JPS63139632A - Vacuum suction device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to vacuum suction technology, in particular to technology for repeatedly suctioning and holding thin plate-like objects, for example, in the process of manufacturing semiconductor devices. Concerning effective techniques that can be used to

[Conventional technology]

2. Description of the Related Art In the manufacturing process of semiconductor devices, some systems for handling wafers are configured to alternately receive and transfer wafers between an air conveyor and a vacuum suction device.

As a vacuum suction device used in such systems,
A suction head having a suction surface, a suction port provided on the suction surface, a suction path that supplies negative pressure to the suction port, a first on-off valve interposed in the middle of the suction path, and a suction port provided in the suction path. and a fluid supply path connected via a second on-off valve,
When releasing the suction and holding of the wafer by the suction port, the first on-off valve is closed to stop the supply of negative pressure, and then the second on-off valve is opened to supply fluid to the suction port to release the suction. There are some that are configured in

Incidentally, an example of vacuum adsorption technology described in Japanese Patent Application Laid-open No. 5
No. 7-128939.

[Problem that the invention seeks to solve]

However, in such a vacuum suction device, the release of vacuum suction holding is performed by switching between negative pressure and positive pressure using the first and second on-off valves, so the wafer may not touch the suction head when positive pressure is supplied. A floating phenomenon occurs, and as a result,
The inventor of the present invention has revealed that there is a problem in that the delivery of wafers to the air conveyor becomes uncertain.

An object of the present invention is to provide a vacuum suction device that can prevent an adsorbed object from moving when suction holding is released.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

An overview of typical inventions disclosed in this application is as follows.

That is, an inner opening and an outer opening surrounding the inner opening are provided on the suction surface, and each ventilation passage is connected to each opening, and a directional control valve is provided to each of these ventilation passages to switch the supply of negative pressure and positive pressure. It was established.

[Effect]

According to the above-described means, by appropriately operating the bidirectional control valve, it is possible to supply positive pressure to the inner opening while maintaining negative pressure supply to the outer opening when vacuum suction is released, so that it is possible to supply positive pressure to the inner opening. An air layer can be locally and temporarily confined in relation to the adsorption surface. This air layer momentarily warps the adsorbed object, but when positive pressure is supplied to the outer opening, it floats vertically from the adsorption surface due to its own restoring force.

In other words, the object to be attracted does not move laterally, but is lifted vertically from the attraction surface and is released from attraction.

〔Example〕

Fig. 1 is a schematic plan view showing a vacuum adsorption device which is an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is for explaining its operation. The time chart diagrams, FIGS. 4 and 5 are also longitudinal sectional views.

In this embodiment, this vacuum suction device is equipped with a suction head 2, and this head 2 is configured to be raised and lowered by a drive device (not shown). The suction pad 2 is formed into a substantially disk shape, and its upper surface forms a suction surface 3 with a smaller diameter than the outer diameter of the wafer 1 as the object to be held. The suction surface 3 has a center hole 4, an intermediate hole 5, and a peripheral hole 6, each of which substantially constitutes an opening, each having a circular small hole shape.
On the center line of the suction surface 3, a plurality of intermediate holes 5 are arranged at approximately equal intervals in the circumferential direction so as to surround the center hole 4 on a concentric circle of the suction surface 3, and a plurality of peripheral holes 6 are arranged on the peripheral part of the suction surface 3. They are arranged at approximately equal intervals in the circumferential direction so as to concentrically surround the intermediate hole 5.

There are an IJ1 ventilation path 7 and a second ventilation path 8 inside the suction head 2.
are arranged and opened so that they are fluidly independent (do not communicate) with each other, and the first ventilation passage 7 is connected to the intermediate hole 5, and the second
The ventilation path 8 is configured to communicate with the center hole 4 and the peripheral hole 6, respectively.

As a result, the peripheral hole 6 group substantially constitutes an outer opening surrounding the intermediate hole 5 group as an inner opening. Both pipes 9 and 1O are connected to a negative pressure source 11 such as a vacuum pump and a positive pressure source 12 such as an air tank. There is.

First and second solenoid valves 13.14 as directional control valves are interposed in the middle of both piping 9.10, and both solenoid valves 13.14 supply negative pressure 1itt and positive pressure source 12 to the piping. The solenoids 15 and 16 of the two solenoid valves 13 and 14 are connected to a controller 17 consisting of a computer, a timer, etc.
By operating 3.14 as appropriate, it is configured to realize the effects described below.

