JP2970889B2 - Exhaust port structure of vacuum vessel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust port structure for a vacuum vessel.

[0002]

2. Description of the Related Art In general, for example, when a semiconductor product is manufactured, various vacuum vessels, for example, a film forming process or the like in each processing process in the manufacturing process, or a processing vessel or a stage preceding these processing vessels. There is a load lock chamber or the like to be arranged. By the way, in semiconductor manufacturing, how to improve the yield is a major problem. One of the countermeasures is to minimize the presence of particles that cause defective products in various processing processes. It has been made like that. For example,
Taking the above-mentioned load lock chamber as an example, the structure of the conventional exhaust port of this vacuum container is such that a main exhaust pipe 6 having a relatively large pipe diameter is directly connected to a rectangular parallelepiped opening by a flange 8 or the like as shown in FIG. Had been installed. And this main exhaust pipe 6
In addition, a bypass exhaust pipe 10 having a smaller pipe diameter and a smaller effective area is provided in parallel, and the inside of the vacuum vessel 2 is evacuated by a vacuum pump 12. The vacuum vessel 2 is configured to be able to accommodate the semiconductor wafer 14 while being supported by an arm or the like (not shown).

[0003]

When the vacuum vessel is evacuated, if the gas flow rate is excessively high, the particles in the vessel are wound up, and adhere to the surface of the semiconductor wafer to cause a defect. Therefore, when the inside of the container 2 is roughly evacuated from the atmospheric pressure, the evacuation speed is reduced by using the bypass exhaust pipe 10 having a reduced effective cross-sectional area to evacuate the gas, thereby reducing the gas flow velocity. Then, when the pressure in the container 2 has decreased to a certain extent, the bypass exhaust pipe 8 is switched to the main exhaust pipe 6 having a large effective judgment area to evacuate. However, the slow evacuation described above requires a relatively long time to reach a predetermined degree of vacuum, which has the advantage of reducing the throughput of semiconductor manufacturing.

[0004] A main exhaust pipe 6 is connected to the container bottom 4.
Is configured to be directly attached to the hole provided in the bottom 4 by the flange 8 or the like, so that a part of the gas flowing toward the bottom 4 In this case, turbulence is caused, and as a result, there is also an improvement in that particles are wound up. The present invention has been devised in view of the above problems and effectively solving them. An object of the present invention is to provide an exhaust port structure of a vacuum vessel in which the structure of the exhaust port is shaped so as to generate a laminar flow.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a structure of an exhaust port for exhausting gas in a vacuum vessel, wherein the diameter of the exhaust port is sequentially reduced along the exhaust direction. And the exhaust gas flowing through it into a laminar flow
It is configured to be formed in a funnel shape so as to maintain it .

[0006]

According to the present invention, as described above, when the gas in the vacuum vessel is discharged from the exhaust port, the opening area is gradually reduced in a funnel shape, so that the gas becomes laminar. As a result, the turbulence does not occur and the particles do not wind up.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the exhaust port structure according to the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIG. 1 and FIG. 2, in the present embodiment, a load lock chamber will be described as an example of a vacuum vessel. This load lock chamber 16
For example, the load lock chamber 16 is provided on one side with a gate valve 18 communicating with the atmosphere, and the other side is provided with a vacuum for processing a semiconductor wafer. Processing container 20
Are communicably connected via a gate valve 22. A transfer device 26 such as a robot arm for transferring a semiconductor wafer 24 as a transfer member is accommodated in the load lock chamber 16.
6 by bending the arm 28 of the processing container 2
The semiconductor wafer 24 can be taken in and taken out without opening the inside of the semiconductor wafer 24 to the atmosphere.

