JP2001291688A - Wafer-stripping apparatus and wafer-polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stripping of a wafer automatically and surely, in a short time. SOLUTION: The wafer-polishing apparatus comprises a polishing head 2, having an annular retainer 10 for supporting a wafer W from the outer circumference thereof and holding the wafer by the surface tension of liquid supplied to the rear surface of the wafer, a means for polishing the surface of the wafer W held by the polishing head 2, and an apparatus 1 for stripping the wafer W from the polishing head 2, after polishing of the wafer is ended. The annular retainer 10 has a cut 11, made in the inner circumferential surface thereof and the stripping apparatus 1 comprises a stripping base 3, having a bank part 4 abutting against the retainer at the circumferential edge, a groove 5 made at a position which faces the retainer 10, where the distance to the inner circumferential edge 4a of the bank is shorter than the distance to the outer circumferential edge 4b thereof, while closing the opposite ends 5a, and an opening 6 for ejecting liquid from the inside of the groove 5 to the retainer 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer peeling device for peeling a wafer from a wafer holding device and a wafer polishing device provided with a peeling means, and more particularly to a waxless system for holding a wafer by surface tension of a liquid. The present invention relates to a separating unit that separates a wafer from a wafer holding device.

[0002]

2. Description of the Related Art In a wafer polishing process, in the case of a waxless method, a polishing head is rotated on a polishing cloth while a back surface of a wafer is held in close contact with a base plate of the polishing head by liquid surface tension or vacuum suction. Polishes the wafer surface. After the polishing step, the wafer needs to be peeled off from the polishing head. However, since the wafer is in close contact with the polishing head, the wafer cannot be easily peeled off.

Therefore, as a wafer peeling apparatus and method for peeling a wafer from such a waxless type polishing head, a wafer is manually removed from the polishing head using a jig such as tweezers, or a water gun is manually operated. 2. Description of the Related Art A method of removing a wafer by spraying a liquid on the wafer has been generally known.

Japanese Patent Application Laid-Open No. 11-233467 discloses that
Notches are provided at regular intervals on the inner peripheral surface of the annular retainer that supports the wafer from its outer periphery, and the liquid is cut by ejecting the liquid from the ejection port to these notches while rotating the polishing head at low speed. There is disclosed a wafer peeling apparatus and a wafer peeling method capable of easily peeling a wafer from a base plate of a polishing head by interposing a wafer back surface and a soft plate attached to a base plate from a notch portion.

[0005]

In such a wafer peeling apparatus, the wafer can be peeled from the polishing head without using a jig such as tweezers and without having to manually spray water with a water gun. This is advantageous in that it can prevent damage to the wafer and increase the efficiency of the wafer peeling operation.

However, since it is necessary to accurately inject the liquid into the notch of the retainer, if the position of the ejection mechanism slightly deviates from the rotation orbit of the notch due to the low-speed rotation of the polishing head, the cutting is performed. In some cases, the jetting liquid cannot be properly introduced into the notched portion, and as a result, it may be difficult to reliably separate the wafer.

Further, even when the wafer can be peeled, it takes a long time to complete the peeling because the jetting liquid is not properly introduced into the notch. On the other hand, even if the injection mechanism is located on the orbit of the notch,
Since the notches are provided at regular intervals, the ejected liquid strikes the notches only at regular intervals during the rotation of the polishing head, and it still takes time until the wafer is completely separated. In particular, the polishing process for the wafer,
When the processing of the peeling step is performed automatically, it is desired to perform the peeling operation in a shorter time.

The present invention has been made in view of the above problems, and has as its main object to provide a wafer peeling apparatus capable of automatically and reliably peeling a wafer. Another object of the present invention is to provide a wafer peeling apparatus capable of peeling a wafer in a short time.

