JP3025591B2 - Magnetic levitation transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation transfer device for transferring a wafer or a substrate in a semiconductor manufacturing facility or the like.

[0002]

2. Description of the Related Art In the production of recent high-precision semiconductors such as wafers and substrates, for example,
It is required to maintain an extremely high dust-free environment, and each step needs to be performed in a high vacuum atmosphere consistently throughout. In this way, high vacuum, high dust free environment,
That is, by maintaining the state of a high clean room, it is possible for the first time to manufacture a product by a complicated advanced technology such as a wafer. In addition, during this process, in order to transport semi-finished products or finished products in the ultra-high clean room, the transport path interconnecting these ultra-high clean rooms is also subject to a highly dust-free environment. It is necessary to absolutely prevent the generation of dust due to the transport equipment moving in the transport path coming into contact with each other in the transport path. Further, in order to make the inside of the transfer path a high vacuum, the transfer path is externally heated to about 250 ° C.
It is also necessary to carry out a so-called baking step, in which the various members in the transport path need to withstand this high temperature.

That is, in the manufacture of semiconductors and the development of superconductors and the like, a high vacuum atmosphere is widely used. For this reason, various processing apparatuses operating under such a high vacuum atmosphere, Various equipments are shielded or shielded from the outside world, and high vacuum, for example, 10-
It is installed and placed in a sealed space maintained under a vacuum of 10 Torr (Torr) or less, and these various processing devices and equipment are connected by a sealed transfer passage maintained under a high vacuum atmosphere. After the materials to be processed are inserted into the enclosed space from the above, these materials are processed in the enclosed space, and then transferred to the transport case traveling in the closed transport path, and the transport case allows other travel. It is necessary to transport the finished products or intermediate products processed in this way to various processing devices and equipment, or to take out the finished products or intermediate products thus processed from the processing devices to the outside again through a closed transport path. In this case, it is necessary to remotely control various devices, devices, transport cases, and the like from outside the closed container.

As a method of manufacturing a wafer, instead of such a manufacturing method under an ultra-high vacuum, a method of blowing a gas to the back surface of the wafer and transporting the wafer in a floating state is known. In this method as well, it is required that there is no contact between the wafer and the transfer path, and that the wafer can be continuously transferred at a high speed. In particular, it has been reported that in this method, oxidation of the wafer surface can be prevented by using ultra-high purity N2 as a carrier gas. (References: "Microelectronic Circuit Experimental Facility Research Report" No. 3 "Super Clean Technology Special": Research Institute of Electrical Communication, Tohoku University:
1990).

[0005] The applicant of the present invention has disclosed, in particular, Japanese Patent Application No. Hei.
No. -4765, invention of a "floating-type article transfer device in vacuum" (patent filed on January 113, 2001)
No. 04 (hereinafter referred to as "the prior invention").

That is, as shown in FIGS. 4 and 5 of the accompanying drawings, the "floating type article transfer device in a vacuum" according to the prior invention has a circular cross section having a closed transfer passage maintained at a high vacuum inside. A transfer case (floating shuttle) 51 for placing, for example, a wafer for semiconductor manufacturing is arranged inside a certain magnetic levitation transfer tube 50. The transfer case 51 has a substantially rectangular planar outline. The base plate 52 and the transfer case lower base plate 53 are formed by integrally connecting the transfer case 50 at a vertical interval, and the transfer case upper base plate On the upper surface of the top surface 52, near each end in the longitudinal direction, a column 54 is vertically installed, and on the top thereof, a long plate-shaped high magnetic material ( Iron piece) 5 Are respectively mounted horizontally, and near the upper end of the transfer case upper base plate 52 and the lower end of the transfer case lower base plate 53 near one longitudinal end, the vertical center plane XX of the transfer pipe 50 is respectively provided. In the plane, a pair of insulating posts 56 are respectively mounted symmetrically with respect to the vertical center of the posts 54, and the upper and lower portions serving as displacement sensors are respectively attached to the ends of these insulating posts 56. The pole plates 57 and 58 are fixed horizontally. In addition, a pair of mutually fixed parallel fixed electrode plates 59 cooperating with these electrode plates 57, 58 are insulated via insulating posts 60.
It is installed continuously on the inner wall of the transfer pipe 1 in the longitudinal direction.

