JP2009028843A - Polishing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable polishing apparatus capable of reducing damage to a carrier, and improving productivity in polishing work and manufacturing yield. <P>SOLUTION: This polishing apparatus has a lower surface plate 31, an upper surface plate 21 formed oppositely to the lower surface plate, and a lifter 13 moving up and down the upper surface plate. Each workpiece is stored in each workpiece holding section 34a of the carrier 34. The carrier 34 is arranged on the upper surface of the lower surface plate, and is so arranged that a gear formed around the periphery of the carrier is engaged with a sun gear 32a made of polyurethane and an internal gear 33. Normally, a plurality of carriers 34 is arranged on the lower surface plate to polish a plurality of workpieces. After the carrier 34 is arranged, the upper surface plate 21 is moved down by the lifter 13. Thereby, the upper surface plate abuts on the carrier, and load by the upper surface plate is applied to the workpiece or the like. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing apparatus for polishing crystal, semiconductor material and the like.

  For example, a quartz diaphragm used for a quartz vibrating device can be obtained from an artificial quartz through a cutting process and a polishing process. In the polishing step, parallel plane polishing is performed using a pair of surface plates (upper and lower surface plates) having polishing surfaces on opposite sides, and a work (quartz vibration plate) is interposed between the surface plates. In this state, a polishing liquid composed of a liquid containing abrasive grains is appropriately supplied, and the work is polished by moving the work relative to the surface plate.

  The work is held by the carrier. One or a plurality of work holding portions are formed on the carrier, and a gear is formed on the outer periphery thereof. A sun gear and an internal gear are arranged at a height position corresponding to between the surface plates, and the carrier is arranged between the sun gear and the internal gear. The carrier rotates in a planetary manner by the configuration in which the gear of the carrier, the sun gear, and the internal gear mesh with each other, whereby the workpiece is planarly polished by the polishing liquid supplied to the surface plate.

  By the way, when an AT-cut quartz diaphragm is used as a workpiece, due to the recent demand for higher frequency, the plate thickness has become extremely thin, and therefore the carrier for holding it has also become extremely thin. Such thinning also affects the strength of the carrier, and the carrier may be damaged at the meshing portion with the sun gear or the internal gear.

Specifically, for example, the carrier is a metal material such as SK4, and the sun gear and the internal gear are made of chromium molybdenum steel such as SCM415. As described above, the carrier is considerably thinner than the sun gear and the internal gear in response to the thinning of the crystal diaphragm, so the carrier rotates with the carrier gear meshing with a part of the side surface of the sun gear or the internal gear. . This difference in thickness may cause the carrier to scratch the side of the sun gear or the like. Further, the scratches are likely to occur due to the presence of an abrasive used for polishing. When the carrier gear is caught in such a scratch, the carrier may be deformed or damaged. The breakage of the carrier also breaks the work held by the carrier, resulting in a decrease in manufacturing efficiency and a decrease in manufacturing yield in the polishing operation.

In particular, the sun gear has a smaller curvature than the internal gear, and the number of gears that mesh with the carrier is also reduced. For this reason, in the part meshing with the sun gear, the stress applied to one gear of the carrier is large, so that the carrier is easily damaged.
JP-A-5-305995

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a highly reliable polishing apparatus capable of reducing carrier breakage, improving productivity in polishing work, and improving manufacturing yield. It is what.

The present invention pays attention to the fact that the carrier breakage is caused by scratches formed in the sun gear during the polishing operation. The constituent material of the sun gear is examined, and a polishing apparatus having the structure as shown in claim 1 is provided. It is a feature.

That is, the upper surface plate and the lower surface plate with the polishing surfaces opposed to each other, the polishing liquid supplied between the surface plates, and the work surface holding portion and the gear on the outer periphery are disposed between the surface plates. A carrier, a workpiece housed in the workpiece holding portion, and a sun gear and an internal gear meshing with the carrier, and the carrier rotates in a planetary manner by the rotation of the sun gear and the internal gear. A polishing apparatus for polishing between boards, wherein at least the sun gear is made of a urethane resin material.

