JPH06151317A - Cvd equipment - Google Patents

Abstract

PURPOSE:To improve uniformity of dope agent concentration, by reducing activation energy diffenence by preliminarily heating the dope agent, and making the distance from a dope agent feeding port to each semiconductor wafer equal. CONSTITUTION:This equipment is a low pressure CVD equipment for forming a poly silicon film on a semiconductor wafer. A dope agent preheating chamber 16 which heats dope agent at a specified temperature is installed in an inner tube 15 of a reaction chamber 11 which tube is formed of cylindrical quartz and isolated from the open air. The introduced dope agent 17 is heated at a specified temperature through the dope agent preheating chamber 16. A plurality of apertures 19 are formed in the dope agent preheating chamber 16, and the dope agent 17 is supplied in a shower type from the peripheral part of a semiconductor wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CVD apparatus in a semiconductor manufacturing facility, and in particular, it is applied to a CVD apparatus capable of providing a uniform dopant concentration in a CVD film in supplying a dopant to a semiconductor wafer. Regarding effective technology.

[0002]

2. Description of the Related Art For example, in a low pressure CVD apparatus in a semiconductor manufacturing facility, while a process gas is supplied into a reaction chamber, it is sucked by a vacuum pump to depressurize the reaction chamber to a pressure lower than atmospheric pressure (0.1 to 1. CV while 0 Torr)
It is used to form a D film and is mainly used to form a polysilicon film and a silicon nitride film.

In this CVD apparatus, in a reaction chamber which is shielded from the outside air, for example, in a cylindrical inner tube 1 as shown in FIG. 4, a dopant 2 made of elements constituting a thin film material and a process gas 3 are the same. In the method, that is, the semiconductor wafer is supplied into the reaction chamber in the gas exhaust direction from the inlet / outlet port.

[0004]

However, in the prior art as described above, the case where the activation energy of the dopant is significantly different from the activation energy of the process gas is not taken into consideration, and this energy difference causes the CVD film to have a different energy. Is a problem in the generation of.

That is, the energy difference between the dopant and the process gas greatly affects the concentration of the dopant in the film, and when the energy difference is large, the concentration of the dopant changes depending on the position in the reaction chamber. There is a problem that uniformity cannot be obtained.

Further, since the distances from the supply port of the doping agent to the respective semiconductor wafers are different, the concentration of the doping agent in the film varies depending on the position in the reaction chamber, so that the semiconductor wafers to be batch-processed have different concentrations. There is a problem that a CVD film having a uniform dopant concentration cannot be formed.

Therefore, an object of the present invention is to reduce the activation energy difference by preheating the doping agent, and to keep the distance from the supply port of the doping agent to each semiconductor wafer at an equal distance so that the doping agent concentration is uniform. It is to provide a CVD apparatus capable of improving the property.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0009]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the CVD apparatus of the present invention supplies a predetermined dopant and process gas consisting of the elements constituting the thin film material onto a semiconductor wafer in a reaction chamber which is shielded from the outside air, so that the gas phase or the surface of the semiconductor wafer is exposed. Is a CVD apparatus for forming a desired thin film by the chemical reaction, and has a doping agent preheating chamber for heating the doping agent to a predetermined temperature in the inner tube of the reaction chamber.

In this case, when the doping agent is supplied through the doping agent preheating chamber, it is supplied in a shower type from the peripheral portion of the semiconductor wafer.

The dope preheating chamber is divided into a plurality of parts, and the flow rate of the dope is controlled in each of the divided dope preheating chambers.

[0013]

According to the above-described CVD apparatus, since the doping agent preheating chamber is provided in the inner tube, the difference in activation energy from the process gas can be reduced. That is, since the doping agent is heated before flowing into the reaction chamber, the doping agent reacts promptly after flowing into the reaction chamber and is taken into the film.

In this case, the dopant is supplied in a shower type from the peripheral portion of the semiconductor wafer to keep the distance from the supply port of the dopant to each semiconductor wafer equal,
It is possible to reduce the variation in the concentration of the dopant in the film depending on the position in the reaction chamber. That is, the doping agent is uniformly fed into the reaction chamber, and the doping agent is uniformly spread in the reaction chamber, so that the film of each semiconductor wafer is uniformly doped.

Further, by controlling the flow rate of the dopant in each of the plurality of divided preheating chambers for the dopant,
By controlling the concentration of the doping agent, it is possible to further improve the uniformity of the concentration of the doping agent.

