JPH08176830A - Thermal CVD equipment - Google Patents

Abstract

(57) [Summary] [Object] To provide a thermal CVD apparatus having high film formation efficiency regardless of the size and shape of a substrate. [Structure] An internal reactor is further provided in the film formation reaction chamber, and the substrate is placed in the internal reactor. The internal reactor is made according to the size and shape of the substrate, and is made of a substance having good adhesion to the film. Since the space that is substantially involved in the reaction is limited, the reaction gas stays around the substrate, the thermal efficiency of the heater is improved, and the film formation efficiency is significantly improved. At the same time, it is possible to prevent contamination due to peeling of the film formed on the inner wall of the reaction chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CVD (Chemical Vapor Deposition) apparatus for forming a film of metal, ceramics or the like on the surface of a substrate by a chemical reaction of a reaction gas, and in particular, it uses heat as the excitation energy of the reaction. The present invention relates to a thermal CVD apparatus utilizing

[0002]

2. Description of the Related Art CVD technology is used for material diversity, high purity,
It is a practical technology that has the advantage of good controllability and is widely used in the manufacture and coating of various devices. However, due to its potential, it is still a developing technology and is in the process of being optimized. In particular, the technique for producing a high-melting-point metal film is indispensable for the production of target materials, LSIs, etc., and is drawing attention.

The most basic of CVD techniques is thermal CVD
There is. This uses heat as excitation energy for the reaction and is roughly classified into heating methods. An internal heat type (Fig. 2) having a heating source inside the reaction chamber, and an external heat type (heated from outside the reaction chamber) (Fig. 3), an internal heat + external heat type (Fig. 4) having both of these has been developed.

The basic structure of the thermal CVD apparatus will be described with reference to FIG. A substrate 3 is placed on a support 2 installed in the reaction chamber 1. A reaction gas containing a reaction product is introduced from the reaction gas inlet 4, heated and excited by the heater 5, and a target reaction product film is formed on the substrate 3 which is also heated by the heater 5.

[0005]

In any of the types of the thermal CVD apparatus shown in FIGS. 2 to 4, the film forming ability depends on the heating temperature of the substrate or the reaction gas and the concentration of the reaction gas surrounding the substrate. To do. In order to increase the reaction efficiency, if the reaction chamber is made small by simply thinking, the thermal efficiency is good, and the reaction gas is also efficiently guided to the vicinity of the substrate.

However, although the structure of the reaction chamber is shown as a model in a simple housing in the drawings of the present application, it is actually designed in a complicated manner such as a structure for obtaining airtightness,
In addition, stainless steel, nickel, etc., which are excellent in heat resistance and corrosion resistance, are generally used as materials, and are very expensive. Therefore, it is virtually impossible to recreate the reaction chamber according to the size and shape of the substrate, and the reaction chamber has to be secured to some extent.

Further, even if the reaction chamber is made small,
Certainly, the efficiency of heat and reaction gas increases, but at the same time, the temperature of the wall of the reaction chamber rises, and the film adheres not only to the substrate but also to the inner wall of the reaction chamber. Then, this unexpected product is peeled off and falls onto the substrate and the bottom of the reaction chamber, which deteriorates the quality of the film.
Alternatively, it causes a defect in the exhaust system. In order to prevent such a situation, a method of cooling the wall of the reaction chamber has been developed, but the thermal efficiency is lowered, and the reaction gas is liquefied or adsorbed on the wall of the cooled reaction chamber, and the gas efficiency to the substrate is also lowered. Will end up.

The present invention has been made to solve the above problems, and an object thereof is to provide a thermal CVD apparatus having high reaction efficiency regardless of the size and shape of the substrate.

[0009]

In order to solve the above-mentioned problems, in the thermal CVD apparatus according to the present invention, an internal reactor is further provided inside the reaction chamber, and the substrate is placed in this internal reactor. I am trying.

The term "substrate" as used herein means a Si substrate at the time of making an LSI, tools to be coated,
It refers to all coated materials of unspecified shape and size, such as targets in X-ray generators.

[0011]

According to the above construction, since the internal reactor can be manufactured in accordance with the size and shape of the substrate, there is no waste in the actual reaction space, and the reaction gas exists in a high concentration around the substrate,
The utilization efficiency of the reaction gas is remarkably improved. Further, particularly in the case of an internal heat type or internal heat + external heat type thermal CVD apparatus, the heat from the heater does not diffuse, and the temperature of the reaction gas in the internal reactor and the temperature of the substrate involved in the reaction are increased. The efficiency of film formation against heating is significantly improved. Furthermore, a film, which is a side reaction, is generated on the wall of the internal reactor, but when the internal reactor is made of a material with good adhesion to this film, the film is deposited without peeling and the inside of the reaction chamber In addition to keeping it in a clean state, the quality of the film formed on the substrate is improved and defects can be prevented.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing an embodiment of an internal heat type apparatus of a thermal CVD apparatus according to the present invention. Now, a process of forming a refractory metal film by a reduction reaction of a metal halide with the apparatus of this embodiment will be described as an example.

