JPH07273052A - Cvd device - Google Patents

Abstract

PURPOSE:To obtain a CVD device having no need of using a TEOS carburetor as a separate unit by providing a carbureretting means of liquid TEOS inside the upper part electrode. CONSTITUTION:An upper part electrode 40 has a hollow metallic electrode plate 42. An enlarged hollow part of the metallic electrode plate 42 is provided with a liquid TEOS caburetting means 52. An axial central part of carburetting means is a vaporizing surface 54 and a liquid TEOS dropping pipe 58 is provided facing to the vaporizing surface 5. Liquid TEOS dropped from the dropping pipe 58 on the vaporizing surface 54 is carburetted in an instant to become gaseous. Carburetted and gasified TEOS goes through a carrier gas-feeding pipe 46 and a gas introduction path 44 for being diffused by carried gas such as N2 or He blown down toward the vaporizing surface 54 so as to flow from an opening part 60 of the caburetting means 52 toward the upper part of a shower electrode 32. This constitution makes a separate unit of the carburetor of TEOS unrequired.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a CVD apparatus. More specifically, the present invention relates to a novel plasma CVD apparatus using tetraethyl orthosilicate (TEOS).

[0002]

2. Description of the Related Art In the manufacture of semiconductor ICs, there is a step of forming a thin film of silicon oxide on the surface of a wafer. Chemical vapor deposition (CVD) is used as a method of forming a thin film. There are three CVD methods, an atmospheric method, a decompression method and a plasma method, but the plasma method is attracting attention as a suitable method for a recent ultra LSI that requires a high quality and highly accurate thin film. .

In the plasma method, a high-frequency voltage is applied to a reaction gas injected in a vacuum to form a plasma, and energy required for the reaction is obtained. Therefore, a uniform film thickness and a good film quality can be obtained. Moreover, it is excellent in many respects such as a high film formation speed.

For example, SiH ₄ or the like has been used as a material for forming a silicon oxide film by the plasma method, but with the miniaturization of semiconductor devices, reduction in step coverage has become a problem. Instead of this monosilane gas,
Recently, liquid tetraethyl orthosilicate (TEO
S) [Si (OC ₂ H ₅ ) ₄ ] has come into use. This is because TEOS can form a dense film having excellent step coverage. When a silicon oxide film is formed using TEOS, TEOS is heated and vaporized,
TEOS gas is used, which is mixed with oxygen gas and supplied to the reaction furnace.

FIG. 2 shows a conventional plasma C using TEOS.
It is a schematic diagram of a VD device. As shown in FIG. 2, a constant temperature bath 1 maintained at about 40 ° C. to 80 ° C. by a heater 12
1 is provided with a container 13 accommodated therein, and the liquid T
EOS 14 is filled to the proper height. When the tip of the pipe 15 is inserted into the filled liquid and the carrier gas of nitrogen gas (N ₂ ) or helium gas (He) is blown, the liquid TEOS is vaporized, and this is contained in the bubbles of the carrier gas, and is higher than the liquid surface. Diverge. The dispersed TEOS gas is taken out together with the carrier gas through the take-out pipe 16 into the reaction furnace 30.
Be delivered to. In order to prevent the vaporized TEOS from cooling and liquefying again, a heater tape 23 is wound around the pipe 16 and an appropriate electric current is passed through the heater tape 23 to maintain the temperature of the reaction gas at a constant value. The amount of TEOS supplied is determined by a mass flow controller (MF) installed in the middle of the pipe 15.
C) Controlled by 17. The reaction furnace 30 has an airtight structure and has a vacuum inside, and the reaction gas is sprayed from the shower electrode 32, converted into plasma by a high frequency voltage applied by a high frequency power source (not shown), and the wafer 4 to be processed placed on the susceptor 33. A thin film is formed on. The reaction-treated gas is discharged from the exhaust port 34 to an exhaust gas processing unit provided outside.

As described above, in the conventional device, TEOS is used.
The carburetor of No. 2 is a separate unit, and there are drawbacks that not only the entire apparatus becomes large, but also the manufacturing cost of the apparatus itself becomes high. Further, it is necessary to control the temperature until the vaporized TEOS is sent to the shower electrode of the reaction furnace. Furthermore, there is a concern that vaporized TEOS will be liquefied again before reaching the shower electrode.

[0007]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a new CVD apparatus which does not require the TEOS vaporizer to be used as a separate unit.

[0008]

In order to solve the above problems, the present invention has a reaction chamber, a susceptor for mounting and heating a wafer in the reaction chamber, and a susceptor facing the susceptor. In a CVD apparatus having an upper electrode, the upper electrode is connected to a high frequency power source, and a minute penetrating contact is made with a hollow metal electrode plate having a gas introduction passage therein and a lower end peripheral surface of the metal electrode plate. A shower electrode having a large number of holes, heating means is provided in the hollow portion of the metal electrode plate, and a TEOS supply pipe for dropping liquid TEOS is provided on the upper surface of the heating means. A CVD apparatus characterized by the above.

[0009]

As described above, according to the apparatus of the present invention, since the vaporizing means for the liquid TEOS is provided inside the upper electrode, the pipe and the temperature adjusting means for transporting the gasified TEOS as in the conventional apparatus. Becomes unnecessary. Also, the problem of reliquefaction of TEOS after vaporization is eliminated. Further, since the conventional TEOS vaporization unit is not provided, not only the entire apparatus becomes smaller, but also the manufacturing cost of the apparatus can be reduced.

[0010]

The present invention will be described in more detail with reference to specific examples.