[0009]

In order to achieve the above object, the invention according to claim 1 separates a wafer held by a wafer holding device by a surface tension of a liquid and a retainer supporting the wafer from the outer periphery. In a wafer peeling device, a peeling table on which the wafer holding device is placed, a groove portion formed by closing both ends at positions opposite to the retainer of the peeling table, and a liquid is ejected from inside the groove portion. Injection means,
It is characterized by having.

When the wafer holding device is placed on the peeling table, the position of the jetting means is shifted from a boundary surface between the retainer and the outer periphery of the wafer or a portion serving as a liquid passage to the back surface of the wafer, such as a notch formed in the retainer. However, in the invention according to claim 1, the groove of the peeling table is engraved at a position facing the retainer, and the ejecting means ejects the liquid from within the groove, so that the ejected liquid passes through the groove. Then, the liquid is introduced into a portion serving as the liquid passage. For this reason, even if the mounting position of the wafer holding device is slightly shifted, the jet liquid from the jet unit is surely introduced to the back surface of the wafer, and the wafer can be peeled by breaking the surface tension.

The configuration of the groove in the present invention is not particularly limited as long as it is cut at a position facing the retainer with the wafer holding device placed on the peeling table.
It does not matter whether or not it faces a portion serving as a liquid passage leading to the back surface of the wafer, such as a boundary between the retainer and the outer peripheral portion of the wafer or a cutout portion on the inner peripheral surface of the retainer.

For example, if the boundary between the retainer and the outer periphery of the wafer or a part of the notch of the retainer is located on the groove when the wafer holding device is mounted on the separation table, the injection means sprays from inside the groove. The ejected liquid is immediately ejected from the groove to the boundary surface or the notch, and the ejected liquid reaches the back surface of the wafer.

On the other hand, even when the boundary between the retainer and the outer periphery of the wafer or a part of the notch of the retainer is displaced from above the groove, the inside of the groove is filled with the jetting liquid. Is closed, so that the ejected liquid is dammed at both ends and overflows into the minute gap between the retainer and the peeling table. The jet liquid in the groove passes through the minute gap and is introduced into a portion serving as a liquid passage to the back surface of the wafer.

As described above, according to the present invention, when the wafer holding device is placed on the peeling table, regardless of whether or not the position of the groove portion is opposed to the portion serving as the liquid passage to the back surface of the wafer, the ejecting means can be used. The jetted liquid reaches the back surface of the wafer, so that the surface tension is destroyed and the wafer can be reliably separated.

Further, according to the present invention, the time required for the peeling operation can be reduced since the wafer can be reliably peeled irrespective of the position of the jetting means and the position of the groove. In particular, since the wafer can be surely peeled off, there is no need to rotate the wafer holding device, and the time required for the wafer peeling operation is further reduced as compared with the conventional apparatus.

The number of grooves in the present invention is not particularly limited, and a plurality of grooves can be provided on the peeling table.

The construction of the ejection means in the present invention is not limited as long as it ejects liquid from inside the groove. Examples of such an ejection unit include one or more ejection ports provided in the groove and a supply tank for introducing the ejection liquid into the ejection ports.

The wafer peeling device of the present invention can be applied to all wafer holding devices that hold a wafer by surface tension.

According to a second aspect of the present invention, in the wafer peeling apparatus according to the first aspect, the peeling table has a bank portion abutting on the retainer at a peripheral portion thereof, and the groove portion is formed of the bank portion. It is characterized in that a bank width up to an inner peripheral edge of the bank portion is engraved on a contact surface with the retainer so as to be shorter than a bank width up to an outer peripheral edge of the bank portion.

In the invention according to the second aspect, the bank provided on the peeling table comes into contact with the retainer, and the groove is provided on the bank.
Since the bank width from the groove to the inner peripheral edge of the bank portion is provided so as to be shorter than the bank width from the groove portion to the outer peripheral edge of the bank portion, the jet liquid flowing into the minute gap between the retainer and the bank portion is It reaches the inner edge of the bank earlier than the outer edge of the bank. Therefore, before the jetted liquid overflowing the groove reaches the outer peripheral edge of the bank portion and flows out to the outside, it is quickly introduced into the liquid passage such as a boundary between the outer periphery of the wafer and the retainer or a cutout portion of the inner periphery of the retainer, Reaching to the back surface is more reliable. Therefore, the separation of the wafer from the wafer holding device becomes more reliable, and the time for the separation operation is further shortened.

