JP4633370B2 - Vacuum equipment - Google Patents

Description

  The present invention relates to a vacuum device, and more particularly to a vacuum device used in the field of manufacturing semiconductor devices and flat panel display devices.

  Vacuum equipment is used in many industrial fields in addition to the semiconductor manufacturing field.

  The vacuum apparatus generally includes a vacuum vessel and a vacuum pump that keeps the inside of the vacuum vessel in a vacuum or a reduced pressure state.

  The vacuum apparatus is arranged in a clean room and configured to perform a predetermined process while introducing and exhausting a predetermined process gas into the vacuum vessel.

  For example, Patent Document 1 discloses a vacuum apparatus having a plurality of stages of vacuum pumps used in the field of manufacturing semiconductor device manufacturing apparatuses.

  In this type of conventional vacuum apparatus, a high vacuum pump is connected to the reaction chamber as a first vacuum pump in order to reduce the pressure in the reaction chamber or to be in a vacuum state, and a second vacuum pump is provided after the high vacuum pump. As a booster pump and a third vacuum pump as a back pump.

In general, a high vacuum pump that operates in a molecular flow region at an ultimate pressure (10 ⁻⁷ Torr or less) is used as the high vacuum pump. Specifically, a turbo molecular pump or a thread groove pump is generally used as the high vacuum pump.

  The turbo molecular pump and the thread groove pump are generally small, but the exhaust speed is high, but the allowable back pressure is as low as 1 Torr or less (specifically 0.5 Torr or less). For this reason, one or two low vacuum pumps are provided in the subsequent stage of the high vacuum pump, while the ultimate pressure is relatively low, while operating at a relatively low back pressure.

  For example, when a two-stage vacuum pump is provided after the high vacuum pump, a booster pump or the like is provided as a medium vacuum pump after the high vacuum pump, and the ultimate pressure is low after the booster pump. A back pump (such as a roots type back pump) is provided as a low vacuum pump that operates at a relatively low back pressure.

  In many cases, the gas exhausted from the reaction chamber is discarded. However, particularly when a rare gas such as krypton or xenon is used for plasma excitation, it is usually performed to collect an expensive rare gas. In that case, the discharge side of the back pump is connected to the compressor of the recovery device. The compressor of the conventional recovery device simply stores the input gas, increases the pressure, and discharges it.

JP 2002-39061 A

  As described above, in a vacuum apparatus used for manufacturing a semiconductor device manufacturing apparatus, generally two to three vacuum pumps are used in multiple stages for one reaction chamber (vacuum vessel). These vacuum pumps are often different in structure from each other as described above, but in general, both are driven by an electric motor. For this reason, in this kind of vacuum apparatus with many vacuum pumps used, power consumption becomes large. Since the power consumption of the vacuum apparatus eventually affects the manufacturing cost of the semiconductor device manufacturing apparatus, it is desirable to reduce the power consumption.

  In particular, the last stage low vacuum pump (back pump) of the multi-stage vacuum pumps requires a large capacity, and thus consumes a large amount of power. Therefore, suppressing the power of the back pump is effective and desirable for reducing the power consumption of the entire vacuum apparatus, and thus for reducing the manufacturing cost of the semiconductor device manufacturing apparatus.

  Here, the reason for the high power consumption of the back pump is that, on the one hand, the discharge side is the atmosphere (atmospheric pressure is 760 Torr) to prevent back diffusion from the atmosphere side to the suction side (the reaction chamber is not in operation). (Even if there is any) Exhaust operation must be carried out. Secondly, the decompressed gas comes in from the suction side, but if the pressure is not increased above the atmospheric pressure, the gas will not enter the atmosphere. It is because it does not go out.

  Therefore, the subject of this invention is providing the vacuum apparatus and vacuum pump which can suppress power consumption.

  According to the present invention, a vacuum vessel having a gas inlet and a gas outlet, and at least one stage vacuum pump connected to the gas outlet of the vacuum vessel and keeping the inside of the vacuum vessel under reduced pressure or in a reduced pressure state And a compressor having the ability to depressurize the input side connected to the discharge port of the final-stage vacuum pump of the vacuum pumps.

  Depending on the amount of gas introduced into the vacuum device container and the capacity of the vacuum pump, the number of stages of the vacuum pump is one or more.

