JPS62154617A - Vapor growth apparatus - Google Patents

Abstract

PURPOSE:To form a thin film having uniform thickness on a semiconductor wafer and to reduce the adherence of reactive substance to a wall by injecting second reaction gas which does not form a solid phase by a thermal decomposition together with inert gas through a partition plate above a susceptor. CONSTITUTION:A semiconductor wafer 22 is placed on a susceptor 23, monosilane gas and helium gas as carrier gas are mixed and supplied through a first gas supply port 20 while heating by an infrared ray lamp 30, and oxygen gas and inert gas are fed from a second gas supply port 28. A partition plate 25 disturbs the adherence of reactive substance on the inner wall of a monosilane reaction chamber to form a solid phase by inert gas injected from many flowing holes and thermal decomposition by oxygen gas which does not form a solid phase by thermal decomposition or the reaction with the oxygen gas. Since the oxygen gas is injected from the many holes of the plate 25 on the susceptor 23, the oxygen gas can be supplied uniformly on the wafer 22. Thus, a thin film having uniform thickness with less irregularity of the thickness of the vapor-phase grown film is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vapor phase growth apparatus widely used in the semiconductor industry;
In particular, the present invention relates to a vapor phase growth apparatus for forming vapor phase growth films such as silicon oxide films, silicon nitride films, etc. using two or more types of reactive gases.

Conventional technology Typically, silicon oxide film is used in the semiconductor manufacturing process.

Thin films such as polycrystalline silicon films and silicon nitride films are formed using a vapor phase growth apparatus, particularly a reduced pressure type vapor phase growth apparatus.

Originally, in order to achieve high-volume processing and uniform film thickness, reduced-pressure vapor phase growth equipment was used to arrange a large number of semiconductor wafers upright in a tube-shaped reaction chamber and form thin films in a pressure region where the gas flow was a diffusion flow. was. However, as the diameter of semiconductor wafers to be processed becomes larger, the variation in film thickness becomes larger, and this is particularly noticeable in silicon oxide films whose growth temperature is low. Furthermore, a thin film is similarly deposited on the walls of the reaction chamber, but the apparatus is large and its maintenance is difficult.

Therefore, in recent years, in order to eliminate the above drawbacks, a single-wafer processing type reduced pressure vapor phase growth apparatus as shown in Figure 5 has been devised. , the reaction pressure is increased to the region of viscous flow, and thin films are grown at high speed.

In FIG. 6, reaction chamber A can be completely isolated from the outside air by a quartz belljar 1 and a base plate 2. A gas supply nozzle 3 is connected to one end of the base plate 2, and a gas supply nozzle 3 is connected to the other end of the base plate 2. A gas exhaust port 4 is provided at the. For example, when forming a silicon oxide film on this gas supply nozzle 3,
A monosilane gas supply unit 5, an oxygen gas supply unit 6, and a helium gas supply unit 7 as a carrier gas.
are connected via separate pulps 8. Furthermore, a susceptor 10 on which a semiconductor wafer 9 is placed is installed on the base plate 2 . Further, on the outside of the quartz bell gear 1, an infrared lamp 11 for heating the semiconductor wafer 9 is provided.
A reflecting mirror 12 is attached behind the infrared lamp 11 so that the semiconductor wafer 9 is efficiently irradiated with light from the infrared lamp 11.

Problems to be Solved by the Invention However, in the conventional vapor phase growth apparatus configured as described above, monosilane gas 70 SCCM and oxygen 400 SCCM
SCCM, helium 6SLM reaction temperature 450℃,
As a result of growing a silicon oxide film under normal conditions of pressure eT'orr, as shown in Figure 6, there was a very large variation in film thickness along the gas flow direction, and the film thickness was thinner downstream. There was a tendency to

This tendency of film thickness distribution could hardly be improved even if the growth conditions were changed. Furthermore, the quartz belljar 1 also has a reactive substance attached thereto, which becomes a falling piece and becomes a cause of so-called flakes attached to the semiconductor wafer 9.

In view of the above-mentioned drawbacks, the present invention provides a vapor phase growth apparatus for forming a thin film with good uniformity with less generation of flakes.