The bank portion of the peeling table in the present invention only needs to be in contact with the retainer, and does not need to match the size of the retainer. However, it is preferable that the entire width of the bank (the width of the bank from the inner peripheral edge to the outer peripheral edge of the bank) is slightly smaller than the width of the annular retainer. If the entire width of the bank is wider than the width of the ring-shaped retainer, when the surface tension on the back surface of the wafer is broken and the wafer tries to come off from the retainer, the bank will become an obstacle and the peeling of the wafer will be incomplete. Becomes However, if the entire width of the bank portion is configured to be smaller than the width of the annular retainer, the bank portion does not become an obstacle and the wafer surely falls into the concave portion of the peeling table formed by the entire circumference of the bank portion. This has the advantage that the peeling of the wafer becomes more complete. Also, there is an advantage that even when the mounting position of the wafer holding device on the peeling table is shifted, the jetted liquid can be more easily introduced into the cutout portion.

According to a third aspect of the present invention, there is provided a polishing head having an annular retainer for supporting a wafer from the outer periphery thereof, the polishing head holding the wafer by the surface tension of a liquid supplied to the back surface of the wafer, and the wafer held by the polishing head. A wafer polishing apparatus provided with a polishing means for polishing the surface of the wafer and a peeling means for peeling the wafer from the polishing head, wherein the annular retainer has a notch cut in the inner peripheral surface thereof, and The means may include a peeling table having a bank portion abutting on the retainer at a peripheral portion thereof, and a width of the bank portion up to an inner peripheral edge of the bank portion at an abutting surface of the bank portion with the retainer, the outer peripheral edge of the bank portion. A groove which is engraved at a position shorter than the bank width up to and has both ends closed, and an ejection means for ejecting liquid to the retainer from within the groove. Than it is.

The invention according to claim 3 is a wafer polishing apparatus in which the wafer peeling device according to claim 1 or 2 is applied to a means for peeling a wafer from a polishing head. The same operation and effect as those of the invention according to the first aspect are exerted.

Further, according to the present invention, when the polishing step and the peeling step of the wafer are automated, the peeling of the wafer from the polishing head can be shortened even if the mounting position of the polishing head slightly deviates from a desired position of the peeling table. Since it can be performed in a timely and reliable manner, complete automation can be achieved.

The number and configuration of the cutouts in the present invention are not particularly limited as long as they are cut on the inner peripheral surface of the annular retainer. The number of notches can be arbitrarily determined according to various conditions such as the diameter of the wafer. Also, the shape of the notch can be arbitrarily determined, such as a semicircular shape, a square shape, or the like. The size of the notch may be a constant size in the thickness direction of the retainer, or the diameter of the notch may be increased as the distance from the back surface of the wafer to the peeling base bank increases. In this case, since the opening of the notch approaches the groove, there is an advantage that the injection liquid can be more easily introduced.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. The wafer polishing apparatus according to the present embodiment is for mirror-polishing the surface of a silicon wafer cut from a silicon single crystal, and particularly has a diameter of about 4 mm.
It is intended for a so-called large diameter wafer of 00 mm. The wafer polishing apparatus according to the present embodiment includes a polishing head that holds a wafer W, a polishing plate that polishes the wafer surface by pressing a polishing head that rotates around a rotation axis, and that separates the wafer W from the polishing head after the polishing process. And a peeling device. In the present embodiment, a known polishing plate is used, and the description of the specific configuration is omitted.

FIG. 1 is a plan view showing a schematic configuration of the peeling apparatus of the present embodiment, and FIG. 2 is a sectional view showing a state in which a polishing head is mounted on the peeling apparatus of the present embodiment. FIG. 3 is a bottom view of the polishing head of this embodiment.

