JP2001041802A - FORMATION METHOD OF TiN FILM AND MANUFACTURE OF ELECTRONIC PART - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable barrier film by introducing a mixed gas of carrier gas and high-purity titanium tetra-chloride into a reactor from a vaporizer, and heating a TiN film formation substrate in the reactor to a desired temperature for generating plasma in it. SOLUTION: A titanium tetra-chloride supply device 17 comprises a vessel body 10 of stainless steel whose inside surface is electrolytically polished and a lid part 19 which is provided a titanium tetra-chloride injection opening 12, a supply opening, and an optical liquid-level sensor 13. Firstly, the high-purity titanium tetra-chloride which is a material is fed in the vessel body 10 through the injection opening 12, and the titanium tetra-chloride is fed in a carburetor 4 from the vessel body 10 through the supply opening 11. Then, Ar which is carrier gas is blown into the vaporizer 4 so that a mixed gas is introduced into a reactor 5 while ammonium is blown-in as a nitrogen mixed gas. A high- frequency voltage is applied from a matching unit 3 to generate plasma in the reactor 5 to form a TiN film.

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 a method D, and a CVD method is performed using titanium tetrachloride (TiCl ₄ ) as a titanium source and ammonia as a nitrogen source.

[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 a supply of titanium tetrachloride 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 titanium tetrachloride of high purity and containing few impurities in order to solve the above problems. And a method of manufacturing an electronic component using the same.

[0007]

That is, the present invention relates to a process of filling titanium tetrachloride into a vaporization chamber from a titanium tetrachloride supply device; introducing a carrier gas into the vaporization chamber, and mixing the carrier gas and titanium tetrachloride from the vaporization chamber. Introducing a gas into the reactor; introducing a nitrogen compound gas into the reactor; heating the substrate on which the TiN film is formed in the reactor to a desired temperature, and generating plasma in the reaction chamber to form the TiN film. T on the substrate
forming an iN film; a method for forming a TiN film having a step of discharging exhaust gas from a reactor, wherein the titanium tetrachloride supply device includes at least one optical liquid level sensor as a titanium tetrachloride liquid amount monitoring means. The present invention relates to a method for forming a TiN film, comprising:

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
Although a conventional CVD apparatus is used, a titanium tetrachloride supply apparatus for supplying titanium tetrachloride to the CVD apparatus includes at least one optical liquid level sensor as titanium tetrachloride liquid amount monitoring means. There is a feature in the use of such a thing. More specifically, the titanium tetrachloride supply device includes a container body made of stainless steel whose inner surface is electrolytically polished, and a lid that can be joined to the container body, and the container body and / or Or, the lid is a titanium tetrachloride inlet for injecting titanium tetrachloride into the container main body, a titanium tetrachloride supply port for removing titanium tetrachloride from the container main body, and at least one optical liquid level This is a configuration having a sensor.

First, the titanium tetrachloride supply device will be described in detail. The titanium tetrachloride supply device used in the present invention is characterized by a titanium tetrachloride 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 titanium tetrachloride in the container body.

An optical liquid level sensor usable in the titanium tetrachloride supply device has a light emitting optical fiber and a light receiving optical fiber arranged side by side, and receives light emitted from the light emitting optical fiber in front of the tips of both optical fibers. In this case, a light detection probe provided with a prism portion having a plurality of internal reflection surfaces for entering the optical fiber 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 titanium tetrachloride or is only immersed to a certain level, the light emitted from the light-emitting optical fiber (20) is converted into the right-angle prism (22). 22), is reflected by the internal reflection surface, is incident on the optical fiber for light reception (21), and is incident on 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 titanium tetrachloride at a certain level or higher, most of the light emitted from the light-projecting optical fiber (20) is almost right-angle prism (22). The incident light transmitted through the internal reflection surface of the optical fiber 22) and reflected by the internal reflection surface of the right-angle prism 22 and incident on the light receiving optical fiber 21 is almost eliminated. In this case, the emitted light travels through titanium tetrachloride via the right-angle prism (22) and is scattered. Therefore, the incident light that enters through the right-angle prism (22) is very weak, and when the intensity of the outgoing light and the incident light is detected, the difference between the intensity of the outgoing light and the intensity of the incident light increases. The configuration is such that it is possible to detect that the surface is above a certain level of the right-angle prism (22).

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
Outgoing light that passes through 2) and travels through titanium tetrachloride may be reflected by the bottom of the container body and become incident light via the right-angle prism (22). In such a case, the difference between the intensity of the emitted light and the intensity of the incident light becomes small, and it may be difficult to detect the liquid level of titanium tetrachloride. In such a case, the difference between the emitted light and the incident light can be increased by using a light detection probe having a configuration as shown in FIG. 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 titanium tetrachloride 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 titanium tetrachloride is contaminated by installing the optical liquid level sensor having the above-described configuration at at least one position in the container main body of the titanium tetrachloride supply device and monitoring the remaining amount of titanium tetrachloride. Can be supplied without doing.

