JP3256808B2 - Peripheral polishing equipment for semiconductor wafers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a peripheral polishing apparatus used for finishing a peripheral edge of a semiconductor wafer such as a silicon wafer used for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for finishing the peripheral edge of a semiconductor wafer, there is a beveling apparatus in which a semiconductor wafer obtained by slicing an ingot is chucked one by one and ground with a bevel grindstone, or a plurality of wafers can be ground simultaneously. It is known (JP-A-62-136357, JP-A-62-136358 and JP-A-62-136358).
No. 136359).

[0003]

However, finishing of the peripheral edge of the semiconductor wafer by these beveling devices is grinding by a bevel grinding wheel. For this reason, the finished surface of the periphery is rough.

[0004] In recent years, the semiconductor industry has been moving toward ultra-precision, and there has been a problem of generation of chips, particles, and the like from the periphery of a semiconductor wafer ground by the above-mentioned conventional beveling apparatus.

For this reason, there is a demand for a peripheral processing apparatus capable of performing the same polishing as a mirror surface that does not generate chips or particles from the peripheral edge of the semiconductor wafer.

Accordingly, an object of the present invention is to provide a peripheral polishing apparatus for a semiconductor wafer which can polish the peripheral edges of a plurality of semiconductor wafers as efficiently as the mirror surface.

[0007]

In order to solve the above problems, a peripheral polishing apparatus for a semiconductor wafer according to the present invention comprises:
It has a plurality of peripheral grooves for polishing, has a horizontal polishing wheel that rotates in an appropriate direction, and has a plurality of peripheral grooves corresponding to each peripheral groove of the polishing wheel, and a plurality of peripheral grooves cooperate with the polishing wheel. Supporting the semiconductor wafer vertically,
And a feed roller that rotates each semiconductor wafer in an appropriate direction, a pressing device that can individually press the plurality of semiconductor wafers onto the polishing wheel and the feed roller, and an abrasive in each circumferential groove of the polishing wheel. And a polishing agent supply device.

[0008] It is preferable that the feed roller and the pressing device can move forward and backward with respect to the polishing wheel.

[0009]

In the above means, the semiconductor wafer is set one by one in each groove of the polishing wheel and the feed roller, and is stably held by three points of the polishing wheel, the feed roller and the pressing device. The periphery is pressed and polished in the peripheral groove of the polishing wheel to which the polishing agent is supplied while being rotated.

[0010] Further, by making the feed roller and the pressing device horizontally movable, the distance between the polishing wheel and the feed roller and the pressing device can be changed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a front view of a peripheral polishing apparatus for a semiconductor wafer showing one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a polishing wheel;
It is horizontally supported by a bearing bracket 3 and is rotated at a high speed in an appropriate direction (counterclockwise in FIG. 1) by a motor (not shown). The polishing wheel 1 is formed of a columnar material made of an elastic material having a polishing agent holding capacity such as urethane or non-woven fabric, and has an outer periphery on the periphery of the silicon wafer 4 as shown in FIG. Are provided at appropriate intervals in the axial direction.

On the side of the polishing wheel 1, a bearing bracket (not shown) erected on the machine base 2 supports the polishing wheel 1.
A feed roller 6, which is rotated at a low speed in an appropriate direction (counterclockwise in FIG. 1) by a motor (not shown), moves parallel to the polishing wheel 1 and moves back and forth with respect to the polishing wheel 1 as shown by an arrow A in the drawing. Is arranged so as to be horizontally movable. The feed roller 6 vertically supports the plurality of silicon wafers 4 in cooperation with the polishing wheel 1 and rotates each silicon wafer 4 in an appropriate direction (clockwise in FIG. 1). A plurality of peripheral grooves (not shown) that can accommodate the peripheral edge of the silicon wafer 4 are formed on the outer periphery of the polishing wheel 1.
Are provided corresponding to the respective circumferential grooves 5.