Means for Solving the Problems In order to solve the above problems, the present invention provides a reaction chamber having a gas supply port on one end side and a gas discharge port on the other end side, and a reaction chamber provided in the upper part of the reaction chamber. In a vapor phase growth apparatus comprising: an infrared transmitting section, a susceptor provided inside the reaction chamber to support a semiconductor wafer, and an infrared lamp provided above the infrared transmitting section, the gas is supplied to the reaction chamber. An infrared-transmissive partition member is provided to partition the lower chamber having an opening, a gas discharge port, and a susceptor into an upper chamber above the lower chamber, and an appropriate number of communication ports are formed in the partition section by the partition member K, and the lower chamber of the reaction chamber is separated from the upper chamber above the lower chamber. The side gas supply port is used as a supply port for a first reaction gas carrier gas which forms a solid phase by thermal decomposition, and a solid phase is formed by reaction with the first reaction gas in the upper chamber of the reaction chamber, and It is characterized by forming a supply port for a second reaction gas that does not form a solid phase by thermal decomposition or is difficult to thermally decompose, and an inert gas.

Function The present invention has the above-described configuration, and the irradiated light from the infrared lamp is transmitted through the infrared transmitting part of the reaction chamber top plate and the infrared transmitting partition plate to the susceptor in the lower chamber and the semiconductor substrate placed thereon. irradiates and heats them, so that the first
', - A predetermined thin film can be formed on the semiconductor wafer by each of the second reaction gases. In particular, an inert gas and a second reaction gas which does not form a solid phase by itself by thermal decomposition or which is difficult to thermally decompose are jetted downward from the upper chamber into the lower chamber in which the thin film is formed, thereby forming a reaction chamber. The wall surface, especially the infrared lamp side, where the temperature is high and reactants tend to adhere. It is possible to prevent adhesion to the wall surface of the parts other than the bottom, and since the second reaction gas is uniformly supplied from above to the entire surface of the semiconductor wafer placed on the susceptor, it is possible to form a thin film into a uniform film. It can be formed thick.

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

FIG. 1 is a cross-sectional view of a vapor phase growth apparatus according to an embodiment of the present invention, in which a reaction chamber 13 has a wall member 15 made of stainless steel with water cooling grooves 14 provided inside, and a transparent quartz crystal wall member 15 provided in the upper part. It is composed of a top plate 16 consisting of. This top plate 16 is fixed to the wall member 15 via a known gas sealing means such as an O-ring. At one end of the reaction chamber 13, a gas supply unit for a first reaction gas such as monosilane gas and a gas supply unit 18 for a carrier gas such as helium are connected via a valve 191.19□. A gas co-supply port 20 is provided, and the other end is provided with a gas discharge port 21 connected to a vacuum evacuation device such as a rotor+J-pump (not shown). Further, in the lower part of the interior of the reaction chamber 13, a sass holder 23 made of graphite coated with SiC and inked is installed on which a semiconductor wafer 22 is placed. A step portion 24 is provided at the upper part of the wall member 15, and a partition plate 25 having a plurality of gas flow ports 25a made of transparent quartz is located between the susceptor 23 and the top plate 160. 24, the reaction chamber 13 is connected to a gas supply port 20.
Gas outlet 21. It is partitioned into a lower chamber 13a containing the bunabuta 23 and an upper chamber 13b made of soil. Wall member 15
A gas i4-supply unit 26 for a second reaction gas such as oxygen is provided on the side where the gas supply port 20 forming the upper chamber 13b is formed.
A second gas supply port 28 to which a gas supply unit (27) for inert gas such as
is provided. A heating block 29 is installed outside and above the reaction chamber 13 at a position facing the susceptor 23 with the top plate 16 in between. This heating block 29 includes a plurality of rod-shaped infrared lamps 3Q (6
books) are arranged, and a reflecting mirror 31 is arranged on the back of the books.

