JP3058053B2 - Method of forming aluminum thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an aluminum thin film in a semiconductor device and a display device, and more particularly to a method for forming a wiring having an interlayer connection.

[0002]

2. Description of the Related Art High density and high integration of semiconductor integrated circuits and display devices are supported by fine processing technology. In the process of forming the aluminum thin film for wiring, instead of the conventional sputtering method, vapor deposition method, etc., gas phase chemical growth (CV) having excellent step coverage is adopted.
Method D) is about to be applied.

[0003] As a conventional method of forming an aluminum thin film, for example, a literature (Appl. Phys. Lett. No. 57, No. 1221)
Page, 1990), the aluminum was selectively deposited only in the connection holes by chemical vapor deposition ("CVD"), and then excited by high-frequency plasma. There is a method of irradiating a substrate with a source gas to form an Al film serving as a wiring layer on the entire surface of the substrate. That is, referring to FIG. 2, after selectively depositing the second aluminum film in the contact hole (contact hole) by the CVD method (see FIG. 2).
(See FIG. 2B), and irradiate the substrate with a source gas (eg, Al (CH ₃ ) ₂ H) 9 containing aluminum excited by high-frequency plasma (see FIG. 2C), and interconnect the entire surface of the substrate by a batch CVD method. A third aluminum film 8 serving as a layer is formed.
(D)).

[0004]

However, in the above-described conventional example, an expensive high-frequency plasma apparatus is required for switching between the selective CVD and the batch CVD. Further, the size of the aluminum thin film forming apparatus increases, so that the occupied area of the floor increases. Due to these, there is a problem that the manufacturing cost of the semiconductor device and the display device increases.

Accordingly, the present invention has been made to solve the above problems, and to provide a method of forming an aluminum thin film in which a connection hole is filled with aluminum and an aluminum thin film serving as a wiring layer is realized by switching between selective CVD and batch CVD. Aim.

[0006]

To achieve the above object, according to an aspect of the present invention, a silicon oxide film or Si ₃ N ₄ Tona
That in the step of the insulating film in the connection hole to form an aluminum film on the opened substrate to form only the first aluminum film connection hole by chemical vapor deposition method using a raw material containing (a) aluminum Process and (b) Ti [N (C
H ₃ ) ₂ ] ₄ , exposing the substrate to Ti [N (CH)
₃ ) a step of adsorbing ₂ ] ₄ on the substrate surface, and (c) (CH
₃₎ to provide a method of forming an aluminum thin film characterized in that it comprises a step of forming a second aluminum film by chemical vapor deposition using a 2 _AlH.

[0007] The present invention is preferably characterized in that an amine adduct of aluminum hydride AlH ₃ is used as the raw material containing aluminum.

Further, the present invention preferably provides an amine adduct of the aluminum hydride AlH ₃ as AlH ₃ N (C
_{H 3) 3, AlH 3 N} (C 2 H 5) 3, AlH 3 N (CH 3) 2 (C 2 H 5), AlH 3 N (C 3 H 7)
_{3, AlH 3 N (C 4} H 9) 3, N (CH 3) 3 AlH 3 N (CH 3) 3, N (C 2 H 5) 3 AlH 3 N
(C ₂ H ₅ ) ₃ , N (CH ₃ ) ₂ (C ₂ H ₅ ) AlH ₃ N (CH ₃ ) ₂ (C ₂ H ₅ ), N (C ₃ H ₇ ) ₃ A
At least one selected from the group consisting of lH ₃ N (C ₃ H ₇ ) ₃ and N (C ₄ H ₉ ) ₃ AlH ₃ N (C ₄ H ₉ ) ₃ is used.

Further, the present invention preferably provides the above-mentioned raw material containing gasified aluminum, wherein R1 is composed of aluminum, an independent alkyl group or olefin hydrocarbon R1, R2, R3 and hydrogen H. _n
AlH _3-n (n ≦ 3, n is a positive integer), R1 _n R2 _m Al
H _3-nm (n, m ≦ 2, n + m ≦ 3, n and m are positive integers), a molecule having at least one structure selected from the group consisting of R1R2R3Al, and / or a mixture of these molecules. Features.

