KR100497982B1 - Composite dry vacuum pump having roots and screw rotor - Google Patents

Abstract

A dry vacuum pump mainly for evacuating the process chambers of semiconductor and display manufacturing apparatus or for discharging gaseous substances and / or process by-products generated from the process chamber to the outside, the partition wall between the roots type rotor and the screw type rotor An improved dry vacuum pump is disclosed having a structure that eliminates this need. The dry vacuum pump includes a lower portion of the root type rotor and a space in which a material to be sucked may remain in a portion of the lower portion of the screw type rotor connected to the root type rotor.

Description

COMPOSITE DRY VACUUM PUMP HAVING ROOTS AND SCREW ROTOR with Roots Rotor and Screw Rotor

The present invention mainly relates to a dry vacuum pump for evacuating the process chambers of semiconductor and display manufacturing apparatus or for discharging gaseous substances and / or process by-products generated in the process chamber to the outside.

Dry vacuum pumps are typically used to evacuate process chambers of semiconductor and display manufacturing apparatus. Alternatively, a dry vacuum pump is used to discharge gaseous substances and / or process byproducts produced in the process chamber described above. Such a dry vacuum pump uses a Roots type rotor, a screw type rotor, or a combination rotor thereof.

Recently, such dry vacuum pumps have a roots rotor with at least one lobe and at least one screw rotor for the purpose of maintaining a complete vacuum in the process chamber and reducing the required power costs. ). The Roots-type rotor is connected to the process chamber described above and used to suck and compress the process by-products including gaseous substances generated in the process chamber, and the screw-type rotor is used for the gas and process by-products sucked by the Roots-type rotor. It is used to vent out of one process chamber. In any case, these rotors are operated closed to maintain vacuum in the process chamber.

Typically, partitions are provided between these rooted rotor stages and screwed rotor stages to allow process by-products to move smoothly from the rooted rotor stage to the screwed rotor stage without disturbing the rotation of the rotor. A representative example of such a configuration is disclosed in U.S. Patent No. 5,549,463 to Kashiyama Industry Co., Ltd. (see FIG. 5 below).

According to this patent document, the dry vacuum pump 100 includes a pair of Roots-type rotors 102 and 103 and a pair of screw-type rotors 105 and 106. The pair of Roots-type rotors 102 and 103 and the pair of screw-type rotors 105 and 106 use a single drive motor 104, and the power generated by this drive motor 104 is three gears. 124, 125, and 127 are delivered to both the pair of Roots-type rotors 102 and 103 and the pair of screw-type rotors 105 and 106. Between the roots-type rotors 102 and 103 and the screw-type rotors 105 and 106, the partition 108 prevents process by-products from the process chamber as described above from being directly transferred to the screw-type rotors 105 and 106. This is provided. This patent is incorporated herein by reference in the present invention.

However, the partition 108 required in the dry vacuum pump 100 disclosed in the above-mentioned US Patent No. 5,549,463 is provided between the Roots-type rotors 102 and 103 and the screw-type rotors 105 and 106, namely And, since the housing 107 including them to be divided into several, it was a factor that increases the effort and the number of parts to manufacture such a dry vacuum pump 100.

In addition to the use of bulkheads, a variable pitch screw has been attempted to reduce the power consumption and increase the amount of process by-products compressed in dry vacuum pumps using a screw-type rotor. Effectiveness is estimated to be poor because of the need for larger rotors and pump housings.

In this situation, a simple method of directly connecting them without the bulkhead between the Roots-type rotors and the screw-type rotors has been attempted, but in this case, the gas and process by-products introduced into the Roots-type rotors must be moved to the screw every turn. However, a problem arises in that the rotation of the rotor is disturbed by the remaining process by-products.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to reduce the power consumption without using a partition wall between the Roots type screw and the screw type rotor by the process by-products such as compressed gas discharged It is to provide a dry vacuum pump of an improved structure that can increase the amount.

In order to achieve the above object, the present invention,

(a) a cylindrical housing on one side of which is provided a suction port for suctioning the substance to be sucked, and the other side of which is provided a discharge port for discharging the substance to be discharged;

(b) a Roots-type rotor accommodated in the housing and received in communication with the suction port;

(c) a screw-type rotor accommodated in the housing and disposed in proximity to the roots-type rotor;

(d) a shaft fixed through the center of the Roots-type rotor and the screw-type rotor and rotatably provided with the housing, the shaft being provided so that the inside and the outside of the housing are not in communication with each other; And

(e) a drive motor provided outside of the housing and connected to the shaft to drive the Roots-type rotor and the screw-type rotor in rotation;

Provided is a dry vacuum pump provided with a space for allowing a material to be sucked to remain in a lower portion of the root type rotor and a lower portion of the screw type rotor connected to the root type rotor.

As used herein, the term "substance to be absorbed" should be understood to include gaseous substances and / or process by-products generated in process chambers of semiconductor and display manufacturing devices.