This makes it possible to form a CVD film having a uniform dopant concentration on each of the semiconductor wafers in the batch processing in the reaction chamber.

[0017]

Embodiment 1 FIG. 1 is a schematic diagram showing a CVD apparatus which is an embodiment of the present invention, and FIG. 2 is a schematic construction diagram showing a reaction chamber used in the CVD apparatus of this embodiment.

First, the structure of the CVD apparatus of this embodiment will be described with reference to FIG.

The CVD apparatus of this embodiment is, for example, a low-pressure CVD apparatus for forming a polysilicon film on a semiconductor wafer, and has a reaction chamber 11 made of cylindrical quartz or the like which is shielded from the outside air, and a reaction chamber 11 inside the reaction chamber 11. A gas supply control unit 12 that controls the supply of a predetermined dopant and process gas composed of the elements that make up the thin film material, and a wafer heating unit 1 that heats the semiconductor wafer in the reaction chamber 11 by a resistance heater or the like.
3 and a vacuum exhaust unit 14 for decompressing the inside of the reaction chamber 11 with a mechanical booster pump or the like.

Further, the inner tube 15 of the reaction chamber 11
As shown in FIG. 2, a dope preheating chamber 16 for heating the dope to a predetermined temperature is provided therein, and the dope 17 introduced from the supply port is brought to a predetermined temperature through the dope preheating chamber 16. It is heated so that the difference in activation energy from the process gas 18 is reduced.

Further, a plurality of openings 19 are formed in the doping agent preheating chamber 16, and when the doping agent 17 is supplied through these openings 19, a semiconductor wafer (not shown) is passed through the doping agent preheating chamber 16. The structure is such that it is supplied from the peripheral part in a shower type.

The dope preheating chamber 16 in the inner tube 15 can be easily manufactured by inserting a cylindrical quartz tube having a shower-like hole into the inner tube 15 and welding both ends.

Next, the operation of this embodiment will be described.

The CVD apparatus configured as described above supplies the process gas 18 into the reaction chamber 11 and sucks the process gas 18 from one of the process gas 18 to reduce the pressure in the reaction chamber 11 to a pressure lower than the atmospheric pressure (0.1 to 0.1). The CVD film is formed while the pressure is 1.0 Torr.

For example, in forming a polysilicon film, monosilane gas (Si
H ₄ ) is used, and phosphorus (P) is supplied as the dopant 17. Then, due to the generation temperature of about 600 ° C., a polysilicon film (P-do
ped-poly Si film) is generated.

In this case, the doping agent 17 is introduced into the doping agent preheating chamber 16 and heated in the doping agent preheating chamber 16 to a temperature at which the activation energy is almost equal to that of the process gas 18.

Then, the dope 17 is uniformly supplied into the reaction chamber 11 by supplying the dope 17 to the reaction chamber 11 through the plurality of openings 19 of the dope preheating chamber 16 in a shower type, and the dope 17 is uniformly spread in the reaction chamber 11. Further, it is possible to react more rapidly and be taken into the film, and to dope the plurality of semiconductor wafers (not shown) by the batch processing uniformly with the doping agent 17.

Therefore, according to the CVD apparatus of this embodiment,
By providing the doping agent preheating chamber 16 in the inner tube 15 of the reaction chamber 11, the difference in activation energy between the doping gas 17 and the process gas 18, which has been a problem in the related art, can be reduced, and the doping agent 17 can be quickly discharged. It is possible to make the doping agent concentration uniform for a plurality of semiconductor wafers because it can be incorporated into the film by reacting with.

Furthermore, by forming a plurality of openings 19 in the dopant preheating chamber 16, the dopant 17 can be supplied in a shower type from the peripheral portion of the semiconductor wafer, whereby the reaction chamber 11 is formed. It is possible to reduce the variation in the concentration of the dopant 17 in the film due to the internal position.

[0030]

[Embodiment 2] FIG. 3 is a schematic configuration diagram showing a reaction chamber used in a CVD apparatus according to another embodiment of the present invention.

The CVD apparatus of this embodiment is similar to the first embodiment in that the low pressure CV for forming a polysilicon film on a semiconductor wafer is used.
D device, as shown in FIG. 3, a plurality of openings 19 are formed in the inner tube 15 of the reaction chamber 11, and the dope agent preheating chamber 16 for heating the dope agent 17 to a predetermined temperature is provided.
The difference from the first embodiment is that the structure of the doping agent preheating chamber 16a is different.

