JP2009004579A - Polishing apparatus for semiconductor wafer notch end face, and polishing head used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology to polish a notch end face of a semiconductor wafer sufficiently, easily, and in a short time. <P>SOLUTION: The polishing apparatus for a semiconductor wafer notch end face includes a polishing head 17, a polishing head swinging arm 33, and a semiconductor wafer holding base 13. The polishing head 17 includes a driving roller which is rotate-driven by a driving device, at least one free roller which can be rotated, an endless polishing belt 18 which is tensioned between the driving roller and the free roller and travels over these rollers, and a tension application means for pressing the polishing belt 18 to apply tension thereto. The polishing head swinging arm 33 rotationally moves the polishing head 17, with the polishing belt 18 being in a state of traveling on a vertical plane, on a vertical plane around an abrasive contact portion wherein a notch 16 of the semiconductor wafer and the polishing belt 18 abut against each other. The semiconductor holding base 13 holds the semiconductor wafer 12 horizontally. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor wafer polishing technique, and more particularly to a polishing apparatus for a semiconductor wafer notch end face and a polishing head used in the apparatus.

  In order to indicate the direction of the crystal axis, a semiconductor wafer is provided with an orientation flat in which a part of the wafer is cut out in the crystal axis direction, or a notch that is a small V-shaped cutout at the peripheral edge of the wafer. Yes. In particular, recent wafers with larger diameters tend to be provided with small notches because the waste portion increases when the orientation flat is provided. As described above, since this notch is a small V-shaped notch, it is difficult to polish, and the conventional notch has not been polished.

  However, even if fine dust is generated, semiconductor wafers have a great influence on processing quality, so that advanced surface processing is required, and not only the outer peripheral portion of the wafer but also the notch mirror processing is required.

The conventional polishing apparatus for the end face of a semiconductor wafer notch in response to this notch mirror processing requirement rotates a disk-shaped polishing plate with a polishing pad fixed around it, and perpendicularly to the surface of the polishing pad around this polishing plate. Alternatively, it is performed by pressing a semiconductor wafer placed on a semiconductor wafer holding table arranged at an inclination (see, for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 7-68461 JP-A-8-168947

  However, in the conventional polishing apparatus described in Patent Documents 1 and 2, since the semiconductor wafer is arranged vertically or inclined on the surface of the polishing pad around the disk shape, the polishing on one side is finished. Thereafter, the semiconductor wafer is inverted and fixed to the semiconductor wafer holding table, and the same polishing must be performed on the other surface side, which requires time and effort for the polishing operation. Furthermore, the arc-shaped end face of the semiconductor wafer and the disc-shaped polishing pad of the polishing plate have a problem that the contact area is very small and it takes time to polish the notch of the semiconductor wafer.

  Also, the replacement of the polishing pad requires the same effort and time as described above for the replacement work of removing the polishing pad holder from the polishing bearing, further removing the polishing pad from the polishing pad holder, replacing it with a new polishing pad, and reattaching it to the apparatus. There is a problem that it requires.

  The present invention has been made in view of these problems, and it is possible to polish a notch end surface of a semiconductor wafer sufficiently and easily in a short time, and also to replace a polishing tool easily in a short time. An object of the present invention is to provide a polishing apparatus and a polishing head used therefor.

  In order to achieve the above object, the present invention proposes a polishing head for polishing a notch end surface of a semiconductor wafer, a driving roller that is driven to rotate by a driving device, and at least one or more free rollers that can rotate. A polishing head comprising: an endless polishing belt that runs on the drive roller and the free roller; and tension means that presses and tensions the polishing belt.

  If the polishing belt of this polishing head is in contact with the notch end surface of the semiconductor wafer, the polishing belt can be tensioned by pressing, so the polishing effect is increased at the polishing contact portion where the semiconductor wafer notch and the polishing belt are in contact, The polishing belt also enters the notch end surface cut into a V shape, and mirror polishing can be easily performed in a short time. Furthermore, this polishing head has a simple structure, and an endless polishing belt that runs on a drive roller and a free roller can be easily replaced.

