JP3077583B2 - Semiconductor device manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device using a liquefied gas having a low boiling point and having a gas pipe for supplying the liquefied gas from a gas source to a processing chamber. The present invention relates to a semiconductor device manufacturing apparatus.

[0002]

2. Description of the Related Art In a conventional semiconductor device manufacturing apparatus of this type, a gas liquefied in a liquefied gas source may be cooled and liquefied again while flowing through a gas pipe to a processing chamber. Effective gas may not be obtained in the processing chamber. As a technique for solving such a problem, there is a technique proposed in, for example, Japanese Utility Model Laid-Open No. 4-110754. In this technique, as shown in FIG. 5, a part of a gas pipe 3 for flowing gas from a gas cylinder 2 to a reaction chamber 1, here, a gas having first and second valves 4 and 5 and a mass flow controller 8. An electric heater 11 is provided in a part of the pipe 3, and the electric heater 11 is controlled by a temperature control circuit 12 to heat the gas pipe 3 and prevent a temperature of a gas flowing through the gas pipe 3 from lowering. Prevents re-liquefaction of gas.

However, in this prior art, since only a part of the length of the gas pipe in the longitudinal direction is heated by the electric heater 11, when the temperature of the outside air is low, the temperature other than the heated part becomes the liquefied gas. In some cases, the temperature is lowered to a temperature, and as a result, a problem that the gas is reliquefied tends to occur. When the gas is reliquefied in the gas pipe, the gas flow rate fluctuates, the manufacturing process becomes unstable, and the product yield decreases. Further, it takes several hours to return the reliquefied gas pipe to a normal state again, which affects productivity, and particularly affects corrosive gases (Cl ₂ , BCl).
_The reliquefaction of ₃ ) accelerates the corrosion of the inner wall of the gas pipe and affects the reliability.

In order to solve such a problem, FIG.
The techniques shown in the following are conceivable. In this technique, the first valve 4
An electric heater 11C is provided in a long area of the gas pipe 3 extending from the first valve to the second valve 5, and by heating the gas pipe 3 in this area, the temperature of the gas pipe 3 is prevented from being partially lowered. I have. In this way, since the long region of the gas pipe 3 can be heated by the electric heater 11C, a temperature drop in this region can be prevented, and re-liquefaction of gas can be prevented.

[0005]

According to the study of the present inventor, re-liquefaction of gas in a gas pipe is not sufficient if the temperature is simply maintained at a predetermined level or more. It has been found that unevenness is a major factor. That is, the reliquefaction of gas in the gas pipe is most affected by pressure and temperature. In the case of the same volume, the higher the pressure, the lower the state energy proceeds, so that re-liquefaction becomes easier. Although reliquefaction due to temperature also occurs below the boiling point, the reliquefaction phenomenon in the gas piping occurs even above the boiling point, so it is strongly affected by not only the temperature but also the pressure. If the inside of the pipe is under reduced pressure, reliquefaction at room temperature does not occur, and there is no problem. When the inside of the pipe is under pressure, reliquefaction occurs due to temperature unevenness. When the temperature on the gas cylinder (upstream) side is high, a large amount of liquefied gas is vaporized and flows into the gas pipe. However, if there is a part of the pipe that is locally cooled under the influence of outside air, the amount of gas that can be vaporized at that temperature decreases and exceeds the saturated vapor pressure. It will be liquefied.

Therefore, ideally, it is desirable that the temperature unevenness does not occur over the entire length of the gas pipe. In this regard, in the technique shown in FIG. 6, the long area of the gas pipe is heated by the electric heater, which is effective in making the temperature of the long area uniform. However, in practice, it is difficult to uniformly wind the electric heater around the gas pipe. Therefore, a portion where the electric heater is not wound is affected by the outside air, and a low-temperature portion is locally generated. Also, since the electric heater gradually deteriorates as you continue to use it,
When viewed in the length direction of the gas pipe, the deterioration of the electric heater becomes temperature unevenness as it is. Thus, it is actually difficult to completely prevent the occurrence of temperature unevenness in the gas piping. Even if the temperature difference is a few degrees, re-liquefaction occurs in a small amount, and the re-liquefaction gradually spreads in the pipes like a snowball, eventually stopping the gas flow.