  In the present invention, it is preferable that a gas recovery device for recovering and reusing the gas discharged from the final stage vacuum pump is further installed, and the compressor is a gas recovery compressor in the gas recovery device.

  According to the present invention, a vacuum container having a gas inlet and a gas outlet, a multi-stage vacuum pump connected to the vacuum container and having a mechanical structure for reducing the pressure inside the vacuum container and maintaining a reduced pressure state, A vacuum device having a gas recovery device for recovering and reusing the gas discharged from the vacuum pump, connected to a discharge port of the final-stage vacuum pump, and assisting a decompression operation of the final-stage vacuum pump. In addition, a vacuum apparatus comprising a gas recovery compressor having a pressure reducing capability for suppressing back diffusion from the discharge port is obtained.

  When the supply amount of the gas introduced into the decompression device is smaller than a predetermined amount (in that case, the exhaust speed of the gas recovery compressor is relatively large, and the exhaust can be exhausted below the predetermined back pressure of the preceding vacuum pump. ), The final stage vacuum pump is omitted, the gas discharged from the final stage vacuum pump is recovered and reused by the gas recovery device, and the gas recovery compressor is connected to the front stage of the final stage. Connected to the discharge port of the vacuum pump.

  The multi-stage vacuum pump includes a first vacuum pump, a second vacuum pump connected to the subsequent stage of the first vacuum pump, and a third vacuum pump connected to the subsequent stage of the second vacuum pump. In this case, the first vacuum pump is a turbo molecular pump or a thread groove pump, the second vacuum pump is a booster pump, and the third vacuum pump is a dry pump. It is preferable. When the amount of gas to be introduced is less than the predetermined amount (in that case, the exhaust speed of the gas recovery compressor is relatively large, and the exhaust pressure can be reduced below the predetermined back pressure of the preceding vacuum pump) The third vacuum pump is omitted, and a compressor having a pressure reducing capacity is connected to the second vacuum pump.

  It can also be said that the compressor additionally attached to the discharge port of the last-stage pump, particularly the discharge port facing the atmosphere side, has the function of a vacuum pump.

  In the vacuum apparatus according to the present invention, a gas recovery compressor having the function of a vacuum pump or having a pressure reduction capability is connected to the discharge port of the final stage vacuum pump, so that the compressor performs the pressure reduction operation of the final stage vacuum pump. (Ie, a compressor having a pressure reducing capability lowers the pressure of the discharge port of the final stage vacuum pump, so that the final stage vacuum pump does not need to raise the pressure of the sucked gas above atmospheric pressure) and the final stage As a result of suppressing the reverse diffusion from the discharge port of the vacuum pump, the power consumption of the final stage vacuum pump can be suppressed as compared with the conventional case, and as a result, the manufacturing cost of the semiconductor device manufacturing apparatus can be reduced.

  Hereinafter, embodiments of the vacuum apparatus of the present invention will be described with reference to the drawings.

  Referring to FIG. 1, the vacuum apparatus includes a plurality of reaction chambers 10, 11, and 12 and each reaction chamber 10, 11, High vacuum pumps 1, 2, and 3 as first vacuum pumps arranged in one or a plurality of units in and 12 and booster pumps 4a and 5a as second vacuum pumps arranged in the subsequent stage of the high vacuum pump. And 6a and back pumps 4b, 5b and 6b as third vacuum pumps.

  Valves 22, 23 and 24 are provided between the high vacuum pumps 1, 2 and 3 and the booster pumps 4a, 5a and 6a.

  Furthermore, load lock chambers 13 and 14 for loading a workpiece such as a wafer into the reaction chambers 10, 11, and 12, and the workpiece loaded into the load lock chamber 13 are the reaction chambers 10, 11, and 12 and a transfer chamber 15 in which a robot (conveying device) for transferring from the reaction chambers 10, 11, and 12 to the load lock chamber 14 is housed.

  Further, a booster pump 8a, a back pump 8b, and a compressor 8c are connected to the load lock chamber 13, a booster pump 7a, a back pump 7b, and a compressor 7c are connected to the load lock chamber 14, and a booster is connected to the transfer chamber 15. A pump 9a and a back pump 9b are connected and configured to be able to be decompressed or in a vacuum state.

  Furthermore, although not shown, the reaction chambers 10, 11, and 12 are provided with heating means such as a gas inlet and a heater, and a predetermined process such as film formation while introducing a predetermined gas under heating. Is configured to be performed.

