JPH0725224Y2 - Evaporative gas quantitative extraction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a vaporized gas quantitative extraction device for quantitatively extracting a gaseous raw material such as a semiconductor layer forming material used for manufacturing a semiconductor from a liquid raw material by quantitatively extracting it. It is about.

[Conventional technology]

In a semiconductor manufacturing process, a layer made of an insulating film semiconductor material is formed on the surface of a wafer. Among such materials, there is tetraethyl oxide silane (hereinafter abbreviated as “TEOS”). . This TEOS has a high boiling point of 170 ° C and is difficult to vaporize, and has the property of decomposing at a temperature of about 130 ° C. Generally, a bubbling method or a baking method is used to form an insulating semiconductor layer forming processing chamber. Is being supplied to. Among the above methods, the bubbling method is as shown in FIG. 2, in which TEOS is held in a raw material tank 2 provided inside the heating chamber 1 in a strictly warmed state, TEOS is bubbled in the raw material tank 2 by supplying an inert gas (eg, N ₂ , Ar) whose flow rate is adjusted by a mass flow controller (hereinafter referred to as “MFC”) 3 into the tank 2 as carrier gas. The vaporized gas generated is fed into the processing chamber 5 through the pipe 4. Then, this vaporized gas is sprayed on the surface of the wafer 6 arranged in parallel in the processing chamber 5 to form an insulating semiconductor layer.
The baking method is as shown in FIG. 3, in which the raw material tank 2 is arranged in the heating chamber 1a whose temperature is adjusted, and the MFC 3 is arranged on the downstream side in the heating chamber 1a. With this MFC 3, the flow rate of TEOS sent from the raw material tank 2 is adjusted, and the wafers 6 are sent into the processing chambers 5 arranged side by side. In FIGS. 2 and 3, 7 is an opening / closing valve, 8 is a pressure gauge, and 9 is a variable flow valve.

[Problems to be solved by the invention]

However, in the above bubbling method, since the vaporized TEOS is sent to the processing chamber 5 in a state of being mixed with the inert gas, TE
It is difficult to measure the supply amount of OS, and this concentration becomes thin,
There is a problem that it takes a long time to form the insulating semiconductor layer and the accuracy of the formed layer is deteriorated. In addition, since it is necessary to strictly control the temperature of the heating chamber 1, there is a problem that the operation is difficult. In the baking method, the accuracy of the forming layer is good, and it is not necessary to strictly control the temperature of the heating chamber 1a. However, in order to efficiently vaporize the liquid raw material, it is necessary to increase the vaporizing surface area of the liquid raw material, and accordingly, it is necessary to enlarge the raw material tank 2. Since the raw material tank 2 is disposed in the heating chamber 1a, the heating chamber 1a becomes large.

The present invention has been made in view of such circumstances, and it is possible to miniaturize the heating means while maintaining the advantages of the above-mentioned baking method and to efficiently and stably and quantitatively extract the gas raw material. It is an object of the present invention to provide a vaporized gas quantitative extraction device.

[Means for solving problems]

In order to achieve the above object, the device for extracting a fixed amount of vaporized gas according to the present invention has an inert gas introducing pipe connected to an upper space in a liquid raw material tank via a pressure control valve and a liquid in the liquid raw material tank. A circulation path through which the liquid heating medium circulates by immersing one end side of the liquid raw material extraction pipe in the raw material reservoir and drawing the other end side of the liquid raw material extraction pipe from the liquid raw material tank and connecting it to the lower end of the sealed chamber. Is extended from the outside of the sealed chamber into the sealed chamber, a heating means is provided in the outside portion of the circulation path, and fin portions are formed at a constant interval in the sealed chamber portion, and the vaporized raw material is supplied from the upper end of the sealed chamber. A transfer pipe is extended and its tip is connected to a gas-liquid separator, a gas raw material extraction pipe is extended from the gas outlet of the gas-liquid separator, and a flow rate adjusting means is provided on this pipe, Gas-liquid A configuration that the tip was connected to the liquid material tank to extend the pipe for a liquid raw material feed back from the liquid outlet of the releasing device.