  The tension means may include a tension pressure roller that presses the polishing belt by sliding movement, and a pressure drive unit that slides the tension pressure roller. The tension due to the pressing of the polishing belt is caused by a tension pressure roller that can be slid. Further, the tension pressure roller can be moved by pressure applied by a pressure driving unit.

  The pressure drive unit uses, for example, an air cylinder that is driven by air pressure that is finely adjusted by a precision regulator or the like. The motor actuator with a ball screw generally used can be illustrated.

  The tension means preferably further includes a pressure sensor. If an optimum pressure value for mirror polishing of the notch is obtained in advance and the pressure value is observed and maintained by a pressure sensor, high-quality polishing can be achieved.

  The pressure sensor is, for example, a small load cell using a piezoelectric element. An example of the pressure sensor is PS method (pressure range: 0 to 1.0 MPa) manufactured by Kyowa Denki.

  The polishing head is further connected with a polishing head swinging means for swinging the polishing head. The polishing head swinging means causes the polishing head to move on a vertical surface centering on the polishing contact portion of the polishing belt. Is preferably rotated.

  Further, the present invention proposes that the polishing head and the polishing head placed in a state in which the polishing belt runs on a vertical surface are provided with a polishing contact portion where the semiconductor wafer notch and the polishing belt contact each other. 1. A semiconductor wafer notch end surface polishing apparatus comprising: a polishing head swinging means for rotating a vertical surface about a center; and a semiconductor wafer holding table for holding the semiconductor wafer in a horizontal state.

  If the polishing head is rotated on the vertical surface about the polishing contact portion of the polishing belt by the polishing head swinging means, the upper surface and the lower surface of the notch can be sufficiently mirror-polished. As a result, the entire notch can be mirror-polished in a short time.

  The semiconductor wafer notch end surface polishing apparatus further includes semiconductor wafer swinging means for swinging the holding table in a horizontal direction, and the semiconductor wafer holding table is moved from the semiconductor wafer notch by the semiconductor wafer swinging unit. It is preferable to rotate on a horizontal plane around a polishing contact portion with which the polishing belt contacts.

  As described above, since the semiconductor wafer holding table is rotated on the horizontal plane around the polishing contact portion of the semiconductor wafer with the polishing belt by the semiconductor wafer swinging means, it is a small V-shaped notch. The left and right end surface portions of the notch can also be sufficiently mirror-polished easily in a short time.

  The semiconductor wafer swinging means includes a support leg for supporting the semiconductor wafer holding base, a holding base swinging arm having one end connected to a lower end portion of the support leg and extending in a horizontal direction, and the holding base swinging means. If the rotating shaft connected to the other end of the moving arm and the rotating shaft driving device for rotating the rotating shaft are configured, the device configuration can be simplified.

  Furthermore, it further comprises a rail on which the semiconductor wafer swinging means is placed, and a slider that moves on and off the rail in a direction in which the semiconductor wafer swinging means comes into contact with the polishing belt. Is preferred.

  Since the semiconductor wafer swinging means can move toward and away from the polishing belt, that is, move toward and away from the polishing belt, in addition to being used for setting the semiconductor wafer, the contact of the semiconductor wafer with the polishing belt can be adjusted. The degree of polishing can be adjusted.

  In the semiconductor wafer notch end surface polishing apparatus according to the present invention, the semiconductor wafer is placed on a horizontal surface and the notch end surface is polished so that the polishing belt runs on the vertical surface. However, the positional relationship is limited to this. For example, a semiconductor wafer may be mounted parallel to the vertical surface and polished. The point is that the polishing belt sufficiently abuts on the end face of the notch to increase the polishing efficiency.

  According to the present invention, since the traveling polishing belt is in tension and brought into contact with the end surface of the semiconductor wafer notch, which is a minute portion, the polishing contact portion can be widened, so that sufficient mirror polishing can be performed. Is.

  Further, the polishing can be sufficiently performed on the upper end surface and the lower end surface of the notch end surface by the polishing head swinging means.

