JP3955176B2 - Wafer fixing mechanism in spin processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer fixing mechanism in a spin processing apparatus for cleaning or etching a wafer surface while placing the wafer on a rotary table and rotating the wafer at a high speed.
[0002]
[Prior art]
For example, as shown in FIGS. 4 and 5, a conventional spin processing apparatus includes a plurality of spinners (3 in the illustrated example) along the outer peripheral edge of a wafer W on a rotating table 41 on which the wafer W is placed and rotated. This wafer fixing shaft 42 is rotatably arranged, and a wafer fixing pin 44 having a wafer holding groove 43 formed on the side surface is eccentrically installed at the top of the wafer fixing shaft 42. In the cleaning or etching process, each wafer fixing shaft 42 is rotated in the direction of the arrow as shown in FIG. 6A, and the wafer fixing pin 44 on the top surface of the shaft is moved outside the wafer W as shown in FIG. 6B. By pressing against the peripheral edge, the wafer W is sandwiched by the wafer holding groove 43 on the side surface of the pin, and the wafer W is pressed and held at a fixed position.
[0003]
[Problems to be solved by the invention]
However, the conventional apparatus described above, when performing a cleaning or etching of the wafer W held rotary table 41 by the wafer fixing pin 44 while a high speed, as shown in FIG. 6 (b), the wafer fixing pin 44 Since the wafer W is always in contact at the same position, there is a problem that the contact point between the wafer W and the wafer fixing pin 44 is not cleaned or etched, and cleaning or etching residue occurs in this portion. .
[0004]
The present invention has been made in order to solve the above-described problem. The wafer holding position can be changed during the rotation of the wafer, and the contact point between the wafer and the wafer holding groove, which has been a problem in the past, is cleaned. Alternatively, it is an object of the present invention to provide a wafer fixing mechanism in a spin processing apparatus that eliminates etching residues.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the wafer fixing mechanism of the present invention is a spin processing apparatus for cleaning or etching a wafer surface while placing the wafer on a rotary table and rotating the wafer at a high speed, along the outer peripheral edge of the wafer. A plurality of wafer fixing shafts are provided on a rotary table so as to be freely rotatable, and provided with shaft rotation driving means capable of freely rotating the wafer fixing shafts at a desired angle,
At the tip of the wafer fixing shaft, a part of the side surface is notched to form a wafer flank during loading / unloading of the wafer, and on the periphery of the shaft tip opposite to the wafer flank, A wafer holding groove that presses and holds the wafer in contact with the outer peripheral edge is formed concentrically with the shaft along the circumferential direction of the shaft, and the rotary table is rotated at a high speed while the wafer is pressed and held by the wafer holding groove. By rotating the wafer fixing shaft by a predetermined angle by the shaft rotation driving means during rotation, the wafer pressed and held by the wafer holding groove is rotated and moved by a predetermined angle, and the wafer outer peripheral edge and the wafer holding groove are The contact position is changed .
Further, the wafer flank is formed by an inclined surface, and the shaft rotation driving means is attached to a rotatable rotating shaft concentrically inserted in a table rotating shaft, and a tip end side of the rotating shaft, A gear mechanism that connects between the rotating shaft and each wafer fixed shaft to transmit the rotation of the rotating shaft to each wafer fixed shaft, and a change that is attached to the lower end side of the rotating shaft and converts vertical motion into rotational motion. It is constituted by a nut and a vertical motion generating means for generating a vertical motion and transmitting it to the change nut.
[0006]
In the case of the wafer fixing mechanism of the present invention having the above structure, the wafer fixing shaft can be rotated at an arbitrary angle by the shaft rotation driving means during the high-speed rotation of the rotary table. For this reason, as the wafer fixing shaft rotates, the wafer pressed and held by the wafer holding groove is also rotated by a distance corresponding to the rotation angle of the wafer holding groove, and the wafer and the wafer are held at a position different from the previous contact position. The groove comes into contact and presses and holds the wafer. Accordingly, it becomes possible to perform cleaning or etching while shifting the wafer holding position during high-speed rotation, and it is possible to prevent the occurrence of cleaning or etching residue as in the conventional case.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an embodiment of the present invention.