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.

Also, two or more optical liquid level sensors are installed so that their light detecting probes have a step, and the titanium tetrachloride residual amount is determined by the titanium tetrachloride liquid level detecting position of the lower light detecting probe. Prior to this, a warning may be issued at the titanium tetrachloride liquid level detection position of the other light detection probe provided thereabove.

By using the titanium tetrachloride supply apparatus having the above-described configuration, in the method of forming a TiN film of the present invention, it is possible to use a high-purity titanium tetrachloride raw material having extremely few impurities. In addition, since the titanium tetrachloride remaining amount of the titanium tetrachloride supply device can be accurately controlled, the titanium tetrachloride of the titanium tetrachloride supply device can be efficiently used, and the titanium tetrachloride residue of the titanium tetrachloride supply device can be efficiently used. When the amount becomes small, the replacement work with the next titanium tetrachloride supply device can be performed extremely smoothly.

In the method of forming a TiN film according to the present invention, titanium tetrachloride is charged into the titanium tetrachloride vaporization chamber from the above-mentioned titanium tetrachloride supply device. The titanium tetrachloride filled in the titanium tetrachloride vaporization chamber is kept at a constant temperature to secure a constant vapor pressure. Here, the temperature of the titanium tetrachloride is preferably 40 ° C to 70 ° C, more preferably 50 ° C to 60 ° C. Here, a carrier gas (for example, an inert gas such as N ₂ or Ar) is introduced into a titanium tetrachloride vaporization chamber to generate a carrier gas / titanium tetrachloride mixed gas, which is then introduced into a reactor. It is. By adjusting the temperature of titanium tetrachloride, the concentration of titanium tetrachloride in the carrier gas / titanium tetrachloride mixed gas can be controlled.

In the method of forming a TiN film according to the present invention,
A nitrogen compound gas is introduced into the reactor in parallel with the introduction of the titanium tetrachloride-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).

[0023]

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 of the present invention. In FIG.
Reactor (chamber) for forming TiN film (5)
Is the dispersion head (6), heater (7), T
It is composed of a Si wafer substrate (8) as a substrate on which an iN film is formed.

The nitrogen compound gas used for the reaction in the reactor (5) can be supplied through a flow meter (1a) and a valve (2a). In the reactor (5)
An exhaust port (9) for exhausting the inside atmosphere is provided. The carrier gas can be supplied to the titanium tetrachloride vaporization chamber (4) via the flow meter (1b) and the valve (2b). Further, a voltage is applied to the dispersion head (6) by the matching unit (3) so that plasma can be generated in the reactor (5). The titanium tetrachloride vaporization chamber (4) is supplied with titanium tetrachloride from a titanium tetrachloride supply device (17).

Next, the titanium tetrachloride supply device (17) shown in FIG. 1 will be described in detail with reference to FIG. The titanium tetrachloride supply device (17) shown in FIG. 2 is a stainless steel titanium tetrachloride supply device container body (1
0) and a lid (19) that can be joined to the titanium tetrachloride supply device container body (10). Here, the titanium tetrachloride supply device container body (10) and the lid (1)
In 9), for example, the flange portions are joined in an airtight state by joining means such as bolts and nuts (18).

The lid (19) has a titanium tetrachloride inlet (12) for injecting titanium tetrachloride into the titanium tetrachloride supply container main body (10), and a titanium tetrachloride supply container main body (10). ) And an optical liquid level sensor (1).
3) is provided. The titanium tetrachloride inlet (1
A valve (2e) for controlling the injection of titanium tetrachloride is provided in 2), and a valve (2d) for controlling the supply of titanium tetrachloride is provided in the titanium tetrachloride supply port (11). ing. The light detection probe (14) at the tip of the optical liquid level sensor (13) is installed at a predetermined position around the bottom of the titanium tetrachloride supply device container body (10). Further, the optical liquid level sensor (13) is connected to a light emitting and receiving device (15) and a detection circuit (16),
Various controls such as detecting the remaining amount of titanium tetrachloride based on the signal output from the detection circuit (16) and stopping the supply of titanium tetrachloride and stopping the operation of the CVD apparatus when the remaining amount becomes equal to or less than a predetermined amount. Can be performed.

First, the raw material of high purity titanium tetrachloride was charged into the titanium tetrachloride supply device container body (10) through the titanium tetrachloride injection port (12) by operating the valve (2e). Next, titanium tetrachloride was charged from the titanium tetrachloride supply device container body (10) to the titanium tetrachloride vaporization chamber (4) through the titanium tetrachloride supply port (11) by operating the valve (2d). At this time, the end point of the supply amount of titanium tetrachloride was monitored using an optical liquid level sensor (13) having a light detection probe (14) installed in the titanium tetrachloride supply device container body (10).

