JPH01157546A - Wafer transfer apparatus - Google Patents

Abstract

PURPOSE:To transfer a wafer one by one stably by using a simple apparatus without producing a dust particle and by using a clean room with a high degree of cleanliness by a method wherein, while a vehicle is being floated from a transfer route by using a magnetic fluid, the vehicle is moved along the transfer route and the wafer placed on the vehicle is transferred one by one. CONSTITUTION:While a vehicle is being floated on a travelling guide 12 by using a permanent magnet and a magnetic fluid, it is pulled by using a rope and is moved. A magnetic fluid 6 is attracted to the circumference of permanent magnets 42, 52 due to an influence of a magnetic field generated by the respective permanent magnets 42, 52 installed at a lower-end face of vehicles 4, 5; a buoyant force is generated magnetically; the permanent magnets 42, 52 are floated. Accordingly, the vehicles where the permanent magnets 42, 52 have been installed at the lower part are floated. Because the vehicles are moved by using ropes 7, 8 and the magnetic fluid 6 is moved by a driving force to pull the ropes together with the permanent magnets 42, 52, the vehicles are floated and moved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for transporting wafers one by one.

[Conventional technology and its problems]

As a device for conveying thin plate-shaped articles such as wafers in a clean room, there are two methods: (1) a method in which the wafer is levitated by air pressure and is further conveyed by jet air pressure, and (2) a method in which the wafer is placed on a conveyor and conveyed. be.

However, the former method requires a device that constantly supplies air pressure, and dust may be generated from the guide or stop device for the wafer transport path, which poses problems when used in a clean room.

Further, in the latter method, when the wafer is conveyed on the belt, dust generated from the belt adheres to the back surface of the wafer, which is one of the causes of poor yield in the wafer manufacturing process.

Furthermore, in the past, wafers were not moved one by one between processes in each wafer manufacturing apparatus, and several wafers were often stored in a wafer cassette and transported to Re.

However, as the diameter of the wafer becomes larger and the production becomes more diverse,
With the trend toward small-volume production, there has been a demand for equipment that can transport wafers one by one between processes in manufacturing equipment.

In addition, as wafer processing becomes finer, -
Conveying equipment with high layer cleanliness has become necessary.

The present invention is a simple device that does not generate dust, can be used even in highly clean rooms, and can handle 1 wafer.
The purpose is to transport sheets stably one by one.

[Means for solving problems]

The present invention includes a vehicle having a slit in the surface on which the wafer is placed so that the wafers can be received and delivered one by one to a transfer device, a permanent magnet provided on the bottom surface of the vehicle, and a permanent magnet provided on the bottom surface of the vehicle. The vehicle is floated from the transport path by a magnetic fluid interposed between it and the transport path, and the vehicle is moved along the transport path by a linear motor or rope trolley type drive device, and the wafers placed on the vehicle are transported one by one. This is a wafer transport device.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The wafer conveyance apparatus of the present invention will be explained below based on the illustrated embodiments.

Fig. 1 is an overall plan view showing a first embodiment of a wafer transport device according to the present invention, Fig. 2 is a front view thereof, Fig. 3 is a vertical side view, and Fig. 4 shows a rope trolley tensioning structure. FIG. 5 is an explanatory diagram showing the relationship between the vehicle and the travel guide.

In the figure, reference numeral 1 denotes a conveyance path made of a non-magnetic material, and this conveyance path consists of a traveling guide 12 disposed on a base 11 as shown in FIGS. 1 to 3. One or more grooves 13.13 are formed on the top surface of the rail over the entire length of the rail and are open to the top surface. Further, one or more sensors 14 are disposed on the side of the guide 12 to detect the position of the vehicle, which will be described later, in order to stop the vehicle at a predetermined position on the transport path 1.

At both ends of the conveyance path 1, there are mounted drums 31 and 32 which are rotatably driven by a power source 2 such as a motor.
2 can be selectively driven into forward rotation and reverse rotation via the power source 2 or the transmission.