  Further, the right and left portions of the end surface of the notch can be sufficiently polished by the semiconductor wafer swinging means.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  1 is a front view of a semiconductor wafer notch end surface polishing apparatus according to the present invention, FIG. 2 is a plan view of the semiconductor wafer notch end surface polishing apparatus, FIG. 3 is a front view of the polishing head according to the present invention, and FIG. FIG. 5 is a front view showing the operating state (horizontal position) of the polishing head, FIG. 6 is a front view showing the operating state of the polishing head (inclined position with the polishing contact portion down), FIG. Is a front view showing the operating state of the polishing head (inclined position with the polishing contact portion up), FIG. 8 is a plan view showing the swinging (turning) state of the semiconductor wafer, and FIG. It is a typical expansion perspective view.

  As shown in FIG. 1 and FIG. 2, a semiconductor wafer notch end surface polishing apparatus according to the present invention is mainly a wafer on which a semiconductor wafer 12 is placed in a horizontal state and is provided inside a housing 11 which is a hollow container. A holding table 13, a wafer rocking unit 15 (semiconductor wafer rocking means) that rocks the wafer holding table 13, and a polishing head 17 for polishing the end face of the semiconductor wafer notch 16 are provided. .

  The wafer holding table 13 is a dish-shaped one that holds and holds a disk-shaped semiconductor wafer in the horizontal direction, has a suction hole (not shown) on the table, and is a suction pump (see FIG. (Not shown).

  In addition, a polishing liquid, cooling liquid, and cleaning liquid supply nozzle (not shown) and a collection container (not shown) for discharging used liquid to the outside of the apparatus are held on the semiconductor wafer being polished. It is provided in the base 13 and its periphery.

  The wafer holding table 13 is coaxially mounted on the upper end surface portion of the rod-shaped support leg 21, and the lower end surface portion of the support leg 21 is mounted on one end side of the holding table swinging arm 22 that swings in the horizontal direction. ing.

  A rotating shaft body 23 is attached to the other end side of the holding base swing arm 22, and the extending direction of the rotating shaft of the rotating shaft body 23 is the contact between the semiconductor wafer notch end surface 16 and the polishing belt 18. It has become a part. For this reason, when the swinging state of rotating about the rotation axis is made, the semiconductor wafer 12 rotates about the contact portion (the position of the rotated semiconductor wafer is indicated by a chain line in FIG. Show).

  The rotating shaft body 23 is connected to a motor 25 and a belt 26 to rotate. The rotating shaft body 23, the motor 25, and the belt 26 are accommodated in a slider 27 on a holding base 29. The slider 27 can reciprocate horizontally on a slide frame 28 mounted horizontally in the housing 11. By this reciprocation, the notch 16 of the wafer 12 can come close to and contact with the polishing belt 18 and can be separated.

  The wafer swinging portion 15 is configured by the support leg 21, the holding base swinging arm 22, the rotating shaft body 23, the motor 25, the belt 26 and the slider 27.

  On the other hand, the polishing head 17 has a box shape with an endless polishing belt 18 and an inner plate 31a and an outer plate 31b provided at positions sandwiching the polishing belt from both sides, and the outer side of the inner plate 31a. Is provided with a polishing belt running motor 32 for running the polishing belt 18. The polishing belt running motor 32 is disposed on the opposite side of the inner plate surface 31a from the polishing contact portion of the polishing belt 18.

  One end of an L-shaped swing arm 33 extending in the horizontal direction is connected to the polishing belt running motor 32 on the inner plate 31a, and the other end of the swing arm 33 is connected to the housing 11. The rotating shaft body of the polishing head swing motor 36 attached to the swing mechanism frame 35 installed is connected.

  The pivot shaft of the pivot shaft of the swing motor 36 is positioned on a horizontal plane, and a polishing contact portion where the semiconductor wafer notch and the polishing belt are in contact is positioned in the extending direction. For this reason, when the swing motor 36 rotates, a swing motion is generated in which the polishing head rotates around the polishing contact portion.

  Next, the outline of the polishing head 17 will be described with reference to FIGS.

  The polishing head 17 is a thin plate-like box formed with a predetermined interval between the inner plate 31a and the outer plate 31b. Between the inner plate 31a and the outer plate 31b, an abrasive belt driving roller 51 rotatably attached to the inner plate 31a, and a pair of free rollers, an upper roller 52a and a lower roller 52b, are similarly provided. The plate 31a is rotatably attached.