That is, the dope preheating chamber 16a of this embodiment is divided into a plurality of independently controllable chambers,
A mass flow controller (MFC) 20 is connected to each of the divided dope preheating chambers 16a,
With this mass flow controller 20, the doping agent 17
The flow rate is controlled.

Therefore, according to the CVD apparatus of this embodiment,
Since the mass flow controller 20 is connected to each of the divided preheating chambers 16a, the flow rate of the doping agent 17 can be controlled in each preheating chamber 16a. The uniformity of the dopant concentration can be further improved.

Although the invention made by the present inventor has been specifically described based on the first and second embodiments, the present invention is not limited to the above embodiments and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

For example, in the CVD apparatus of this embodiment, a low pressure C for forming a polysilicon film on a semiconductor wafer is used.
Although the case of the VD device has been described, the present invention is not limited to the above-mentioned embodiment, and a silicon oxide film (S
It is also widely applicable to a CVD apparatus for forming other CVD films such as iO ₂ ), silicon nitride film (Si ₃ N ₄ ) and PSG film.

Further, it is needless to say that the present invention is not limited to the low pressure CVD apparatus, but can be applied to other CVD apparatuses for doping impurities such as a normal pressure CVD apparatus and a plasma CVD apparatus.

[0037]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1) To reduce the difference in activation energy between the doping agent and the process gas by having a doping agent preheating chamber for heating the doping agent to a predetermined temperature in the inner tube of the reaction chamber. As a result, the dopant can be made to flow into the reaction chamber and then rapidly reacted to be taken into the film, so that the dopant concentration can be made uniform for a plurality of semiconductor wafers.

(2) When the doping agent is supplied through the preheating chamber, the distance from the supply port of the doping agent to each semiconductor wafer can be increased by supplying the doping agent from the peripheral portion of the semiconductor wafer to the shower type. Since the semiconductor wafers can be kept uniform and uniformly doped into each semiconductor wafer, it is possible to reduce variations in the concentration of the dopant in the film depending on the position in the reaction chamber.

(3). The dope preheating chamber is divided into a plurality of
By controlling the flow rate of the doping agent in each of these divided preheating chambers for the doping agent, the concentration of the doping agent can be controlled with high accuracy, and thus the uniformity of the doping agent concentration is further improved. It becomes possible.

(4) According to the above (1) to (3), even if the difference in activation energy between the dopant and the process gas is large among a plurality of semiconductor wafers in the batch processing in the reaction chamber, each semiconductor wafer Therefore, it is possible to obtain a CVD apparatus capable of forming a CVD film having a uniform dopant concentration.

(5) Since the uniformity of the dopant concentration in the CVD film can be improved by the above (1) to (3),
It is possible to obtain a CVD apparatus capable of improving the processing capacity due to the uniformity of the doping agent.

(6) By the above (1) to (3), it is possible to obtain a CVD apparatus which can eliminate the dopant diffusion step in the semiconductor integrated circuit device manufacturing process.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a CVD apparatus that is Embodiment 1 of the present invention.

2 is a schematic configuration diagram showing a reaction chamber used in the CVD apparatus of Example 1. FIG.

FIG. 3 is a schematic configuration diagram showing a reaction chamber used in a CVD apparatus that is Embodiment 2 of the present invention.

FIG. 4 is a schematic configuration diagram showing a reaction chamber used in a CVD apparatus which is an example of a conventional technique.

[Explanation of symbols]

 1 Inner Tube 2 Doping Agent 3 Process Gas 11 Reaction Chamber 12 Gas Supply Control Section 13 Wafer Heating Section 14 Vacuum Evacuation Section 15 Inner Tube 16, 16a Doping Agent Preheating Chamber 17 Doping Agent 18 Process Gas 19 Opening 20 Mass Flow Controller

Claims (3)

[Claims] 1. A predetermined dopant and process gas consisting of elements constituting a thin film material are supplied onto a semiconductor wafer in a reaction chamber which is shielded from the outside air, and a desired reaction is performed by a chemical reaction in a gas phase or on the surface of the semiconductor wafer. CV forming thin film
D device in the inner tube of the reaction chamber,
A CVD apparatus having a doping agent preheating chamber for heating the doping agent to a predetermined temperature. 2. The CVD apparatus according to claim 1, wherein when the doping agent is supplied through the doping agent preheating chamber, it is supplied in a shower type from the peripheral portion of the semiconductor wafer. 3. The CVD according to claim 1, wherein the doping agent preheating chamber is divided into a plurality of parts, and the flow rate of the doping agent is controlled in each of the divided doping agent preheating chambers. apparatus.