As shown in FIGS. 2 and 3, the polishing head 2
Is mainly composed of a base plate 8 fixed to the rotating shaft, an annular retainer 10 fixed to the base plate 8, and a soft plate 9 adhered to the base plate 8 with an adhesive. The polishing head 2 of the present embodiment holds the wafer W in a waxless manner. In particular, the polishing head 2 supplies water 12 between the back surface of the wafer and the soft plate 9 and holds the wafer W by the surface tension. I have.

The soft plate 9 is formed of a material such as polyurethane foam, and the soft plate 9
Is applied with water to hold the wafer W.

The inner diameter of the annular retainer 10 is substantially the same as the diameter of the wafer W.
Is further supported from the outer peripheral portion thereof to prevent positional deviation. Since the surface of the wafer W held by the polishing head 2 is polished by a polishing plate (not shown), the thickness of the annular retainer 10 is
Slightly thinner than the thickness.

In the polishing head 2 according to the present embodiment, as shown in FIGS.
Twenty-four semicircular cutouts 11 are formed at angular intervals of °. The notch 11 is used to introduce a liquid ejected from the wafer peeling device 1 described later between the back surface of the wafer and the soft plate 9 to break the surface tension of water and peel the wafer W from the polishing head 2. Used.

The wafer peeling apparatus 1 is provided with a peeling table 3 on which a polishing head 2 is placed. The peeling table 3 is located on the left and right in FIG. And has a bank portion 4 protruding therefrom. Here, FIG.
FIG. 3 is a partially enlarged cross-sectional view of a bank portion 4 and a retainer 10 when a polishing head 2 is placed on a separation table 3 in the present embodiment. As shown in FIGS. 2 and 4, when the polishing head 2 is placed on the separation table 3, the upper surface of the bank portion comes into contact with the lower surface of the retainer of the polishing head 2. The width C of the bank portion 4 is shorter than the width D of the annular retainer 10.

Each bank 4 is provided with a groove 5 extending in the circumferential direction of the peeling table 3, and the groove 5 is located slightly inward from the center of the bank 4. For this reason, the bank width A from the groove 5 to the bank inner peripheral edge 4a is shorter than the bank width B from the groove 5 to the bank outer peripheral edge 4b. Further, the groove 5 is closed at both end portions 5a, so that the liquid in the groove 5 is dammed at both ends 5a.

The bottom of the groove of each bank 4 is provided with a jet port 6 for jetting a liquid at two locations. The injection port 6 communicates with a liquid supply tank (not shown) outside the peeling table, and jets the liquid supplied from the tank toward the lower surface of the retainer from inside the groove.

The wafer peeling apparatus 1 configured as described above
A method of peeling the wafer W from the polishing head 2 using the method will be described. In the wafer polishing apparatus of the present embodiment, the polishing of the wafer W and the peeling of the wafer W are all automatically performed.

When the polishing step is completed, the rotation of the polishing head is stopped, and the polishing head 2 is separated from the polishing plate by the peeling device 1.
Move up and place. At this time, as shown in FIG.
The polishing head 2 is placed at a position where the notch 11 of the retainer 10 does not correspond to the groove 5 of the peeling table 3. In the present embodiment, the positions of the notch 11 and the groove 5 are shifted as described above, but the retainer 10 and the bank 4 are configured so that the notch 11 and the groove 5 coincide with each other. May be.

Next, while the rotation of the polishing head is stopped, the liquid is ejected from the ejection port 6 in the groove toward the lower surface of the retainer. At this time, since the groove 5 is closed by the lower surface of the retainer and both ends of the groove are closed, the liquid filled in the groove overflows into a minute gap between the lower surface of the retainer and the bank 4. Here, since the bank width A is shorter than the bank width B, the liquid reaches the bank inner peripheral edge 4a before the bank outer peripheral edge 4b. Therefore, before the liquid reaches the outer peripheral edge 4 b of the bank portion and flows out to the outside, the liquid is introduced into the notch portion 11 located near the inner peripheral edge 4 a of the bank portion and reaches the soft plate 9.

