level sensor.

FIG. 5 is a schematic structural view of a CVD apparatus used in Embodiment 2 of the present invention.

[Explanation of symbols]

 1a-1b: Flow meter 2a-2e: Valve 4: TDAAT vaporization chamber 5: Reactor (chamber) 6: Dispersion head 7: Heater 8: Substrate on which TiN film is formed (silicon wafer) 9: Exhaust port 10: TDAAT supply Device container body 11: TDAAT supply port 12: TDAAT injection port 13: Optical liquid level sensor 14: Optical detection probe 15: Emitter / receiver 16: Detection circuit 17: TDAAT supply device 18: Bolt and nut 19: Lid 20: Projecting optical fiber 21: Receiving optical fiber 22: Right angle prism 23: Protective tube 24: Conical prism

Claims (8)

[Claims] 1. A step of filling tetrakis (dialkylamino) titanium into a vaporization chamber from a tetrakis (dialkylamino) titanium supply device; introducing a carrier gas into the vaporization chamber; and mixing a carrier gas and tetrakis (dialkylamino) titanium from the vaporization chamber. A step of introducing a gas into the reactor; a step of heating the substrate on which the TiN film is formed in the reactor to a desired temperature to form a TiN film on the substrate on which the TiN film is formed; and a step of discharging exhaust gas from the reactor. In the method for forming a film, the tetrakis (dialkylamino) titanium supply device includes at least one optical liquid level sensor as a means for monitoring the liquid amount of tetrakis (dialkylamino) titanium. . 2. A step of filling tetrakis (dialkylamino) titanium into a vaporization chamber from a tetrakis (dialkylamino) titanium supply device; introducing a carrier gas into the vaporization chamber; and mixing a carrier gas and tetrakis (dialkylamino) titanium from the vaporization chamber. Introducing gas into the reactor; introducing nitrogen compound gas into the reactor; TiN in the reactor
A method for forming a TiN film on a TiN film-forming substrate by heating the film-forming substrate to a desired temperature; and a method for forming a TiN film comprising exhausting exhaust gas from a reactor. Wherein at least one optical liquid level sensor is provided as a means for monitoring the amount of tetrakis (dialkylamino) titanium. 3. The tetrakis (dialkylamino) titanium is one or more selected from the group consisting of tetrakis (dimethylamino) titanium, tetrakis (diethylamino) titanium, and tetrakis (ethylmethylamino) titanium. Item 3. The Ti according to item 1 or 2.
Method for forming N film. 4. A tetrakis (dialkylamino) titanium supply device is composed of a stainless steel container main body whose inner surface is electrolytically polished, and a lid which can be joined to the container main body. And / or a lid having a tetrakis (dialkylamino) titanium inlet for injecting tetrakis (dialkylamino) titanium into the container main body, and a tetrakis (dialkyl) for taking out tetrakis (dialkylamino) titanium from the container main body. The method for forming a TiN film according to any one of claims 1 to 3, further comprising an amino) titanium supply port and at least one optical liquid level sensor. 5. An optical liquid level sensor comprising: a light projecting optical fiber and a light receiving optical fiber juxtaposed, and a plurality of optical liquid level sensors for causing light emitted from the light projecting optical fiber to enter the light receiving optical fiber in front of the ends of both optical fibers. 5. The method for forming a TiN film according to claim 4, wherein a light detection probe provided with a prism having an internal reflection surface is used. 6. The method for forming a TiN film according to claim 5, wherein the tip ends of the light projecting optical fiber and the light receiving optical fiber in the light detection probe are widened forward. 7. The internal electrolytic polishing stainless steel container is provided with a lid having a wide mouth to such an extent that the internal cleaning is possible.
The method for forming a TiN film according to any one of the above items. 8. A method of forming a TiN film according to any one of claims 1 to 7, in forming a TiN film in manufacturing an electronic component including the TiN film as a constituent element. Manufacturing method of electronic components.