In this embodiment, as shown in FIG. 1, the suction head 2 is disposed near the end of the air conveyor 20, and is configured to receive and pass the wafer l between it and the air conveyor 20. It has become. This air conveyor 20 has a structure in which both side guides 21 do not reach the outside of the suction hood 2. In addition, in order to transfer the wafer from the suction head 2 to the air conveyor 20, the suction hood 2 has a plurality of feeding outlets 18 that are connected to the air conveyor 20.
They are arranged in two rows parallel to the center line of the air conveyor 20 (Ill), and are opened so that air can be blown upward at an angle to the air conveyor 20 (Ill).

Next, the effect will be explained.

When the wafer 1 as an object to be attracted is sent from the air conveyor 20 onto the attraction surface 3 of the attraction head 2 and mechanically positioned by a stopper (not shown) or the like, a As shown in FIG. 3, the first and second solenoid valves 13.14 are connected to the piping 9.
10 to the negative pressure source 11, respectively.

As a result, negative pressure is supplied to all of the center hole 4, intermediate hole 5, and peripheral hole 6 via the first and second ventilation passages 9.10, so that the wafer 1 is vacuum-suctioned entirely on the suction surface 3. and is held by the suction head 2.

In this vacuum suction holding state, the suction head 2 is raised, and the wafer 1 is subjected to a desired operation.

Thereafter, when the vacuum holding on the wafer l is released, as shown in FIG. It can be switched overwhelmingly. Subsequently, after a certain amount of time (for example, about 0.5 seconds) has passed, the second solenoid valve 14 is also switched to forward pressure, and when air is blown out from the feeding outlet 18, the wafer l moves laterally. The air conveyor 2G's guides 21.
It is sent straight and properly between 21 and 21.

By the way, if positive pressure is supplied to all the holes at the same time when vacuum suction holding is released, the wafer 1 will be slightly tilted with respect to the suction surface 3 as shown in FIG. As shown by the imaginary line in , an accident occurs in which the wafer l shifts laterally and collides with one guide 21 without being sent between the guides 21 and 21 of the air conveyor 20.

This is thought to occur because the wafer 1 is tilted due to variations in the magnitude of the positive pressure in each hole.

However, in this embodiment, when the vacuum suction holding is released, there is a time difference in switching from negative pressure to positive pressure for the center hole 4, peripheral hole 6, and intermediate hole 5, so that the wafer l is vertically It floats up and is properly sent to the air conveyor 20.

That is, first, when the first solenoid valve 13 is switched to positive overflow while the second solenoid valve 14 remains connected to negative overflow,
Negative pressure is supplied to the center hole 4 and peripheral hole 6 through the first ventilation path 9O, and positive pressure is supplied to the intermediate hole 5 through the first ventilation path 9, as shown in FIG. So, wafer 1
is elastically deformed extremely minutely so that a local air layer 19 is formed between it and the suction surface 3. At this time, the group of peripheral holes 6 serving as the outer openings attracts the peripheral portion of the wafer l, thereby sealing the air layer 19 caused by the group of intermediate holes 5 serving as the inner openings. However, the wafer 1 instantaneously restores its original flat shape due to its own elasticity.

During this restoration, when the second solenoid valve 14 is switched to positive pressure, the wafer 1 floats vertically without moving laterally, regardless of variations in the positive pressure distribution, and the wafer 1 floats vertically through the feeding outlet 18.
The air is properly fed into the air conveyor 20 according to the air blown from the air.

According to the embodiment described above, the following effects can be obtained.

(1) An inner opening and an outer opening surrounding the inner opening are provided on the suction surface, and each ventilation passage is connected to both openings, and a directional control valve is installed in each of these ventilation passages to switch the supply of negative pressure and positive pressure. By intervening respectively,
By appropriately operating the two-way control valve, it is possible to supply positive pressure to the inner opening while maintaining negative pressure to the outer opening when vacuum suction is released, thereby locally and temporarily making the target object elastic. can be transformed, so that
By utilizing the restoration after deformation, the object to be attracted can be made to float perpendicularly to the suction surface, and proper release of vacuum suction can be achieved.

(2) By floating the object perpendicular to the suction surface when vacuum suction is released, the object can be properly fed into the air conveyor, etc. without causing lateral displacement, so both sides of the air conveyor Even in situations where the guide cannot be extended to the opposite part of the vacuum suction device, the article after suction is released is properly fed between the guides on both sides of the air conveyor without causing an irI accident or falling accident. be able to.