The sun gear (sun gear) is a gear that becomes the center of rotation, and is disposed inside (center side) of the polishing region. Further, the internal gear (inner peripheral gear) has a ring-like configuration arranged on the outer side of the sun gear and on the outer periphery of the polishing region, and the gear faces the inner side (sun gear side). The carrier is a planetary gear, and the rotation of the sun gear and the internal gear causes the carrier to mesh with the rotation of the sun gear (sun gear), which is the center of rotation, and simultaneously rotate around the sun gear (planetary rotation operation). I do. In such a carrier operation, the work held by the carrier is polished between the upper and lower surface plates. The polishing liquid is obtained by dissolving abrasive grains in a solvent, and the size (particle diameter) of the polishing powder is appropriately selected according to the polishing stage.

As described above, the sun gear is a gear that serves as the center of rotation of the polishing apparatus, and at least meshed teeth are made of urethane resin. Urethane resin is excellent in elasticity and extremely excellent in wear resistance. Accordingly, the sun gear is not easily worn even in an environment where the polishing liquid is present, so that the function of the sun gear is hardly reduced, contributing to the improvement of the reliability of the polishing apparatus.

Even if a carrier thinner than the sun gear meshes with the side of the gear of the sun gear, the side is not easily scratched.Therefore, unnecessary stress on the carrier is caused by local catching with the gear of the carrier due to this scratch. I will not let you.

Even if the scratches of the sun gear and the carrier gear are unnecessarily caught, the stress on the carrier can be relieved by the elasticity and flexibility of the urethane resin, and the carrier can be prevented from being damaged.

For example, polyurethane can be cited as an example of the urethane resin, but it can be applied to a urethane resin having excellent wear resistance and elasticity.

Further, in addition to the sun gear, an internal gear (inner peripheral gear) may be applied with urethane resin. In this case, the excellent wear resistance of the urethane resin suppresses the deterioration of the internal gear function, and further the carrier. This can further contribute to improving the reliability of the polishing apparatus.

  According to the present invention, it is possible to obtain a highly reliable polishing apparatus capable of reducing carrier breakage, improving productivity in polishing work, and improving manufacturing yield.

  Embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a polishing apparatus, and FIG. 2 is a perspective view of a sun gear.

  As shown in FIG. 1, the polishing apparatus includes a lower surface plate 31, an upper surface plate 21 that is formed to face the lower surface plate, and a lifting device 13 that raises and lowers the upper surface plate. FIG. 1 shows a state where the upper surface plate 21 is separated from the lower surface plate 31 and a carrier or the like located between both surface plates appears.

  In the polishing apparatus, an upright arm 11 extends upward, and a lateral arm 12 is attached to an upper portion of the upright arm 11. The horizontal arm 12 extends in a substantially horizontal direction from the attachment portion and extends to the upper part of the lower surface plate installation area described later. A lifting device 13 is attached to the distal end portion of the lateral arm 12. The elevating device 13 is composed of, for example, an air cylinder, and can move an upper surface plate, which will be described later, vertically. A holding portion 14 is provided below the lifting device 13. The holding portion 14 operates in response to the vertical movement by the lifting device, and moves the upper surface plate up and down together with holding or releasing the upper surface plate.

  The upper surface plate 21 that moves up and down by the elevating device is made of a metal body such as cast iron or stainless steel, and has a disk shape having a through hole in the center, that is, a donut-like shape. A plurality of holding bars 23 are provided upright on the upper surface of the upper surface plate, and a supply ring 22 is formed above the holding bar 23. The supply ring 22 has a ring-shaped groove opened upward, and has a configuration in which a polishing liquid described later accumulates in the groove. A connecting portion connected to the holding portion 14 passes through the penetrating portion at the center of the ring. Further, the supply ring 22 is connected to the second supply pipe 24 by a tube 25 so that the polishing liquid is supplied from the second supply pipe 24 into the upper surface plate.

  Although not shown in the upper surface plate, the upper surface plate has a plurality of upper and lower through holes, and the polishing liquid leaks to the polishing surface (the lower surface of the upper surface plate). Further, a predetermined shallow groove is formed on the polishing surface, and the leaked polishing liquid is spread over the entire polishing surface.