A driving carriage 70 is disposed on the top of the outside of the transfer tube 50, and is substantially U-shaped symmetrically with respect to the vertical center plane XX of the transfer tube 50. It has a rectangular cross section and a rectangular contour in a plane, and is arranged so as to be movable in the longitudinal direction of the transport pipe 50. And, on the lower surface of the driving bogie 70,
Near the end in the longitudinal direction, the electromagnet (A) 71 and the electromagnet (B) 72 form the vertical center plane XX of the transport pipe 50.
So that each of them has a center therein and corresponds to the position of each iron piece 55 attached to the transfer case 51, that is, as a set of electromagnets (A) 711 and 712 and electromagnets (B) 721 and 722, It is attached to.

Further, the drive carriage 70 has a lower surface,
Almost symmetrically with respect to the vertical center plane XX of the transport pipe 50,
Near one of the longitudinal edges, a pair of guide rollers 73 are rotatably arranged at intervals in the longitudinal direction, and near the other longitudinal edge,
At the center in the longitudinal direction, a slider 751 of a two-phase excitation type linear pulse motor 75 having a substantially longitudinal cross section is attached in the longitudinal direction. on the other hand,
A pair of pedestals 76 having an inverted L-shaped cross section at the top of the outer side of the transfer pipe 50 and spaced from its vertical center plane XX have their horizontal leg portions 761 in the same horizontal plane. One horizontal leg portion 761
A guide rail 7 having an L-shaped cross section
7 are continuously fixedly arranged in the longitudinal direction of the transport pipe 50 by the horizontal leg portions 771, and the vertical leg portions 71
The guide roller 73 of the drive carriage 70 is supported by the top edge of the drive carriage 70, and a rail for guiding the linear pulse motor 75 is provided above the other horizontal leg portion 761 of the mount 76. Corresponding scale 752 of linear pulse motor 75 having a substantially rectangular cross section
Are continuously and fixedly arranged in the longitudinal direction of the transport pipe 50 so as to overlap with each other in the vertical direction on the slider 751.

In this manner, the drive bogie 70 has a lower surface on one side in the longitudinal direction formed by the guide roller 73 and the top edge of the vertical leg portion 772 of the guide rail 77, and a linear pulse on the other side. A slider 751 for the motor 75;
The scale is maintained horizontally by the scale 752. In this case, the electromagnet (A) 71 and the electromagnet (B) 72
Urges the transfer case 5 by its magnetic force.
The top iron piece 55 is sucked through the wall of the transfer tube 50 so that the transfer case 51 can be floated inside the transfer tube 50 to an arbitrary height. When the linear pulse motor 75 is energized, the driving bogie 70
Is guided by the guide rail 77 and the scale 752 of the linear pulse motor 75, and moves in the horizontal direction along the transport pipe 50.

Further, in the “floating type article transport device in vacuum” according to the prior invention, the floating level of the transport case 51 in the transport path 50 is formed by the electrode plates 57, 58 and the fixed electrode plate 59. The transfer case 51 is detected by a displacement sensor composed of a capacitance detection mechanism, and is moved in the length direction of the transfer pipe 50 while maintaining the detection position by a relay and a control circuit (not shown). I have.

The transfer case 51 according to the prior invention
FIG. 6 shows the transfer operation pattern qualitatively shown by taking the time on the horizontal axis and the speed and the flying position on the vertical axis. That is, as can be seen from this figure, at the start of the operation, the transfer case 51 which was initially at the stationary position.
Is gently lifted, when reaching a predetermined height, accelerated at a constant acceleration, after reaching a predetermined speed, propelled at a constant speed, in this way, when approaching a predetermined stop position, The vehicle decelerates at a constant deceleration so as to stop at that position, and stops at a predetermined position, and at the same time, descends gently. It is easy to make these processes automatically proceed in accordance with an arbitrary pattern program input to the linear pulse motor 75 and the magnetic levitation control device.

[0012]

However, in the "article conveying device in a floating vacuum" according to the prior invention,
The following problems were found. With the magnetic levitation method, it is difficult to perform a stationary operation accurately, and even if the driving truck on the atmosphere side stops accurately, the transfer case on the vacuum side does not stop swinging. (To solve this, it is conceivable to install a permanent magnet in the carrying case and generate eddy current on the capacitance rail to brake it, but due to the dimensions of the rail, There is no way to gain power.) The floating level of the transfer case is detected by a displacement sensor consisting of a position detection mechanism based on capacitance.However, if the sensitivity of the capacitance sensor is increased, even a change in capacitance due to discontinuity in the shape of the transfer passage or vacuum vessel is detected. And that the optimum sensitivity band is narrow, adjustment is delicate, and there is a surface lacking in transport stability.

