JPH0531347A - Structure of exhaust port of vacuum container - Google Patents

Abstract

PURPOSE:To prevent the whirling-up of particles caused by turblent flow by forming an exhaust port to the bottom part of a vacuum container so as to have a funnel shape by successively reducing the caliber thereof along an exhaust direction and holding the gas discharged through the exhaust port to a laminar flow state. CONSTITUTION:An exhaust port 30 is formed to the bottom part of a load lock chamber (vacuum container) so as to have a funnel shape by successively reducing the caliber of the exhaust port 30 along an exhaust direction and the gas passed through the exhaust port to be discharged is held to a laminar flow state. As a result, the whirling-up of particles caused by turblent flow can be prevented. Since an exhaust speed can be increased, an evacuating operation time can be shortened and, as a result, throughput can be enhanced.

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 container.

[0002]

2. Description of the Related Art Generally, for example, in the case of manufacturing a semiconductor product, various vacuum containers, for example, a film forming process or the like, is used in each process in the manufacturing process, or a process container or a preceding stage of these process containers or the like. There is a load lock room, etc. to be placed. By the way, in semiconductor manufacturing, how to improve the yield is a big problem, and one of the countermeasures is to avoid particles that cause defective products from intervening in various processing processes as much as possible. It is done like this. For example,
Taking the above load lock chamber as an example, the structure of the conventional exhaust port of this vacuum container is such that the main exhaust pipe 6 having a relatively large pipe diameter is directly connected to the flange 8 etc. in the rectangular parallelepiped opening as shown in FIG. It was installed. And this main exhaust pipe 6
Further, the bypass exhaust pipes 10 having a smaller pipe diameter and a smaller effective area are provided in parallel, and the inside of the vacuum container 2 is evacuated by the vacuum pump 12. The vacuum container 2 is configured to be supported by an arm (not shown) or the like so that the semiconductor wafer 14 can be housed therein.

[0003]

By the way, when the vacuum container is evacuated and the flow velocity of the gas is excessively high, the particles in the container are wound up, which adheres to the surface of the semiconductor wafer and causes a defect. Therefore, when the inside of the container 2 is roughly evacuated from atmospheric pressure, the bypass exhaust pipe 10 having a narrowed effective cross-sectional area is used to reduce the evacuation speed to evacuate and thereby reduce the gas flow velocity. If the pressure in the container 2 has dropped to a certain extent, the bypass exhaust pipe 8 is switched to the main exhaust pipe 6 having a large effective judgment area for evacuation. However, in the slow vacuum evacuation as described above, it takes a relatively long time to reach a predetermined degree of vacuum, and there is an improvement point that the throughput of semiconductor manufacturing is reduced.

The main exhaust pipe 6 to the bottom 4 of the container is also provided.
Since the mounting structure is configured so as to be directly mounted in the hole provided in the bottom portion 4 by the flange 8 or the like, a part of the gas flowing toward the bottom portion 4 in the container 2 has a corner portion as in the illustrated example. There was also an improvement point that turbulence was caused in the result, and as a result, particles were wound up. The present invention has been made to pay attention to the above problems and to solve them effectively. An object of the present invention is to provide an exhaust port structure for a vacuum container in which the structure of the exhaust port is shaped so that a laminar flow is generated.

[0005]

In order to solve the above-mentioned problems, the present invention has a structure of an exhaust port for exhausting gas in a vacuum container, in which the diameter of the exhaust port is gradually reduced along the exhaust direction. It is configured to have a diameter and be formed into a funnel shape.

[0006]

Since the present invention is configured as described above, when the gas in the vacuum container is discharged from the exhaust port, the opening area of the funnel is gradually reduced, so that the gas becomes a laminar flow. As a result, the particles are discharged, turbulence does not occur, and particles do not wind up.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the exhaust port structure according to the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, in this embodiment, a load lock chamber will be described as an example of a vacuum container. This load lock chamber 16
The load lock chamber 16 is formed into a substantially rectangular parallelepiped shape, for example, and a gate valve 18 communicating with the atmosphere side is provided on one side of the load lock chamber 16, and a vacuum for processing a semiconductor wafer is provided on the other side. Processing container 20
Are connected via a gate valve 22 so that they can communicate with each other. Then, in the load lock chamber 16, a carrier 26 such as a robot arm for carrying the semiconductor wafer 24 as a carrier is housed.
By bending and extending the arm 28 of No. 6, the processing container 2
The semiconductor wafer 24 can be taken in and taken out without exposing the inside of 0 to the atmosphere.

