JPS6176677A - Vapor growth method - Google Patents

Abstract

PURPOSE:To form a dense film having a uniform thickness at a low temp. by irradiating UV rays to an orgl. silane-O2 reactive gas and growing selectively the film on the surface of a material to be treated through the pattern of a mask. CONSTITUTION:Gaseous N2 is introduced into the org. silane in a quartz bubble 10 and is evaporated. The gas is introduced through a flow rate control valve 12 into a reaction vessel 14. The gaseous N2 is introduced into the org. phosphorus in a quartz bubbler 16 and is evaporated. The gas is introduced through a flow rate control valve 18 into the vessel 14. The gaseous O2 is introduced through a flow rate control valve 20 into the vessel 14. The UV rays are irradiated on the surface of a water 26 by an Hg lamp 22 in the vessel 14 to convert part of the gaseous O2 to O3, by which the org. silane is oxidized at <=500 deg.C reaction temp. The film conforming to the pattern of the mask 30 is selectively grown on the wafer 26 when the mask 30 is disposed on the surface of the wafer 26 apart at a slight spacing therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vapor phase growth method, and more specifically, the reaction system is photoexcited by using an organic silane-shin system as a reaction gas source and irradiating ultraviolet rays, and the reaction system is grown at 400°C.
Not only is it possible to perform low-temperature vapor phase growth at a It is about how to grow.

CVD (Chemical Vapor Depot)
The method has been widely put into practical use, such as when forming an insulating protective film on a device where wiring has been completed.

In this case, it would be convenient if the insulating i3j film could be selectively grown in a desired pattern on the surface of the object to be treated.

In the past, for example, a 5iOz film was grown on the entire surface of the object to be treated, and a pattern of the 5iOz film was formed by chemical etching or the like, but this was troublesome and had the disadvantage of increasing the number of steps and increasing costs.

In addition, when forming the above-mentioned insulating protective film, etc.,
In order to protect aluminum wiring and the like from high heat, it is desirable that the reaction temperature be as low as possible (about 40°C).

Conventionally, in order to obtain a high-quality 5ioL film, PSG film, etc. at a temperature of about 400° C., it was necessary to use a 5i)lEOz system or plasma CVD1.

However, in the former case, since the reaction is a thermal decomposition reaction in the gas phase, particles grow in the gas phase, fall, and adhere to the grown film, resulting in so-called particle generation and stenop recovery. It has the disadvantage of poor adhesiveness (uniform adhesion).

In addition, when using the latter plasma CVD method, so-called radiation damage method is used.
This method is not widely used at present because it poses problems such as age) and is not suitable for stenope coverage.

The present invention has been made in view of the above-mentioned difficulties, and its objectives are to enable selective growth of a film easily and reliably, to generate fewer particles, to provide excellent stamp coverage and at low temperatures. The purpose is to provide a new vapor phase growth method that enables the reaction of A suitable mask is placed at a position away from the surface of the object, the reaction temperature is kept at 500°C or less, and the surface of the object to be treated is irradiated with ultraviolet rays to form a film on the surface of the object according to the pattern of the mask. It's about choosing and growing.

Conventionally, in the case of organic silane-based CVD, low-temperature CVD using organic silane systems has been impossible because neither decomposition nor oxidation reactions occur unless the reaction temperature is high, 700"C or higher.

The inventor discovered that each time the organic silane-02-based reaction gas is irradiated with ultraviolet rays, the reaction system is photoexcited ((a part of b becomes 0)), and the oxidation reaction of the organic silane occurs at a low temperature (400°C).
(below) was also found to progress.

Moreover, as a result of experiments, it has been found that the above-mentioned oxidation reaction is mainly a surface reaction that occurs on the surface of the object to be treated. As a result, even if the object to be treated has irregularities, the film grows to a uniform thickness on the concave portions as well as on the convex portions, resulting in an extremely excellent stethoscope coverage method. In addition, since it is a surface reaction, particles grown in the gas phase may fall and adhere to the grown film, or particles that have adhered to the wall of the reaction vessel may fall and adhere to the grown film, unlike conventional methods. Almost no particles are generated (furthermore, the grown film is dense and has few pinholes, and a film with an ideal surface condition can be obtained.

Furthermore, only the portions irradiated with ultraviolet rays are selectively photoexcited, and a film selectively grows only on the surface of the object to be treated in the area irradiated with ultraviolet rays.

