JPH07308856A - Absorption board structure of wafer machine - Google Patents

Abstract

PURPOSE:To provide an absorption board structure of a wafer machine capable of improving wafer machining precision and performing a stable machining operation because wafer can be infallibly absorbed and held without being effected by the flatness of the wafer surface. CONSTITUTION:A cylindrical body 42, which formed of an elastic raw material, such as a rubber plate, and existing in a specified length from the suction surface 24 of a suction plate 22 by expanding it in a skirt shape, is provided on the outer circumference of the suction plate 22. Thus, when a wafer 20 having cambers, wavinesses or steps on its surface is sucked and held on the surface 24, the cylindrical body 42 formed of an elastic raw material adheres to the wafer 20 surface and forms a shroud as making elastical deformations matching the cambers, waviness or steps on the weber 20 surface surface even if an gap is formed between the weber 20 surface and plate 24. Air and grinding water are prevented from being sucked from a suction groove because the gap formed between the wafer 20 surface and the plate 24 can be sealed by this shroud.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suction disk structure of a wafer processing machine, and more particularly, to a suction disk structure of a wafer processing machine which holds a wafer by suction when processing the wafer.

[0002]

2. Description of the Related Art A chamfering machine will be described as an example of a suction plate structure of a conventional wafer processing machine. As shown in FIG. 8, a suction disk 2 is supported on the tip of a rotating rotary shaft 1, and a suction groove 4 (see FIG. 10) is formed on a suction surface 3 of the suction disk 2. The suction groove 4 communicates with a suction device via a suction passage 5 formed in the suction plate 2 and a suction passage 6 formed in the rotary shaft 1. When chamfering the periphery of the wafer 7 sucked and held by the suction disk 2, a negative pressure is generated on the suction surface 3 of the suction disk 2 to hold the wafer 7 by suction.
While the grinding water is supplied to the polishing portion of the grindstone (not shown), the grindstone is applied to the peripheral edge of the wafer 7 to perform chamfering. Also, the suction board 2
The suction surface 3 of No. 3 serves as a reference surface for the chamfering process, and thus has high flatness. Further, in FIG. 10, the flat portion on the outer periphery of the suction surface 3 is for holding the wafer 7 having the orientation flat by suction, so that the grindstone does not hit the suction plate 2 when chamfering the flat portion of the wafer 7. I am trying.

[0003]

However, since the surface of the wafer 7 sucked and held by the suction disk 2 is not necessarily flat, in the case of the conventional suction disk structure, there is a gap between the suction surface 3 and the wafer 7 surface. When 8 is formed, air 9 and grinding water 9 are sucked from the suction groove 4 through the gap 8. As a result, the suction force for sucking and holding the wafer 7 is reduced, and the suctioned grinding water 9 enters the suction device, so that the suction capability of the suction device is reduced, and further, there is a drawback that the device easily breaks down. .

For example, when the wafer 7 is manufactured by cutting the ingot with a slicing device of an inner peripheral blade type blade, a warp or a slight waviness is apt to occur, and when cutting with a wire saw, a step is formed. It is easy to occur. Since the chamfering process of the wafer 7 is performed before the lapping process, it is rare that the surface of the wafer 7 to be chamfered is flat. FIG. 8 is a diagram in which a warped wafer 7 is suction-held on the suction disc 2, and FIG. 9 is a diagram in which a stepped wafer 7 is suction-held on the suction disc 2. 8 and 9
As can be seen from FIG. 3, even if the wafer 7 having a warp, undulation or step is sucked by the suction plate 2 having the suction surface 3 having high flatness, a gap 8 is formed between the suction surface 3 and the wafer 7 surface. Especially, since the periphery of the wafer 7 is easily bent downward,
A gap 8 communicating with the suction groove 4 is formed in this portion, and air 9 and grinding water 9 are sucked from this gap 8.

