JP2013138056A - Suction pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suction pad capable of sucking an object to be sucked such as a semiconductor wafer without damaging, with no use of a complicated facility.SOLUTION: The suction pad 1 includes a porous pad part 7 containing an upper surface 7a and a lower surface 7b on which a semiconductor wafer 5 is placed, and a holding part 9 for holding the pad part 7. The pad part 7 includes a first portion L made from a first porous material having a predetermined gas permeability along the direction from the upper surface 7a of the pad part 7 to the lower surface 7b, and a second portion H which is made from a second porous material having the gas permeability along the direction from the upper surface 7a of the pad part 7 to the lower surface 7b being higher than that of the first porous material. The holding part 9 directly connects the air hole of the first portion L forming the pad part 7 and the air hole of the second portion H to a vacuum source through the lower surface side of the pad part 7.

Description

  The present invention relates to a suction disk, and more particularly, to a suction disk that is configured to be connected to a vacuum source and that adsorbs a plate-like object by operating the vacuum source.

  2. Description of the Related Art Conventionally, in equipment for transporting a semiconductor wafer from one processing step to the next, a suction disk that sucks and fixes a semiconductor wafer to be transported has been used. Such a suction disk has a stage composed of a porous body in which pores are uniformly distributed. When adsorbing and fixing a semiconductor wafer on the stage, the semiconductor wafer is first brought into contact with the flat upper surface of the stage, and then the holes in the porous body are evacuated by a vacuum pump, whereby the semiconductor wafer is placed on the flat upper surface of the stage. Is adsorbed to the suction disk and fixed.

  In recent years, as semiconductor wafers have become larger and thinner, it has been desired that the semiconductor wafers that have been made larger and thinner can be properly sucked and fixed even in the suction disk as described above. Generally, when a semiconductor wafer is increased in size and thickness, the semiconductor wafer is easily bent, and there has been a possibility that the semiconductor wafer may be damaged when a suction disk that has been used conventionally is used.

  That is, when adsorbing and fixing a large-sized / thinned semiconductor wafer using a general adsorber, the pores of the porous body are uniformly distributed on the adsorber, so that it is connected to the adsorber. When the vacuum pump is operated, the adsorption is started simultaneously in all the holes opened in the contact surface between the adsorption disk and the porous body.

Here, since it is difficult to place a particularly large semiconductor wafer on the suction plate without bending, the semiconductor wafer is placed on the suction plate in a bent state. . When the semiconductor wafer is placed on the suction plate in a bent state, a portion in contact with the suction plate and a portion not in contact with the semiconductor wafer are formed.
If the vacuum pump is operated in this state and air suction is started simultaneously in all the holes opened on the contact surface between the suction disk and the porous body, the portion where the semiconductor wafer and the suction disk are in contact with each other. Adsorption begins. As a result, an external force that deforms the bent semiconductor wafer is generated due to the difference in suction speed, and the internal stress of the semiconductor wafer is significantly biased. As a result, the semiconductor wafer is damaged.

  As a technique for preventing such damage of the semiconductor wafer, an apparatus described in Patent Document 1 is known.

JP-A-7-58191

  The apparatus of Patent Document 1 includes an electromagnetic valve disposed in each of a stage on which a semiconductor wafer is placed, a plurality of through holes formed in the stage, and a flow path connecting each through hole and the vacuum pump. And a control unit for controlling the solenoid valve. In the apparatus of Patent Document 1, the control unit independently controls each electromagnetic valve according to the warp of the semiconductor wafer, and independently controls the suction speed acting on the semiconductor wafer from the through hole for each through hole. This prevents the semiconductor wafer from being damaged when the semiconductor wafer is sucked and fixed.

  However, the above-described apparatus of Patent Document 1 has a problem in that a complicated facility is required to provide an electromagnetic valve for each of the plurality of through holes formed in the stage and to control each electromagnetic valve individually. It was. This problem becomes particularly noticeable when the semiconductor wafer is enlarged.

  The same problem has arisen when handling a large thin plate such as a glass panel for FPD (Flat Panel Display).

  Therefore, the present invention has been made to solve the above-described problems, and can adsorb an object to be adsorbed such as a semiconductor wafer or a glass panel for FPD without damaging it without using complicated equipment. An object of the present invention is to provide a suction cup that can be used.