Accordingly, the present invention is to provide a magnetic levitation transfer device which can solve the above-mentioned problems in the above invention and can be used as a wafer airflow transfer system of ultra-high purity N2. , The issues to be solved.

[0014]

According to the present invention, there is provided a magnetic levitation transfer apparatus comprising: a closed transfer path which is maintained in a high vacuum or is filled with a high-purity gas; It consists of a drive cart that can be driven along the passage, and a transfer case that is movably arranged in the closed transfer passage, and a ferromagnetic material is attached to the top of the transfer case. In a magnetic levitation transfer device in which the body is attracted and moved by an electromagnet attached to the lower surface of the drive cart, the transfer case is lifted and moved in the closed transfer passage. A magnet for detection is attached, and a magnetic sensor for position detection is attached to the drive bogie so as to face the magnet for position detection with a wall of the closed conveyance passage therebetween, and A high-flux-density magnet is attached to the lower surface of the transfer case, and a belt-shaped member made of a good conductive material is arranged in the lower portion of the lower portion of the transfer case along the longitudinal direction thereof in a closed transfer passage so as to be opposed to the lower case. is there.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a magnetic levitation transfer device according to the present invention will be described below in detail with reference to the drawings. FIG.
As shown in FIG. 2 and FIG. 2, respectively, the apparatus of the present invention includes a transfer passage which is maintained in an ultra-vacuum or filled with a high-purity gas such as N2. Closed conveying passage 1 having a circular cross section
A transfer case (floating shuttle) 2 on which, for example, a wafer for semiconductor manufacturing is placed is arranged. The transfer case 2 includes a pair of plate-shaped transfer case upper base plates 3 and a transfer case lower base plate 4 having the same dimensions and a substantially rectangular planar contour. The base plates 3 and 4 are integrally connected via four vertical columns 5 symmetrically arranged in the longitudinal direction with respect to the vertical center plane X0-X0 and the vertical center plane XX of the transport pipe. Accordingly, the closed conveying passage 1 has a shape of a horizontal hollow box having a long dimension in the longitudinal direction, which is symmetric with respect to the vertical center plane XX of the closed conveying passage 1.

The upper surface of the upper base plate 3 of the transfer case 2 has a width, a certain length and a certain thickness symmetrical with respect to the vertical center plane XX of the closed transfer passage 1. A rectangular plate-shaped ferromagnetic material, for example, an iron piece 6 is fixed to each one close to the inner wall of the closed transfer passage 1 symmetrically with respect to the vertical center plane X0-X0 of the transfer case 2 in the longitudinal direction. Have been.

Further, on the upper surface of the transport case upper base plate 3,
A substantially rectangular position detection magnet 7 having a width, a certain length and a certain thickness symmetrical with respect to the vertical center plane XX of the closed transfer passage 1 is provided in the vertical direction of the transfer case 2 in the longitudinal direction. Symmetrically with respect to the center plane X0-X0, one by one is fixed to the outer end side of each iron piece 6 at a distance therefrom and close to the inner wall of the closed conveying passage 1.

Similarly, below the position detecting magnets 7 fixed to the upper surface of the transfer case upper base plate 4, a substantially rectangular plate-like magnet having a high magnetic flux density is provided on the lower surface of the transfer case lower base plate 4. For example, each of the permanent magnets 8 is fixed to the carrying case 2 symmetrically with respect to the vertical center plane X0-X0 in the longitudinal direction. A long plate-like plate having a certain width and a certain thickness,
The strip member 9 made of a good conductive material such as copper or aluminum
The center plane in the longitudinal direction is the vertical center plane X-
It is horizontally arranged so as to have a plane of symmetry in X, and is attached to the inner wall of the closed transfer passage 1 via insulating posts 10 arranged at intervals on its vertical center plane XX.

A drive truck 20 is disposed at the top outside the closed transfer passage 1. The drive truck 20 is
Symmetrical with respect to the vertical center plane XX of the closed conveying passage 1,
It has a substantially U-shaped cross section, has substantially the same length as the transport case 2, and has a rectangular planar contour, and its longitudinal direction is movable in the longitudinal direction of the closed transport path 1. Are arranged as follows. For this reason, this drive bogie 20
Near each longitudinal end of its lower surface, a pair of support members 21 having a substantially L-shaped cross section are provided on its lower surface from near its longitudinal edge. Secured at portion 211, its vertical leg portion 222
, A guide roller 22 is rotatably attached to each.

