JP4678788B2 - Thin wafer transfer method - Google Patents

Description

  The present invention relates to a thin wafer transfer method for attracting a very thin thin silicon wafer and transferring or transferring the thin wafer to a predetermined position.

Recent semiconductor silicon wafers have been ground to a thickness of about 50 μm to 150 μm, and very thin wafers have been used.
As a conventional wafer transport method for sucking and transferring a wafer to a predetermined position by sucking a silicon wafer, for example, as proposed in Patent Document 1, a table for sucking and holding one surface of a wafer, and a suction to one surface of the table are used. A thin wafer transport suction hand that attracts the other surface of the held wafer and transfers or transports the wafer to a predetermined position, holds one surface of the wafer on the table, and holds the wafer transport suction hand on the upper surface of the wafer. The suction surface of the wafer transfer suction hand is operated in a vacuum, the suction force of the wafer transfer suction hand is moved in the wafer suction direction by the suction force, and the wafer is sucked and held on the suction surface. Break the vacuum on the table, release the wafer vacuum holding by the table, hold the wafer by the vacuum holding surface of the wafer transfer suction hand, and hold the wafer on the table. After retracting movement Luo predetermined amount above the wafer conveying the wafer transfer suction hand there is for transferring or conveying to a predetermined position.
Japanese Patent No. 3259251

However, when the suction surface of the wafer transfer suction hand, which is a very thin silicon wafer with a thickness of about 50 μm to 150 μm, is vacuum-operated and directly sucked and held on the suction surface, it must be in contact with the suction surface. Since the portion of the wafer is a single point, stress or impact is concentrated on that portion, and therefore, the crack of the wafer occurs beyond the limit of the bending strength.
Furthermore, when the outer peripheral edge of a very thin thin wafer with a plate thickness of about 50 μm to 150 μm is enlarged greatly, it has a chipped portion like a circular saw blade. When a thin wafer is transferred to or transported to a predetermined position by suction with a hand, the very thin thin wafer is sucked at the inner periphery first, and the outer peripheral portion is bent and warped or bent at the predetermined position. When the suction action is released during mounting, stress concentration occurs in the chipped portion such as a circular saw blade on the outer periphery that is bent and warped or bent, and the suction action is released at the predetermined position. Sometimes cracking was inevitable. Another possible cause of warping the thin wafer is thermal shrinkage during cleaning of the BG resin tape that adheres the outer periphery of the thin wafer to the thin wafer holding film.

An object of the present invention is to suck and hold a wafer on a suction surface by vacuuming the suction surface of a wafer transfer suction hand when sucking a very thin wafer and transferring or transporting the thin wafer to a predetermined position. Therefore, it is an object of the present invention to provide a thin wafer transfer method in which the portion of the wafer that comes into contact with the suction surface does not become one point, and the crack of the wafer does not occur beyond the limit of the bending strength.
Furthermore, when a very thin thin wafer is sucked and the thin wafer is transferred or transferred to a predetermined position, the very thin thin wafer at the time of suction is sucked and bent at the inner periphery first. When it is placed in a predetermined position, stress concentration occurs in a chipped part such as a circular saw blade on the outer periphery that hangs down and warps or bends when the suction action is released at the time of placement at a predetermined position. It is an object of the present invention to provide a thin wafer transfer method that does not break when releasing the adsorption action.