As a result, the adhesion between the surface of the wafer 7 and the suction surface 3 deteriorates and the suction force decreases, so that when the wafer 7 deviates from the normal suction position of the suction plate 2 or the suction force further decreases, during chamfering processing. There arises a problem that the wafer 7 is repelled from the suction disk 2 by the rotational force of the whetstone. Also,
When the peripheral edge of the wafer 7 bends downward, the peripheral edge of the wafer 7 does not contact the grindstone at a correct angle, which causes a problem that the chamfering accuracy of the wafer 7 deteriorates.

The present invention has been made in view of the above circumstances. Since the wafer can be reliably sucked and held without being affected by the flatness of the wafer surface, the processing accuracy of the wafer is improved and stable processing is performed. An object is to provide a suction plate structure of a wafer processing machine that can be operated.

[0007]

In order to achieve the above-mentioned object, the present invention is a suction plate structure of a wafer processing machine for processing a wafer while holding the wafer on the suction surface of the suction plate by suction force. In the above, the outer circumference of the suction plate is provided with a cylindrical body which is made of an elastic material and which is expanded in a skirt shape and extends for a predetermined length from the suction surface.

[0008]

According to the present invention, a cylindrical body which is made of an elastic material and which is expanded in a skirt shape and extends a predetermined length from the suction surface is provided on the outer circumference of the suction plate. As a result, when a wafer having a warp, undulation, or a step on the wafer surface is suction-held on the suction surface, even if there is a gap between the wafer surface and the suction surface, the cylindrical body formed of the elastic material is used. While being elastically deformed according to the warp, undulation, or step of the surface, the wafer is in close contact with the wafer surface to form an enclosure along the outer periphery of the wafer surface. With this enclosure, the gap formed between the wafer surface and the suction surface can be sealed, so that air and grinding water can be prevented from being sucked from the suction groove. Further, since air and grinding water are not sucked, the suction force of the suction surface is increased, the adhesion between the suction surface and the wafer surface can be improved, and in particular, the downward bending of the wafer periphery can be eliminated. .

By forming a substantially V-shaped groove on the outer circumference of the suction disk and fixing the cylinder with an O-ring fitted in the groove, or by integrally molding the O-ring and the cylinder,
The cylinder can be easily attached and detached from the suction board. Accordingly, when the tubular body is damaged or the elastic force of the tubular body is reduced, the tubular body can be easily replaced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a suction plate structure of a wafer processing machine according to the present invention will be described in detail below with reference to the accompanying drawings. In FIG. 1, an example of a chamfering machine will be described below as an example of an embodiment of a suction plate structure of a wafer processing machine of the present invention. As shown in FIG. 1, the chamfering machine mainly rotates around a suction device 26 that suction-holds the wafer 20 on the suction surface 24 of the suction disc 22 by a suction force and a peripheral edge of the wafer 20 suction-held by the suction disc 22. However, the grinding wheel device 30 includes a grinding wheel 28 that abuts and chamfers the grinding wheel 28, and a grinding water nozzle 34 that supplies the grinding water 32 to the grinding wheel 28 when the wafer 20 is chamfered. Further, the adsorption device 26 is
The suction disk 22 is supported on the tip of the rotating rotary shaft 36, and the suction groove 24 shown in FIG. 9 is formed on the suction surface 24 of the suction disk 22. The suction groove 4 includes a suction passage 38 formed in the suction plate 22 and a suction passage 40 formed in the rotary shaft 36.
Through the suction device. As a result, when the suction device is operated, the suction surface 24 of the suction plate 22 has a negative pressure, and the suction force holds the wafer 20 by suction. Also,
When chamfering the periphery of the wafer 20, the wafer 2
The suction disk 22 holding and holding 0 is rotated, the rotating grindstone 28 is applied to the peripheral edge of the wafer 20, and the grinding water 32 is supplied from the grinding water nozzle 34 to the grindstone 28.