FIG. 1 is a schematic cross-sectional view of a spin processing apparatus provided with a wafer fixing mechanism of the present invention, and FIG. 2 is a diagram showing the structure of a wafer fixing shaft in FIG. In the figure, reference numeral 1 denotes a rotary table for placing a wafer W to be cleaned, and a table rotary shaft 2 for rotationally driving the rotary table 1 is fixed at the center of the lower surface of the rotary table 1. Has been. A support cylinder 4 is disposed on the outer periphery of the table rotary shaft 2 via a bearing 3, and the entire rotary table 1 is rotatably supported by the support cylinder 4.
[0008]
A pulley 24 is fixed to the table rotating shaft 2, and the rotating table 1 can be rotated at high speed by rotating the table rotating shaft 2 by a motor (not shown) via the pulley 24. Has been. Further, a rotary shaft 6 is rotatably inserted into the table rotary shaft 2 via a bearing 5, and a gear 7 is located at the tip of the rotary shaft 2 in the rotary table 1. It is fixed.
[0009]
On the other hand, on the rotary table 1, for example, three wafer fixing shafts 8 are erected along the outer peripheral edge of the wafer W so as to be rotatable at equal intervals of 120 degrees. A gear 9 is fixed to the lower end side of the wafer fixing shaft 8. The gear 9 is engaged with a gear 7 at the tip of the rotating shaft 6 via a gear 10, and the wafer is rotated by rotating the rotating shaft 6. The fixed shaft 8 is rotated so that the direction of the wafer fixed shaft 8 can be freely changed.
[0010]
The wafer fixing shaft 8 presses and holds the wafer W when rotating the rotary table 1 at a high speed. As shown in detail in FIG. The wafer flank 11 is formed at the time of loading and unloading the wafer, and the shaft tip peripheral surface opposite to the wafer flank 11 has a V-shaped cross section in contact with the outer peripheral edge of the wafer W. The wafer holding groove 13 is formed concentrically with the shaft along the circumferential direction. In the case of the illustrated example, the zenith portion 12 of the wafer fixing shaft 8 has a moon shape in a plan view by cutting out the wafer flank 11.
[0011]
A rotary cylinder 14 is splined to a lower end portion of the table rotation shaft 2 extending downward from the lower surface center position of the rotary table 1 by a spline 15 so as to be movable in the vertical direction. A vertical drive cylinder 17 is attached to the rotary cylinder 14 via a bearing 16, and a cam follower 18 is attached to the outer surface of the vertical drive cylinder 17 via a vertical guide mechanism (not shown). .
[0012]
An eccentric cam 20 is in contact with the cam follower 18, and the eccentric cam 20 is rotationally driven by an actuator 19 so that the vertical drive cylinder 17 and the vertical drive cylinder 17 can be rotated via a bearing 16 via the cam follower 18. The connected rotary cylinder 14 is configured to move in the vertical direction by a distance corresponding to the rotation angle of the eccentric cam 20.
[0013]
Further, a change nut 21 for converting the vertical movement of the rotary cylinder 14 splined to the table rotary shaft 2 into a rotary motion is fixed to the lower end portion of the rotary shaft 6 arranged inside the table rotary shaft 2. It is installed. The change nut 21 has a male threaded portion 22 formed on the outer peripheral surface thereof. By engaging the male threaded portion 22 with a female threaded portion 23 formed on the inner peripheral surface of the rotating cylinder 14, the vertical movement of the rotating cylinder 14 is achieved. Is converted into a rotational motion, and the rotary shaft 6 is rotated by an angle corresponding to the distance of the vertical movement.
[0014]
Next, the operation of the wafer fixing mechanism having the above structure will be described with reference to FIG. First, in an initial state in which the wafer W is not loaded and placed, the three wafer fixing shafts 8 are arranged such that the wafer flank 11 side is positioned on the center side of the rotating table 1 as shown in FIG. Is set. Therefore, in this state, when the wafer W is carried onto the turntable 1 by a wafer transfer robot (not shown) or the like, the wafer W can be positioned on the turntable 1 without contacting the wafer fixing shaft 8. As shown in FIG. 3A, the center position can be aligned with the rotary table 1.
[0015]
After the alignment of the wafer W is completed, the actuator 19 is driven to rotate the eccentric cam 20 by a predetermined angle, and the rotation connected to the vertical drive cylinder 17 and the bearing 16 through the cam follower 18. For example, the cylinder 14 is moved downward by a distance corresponding to the angle.