For example, a case of forming a tungsten (W) film on a substrate by vapor deposition by the CVD method will be described. WF6 (tungsten fluoride) used as a raw material is gasified and introduced from the reaction gas introduction port 4 into the internal reactor 6 provided in the reaction chamber 1. The gas inlet is formed in the shape of a nozzle or a shower so as to diffuse uniformly. A heater 5 is arranged in the internal reactor 6. A known heating method such as electric heating or dielectric heating may be used. Using the thermal energy of the heater 5 as excitation energy, the substrate 3 in the internal reactor 6 and the WF6 gas and H2 gas simultaneously introduced into the reaction chamber are heated and excited, and WF6 is reduced by H2, and the substrate 3 W on top
Is deposited as. Since the exhaust gas contains a toxic substance, it is exhausted from the exhaust port 7 and then treated by a known technique such as a scrubber.

The internal reactor 6 was formed in a cylindrical shape by using a 0.2 mm copper plate which is easy to machine. Since the purpose of providing this internal reactor is to collect heat and gas as much as possible around the substrate, the airtightness of the reaction chamber 1 is not required.

Comparative experiments were carried out between the case where the internal reactor 6 according to the present invention was used and the case where the conventional internal reactor 6 was not used. WF6
The gas was 200 CCM and the H2 gas was 1000 CCM, and they were supplied at normal pressure using a nozzle having an inner diameter of 4 mm. Heater set temperature is 75
Although it is 0 ° C, the actual substrate temperature is raised to 650 ° C in the conventional method, whereas it is raised to 670 ° C in the case of using the internal reactor according to the present invention. Increased by about 40%. Furthermore, the time required to raise the temperature to the above temperature at the same output was reduced to about 2/3.

In the conventional method, a film was formed on the inner wall of the reaction chamber 1, and also according to the present invention, a film was formed on the inner wall of the internal reactor 6. In the conventional method, the strength of the material of the reaction chamber 1 is
Stainless steel, nickel, etc. are generally used due to restrictions such as corrosion resistance, but these materials have poor adhesion with tungsten, peel off and fall, and fall onto the substrate to cause defects, exhaust system Pollutes. On the other hand, according to the present invention, the internal reactor 6 is made of copper,
Since copper has very good adhesion to tungsten, it was deposited without peeling and did not cause defects or contamination.

According to the internal reactor, the internal heat type having a heater in the internal reactor has the highest thermal efficiency, but the external heat type also has
Since the efficiency of the reaction gas can be improved, W
When an expensive gas such as F6 is used, its effect can be expected sufficiently.

Since the film formed in the internal reactor 6 continues to be deposited without peeling off, this internal reactor can be used for a long period of time. The film may be removed by etching or the like after it is deposited to some extent, but the copper plate used as the material may be disposable and replaced because it is inexpensive. On the contrary, when the produced film is an expensive substance such as tungsten, the copper may be removed and the tungsten may be recycled.

[0020]

Since the thermal CVD apparatus according to the present invention is further provided with an internal reactor inside the reaction chamber,
An inexpensive internal reactor can be manufactured according to the size and shape of the substrate without compromising heat resistance and corrosion resistance, and the actual reaction space can be optimized for each substrate, and the utilization efficiency of expensive reaction gas At the same time, the thermal efficiency of the heater could be improved, and as a result, the production rate of the film could be significantly improved. In addition, when the material of the internal reactor is made to have good adhesion to the produced film, the film produced in the internal reactor does not peel off, the reaction chamber can be kept clean, and It is possible to prevent the release film from falling down, prevent defects from occurring, and improve the reliability of the product quality.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an internal heat type of a thermal CVD apparatus according to the present invention.

FIG. 2 is a schematic diagram showing an example of an internal heat type configuration of a conventional thermal CVD apparatus.

FIG. 3 is a schematic diagram showing an example of an externally heated configuration of a conventional thermal CVD apparatus.

FIG. 4 is a schematic diagram showing a configuration example of an internal heat + external heat type of a conventional thermal CVD apparatus.

[Explanation of symbols]

 1 reaction room 2 support 3 substrate 4 reaction Gas inlet port 5: Heater 6: Internal reactor 7: Exhaust port

Claims (2)

[Claims] 1. A heat C comprising a reaction chamber for performing a film forming process on a substrate installed inside, a gas supply unit for supplying a reaction gas into the reaction chamber, and a heating unit for heating the inside of the reactor.
A thermal CVD apparatus, which is a VD apparatus, wherein an internal reactor is further provided in the reaction chamber, and a substrate is arranged in the internal reactor. 2. The thermal CV according to claim 1, wherein the internal reactor is made of a substance having good adhesion to the reaction product.
D device.