According to the present invention, as shown in FIGS. 1 and 2, the suction plate 22 is formed of an elastic material on the outer periphery of the suction plate 22 and expands in a skirt shape to extend a predetermined length from the suction surface 24. The existing cylinder 42 was provided. A rubber plate is preferable as the elastic material, and for example, silicone rubber or urethane rubber can be used. The elastic material is not limited to the rubber plate, and may be any material that elastically deforms to the same extent as the rubber plate. As shown in FIG. 3, the tubular body 42 is fixed by an O-ring 46 fitted in a V-shaped groove 44 formed in a substantially V-shape on the outer circumference of the suction plate 22. In this case, as shown in FIG. 4, the cylindrical body 42 and the O-ring 46 are integrally molded,
By fitting the O-ring 46 into the V-shaped groove 44,
2 may be mounted on the outer circumference of the suction plate 22.

Next, referring to FIG. 5, the thickness of the cylindrical body 42 and the protruding length of the cylindrical body 42 protruding from the suction surface 24 will be described. The plate thickness (A) of the cylindrical body 42 is 0.2 to 0. The range of 0.5 mm is preferable, and the angle (θ) of the V-shaped groove 44 is preferably within a range of 30 to 60 ° with respect to the suction surface 24, that is, the surface of the wafer 20 sucked by the suction surface 24. As a result, when the wafer 20 is suction-held on the suction surface 24, the cylindrical body 42 is elastically deformed according to the warp, undulation, or step of the wafer 20 surface, and is easily attached to the wafer 20 surface. Also, the cylinder 4
The projecting length (B) at which 2 projects from the suction surface 24 is 1 to 3.
The range of mm is preferred. The reason for this is that if the protrusion length (B) becomes too long, the wafer 20 will be affected by the elastic force of the cylindrical body 42.
On the contrary, it is difficult to elastically deform when it is too short. Therefore, the sealing property for sealing the gap 48 (see FIG. 6) formed between the suction surface 24 and the surface of the wafer 20 is not provided. become worse. Further, the depth (C) of the V-shaped groove 44 is preferably about 2 to 3 mm, and the tubular member 42 can be easily fixed by the O-ring 46. Further, when the tubular body 42 is mounted on the suction disk 22, it is preferable to use the tubular body 42 in a state in which the diameter of the tubular body 42 is expanded and extended by 10 to 20% from the normal state. The same applies to the case of the O-ring. As a result, since the tubular body 42 is mounted in a stretched state, the elastic force is increased and the adhesion to the surface of the wafer 20 can be improved.

Therefore, according to the suction plate structure of the wafer processing machine of the present invention, for example, when a warped wafer 20 is sucked and held on the suction surface 24 of the suction plate 22 as shown in FIG.
The cylindrical body 42 is elastically deformed in accordance with the warp of the wafer 20 surface and closely adheres to the wafer 20 surface to form an enclosure. With this enclosure, the gap 48 formed between the surface of the wafer 20 and the suction surface 24 can be sealed, so that the air and the grinding water 32 are prevented from being sucked from the suction groove through the gap 48. be able to. Furthermore, air and grinding water 32
Is not sucked, the suction force of the suction surface 24 is increased, and the adhesion between the suction surface 24 and the surface of the wafer 20 can be improved, so that the flatness of the wafer 20 is improved,
In particular, as shown in FIG. 7, it is possible to eliminate the downward bending of the peripheral edge of the wafer 20, which is mainly caused by the warp.

As described above, the suction plate structure of the wafer processing machine according to the present invention allows the wafer 20 to be held without being affected by warpage, undulation, step, etc. of the surface of the wafer 20 sucked and held by the suction surface 24 of the suction plate 22. It can be surely sucked and held by the suction plate 22. Therefore, the flatness of the wafer 20 adsorbed to the adsorption surface 24 is improved, and in particular, the downward bending of the peripheral edge of the wafer 20 is eliminated, so that the peripheral edge of the wafer 20 correctly contacts the grindstone 28 as shown in FIG. And as a result of this,
The chamfering accuracy of the wafer 20 can be improved and a stable chamfering operation can be performed.