The present invention preferably provides Al (CH ₃ ) ₃ , Al (C ₂ ) as a gas composed of an alkyl group or olefin hydrocarbons R 1, R 2, R 3 and hydrogen H each independently of the aluminum. _{H 5) 3, Al (CH} 3) 2 H, Al (iC
_{4 H 9) 3, Al (} nC 3 H 7) 3, Al (nC 4 H 9) 3, Al (C 2 H 5) 2 H, Al (i-
C ₄ H ₉ ) At least one selected from the group consisting of ₂ H is used.

In the present invention, preferably, the metal element of the gas to be exposed is 4A, 5A, 6A, 8, 1B, 2
It belongs to at least one of the B and 3B groups.

Further, in the present invention, preferably, the metal element of the gas to be exposed is Ti, Zr, Hf, V, Nb,
Ta, Cr, Mo, W, Co, Ni, Pd, Pt, C
and at least one selected from the group consisting of u, Au, Zn, In, and Ge.

In the present invention, preferably, the gas to be exposed is TiCl ₄ , Ti [N (CH ₃ ) ₂ ] ₄ , W (CO) ₆ , Au (CH ₃ )
₂ (C ₅ H ₇ O ₂ ) and (C ₅ H ₅ ) CuP (C ₂ H ₅ ) ₃ .

[0014]

The principle and operation of the present invention will be described below.

In the present invention, the connection hole opened in the insulating film on the substrate surface is filled with aluminum by a selective CVD method.

Next, 4A, 5A, 6A,
The substrate is exposed to a gas containing a metal belonging to Group 8, 1B, 2B, or 3B. Thereby, the gas is adsorbed on the substrate surface.

Subsequently, the inside of the reaction vessel is evacuated. An adsorption layer of the gas is formed on the surface of the substrate. The adsorption layer depends on the pressure during evacuation and the substrate temperature, but is usually a thin layer of about one atomic layer.

Although the structure and properties of the adsorbing layer differ depending on the material and structure of the underlayer, SiO ₂ , Si ₃ N ₄ , Al, Cu
The inventor has newly found that the gas adsorbed on the above has the same effect on the CVD of aluminum, and when the CVD of aluminum is subsequently performed again, an aluminum thin film is deposited on the entire surface of the substrate. .

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view for explaining a manufacturing method according to one embodiment of the present invention in the order of steps. The present embodiment illustrates a case where the present invention is applied to a wiring process in a silicon integrated circuit.

FIG. 1A shows a substrate having a structure before forming a connection hole, formed by using a standard integrated circuit manufacturing method. In FIG. 1A, reference numeral 1 denotes a silicon substrate, and 2 denotes a first substrate.
Is a first aluminum film, 4 is a second silicon oxide film, and 5 is a titanium nitride film.

Subsequently, as shown in FIG. 1B, a second aluminum film 6 is formed on the entire surface of the silicon substrate 1 by vapor phase chemical growth using (CH ₃ ) ₂ AlH. As a result, the connection holes are filled with the second aluminum film 6. (CH ₃ ) ₂ AlH is bubbled with hydrogen gas at a flow rate of 300 sccm and introduced into the reaction chamber for 5 minutes. The chemical vapor deposition conditions are a substrate temperature of 130 ° C. and a total pressure of 1 Torr.

Next, after the introduction of (CH ₃ ) ₂ AlH is interrupted and the CVD chamber is evacuated, Ti [N (CH ₃ ) ₂ ] ₄ is introduced. The pressure in the reaction chamber is 1 mTorr.

Then, as shown in FIG. 1C, an adsorption layer 7 is formed on the second insulating film 4 and the second aluminum film 6.

Further, after evacuating the CVD chamber, (CH ₃ ) ₂ A
When lH is introduced under the same conditions as above, the third
Was deposited (see FIG. 1D).

In this embodiment, TiN is used as the material of the bottom of the connection hole.
Although the case where is used is illustrated, the same effect can be obtained by using another barrier metal such as TiW or a lithography reaction prevention film such as polycrystalline Si.