  In order to solve the above-described problems, the present invention is configured to be connected to a vacuum source, and is an adsorption disk for adsorbing a plate-shaped object to be adsorbed by operating the vacuum source. A porous pad portion having an upper surface and a lower surface on which the adsorbate is placed, and a holding portion for holding the pad portion. The pad portion transmits a predetermined gas from the upper surface to the lower surface of the pad portion. A first portion formed of a first porous material having an amount, and a second porous material having a gas permeation amount in the direction from the upper surface to the lower surface of the pad portion greater than that of the first porous material. The holding portion is a flow for directly connecting the pores of the first porous material and the second porous material forming the pad portion to the vacuum source from the lower surface side of the pad portion. It is characterized by having a road.

  According to the present invention configured as described above, the gas permeation amount is different between the pad portion on which the object to be adsorbed is placed in the portion corresponding to the first portion and the second portion. Then, when an object to be adsorbed is placed on the upper surface of such a suction plate and connected to a vacuum source to start evacuation in the pores of the pad portion from the lower surface side, the first porous material having a relatively small gas permeation amount The adsorption speed of the second portion formed of the second porous material having a relatively large gas permeation amount is faster than that of the formed first portion. Therefore, when evacuation is started, first, a part of the object to be adsorbed that is in contact with the portion corresponding to the second portion of the upper surface of the pad portion is adsorbed to the pad portion. And a part of the to-be-adsorbed object which contact | connects the part corresponding to a 1st part among the upper surfaces of a pad part late | sucking to this is adsorbed by a pad part. In this way, by forming the pad portion with two porous materials having different gas permeation amounts, the adsorption rate between the portion corresponding to the first portion and the portion corresponding to the second portion of the upper surface of the pad portion. Difference can be generated. As a result, the object to be adsorbed can be adsorbed and fixed to the pad portion in two stages, so that it is possible to prevent the object to be adsorbed from being excessively bent, thereby causing excessive stress concentration inside the object to be adsorbed. It can be prevented from occurring.

  Further, according to the present invention configured as described above, the pores of the first porous material forming the first portion having a relatively low suction speed and the second porous forming the second portion having a relatively high suction speed. The pores of the material can be directly connected to the vacuum source via the flow path. Thereby, it is possible to generate different adsorption speeds in the portion corresponding to the first portion and the portion corresponding to the second portion of the upper surface of the pad portion simply by operating the vacuum source. In this case, since it is not necessary to use a control valve or the like, the object to be adsorbed can be prevented from being damaged with a simple structure.

According to another preferred embodiment of the invention,
The pad portion has a rectangular shape, and the second portion is positioned at a corner of the pad portion.
According to such a configuration, the rectangular thin plate can be accurately positioned at a predetermined position on the pad portion.

According to another preferred embodiment of the invention,
The pad portion has a circular shape, and the second portion is positioned at the center of the pad portion.

According to another preferred embodiment of the invention,
The area ratio between the first portion and the second portion on the upper surface of the pad portion is 5: 1 to 100: 1.

  As described above, according to the present invention, an object to be adsorbed such as a semiconductor wafer or a glass panel for FPD can be adsorbed without using complicated equipment.

It is a perspective view showing an adsorption system provided with an adsorption board concerning an embodiment of the present invention. It is sectional drawing of the suction disk concerning embodiment of this invention. It is a top view of the holding | maintenance part of the suction cup concerning embodiment of this invention. It is a top view which shows an example of the pad part by embodiment of this invention. It is a top view of the pad part by the modification of this invention.

  Hereinafter, a suction disk according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a suction system including a suction disk according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the suction disk according to an embodiment of the present invention.
As shown in FIGS. 1 and 2, the suction system includes a suction plate 1 and a pump 3 serving as a vacuum source connected to the suction plate. The suction disk 1 includes a pad portion 7 on which a semiconductor wafer 5 that is an object to be attracted is placed, and a holding portion 9 for holding the pad portion 7. The suction disk 1 is connected to the pump 3 via a connector 11 such as a hose.

  The pad portion 7 has a disk shape with two flat circular surfaces each having an upper surface 7a and a lower surface 7b, and the semiconductor wafer 5 can be placed on the upper surface. In the present embodiment, the pad portion 7 has a dimensional shape on the upper surface 7a that is substantially the same as that of the circular semiconductor wafer 5 that is an object to be adsorbed. Further, as will be described later, the pad portion 7 is arranged at the center portion and has a relatively small amount of gas permeation, and a second portion that is disposed around the first portion L and has a relatively large amount of gas permeation. And a portion H.