Two vehicles 4.5 are placed on the conveyance path 1.

The vehicles 4 and 5 have the same shape, and have a slit in the surface on which the wafers are placed so that - wafers W can be easily transferred using a fork of an external transfer device, and a traveling guide of the vehicle. Magnet mounting base 4 on the bottom surface of 12
1.51 is provided, and a permanent magnet 42.52 is fixed to the lower end surface of this magnet mount 41.51.

6 is a magnetic fluid, which is interposed between the lower end surface of the magnet mount 41.51 and the groove 13 so that the magnetic field of the permanent magnet 42.52 acts thereon. The permanent magnets 42, 52 provided at the bottom of the vehicle may be a single magnetic bar that is approximately equal in length to the direction of travel of the vehicle, but
As shown in FIG. 5, a plurality of permanent magnets are provided with the front and rear ends in the traveling direction of the vehicle 4.5 curved upward, and the lower end surfaces of these permanent magnets are curved, and when the vehicle moves forward or backward,
The magnetic fluid provided in the concave groove is always interposed between the permanent magnet and the bottom of the conveyance path concave groove. That is, the magnetic fluid is broken at the corners of the permanent magnet to prevent it from tangentially colliding with the groove.

This magnetic fluid 6 is disposed in the groove of the traveling guide 12 so that the magnetic field of the permanent magnets 42, 52 acts on it, and the magnetic fluid 6 is used to coat the surface of magnetic fine particles such as ferrite with long-chain unsaturated fatty acids. This is a well-known colloidal solution coated with a surfactant and dispersed in the solution using a surfactant.

Vehicles 4 and 5 are moved by drums 31 and 32 and vehicle 4.
, 5 is wound up and unwound onto the drum. One of the lobes 7 is wrapped around the drum 31 once or multiple times, and its one end is fastened to a cable fitting 43 protruding from the vehicle 4, and the other end is located outside of the entire transport process of the vehicle 4. and the sheave 9 facing the drum 31
1, and then fastened to the lobe attachment 44 of the vehicle 4. Therefore, the lobe 7 is stretched between the drum 31 and the sheave 91, and both ends are fixed to the same vehicle 4.
By rotating it, it is caused to reciprocate along the travel rail via the lobe 7.

Similarly, the other lobe 8 is wound one or more times around the drum 32, and then one end of the lobe 8 is wrapped around the lobe fitting 53 of the vehicle 5, and the other end is hooked onto the sheave 92 facing the drum 32, and then the rope is attached to the vehicle 5. It is fastened to the fitting 54. In this way, the two vehicles 4 and 5 are placed opposite each other on the concave groove 13 of the same running rail 12 via the permanent magnets 42 and 52 and the magnetic fluid 6 so as to be able to travel freely. The suspended rope 7.8 is selectively made to run by rotating the drum 31.32, and one vehicle 4 is moved to A in FIG.
The other vehicle 5 arbitrarily travels from the point to the point E, and from the point F to the point B. At this time, both vehicles 4.5 are controlled so as not to come into contact with each other. The traveling distance and stopping positions of the vehicle are determined in the work process, and the distance between each point and the number of stopping positions are shown in the illustrated embodiment as an example, and can be arbitrarily determined. The vehicle is stopped at a fixed position by detecting the vehicle's position using a sensor placed on the side of the rail.

Further, the conveyance path 1 is partially or entirely covered with a cover 15 provided with a slit so as not to disturb the movement of the vehicle so as not to scatter fine dust generated in the clean room when the vehicle runs.

The vehicle is floated on the travel guide 12 using a permanent magnet and magnetic fluid, and is driven by a rope.

That is, the magnetic fluid 6 is magnetically an aggregate of molecules having a permanent magnetic moment and has superparamagnetic properties. Due to the influence of the magnetic field generated by the respective permanent magnets 42.52 provided on the lower end surfaces of the vehicles 4, 5, the magnetic fluid 6 is attracted around the permanent magnets 42.52, magnetically buoyant force is generated, and the permanent magnets 42 , 52 will be levitated. Therefore, the vehicle with the permanent magnets 42, 52 provided at the bottom will float.

