JP2012049405A - Pump applied to semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump applied to a semiconductor manufacturing apparatus of which cleaning efficiency is improved so that products deposition within the pump is reduced, the life of the pump is extended, and manufacturing efficiency of semiconductors is increased.SOLUTION: A valve 25 is opened upon receiving a cleaning command signal 35. Then, nitrogen gas heated by a heater 23 is introduced into a dry pump 13, for example, at a flow rate of 40 L/min. The heater 23 is controlled through a thermocouple (not shown) and heated, for example, to about 200°C all the time. With heated nitrogen gas introduced into dry pump 13, the internal temperature can increase to about 100°C during a cleaning period, while the internal temperature is as low as about 80°C during a processing period. Thus, by allowing the temperature within the dry pump 13 to be increased only during a cleaning period, cleaning gas can be operated efficiently, and the removal of deposition can be facilitated.

Description

  The present invention relates to a pump applied to a semiconductor manufacturing apparatus, and in particular, improves the cleaning efficiency, thereby reducing product accumulation inside the pump, extending the life of the pump, and increasing the semiconductor manufacturing efficiency. The present invention relates to a pump applied to the apparatus.

In the manufacturing process of a semiconductor device, a CVD (Chemical Vapor Deposition) process is performed in which a semiconductor, an insulator, a metal film or the like is deposited on a semiconductor wafer and is formed using a chemical vapor reaction. Gas is being used.
When this gas is cooled, the film and powder contained in the gas are solidified and adhered to the inside of the reaction chamber other than the semiconductor wafer, the exhaust pipe, the pump, and the like.

  For this reason, in the conventional semiconductor device manufacturing process, cleaning gases such as ClF3, NF3, and HCl are periodically applied at the end of the process according to the types of products generated at the time of film formation of the semiconductor wafer and adhered to each part. The reaction chamber, the exhaust pipe, the pump, and the like of the semiconductor processing apparatus are cleaned by introducing them into the process chamber and decomposing and discharging the deposits (see Patent Document 1). And these cleaning gas can function decomposition | disassembly and discharge | emission of a deposit | attachment efficiently, so that it is 100 degreeC or more.

Japanese Patent No. 3456933

  By the way, in recent years, since the number of semiconductor wafers per processing step is greatly increased and miniaturization is required, various gases are often used more than ever. Among these, with a specific gas species containing a component such as tungsten, a metal film such as tungsten is deposited and deposited inside the pump unless the pump is operated at a low temperature of 80 ° C. or lower during the processing of the semiconductor wafer. It leads to short life.

However, if the temperature is kept at a low temperature of 80 ° C. or lower during the subsequent cleaning process, the cleaning gas does not function efficiently due to the low temperature, so that the necessary deposits are decomposed and discharged. Will take a lot of time.
In addition, such a long cleaning time may reduce the time that can be used for the process, and may reduce the manufacturing efficiency.

  The present invention has been made in view of such a conventional problem. By improving the cleaning efficiency, product accumulation inside the pump is reduced, the pump life is increased, and the semiconductor manufacturing efficiency is increased. Another object of the present invention is to provide a pump applicable to a semiconductor manufacturing apparatus.

  Therefore, the present invention (Claim 1) is a pump for sucking a used gas used in the process of semiconductor processing from the chamber, and is supplied from the chamber to the pump during the semiconductor processing process. A process gas that flows, a cleaning gas that flows from the chamber to the pump during a cleaning period after the end of the process treatment period, a heating unit that heats the cleaning gas, and a heating unit that heats the cleaning gas during the cleaning period. And a control means for making the temperature of the cleaning gas higher than the temperature of the process gas by a predetermined value or more.

By raising the temperature inside the pump only during the cleaning period, the cleaning gas can function efficiently and deposits can be easily removed.
On the other hand, since the inside of the pump can be kept at a low temperature during the process treatment period, even if the process gas is introduced into the pump, it can be prevented that it is deposited as metal inside the pump. Therefore, the life of the pump can be extended. In addition, in order to make the inside of a pump low temperature, you may make it arrange | position cooling equipments, such as a water cooling pipe, separately.

  The present invention (Claim 2) is characterized in that the heating means raises the temperature of the cleaning gas by heating a predetermined gas and mixing it with the cleaning gas.

  The predetermined gas is preferably an inert gas. The temperature of the cleaning gas can be directly increased by mixing a predetermined gas with the cleaning gas after heating. Therefore, the cleaning gas can function efficiently in a short time.