  The holding portion 9 has a thick disk shape larger in diameter than the pad portion 7 and includes a concave portion that opens upward in the center. In detail, the holding | maintenance part 9 has the 1st circular dent 13 which came to receive a pad part on the upper surface. The first circular recess 13 is formed by cutting out the inner peripheral side of the side wall 9a of the holding portion 9 into a rectangular shape. The first circular recess 13 has a diameter substantially the same as the outer diameter of the pad portion 7, and there is a gap between the pad portion 7 and the side wall of the first circular recess 13 when the pad portion 7 is received. It is not formed.

FIG. 3 is a top view of the holding unit 9 of the suction disk according to the embodiment of the present invention.
As shown in FIGS. 2 and 3, the holding portion 9 is provided continuously below the first circular recess 13 and includes a second circular recess 15 having a smaller diameter than the first circular recess 13. . The second circular recess 15 is covered with the pad portion 7 when the pad portion 7 is fitted into the first circular recess 13, and is formed by the second circular recess 15 and the pad portion 7. The ceiling of the space 17 is formed by the lower surface 7 b of the pad portion 7.

  In addition, an opening 15 a to which the connector 11 is connected is formed on the bottom surface of the second circular recess 15. With such a configuration, the holding unit 9 fluidly communicates the pores of the pad unit 7 with the pump 3 through the space 17 formed by the second circular recess 15 and the lower surface 7b of the pad unit 7.

  FIG. 4 is a top view showing an example of the pad portion 7. The pad portion 7 is formed of a porous carbon composite. Specifically, the pad portion 7 is formed by the first portion L formed by the first porous carbon having a predetermined gas permeation amount and the second porous carbon having a larger gas permeation amount than the first porous carbon. The formed second portion H is integrally formed.

  The first portion L formed of the first porous carbon has a ring shape surrounding a circular (specifically, cylindrical) second portion H disposed in the center of the pad portion 7 when viewed from above. The second portion H is disposed in the central opening of the ring-shaped first portion L.

  Such a pad portion 7 has the same horizontal cross-sectional shape across the upper surface 7a and the lower surface 7b, that is, a cross-sectional shape in which the second portion H is arranged at the center of the ring-shaped first portion L. In the region occupied by the first portion L, the pad portion 7 configured in this manner exhibits the gas permeation amount of the first porous carbon in the direction from the upper surface 7a to the lower surface 7b, and the second portion H occupies. In the region, the gas permeation amount of the second porous carbon is exhibited in the direction from the upper surface 7a to the lower surface 7b.

Next, the gas permeation amount of the pad portion will be described in detail.
The gas permeation amount indicates the amount of gas that passes through the unit area region per unit time under a constant pressure. The gas permeation amount is determined by adjusting the open porosity [vol%] and the average pore diameter [μm] of the porous carbon measured by the Archimedes method. In order to adjust the open porosity [vol%] and the average pore diameter [μm] of the porous carbon, the pressure applied to the object to be molded is adjusted in the pressurizing step of the porous carbon manufacturing step.

Hereinafter, production examples of two types of porous carbon having different open carbon porosity [vol%] and average pore diameter [μm] are shown.
Open pores by adjusting the molding surface pressure when pressing self-sintering carbon with an average particle size of 20μm into the mold and pressing it, and firing the finished compact in a non-oxidizing atmosphere at a heating rate of 30 ° C / hr Two porous carbons with different rates and average porosity could be produced. Examples of porous carbon obtained by adjusting the molding surface pressure during molding are shown in Table 1 below.

  As shown in Table 1, by increasing the molding surface pressure during molding, it is possible to produce porous carbon having a low open porosity, a small average pore diameter, and a small amount of gas permeation. In addition, by reducing the molding surface pressure during molding, it is possible to produce porous carbon having a high open porosity, a large average pore diameter, and a large gas permeation amount.

  In the example shown in Table 1 above, the ratio of the gas permeability of the first porous carbon and the gas permeability of the second porous carbon is about 1:20 to 1: 300.

  As a means for adjusting the gas permeation amount by adjusting the open porosity of the porous carbon, there is a method of adding a resin that decomposes and vaporizes when the molded body is fired.