  An endless polishing belt 18 is hung on the polishing belt driving roller 51, and the upper roller 52a and the lower roller 52b. The polishing belt driving roller 51 is connected to a coaxial driving pulley 53 projecting to the outside of the inner plate 31 a, and this driving pulley 53 is interlocked with the polishing belt running motor 32 by a belt 55.

  In this embodiment, the driving pulley 53 and the polishing belt running motor 32 are interlocked by the belt 55, but may be interlocked by a gear mechanism instead of the belt 55.

  When the polishing belt running motor 32 is operated, the polishing belt driving roller 51 rotates through the belt 55 and the driving pulley 53 so that the polishing belt 18 runs. A portion of the polishing belt 18 between the upper roller 52a and the lower roller 52b is exposed to the outside from the polishing head 17, and the exposed portion abuts against an object to be polished, for example, an end surface of a notch of a semiconductor wafer so as to polish. It has become.

  Two rollers positioned above and below to press and tension the polishing belt, that is, the upper tension pressing roller 56a and the lower tension pressing inside the outer exposed portion of the polishing belt, that is, the inner side of the polishing head 17 are provided. A roller 56b is rotatably mounted on the mounting member 57.

  The attachment member 57 is connected to a tension pressurization drive unit 59 with a pressure sensor 58 interposed therebetween, and the attachment member 57 is pushed toward the polishing belt 18 by the tension pressurization drive unit 59. Yes. Therefore, when the mounting member 57 is pressed toward the polishing belt 18, the upper tension pressure roller 56 a and the lower tension pressure roller 56 b move toward the polishing belt 18, and press the polishing belt 18 from the inside of the polishing head 17. And get nervous. Even in this pressed state, the upper tension pressure roller 56a and the lower tension pressure roller 56b are free rollers, and thus rotate when the polishing belt runs.

  The pressure sensor 58 is positioned between the upper tension pressure roller 56 a and the lower tension pressure roller 56 b and the tension pressure driving unit 59, and the tension pressure driving unit 59 moves in the direction of the wafer 12. A constant pressure is always applied to the notch portion of the wafer 12.

  As the polishing belt 18, a known endless polishing belt used for fixed abrasive polishing or loose abrasive polishing can be used. In the case of fixed abrasive polishing, one or more kinds selected from fine particles such as diamond, aluminum oxide, silica, cerium oxide on the surface of plastic, woven fabric sheet, non-woven fabric sheet, foam sheet, flocked sheet, etc. An endless polishing belt with single particles or composite particles in which an abrasive layer having abrasive grains fixed thereon is formed is used. In the case of free abrasive polishing, plastic, woven fabric sheet, non-woven fabric sheet, foam sheet, flocked sheet or the like is used as the endless polishing belt.

  In the case of fixed abrasive polishing, a cooling liquid is supplied to the semiconductor wafer 12 by the nozzle (not shown). In the case of loose abrasive polishing, polishing is performed by running a polishing belt. Sometimes, a polishing liquid in which abrasive grains are suspended in water or a water-based dispersion is supplied to the semiconductor wafer 12.

  Next, the operation of the semiconductor wafer notch end surface polishing apparatus according to the present invention will be described with reference to FIGS.

  As shown in FIG. 5, the slider 27 is moved to the polishing head side on the slide frame 28 with respect to the polishing head 17 placed in the horizontal state, and the notch 16 of the semiconductor wafer 12 placed on the wafer holding table 13 is obtained. Is brought into contact with the polishing belt 18.

  Then, the polishing belt running motor 32 is operated to run the polishing tape 18. At this time, the attachment member 57 is pressed toward the polishing belt by the tension pressing drive unit 59 in the polishing head 17, and the upper tension pressing roller 56 a and the lower tension pressing roller 56 b are connected from the polishing head 17 to the polishing belt 18. Press to tension.

  As shown in FIG. 9, the tensioned polishing belt 18 sufficiently contacts the notch end surface 61, the notch upper end surface 62, and the notch lower end surface 63 of the notch 16 portion of the semiconductor wafer 12 to be contacted. Mirror finish can be performed.