The titanium tetrachloride filled in the titanium tetrachloride vaporization chamber (4) is kept at 55 ° C. to keep the vapor pressure constant.
The Si wafer substrate (8) in the reactor (5) is heated (7)
To 500 ° C.

Next, Ar as a carrier gas was blown into the titanium tetrachloride vaporization chamber (4) at 50 ml / min, and a gas containing titanium tetrachloride was introduced into the reactor (5). Further, ammonia is blown into the reactor (5) at a rate of 5 ml / min as a nitrogen compound gas, and the exhaust gas from the reactor (5) is removed from the exhaust port (9) at a reduced pressure of 1 Torr, and the matching unit (3) A high frequency voltage of 13.56 MHz is applied to generate plasma in the reactor (5),
After the reaction for 0 minutes, a thickness of about 30 n was formed on the Si wafer (8).
m of TiN film was formed.

When the same operation was performed, the amount of impurities in the high-purity titanium tetrachloride filled in the titanium tetrachloride vaporization chamber (4) from the titanium tetrachloride supply device (17) was reduced to the number of particles of 0.2 μm or more. Was measured. The result 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 A titanium tetrachloride supply apparatus having a float type liquid level sensor conventionally used instead of an optical liquid level sensor was used as the titanium tetrachloride supply apparatus in the same manner as in Example 1. Using T about 30nm thick
An iN film was formed.

The amount of impurities in the high-purity titanium tetrachloride filled in the titanium tetrachloride vaporization chamber from the titanium tetrachloride supply device when the same operation was performed was measured by measuring the number of particles of 0.2 μm or more. did. The result is 976
(Pieces / milliliter). In addition, the obtained TiN
The film was not suitable as a barrier layer of a semiconductor device having fine wiring due to impurities, and the LSI manufactured by this was defective.

[0033]

As described above, the present invention provides a method of forming a TiN film capable of obtaining a highly reliable barrier film or the like by supplying titanium tetrachloride having high purity and few impurities, and an electronic component using the same. It is to provide a manufacturing method.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram of a titanium tetrachloride supply device used in Examples.

FIG. 3 is a diagram showing a configuration of a light detection probe of an optical liquid level sensor of a titanium tetrachloride supply device used in the method of forming a TiN film of the present invention.

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

[Explanation of symbols]

 1a-1b: Flow meter 2a-2e: Valve 3: Matching unit 4: Titanium tetrachloride vaporization chamber 5: Reactor (chamber) 6: Dispersion head 7: Heater 8: Substrate on which TiN film is formed (silicon wafer) 9: Exhaust port 10: Titanium tetrachloride supply device container body 11: Titanium tetrachloride supply port 12: Titanium tetrachloride inlet 13: Optical liquid level sensor 14: Optical detection probe 15: Emitter / receiver 16: Detection circuit 17: Tetrachloride Titanium supply device 18: Bolt and nut 19: Lid 20: Light emitting optical fiber 21: Light receiving optical fiber 22: Right angle prism 23: Protective tube 24: Conical prism

Claims (6)

[Claims] 1. A step of charging titanium tetrachloride into a vaporization chamber from a titanium tetrachloride supply device; a step of introducing a carrier gas into a vaporization chamber and a step of introducing a carrier gas / titanium tetrachloride mixed gas from a vaporization chamber into a reactor; A step of introducing a nitrogen compound gas into the reactor; heating the substrate on which the TiN film is formed in the reactor to a desired temperature, and generating plasma in the reaction chamber to produce TiN.
Forming a TiN film on the film-forming substrate; discharging the exhaust gas from the reactor, wherein the titanium tetrachloride supply device includes at least one titanium tetrachloride liquid amount monitoring means. A method for forming a TiN film, comprising an optical liquid level sensor. 2. The titanium tetrachloride supply device includes a container body made of stainless steel whose inner surface is electrolytically polished, and a lid that can be joined to the container body, and the container body and / or A lid, a titanium tetrachloride inlet for injecting titanium tetrachloride into the container body, a titanium tetrachloride supply port for removing titanium tetrachloride from the container body, and at least one optical level sensor 2. The method for forming a TiN film according to claim 1, wherein the method comprises: 3. An optical liquid level sensor comprising a light projecting optical fiber and a light receiving optical fiber juxtaposed, wherein light emitted from the light projecting optical fiber is made to enter the light receiving optical fiber in front of the distal ends of the two optical fibers. 3. The method for forming a TiN film according to claim 2, wherein a light detection probe provided with a prism portion having an internal reflection surface is used. 4. The method for forming a TiN film according to claim 3, wherein the tip ends of the light projecting optical fiber and the light receiving optical fiber in the light detection probe are widened forward. 5. The internal electrolytic polishing stainless steel container is provided with a lid having a wide opening to enable internal cleaning.
The method for forming a TiN film according to any one of the above items. 6. A method for forming a TiN film according to any one of claims 1 to 5, in forming a TiN film in the manufacture of an electronic component including a TiN film as a constituent element. Manufacturing method of electronic components.