The expression "shear side" as used herein, unless otherwise specified, refers to the inlet side on the basis of the inlet port through which the inhaled material is sucked in the dry vacuum pump according to the present invention and the outlet through which the compressed inhaled material is discharged. It should be understood to represent.

The expression "rear side" as used herein, unless otherwise specified, refers to the outlet side on the basis of an outlet through which the suction target material is sucked and a compressed suction target material discharged from the dry vacuum pump according to the present invention. It should be understood to represent.

Hereinafter, a dry vacuum pump according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in more detail.

1 schematically shows a cross section of a dry vacuum pump according to a preferred embodiment of the invention.

With reference to FIG. 1, a dry vacuum pump 1 according to a preferred embodiment of the invention has a Roots-type rotor 14 at its front end and a drive motor 26, preferably a water-cooled drive motor at its rear end. 26 has a screw-type rotor 18 between these roots-type rotors 14 and the drive motor 26. The screwed rotor 18 is coaxially coupled to the Roots-type rotor 14 with the aid of the shaft 24. Alternatively, the screwed rotor 18 may be coaxially coupled with the Roots-type rotor 14 without the aid of the shaft 24. For example, the roots-type rotor 14 and the screw-type rotor 18 may be manufactured integrally or separately and may be connected by connecting means such as welding. Such and modified modes of connection will be fully appreciated by those skilled in the art.

Roots-type rotors 14 and screwed rotors 18 are provided in the cylindrical housing 10. The housing 10 is provided with a suction port 12 for sucking the substance to be sucked into the vacuum pump 1 above the Roots-type rotor 14 in the drawing. This inlet 12 is directly hermetically connected to the process chamber because the material to be sucked in the process chamber (not shown) of the semiconductor or display manufacturing apparatus must be sucked into the vacuum pump 1. In general, the cylindrical housing 10 including the inlet 12 is hermetically connected to the process chamber of the semiconductor or display manufacturing apparatus, and foreign matters of the alien space are also included in the space outside the housing 10 except the housing 10. It is hermetically connected to prevent inflow. Of course, the portion through which the shaft 24 penetrates is also hermetically connected to be blocked by the outside world. The substance to be sucked through the inlet 12 is trapped between the lobes 14a and 14b provided in the roots-type rotor 14 by the rotation of the roots-type rotor 14 to move to the opposite side of the inlet 12. (See FIG. 1 and FIG. 2 Simultaneously).

The substance to be sucked into the vacuum pump 1 with the aid of the roots-type rotor 14 temporarily stays in a predetermined space (hereinafter referred to as "powder pool") indicated by reference numeral 16, and then the roots-type rotor ( It is oriented to the screw-type rotor 18 side by the pressure exerted by 14). The powder pool 16 has most of the space at the bottom of the rooted rotor 14 and some space at the bottom of the screwed rotor 18 as shown. The powder pool 16 provided in the lower portion of the root type rotor 14 and the screw type rotor 18 communicate with each other to form a space.

It should be noted here that the dry vacuum pump 1 according to the preferred embodiment of the present invention, unlike the conventional vacuum pump, does not have a partition between the Roots-type rotor 14 and the screw-type rotor 18. In the conventional vacuum pump, as described above, the partition wall is required to lower the power consumption of the vacuum pump and increase the amount of the suction object material, especially the gaseous material which is compressed and discharged. Conventionally, such a partition has allowed the housing to be divided into several compartments as described above, but such multiple compartmentalization of the housing has been a factor in increasing the number of parts. This requirement has been solved by the present invention. Specifically, in a preferred embodiment of the present invention, instead of using such a partition, one predetermined space 16 communicating with a lower part of the root type rotor 14 and a part of the lower part of the screw type rotor 18 is mutually communicated. That is, by providing a space called powder pool 16, it was possible to eliminate the requirement of the partition used in the prior art.

Referring back to FIG. 1, the suction object substance forced into the screw-type rotor 18 via the powder pool 16 is vacuum pumped by the one-way rotation of the screw-type rotor 18 and the pressure transmitted in the previous stage. Compressed discharge is carried out through the discharge port 20 provided on the rear end side of (1).

The shaft 24 provided through the cylindrical housing 10 is supported by the front side wall 28 and the rear end side wall 30 of the vacuum pump, respectively, with the aid of bearings 22a, 22b and 22c. In the figure, the shaft 24 right side shown on the right side is connected with the drive motor 26, in particular the water-cooled drive motor 26, and is rotated by its driving.

2 schematically shows the inside of the housing 10 of the dry vacuum pump 1 according to the invention. As can be seen from this figure, the dry vacuum pump 1 according to the present invention is a portion of the lower portion of the rooted rotor 14 and the lower portion of the screwed rotor 18 connected to the rooted rotor 14. By having a powder pool 16 which allows the material to be sucked to be delivered to the lower portion thereof by driving the Roots-type rotor 14 to stay for a while and then is oriented toward the screw-type rotor 18, the requirement of the partition wall required in the past Can be excluded. In this figure, a screw-type rotor 18 with a constant pitch is shown, but in order to increase the compression rate of the gas and / or process by-products, the pitch is not constant, i.e., the pitch increases from the inlet 12 to the outlet 20. It will be apparent to those skilled in the art that shorter screwed rotors 18 can also be used.