Therefore, by using an appropriate mask, a film with a desired pattern can be formed on the surface of the object to be treated. Therefore, the conventional process of chemically etching the 5iOz insulating film, for example, can be omitted, which is extremely useful.

Organic silane (tetraethoxysilane) is a liquid at room temperature, so it is safe to handle.

FIG. 1 is an explanatory diagram showing an outline of the reaction apparatus.

The organic lanthanide is contained in a quartz bubbler 10, and is vaporized in the quartz bubbler 1o using NL gas as a carrier gas.
It is introduced into the reaction vessel 14 via the flow control valve 12.

16 is a quartz bubbler that stores organic phosphorus, and the organic phosphorus is vaporized in the quartz bubbler 16 and sent to the reaction vessel 1 via a flow control valve 18 using NZ gas as a carrier gas.
It will be introduced during 4th. Inorganic phosphorus (PIIA) rather than organic phosphorus
) may be used. Of course, when obtaining a 5iOL film, phosphorous gas is not necessary.

Ol gas is introduced into the reaction vessel 14 via the flow control valve 20.

Reference numeral 22 denotes an Hg lamp, which is placed outside the reaction vessel 14 and irradiates the surface of the wafer 26 placed on the susceptor 24.

A heater 28 heats the susceptor 24 and raises the temperature of the wafer 26 placed on the susceptor 24 to about 400°C.

In this way, each reaction gas is supplied to the reaction vessel 14 via a flow rate control valve.
When the surface of the wafer 26 is irradiated with ultraviolet rays by the 1, l1g lamp 22, a part of the 0□ gas is converted to 01, and the strong oxidizing power of 01 converts the organic silane into 40
It is oxidized even at temperatures below 0°C, and a desired film can be grown.

Further, as shown in FIG. 2, by placing the mask 30 at a position slightly apart from the surface of the wafer 26, the film can be applied to the wafer 26 according to the pattern formed on the mask 30.
6 can be selectively grown. As the material of the mask 30, a material that transmits ultraviolet rays, such as quartz glass, is used.
A pattern for forming a film can be formed by forming a UV-blocking area by chromium vapor deposition or the like and having an UV-transmissive area. A portion of the Oz gas is converted to 03 by the ultraviolet rays transmitted through the transmitting portion, and the film can be selectively grown according to the pattern of the mask 30 mainly due to the surface reaction.

Examples are shown below.

Example 1 Tetraethoxysilane at 80°C, 600CCZ minutes, OL
Gas was introduced into the reaction vessel at a rate of 600 cc/min and N4 gas was introduced as a carrier gas at a rate of 0.82/min, and the wafer was irradiated from outside the reaction vessel with an Hg lamp (wavelength 184.9 nm, 254.Or+m) to maintain the reaction temperature. When the reaction was carried out at 400°C, a 5iO film was obtained at a rate of 1000 per minute.

No particles were observed, and the step strength was good.

Furthermore, when a mask was placed a little distance from the wafer surface and ultraviolet rays were irradiated through the mask, a film could be selectively grown on the wafer according to the pattern of the mask.

Example 2 Under the same conditions as above, organic phosphorus was further introduced into the reaction vessel at a flow rate of 200 cc/min.
Obtained in people/minute.

No particles were observed, and the stenop force was good. Furthermore, we were able to selectively grow a film on the wafer using a mask.

As described above, when using the method of the present invention, by irradiating ultraviolet rays, the organic phosphorus-based reactive gas can be reacted at a low temperature, and by using an appropriate mask, a film can be selectively grown according to the pattern of the mask. be able to. In addition, there is almost no generation of particulates, and the stenop force is also good.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. That's true.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a reaction apparatus, and FIG. 2 is an explanatory diagram showing a case where a film is selectively grown on a wafer using a mask. IO...Quartz bubbler, 12...Flow rate control valve, 14...Reaction container, 16...Quartz bubbler, 18.20...Flow rate control valve. 22...11g lamp, 24...susceptor 12
6...Wafer, 28...Heater. 30...Mask.

Claims (1)

[Claims] 1. Introducing organic silane and O_2 gas into a reaction vessel,
A suitable mask is placed on the object to be processed placed in the reaction vessel at a position separated from the surface of the object to be processed, the reaction temperature is maintained at 500° C. or less, and the surface of the object to be processed is irradiated with ultraviolet rays. A vapor phase growth method characterized by selectively growing a film on the surface of an object to be processed according to the pattern of the mask.