Further, a V-shaped groove 44 is formed on the outer circumference of the suction plate 22 and an O-ring 46 fitted in the V-shaped groove 44 is used to form the cylindrical body 42.
The cylindrical body 42 can be easily attached to and detached from the suction plate 22 by fixing or by integrally forming the O-ring 46 and the cylindrical body 42. As a result, the cylindrical body 42 is damaged or the cylindrical body 4
If the elasticity of No. 2 is reduced, it can be easily replaced with a new cylinder 42. Further, by making the tubular body 42 detachable from the suction disc 22, the manufacturing cost can be reduced as compared with the case where the tubular body 42 and the suction disc 22 are integrally molded.

Although the chamfering machine has been described in the present embodiment, the present invention can be applied to all wafer processing machines that process a wafer in a state where the wafer is suction-held on a suction plate. The numerical values such as the thickness of the cylinder shown in this embodiment are preferable examples and are not limited to these numerical values. Further, in this embodiment, the cylindrical body is fixed to the outer circumference of the suction plate with an O-ring,
Although it can be attached and detached, it may be fixed by adhering it with an adhesive or the like.

[0017]

As described above, according to the suction plate structure of the wafer processing machine of the present invention, the suction plate is formed of an elastic material on the outer periphery of the suction plate, and is expanded in a skirt shape to extend from the suction surface. Since the cylindrical body extending for a predetermined length is provided, the wafer can be securely sucked and held on the suction plate without being affected by the flatness of the wafer surface. As a result, the processing accuracy of the wafer can be improved and a stable processing operation can be performed.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a chamfering machine as an example of an embodiment of a suction plate structure of a wafer processing machine according to the present invention.

FIG. 2 is a perspective view of the suction cup structure of the present invention in which a cylinder is attached to the suction cup.

FIG. 3 is a partial cross-sectional view showing a method of fixing a cylindrical body to a suction disc.

FIG. 4 is a partial cross-sectional view showing another method of fixing the cylindrical body to the suction cup.

FIG. 5 is a partial cross-sectional view showing a preferable form of a cylinder.

FIG. 6 is a state diagram showing a state in which the gap between the suction surface of the suction plate and the wafer surface is sealed by a cylinder.

FIG. 7 is a state diagram showing a state in which the downward bending of the peripheral edge of the wafer suction-held on the suction surface of the suction disk has disappeared.

FIG. 8 is a partial cross-sectional view showing a state in which a warped wafer is suction-held by a suction-disc structure of a conventional wafer processing machine.

FIG. 9 is a partial cross-sectional view showing a state in which a wafer having a step is suction-held by a suction plate structure of a conventional wafer processing machine.

FIG. 10 is a plan view showing the shape of a suction groove formed on the suction surface of the suction disk.

[Explanation of symbols]

 20 ... Wafer 22 ... Suction plate 24 ... Suction surface 28 ... Whetstone 34 ... Grinding water nozzle 36 ... Rotation shafts 38, 40 ... Suction passage 42 ... Cylindrical body 44 ... V-shaped groove 46 ... O-ring 48 ... Gap

Claims (3)

[Claims] 1. A suction plate structure of a wafer processing machine for processing a wafer in a state in which a wafer is sucked and held on a suction surface of a suction plate by a suction force, wherein the outer periphery of the suction plate is made of an elastic material. In addition, a suction plate structure for a wafer processing machine, characterized in that a cylindrical body which is expanded in a skirt shape and extends from the suction surface by a predetermined length is provided. 2. The suction of the wafer processing machine according to claim 1, wherein a substantially V-shaped groove is formed on the outer periphery of the suction plate, and the cylindrical body is fixed by an O-ring fitted in the groove. Board structure. 3. The suction plate structure for a wafer processing machine according to claim 2, wherein the cylindrical body and the O-ring are formed as an integral structure.