  In the figure, symbol A1 indicates piping between the high vacuum pumps 1, 2, and 3 and the booster pumps 4a, 5a, and 6a, and symbol A2 indicates reaction chambers 10, 11, and 12, and The piping between the high vacuum pumps 1, 2, and 3 is shown. In the figure, symbol R indicates a clean room.

  When the vacuum apparatus is in a standby state, the transfer chamber 15 and the reaction chambers 10, 11, and 12 are maintained at a reduced pressure or in a vacuum state.

  Then, a cassette containing a plurality of workpieces such as wafers is carried into the load lock chamber 13 from the atmosphere outside the apparatus, and the load lock chamber 13 is evacuated.

  Next, a gate valve (not shown) between the load lock chamber 13 and the transfer chamber 15 is opened, and the workpiece transfer robot picks up the workpiece in the cassette by the transfer arm and moves to the transfer chamber 15. Let

  Thereafter, a gate valve (not shown) between the reaction chamber 10 and the transfer chamber 15 is opened, and the object to be processed is placed on the stage in the reaction chamber 10 by the transfer arm.

  Then, after a predetermined process such as a film forming process, the processed object is transferred to another reaction chamber 11 or 12 or the load lock chamber 14 by a transfer arm.

  Then, after the processing is completed, the wafer is finally transferred from the load lock chamber 14 to the outside.

In the apparatus shown in FIG. 1, a high vacuum pump that operates in a molecular flow region at an ultimate pressure (10 ⁻⁷ Torr or less) is used as a high vacuum pump. Specifically, a turbo molecular pump or a thread groove pump is used as the high vacuum pump.

  The turbo molecular pump and the thread groove pump are generally small, but the exhaust speed is high, but the allowable back pressure is as low as 1 Torr or less (specifically 0.5 Torr or less). For this reason, one or two low vacuum pumps are provided in the subsequent stage of the high vacuum pump, while the ultimate pressure is relatively low, while operating at a relatively low back pressure.

  For example, when a two-stage vacuum pump is provided after the high vacuum pump, a booster pump or the like is provided as a medium vacuum pump after the high vacuum pump, and the ultimate pressure is low after the booster pump. A back pump (such as a roots type back pump) is provided as a low vacuum pump that operates at a relatively low back pressure.

  In the present invention, each of the back pumps 4b, 5b, 6b, 7b, 8b, and 9b, which is the final stage vacuum pump in FIG. 1, assists the decompression operation by the back pump or performs reverse diffusion from the discharge port. A gas recovery device B having compressors 7c, 8c, and 9c having a vacuum pump function or compressors 4c, 5c, and 6c having a vacuum pump function, which can be suppressed, is provided.

  In Embodiment 1 of the present invention, each of the back pumps 4b, 5b, 6b, 7b, 8b, and 9b in FIG. 1 has a screw pump.

  2A and 2B, in the screw pump, a male rotor 25 and a female rotor 26 are housed in a main casing 42, and a bearing is attached to an end plate 43 that seals one end of the main casing 42. 35 and 36 and bearings 37 and 38 attached to the sub casing 46 are rotatably supported.

  Timing gears 31 and 32 housed in the sub-casing 46 are attached to the rotation shafts 27 and 28 of the male rotor 25 and the female rotor 26, so that both the rotors 25 and 26 are not in contact with each other. The gap between them is adjusted. A motor M is attached to the rotating shaft of the male rotor 25 via a coupling or a gear for shifting. The rotation of the motor M is transmitted to the male rotor 25 and is transmitted to the female rotor via timing gears 31 and 32. The rotor 26 is configured to rotate.

  On one end side of the main casing 42, an air inlet 56 is provided and a sub casing 55 is attached. Further, the end plate 43 of the main casing 42 is formed with a discharge port 57 for discharging the gas compressed by the male rotor 25 and the female rotor 26.

  Further, since the temperature of the main casing 42 and the compressed gas rises due to the compression of the gas, a cooling jacket 33 is formed outside the main casing 42, and a coolant such as water is circulated in the cooling jacket 33. The main jacket 42 and the compressed gas are cooled.

  In the screw pump configured as described above, when the male rotor 25 is driven by the motor M, the female rotor 26 is rotationally driven by the timing gears 31 and 32. As the male rotor 25 and the female rotor 26 rotate, gas flows from the upper booster pumps 4 a, 5 a, 6 a, 7 a, 8 a, and 9 a (FIG. 1) through the suction port 56, and the male rotor 25, female rotor 26, and main It is sucked into the working chamber formed by the casing 42. The sucked gas is discharged through the discharge port 57 while being compressed as the male rotor 25 and the female rotor 26 rotate.

