JPH11186171A - Semiconductor manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing device which does not worsen the particle level in a reaction chamber due to the reverse flow of a ballast gas into the reaction chamber through the part of an exhaust pipe coated with resulted products of reaction adhering to the part while the device adopts a gas ballast method for controlling the pressure in the reaction chamber. SOLUTION: A semiconductor manufacturing device is provided with a reaction chamber 1 in which films are respectively formed on substrates 15, an evacuating means which evacuates the gas in the reaction chamber 1, an evacuating piping 3 which connects the chamber 1 to the evacuating means, and a gas injector 11 which supplies a gaseous starting material to the chamber 1. The device adopts a gas ballast method for controlling the pressure in the chamber 1 and an introducing section, through which a ballast gas is introduced to the chamber 1 for controlling the pressure, is provided in the chamber 1 which is positioned on the upstream side of the piping 3 in flowing direction of the gaseous starting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus for controlling the pressure of a film forming reaction chamber, and more particularly, to controlling the pressure of the film forming reaction chamber by adjusting the flow rate of all gases flowing into a vacuum exhaust device. The present invention relates to a semiconductor manufacturing apparatus that performs control.

[0002]

2. Description of the Related Art As an example of the prior art, a low pressure CVD (Chemical Vapor Deposition) apparatus as a semiconductor manufacturing apparatus will be described. Low pressure CVD equipment
With the recent increase in diameter of wafers, they have been widely used because their throughput and uniformity can be ensured. Particularly recently, polycrystalline silicon and Si
Most 3N4 films are manufactured in this manner. Decompression C
It is known that VD has a slightly lower deposition rate than normal pressure, but has excellent uniformity within the wafer surface and between wafers, and exhibits excellent coverage even with uneven steps on the surface. I have.

In general, a low pressure CVD apparatus includes a reaction chamber for forming a film on a substrate, a gas supply system for supplying a raw material gas and the like into the reaction chamber, and a vacuum exhaust device for exhausting the gas in the reaction chamber. And an exhaust pipe connecting the reaction chamber and the vacuum exhaust device.

FIG. 5 shows a general batch type vertical reduced pressure CVD.
1 shows a schematic configuration of an apparatus. In FIG.
1 is a reaction chamber for causing a film formation reaction on a substrate, 2 is a gas supply system for supplying a source gas for film formation, 3 is an exhaust pipe, 4 is a pressure control device for introducing ballast gas, and 5 is a reaction chamber in the reaction chamber. A vacuum exhaust device for exhausting gas, a pressure gauge 6 for measuring the pressure in the reaction chamber 1, and a valve 7 are provided.

By the way, in principle, the larger the total gas flow rate flowing into the vacuum exhaust device, the higher the pressure in the reaction chamber,
Therefore, the degree of vacuum deteriorates. There is a method of controlling the pressure in the reaction chamber by utilizing this characteristic. It is a method of introducing an inert gas such as N2 into the exhaust pipe by adjusting the flow rate thereof in order to maintain a desired degree of vacuum in the reaction chamber.

In general, such a pressure control method is called a gas ballast method, and the inert gas used here is called a ballast gas. The outline of the pressure control method using the gas ballast method will be described below. Flow control device (pressure control device 4) for ballast gas piping in gas ballast system
Which operates in conjunction with a pressure gauge 6 for measuring the pressure in the reaction chamber 1.

In such a configuration, when the pressure in the reaction chamber 1 is lower than a desired set value, the flow rate of the ballast gas is increased to increase the total flow rate of the gas flowing into the vacuum evacuation device 5 to increase the reaction rate. The pressure in the chamber 1 can be increased.
On the other hand, when the pressure in the reaction chamber 1 is higher than the set value, the operation opposite to the above control is performed. As described above, the gas ballast system controls the pressure in the reaction chamber 1 by adjusting the flow rate of the ballast gas.

[0008] However, a reaction product due to a source gas that has not contributed to film formation adheres to a wall surface inside the exhaust pipe 3 in the low-pressure CVD apparatus. Especially Si ₃ N ₄ CVD or T
In EOS SiO ₂ CVD, the amount of reaction products deposited in the exhaust pipe 3 tends to be large.