Reference numeral 7 denotes a pressing device which individually presses the plurality of silicon wafers 4 vertically supported by the polishing wheel 1 and the feed roller 6 on the polishing wheel 1 and the feed roller 6. A plurality of pressure arms 8 corresponding to the circumferential groove 5 of the wheel 1 and the like are provided. Each pressure arm 8 has a wafer holder 9 that engages with the peripheral portion of the silicon wafer 4 pivotally attached to a tip end (right end in FIG. 1). Each pressing arm 8 is pivotally supported at a base end (left end in FIG. 1) near a support shaft 10 parallel to the polishing wheel 1. The support shaft 10 is the same as the support shaft 10. It is horizontally mounted on a bearing bracket 12 erected on a slide plate 11 extending horizontally in the direction.
The slide plate 11 is supported by a guide block 13 placed on the machine base 2, and is provided so as to be horizontally movable as indicated by an arrow B in the drawing by a fluid pressure cylinder 15 attached to a casing 14 on the machine base 2. With the movement, the pressing arm 8 is moved forward and backward with respect to the polishing wheel 1. Each pressing arm 8 is placed on the slide plate 11.
Are provided individually or collectively by vacuum or magnetic force to hold the pressing arms 8 substantially horizontally. A lower end portion of a weight 17 for pressing the wafer holder 9 against the silicon wafer 4 is provided on an intermediate portion of each pressing arm 8 so as to be able to abut. Each weight 17 is attached to the casing 14. The positional relationship between the polishing wheel 1, the feed roller 6, and the pressurizing device 7, which are held by the weight holder 18 so as to be vertically movable, is provided as shown in FIG. That is, the feed roller 6 which can be moved horizontally has its center, this feed roller 6 and the polishing wheel 1.
A line segment formed between the center of the polishing wafer 1 and the center of the silicon wafer 4 is arranged at an angle of 80 ° with respect to a line segment formed between the center of the polishing wafer 1 and the center of the silicon wafer 4. The wafer presser 9 of the pressurizing device 7 that can move horizontally like the feed roller 6 has its pivot point on an extension of the line between the center of the polishing wheel 1 and the center of the silicon wafer 4. It is located and located. In order to stably hold and rotate the silicon wafer 4, not only the above positional relationship, but also as shown in FIG.
50-80 ° formed by a line segment formed by the center of the feed roller 6 and the center of the silicon wafer 4 and a line segment formed by the center of the polishing wheel 1 and the center of the silicon wafer 4.
Position the center of the feed roller 6 within the range of the angle of
Further, the pivot point of the wafer presser 9 is set to a central angle of 15 ° on one side centered on the center of the silicon wafer 4 on both sides of an extension of a line formed by the center of the polishing wheel 1 and the center of the silicon wafer 4. What is necessary is just to be located in the range made.

The casing 14 above the polishing wheel 1 and the feed roller 6 is provided with a rectangular wafer elevating port 19 as shown in FIG.
On the casing 14 surrounding the wafer lift 19,
A wafer carrier 20 transported by a wafer carrier mechanism (not shown) is provided so that the opening can be placed on the wafer carrier 20 so as to be loadable. Then, below the wafer elevator 19,
As shown in FIG. 5, a wafer elevating arm 21 that supports and elevates a plurality of silicon wafers 4 passing through the wafer elevating opening 19 is arranged. Wafer lifting arm 21
Is a fluid pressure cylinder 22 erected on the casing 14.
It is provided so as to be able to descend below the polishing wheel 1 and the feed roller 6.
On the other hand, on both sides of the elevating path of the wafer elevating arm 21,
Wafer guides 23 and 24 having a plurality of guide grooves for guiding the peripheral portions of the plurality of silicon wafers 4 supported and supported by the wafer lifting arm 21 are arranged respectively. The wafer guide 23 on one side (the left side in FIG. 5) is provided so as to be able to move up and down as shown by the arrow C in the drawing, and to be able to descend below the horizontal movement path of the wafer holder 9 of the pressurizing device 7, and further As shown by an arrow D in the drawing, the wafer guide 24 is provided so as to be able to move horizontally with respect to the wafer guide 24 on the side (the right side in FIG. 5).

In FIG. 1, reference numeral 25 designates an abrasive supply nozzle which constitutes a part of an abrasive supply device 26 for supplying an abrasive to the peripheral groove 5 of the polishing wheel 1, and is provided in a number corresponding to the peripheral groove 5. Have been. On the other hand, on the machine base 2 below the polishing wheel 1 and the feed roller 6, etc., an abrasive receiver 27 for receiving the abrasive dropped from the polishing wheel 1 or the like is provided. The obtained abrasive is stored in an abrasive tank 29 provided in the machine base 2 by a conduit 28 and is pumped by a pump 31 interposed in a conduit 30 connecting the abrasive tank 29 and the abrasive supply nozzle 25. It is configured to be used cyclically.

In the peripheral polishing apparatus having the above structure,
When the wafer carrier 20 is placed on the casing 14 as shown in FIG. 1 by the wafer carrier moving mechanism, the plurality of silicon wafers 4 accommodated therein are
After being supported by the wafer elevating arm 21 and being guided by the guide grooves of the wafer guides 23 and 24 on both sides with the lowering of the wafer elevating arm 21 as shown in FIG.
Each peripheral groove 5 of the polishing wheel 1 and the feed roller 6
It is supported vertically.