An object of the present invention is to provide a semiconductor device manufacturing apparatus capable of preventing the re-liquefaction of a gas caused by such temperature unevenness in a gas pipe.

[0008]

Means for Solving the Problems] manufacturing apparatus of the present invention, prior to
The temperature distribution of the gas pipe drops from the downstream side of the gas to the upstream side
A part of the gas pipe connecting the gas cylinder storing the liquefied gas so as to have a continuous temperature gradient in the direction and the reaction chamber for performing the required reaction treatment is covered with a heat insulating material. A heating device is selectively provided in a downstream region of the covered gas pipe. In this case, a mass flow controller for controlling the flow rate of the liquefied gas is provided in a part of the gas pipe, a gas pipe between the gas cylinder and the mass flow controller is covered with the heat insulating material, and a heating device is provided. . In this case, the heating device is provided only on the mass flow controller side of the gas pipe. Thus, the gas pipe is configured as a gas pipe having a temperature gradient in which the heating temperature is high on the downstream side and low on the upstream side.

Further, the manufacturing apparatus of the present invention provides a gas pipe having a high temperature.
Degree distribution is continuous in the downward direction from the downstream side of the gas to the upstream side
A plurality of heating devices capable of covering a partial region of a gas pipe having a pressurized state inside the pipe with a heat insulating material so as to have a temperature gradient, and individually controlling the temperature at a plurality of locations of the gas pipe coated with the heat insulating material. Wherein at least one of the heating devices is located in a downstream region of the gas pipe. In this case, a plurality of temperature sensors are provided along the gas pipe,
It is preferable to perform a plurality of heating devices individually based on the detected temperatures of the temperature sensors.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an example in which the present invention is applied to a low pressure CVD apparatus. The reaction chamber 1 is a gas pipe 3
Is connected to a gas cylinder 2 which is a gas source of SiH ₂ Cl ₂ gas and NH ₃ gas. The gas pipe 3 has the first
Or the fourth valves 4, 5, 6, 7 are interposed and arranged,
The switching of these valves is controlled, and the mass flow controller 8 provided in the gas pipe 3 controls the flow rate of the gas supplied to the reaction chamber 1. The reaction chamber 1 is controlled to a predetermined negative pressure by a vacuum pump 9.
In the gas pipe 3, the first gas close to the gas cylinder 2 is used.
A heat insulator 10 is provided between the valve 4 and the second valve 5 immediately before the mass flow controller 8, and the heat insulator 10 covers the region of the gas pipe 3. In the area of the gas pipe 3 covered with the heat insulating material 10, an electric heater 11 is provided on a part of the downstream side thereof, and the temperature control circuit 1 is provided.
2 is configured to control the heating temperature of the electric heater 11. The electric heater 11 is provided with a temperature sensor 13, and the heating temperature is controlled to a predetermined temperature based on the temperature detected by the temperature sensor 13.

In this configuration, the heating of the electric heater 11 is controlled by the temperature control circuit 12, and the temperature of the portion of the gas pipe 3 is adjusted to 40.degree. The gas pipe 3 is made of a heat insulating material 10.
Since the pipe is not affected by heat radiation due to outside air, wind, or the like, the gas pipe 3 has a temperature gradient that gradually decreases from the second valve 5 to the first valve 4. For this reason, the reaction chamber 1
SiH ₂ Cl ₂ and NH ₃ gas flowing toward
The gas flows through the gas pipe 3 in the heat insulating material 10 from the first valve 4 toward the second valve 5 in a slightly increasing temperature direction. As described above, since the gas flows in the direction in which the temperature increases, the saturated vapor pressure increases in the same pressure, and the gas does not re-liquefy in the gas pipe 3. The flow rate of the gas is controlled to 0.1 SLM for SiH ₂ Cl _{2 and} 0.9 SLM for NH ₃ by the mass flow controller 8.
It is introduced into the reaction chamber 1 at 00 ° C. In the reaction chamber 1, residual gas not involved in the growth of the nitride film is exhausted by the vacuum pump 9.