  Further, as shown in FIG. 6, the swinging arm 33 is rotated to tilt the polishing head 17 in a state where the polishing contact portion is on the lower side, thereby further contacting the notch upper end surface 62 shown in FIG. Therefore, the polishing of this part is further improved.

  Further, as shown in FIG. 7, the swinging arm 33 is rotated so that the polishing head 17 is tilted with the polishing contact portion on the upper side, thereby further contacting the notch lower end surface 63 shown in FIG. Therefore, the polishing of this part is further improved.

  Then, as shown in FIG. 8, the wafer swinging portion 22 is operated to rotate the semiconductor wafer 12 about the polishing contact portion on a horizontal plane, so that the left and right sides of the notch end surface shown in FIG. Since the contact can be made, the polishing of the notch end face is further improved.

  As described above, according to the semiconductor wafer notch end surface polishing apparatus according to the present invention, unlike the conventional polishing apparatus that rotates the disc-shaped polishing plate having the polishing pad fixed around, the polishing belt is brought into contact with the notch end surface portion. Since polishing is performed, the polishing effect of the end face is improved, and the accuracy of mirror finishing is also improved.

1 is a front view of a semiconductor wafer notch end surface polishing apparatus according to the present invention. FIG. The top view of the semiconductor wafer notch end surface grinding | polishing apparatus. 1 is a front view of a polishing head according to the present invention. FIG. 3 is a plan view of the polishing head. The front view which shows the operation state (horizontal position) of the polishing head. The front view which shows the operation state (inclination position which turned down the grinding | polishing contact part) of the grinding | polishing head. The front view which shows the operation state (inclination position which turned up the grinding | polishing contact part) of the grinding | polishing head. The top view which shows the rocking | swiveling (turning) state of a semiconductor wafer. The typical expansion perspective view of a semiconductor wafer notch end face.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Semiconductor wafer 13 Semiconductor wafer holding stand 15 Wafer rocking part 17 Polishing head 18 Polishing belt 33 Swing arm

Claims (7)

  A polishing head for polishing a notch end surface of a semiconductor wafer, which is hung on a driving roller that is rotated by a driving device, at least one free roller that can rotate, and the driving roller and the free roller. A polishing head comprising: an endless polishing belt that travels; and tension means that presses and tensions the polishing belt.   2. The polishing according to claim 1, wherein the tensioning unit includes a tension pressure roller that presses the polishing belt by sliding movement, and a pressure driving unit that slides the tension pressure roller. head.   The polishing head according to claim 2, wherein the tensioning unit further includes a pressure sensor.   5. The polishing head according to claim 1, and the polishing head in a state where the polishing belt travels on a vertical surface, the polishing head in which a semiconductor wafer notch and the polishing belt are in contact with each other. 2. A semiconductor wafer notch end surface polishing apparatus comprising: a polishing head swinging means for rotating on a vertical surface around a contact portion; and a semiconductor wafer holding table for holding the semiconductor wafer in a horizontal state.   Further, the semiconductor wafer swinging means for swinging the holding table in the horizontal direction is provided, and the semiconductor wafer holding table is polished by the semiconductor wafer swinging unit so that the semiconductor wafer notch and the polishing belt come into contact with each other. 5. The semiconductor wafer notch end surface polishing apparatus according to claim 4, wherein the semiconductor wafer notch end surface polishing apparatus rotates on a horizontal plane around the contact portion.   The semiconductor wafer swinging means includes a support leg for supporting the semiconductor wafer holding base, a holding base swinging arm having one end connected to a lower end portion of the support leg and extending in a horizontal direction, and the holding base swinging 6. The semiconductor wafer notch end surface polishing apparatus according to claim 5, further comprising a rotation shaft connected to the other end of the arm and a rotation shaft driving device for rotating the rotation shaft.   The rail further includes a rail on which the semiconductor wafer swinging means is mounted, and a slider that moves on and off the rail in a direction in which the semiconductor wafer swinging means comes into contact with the polishing belt. The semiconductor wafer notch end surface polishing apparatus according to claim 5 or 6.

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