JPH06272042A - Formation of thin film - Google Patents

Abstract

(57) [Summary] [Objective] The present invention provides a stable supply of raw material gas,
It is an object of the present invention to provide a method for forming a thin film of an Al-Cu alloy having good controllability of raw material gas. [Structure] The present invention supplies a raw material gas into a reaction vessel,
In a thin film forming method for forming an Al-Cu alloy film by depositing an Al-Cu alloy in a desired region by chemical vapor deposition, the source gas is an organic compound containing both Al atoms and Cu atoms in one compound. It is characterized by using a metal compound.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a chemical vapor deposition method (CV).
The present invention relates to a method for forming an Al-Cu alloy film using the D method), and particularly to wiring used in a semiconductor device.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have changed from LSI to VLS.
The degree of integration has been improved to I and further to ULSI, and along with this, the miniaturization of the width of the wiring and the diameter of the contact hole has been remarkably advanced. In the progress of such technological development, Cu and A have been used as wiring materials for semiconductor devices.
Technology using alloy with 1 (Japanese Patent Laid-Open No. 3-111567, etc.)
Is disclosed. Al-C consisting of Al-Cu alloy film
The u alloy wiring has characteristics that it is superior in flatness and denseness and is resistant to electromigration and stress migration as compared with an Al wiring made of only Al.

Conventionally, such an Al--Cu alloy wiring is CV
In the case of forming by the method D, the raw material gas containing the Al component and the raw material gas containing the Cu component were separately supplied, mixed as they were, and introduced onto the substrate (Japanese Patent Laid-Open No. 2-17).
0419).

[0004]

However, when the alloy film is formed on the substrate by the conventional method, it is necessary to supply the source gas for each metal. Moreover, it is necessary to control the temperatures of the container, the pipes, the pipes, etc. within a specific range according to each raw material gas. Therefore, the supply of the raw material gas becomes unstable, and it is necessary to change the deposition conditions and the like according to each raw material gas. As a result, there are problems that it is difficult to control the raw material gas and that the configuration and control of the CVD apparatus are complicated.

Therefore, an object of the present invention is to provide a thin film forming method that solves such problems.

[0006]

In order to solve the above problems, a source gas is supplied into a reaction vessel, and an Al--Cu alloy is deposited on a desired region by chemical vapor deposition to form an Al-Cu alloy.
In the thin film forming method for forming a —Cu alloy film, an organometallic compound containing both Al atoms and Cu atoms in one compound is used as a source gas.

The organometallic compound preferably has a general formula of (R ₁ R ₂ R ₃ Al) (R ₄ Cu). (In the formula, R ₁ , R ₂ and R ₃ each represent an alkyl group or hydrogen, and R ₄ represents acetylacetonato (acac), trifluoroacetylacetonato (tfac), hexafluoroacetylaceto). Nato (hfac), cyclopentadienyl group (Cp), cyclooctadiene group (COD), tertiary butoxy group (t-C)
₄ H ₉ O).

As these organometallic compounds,
Cyclopentadienyl copper trimethyl aluminum (Cp
CuTMA), cyclopentadienyl copper dimethyl aluminum hydride (CpCuDMAH), cyclopentadienyl copper alane (CpCuAlH ₃ ), hexafluoroacetylacetonato copper trimethyl aluminum ((hfac) CuTMA), hexafluoroacetylacetonato copper dimethyl aluminum hydride ((H
fac) CuDMAH), hexafluoroacetylacetonato copper alane ((hfac) CuAlH ₃ ), acetylacetonato copper trimethylaluminum ((acac)
CuTMA), acetylacetonato copper dimethyl aluminum hydride ((acac) CuDMAH), trifluoroacetylacetonato copper trimethylaluminum ((tfac) CuTMA), trifluoroacetylacetonato copper alane ((tfac) CuAlH ₃ ), tertiary butoxy. Copper trimethyl aluminum ((t-C ₄ H
₉ O) CuTMA) or tertiary butoxy copper alane ((t-
Is _{C 4 H 9 O) CuAlH 3} ) or the like.

In order to solve the above problems, in a thin film forming method of supplying a source gas to form an Al-Cu alloy film by a chemical vapor deposition method, both the Al atom and the Cu atom are used as the source gas. An alloy film forming step of supplying a gas of an organometallic compound contained in the compound and depositing an Al-Cu alloy in a desired region to form an Al-Cu alloy film by a chemical vapor deposition method, and an alloy film forming step After or before, a gas of an organic Al compound is supplied, and a pure Al film forming step of forming a pure Al film by depositing Al in a desired region by a chemical vapor deposition method is performed. To do.