As described above, the gas pipe 3 is covered with the heat insulating material 10, and the temperature distribution of the gas pipe 3 is formed such that a temperature gradient in a downward direction from the downstream side of the gas to the upstream side of the gas is formed. FIG. 2 is a diagram showing this temperature gradient. In the figure, the solid line shows the temperature gradient obtained by the present invention, and the broken line shows the temperature distribution in the conventional gas pipe shown in FIG. As can be seen, in the prior art, even if a long area of the gas pipe is heated by an electric heater, it is affected by the outside air, wind and deterioration of the heater. Temperature fluctuations occur in the gas piping that fluctuates in ° C. On the other hand, in the present invention, since the gas pipe 3 is covered with the heat insulating material 10, the temperature unevenness due to the influence of the outside air and the wind hardly occurs. Further, an electric heater 11 is provided on the downstream side of the gas pipe 3, and a temperature gradient is formed in the gas pipe 3 such that the temperature is gradually increased from the upstream side to the downstream side.

For example, in the case of the present embodiment, an electric heater of 200 W is used, a heat insulating material made of glass wool having a thickness of 30 mm is used, a SUS316L, 1/4 inch gas pipe is used, and the electric heater is set at 40 ° C. In this case, the temperature of the pipe 20 m upstream is 39 ° C., which is a linearly decreasing temperature gradient. For this reason, even if temperature irregularities occur in the gas piping, the temperature is gradually increased from the upstream side to the downstream side, so that the flowing gas does not locally decrease in temperature. No reliquefaction occurs.

Further, in this embodiment, the gas pipe 3
The upper side of the mass flow controller 8 is in a pressurized state, and the downstream side is in a depressurized state. As described above, since the reliquefaction of the gas is likely to occur in a pressurized state where the gas amount per deposition is large, the heat insulating material 10 and the electric heater 11 are connected to the gas pipe upstream of the mass flow controller 8 in the pressurized state. By providing and forming a temperature gradient here, it is possible to effectively prevent the above-mentioned reliquefaction.

Therefore, reliquefaction of the gas is prevented, whereby the production process is stabilized, the product yield is stabilized, and the productivity and the reliability of the piping are improved. Further, since it is not necessary to return the reliquefied gas pipe to a normal state again, a several-hour process for gasification of gas, which has been conventionally required, is not required, and a decrease in productivity is suppressed.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a configuration diagram of a main part of the second embodiment of the present invention, and portions equivalent to those of the first embodiment are denoted by the same reference numerals. In this embodiment, is effective when the pipe length of the gas pipe 3 is 100 m, 200 meters and a long, covers the gas pipe 3 with a heat insulating material 10, most downstream position of the heat insulating material-covered gas pipe A first electric heater 11A, and a second electric heater 1 at a substantially intermediate position in the longitudinal direction of the gas pipe 3 covered with the heat insulating material 10.
1B is provided. Moreover, each electric heater 11A, 11
Temperature sensors 13A and 13B are provided in the vicinity of B, respectively, and detect the temperature of that portion of the gas pipe heated by each electric heater. Each of the electric heaters 11A, 1A
1B is configured to be individually temperature-controlled by the temperature control circuit 12 based on the detected temperatures of the temperature sensors 13A and 13B, respectively.

In this configuration, the temperature of the first electric heater 11A is adjusted to 40 ° C. by the temperature control circuit 12. With only the first electric heater 11A, the temperature on the upstream side of the gas pipe 3 near the gas cylinder 2 is reduced by about 3 ° C., so that a sufficient temperature gradient can be obtained. There is a possibility that the influence of disturbance cannot be sufficiently suppressed. Therefore, the second electric heater 11B is attached, and the intermediate region of the gas pipe 3 is heated to correct the temperature so that the temperature does not drop too much. In this case, the second electric heater 11B is 10% of the gas pipe length from an intermediate position in the length direction of the gas pipe.
By installing it on the downstream side, the temperature near the middle of the gas pipe length is adjusted. Further, in this case, it is preferable to control so that the temperature of the portion heated by the second electric heater 11B does not become extremely higher than that of a region downstream therefrom.