  Here, this vacuum apparatus is connected to the discharge port 57 of the screw pumps 4b, 5b, 6b, 7b, 8b, and 9b, suppresses reverse diffusion from the outside near the atmospheric pressure through the discharge port 57, and reduces power consumption. In order to reduce the pressure, a gas recovery device B including compressors 7c, 8c and 9c having a vacuum pump function or compressors 4c, 5c and 6c having a vacuum pump function is provided.

  As a result, the despreading of the back pumps 4b, 5b, 6b, 7b, 8b, and 9b is significantly reduced, and the power consumption can be greatly reduced. Further, the ultimate pressure of the compressors (4c, 5c, 6c, 7c, 8c, and 9c) having a vacuum pump function can be reduced to about 300 Torr.

  FIG. 3 shows the pressure at the suction port 56 of the screw pump and the consumption of the screw pump when the screw pump is used as the back pumps 4b, 5b, 6b, 7b, 8b and 9b in the vacuum apparatus shown in FIG. The result of verifying the relationship with electric power is shown. In this verification, when the discharge ports of the back pumps 4b, 5b, 6b, 7b, 8b, and 9b are exhausted by the compressors 4c, 5c, 6c, 7c, 8c, and 9c having the function of a vacuum pump, Measurement was performed when a compressor having a vacuum pump function was not attached to the discharge ports of the back pumps 4b, 5b, 6b, 7b, 8b, and 9b.

  As is clear from FIG. 3, the screw pump with the compressor having the vacuum pump function generally consumes less power regardless of the suction pressure than the screw pump without the compressor having the vacuum pump function. Low. In particular, when the suction pressure is 10 Torr or less, a screw pump equipped with a compressor having a vacuum pump function consumes approximately 50% less power than a screw pump not having a compressor having a vacuum pump function. .

  In other words, when a screw pump is applied as the back pumps 4b, 5b, and 6b of the vacuum apparatus as shown in FIG. 1, the gas chamber is not introduced into the reaction chambers 10, 11, and 12 (FIG. 1). High effect appears.

  Moreover, the number of stages of the vacuum pump in the vacuum apparatus according to the present invention is not limited to a multistage configuration, and may be two stages or one stage. That is, if the back pressure is in a pressure range where the effect of the compressor appears, the vacuum pump to which the compressor should be connected (final stage vacuum pump) is not limited to the back pump in the multi-stage configuration, but a two-stage vacuum pump. Or the first stage of a single-stage vacuum pump. The vacuum pump may be a vacuum pump of various types such as a roots type.

  Next, it will be specifically described that the back pump 4b at the final stage can be omitted when the supply amount of the gas introduced into the reaction chamber 10 of FIG. 1 is smaller than a predetermined amount.

  The predetermined amount of gas supply in this case is determined by various conditions, particularly the process pressure, the performance of the booster pump 4a (back pressure, exhaust speed, etc.) and the performance of the compressor 4c (pressure, exhaust speed, etc.). For example, if the process pressure is 5 Torr, the booster pump 4a has a back pressure of 200 Torr, the exhaust speed is 2000 L / min, the compressor 4c has a pressure of 200 Torr, and the exhaust speed is 50 L / min, the booster pump 4a has a back pressure of 200 Torr or less. Otherwise, the booster pump 4a has no performance, and the compressor 4c needs to discharge the pressure at the discharge port of the booster pump 4a to 200 Torr or less. The maximum amount of introduced gas at that time is expressed by the following equation: “introduced gas amount × 760 Torr (atmospheric pressure) ÷ exhaust speed of the compressor 4c 50L / min = 200 Torr (back pressure of the booster pump 4a)”. When calculated, the maximum amount of introduced gas is 13 L / min. When the reaction chamber 10 having the introduced gas amount of 13 L / min is evacuated by the booster pump 4a (back pressure 200 Torr, exhaust speed 2000 L / min), the chamber pressure becomes “introduced gas amount 13 L / min × 760 Torr (atmospheric pressure) ÷ booster pump. If the exhaust pressure of 4a is 2000 L / min = 5 Torr ”and the process pressure is 5 Torr or less, the amount of introduced gas can be 13 L / min. That is, under the above conditions, when the supply amount of the gas introduced into the reaction chamber 10 is 13 L / min or less, the back pump 4b in the final stage can be omitted and the high vacuum pump 1 can be omitted. The reaction chamber 10 can be exhausted by the pump (second vacuum pump) 4a and the compressor 4c.