For this reason, the present invention provides a table for sucking and holding one surface of a thin wafer on the upper surface, and a thin wafer for transferring or transporting the thin wafer to a predetermined position by sucking the other surface of the thin wafer sucked and held on one surface of the table. A suction suction hand, wherein the table has a porous ceramic suction plate substantially corresponding to one surface of the thin wafer, a fluid communication chamber substantially corresponding to the other surface of the porous ceramic suction plate, and the fluid communication chamber and the communication passage. A vacuum pump, a vacuum break passage, and a water and air mixed fluid supply source that selectively communicate with each other via
One surface of the thin wafer is sucked and held on the porous ceramic suction plate to the table, the suction surface of the thin wafer transfer suction hand is positioned close to the upper surface of the thin wafer, and the fluid communication chamber and the communication path are formed. The vacuum breaking passage is selectively communicated with the vacuum breaking passage, and the fluid communication chamber and the communication passage are selectively communicated with the water / air mixed fluid supply source so as to be uniform on the other surface of the thin wafer. The mixed wafer of water and air is guided to float the thin wafer slightly, and then the thin wafer that has floated is adsorbed to the adsorption surface, and the thin wafer transfer adsorption hand has an adsorption surface that substantially corresponds to the upper surface of the thin wafer. And a plurality of wide outer peripheral adsorption air chamber circumferential grooves communicating with the first communication path and a plurality of narrow inner circumferential adsorption air chamber circumferential grooves communicating with the second communication path, respectively. And
The first communication path is selectively connected to a high vacuum vacuum pump or a low pressure pneumatic pump through a first throttle having a wide cross-sectional area,
The second communication passage is selectively connected to a vacuum pump having a low vacuum degree or the low-pressure pneumatic pump through a second throttle having a narrow cross-sectional area,
The suction surface of the thin wafer transfer suction hand is disposed close to the upper surface of the thin wafer, and the high vacuum vacuum pump and the low vacuum pump are operated to bring the thin wafer into the suction surface. Adsorbed,
Transfer or transfer the suction surface of the thin wafer transfer suction hand to the predetermined position,
By the thin wafer transfer method , the high vacuum degree and the low vacuum degree are broken, and the low pressure pneumatic pump is operated to place the thin wafer at the predetermined position . The problem described above has been solved.

  In the present invention, with this configuration, one surface of the thin wafer is sucked and held on the porous ceramic suction plate by the table, and the suction surface of the thin wafer transport suction hand is positioned close to the upper surface of the thin wafer sucked and held on the table. In addition, the fluid communication chamber and the communication path on the lower surface of the porous ceramic adsorbing plate are selectively communicated with the vacuum breakage passage to perform vacuum breakage, and the fluid communication chamber and the communication path are selectively communicated with a mixed fluid supply source of water and air. Since the thin wafer is slightly floated by guiding the fluid mixture of water and air uniformly to the other surface of the thin wafer, and then the thin wafer is sucked to the suction surface of the wafer transfer suction hand. The suction surface of the transport suction hand is vacuum operated and the wafer is not directly sucked and held on the suction surface, and the portion of the wafer that contacts the suction surface does not become one point, Cracking of the wafer becomes as providing a thin wafer transfer method do not occur beyond the limits of rupture strength.

Furthermore, the thin wafer transfer suction hand used in the thin wafer transfer method is:
The suction surface substantially corresponds to the upper surface of the thin wafer, and each of the suction surfaces has a plurality of wide outer peripheral suction air chamber circumferential grooves communicating with the first communication path and a plurality of widths communicating with the second communication path. A narrow inner circumferential adsorption air chamber circumferential groove,
The first communication path is selectively connected to a high vacuum vacuum pump or a low pressure pneumatic pump through a first throttle having a wide cross-sectional area,
The second communication passage is selectively connected to a vacuum pump having a low vacuum degree or the low-pressure pneumatic pump through a second throttle having a narrow cross-sectional area,
The suction surface of the thin wafer transfer suction hand is disposed close to the upper surface of the thin wafer, and the high vacuum vacuum pump and the low vacuum pump are operated to bring the thin wafer into the suction surface. Adsorbed,
Transfer or transfer the suction surface of the thin wafer transfer suction hand to the predetermined position,
Destroying the vacuum in the vacuum and low vacuum of the high degree of vacuum, and Ri by the low-pressure pneumatic said thinned wafer by operating the pump to which is adapted to placed in the predetermined position,
When attracting a very thin wafer and transferring or transporting the thin wafer to a specified position, when attracting a thin wafer, the outer periphery of the thin wafer is actively attracted to weaken the inner periphery of the thin wafer. Therefore, the inner periphery of a very thin thin wafer at the time of suction is sucked first, the outer periphery is kept horizontal without being bent, warped or bent, and has a wide cross-sectional area even if a vacuum leaks. By making it easy to exhaust through the first diaphragm, the thin wafer is kept without bending, and the surface tension due to the grinding water that enters between the thin wafer and the suction surface is canceled when the suction action is released when placed at a predetermined position. The low pressure positive pressure air for vacuum breakage was also activated from the inner peripheral suction air chamber groove so that the thin wafer was moved away from the suction surface by operating the low pressure pneumatic pump. Trick Stress concentration occurs in a chipped portion such as a circular saw blade on the outer periphery that sags and bends during adsorption, and may break when the adsorption action is released at a predetermined position. A thin wafer transfer method that does not occur is provided.