The operation of the vapor phase growth apparatus having the above configuration will be explained by taking the growth of a silicon oxide film as an example.
A semiconductor Ueno X22 is placed on top of the semiconductor Ueno Oxygen gas and an inert gas (for example, nitrogen) are flowed through 28. At this time, the heat conducted to the wall member 15 is absorbed by the cooling water circulating in the water cooling groove 14, so the top plate 16 of the reaction chamber
Heat accumulation on other walls is prevented. In addition, the partition plate 2S contacts the partition plate 25 with monosilane gas which forms a solid phase through thermal decomposition or reaction with oxygen gas due to inert gas and oxygen gas which do not form a solid phase due to thermal decomposition and inert gas spouted from a large number of flow holes. In order to prevent the adhesion of reactants to the inner wall of the reaction chamber, the oxygen gas is uniformly distributed over the surface of the semiconductor wafer 22 in order to eject the oxygen gas from the numerous flow holes of the partition plate 2S of the susceptor 23'. can be supplied, and a thin film with good uniformity of film thickness with little variation in the thickness of the vapor phase grown film can be obtained.

In the above apparatus, monosilane gas was used.

Flowing helium gas sSLM from the first gas supply port,
400 SCCM of oxygen gas from the second gas supply port.

Supply nitrogen 3SLM, reaction consistency 450°C, pressure 6To
When we attempted to grow a silicon oxide film using rr, the film thickness showed almost no change in the direction of gas flow, as shown in Figure 2, and the uniformity of the thin film was dramatically improved compared to conventional equipment. There was also almost no adhesion of the reactant to the wall member 15 and the partition plate 26.

FIG. 3 shows another embodiment of the present invention in which the partition member is changed, and a round partition rod 32 made of transparent quartz is used as a gas flow port between the susceptor 23 and the top block 1/-) 16.
32a, and the inert gas and the second reaction gas are ejected through the gap 32a. In this case, the interval between the gaps between the partition rods 32 is adjusted according to the film thickness distribution of the thin film grown in the vapor phase on the semiconductor sea urchin/S22. It is possible to further improve the uniformity of

Further, as partition members, transparent quartz horizontal plates 33-1, 33-2, 33-3°33 as shown in FIG.
It may be a multilayer plate 33 in which 1 to 4 are arranged in parallel with each other with a narrow gap between them.

Further, in the present invention, helium gas was used as the carrier gas and nitrogen gas was used as the inert gas, but the combination is not limited to this, and any stable gas that does not participate in the reaction can be used.

Effects of the Invention According to the present invention, a thin film having a uniform thickness can be formed on the surface of a semiconductor wafer by jetting a second reaction gas that does not form a solid phase through thermal decomposition together with an inert gas from above a susceptor through a partition plate. In addition to forming a wall, it is possible to reduce the adhesion of reactants to the wall surface, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a vapor phase growth apparatus according to an embodiment of the present invention, FIG. FIG. 3 is a sectional view of a vapor phase growth apparatus according to another embodiment of the present invention, FIG. FIG. 5 is a sectional view of a conventional vapor phase growth apparatus, and FIG. 6 is a film thickness distribution graph of a semiconductor wafer when a silicon oxide film is formed using the conventional vapor phase growth apparatus. 13... Reaction chamber, 20... First gas supply port, 22... Semiconductor wafer, 23...
...Susceptor, 25...Partition plate, 28...
...Second gas supply port, 3Q... ...Infrared lamp, 32...Partition rod, 33.
...Multilayer plate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
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Claims (2)

[Claims] (1) A reaction chamber having a gas supply port at one end and a gas discharge port at the other end, an infrared transmitting section provided in the upper part of the reaction chamber, and a semiconductor wafer provided inside the reaction chamber. In the vapor phase growth apparatus, the reaction chamber includes a susceptor that supports the susceptor, and an infrared lamp provided above the infrared transmitting section, in which the reaction chamber includes a lower chamber having the gas supply port, the gas discharge port, and the susceptor; A first reaction in which an infrared-transparent partition member is provided to partition the reaction chamber into an upper chamber, an appropriate number of communication ports are formed in the partition, and a gas supply port on the lower chamber side of the reaction chamber is thermally decomposed to form a solid phase. Serves as a gas and carrier gas supply port, forms a solid phase in the upper chamber of the reaction chamber by reaction with the first reaction gas, and does not itself form a solid phase by thermal decomposition or is difficult to thermally decompose. A vapor phase growth apparatus characterized in that a supply port for a second reaction gas and an inert gas is formed. (2) The vapor phase growth apparatus according to claim 1, wherein the first reactive gas is monosilane gas, the carrier gas is helium, the second reactive gas is oxygen, and the inert gas is nitrogen. .