Next, one side of the wafer guide 23 is shown in FIG.
To move the slide plate 11 by operating the fluid pressure cylinder 15 of the pressurizing device 7 as shown by the solid line,
After the wafer holder 9 is engaged with the silicon wafer 4, the suction of the base end of the pressure arm 8 by the horizontal holding device 16 is released. Due to the release of the suction, the load of the wafer 17 is applied to the pressure arm 8, and the wafer presser 9 individually presses and holds the silicon wafer 4 against the polishing wheel 1 and the circumferential groove 5 of the feed roller 6.

After setting the silicon wafer 4 as shown in FIG. 1, the feed roller 6 is rotated at a low speed,
When the polishing wheel 1 is rotated at a high speed and the polishing agent is supplied from the polishing agent supply nozzle 25, the peripheral edge of the silicon wafer 4 is polished (polished) to be a mirror surface.

In the above-mentioned peripheral edge polishing, even if there is a notch such as an orientation flat on the peripheral edge of the silicon wafer 4, the peripheral edge is polished irrespective of the position of the notch because the silicon wafers 4 are individually pressed and held. be able to. As the polishing agent, alkali-based colloidal silica or a dispersion type siliceous polishing agent is used. Further, when the size of the silicon wafer 4 changes, the feed roller 6 and the wafer guide 2 on one side are changed.
3 and the pressing device 7 are appropriately moved in the horizontal direction.

The silicon wafer 4 on which the peripheral edge polishing has been completed is housed in the wafer carrier 20 by the operation procedure reverse to the setting procedure described above, and is automatically carried away by the wafer carrier mechanism.

In the above-described embodiment, the peripheral edge polishing of the silicon wafer has been described. However, if the material of the polishing wheel and the polishing agent are required, semiconductor wafers other than silicon can be used.
Although a dead weight is used as the pressurizing device, a cylinder pressurizing device may be used. Furthermore, although the wafers are individually pressed by the pressing arm and the wafer press, the use of an elastic body for the wafer press makes it possible to apply the collective press.

Here, the peripheral polishing apparatus described above,
The peripheral edge of a 6-inch silicon wafer is finished by a conventional beveling device, and each silicon wafer is oxidized in a horizontal diffusion furnace (1100 ° C. × 90 min in stee).
am), and the particles on the wafer surface after dip of the dilute HF were measured. The results are shown in Table 1.

[0025]

[Table 1] As is clear from Table 1, in the case of using the peripheral mirror polishing wafer by the peripheral polishing apparatus of the present invention, the generation of particles and the like can be reduced to about 1/10 compared with the peripheral beveling processing wafer by the conventional beveling apparatus.

[0026]

As described above, according to the present invention, one semiconductor wafer is set in each circumferential groove of the polishing wheel and the feed roller. While being kept stable,
Since the periphery is pressed and polished in the peripheral groove of the polishing wheel to which the abrasive is supplied by being rotated by the feed roller, the periphery of the plurality of semiconductor wafers can be polished as efficiently as the mirror surface.

Further, by making the feed roller and the pressing device advance and retreat with respect to the polishing wheel, the distance between the polishing wheel and the feed roller and the pressing device becomes variable, so that the size of the semiconductor wafer is reduced. Can respond to change.

[Brief description of the drawings]

FIG. 1 is a front view of a peripheral polishing apparatus for a semiconductor wafer showing one embodiment of the present invention.

FIG. 2 is a half sectional side view in which a part of a polishing wheel is omitted.

FIG. 3 is an explanatory diagram of an arrangement relationship between a polishing wheel, a feed roller, and a pressing device.

FIG. 4 is an explanatory diagram of an allowable arrangement relationship of a polishing wheel, a feed roller, and a pressing device.

FIG. 5 is an operation explanatory view of a main part of the peripheral edge polishing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing wheel 4 Silicon wafer 5 Peripheral groove 6 Feed roller 7 Pressurizing device 8 Pressing arm 9 Wafer presser 25 Abrasive supply nozzle 26 Abrasive supply device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B24B 9/00 601 H01L 21/304 621

Claims (2)

(57) [Claims] 1. A polishing wheel having a plurality of circumferential grooves for polishing and rotating in an appropriate direction, and a plurality of circumferential grooves corresponding to each circumferential groove of the polishing wheel. A plurality of semiconductor wafers vertically supporting each other, and a feed roller that rotates each semiconductor wafer in an appropriate direction, and a pressing device that can individually press the plurality of semiconductor wafers onto a polishing wheel and a feed roller. A polishing agent supply device for supplying a polishing agent to each peripheral groove of the polishing wheel. 2. The peripheral polishing apparatus for a semiconductor wafer according to claim 1, wherein the feed roller and the pressing device are capable of moving forward and backward with respect to the polishing wheel.