JPH0718450A - Formation of thin film - Google Patents

Abstract

PURPOSE:To send a stabilized mist to a film forming chamber and consequently to form a thin film having a desired characteristic with good reproducibility. CONSTITUTION:The crystal powder 12 of a molecular compd. consisting of plural moleculaes which are thermally decomposed and further enter into reaction is previously spread over the surface of a substrate 17, the substrate 17 is heated by a heater 19 to heat and thermally decompose the powder 12, and the decomposed molecules are allowed to react with one another to form a thin film on the substrate 17 surface. A compd. consisting of at least water of crystallization and a metal oxide is appropriately used as the molecular compd. to be used as the raw material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin film such as a thin film resistor by thermally decomposing a molecular compound composed of a plurality of molecules that react with each other on the surface of a substrate and further reacting the compound.

[0002]

2. Description of the Related Art A high resistance thin film resistor such as a cermet film is usually formed by a sputtering method. But,
Since the sputtering method forms a film in a vacuum, expensive equipment is required, and there is a problem that the cost increases when forming a film in a large area. Therefore, an attempt has been made to form a film by a chemical atomization deposition method (CMD method) in which a raw material solution is atomized, and this is applied to a heated substrate to form a thin film on the surface of the substrate.

FIG. 2 shows such a chemical atomization deposition method (C
It is an example of an apparatus for forming a thin film by the MD method). Here, the raw material solution is stored in the raw material atomization container 1, and the raw material solution is atomized in the raw material atomization container 1 by the ultrasonic transducer 2 provided at the bottom of the raw material atomization container 1. On the other hand, the film forming chamber 4 is housed in the exhaust container 3, and the mist introducing port 9 is provided above the film forming chamber 4. A thin film is formed on the surface of the substrate 5. The substrate 5 is held on the susceptor 6 at the bottom of the film forming chamber 4, and the heater 7
Is heated to a predetermined temperature.

A pipe for supplying a carrier gas such as nitrogen gas and a mist supply pipe connected to the mist introduction port 9 of the film forming chamber 4 are connected to the raw material atomization container 1, and are shown by arrows. In this way, when carrier gas is sent to the raw material atomization container 1,
The fog generated there is sent to the film forming chamber 4. This mist is sent out below the film forming chamber 4, contacts the surface of the substrate 5, reacts with oxygen and water vapor, and forms a thin film there. The mist or carrier gas that has not formed a thin film exits from below the film forming chamber 4 and is exhausted from the exhaust container 3 through the damper 8.

[0005]

[Problems to be Solved by the Invention]
When forming a thin film by the chemical atomization deposition method (CMD method), the characteristics of the obtained thin film are the concentration of the raw material solution, the diameter of the fog particles, the atomization amount of the raw material solution, the flow rate of the carrier gas, and the substrate. It is determined by the surface temperature and the like, and unless these are in a predetermined state, a thin film having desired characteristics cannot be formed with good reproducibility. In particular, when the mist is sent to the film forming chamber 4 by the carrier gas, the temperature and humidity of the carrier gas are extremely important.

However, it is difficult to strictly control the humidity of the carrier gas. Therefore, the present invention is
In view of the above problems, it is an object of the present invention to provide a thin film forming method capable of sending a stable mist to a film forming chamber and capable of forming a thin film having desired characteristics with good reproducibility.

[0007]

[Means for Solving the Problems] That is, in order to achieve the above-mentioned object, in the present invention, a molecular compound composed of a plurality of components which are thermally decomposed and reacted under high heat is thermally decomposed on the surface of a substrate and reacted. A thin film forming method for forming a thin film on a substrate, characterized in that a crystal powder of the molecular compound is spread on the surface of the substrate, and the crystal powder is heated on the surface of the substrate for thermal decomposition and reaction. A method of forming a thin film is provided. In this case, the crystal powder of the molecular compound is preferably made of a compound containing at least crystal water and a metal chloride.

[0008]

[Operation] In the thin film forming method according to the present invention, among molecular compounds laid on the surface of a substrate, that is, compounds in which two or more kinds of stable molecules are directly bonded to each other, those which can be decomposed into original components relatively easily The crystalline powder is pyrolyzed at high temperature. By selecting a compound in which the decomposed molecules or atmosphere react with each other at a high temperature to form a film, a thin film can be formed on the substrate as in the CMD method. In particular, when forming a metal oxide thin film to be a resistor, by selecting a compound containing water of crystallization and metal chloride, the metal chloride in the fine powder is separated at high temperature,
Oxygen in the crystal water reacts with the metal to easily form a metal oxide thin film.