  Embodiments of the present invention will be described with reference to the drawings. 1 is a schematic side block diagram showing a pneumatic circuit diagram of a table and a thin wafer transfer suction hand used in a thin wafer transfer method according to an embodiment of the present invention, and FIG. 2 is a fluid communication chamber on the lower surface of the porous ceramic chuck of FIG. FIG. 3 is a schematic bottom view of the suction hand for transporting a thin wafer in FIG. 1. FIG. 3 is a fluid circuit diagram of a vacuum pump, a vacuum breaking passage, and a mixed fluid supply source of water and air.

The thin wafer transfer method of the embodiment of the present invention shown in FIGS. 1 to 3 includes a table 19 that sucks and holds one surface 28 of the thin wafer 2 on the upper surface, and an upper surface 20 of the thin wafer 2 that is sucked and held on the upper surface of the table 19. A thin wafer transport suction hand 1 for transferring or transporting the thin wafer 2 to a predetermined position by suction, and a table 19 is a porous ceramic suction plate 17 substantially corresponding to one surface 28 of the thin wafer 2, and the porous ceramic A fluid communication chamber 18 substantially corresponding to one surface 28 of the suction plate 17, and a vacuum pump 56 and a vacuum breakage passage selectively communicated from the fluid communication chamber 18 and the communication passage 39 via the electromagnetic switching valves 53, 52 and 54, respectively. 55 and has a mixing fluid source 57 of water and air, suction holds the one surface 28 of the thin wafer 2 onto the porous ceramic attraction plate 17 in the table 19, the thin wafer transport the suction hand 1 to the upper surface 20 of the thin wafer 2 The adsorption surface 11 of the Then, the fluid communication chamber 18 and the communication passage 39 are selectively communicated with the vacuum break passage 55 via the electromagnetic switching valve 52 to perform the vacuum break, and the fluid communication chamber 18 and the communication passage 39 are further connected to the electromagnetic switching valve 54. The water and air mixed fluid supply source 57 is selectively communicated with each other so that the water and air mixed fluid is uniformly guided to the other surface 28 of the thin wafer 2 to slightly float the thin wafer 2 (the upper surface of the table 19 and the suction surface). The distance D of 11 is several mm), and the thin wafer 2 that has floated next is adsorbed to the adsorption surface 11. 2a is the thin wafer holding film affixed to thin the wafer 2, 51 pressure gauge, 50 is a pressure switch, is adapted to rotate about an axis of rotation 29 by a spindle which tables 19 are not shown.