  Furthermore, the present invention (Claim 3) is characterized in that the heating means raises the temperature of the cleaning gas in contact with the stator by heating the temperature of the stator.

  The temperature of the stator may be heated by a heater or the like.

  Furthermore, the present invention (Claim 4) is characterized in that the stator is heated by heat conduction by controlling the water temperature for cooling the pump.

  Existing water can be used for pump cooling water. In this case, the stator can be heated with some modifications of the control circuit.

  Furthermore, the present invention (Claim 5) is characterized in that the process gas contains tungsten.

  By operating the pump at a low temperature during the process processing period and at a high temperature during the cleaning period, metal deposition and deposition can be efficiently prevented even when tungsten is included in the process gas.

  As described above, according to the present invention, the temperature of the cleaning gas is set to be higher than the temperature of the process gas by a predetermined value or more during the cleaning period by heating by the heating means, so that the cleaning gas functions efficiently, Deposits can be easily removed.

  On the other hand, since the inside of the pump can be kept at a low temperature during the process treatment period, even if the process gas is introduced into the pump, it can be prevented that it is deposited as metal inside the pump.

Overall system configuration diagram of the first embodiment of the present invention Conceptual diagram of dry pump Equipment process timing chart Dry pump internal temperature timing chart Pump temperature rise timing chart The conceptual block diagram of 2nd Embodiment of this invention. Diagram showing temperature adjustment of stator part

Hereinafter, embodiments of the present invention will be described. FIG. 1 shows an overall system configuration diagram of the first embodiment of the present invention.
In FIG. 1, a semiconductor wafer 3 is housed inside a process chamber 1, and various gases are supplied from the outside for process processing through a gas pipe 5, and a cleaning gas is supplied. A turbo molecular pump 9 is flanged from the process chamber 1 via a gas pipe 7, and the process chamber 1 is decompressed to a high vacuum by the turbo molecular pump 9. However, the turbo molecular pump 9 may be omitted.

  The gas that has been processed inside the process chamber 1 is introduced into the dry pump 13 further downstream by the connection of the gas pipe 11 via the turbo molecular pump 9. In the dry pump 13, the sucked gas is gradually pressurized in, for example, five stages. The gas pressurized to near atmospheric pressure by the dry pump 13 is then detoxified by the detoxifying device 17 through the gas pipe 15 and then discharged into the atmosphere.

  FIG. 2 shows a conceptual configuration diagram of the dry pump. A water pipe 19 is disposed on the outer periphery of the dry pump 13 so as to be cooled with water. As shown in a timing chart to be described later, after the process gas mixed with tungsten is sucked into the gas pipe 11 for a certain period of time, different types of gases are introduced into the process chamber 1 such that the cleaning gas is sucked at the next certain time. Further, the gas is alternately sucked through the turbo molecular pump 9.

  A nitrogen gas supply pipe 21 is branched in the middle of the gas pipe 11, and nitrogen gas heated by the heater 23 is introduced into the dry pump 13 through the valve 25. At this time, it is mixed with the cleaning gas supplied from the gas pipe 11 side.

Next, the operation of the first embodiment of the present invention will be described.
FIG. 3 shows an apparatus process timing chart. As shown in the process timing chart in the upper part of FIG. 3, the CVD process is performed about 10 times when the number of semiconductor wafers is 10 based on the process command signal 33 from the control device 31. One of the pulses in FIG. 3 corresponds to this one process. Thereafter, a cleaning start signal which is a cleaning command signal 35 is transmitted from the control device 31 toward the dry pump 13.

  Upon receipt of the cleaning command signal 35, the valve 25 is opened. At this time, nitrogen gas heated by the heater 23 is introduced into the dry pump 13 at a flow rate of, for example, 40 liters / minute and mixed with the cleaning gas. The heater 23 is controlled by a thermocouple (not shown) and is always heated to about 200 ° C., for example.

  Since the heated nitrogen gas is introduced into the dry pump 13, the internal temperature is as low as about 80 ° C. during the process period as shown in the dry pump internal temperature timing chart of FIG. The internal temperature can be increased to about 100 ° C.

  FIG. 5 shows a detailed timing chart of pump temperature rise at this time. For example, the temperature rise is completed to about 100 ° C. in about half of the cleaning period after receiving the cleaning start signal, and the cleaning stop signal is similarly sent. After the valve 25 is closed, the water pipe 19 is cooled with water, so that the temperature drop is completed to about 80 ° C. during the process in about half the cleaning period.