In such a method, since no solvent is used, the characteristics of the formed thin film can be prevented without being affected by the heat of vaporization taken from the substrate due to the evaporation of the solvent. In addition, when the resistance value of the thin film is to be increased by doping the thin film with impurities, the diameter of the impurity powder to be introduced can be freely selected by mixing the impurity powder with the crystal powder. Therefore, a high-resistance thin film resistor can be obtained.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an example of a device for carrying out the present invention. As shown in this figure, the substrate 17 on which a thin film is to be formed is held on the susceptor 18 at the bottom of the film forming chamber 16 and heated from below by a heater 19 to a predetermined temperature. Gas such as water vapor generated in the film forming chamber 16 is exhausted through the damper 21.

In the present invention, using such a thin film forming apparatus, crystal powder 12 of a molecular compound composed of a plurality of molecules which are thermally decomposed at a high temperature and further reacted.
Is spread in advance on the surface of the base 17, and the base 17 is heated by the heater 19 to heat the crystal powder 12,
This is thermally decomposed and the decomposed molecules are reacted with each other to form a thin film on the surface of the base 17.

The crystal powder 12 of the molecular compound should not be spread over the surface of the base 17 in advance, and the crystal powder should be uniformly dispersed on the surface of the base 17 which has been heated to a predetermined temperature to form a thin film. You can also The molecular compound used as the raw material is
Preference is given to compounds which consist at least of water of crystallization and metal chlorides.

Next, a more specific embodiment of the present invention will be described. (Example 1) SnCl ₄ .5 having an average particle size of about 100 μm
Prepare a fine powder of H ₂ O, spread it evenly on a glass substrate, put the substrate in a heating furnace, and heat it at about 500 ° C for 5 hours.
Heated for minutes. As a result, a SnO ₂ thin film having a sheet resistance value of 1 kΩ / □ was formed. Further, the SnCl ₄ ·
By using the fine powder of the molecular compound shown in Table 1 instead of the fine powder of 5H ₂ O, the thin films shown in Table 1 can be formed by the same method as described above.

[0014]

[Table 1]

(Example 2) S having an average particle size of about 100 μm
to a fine powder of nCl ₄ · 5H ₂ O, an average particle diameter of about 100μm
The fine powder of Sb of was uniformly mixed at the ratio shown in Table 2, and this was uniformly spread on a glass substrate, and then the substrate was placed in a heating furnace and heated at about 500 ° C. for 5 minutes. As a result, Sb-doped SnO ₂ thin films having resistance values shown in Table 2 were formed.

[0016]

[Table 2]

Further, instead of the fine powder of Sb, In
_{Cl 3 · 4H 2 O, NF} 4 F: HF, FeCl 3 · 6H 2 O
The fine powder of was mixed to form a thin film. As a result, it was possible to obtain thin films having different resistance values depending on the mixing ratio.

[0018]

As described above, the present invention provides a thin film forming method capable of eliminating the influence of heat of vaporization associated with the evaporation of a solvent, thereby forming a thin film having desired characteristics with good reproducibility. Can be provided.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of an example of an apparatus for carrying out a thin film forming method which is an embodiment of the present invention.

FIG. 2 is a schematic system diagram of a thin film forming apparatus for performing a conventional thin film forming method.

[Explanation of symbols]

 12 Fine powder of molecular compound 16 Film forming chamber 17 Substrate 18 Susceptor 19 Heater

Front Page Continuation (72) Inventor Takashi Ishiguro 6-16-20 Ueno Taito-ku, Tokyo Taiyo Induction Co., Ltd.

Claims (2)

[Reference number] 050234-01 [Claims] 1. A thin film forming method for forming a thin film on a substrate by thermally decomposing a molecular compound consisting of a plurality of components which decompose under high heat and react with each other on the surface of the substrate, and further forming a thin film on the substrate. 2. A method for forming a thin film, characterized in that a crystal powder of the molecular compound is spread on the surface of, and the crystal powder is heated on the surface of the substrate for thermal decomposition and reaction. 2. The thin film forming method according to claim 1, wherein the crystal powder of the molecular compound comprises a compound containing at least crystallization water and a metal chloride.