[0010]

According to the above method, when forming an Al-Cu alloy film, a plurality of source gases are not used, but a gas of an organometallic compound containing an Al component and a Cu component in one compound is used. Since this is performed, the controllability of the raw material gas is improved and the raw material gas can be supplied in a stable state. Further, since a single gas containing an Al component and a Cu component is supplied as the source gas, the number of nozzles supplying the source gas can be reduced, and the structure of the CVD apparatus can be simplified. Become.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the accompanying drawings.

A method of manufacturing a semiconductor device according to the first embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG. 1A, a base insulating film 20 is formed on the surface of a Si substrate 10, and the base insulating film 20 is sputtered. The base insulating film 20 is sputtered with Al.
Deposit alloy to a thickness of 300 to 800 nm
The alloy film 31 is formed. Next, the Al alloy film 31 is processed into a predetermined wiring pattern to form the lower layer metal wiring 30.
The wiring pattern is formed by RIE (reactive ion etching) using a chlorine-based gas after forming a resist pattern using an exposure device. Next, as shown in FIG. 1B, an interlayer insulating film 40 is formed on the base insulating film 20 on which the lower metal wiring 30 is formed.
The interlayer insulating film 40 is formed of Si by plasma CVD.
O ₂ is deposited to form a SiO ₂ film, and SOG (Spi
non glass) to form an SOG film,
It is formed by performing heat treatment at a required temperature.
After that, SiO ₂ is deposited again by the plasma CVD method to form a SiO ₂ film.

Next, a photomask is set on the interlayer insulating film 40, a resist pattern is formed using an exposure device, and then RIE is performed using a fluorine-based gas as shown in FIG.
As shown in (c), a via hole 50 is formed in the interlayer insulating film 40. Next, the lower metal wiring 30 exposed at the bottom of the via hole 50 by plasma etching using a chlorine-based gas.
(Al alloy film) is cleaned. This process is performed because deposits, an alumina film and the like adhere to the surface of the lower layer metal wiring 30 exposed at the bottom of the via hole 50 during RIE and when exposed to the atmosphere after RIE. This is because the deposit and the alumina film have to be removed because they impede Al deposition in the CVD method.

Next, Cp which is a raw material of the Cu-Al alloy film is used.
_{CuTMA (C 5 H 5 CuAl (} CH 3) 3: Cycl
open-only-trimethylalu
2 (a) by selectively depositing Al and Cu from the bottom surface only in the via hole 50 by a thermal CVD method using a hydrogen gas (minium-copper) and hydrogen as raw materials.
As shown in FIG. 5, an Al—Cu alloy film is formed and a via plug 51 is formed. The conditions for performing the CVD at this time are as follows: bubbling pressure 500 Torr, hydrogen gas flow rate 100 scc
m, bubbling temperature 80 ° C. The total pressure in the CVD reaction vessel for forming this film was 2 Torr, and the temperature was 270 ° C.
Is.

As the organic compound having a Cu component and an Al component in one compound, such as CpCuTMA, other than this, cyclopentadienyl copper trimethyl aluminum (CpCuTMA), cyclopentadienyl copper dimethyl aluminum hydride (CpCuDMA
H), cyclopentadienyl copper alane (CpCuAlH
₃ ), hexafluoroacetylacetonato copper trimethylaluminum ((hfac) CuTMA), hexafluoroacetylacetonato copper dimethyl aluminum hydride ((hfac) CuDMAH), hexafluoroacetylacetonato copper alane ((hfac) CuAlH)
₃ ), acetylacetonato copper trimethyl aluminum ((acac) CuTMA), acetylacetonato copper dimethyl aluminum hydride ((acac) CuD
MAH), trifluoroacetylacetonato copper trimethyl aluminum ((tfac) CuTMA), trifluoroacetylacetonato copper alane ((tfac) CuA
lH _3), third-butoxy copper trimethylaluminum _{((t-C 4 H 9} O) CuTMA) or tertiary butoxy copper Alan _{((t-C 4 H 9} O) CuAlH 3) , and the like.