[0016]
When the rotary cylinder 14 is moved downward, the vertical movement is converted into a rotary motion by the change nut 21 meshing with the rotary cylinder 14, and the rotary shaft 6 to which the change nut 21 is fixed is moved in a predetermined direction by a predetermined angle. It is rotated. The rotational movement of the rotating shaft 6 is transmitted to the wafer fixing shaft 8 via the gear 7 at the tip of the rotating shaft 6, the gear 10 in contact therewith, and the gear 9, and each wafer fixing shaft 8 is shown in FIG. It is rotated by 90 degrees, for example, in the direction indicated by the arrow (A) in a).
[0017]
When the wafer fixing shaft 8 is rotated 90 degrees in the direction of the arrow (A), each wafer fixing shaft 8 is in the state shown in FIG. 3B, and the wafer holding groove 13 (formed at the tip of the wafer fixing shaft 8 ( The hatched portion is in contact with the wafer W in the state shown in the figure, and is in contact with the contact point P position. Therefore, the wafer W is supported at three points on the rotary table 1 at the contact point P of the wafer holding groove 13 of the three wafer fixed shafts, and is pressed and held at a fixed position.
[0018]
After the wafer W is pressed and held by the wafer holding groove 13 as described above, the wafer transfer robot or the like is retracted, a motor (not shown) is turned on, and the table rotating shaft 2 is rotated at high speed via the pulley 24. .
[0019]
When the table rotating shaft 2 is rotated at a high speed, the rotating table 1 fixed at the tip of the table rotates at a high speed, and the spline 15, the rotating cylinder 14, and the change nut 21 are connected to the table rotating shaft 2. The rotary shaft 6 connected via the rotary table 1 also rotates integrally with the rotary table 1 at a high speed.
[0020]
In this high-speed rotation state, a cleaning liquid, an inert gas, or the like is sprayed toward the front and back surfaces of the wafer W from a cleaning liquid injection mechanism or an inert gas injection mechanism (not shown), and the wafer W is cleaned.
[0021]
By the way, when the front and back surfaces are cleaned while rotating the wafer W at a high speed in the holding state as shown in FIG. 3B, the wafer holding groove 13 and the contact point P of the wafer W remain in contact with each other. Therefore, the contact point P is not sufficiently cleaned. In the conventional apparatus, this has been a big problem, but in the present invention, such a problem can be solved as follows.
[0022]
That is, after the cleaning process is performed for a predetermined time after rotating at high speed in the state of FIG. 3B, the actuator 19 is driven and the eccentric cam 20 while the cleaning process is continued by rotating the rotary table 1 at a high speed. Is further rotated by a predetermined angle, and the vertical drive cylinder 17 and the rotary cylinder 14 are moved further downward by a distance corresponding to the angle.
[0023]
When the rotary cylinder 14 is moved downward, the vertical movement is converted into a rotary motion by the change nut 21 meshing therewith, and the rotary shaft 6 to which the change nut 21 is fixed is further rotated by a predetermined angle. .
[0024]
The rotational movement of the rotary shaft 6 is transmitted to the respective wafer fixed shafts 8 through the gear 7, gear 10 and gear 9 at the tip of the rotary shaft 6, and each wafer fixed shaft 8 is shown in FIG. It is further rotated by 90 degrees in the direction indicated by the arrow (b). When the wafer fixing shaft 8 is further rotated by 90 degrees in the direction of the arrow (b), each wafer fixing shaft 8 is in a state as shown in FIG. 3C, and each wafer holding groove 13 is also rotated by 90 degrees. To do.
[0025]
When the wafer holding groove 13 is rotated 90 degrees, the wafer W pressed and held by the wafer holding groove 13 is also moved toward the arrow (c) direction by the distance corresponding to the rotation angle of the wafer holding groove 13. It is rotated together with. Accordingly, the wafer holding groove 13 and the wafer W are in contact with each other at the position of the contact point P ′ different from the contact point P so far, and are pressed and held. Accordingly, the portion of the contact point P that has been in contact with the wafer holding groove 13 until then is also cleaned.
[0026]
According to the wafer fixing mechanism according to the above-described embodiment, it becomes possible to perform the cleaning process by shifting the holding position of the wafer W during the high-speed rotation of the wafer W, as described above. It is possible to eliminate such a problem that cleaning residue is generated at the contact point of the groove.