Next, the operation of the suction system including the suction disk 1 will be described in detail.
In order to attract the semiconductor wafer to the suction disk 1, first, the semiconductor wafer 5 is placed on the upper surface of the pad portion 7 of the suction disk 1. At this time, for example, if the semiconductor wafer 5 has a disk shape, the center of the semiconductor wafer 5 and the center of the pad portion 7 are made to coincide. When the pump 3 is operated in this state, the air in the space 17 of the holding portion 9 is sucked in the direction of the pump 3 through the connector 11 connected to the pump 3.

  When the air in the space 17 is sucked, air is sucked from the pores of the first porous carbon and the second porous carbon of the pad portion 7, and adsorption of the semiconductor wafer 5 to the pad portion 7 is started. . When adsorption of the semiconductor wafer 5 is started, first, a portion of the semiconductor wafer 5 on the upper surface of the second portion H composed of the second porous carbon having a large gas permeation amount, that is, the vicinity of the center of the semiconductor wafer 5 is detected. Adsorbed to the pad portion 7.

  At this time, as described above, the suction speed of the second portion H is sufficiently higher than the suction speed of the first portion L. Therefore, even if the semiconductor wafer 5 is not in contact with the upper surface of the second portion H, the semiconductor wafer The vicinity of the center of 5 is first sucked into the pad portion 7. Next, suction of the semiconductor wafer 5 is started in the first portion L, which has a lower suction speed than the second portion H.

  Thus, first, the vicinity of the center of the semiconductor wafer 5 is sucked and fixed firmly by the second portion H, and then the portion other than the center of the semiconductor wafer 5 is sucked, so that the semiconductor wafer 5 is sucked in two stages. Thereby, even if the semiconductor wafer 5 placed on the pad portion 7 is bent, it is possible to prevent stress from being concentrated on a part of the semiconductor wafer 5.

  Further, when the semiconductor wafer is released from the suction plate 1, the pump 3 is switched to send air from the pump 3 to the suction plate 1. Thereby, first, the portion of the semiconductor wafer 5 on the upper surface of the second portion H composed of the second porous carbon having a relatively large gas permeation amount in the pad portion 7, that is, the vicinity of the center of the semiconductor wafer 5 is the pad portion 7. Released from.

  When the center of the semiconductor wafer 5 is released from the pad portion 7, a space is formed between the pad portion 7 and the upper surface of the second portion H, and the inside of the space becomes high pressure. When the inside of the space becomes high pressure, the semiconductor wafer 5 (portion in contact with the first portion L) around the space is gradually separated from the pad portion 7 by the pressure in the space, and the space is Begins spreading in the circumferential direction. When the space is expanded, the internal pressure is reduced, but air is sufficiently fed from the first portion L until the space is expanded to some extent. As a result, the remaining portion in contact with the first portion L is gradually released from the pad portion 7.

  Next, the portion of the semiconductor wafer 5 on the upper surface of the first portion L made of the first porous carbon having a relatively small gas permeation amount in the pad portion 7, that is, the peripheral portion of the semiconductor wafer 5 is released from the pad portion 7. The Finally, the semiconductor wafer 5 is lifted from the upper surface of the pad portion 7 by the compressed air sent from the upper surface of the pad portion 7. As a result, even when the semiconductor wafer is released, it can be gradually released from the center to the periphery of the semiconductor wafer, and the semiconductor wafer 5 can be prevented from being damaged when the semiconductor wafer 5 is released.

  As described above, according to the embodiment of the present invention, the position where suction is desired to be started is formed of the second porous carbon having a relatively large amount of gas permeation, and the other portion is the first porous body having a relatively small amount of gas permeation. By forming with carbon, suction can be started from a desired position regardless of the bent shape of the semiconductor wafer 5 placed on the pad portion 7. As a result, it is possible to prevent the semiconductor wafer 5 from being damaged during the adsorption.

  Without being limited to the above-described embodiment of the present invention, various changes and modifications can be made within the scope of the technical idea described in the claims.

  In the above-described embodiment, as described above, the pad portion 7 has substantially the same size and shape of the upper surface 7a as the suction surface of the semiconductor wafer 5 that is an object to be attracted. However, the size and shape of the upper surface 7a of the pad portion 7 can be changed as appropriate according to the size and characteristics of an adsorbate such as a semiconductor wafer or the required adsorption conditions.