  In the above embodiment, the vacuum device for manufacturing a semiconductor device has been described. However, the use of the vacuum device of the present invention is not limited to the semiconductor device manufacturing device, and is used in all industrial fields that require decompression. Can do.

1 is a schematic diagram showing a vacuum device for semiconductor manufacturing according to an embodiment of the present invention. (A) And (b) is sectional drawing which shows the screw pump as a vacuum pump of the last stage in the vacuum apparatus by the Example of this invention. It is a figure which shows the relationship between the suction pressure and the power consumption of a pump with a comparative example for demonstrating the effect of this invention.

Explanation of symbols

1, 2, 3 High vacuum pump 4a, 5a, 6a, 7a, 8a, 9a Booster pump 4b, 5b, 6b, 7b, 8b, 9b Back pump 4c, 5c, 6c, 7c, 8c, 9c Compressor 10, 11, DESCRIPTION OF SYMBOLS 12 Reaction chamber 13, 14 Load lock chamber 15 Transfer chamber 25 Male rotor 26 Female rotor 27, 28 Rotating shaft 31, 32 Timing gear 33 Water cooling jacket 42 Main casing 43 End plate 46, 55 Sub casing 56 Inlet 57 Outlet B Gas Recovery device

Claims (12)

A vacuum vessel comprising a gas inlet and a gas outlet; at least one vacuum pump connected to the gas outlet of the vacuum vessel and maintaining the vacuum vessel at a reduced or reduced pressure; and A vacuum apparatus comprising: a compressor for decompressing an input side , directly connected to an outlet of a vacuum pump of the last stage in a state where there is no inclusion and merging from another path .   The vacuum apparatus according to claim 1, wherein the number of stages of the vacuum pump is one or a plurality of stages depending on an amount of gas introduced into the vacuum apparatus container.   The vacuum apparatus according to claim 1, wherein the number of stages of the vacuum pump is plural. A gas recovery device for recovering and reusing the gas discharged from the final stage vacuum pump;
The vacuum apparatus according to any one of claims 1 to 3, wherein the compressor is a gas recovery compressor in the gas recovery apparatus. A vacuum container comprising a gas inlet and a gas outlet; a first vacuum pump for maintaining the inside of the vacuum container at a reduced pressure; a second vacuum pump connected to a subsequent stage of the first vacuum pump; A third vacuum pump connected to a subsequent stage of the second vacuum pump, and a compressor for reducing the pressure on the input side , directly connected to the discharge port of the third vacuum pump in a state where there are no inclusions and merging from other paths A vacuum apparatus characterized by comprising: The vacuum apparatus according to claim 5 , wherein the first vacuum pump is a turbo molecular pump or a thread groove pump, the second vacuum pump is a booster pump, and the third vacuum pump is a dry pump. The vacuum apparatus according to claim 5 or 6 , further comprising a gas recovery device for recovering and reusing the gas discharged from the third vacuum pump, wherein the compressor is a gas recovery compressor in the gas recovery device. . A decompression container having a gas introduction port and a gas discharge port in which a supply amount of gas to be introduced is less than a predetermined amount, a first vacuum pump for keeping the inside of the decompression container at a reduced pressure, and a first vacuum pump A second vacuum pump connected to the rear stage; and a compressor for reducing the pressure on the input side , which is directly connected to the discharge port of the second vacuum pump in a state in which no inclusions and other paths join together. Vacuum equipment. The vacuum apparatus according to claim 8 , wherein the first vacuum pump is a turbo molecular pump or a thread groove pump, and the second vacuum pump is a booster pump. A gas recovery device for recovering and reusing the gas discharged from the second vacuum pump;
The vacuum apparatus according to claim 8 or 9 , wherein the compressor is a gas recovery compressor in the gas recovery apparatus. Vacuum apparatus according to any one of claims 1 to 10 a vacuum pump connected to said compressor is a screw pump. The vacuum apparatus according to any one of claims 1 to 11, wherein the compressor and a vacuum pump to which the compressor is connected are connected in series.

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