Incidentally, a situation in which it is not possible to extend the guide of the air conveyor to the vacuum suction device is the handling situation in which the wafer is transferred by the air conveyor to the vacuum suction device installed on the exposure stage in a contact exposure system. system may be used. That is, in this case,
Since other equipment of the exposure stage is installed around the vacuum suction device, the guide of the air conveyor cannot be extended to the vacuum suction device.

(■ By configuring the directional control valve to be automatically operated by a controller consisting of a computer, timer, etc., the vacuum suction and release operations of the vacuum suction device can be fully automated, making it possible to unmanned or save labor. can be promoted.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the Examples and can be modified in various ways without departing from the gist of the invention. Not even.

For example, the configuration is not limited to supplying positive pressure to the 5 groups of intermediate holes while maintaining the negative pressure supply to the 6 groups of peripheral holes when vacuum suction is released; Mama,
It may be configured to supply positive pressure to the center hole 4. In this case, the intermediate hole 5 group becomes an outer opening surrounding the center hole 4 as an inner opening.

The inner opening and the outer opening are not limited to being formed by a plurality of small holes, but may be formed by an annular groove or the like.

The switching time difference from negative pressure supply to positive pressure supply to the outer opening when vacuum suction is released, the effective opening IT of the outer opening and inner opening, etc. are determined by the pumping speed of the negative pressure source, the pressure of the positive pressure source, etc., and the adsorbed target. It is desirable to appropriately set the optimal value for each case by experiment or empirical analysis method using computer shemiresis, depending on the relationship between the degree of elastic deformation of the object and its restoring force.

Further, it is desirable that the shapes, structures, etc. of the suction head, suction surface, openings, ventilation passages, etc. be modified as desired.

In the above explanation, the invention made by the present inventor was mainly applied to a vacuum suction device for wafers, which is the background field of application of the invention, but it is not limited thereto, and is applicable to other substrates, plate materials, etc. It can be used in general vacuum suction devices that vacuum suction solid objects such as small pieces and rectangular parallelepipeds.

(Effects of the Invention) The effects obtained by typical inventions disclosed in this application will be briefly described as follows.

An inner opening and an outer opening surrounding the inner opening are provided on the suction surface, and each ventilation passage is connected to both openings, and a directional control valve for switching the supply of negative pressure and positive pressure is interposed in each of these ventilation passages. By operating the two-way control valve appropriately, it is possible to supply positive pressure to the inner opening while maintaining negative pressure to the outer opening when vacuum suction is released, which allows the target object to be locally and It can be temporarily elastically deformed, and as a result, the object to be attracted can be made to float perpendicularly to the suction surface by using the restoration after deformation, and proper release of vacuum suction can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing a vacuum adsorption device which is an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view taken along line 1'' in Fig. 1, and Fig. 3 is a diagram for explaining its operation. The time chart, FIG. 4, and FIG. 5 are also longitudinal sectional views. 1... Wafer (object to be attracted), 2... Suction head, 3
... Adsorption surface, 4... Center hole, 5... Middle hole (inner opening), 6... Peripheral hole (outer opening), 7... First ventilation path, 8... Second Ventilation path, 9.10...Piping, 11
... Negative pressure source, 12... Positive pressure source, 13.14... Solenoid valve (directional control valve), 15.16- - Solenoid,
17... Controller, 18... Feeding outlet, 1
9...Air layer, 20...Air conveyor, 2I...
Side guide. 1st Figure 4-f To the heart, y- (18 cows? Booku (I te 1 I) P゛1 listen)
c-saw, 6th (yyf+1 F/I o )th
2 Fig. 3 Fig. 1 --- Extrusion Fig. 4 Fig. 5

Claims (1)

[Claims] 1. An inner opening disposed on the inner part of the suction surface, an outer opening disposed on the suction surface so as to surround the inner opening, and an inner opening and an outer opening connected to each other. It is equipped with each ventilation path and each directional control valve that is installed in each of these ventilation paths and configured to switch the supply of negative pressure and positive pressure. 1. A vacuum adsorption device characterized in that it is configured to form a local layer under an object to be adsorbed by supplying positive pressure to an inner opening while maintaining a negative pressure supply. 2. The vacuum suction device according to claim 1, wherein the inner opening and the outer opening are each composed of a plurality of small holes, and are arranged in an annular shape that is concentric with each other. 3. The vacuum suction device according to claim 1, wherein the outer opening is composed of a plurality of small holes and is arranged on an annular line surrounding the inner opening.