[Action]

That is, the device for extracting a fixed amount of vaporized gas according to the present invention is similar to the conventional example in that a liquid raw material heated and held is bubbled by an inert gas to take out vaporized gas generated at that time, or a raw material tank is heated to a large size. The liquid raw material is not vaporized and taken out by heating it in the chamber, but the liquid raw material taken out by the raw material take-out pipe extending from the raw material tank is vaporized in the sealed chamber heated and held to be taken out to the outside for use. I'm running. Therefore, the sealed chamber can be downsized, and the heating means for heating the system containing it can be downsized significantly. As a result, the large-sized heating chamber as in the conventional example becomes unnecessary. That is, since the portions of the heating circulation passage in the sealed chamber are formed in the fin portions arranged in parallel at regular intervals, the contact area with the liquid raw material is increased, and the heat transfer to the liquid raw material is improved. As a result, the liquid raw material can be effectively vaporized, and the sealed chamber can be downsized. Further, since the carrier gas is not used, there is no problem that the vaporized raw material is diluted. Further, in the device of this invention, since the flow rate adjusting means is provided in the middle of the gas raw material extracting pipe extending from the gas-liquid separator, the finally taken out gas raw material is always kept at an appropriate flow rate. Has the advantage. Further, since the inert gas introduction pipe is connected to the raw material tank via the pressure control valve, the inert gas can be introduced according to the change in the liquid level in the raw material tank, and the inside of the raw material tank is kept constant. Can be kept at pressure. Therefore, the raw material can be constantly and stably supplied, and the evaporation operation can be continuously performed under stable conditions. Further, since the liquid raw material separated in the gas-liquid separator is returned to the liquid raw material tank from the liquid raw material return pipe, the liquid raw material is not wasted and is economical.

Next, this invention will be described in detail based on embodiments.

〔Example〕

FIG. 1 shows an embodiment of this invention. That is, in the figure, 10 is a raw material tank, and the liquid TEOS for forming an insulating semiconductor layer is filled in the lower inner side. A pipe 11 for supplying He gas is connected to the upper end of the raw material tank 10, and the He gas sent from the pipe 11 to the space on the upper side of the raw material tank 10 allows the raw material tank 10 to be supplied.
TEOS inside is maintained in a stable state that is difficult to decompose.
12 is a pressure control valve provided in the pipe 11, and is a raw material tank
When the TEOS in 10 decreases and the pressure of the raw material tank 10 decreases, it automatically opens and He gas is fed into the raw material tank 10. Reference numeral 13 denotes a raw material take-out pipe with a pump 14 extending upward from the bottom side of the raw material tank 10 and penetrating through the ceiling portion to the outside, and its tip is connected to the bottom of a box-shaped sealed chamber 15. A circulation path 16 that circulates between the inside and the outside of the sealed chamber 15 penetrates through the sealed chamber 15, and a portion inside the sealed chamber 15 is formed in a fin portion 17 that is arranged in parallel at a constant interval. A heater 18 is provided on the outside. The circulation path 16 is provided with a circulation pump (not shown) and is filled with a liquid medium inside. The medium is circulated while being heated by the heat generated by the heater 18. However, the inside of the sealed chamber 15 is kept at a temperature of approximately 80 ° C. Therefore, the liquid fed from the raw material tank 10 to the lower side of the sealed chamber 15 through the raw material extraction pipe 13.
TEOS keeps contact with the heated fins 17 and seals the chamber 15
It rises slowly inside, and during that time it is heated and evaporated, and its vaporized gas rises to the upper end side of the sealed chamber 15. Reference numeral 19 denotes a pipe for carrying vaporized gas, which extends from the ceiling of the sealed chamber 15, and has its tip connected to a conventionally known gas-liquid separator 20.
Reference numeral 25 denotes a pipe for taking out a gas raw material, which extends from a gas outlet provided on the upper side of the gas-liquid separator 20.
The gaseous raw material therein is sent to the processing chamber 26.
The processing chamber 26 is equipped with a vacuum pump (not shown),
Due to the action of the vacuum pump, the insides of the pipes 19 and 25 and the gas-liquid separator 20 are made to have a negative pressure, and the vaporized gas in the sealed chamber 15 is supplied to the pipe
9. Suction inside via the gas-liquid separator 20 and the pipe 25.
Reference numeral 27 is an MFC provided between the gas-liquid separator 20 and the processing chamber 26 in the pipe 25, and adjusts the gas raw material passing through the pipe 25 to an appropriate flow rate. Further, 28 is a feed-back pipe extending from a liquid outlet provided at the lower end of the gas-liquid separator 20, and is connected to the upper side of the raw material tank 10 via a tank 30 and an opening / closing valve 29. The pipe 28 is adapted to temporarily store the liquid TEOS separated from the gas in the gas-liquid separator 20 and falling in the tank 30, and send it back to the raw material tank 10 as appropriate. The returned liquid TEOS is mixed with the liquid TEOS in the raw material tank 10 and used again as a raw material.