Further, a pair of guide rail mounts 23 having a substantially inverted L-shaped cross section spaced apart from the vertical center plane XX thereof are provided on the upper surface of the closed transfer passage 1. The vertical leg portions 231 are fixed at the lower edge thereof, and their horizontal leg portions 232 are fixed to the closed conveying passage 1 at their edge portions so as to be aligned in the same horizontal plane. On each of these horizontal leg portions 232, a pair of substantially L-shaped elongated guide rails 24 are provided, and their vertical leg portions 242 are provided at the vertical center of the closed conveying passage 1. In their horizontal leg portions 241, respectively, so as to be arranged symmetrically with respect to the plane XX,
It is fixed. A guide roller 22 rotatably mounted on the lower surface of the drive cart 20 is rotatably mounted on the top edge 240 of these vertical leg portions 242. The drive cart 20 is disposed parallel to the center axis YY of the conveying pipe in the vertical center plane XX at a position before and after intersecting with the vertical center plane XX of the closed conveying passage 1 on the lower surface thereof. Is connected to the moving wire W etc.
By driving the moving wire W by an appropriate driving mechanism, the moving wire W can be driven freely with respect to the closed conveyance path 1.

From the lower surface of the drive carriage 20, a pair of electromagnets (A) 30 and electromagnets (B) 31 are symmetrically arranged with respect to the vertical center plane XX of the closed conveyance path 1 and the conveyance case 2
Each of the electromagnets (A) and (B) 30 and 31 is attached to the closed transfer passage 1 in a manner corresponding to the position of each iron piece 7 attached to the upper surface of the upper base plate 3. And a pair of electromagnets (A) 301, 302 and electromagnets (B) 311, 312 arranged at intervals in the direction of the center line Y-Y of FIG. The electromagnets (A) 301, 312 and the electromagnets (B) are respectively arranged close to the upper surface of the closed conveyance passage 1, and thus each pair of the electromagnets (A), (B) 30, 31 is used. ) 311, 312
Are respectively opposed to the corresponding iron pieces 7 arranged on the upper surface of the upper base plate 3 of the transfer case 2 with the wall of the transfer case 2 interposed therebetween.

Further, the electromagnets (A) are provided on the lower surface of the drive carriage 20 within the vertical center plane XX of the closed conveyance path 1.
Positions of the position detecting magnets 7 fixed to the upper surface of the upper base plate 3 of the transport case 2 symmetrically with respect to the vertical center plane X0-X0 of the transport case 2 outside the electromagnet 30 and the electromagnet (B) 31. In correspondence with the above, a columnar magnetic sensor 35 for position detection is attached to each other, and its lower surface is attached to the upper surface of the upper base plate 3 of the transfer case 2 via the wall of the sealed transfer passage 1. The position-detecting magnets 7 oppose each other, and the position-detecting magnetic sensors 35 and the position-detecting magnets 7 form position detecting mechanisms (A) and (B), respectively. It has become.

The device of the present invention has the above-described configuration. Next, the operation of the device will be described. Sealed transport passage 1,
The transport case 2, the drive cart 20 and the like are in the state shown in FIGS. 1 and 2, and from this state, the transport case 2 is moved along the closed transport path 1 at a constant speed in the direction of arrow Z below the floating state. It shall move in the horizontal direction. First, in this state, when the electromagnet (A) 30 and the electromagnet (B) 31 are energized, as shown in FIG. 3, the iron pieces 6 attached to the upper surface of the upper base plate 3 of the transfer case 2 are moved by the magnetic force. Is sucked through the wall of the closed transfer passage 1, so that the transfer case 2 is floated in the closed transfer passage 1, so that the drive carriage 20 is driven via the moving wire W or the like. Thus, the transfer case 2 can be moved while floating in the closed transfer path 1.

When the transport case 2 is lifted and moved in this way, the permanent magnet 8 fixed to the lower surface of the lower base plate 4 is moved below the center line Y into the closed transport path 1. An eddy current is generated in the belt-like member 9 made of a good conductive material, such as a copper plate or an aluminum plate, which is installed in parallel with -Y. The movement of the transport case 2 is smoothly performed.