3 shows the driving principle of a Roots-type rotor 14 used in a dry vacuum pump 1 according to a preferred embodiment of the present invention.

Referring to FIG. 3, the material to be sucked sucked into the inside of the dry vacuum pump 1 according to the present invention through the suction port 12 has its lobe 14a by rotation of the Roots-type rotor 14 as shown. It is trapped between 14b and 14c and transported to a predetermined open space or space of a subsequent process. In the present invention, the material to be sucked is transferred to the powder pool 16 provided in the lower part of the root type rotor 14 and the lower part of the screw type rotor 18, and then provided to the screw type rotor 18 side. It is oriented through the powder pool 16 toward the screwed rotor 18. The principle of operation of the Roots-type rotor itself will be familiar to those skilled in the art.

4 schematically shows the main part of a dry vacuum pump according to a modified embodiment of the invention.

In a dry vacuum pump according to this modified embodiment, the gaseous substances and / or process by-products sucked through the inlet 12 are trapped in the free space between the lobes of the Roots-type rotor 14 as shown. The same as the dry vacuum pump according to the preferred embodiment of the present invention described above is transferred to the powder pool 16 'provided at the bottom, but a screw-type rotor is provided on both sides of the roots-type rotor 14, and the powder The difference is that the pool 16 'is in communication with a portion of the screw-type rotor and the aspirated gaseous material and / or process by-products are deflected in both directions. In this modified embodiment, an outlet (not shown) is provided on both sides as the gaseous material and / or process by-products are oriented in the direction of the screw rotor, ie in both directions, provided on both sides of the roots rotor 14. Will be. Further, the rotation of the screw-type rotors provided on both sides of the roots-type rotor 14 is carried out by one shaft 24 but the conveying orientation of their process by-products will depend on the position of the outlet provided. That is, the screwed rotor shown on the right side of the drawing will be provided to orient the process byproduct to the right, and the screwed rotor shown on the left side of the drawing will be provided to orient the process byproduct to the left. Other parts or components that are modified due to variations of this configuration will be fully appreciated by those skilled in the art having knowledge of the present specification.

As described above, the dry vacuum pump of the present invention does not use a partition wall between the Roots-type screw and the screw-type rotor, thereby preventing the increase in the number of parts due to compartmentalization of the housing, which is economically useful, and thus, the manufacturing process To be simplified.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously change and modify the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated.

1 is a schematic cross sectional view of a dry vacuum pump according to a preferred embodiment of the present invention;

FIG. 2 is a view schematically showing the inside of the dry vacuum pump shown in FIG. 1, in particular the inside of the housing; FIG.

3 shows the principle of operation of a Roots-type pump used in a dry vacuum pump according to a preferred embodiment of the present invention;

4 schematically illustrates a main portion of a dry vacuum pump according to a modified embodiment of the present invention; And

5 is a schematic cross-sectional view of a conventional dry vacuum pump.

* Description of the symbols for the main parts of the drawings *

1: dry vacuum pump 10: housing

12: suction port 14: Roots type rotor

16: powder pool 18: screw type rotor

20: outlet 22a, 22b, 22c: bearing

24 shaft 26 drive motor

28: front side wall 30: rear side wall

Claims (6)

A cylindrical housing 10 provided with a suction port 12 for sucking a substance to be sucked on one side and a discharge hole 20 for discharging the discharge target material on the other side; A roots-type rotor 14 accommodated in the housing 10 and accommodated in communication with the suction port 12; A screw-type rotor (18) accommodated inside the housing (10) and disposed close to the roots-type rotor (14); It is fixed through the center of the Roots-type rotor 14 and the screw-type rotor 18, rotatably provided with the housing 10, hermetically sealed so that the inside and the outside of the housing 10 does not communicate A shaft 24 provided; And It is provided on the outside of the housing 10, and is connected to the shaft 24 includes a drive motor 26 for rotationally driving the Roots-type rotor 14 and the screw-type rotor 18, Spaces 16 and 16 ′ in which a substance to be sucked may remain in a lower portion of the root type rotor 14 and a portion of the lower portion of the screw type rotor 18 connected to the root type rotor 14 are provided. Included dry vacuum pump. 2. Dry vacuum pump according to claim 1, characterized in that the space (16) (16 ') provided under the screwed rotor (14) is larger than the space (16) provided under the rooted rotor (14). 3. Dry according to claim 1 or 2, characterized in that the shaft (24) can rotate more smoothly with the aid of any one or more of the bearings 22a, 22b and 22c. Vacuum pump. The dry vacuum pump according to claim 1 or 2, wherein the drive motor (26) is a water-cooled drive motor. 4. The dry vacuum pump according to claim 3, wherein the drive motor (26) is a water-cooled drive motor. The dry vacuum pump according to claim 1 or 2, characterized in that the pitch of the screw-type rotor (18) becomes shorter from the inlet (12) to the outlet (20).