When the CVD reaction is performed by supplying a single source gas containing an Al component and a Cu component in this way, a plurality of source gases are not used, so that the controllability of the source gas is improved. The raw material gas can be supplied in a stable state. In addition, CpCuTMA contains Al component and C in one compound.
Since the raw material gas can be supplied with a single nozzle because it contains the u component, the number of nozzles for supplying the raw material gas can be reduced, and the structure of the CVD apparatus is simplified as compared with the conventional CVD apparatus. You will be able to.

Next, 400 to 1 of Al is formed by the sputtering method.
An Al alloy film is deposited to a thickness of 000 nm to form an upper metal wiring 60 as shown in FIG. 2B, using the same method as that used to form the lower metal wiring 30 described above. A semiconductor device having a multilayer wiring structure is manufactured.

By the time the semiconductor device using the via structure of the present invention is completed, a surface protective film is formed after the via plug 51 is formed, and heat treatment for removing process damage is performed.

Further, structures necessary for a semiconductor device such as a diffusion layer and a gate electrode are formed in and on the surface of the Si substrate 10. A contact hole exists at a required position of the base insulating film 20, and a contact structure for connecting the lower metal wiring 30 and the diffusion layer or the gate electrode or other structure is formed. If necessary, an antireflection film using W or the like and a barrier metal using TiN or the like are formed between the metal wiring and the insulating film. Further, one or more new interlayer insulating film 40 and metal wiring can be laminated on the upper metal wiring 60. Although the case where the via plug is formed has been described in the present embodiment, the thin film forming method according to the present invention is formed not only by a film for forming a metal wiring but also by a CVD method which is used in another way. It goes without saying that it can also be used when forming a film.

As described above, according to the method of the present invention, the number of nozzles for supplying the raw material gas can be reduced and the structure of the CVD apparatus can be simplified. Therefore, the CVD apparatus used in the present invention will be described below.

FIG. 3 shows the structure of the CVD apparatus used in this embodiment. In the figure, a reaction vessel 310 of a CVD apparatus
A substrate holder 311 holding a substrate 312 is provided therein, and a nozzle 314 is provided on the upper surface of the reaction container 310 so as to face the substrate 312. Each raw material gas described later is supplied through the nozzle 314. A heater 313 is provided inside the substrate holder 311. An AC voltage is applied from the AC power supply 315 to the heater 313 to generate heat and heat the substrate 312 to a constant temperature. The gas exhaust unit 316 exhausts the gas in the reaction container.

The bubbler container 320 is arranged in an oil bath (not shown) whose temperature is controlled, and contains CpCuTMA therein. This bubbler 3
The carrier gas is supplied to 20, and the generated source gas is
From the nozzle 314 to the reaction vessel 3 via the pressure control valve 322.
Supplied within 10.

When the raw material gas is supplied by this apparatus, the pressure inside the bubbler container 320 is controlled to a value equal to or lower than atmospheric pressure. The pressure at this time is selected as an appropriate value depending on the physical properties such as the viscosity of the raw material and the vapor pressure. The temperature of the oil bath is determined in consideration of the thermal stability of the raw material and the vapor pressure.

Next, as a second embodiment of the present invention, a case of forming an via plug by depositing an Al--Cu alloy film on a pure Al film will be described with reference to FIG. The steps other than the via plug forming step are the same as those in the first embodiment.

Next, DMAH (AlH
(CH ₃ ) ₂ : Dimethylalminium h
thermal CVD using hydride gas and hydrogen as raw materials
By selectively depositing Al from the bottom surface only in the via hole 150 by the method, an Al film 151 is formed in the via hole 150 as shown in FIG. C at this time
The VD is performed under a bubbling pressure of 500 Torr, a hydrogen gas flow rate of 100 sccm, and a bubbling temperature of 50 ° C. The total pressure in the CVD reaction vessel for performing this film formation is 2
Torr, the substrate temperature is 250 ° C.

Next, Cp which is a raw material of the Cu--Al alloy film is used.
As shown in FIG. 4B, an Al—Cu alloy film 152 is formed by selectively depositing Al and Cu on the Al film 151 by a thermal CVD method using CuTMA gas and hydrogen as raw materials. . The conditions for performing the CVD at this time are as follows: bubbling pressure 500 Torr, hydrogen gas flow rate 100 sc
cm, bubbling temperature 80 ° C. The total pressure in the CVD reaction vessel for performing this film formation was 2 Torr and the temperature was 270.
℃.