  With this configuration, the thin wafer transfer method according to the embodiment of the present invention is configured such that one surface of the thin wafer is sucked and held on the porous ceramic suction plate by the table, and the thin wafer transport suction hand is held on the upper surface of the thin wafer sucked and held on the table. The suction surface is closely positioned and the fluid communication chamber and the communication passage on the lower surface of the porous ceramic suction plate are selectively communicated with the vacuum break passage to perform a vacuum break. By selectively communicating with the mixed fluid supply source, the water and air mixed fluid is uniformly guided to the other surface of the thin wafer, the thin wafer is slightly floated, and then the floated thin wafer is attracted to the suction surface of the wafer transfer suction hand. The wafer that is in contact with the suction surface without vacuuming the suction surface of the wafer transfer suction hand and directly holding the wafer to the suction surface. Portion without a single point, cracking of the wafer becomes as providing a thin wafer transfer method do not occur beyond the limits of the transverse rupture strength.

As shown in FIGS. 1 to 3, the thin wafer transfer suction hand 1 used in the thin wafer transfer method of the embodiment of the present invention sucks the thin wafer 2 and transfers the thin wafer 2 to a predetermined position (not shown). Or in the suction hand 1 for transporting thin wafers to be transported,
The suction surface 11 substantially corresponds to the upper surface 20 of the thin wafer 2, and each of the suction surfaces 11 has a plurality of wide outer peripheral suction air chamber circumferential grooves 13 and second communication passages 14 communicating with the first communication passage 12. A plurality of narrow inner circumferential adsorption air chamber circumferential grooves 15 communicating with each other,
The first communication passage 12 is selectively connected to a high vacuum degree vacuum pump HVP30 or a low pressure pneumatic pump LP40 via a switching valve 4 via a first throttle 21 having a wide sectional area,
The second communication passage 14 is selectively connected to the vacuum pump LVP31 having a low degree of vacuum or the low pressure pneumatic pump LP40 via the second restrictor 22 having a narrow cross-sectional area, respectively, via the switching valve 4,
The suction surface 11 of the thin wafer transfer suction hand 1 is placed close to the upper surface 20 of the thin wafer 2 and the high vacuum pump HVP30 and the low vacuum pump LVP31 are operated to suck the thin wafer 2 into the suction surface. Adsorbed to 11,
Transfer or transfer the suction surface 11 of the thin wafer transfer suction hand 1 to a predetermined position (not shown),
By breaking the high vacuum and low vacuum, and operating the low-pressure pneumatic pump LP40 to place the thin wafer 2 at the specified position, the very thin thin wafer is adsorbed. When thin wafers are transferred or transported to a predetermined position, when thin wafers are attracted, the outer periphery of the thin wafer is actively attracted and the inner periphery of the thin wafer is weakened. The inner periphery of the thin wafer is sucked first, and the outer periphery sags down and does not warp or bend. Even if the vacuum leaks, it can be easily exhausted through the first diaphragm having a large cross-sectional area. In this way, the low-pressure pneumatic pump is operated to keep the thin wafer from bending and to cancel the surface tension caused by the grinding water that enters between the thin wafer and the suction surface when the suction action is released when placed in place. The Low pressure positive pressure air for vacuum breakage was also activated from the inner circumferential suction air chamber groove so that the thin wafer was separated from the suction surface, so that the thin wafer was kept horizontal during vacuum break and sag during suction as in the prior art Providing a thin wafer transfer method in which stress concentration occurs in a chipped portion such as a circular saw blade on the outer periphery that warps or bends, and does not break when releasing the adsorption action when placed at a predetermined position It became something to do.

As shown in FIG. 3, the diameters of the plurality of wide outer peripheral suction air chamber circumferential grooves 13 and the narrow inner peripheral suction air chamber circumferential grooves 15 of the suction surface 11 of the thin wafer transfer suction hand 1 gradually decrease from the outer periphery of the suction surface. By forming a plurality of concentric circles 131 to 155, the adsorption of the thin wafer 2 and the operation of the low pressure positive pressure air for vacuum break can be performed uniformly. The outer circumferential adsorption air chamber circumferential grooves 13 are 131 to 136, the inner circumferential adsorption air chamber circumferential grooves 15 are 151 to 155, and the outer circumferential adsorption air chamber circumferential grooves 131 to 136 are the two first communication passages 12. Thus, the base 6 communicates with another communication path (not shown). The inner circumferential adsorption air chamber circumferential grooves 151 to 155 communicate with another communication path (not shown) of the base 6 through the two second communication paths 14.