FIG. 6 schematically shows the internal structure of the reaction chamber 1 and the positions where reaction products are generated. In FIG. 6, 1 is a reaction chamber,
3 is an exhaust pipe, 11 is a gas injector for introducing a source gas into the reaction chamber 1, 12 is an outer tube, 13 is an inner tube, 14 is a transport boat for transporting the substrate 15, 15 is a substrate, and 16 is an exhaust pipe 3. It is a reaction product attached to.

A source gas is introduced into the reaction chamber 1 by a gas injector 11 provided at a lower portion inside the inner tube 13. Thereafter, the raw material gas is thermally decomposed, reacts on the surface of the substrate 15 in the transport boat 14 while rising and diffusing, and a film is formed on the substrate 15. Thereafter, the gas supplied from the gas supply system 2 while remaining the unreacted raw material gas passes through the space between the inner tube 13 and the outer tube 12 disposed outside the inner tube 13 and is exhausted from the exhaust pipe 3. At this time, the reaction product 16 adheres to the exhaust pipe 3.

In such a gas ballast type pressure control method, the ballast gas flows back to the reaction chamber 1 through the exhaust pipe 3, and the reactant 16 attached to the exhaust pipe 3 is moved into the reaction chamber 1. The phenomenon of pushing back may occur. For example, when the source gas is supplied from the gas supply system 2 into the reaction chamber 1 and the pressure control in the reaction chamber 1 is started at the same time, or when the set pressure in the reaction chamber 1 is supplied to the total gas flow rate. If the flow rate is too high, and furthermore, at an initial stage until the supply gas flow rate and the pressure in the reaction chamber 1 are in an equilibrium state, the ballast gas introduced into the exhaust pipe 3 flows back to the reaction chamber 1 side, and 1 will be controlled.

Therefore, in such a case, when a phenomenon occurs in which the ballast gas flows back into the reaction chamber 1, the reaction products 16 attached to the inner wall of the exhaust pipe 3 are transferred into the reaction chamber 1. It is swept away, and as a result, the particle level in the reaction chamber 1 is deteriorated.

[0013]

As described above, in the conventional semiconductor manufacturing apparatus, the ballast gas introduced for the purpose of controlling the pressure in the reaction chamber removes the portion of the exhaust pipe to which the reaction product adheres. The phenomenon of flowing back into the reaction chamber through the reaction chamber causes a problem that the particle level in the reaction chamber is deteriorated and the reliability and yield of the semiconductor element are deteriorated.

The present invention has been made in view of the above-mentioned problems, and a ballast gas is applied to a portion of an exhaust pipe to which a reaction product adheres while employing a gas ballast method as a pressure control method. It is an object of the present invention to realize a semiconductor manufacturing apparatus which does not flow backward through the reaction chamber and deteriorate the particle level in the reaction chamber.

[0015]

In order to achieve the above object, the present invention provides a reaction chamber for forming a film on a substrate, vacuum evacuation means for evacuating gas in the reaction chamber, In a semiconductor manufacturing apparatus having an exhaust pipe connecting an evacuation unit and a gas supply unit supplying a source gas to the reaction chamber, a gas ballast method is adopted as a pressure control method in the reaction chamber, and the pressure control is performed. A ballast gas introduction unit introduced for the purpose of (1) is installed upstream of the source gas flow from the exhaust pipe.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a pressure control mechanism according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention, in which a batch type vertical CV is used.
3 shows a mechanism inside a reaction chamber in the D apparatus. In FIG. 1, 1 is a reaction chamber, 3 is an exhaust pipe, 4 is a pressure controller, 11
Is a gas injector, 12 is an outer tube, 13 is an inner tube, and 15 is a substrate. The names and numbers of respective parts are the same as those in FIG. 6 for convenience.

This embodiment is different from the prior art in that ballast gas is not introduced into the exhaust pipe 3,
That is, it is introduced directly into the reaction chamber 1. With such a configuration, the ballast gas cannot flow back to the reaction chamber 1 through the exhaust pipe 3, and therefore, the reaction products attached to the inner wall of the exhaust pipe 3 are not removed by the ballast gas. There is no one to be swept away. That is,
The structure of the present embodiment has a structure capable of preventing deterioration of the particle level in the reaction chamber 1 due to a reaction product attached to the inner wall of the exhaust pipe 3.