An exhaust port 30 is formed over almost the entire bottom of the load lock chamber 16. Incidentally, FIG.
In order to prevent the drawings from becoming complicated,
The perspective view of the load lock chamber 16 which omitted is shown.
The partition wall 30a for partitioning and forming the exhaust port 30 is made of, for example, stainless steel or the like, and the exhaust port 30 is formed by sequentially reducing the diameter from the upper part to the lower part, that is, in the exhaust direction. It is formed like a funnel. The front opening 32 of the exhaust port 30, which is connected to the bottom of the load lock chamber 16, has a large area that is in contact with the four sides of the container bottom in order to increase the effective cross-sectional area of the exhaust. In this front opening 32,
For example, a large number of ventilation holes 34a are formed in a stainless steel plate or the like.
The baffle plate 34 having a constant aperture ratio is formed by forming the above, and it is possible to prevent the winding of particles from moving upward even if a turbulent flow is generated at the time of vacuum evacuation thereunder. It is configured. The aperture ratio of the baffle plate 34 is determined by the capacity of the vacuum container and the exhaust speed so that turbulent flow 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 a vacuum pump (not shown) is used to connect the vacuum container 16 to the vacuum container 16.
It is configured so that the inside can be evacuated. Then, below the baffle plate 34, that is, inside the exhaust port 30 on the exhaust side, a drive source of the carrier 26, for example, the motor 4 is provided.
0 is a plurality of motor support legs 4 inside the partition wall 30a.
It is attached and fixed via 2. The drive shaft 40a of the motor 40 passes through the center of the baffle plate 34 upward, and the arm 28 is attached to the drive shaft 40a. A motor wire 44 for supplying electric power to this motor 40
Is a water-cooling pipe 48 provided through the partition wall 30a through a seal member 46 and a coating 50 as shown in FIG.
Are integrally covered with the motor wire 44, and are configured 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 this embodiment configured as described above will be described. First, this load lock chamber 16
When the semiconductor wafer 24 is to be housed inside, the gate valve 18 provided on this side is opened, and the arm 2 of the carrier 26 is opened.
8 is used to take in the semiconductor wafer 24 from the clean room side at atmospheric pressure, and the gate valve 18 is closed to hermetically seal the room.

Then, by driving a vacuum pump (not shown), the load lock chamber 16 is evacuated to a predetermined pressure. At this time, the gas in the room passes through the vent holes 34a of the baffle plate 34 provided in the front opening 32 of the exhaust port 30 and flows into the exhaust port 30, and flows down into the rear opening 36. . Here, since the exhaust port 30 has a large opening area of the pre-stage opening 32 and a large effective cross-sectional area with respect to the container, when the exhaust speed is the same, the flow velocity of the exhaust gas should be relatively reduced. And the flow velocity can be made equal to or lower than the Reynolds number at which turbulence occurs. Moreover, since the exhaust port 30 is formed in a funnel shape along the exhaust direction, there is no corner at the attachment point, 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 rolled up due to the turbulent flow. This means that turbulence does not occur even if the exhaust speed is increased, and therefore
It is possible to shorten the time required for evacuation.

When the exhaust flow velocity is increased and turbulent flow is generated to cause particles to be wound up, the turbulent flow is provided by the baffle plate 34 provided at the front opening 32 of the exhaust port 30.
By the action of, the baffle plate 34 is prevented from passing through and going above the baffle plate 34, and as a result, the particles wound up do not adhere to the semiconductor wafer 24. Further, since the drive source that relatively easily generates particles, that is, the motor 40 is provided below the baffle plate 34, the particles generated from this flow into the semiconductor wafer 24 side by the action of the baffle plate 34 described above. In addition, the generated particles ride on the laminar flow in the vicinity thereof and are exhausted as they are to the exhaust pipe 38.

The Joule heat generated by the motor 40 of the carrier 26 is in a vacuum atmosphere, and therefore heat dissipation due to convection cannot be expected, but it is directly connected to the motor coil serving as a heat source and has relatively good thermal conductivity. Since the motor wire 44 is integrally connected with the water cooling pipe 48, the motor 40 is effectively cooled, and therefore, it is possible to prevent heat from being accumulated in the motor and damaging it. . In particular, when the present embodiment is applied to a vacuum baking apparatus, the motor is exposed to severe thermal conditions,
It is possible to reliably prevent burnout and damage of the motor. When the evacuation of the load lock chamber 16 is completed in this way, the gate valve 22 is opened to open the semiconductor wafer 2
4 will be carried into the vacuum processing container 20. Although the exhaust port 30 having a circular cross section is provided in the rectangular bottom of the load lock chamber 16 in the above-described embodiment, the present invention is not limited to this. It may be configured to evacuate. In this case, the place where dust such as particles accumulates is completely eliminated, so that the 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 container, for example, a reaction container. In this case, the baffle plate increases the conductance of the exhaust gas. Therefore, for evacuation from the atmosphere, the evacuation port having the structure of this embodiment may be used, and the evacuation port for drawing the reaction gas may be separately provided. Further, in the present embodiment, the case where the carrier 26 is provided because the case where it is applied to the load lock chamber is described. However, the carrier 26 may be omitted, or the carrier 26 and the baffle plate 34 may be omitted. 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 operational effects can be exhibited. Since the exhaust gas from the vacuum container can be maintained in a laminar flow state, it is possible to prevent particles from rolling up due to turbulent flow. Further, since the evacuation rate can be improved, the vacuuming operation time can be shortened, and as a result, the throughput can be improved.

[Brief description of drawings]

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

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

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

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

[Explanation of symbols]

16 load lock chamber (vacuum container) 20 Vacuum processing container 24 Semiconductor wafer (carrier) 26 carrier 30 exhaust port 32 Front opening 34 baffle board 34a vent 36 Rear opening 40 motor (drive source) 44 motor wire 48 water cooling pipe

Claims (3)

[Claims] 1. A structure of an exhaust port for exhausting gas in a vacuum container, wherein the diameter of the exhaust port is gradually reduced along the exhaust direction to form a funnel shape. Vent structure of container. 2. The exhaust port structure according to claim 1, wherein the exhaust port is provided with a baffle plate for preventing particles from being wound up from the exhaust port side to the inside of the vacuum container. . 3. The drive source of a carrier for loading and unloading a carrier into and from the vacuum container is housed in the exhaust port on the exhaust side of the baffle plate. Exhaust structure.