As a result, as shown in FIG. 4, in the first embodiment, a decrease in the temperature near the first valve 4 which has decreased by 3 ° C. is suppressed to about 1.5 ° C. Maintain a temperature gradient in the gas piping. Even if the electric heater deteriorates, the continuous area of the gas pipe is not heated by the electric heater, so that the fluctuation width of the pipe temperature can be reduced. As described above, since a temperature gradient with almost no temperature unevenness is generated in the gas pipe, reliquefaction can be suppressed, thereby stabilizing the manufacturing process, stabilizing the manufacturing yield, and improving the productivity.

[0019]

As described above, the present invention provides a gas pipe
Temperature distribution in the downward direction from the gas downstream to the upstream
A part of the gas pipe for supplying the liquefied gas to the reaction chamber with a temperature gradient is covered with a heat insulating material, and a heating device is selectively provided in a downstream area of the gas pipe covered with the heat insulating material. Therefore, it is possible to suppress the occurrence of temperature unevenness due to the external influence of the gas pipe by the heat insulating material,
Since the heating device forms a temperature gradient in which the temperature is gradually increased from the upstream side to the downstream side, it is possible to prevent gas re-liquefaction caused by temperature unevenness, and thereby, the semiconductor to be manufactured. The effect that the product yield of an apparatus improves and productivity and reliability can be improved is obtained. In addition, a plurality of heating devices capable of individually controlling the temperature are provided at a plurality of locations of the gas pipe covered with the heat insulating material, while covering a partial region of the gas pipe in which the inside of the pipe is in a pressurized state. By providing at least one of them in the downstream region of the gas pipe, the temperature gradient in the pipe in a pressurized state can be arbitrarily set, and reliquefaction can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a temperature gradient in a gas pipe according to the first embodiment.

FIG. 3 is a configuration diagram of a main part of a second embodiment of the present invention.

FIG. 4 is a diagram showing a temperature gradient in a gas pipe according to a second embodiment.

FIG. 5 is a partial configuration diagram showing an example of a conventional configuration.

FIG. 6 is a partial configuration diagram showing another example of the conventional configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Gas cylinder 3 Gas piping 4-7 Valve 8 Mass flow controller 9 Vacuum pump 10 Heat insulating material 11, 11A, 11B Electric heater 12 Temperature control circuit 13, 13A, 13B Temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/31 H01L 21/205 C23C 16/00 C30B 25/00

Claims (6)

(57) [Claims] 1. A gas cylinder storing a liquefied gas and a reaction chamber for performing a required reaction process are connected by a gas pipe.
In a semiconductor device manufacturing apparatus comprising a gas supply system for gasifying the liquefied gas and supplying the gas to the reaction chamber, the gas
The temperature distribution of the pipe is in the downward direction from the gas downstream to the upstream.
Manufacturing a semiconductor device , wherein a part of the gas pipe is covered with a heat insulating material so as to have a continuous temperature gradient, and a heating device is provided in a downstream area of the gas pipe coated with the heat insulating material. apparatus. 2. A mass flow controller for controlling a flow rate of the liquefied gas is provided in a part of the gas pipe, a gas pipe between the gas cylinder and the mass flow controller is covered with the heat insulating material, and 2. The apparatus for manufacturing a semiconductor device according to claim 1, further comprising a heating device. 3. The semiconductor device manufacturing apparatus according to claim 2, wherein said heating device is provided only on a side of said mass flow controller of said gas pipe. 4. The gas pipe covered with the heat insulating material.
2. The semiconductor device manufacturing apparatus according to claim 1 , wherein said gas is in a pressurized state . 5. A gas cylinder in which a liquefied gas is stored and a reaction chamber for performing a required reaction process are connected by a gas pipe whose inside is in a pressurized state, and the liquefied gas is gasified and supplied to the reaction chamber. It provided for supplying gas supply system, the temperature of the gas pipe
Degree distribution is continuous in the downward direction from the downstream side of the gas to the upstream side
A plurality of heating devices capable of individually controlling the temperature are provided at a plurality of locations on the gas pipe covered with the heat insulating material, while covering a partial area of the gas pipe so as to have a temperature gradient. Wherein at least one of the above is located in a downstream region of the gas pipe. 6. The semiconductor device manufacturing apparatus according to claim 5, wherein a plurality of temperature sensors are provided along the gas pipe, and the plurality of heating devices are individually performed based on the detected temperatures of the respective temperature sensors.