In this configuration, when the pump 14 and the vacuum pump of the processing chamber 26 are operated, the liquid TEOS in the raw material tank 10 is fed into the sealed chamber 15 via the raw material take-out pipe 13 and is heated by the fin portion 17. Then, it is heated and vaporizes effectively. Then, after being sent to the gas-liquid separator 20 through the pipe 19 in a gas-liquid mixed state, the gas-liquid is separated, and only the gas component is sent to the processing chamber 26 via the pipe 25. As a result, the vaporized gas of TEOS is sprayed on the surface of the wafers arranged in parallel in the processing chamber 26, and an insulating semiconductor layer is formed on the surface. At this time, since the vaporized gas is adjusted to an appropriate flow rate by the MFC 27, the insulating semiconductor layer to be formed is in a good and accurate state.

In this way, the device significantly reduces the size of the sealed chamber 15,
Since the system including the miniaturized sealed chamber 15 is heated, the heating means can be remarkably miniaturized. That is, the downsizing of the sealed chamber 15 is achieved by the sealed chamber.
This is achieved by forming the fin portions 17 in the portion within 15 at regular intervals, thereby increasing the heating area of the liquid TEOS and enabling effective vaporization. Further, the inside of the raw material tank 10 is always kept at a constant pressure, and the liquid raw material is stably supplied, and the gas-liquid separator 20 is gas-liquid separated, and only the gas component is taken out as a raw material to adjust the MFC 27. Therefore, since it is taken out at an appropriate flow rate, it is possible to form an insulating semiconductor layer with good accuracy and goodness. Further, since the raw material tank 10 can be placed outside the heating chamber, TEOS that is unstable at high temperatures can be held in a stable state. Further, since carrier gas is not used, there is no problem such as dilution of TEOS. Furthermore, the liquid TEOS separated by the gas-liquid separator 20 is returned to the raw material tank 10 again for use, which is wasteful.

The liquid raw material is not limited to the above TEOS,
Any liquid raw material that requires vaporization may be used. Further, the pump 14 in FIG. 1 may be removed, and instead of this, the pressure of the He gas supplied from the pressure control valve 12 may be utilized to take out the liquid raw material.

[Effect of device]

As described above, the device for extracting a fixed amount of vaporized gas according to the present invention is provided with a sealed chamber which is heated and held on the downstream side of the raw material tank, and vaporizes the liquid raw material sent from the raw material tank in this sealed chamber to take it out to the outside. I'm running. Therefore, the liquid raw material can be effectively vaporized, and the heating means can be simplified and miniaturized. Further, since the carrier gas is not used, there is no problem that the raw material is diluted. Further, the inside of the raw material tank is always kept at a constant pressure, the liquid raw material is stably supplied, and the gas-liquid separator separates the gas and liquid, and only the gas component is taken out as the raw material, and the flow rate adjusting means is used. Since it is taken out at an appropriate flow rate, it is possible to form an insulating semiconductor layer with good accuracy and goodness. Moreover, the liquid TEOS separated by the gas-liquid separator is returned to the raw material tank and used again, which is wasteful and economical.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams of a conventional example. 10 ... Raw material tank, 13 ... Raw material extraction piping, 15 ... Sealing chamber, 16 ... Circulation path, 17 ... Fin section, 18 ... Heater, 19,25 ... Piping, 20 ... Gas-liquid Separator, 26 …… Processing room, 27 …… MFC, 28 …… Sending and returning piping

Claims (1)

[Scope of utility model registration request] 1. An inert gas introducing pipe is connected to an upper space in a liquid raw material tank via a pressure control valve, and one end side of a liquid raw material extracting pipe is connected to a liquid raw material reservoir in the liquid raw material tank. Dip, the other end side of the liquid raw material extraction pipe is connected from the liquid raw material tank to the lower end of the sealed chamber, the circulation path through which the liquid heating medium circulates is extended from the outside of the sealed chamber into the sealed chamber, A heating means is provided in the external portion of the circulation path, and fin portions are formed at regular intervals in the sealed chamber portion, and a vaporized raw material transfer pipe is extended from the upper end of the sealed chamber and the tip thereof is vaporized. A gas raw material extraction pipe is connected to the separator and extends from the gas outlet of the gas-liquid separator, and a flow rate adjusting means is provided on the pipe, and the liquid raw material is fed from the liquid outlet of the gas-liquid separator. Extend the return pipe The tip evaporation gasometric take-out apparatus being characterized in that connected to the liquid material tank.