  For example, the pad portion 7 may have a top surface 7 a having a larger size than the size of the suction surface of an object to be attracted such as the semiconductor wafer 5, that is, a circular shape having a larger diameter than the circular semiconductor wafer 5. In this case, the second portion H of the pad portion 7 is provided in a portion covered with the semiconductor wafer 5.

  By configuring the pad portion 7 in this way, the suction speed of the portion corresponding to the first portion L of the upper surface 7a of the pad portion 7 and the portion corresponding to the second portion H of the upper surface 7a of the pad portion 7 are determined. Since the difference with the adsorption speed can be effectively utilized, the semiconductor wafer can be more reliably prevented from being damaged.

  Moreover, you may change suitably the shape and dimension of the 2nd part H, and an arrangement position. For example, as shown in FIG. 5A, the second portion H may be set to have a larger diameter than that of the above embodiment. In addition, it is preferable that the ratio of the size (area when viewed from above) of the first portion L and the second portion H is appropriately set between 5: 1 and 100: 1.

  Further, as shown in FIG. 5B, the pad portion may be rectangular, the circular second portion H may be provided at the center, and the other portion may be the first portion L. In this case, the holding portion and the like are also rectangular according to the shape of the pad portion.

  Furthermore, as shown in FIG. 5C, the circular second portion H may be arranged offset from the center of the rectangular pad portion. These examples are effective when adsorbing a rectangular object to be adsorbed such as a glass panel for FPD.

  Further, as shown in FIG. 5 (d), the substantially square second portion H is arranged at the corner of the rectangular pad portion and the other portion is the first portion L, or shown in FIG. 5 (e). As described above, the substantially square second portion H may be arranged at the center position along the long side of the rectangular pad portion, and the other portion may be the first portion L.

  Thus, by positioning the second part H at the corner of the rectangular pad part or along one side, the object to be adsorbed can be easily positioned. For example, when positioning a relatively large object to be adsorbed such as a glass panel for FPD, align the corners of the pad and the corners of the glass panel, and hold the glass panel at this position. Is activated. Thereby, when a suction force acts on the glass panel at the time of adsorption, it is possible to reliably prevent the glass panel from being displaced from the pad portion. Such actions and effects can be achieved when the second portion H is located at any position on the outer periphery of the pad portion,

  Further, as shown in FIG. 5 (f) or (g), the second portion H is arranged along one side or two adjacent sides of the rectangular pad portion, and the other portion is the first portion L. Good. Even with such a configuration, the same operations and effects as the configuration of FIG. 5D and the like can be achieved.

  Moreover, in the said embodiment, although it was the structure in which the disk-shaped space 17 was formed between the pad part 7 and the 2nd circular dent 15 of the support part 9, the shape of the circular dent of a support part was changed. And it is good also as a structure by which the concentric several annular flow path fluid-connected to the pump 3 via the connector 11 is formed in the space between the pad part 7 and a support part.

  For example, in the above embodiment, porous carbon is used as the material constituting the pad portion, but other air-permeable materials such as porous ceramics can also be used.

DESCRIPTION OF SYMBOLS 1 Suction board 3 Pump 5 Semiconductor wafer 7 Pad part 9 Holding | maintenance part 13 1st circular dent 15 2nd circular dent L 1st part H 2nd part

Claims (4)

It is configured to be connected to a vacuum source, and is an adsorption disk for adsorbing a plate-shaped object to be adsorbed by operating this vacuum source,
A porous pad portion having an upper surface and a lower surface on which the object to be adsorbed is placed;
A holding part for holding the pad part,
The pad portion includes a first portion made of a first porous material having a predetermined amount of gas permeation from the upper surface to the lower surface of the pad portion, and a direction from the upper surface to the lower surface of the pad portion. And a second portion formed of a second porous material having a larger gas permeation amount than the first porous material,
The holding portion is configured to directly connect the pores of the first porous material and the pores of the second porous material forming the pad portion from the lower surface side of the pad portion to the vacuum source.
A suction board characterized by that.   The suction pad according to claim 1, wherein the pad portion has a rectangular shape, and the second portion is positioned at a corner of the pad portion.   The suction pad according to claim 1, wherein the pad portion has a circular shape, and the second portion is positioned at a center of the pad portion.   2. The suction cup according to claim 1, wherein an area ratio between the first portion and the second portion on the upper surface of the pad portion is 5: 1 to 100: 1.

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