An exhaust port 30 is formed over substantially the entire bottom of the load lock chamber 16. FIG.
In order to prevent the drawing from becoming complicated,
FIG. 2 shows a perspective view of the load lock chamber 16 in which is omitted.
The partition wall 30a which defines the exhaust port 30 is made of, for example, stainless steel, and the diameter of the exhaust port 30 is reduced from the upper part downward, that is, in the exhaust direction, so that the exhaust port 30 is formed. It is formed in a funnel shape. The front opening 32 of the exhaust port 30 connected to the bottom of the load lock chamber 16 has an area large enough to contact four sides of the container bottom in order to increase the effective cross-sectional area of the exhaust. The front opening 32 has
For example, a large number of ventilation holes 34a are formed in a stainless steel plate or the like.
A baffle plate 34 having a constant aperture ratio is formed by forming a baffle plate, so that even if a turbulent flow occurs during evacuation below the baffle plate 34, it is possible to prevent the winding of particles from moving upward. It is configured. The aperture ratio of the baffle plate 34 is determined by the capacity of the vacuum vessel and the pumping speed so that turbulence does not occur during evacuation.
For example, it is preferably set to 50% or less.

An ordinary exhaust pipe 38 is connected to the reduced-diameter rear opening 36 at the other end of the exhaust port 30, and the vacuum vessel 16 is opened by a vacuum pump (not shown).
It is configured so that the inside can be evacuated. A drive source for the transfer device 26, for example, a motor 4 is provided below the baffle plate 34, that is, in the exhaust port 30 on the exhaust direction side.
0 is a plurality of motor support legs 4 inside the partition wall 30a.
2 and fixed. The drive shaft 40a of the motor 40 penetrates upward through the center of the baffle plate 34, and the arm 28 is attached thereto. A motor line 44 for supplying electric power to the motor 40
A water cooling pipe 48 penetrated through the partition wall 30a through a sealing member 46 and a coating 50
, So that the conduction heat of the motor transmitted through the motor wire 44 can be efficiently removed to the outside of the system.

Next, the operation of the embodiment constructed as described above will be described. First, the load lock chamber 16
When the semiconductor wafer 24 is accommodated in the inside, the gate valve 18 provided on this side is opened, and the arm 2 of the transfer device 26 is opened.
The semiconductor wafer 24 is taken into the inside from the clean room side at atmospheric pressure by using 8, and the gate valve 18 is closed to close the room.

Next, a vacuum pump (not shown) is driven to evacuate the load lock chamber 16 to a predetermined pressure. At this time, the gas in the room flows into the exhaust port 30 through the vent hole 34 a of the baffle plate 34 provided in the front opening 32 of the exhaust port 30, and flows down toward the rear opening 36 therein. . Here, since the exhaust port 30 has a large opening area of the front opening 32 and a large effective sectional area with respect to the container, it is necessary to relatively reduce the flow rate of the exhaust gas when the exhaust speed is the same. And the flow velocity can be made equal to or less than the Reynolds number at which turbulent flow occurs. In addition, since the exhaust port 30 is formed in a funnel shape along the exhaust direction, there is no corner at the attachment location, and the exhaust gas smoothly flows in a laminar flow state along the funnel shape, causing turbulence. The generation of flow is further suppressed.
Therefore, it is possible to prevent the particles from being wound up due to the turbulence. This means that turbulence does not occur even if the pumping speed is increased,
The time required for evacuation can be shortened.

In the case where the exhaust flow velocity increases and turbulence occurs to cause the particles to wind up, the turbulence is generated by the baffle plate 34 provided in the front opening 32 of the exhaust port 30.
Is prevented from passing through the baffle plate 34 and going upward, so that the wound-up particles do not adhere to the semiconductor wafer 24. Also, since the drive source, which is relatively easy to generate particles, ie, the motor 40, is provided below the baffle plate 34, the particles generated by this flow into the semiconductor wafer 24 by the action of the baffle plate 34. In addition, the generated particles are discharged to the exhaust pipe 38 as they are on the laminar flow flowing in the vicinity thereof.