FIG. 2 shows the configuration of the second embodiment of the present invention. In FIG. 2, 1 is a reaction chamber, 3 is an exhaust pipe, 4 is a pressure control device, 11 is a gas injector, 12 is an outer tube, 13 is an inner tube, and 15 is a substrate. The same thing as FIG. 6 was used. The feature of this embodiment is that the ballast gas introduction portion is provided between the inner tube 13 and the outer tube 12 and near the exhaust port of the reaction chamber 1.

As described above, the introduction of the ballast gas is
By arranging the material gas downstream of the material gas flow (on the side of the vacuum exhaust device), dilution of the material gas by the ballast gas is prevented. If the raw material gas is diluted by the ballast gas, the film formation rate is reduced and the productivity is deteriorated, and also the reaction mode is affected, so that the film quality formed on the substrate 15 is reduced. It is also conceivable that it changes depending on the device structure. By doing so, compared to the ballast gas introduction structure of the first embodiment, the factors affecting the film formation can be reduced as much as possible, and the reproducibility of the film formation for each operation can be improved. Therefore, by implementing the present embodiment, it is possible to prevent the particle level in the reaction chamber 1 from deteriorating, and to maintain the same film quality as before without deteriorating the productivity.

FIG. 3 shows the configuration of the third embodiment of the present invention. In FIG. 3, 1 is a reaction chamber, 3 is an exhaust pipe, 4 is a pressure control device, 11 is a gas injector, 12
Is an outer tube, 13 is an inner tube, and 15 is a substrate, and the names and numbers of respective parts are the same as those in FIGS. 1, 2 and 6. The feature of the present embodiment is that the flow direction of the ballast gas and the flow direction of the raw material gas match.

In general, low pressure CVD is superior in uniformity of film formation because the diffusion of the molecules of the source gas is larger than in normal pressure CVD. However, when the flow directions of the ballast gas and the raw material gas are synchronized, the flow lines of the ballast gas and the raw material gas may interfere with each other, and the flow of the raw material gas may be disturbed. By carrying out the present embodiment, such disturbance of the source gas flow is less likely to occur, and uniformity of the film thickness can be maintained.
The reproducibility of each operation can also be improved.

In the embodiment of the present invention described above, a gas injector is employed as a mechanism for introducing a ballast gas into the reaction chamber, but the present invention is not necessarily limited to this method. As an example, FIG. 4 shows a fourth embodiment of the present invention. This is one in which a ballast gas supply port is provided in a flange portion.

In FIG. 4, 1 is a reaction chamber, 3 is an exhaust pipe,
4 is a pressure control device, 12 is an outer tube, 13 is an inner tube, 15 is a board | substrate, and 16 is a ballast gas supply port provided in the flange part. The same parts as those in FIGS. 1, 2, 3 and 6 are used as the names and numbers of the respective parts. In this embodiment, since the ballast gas supply port is directly provided in the flange portion of the outer tube 12, it is not necessary to particularly provide a piping configuration of the ballast gas injector, and the configuration can be simplified accordingly.

In the present invention, the structure and quantity of the ballast gas introduction section are not limited to the above embodiment. Further, the present invention is not limited to a batch type vertical apparatus, but is also effective for a horizontal apparatus or a single wafer type apparatus. Further, the present invention is not limited to a low pressure CVD apparatus. For example, there is a plasma CVD apparatus or a dry etching apparatus that controls the pressure in the reaction chamber and that can be a source of particles in the exhaust pipe, which deteriorates the particle level of the reaction chamber in which the process is performed. It is also effective for semiconductor manufacturing equipment as long as the ballast method is adopted.

As described above, in an apparatus employing a gas ballast method for controlling the pressure in a reaction chamber in a semiconductor manufacturing apparatus, the ballast gas introduction section, which is the ballast gas introduction mechanism of the present invention, is installed in the reaction chamber. This makes it possible to prevent the reaction product adhering to the inner wall of the exhaust pipe from flowing back into the reaction chamber. Therefore, the particle level in the reaction chamber is not deteriorated, the reliability of the semiconductor element is improved, and the productivity can be improved by improving the yield.