The schematic side block diagram which shows the pneumatic circuit diagram of the table used for the thin wafer conveyance method of embodiment of this invention, and the adsorption | suction hand for thin wafer conveyance. FIG. 2 is a fluid circuit diagram of a vacuum pump, a vacuum breakage passage, and a mixed fluid supply source of water and air that selectively communicate with the fluid communication chamber and the communication passage on the lower surface of the porous ceramic adsorption plate of FIG. 1. FIG. 2 is a schematic bottom view of the thin wafer conveying suction hand of FIG. 1.

Explanation of symbols

1: Thin wafer transfer suction hand, 2: Thin wafer, 2a: Thin wafer holding film
4, 53, 52, 54: switching valve, 11: suction surface, 12: first communication path,
13, 131-136: Wide outer peripheral adsorption air chamber circumferential groove, 14: Second communication passage
15, 151 to 155: narrow inner circumferential adsorption air chamber circumferential groove, 17: porous ceramic adsorption plate
18: Fluid communication chamber, 19: Table, 20: Upper surface of thin wafer, 21: First aperture
22: Second throttle, 30: High vacuum vacuum pump HVP
31: Low vacuum pump LVP , 39: communication path, 40: low pressure pneumatic pump LP
55: Vacuum break passage, 56: Vacuum pump, 57: Water and air mixed fluid supply source

Claims (1)

There is a table for sucking and holding one surface of a thin wafer on the upper surface, and a thin wafer transport suction hand for sucking and transferring the thin wafer to a predetermined position by sucking the other surface of the thin wafer sucked and held on one surface of the table. And
The table selectively communicates with the porous ceramic suction plate substantially corresponding to one surface of the thin wafer, the fluid communication chamber substantially corresponding to the other surface of the porous ceramic suction plate, and the fluid communication chamber and the communication passage. A vacuum pump, a vacuum break passage and a mixed fluid supply source of water and air,
One surface of the thin wafer is sucked and held on the porous ceramic suction plate to the table, the suction surface of the thin wafer transfer suction hand is positioned close to the upper surface of the thin wafer, and the fluid communication chamber and the communication path are formed. The vacuum breaking passage is selectively communicated with the vacuum breaking passage, and the fluid communication chamber and the communication passage are selectively communicated with the water / air mixed fluid supply source so as to be uniform on the other surface of the thin wafer. A thin wafer transfer method for guiding a fluid mixture of water and air to slightly float the thin wafer, and then attracting the floated thin wafer to the suction surface ,
The thin wafer transfer suction hand has a suction surface substantially corresponding to the upper surface of the thin wafer, and each of the suction surfaces has a plurality of wide outer peripheral suction air chamber circumferential grooves and a second groove communicating with the first communication path. A plurality of narrow inner circumferential adsorption air chamber circumferential grooves communicating with the communication path are provided,
The first communication path is selectively connected to a high vacuum vacuum pump or a low pressure pneumatic pump through a first throttle having a wide cross-sectional area,
The second communication passage is selectively connected to a vacuum pump having a low vacuum degree or the low-pressure pneumatic pump through a second throttle having a narrow cross-sectional area,
The suction surface of the thin wafer transfer suction hand is disposed close to the upper surface of the thin wafer, and the high vacuum vacuum pump and the low vacuum pump are operated to bring the thin wafer into the suction surface. Adsorbed,
Transfer or transfer the suction surface of the thin wafer transfer suction hand to the predetermined position,
A method of transporting a thin wafer, wherein the vacuum with a high degree of vacuum and the vacuum with a low degree of vacuum are broken, and the low-pressure pneumatic pump is operated to place the thin wafer at the predetermined position.

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