Next, 400 to 1 of Al is formed by the sputtering method.
The Al alloy film is deposited to a film thickness of 000 nm, and the same method as in the case of the first embodiment described above is used.
As shown in (c), the upper layer metal wiring 160 is formed.

Next, after forming the upper metal wiring 160,
Al that constitutes the via plug 153 after annealing treatment
Cu atoms in the Al-Cu alloy film 152 are diffused into the film 151 to be alloyed, and the entire via plug 153 is Al-Cu alloyed as shown in FIG. 4D to form a semiconductor device having a multilayer wiring structure. To manufacture. For action and effect,
There is no difference between the case of the second embodiment and the case of the first embodiment. That is, when a CVD reaction is performed by supplying a single source gas containing an Al component and a Cu component in this way, a plurality of source gases are not used, so that the controllability of the source gas is improved, Gas can be supplied in a stable state.

The structure necessary for the semiconductor device, such as the structure necessary for the semiconductor device such as the diffusion layer and the gate electrode formed in and on the Si substrate 110, is the same as that shown in the above embodiment. Is equipped with.

Similarly, it is also possible to further stack a new interlayer insulating film and a new metal wiring on the upper metal wiring 160, respectively. In addition,
Although the case where the via plug is formed has been described in this embodiment as well, the thin film forming method according to the present invention is used for a film for forming a metal wiring, and is not limited to this and is used for another purpose.
It goes without saying that it can also be used when forming a film formed by the VD method.

[0031]

As described above in detail, according to the present invention, when forming an Al--Cu alloy film, a plurality of source gases are not used, but Al component and C are contained in one compound.
Since the gas of the organometallic compound containing the u component is used, the controllability of the raw material gas is improved and the raw material gas can be supplied in a stable state. Further, as the raw material gas, Al component and C
Since the single gas containing the u component is supplied, the number of nozzles for supplying the raw material gas can be reduced, and the structure of the CVD apparatus can be simplified. As a result, the Al—Cu alloy film can be formed extremely easily as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a diagram showing each manufacturing process of a semiconductor device according to a first embodiment of the invention.

FIG. 2 is a diagram showing each manufacturing process of the semiconductor device according to the first example of the invention.

FIG. 3 is an explanatory diagram of a CVD apparatus used for manufacturing the semiconductor device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing each manufacturing process of the semiconductor device according to the second embodiment of the invention.

[Explanation of symbols]

10, 110 ... Si substrate, 20, 120 ... Base insulating film,
30, 130 ... Lower layer metal wiring, 40, 140 ... Interlayer insulating film, 50, 150 ... Via hole, 151 ... Al film, 51,
152 ... Al-Cu alloy film, 51, 153 ... Via plug, 60, 160 ... Upper layer metal wiring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiichi Kondo 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Technical Research Division (72) Inventor Hiroshi Yamamoto 1 Kawasaki-cho, Chuo-ku, Chiba-shi Address Kawasaki Steel Co., Ltd. Technical Research Division (72) Inventor Yoyo Ota 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Technical Research Division

Claims (3)

[Claims] 1. A thin film forming method for forming a Al—Cu alloy film by supplying a source gas into a reaction vessel and depositing an Al—Cu alloy in a desired region by chemical vapor deposition, wherein the source gas is Is a method for forming a thin film, which uses an organometallic compound containing both Al atoms and Cu atoms in one compound. 2. The organometallic compound has the general formula (R ₁ R ₂ R ₃ Al) (R ₄ Cu) (wherein R ₁ , R ₂ and R ₃ each represent an alkyl group or hydrogen). , R ₄ is acetylacetonato (acac), trifluoroacetylacetonato (tfac), hexafluoroacetylacetonate (h
fac), cyclopentadienyl group (Cp), cyclooctadiene group (COD), tertiary butoxy group (t-C ₄ H)
₉ O). ) The method for forming a thin film according to claim 1. 3. A thin film forming method for forming an Al—Cu alloy film by a chemical vapor deposition method by supplying a raw material gas, wherein an organic metal containing both Al atom and Cu atom in one compound as the raw material gas. An alloy film forming step of forming a Al-Cu alloy film by depositing an Al-Cu alloy in a desired region by a chemical vapor deposition method by supplying a compound gas, and after or before the alloy film forming step. And a pure Al film forming step of depositing Al in a desired region to form a pure Al film by a chemical vapor deposition method.