[0026]

As described above, according to the first aspect of the present invention, there is provided a reaction chamber for forming a film on a substrate, a vacuum exhaust means for exhausting gas in the reaction chamber, a reaction chamber and a vacuum exhaust means. And a gas ballast method for controlling the pressure in the reaction chamber in a semiconductor manufacturing apparatus including an exhaust pipe connecting the gas supply means and gas supply means for supplying a source gas to the reaction chamber,
The introduction part of the ballast gas introduced for the purpose of pressure control is arranged upstream of the exhaust gas pipe in the source gas flow. As described above, by introducing the introduction position of the ballast gas introduced for the purpose of controlling the pressure in the reaction chamber upstream of the source gas flow from the portion where the reaction product is attached to the inner wall of the exhaust pipe, Reaction products adhering to the inner wall of the exhaust pipe can be prevented from flowing back into the reaction chamber. Therefore, by adopting such a structure,
It is possible to maintain a good particle level in the reaction chamber and improve the reliability and yield of the semiconductor device.

According to the invention of claim 2 of the present invention, the ballast gas introducing section is provided in the reaction chamber. Thus, the introduction position of the ballast gas is located upstream of the source gas flow from the portion where the reaction product is attached to the inner wall of the exhaust pipe, and does not affect the flow of the source gas during film formation. Can be installed at the site. Therefore, it is possible to maintain a good particle level in the reaction chamber and improve the reliability and yield of the semiconductor element.

Further, in the invention according to claim 3 of the present invention, the ballast gas introduction portion is provided at a position downstream of the substrate gas flow from the substrate and upstream of the exhaust gas flow through the exhaust pipe. Thereby, the introduction position of the ballast gas is set at a position upstream of the source gas flow from the portion where the reaction product is attached to the inner wall of the exhaust pipe, and which does not further affect the flow of the source gas during film formation. Can be installed in further,
Dilution of the source gas can be prevented. Therefore,
It is possible to prevent the productivity from deteriorating due to a decrease in the deposition rate, prevent the quality of the deposited film from changing, maintain a good particle level in the reaction chamber, and improve the reliability and yield of the semiconductor element. Can be improved.

Further, according to the invention of claim 4 of the present invention, the ballast gas introducing portion is formed by introducing the ballast gas in a direction along the flow of the raw material gas flow during the substrate processing in the reaction chamber. Install so as not to disturb the flow. As a result, the introduction of the ballast gas does not affect the flow of the source gas at the time of film formation, the turbulence of the source gas flow does not easily occur, and the uniformity of the film thickness can be maintained. The reproducibility of each repetition is also improved, and the particle level in the reaction chamber is maintained at a good level, so that the reliability and yield of the semiconductor element can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an inside of a reaction chamber in a batch type vertical reduced-pressure CVD apparatus which is an embodiment of a semiconductor manufacturing apparatus of the present invention.

FIG. 2 is a configuration diagram showing an inside of a reaction chamber in a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 3 is a configuration diagram showing an inside of a reaction chamber in a semiconductor manufacturing apparatus according to still another embodiment of the present invention.

FIG. 4 is a configuration diagram showing an inside of a reaction chamber in a semiconductor manufacturing apparatus according to still another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a batch type vertical low pressure CVD apparatus which is an example of a semiconductor manufacturing apparatus.

FIG. 6 is a schematic view of a reaction chamber and an exhaust pipe of a conventional batch type vertical reduced pressure CVD apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reaction chamber, 2 ... Gas supply system, 3 ... Exhaust piping, 4
... pressure control device, 5 ... vacuum evacuation device, 6 ... pressure gauge, 7 ...
Valve, 11 gas injector, 12 outer tube, 13 inner tube, 14 transport boat, 1
5: substrate, 16: reaction product.

Claims (4)

[Claims] A reaction chamber for forming a film on a substrate; a vacuum exhaust means for exhausting gas in the reaction chamber; an exhaust pipe connecting the reaction chamber and the vacuum exhaust means; A gas supply means for supplying a raw material gas, wherein a gas ballast method is adopted as a method of controlling the pressure in the reaction chamber, and an introduction part of a ballast gas introduced for the purpose of pressure control is exhausted. A semiconductor manufacturing apparatus, which is installed upstream of a source gas flow from a pipe. 2. The semiconductor device according to claim 1, wherein the ballast gas introduction unit is provided in the reaction chamber. 3. The semiconductor device according to claim 1, wherein the ballast gas introduction portion is provided at a position downstream of the substrate gas flow from the substrate. 4. The method according to claim 1, wherein the ballast gas introduction section is configured to introduce a ballast gas in a direction along a flow of the source gas flow during substrate processing in the reaction chamber so as not to disturb the flow of the source gas flow. 2. The device according to claim 1, wherein the device is installed.
Alternatively, the semiconductor device according to claim 3.