[0027]
As described above, the wafer W is pressed and held by the wafer holding grooves 13 of the plurality of (three in the illustrated example) wafer fixing shafts 8 arranged along the outer peripheral edge of the wafer. It is desirable to hold the wafer W as elastic as possible so that the wafer W is not damaged as much as possible. Therefore, it is desirable that the wafer fixed shaft 8 has a material that can be slightly elastically deformed, a shaft diameter that can be elastically deformed, and a shaft shape.
[0028]
In the above example, the case where the wafer fixing shaft 8 is rotated by 90 degrees in order to change the contact point between the wafer W and the wafer holding groove 13 has been described as an example. However, the rotation angle is 90 degrees. The angle is not limited, and an optimum angle may be set according to the circumferential groove length of the wafer holding groove 13.
[0029]
In the above-described example, the tip of the wafer fixing shaft 8 is cut off by the inclined surface 11 to form the wafer flank 11 when the wafer W is loaded and unloaded. The method of forming the wafer flank 11 is an inclined surface. The method is not limited to the method using the above, and any shape may be used as long as it is possible to form a flank that the wafer W does not hit.
[0030]
【The invention's effect】
As described above, according to the wafer fixing mechanism of the present invention, since the holding position of the wafer can be changed during the rotation of the wafer, the cleaning of the contact point between the wafer and the wafer holding groove, which has been a problem in the past, or Etching residue can be eliminated, and a spin processing apparatus with better cleaning or etching effect can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a spin processing apparatus provided with a wafer fixing mechanism according to an embodiment.
2A and 2B show the structure of the wafer fixing shaft in FIG. 1, wherein FIG. 2A is a schematic enlarged side view, and FIG. 2B is a schematic enlarged plan view.
FIGS. 3A to 3C are explanatory views of a wafer fixing operation by the wafer fixing mechanism of the embodiment. FIG.
FIG. 4 is a schematic side view showing the structure of a conventional spin processing apparatus.
5A and 5B show a structure of a wafer fixing shaft in a conventional spin processing apparatus, wherein FIG. 5A is a schematic enlarged side view, and FIG. 5B is a schematic enlarged plan view.
FIGS. 6A and 6B are explanatory views of a wafer fixing operation in a conventional spin processing apparatus.
[Explanation of symbols]
W Wafer P Contact point before shaft rotation P ′ Contact point after shaft rotation 1 Rotary table 2 Table rotary shaft 4 Support cylinder 6 Rotary shaft 7 Gear 8 Wafer fixed shaft 9 Gear 10 Gear 11 Wafer flank 12 Zenith portion 13 Wafer holding Groove 14 Rotating cylinder 15 Spline 17 Vertical drive cylinder 18 Cam follower 19 Actuator 20 Eccentric cam 21 Change nut 22 Male thread part 23 Female thread part 24 Pulley

Claims (2)

In a spin processing apparatus that cleans or etches a wafer surface while rotating the wafer on a rotary table at a high speed,
A plurality of wafer fixing shafts are erected on a rotary table so as to be rotatable along the outer peripheral edge of the wafer, and provided with shaft rotation driving means capable of freely rotating the wafer fixing shaft at a desired angle,
At the tip of the wafer fixing shaft, a part of its side is cut away to form a wafer flank when loading and unloading the wafer, and on the peripheral surface of the shaft tip opposite to the wafer flank, A wafer holding groove that presses and holds the wafer in contact with the outer peripheral edge is formed concentrically with the shaft along the shaft circumferential direction ,
The rotary table is rotated at a high speed while the wafer is pressed and held by the wafer holding groove, and the wafer fixing shaft is rotated by a predetermined angle by the shaft rotation driving means during the high-speed rotation, so that the wafer holding groove is pressed and held. A wafer fixing mechanism in a spin processing apparatus , wherein the wafer is rotated and moved by a predetermined angle to change the contact position between the wafer outer peripheral edge and the wafer holding groove . The wafer flank (11) is formed by an inclined surface ,
The shaft rotation driving means includes a rotatable rotation shaft (6) concentrically inserted into the table rotation shaft (2), a front end side of the rotation shaft, and the rotation shaft and each wafer fixing shaft ( 8) and a gear mechanism (7, 9, 10) for transmitting the rotation of the rotary shaft to each wafer fixed shaft by connecting between the rotary shaft and the lower end of the rotary shaft (6). The spin processing apparatus according to claim 1, characterized by comprising: a change nut (21) for converting into a nut; and a vertical motion generating means (14-20) for generating a vertical motion and transmitting it to the change nut (21). Wafer fixing mechanism.

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