FIG. 1 is a schematic diagram of an example of the CVD apparatus of the present invention. As shown in FIG. 1, the upper electrode 40 has a hollow metal electrode plate 42. A gas introduction path 44 is provided in the upper portion of the metal electrode plate 42, and a feed pipe 46 for a carrier gas (for example, N ₂ or He) is provided at an appropriate position near the upper end of the gas introduction path 44. It is connected. Further, a connection cable terminal 50 connected to the high frequency power source 48 is provided at the upper end of the gas introduction path 44. Liquid TEOS vaporizing means 52 is disposed in the enlarged hollow portion of the metal electrode plate 42. A central portion in the radial direction of the vaporizing means 52 is an evaporation surface 54, and a resistance heating type heater 56 such as a nichrome wire exists below the evaporation surface 54. Although not shown, this heater is connected to an external power source. If necessary, this heater can be connected to a suitable temperature controller, and the temperature of the evaporation surface 54 can be controlled by the temperature controller. Facing the evaporation surface 54,
A liquid TEOS dripping pipe 58 is provided. The liquid TEOS dropped from the dropping pipe 58 onto the evaporation surface 54 is instantly vaporized by the heated evaporation surface 54 and becomes a gas. The vaporized and gasified TEOS is diffused by the carrier gas such as N ₂ or He blown down toward the evaporation surface 54 through the carrier gas supply pipe 46 and the gas introduction passage 44, and the TEOS of the vaporizer 52 is used. Shower electrode 3 from opening 60
It flows toward the upper surface of 2.

The amount of gaseous TEOS can be changed by the amount of TEOS dropped and evaporated. Liquid TEO
The drop amount of S is controlled by a mass flow controller (MFC) 62 provided in the middle of the drop pipe 58.

Although only one dropping port for the liquid TEOS is provided in FIG. 1, it is not limited to this mode. A plurality of evaporating surfaces 54 may be provided in accordance with the size of the evaporating surface 54, or microscopic holes provided in the spiral tube may be dropped on the evaporating surface like rain.

The metal electrode plate 42 and the shower electrode 32 are covered with an insulating ring 64 to form the upper electrode 40. The constituent material of the insulating ring 64 is not particularly limited. Any material can be used as long as it can achieve the purpose of insulating and holding the high frequency electrode.

The constituent material of the liquid TEOS vaporizing means 52 is not particularly limited. Either conductive or insulating materials can be used. Metal materials with high thermal conductivity are preferred. Inorganic materials such as ceramics are also suitable. The surface of the evaporation surface 54 can be coated with a film such as Teflon, if desired.

Although the apparatus of the present invention has been described above in terms of liquid TEOS and plasma CVD apparatus, the organic source usable in the present invention is not limited to TEOS, and all other known organic sources can be used. it can. Further, the apparatus itself is not limited to the plasma CVD apparatus, and can be similarly applied to atmospheric pressure and reduced pressure CVD apparatuses. It can also be carried out for all gas phase reactors using a liquid organic source.

[0017]

As described above, in the CVD apparatus of the present invention, liquid TEOS vaporizing means is built in the upper electrode. As a result, the gasified TE as in conventional equipment
Piping and temperature control means for transporting the OS are unnecessary. Also,
The problem of TEOS reliquefaction after vaporization is eliminated. Further, since the conventional TEOS vaporization unit is not provided, not only the entire apparatus becomes smaller, but also the manufacturing cost of the apparatus can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of a CVD apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of an example of a conventional CVD apparatus having a vaporizer unit for a liquid organic source such as TEOS as a separate unit.

[Explanation of symbols]

 4 Wafer 11 Constant Temperature Chamber 12 Heater 13 Container 14 Liquid TEOS 15 Pipe 16 Extraction Pipe 17 Mass Flow Controller 23 Heater Tape 30 Plasma CVD Reactor 32 Shower Electrode 33 Susceptor 34 Exhaust Port 40 Upper Electrode 42 Metal Electrode Plate 44 Gas Introducing Path 46 Transfer Gas supply pipe 48 High-frequency power supply 50 High-frequency power supply connection terminal 52 Liquid TEOS vaporization means 54 Evaporation surface 56 Heater 58 Liquid TEOS dropping pipe 60 Vaporization means opening 62 Liquid TEOS mass flow controller 64 Insulation ring

Claims (4)

[Claims] 1. A CVD apparatus having a reaction chamber, a susceptor for placing and heating a wafer in the reaction chamber, and an upper electrode facing the susceptor, wherein the upper electrode is a high frequency power source. The metal electrode plate is connected and has a hollow metal electrode plate inside, and a shower electrode provided with a large number of minute through holes that come into contact with the lower end peripheral surface of the metal electrode plate. Liquid TEO is placed in the hollow part of the electrode plate.
S vaporization means is provided, and liquid TEO is provided on the upper surface of the vaporization means.
A CVD apparatus characterized in that a TEOS supply pipe for dropping S is provided. 2. The liquid TEOS vaporizing means has an evaporation surface, the outlet of the liquid TEOS supply pipe faces the evaporation surface, and the vaporizing means has a heater built in below the evaporation surface. 1. CVD equipment. 3. The CVD apparatus according to claim 1, wherein the liquid TEOS vaporizing means has an opening for blowing down the vaporized gaseous TEOS onto the upper surface of the shower electrode. 4. The CVD apparatus according to claim 3, wherein the gaseous TEOS vaporized by the liquid TEOS vaporizing means is diffused by the carrier gas introduced from the gas introduction passage and blown down onto the upper surface of the shower electrode.