Then, the magnetic fluid 6 moves together with the permanent magnets 42.52 due to the driving force of the lobe pulling by the vehicle by the rope 7.8, so that the vehicle is levitated and moves.

At this time, in this embodiment, the vehicle is supported at two locations and driven by a rope, so that the vehicle can always be moved in a stable state. Further, by providing the cover 15 on the conveyance path 1, it is possible to prevent the magnetic fluid from flowing out from the inside of the conveyance path 1 and further reduce the amount of evaporation of the solvent of the magnetic fluid.

FIG. 6 is a longitudinal cross-sectional side view showing a second embodiment of the wafer transport device of the present invention. This embodiment is a diagram showing an example in which the vehicle of the wafer transport apparatus of the present invention is driven by a linear motor to move the transport path. In the previous embodiment, a case was shown in which a rope was used to move the vehicle along the conveyance path, but in this embodiment, a linear motor is used instead of the rope to move the vehicle along the conveyance path. Not shown.

Components that are the same as those in FIGS. 1 to 5 are designated by the same reference numerals, and their explanations will be omitted.

A stator 61 of a linear motor is placed on the upper surface of the traveling guide 12 at a predetermined interval in the traveling direction of the vehicle 4.5. In addition, the bottom surface 71 of the vehicle 4.5 facing the linear motor stator 61 is made of a conductive material such as aluminum or copper plate so as to act as a reaction plate of the linear motor, and is connected to the stator 61 through a gap. They face each other and form a linear motor.

With this configuration, the vehicle is levitated on the traveling guide by the action of the permanent magnet and the magnetic fluid as described above, and is driven by the linear motor.

In each of the above embodiments, the number of grooves is two, but the number of grooves is not limited to this.
Of course, you can do more than just a book.

In addition, the number of vehicles placed on the conveyance path is the same as 2 in this embodiment.
The number of units is not limited, and it is of course possible to select one or more units as appropriate.

〔Effect of the invention〕

In the present invention, the surface of the vehicle on which the wafer is placed is shaped so that a single wafer can be placed stably, and the vehicle is levitated by the action of a magnetic fluid and a permanent magnet, and the vehicle is levitated by the action of a magnetic fluid and a permanent magnet. Since the transport path is driven by a drive, the structure is simple and dust generation is suppressed.
Since the material of the vehicle can be selected arbitrarily, it is possible to prevent dust from adhering to the wafers, and since there are no sources of vibration such as wheels or gears, there is no vibration to the wafers, and the wafers can be smoothly processed one by one. It has the advantage of being extremely compact in structure and can be transported in a highly clean manner.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the entire transport device of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a vertical side view, Fig. 4 is an explanatory view showing a rope tensioning system, and Fig. 5 is a diagram showing a vehicle and a vehicle. FIG. 3 is an explanatory diagram showing the relationship with a travel guide. Figure 6 shows the second part of the conveying device of the present invention.
FIG. 3 shows a longitudinal side view of the embodiment. 1 is a transport path, 12 is a travel guide, 13 is a groove, 15 is a cover, 2 is a power source, 31.32 is a drum, 4 and 5 are vehicles, 42.52 is a permanent magnet, 6 is a magnetic fluid, 61 is the linear motor stator, 7 and 8 are the lobes, and 91° and 92 are the sheets.

Claims (1)

[Claims] (1) A transport path for transporting a vehicle that places wafers one by one, a vehicle with a slit on the surface on which the wafer is placed so that the wafers can be delivered one by one to a transfer device, and a slit on the bottom surface of the vehicle. A magnetic fluid interposed between the permanent magnet provided on the underside of the vehicle and a conveyance path, and a linear motor or rope trolley type drive device for moving the vehicle along the conveyance path. A wafer conveying device characterized in that a vehicle is moved along a conveyance path while being levitated from the conveyance path by a magnetic fluid, and wafers placed on the vehicle are conveyed one by one.