The liquid that has reached the soft plate 9 gradually penetrates between the soft plate 9 and the back surface of the wafer to destroy the surface tension. As a result, the wafer W is separated from the soft plate 9. At this time, the wafer W comes off the soft plate 9 and the retainer 10, but the width C of the bank 4
Is shorter than the width D of the annular retainer 10, the vicinity of the inner peripheral edge of the bank portion 4 does not become an obstacle, the wafer W is reliably separated, and the separation table 3 formed by the bank portion 4 is removed. It is accommodated in the recess 13.

As described above, in the wafer polishing apparatus according to the present embodiment, when the polishing head 2 is mounted on the peeling table 3, it is determined whether the position of the notch 11 of the annular retainer 10 and the position of the groove 5 match. Regardless, the liquid ejected from the ejection port 6 passes through the notch 11 and reaches the soft plate 9, so that the wafer W can be reliably separated.

Further, since the jetting liquid overflows after filling the inside of the groove and reaches the notch 11, even if the position of the injection port 6 does not correspond to the position of the notch 11, it is ensured. The jet liquid passes through the notch and reaches the back surface of the wafer, so that the wafer W can be reliably separated. Therefore, it is not necessary to rotate the polishing head.

Furthermore, the peeling of the wafer is made reliable and the rotation of the polishing head is not required, so that the time required for the peeling operation is shortened. Further, since the peeling of the wafer is completed in such a short time, the polishing process of the wafer W,
Complete automation of the peeling step can be achieved.

Although the wafer polishing apparatus of this embodiment targets a large-diameter wafer having a diameter of 400 mm,
Needless to say, the present invention can be applied to a wafer of 400 mm or less such as 00 mm and 200 mm.

Further, in the wafer polishing apparatus of the present embodiment,
Although the present invention is applied to a mirror polishing process of a wafer, the present invention is also applied to an SOI processing process, a flattening polishing (CMP) process of a semiconductor device manufacturing process, and a manufacturing process of a disk or a liquid crystal. Is also possible.

[0044]

EXAMPLE The wafer polishing apparatus described in the above embodiment was constructed as follows.

(Polishing Head) Outer diameter of annular retainer = 435.00 mm ± 1.59
mm Inner diameter of annular retainer = 401.00 mm ± 0.13
mm Width of annular retainer D = 17.00 mm Radius of notch: 4 mm (The notch has an angle of 15 °
24 at intervals)

(Peeling Table) Outer diameter of the peeling table = 435.00 mm ± 1.59 mm Bank width C = 14.6 mm Groove width = 5 mm Groove depth = 2 mm Bank width A from the groove to the inner peripheral edge of the bank = 2.1 mm Embankment width B from groove to outer periphery of embankment B = 7.5 mm Injection pressure of liquid = about 1 kg / cm ²

When a polishing head holding a 400 mm diameter silicon wafer stuck on water was placed on a peeling table and peeling was performed, the peeling operation of the silicon wafer was completed in about 30 seconds from the start of the work, and the wafer was surely removed. Was peeled off.

(Comparison with Conventional Wafer Peeling Apparatus) On the other hand, using a conventional wafer peeling apparatus, a silicon wafer having a diameter of 400 mm attached to a polishing head with water was placed on a peeling table, and the polishing head was rotated around a rotation axis. When the peeling operation of jetting the liquid to the notch portion of the retainer while rotating the wafer was performed, there were cases where the wafer could not be reliably peeled off.
It took 0 seconds.

[0049]

As described above, according to the present invention, there is provided a peeling table on which a wafer holding device is mounted, and a groove formed by closing both ends at positions facing the retainer of the peeling table. Ejection means for ejecting the liquid from inside the groove, so that even if the mounting position of the wafer holding device on the peeling table is slightly shifted, the wafer can be securely held regardless of the position of the ejection means and the position of the groove. It has the effect that it can be peeled off. Further, according to the present invention, there is an effect that even when the mounting position of the wafer holding device on the peeling table is slightly shifted, the time required for the wafer peeling operation is reduced.