In this way, by raising the temperature inside the dry pump 13 only during the cleaning period, the cleaning gas can function efficiently and deposits can be easily removed.
On the other hand, since the inside of the dry pump 13 can be kept at a low temperature during the process processing period, even if a process gas mixed with tungsten is introduced into the dry pump 13, it is possible to prevent tungsten from being deposited as a metal inside the pump. it can.

  Assuming that the internal temperature is as low as about 80 ° C. even during the cleaning period, for example, when the cleaning is expected to achieve the same removal effect as when the internal temperature is 100 ° C., for example, about three times as much. Cleaning time is required. Therefore, extra cleaning gas is required. This cleaning gas is expensive, and the manufacturing cost becomes high because the processing process is not time-consuming.

  However, as in this embodiment, the internal temperature of the pump is increased to about 100 ° C. during the cleaning period, so that the cleaning process is made more efficient, the product accumulation inside the pump is reduced, and the cleaning time is shortened. Is done. For this reason, a lot of time can be spent on the process processing, and the manufacturing efficiency can be increased.

Moreover, the lifetime of the pump can be extended by reducing the product accumulation inside the pump.
In order for the cleaning gas to function efficiently, it is desirable that the internal temperature of the pump be about 100 ° C. to 120 ° C.

Next, a second embodiment of the present invention will be described.
In the first embodiment of the present invention, the heated nitrogen gas is mixed with the cleaning gas to increase the internal temperature of the pump during the cleaning period. However, in this embodiment, the cleaning is performed by increasing the stator temperature. The internal temperature of the pump was raised during the period.

  FIG. 6 shows a conceptual configuration diagram of the second embodiment of the present invention. As shown in FIG. 6, a water pipe 19 is disposed on the outer periphery of the dry pump 13, the motor 14, and the inverter 16, and water cooling is performed. Since the dry pump 13 has two systems of compression functions, the water pipe 19 is also supplied to the two systems. The temperature of this water is raised by controlling a thermocouple 41 built in the dry pump 13, and a stator (not shown) inside the dry pump 13 is heated by heat conduction.

  Specifically, as shown in FIG. 7, during the process processing period, the amount of water flowing in the dry pump 13 by on / off control of the valve 43 by the thermocouple 41 is adjusted so that the temperature of the stator portion becomes about 80 ° C. To control.

  On the other hand, during the cleaning period, the setting of the thermocouple 41 is raised to about 100 ° C., which is a different temperature. At this time, the amount of water flowing by the on / off control of the valve 43 is adjusted to be less than that at 80 ° C., and the temperature of the stator portion is controlled to be about 100 ° C. When the temperature of the stator portion reaches about 100 ° C., the cleaning gas is heated to about 100 ° C. by contacting the stator portion.

In the second embodiment, the existing equipment used for the original water cooling can be used as the water pipe for cooling the pump. And the existing thing can be utilized also about the water temperature control during a process processing period. As for the water temperature control during the cleaning period, the stator can be heated with some modifications of the control circuit.
As a result, the same effect as that of the first embodiment can be obtained by simple modification.

DESCRIPTION OF SYMBOLS 1 Process chamber 3 Semiconductor wafer 5, 7, 11, 15 Gas pipe 9 Turbo molecular pump 13 Dry pump 17 Detoxifier 19 Water pipe 21 Nitrogen gas supply pipe 23 Heater 25, 43 Valve 31 Controller 33 Process command signal 35 Cleaning command Signal 41 Thermocouple

Claims (5)

A pump for sucking a used gas used in the process of semiconductor processing from a chamber,
A process gas flowing from the chamber to the pump during a process period of the semiconductor process;
A cleaning gas flowing from the chamber to the pump during a cleaning period after the end of the process period;
Heating means for heating the cleaning gas;
A pump applied to a semiconductor manufacturing apparatus, comprising: a control unit that raises the temperature of the cleaning gas by a predetermined value or higher than the temperature of the process gas during the cleaning period by heating by the heating unit.   2. The pump applied to a semiconductor manufacturing apparatus according to claim 1, wherein the heating means heats a predetermined gas and then mixes it with the cleaning gas to raise the temperature of the cleaning gas.   2. The pump applied to a semiconductor manufacturing apparatus according to claim 1, wherein the heating means raises the temperature of the cleaning gas in contact with the stator by heating the temperature of the stator.   4. The pump applied to a semiconductor manufacturing apparatus according to claim 3, wherein the stator is heated by heat conduction by controlling the water temperature for cooling the pump.   5. The pump applied to a semiconductor manufacturing apparatus according to claim 1, wherein the process gas contains tungsten.

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