The Joule heat generated by the motor 40 of the transporter 26 is in a vacuum atmosphere, so that heat dissipation by convection cannot be expected. However, the Joule heat is directly connected to the motor coil as a heat source and has relatively good heat conductivity. Since the motor wire 44 is integrally connected to the water cooling pipe 48, the motor 40 is effectively cooled, and therefore, it is possible to prevent the motor from being heated and damaged. . In particular, when the present embodiment is applied to a vacuum baking apparatus, the motor is exposed to severe thermal conditions.
Burnout and breakage of the motor can be reliably prevented. In this way, when the evacuation of the load lock chamber 16 is completed, the gate valve 22 is opened and the semiconductor wafer 2 is opened.
4 will be carried into the vacuum processing container 20. In the above-described embodiment, the exhaust port 30 having a circular cross section is provided at the rectangular bottom of the load lock chamber 16, but the present invention is not limited to this. You may comprise so that it may evacuate. In this case, since a place where dust such as particles accumulates completely disappears, generation of particles can be further suppressed.

The above embodiment can be applied not only to the load lock chamber but also to another vacuum vessel, for example, a reaction vessel. In this case, since the conductance of the exhaust gas is increased by the baffle plate, the evacuation from the atmosphere may be performed using the exhaust port having the structure of the present embodiment, and a separate vacuum exhaust port for extracting the reaction gas may be provided. Further, in the present embodiment, since the case where the present invention is applied to a load lock chamber is described, the transfer device 26 is provided, but the transfer device 26 may be omitted or the transfer device 26 and the baffle plate 34 may be provided. Even if it is not provided, the exhaust port 30 may simply be formed in a funnel shape.

[0015]

As described above, according to the present invention, the following excellent functions and effects can be exhibited. Since the exhaust gas from the vacuum vessel can be maintained in a laminar flow state, it is possible to prevent the particles from rolling up due to the turbulent flow. Further, since the pumping speed can be improved, the evacuation operation time can be reduced, and as a result, the throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an exhaust port structure of a vacuum vessel according to the present invention.

FIG. 2 is a perspective view showing an exhaust port structure shown in FIG.

FIG. 3 is a diagram illustrating a cooling structure of a motor wire of a transporter provided at an exhaust port.

FIG. 4 is a configuration diagram showing an exhaust port structure of a conventional vacuum vessel.

[Explanation of symbols]

 Reference Signs List 16 load lock chamber (vacuum container) 20 vacuum processing container 24 semiconductor wafer (transfer body) 26 transfer device 30 exhaust port 32 front opening 34 baffle plate 34a ventilation hole 36 rear opening 40 motor (drive source) 44 motor wire 48 water cooling pipe

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01J 3/00-3/08 H01L 21/205 H01L 21/265 H01L 21/285 H01L 21/302 H01L 21/31 H01L 21 / 68

Claims (4)

(57) [Claims] In the structure of an exhaust port for discharging gas in a vacuum vessel, the diameter of the exhaust port is sequentially reduced along the exhaust direction, and the exhaust gas flowing through the exhaust port is maintained in a laminar flow state.
Outlet structure of the vacuum vessel, characterized by being configured so as to form a funnel shape so that. 2. The exhaust port structure according to claim 1, wherein a baffle plate is provided at the exhaust port to prevent particles from being wound up from the exhaust port side to the inside of the vacuum vessel. . 3. The exhaust port is provided near a bottom of the vacuum vessel.
Claims characterized by being formed over the whole area
Item 3. The exhaust port structure according to Item 1 or 2. 4. The structure of an exhaust port for discharging gas from a vacuum vessel.
In the structure, the diameter of the exhaust port is sequentially changed along the exhaust direction.
While reducing the diameter to form a funnel, the exhaust port,
Particles from the exhaust port side to the inside of the vacuum vessel
A baffle plate for preventing winding-up is provided, and a drive source of a transfer device for transferring a transfer body into and out of the vacuum container is accommodated in the exhaust port on the exhaust direction side of the baffle plate. exhaust outlet structure shall be the.