Further, in the present invention, since the wafer can be peeled off reliably and in a short time, there is an effect that the wafer polishing step and the peeling step can be completely automated.

Further, according to the present invention, since the peeling of the wafer is completed in a short time, there is an effect that contamination such as drying spots and adhesion of particles to the wafer can be reduced. Furthermore, according to the present invention, since the wafer can be peeled off without complete contact, there is an effect that scratches and the like can be prevented from being generated on the wafer.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a wafer peeling apparatus of the present embodiment.

FIG. 2 is a cross-sectional view showing a state where a polishing head is mounted on the wafer peeling device of the present embodiment.

FIG. 3 is a bottom view of the polishing head of the embodiment.

FIG. 4 is an enlarged cross-sectional view of a bank portion in a state where a polishing head is mounted on the wafer peeling device of the present embodiment.

[Explanation of symbols]

 1: Peeling device 2: Polishing head 3: Peeling table 4: Bank portion 4a: Bank portion inner peripheral edge 4b: Bank portion outer peripheral edge 5: Groove portion 5a: Groove end portion 6: Injection port 7: Rotating shaft 8: Base plate 9: Soft plate 10: Annular retainer 11: Notch 12: Water 13: Detachment recess W: Silicon wafer

Continued on the front page (72) Inventor Junichi Matsuzaki 1 at 555 Nakanoya, Annaka-shi, Gunma Co., Ltd. Inside Super Silicon Research Laboratories (72) Inventor Kenro Hayashi 555 at Nakanoya, Annaka-shi, Gunma 1 Co., Ltd. Inside the Super Silicon Research Laboratories (72) Inventor Kimiyuki Kawasoe 555-1, Nakanotani, Annaka-shi, Gunma 1 Inside the Super Silicon Research Laboratories Co., Ltd. (72) Inventor Koichi Hatano 2-2-22 Kandatamachi, Chiyoda-ku, Tokyo (72) Inventor Yasuo Matsumoto 2-2-22 Kandatamachi, Chiyoda-ku, Tokyo F-term (reference) in Rapmaster STF Co., Ltd. 3C058 AB03 AB04 AC01 CB03 DA17

Claims (3)

[Claims] 1. A wafer peeling device for peeling a wafer held by a surface tension of a liquid on a wafer holding device and a retainer for supporting the wafer from the outer periphery, comprising: a peeling table on which the wafer holding device is mounted; A wafer peeling device, comprising: a groove formed by closing both ends at a position facing the retainer; and an ejection unit for ejecting a liquid from inside the groove. 2. The exfoliating table has a bank portion that contacts the retainer at a peripheral edge thereof, and the groove portion is a contact surface of the bank portion with the retainer,
2. The wafer peeling device according to claim 1, wherein a bank width up to an inner peripheral edge of the bank portion is cut at a position shorter than a bank width up to an outer peripheral edge of the bank portion. 3. 3. A polishing head having an annular retainer for supporting the wafer from the outer periphery thereof and holding the wafer by the surface tension of a liquid supplied to the back surface of the wafer, and polishing for polishing the surface of the wafer held by the polishing head. Means, and a peeling means for peeling the wafer from the polishing head, wherein the annular retainer has a cutout carved in the inner peripheral surface thereof, the peeling means, the peripheral portion In a peeling table having a bank portion abutting on the retainer, and on a contact surface of the bank portion with the retainer, a bank width up to an inner peripheral edge of the bank portion is larger than a bank width up to an outer peripheral edge of the bank portion. A wafer polishing apparatus, comprising: a groove engraved at a position to be shortened, the groove closed at both ends; and an ejection unit configured to eject liquid from inside the groove to the retainer.