Further, the case where the silicon oxide film is used as the insulating film has been exemplified, but the same effect can be obtained by using Si ₃ N ₄ .

Al (CH) is used as an aluminum CVD gas.
₃₎ a case has been exemplified with _{2 H, Al (CH 3)} 3, Al (C
_{2 H 5) 3, Al (} iC 4 H 9), Al (nC 3 H 7) 3, Al (nC 4 H 9) 3, Al (C 2
Aluminum and an alkyl group or olefin hydrocarbon R each independently of aluminum, represented by H ₅ ) ₂ H and Al (iC ₄ H ₉ ) ₂ H;
R1 _n AlH _3-n composed of 1, R2, R3 and hydrogen H
(N ≦ 3, n is a positive integer), R1 _n R2 _m AlH
Similar effects can be obtained by using a molecule having a structure of _3-nm (n, m ≦ 2, n + m ≦ 3, n and m are positive integers), R1R2R3Al, or a mixture of these molecules.

Further, AlH ₃ N (CH ₃ ) ₃ , AlH ₃ N (C ₂ H ₅ ) ₃ ,
_{3 N (CH 3) 2 (} C 2 H 5), AlH 3 N (C 3 H 7) 3, AlH 3 N (C 4 H 9) 3, N (CH 3)
₃ AlH ₃ N (CH ₃ ) ₃ , N (C ₂ H ₅ ) ₃ AlH ₃ N (C ₂ H ₅ ) ₃ , N (CH ₃ ) ₂ (C ₂ H ₅ ) A
lH ₃ N (CH ₃ ) ₂ (C ₂ H ₅ ), N (C ₃ H ₇ ) ₃ AlH ₃ N (C ₃ H ₇ ) ₃ , N (C ₄ H ₉ ) ₃ Al
_{H 3 N (C 4 H 9} ) 3 aluminum hydride AlH _3, including
The same effect can be obtained by using the amine adduct of the above.

Further, the case where Ti [N (CH ₃ ) ₂ ] ₄ is used as a gas for switching from the selective CVD to the batch CVD has been exemplified.
Including Cl ₄ , W (CO) ₆ , Au (CH ₃ ) ₂ (C ₅ H ₇ O ₂ ), (C ₅ H ₅ ) CuP (C ₂ H ₅ ) ₃ , the metal elements are Ti, Zr, Hf, V, N
b, Ta, Cr, Mo, W, Co, Ni, Pd, Pt,
The same effect can be obtained by using a gas of Cu, Au, Zn, In, or Ge. Further, similar effects can be obtained if the metal element of the gas to be exposed belongs to the group 4A, 5A, 6A, 8, 1B, 2B, 3B.

Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, but includes various embodiments according to the principle of the present invention.

[0032]

As described above, according to the present invention,
The connection holes are filled with aluminum, and the aluminum thin film serving as the wiring layer can be realized by a simple method of exposing to a gas containing a metal, so that an expensive and large-sized device is not required and a complicated manufacturing process is not required. Therefore, there is an effect that the manufacturing cost of the semiconductor device and the display device can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining main steps of an embodiment of the present invention in the order of steps.

FIG. 2 is a view showing a conventional process.

[Explanation of symbols]

 Reference Signs List 1 silicon substrate 2 first silicon oxide film 3 first Al film 4 second silicon oxide film 5 TiN film 6 second Al film 7 adsorption layer 8 third Al film 9 source gas

Claims (1)

(57) [Claims] 1. A silicon oxide film or _Si 3 _{N 4} Tona
That in the step of the insulating film in the connection hole to form an aluminum film on the opened substrate to form only the first aluminum film connection hole by chemical vapor deposition method using a raw material containing (a) aluminum (B) exposing the substrate to Ti [N (CH ₃ ) ₂ ] ₄ ,
A process for adsorbing the Ti [N (CH ₃ ) ₂ ] ₄ on the substrate surface
And (c) forming a second aluminum film by a vapor phase chemical growth method using (CH ₃ ) ₂ AlH .