As described above, when the transfer case 2 floats inside the closed transfer passage 1, the floating level is determined by the position detecting magnet fixed to the upper surface of the upper base plate 3 of the transfer case 2. 7 and a magnet sensor 35 attached downward from the lower surface of the drive cart 20 to detect the position by the capacitance-based position detection mechanisms (A) and (B), and the transport case 2 holds this detection position by the control circuit. As it moves, it is moved in the longitudinal direction of the closed conveyance path 1.

In the above embodiment, the closed transfer passage 1 is assumed to be linear, but the electromagnet unit outside the transfer case 2 is supported by a universal bearing, so that the transfer case 2 Can be freely rotated and moved straight in the closed transfer passage 1. Further, as the position detecting magnet 7 and the high magnetic flux density magnet 8,
A metal magnet or a canned (enclosed) magnet is used to withstand baking (about 250 ° C.) for ultra-high vacuum. Further, in the above embodiment, the drive truck 20 is driven by pulling with a wire W or the like, but instead, the drive truck 20 is driven by a linear pulse motor as in the prior invention. It is clear that we can do that.

[0027]

Since the present invention has the above-described structure and operation, it is possible to exhibit the effects of the prior invention as it is, and in addition to this, it is also possible to use an ultra-high vacuum or a high-purity gas. The transfer case can be magnetically levitated and moved without contact in a closed transfer path under a special environment, and the position of the transfer case with respect to the closed transfer path can be accurately detected and the stop position can be set. Can be precisely controlled, and it is possible to realize dust-free transfer in the case of semiconductor manufacturing, etc., and despite the compact configuration, smooth lifting, smooth movement and desired movement of the transfer case. It is also possible to exert an effect that an accurate stop at the stop position and a smooth descent are possible. For example, according to one experiment, it has been confirmed that the positioning accuracy of the transfer case can be as high as ± 0.2 mm.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along line II of FIG. 2 showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of one embodiment of the present invention shown in FIG.

FIG. 3 is a block diagram showing a control circuit for the embodiment shown in FIGS. 1 and 2;

FIG. 4 is a cross-sectional view showing a “floating-type article transfer device in vacuum” according to the above invention.

FIG. 5 is a longitudinal sectional view thereof.

FIG. 6 is a diagram showing a transfer operation pattern of the transfer case.

[Explanation of symbols]

 Reference Signs List 1 density transfer passage 2 transfer case (floating shuttle) 3 transfer case upper base plate 4 transfer case lower base plate 5 support 6 ferromagnetic material (iron piece) 7 position detecting magnet 8 strong magnet (high magnetic flux density permanent magnet) 9 good Conductive material belt-shaped member 10 Insulating column 20 Drive carriage 21 L-shaped support member 22 Guide roller 23 Guide rail support gantry 24 Guide rail 30 Electromagnet (A) 31 Electromagnet (B) 35 Magnetic sensor for position detection

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuzo Hayashi 4-11-7 Ginza, Chuo-ku, Tokyo Second Uehara Building Inside Irie Koken Co., Ltd. (72) Inventor Noriyuki Irie 4-11 Ginza, Chuo-ku, Tokyo -7 Second Uehara Building Irie Koken Co., Ltd. (56) References JP-A-2-152820 (JP, A) JP-A-2-188104 (JP, A) JP-A-3-66920 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) B65G 54/00-54/02 B65G 49/07 H01L 21/68 B60L 13/02-13/10

Claims (2)

(57) [Claims] 1. A closed transfer passage (1) which is held in a high vacuum or is filled with a high-purity gas, and a closed transfer passage (1) which is disposed at the top of the closed transfer passage (1) and which is located outside the closed transfer passage (1). A drive truck (20) that can be driven along the
(1) and a transfer case (2) movably disposed in the transfer case (2), a ferromagnetic material is attached to the top of the transfer case (2), and this ferromagnetic material is 20)
The transfer case (2) is attracted by an electromagnet attached to the lower surface of the transfer case (2), and the transfer case (2) is floated and moved in the closed transfer path. A magnet for position detection (7) is attached to the top, and a magnetic sensor for position detection (35) is attached to the drive bogie (20), and the position detection magnet and the closed transfer passage
Attached so as to face the wall of (1), and attached a high magnetic flux density magnet to the lower surface of the transfer case (2),
Further, a band-shaped member (9) made of a good conductive material is arranged along the longitudinal direction in the closed transport passage (1) at a lower portion thereof so as to oppose with an interval therefrom. Magnetic levitation transfer device. 2. The magnetic levitation transfer device according to claim 1, wherein the high magnetic flux density magnet attached to the lower surface of the transfer case is a permanent magnet.