  The polishing apparatus has a polishing liquid supply device 41. The polishing liquid is used for polishing workpieces.For example, it consists of a liquid containing abrasives such as Green Silicon Carbide, White Fused Alumina, Emery, Celox, etc. and rust preventives. It selects suitably by the process to perform. Normally, a plurality of polishing steps are performed, but the polishing accuracy is improved by gradually reducing the abrasive grain size for each step. The polishing liquid supply device constantly agitates the polishing liquid and supplies a predetermined amount to the supply ring 22. Specifically, the polishing liquid of the polishing liquid supply apparatus 41 is guided to the first supply pipe 43 provided on the supply ring via the tube 42 and dropped from the first supply pipe 43 into the groove of the supply ring 22. .

  The lower surface plate 31 located below the upper surface plate has a disk shape made of a metal body such as cast iron or stainless steel, and has a through hole in the central portion and a flat surface on the upper surface (polishing surface). ing. A plurality of carriers 34 are arranged on the upper surface. The carrier 34 has a thin disk shape, and a gear (not shown) is formed on the outer periphery thereof. A plurality of through holes are formed in the carrier to form a work holding part.

A carrier having a thickness smaller than that of the workpiece is used. In the lower surface plate 31, a driving portion 32 protruding from the polishing apparatus main body is disposed in the through hole in the central portion. The drive unit 32 is provided with a sun gear 32a at the same height as the carrier, forms a rotation center, and meshes with the gear of the carrier 34. Further, an internal gear 33 independent of the lower surface plate is disposed in the outer peripheral upper region of the lower surface plate. The internal gear has a ring-like configuration in which a gear is formed on the inner side, and the internal gear 33 and the carrier gear mesh with each other.

  Further, the thickness of the sun gear 32a and the internal gear 33 is sufficiently thick with respect to the thickness of the carrier 34, and the carrier 34 is engaged with a portion other than the end of the thickness of the sun gear 32a or the internal gear 33. It has become.

  As shown in FIG. 2, the sun gear 32a has a through hole 32a1 formed at the center. This through-hole 32a1 portion is fitted into the drive unit 32 of the polishing apparatus, and operates as the rotation center of the polishing apparatus according to the rotation operation of the drive unit 32. The gear portion on the outer periphery of the sun gear is set to a pitch that can mesh with the carrier 34.

  In the present invention, the sun gear 32a is made of a urethane resin made of polyurethane. Urethane resin is excellent in elasticity and extremely excellent in wear resistance. In particular, polyurethane is excellent in elasticity and wear resistance. Therefore, since the sun gear is not easily worn even in an environment where a polishing liquid is present, the function of the sun gear is hardly reduced, and the reliability of the polishing apparatus is improved. Even if the carrier thinner than the sun gear meshes with the gear side surface of the sun gear, the side surface is not easily scratched.Therefore, the carrier is deformed or damaged due to local catching with the carrier gear caused by the scratch. Unnecessary stress is not generated.

Even if the scratches of the sun gear and the carrier gear are unnecessarily caught, the stress on the carrier can be relieved by the elasticity and flexibility of the urethane resin, and the carrier can be prevented from being damaged.

  The upper surface plate 21 has one or a plurality of small through holes, and the second supply pipe 24 is inserted into the small through holes. With such a configuration, the polishing liquid supplied from the second supply pipe leaks to the polishing surface through the minute through hole.

― Explanation of operation of polishing machine ―
Next, the operation of the polishing apparatus will be described by exemplifying the polishing of the quartz diaphragm.
Each workpiece (quartz vibration plate as an object to be polished) is accommodated in each workpiece holding portion 34a of the carrier. The carrier 34 is installed on the upper surface of the lower surface plate, and is arranged so that gears (not shown) on the outer periphery of the carrier mesh with the sun gear 32a and the internal gear 33, respectively. Usually, a plurality of carriers 34 are installed on the lower surface plate and perform polishing on a plurality of workpieces. After arranging the carrier 34, the upper surface plate 21 is lowered by the elevating device 13, whereby the upper surface plate is brought into contact with the carrier, and a load by the upper surface plate is applied to the workpiece or the like. In FIG. 1, a load is applied to the workpiece as the upper surface plate 21 descends to the carrier 34.

In this state, the sun gear 32a and the internal gear 33 of the drive unit are rotated. The rotation direction is the same for both the sun gear and the internal gear. However, the planetary rotational force is applied to the carrier due to the difference in gear ratio, and the work held by the rotating carrier is polished between the upper and lower surface plates.

The rotational drive configuration is a configuration in which the upper surface plate and the lower surface plate are fixed and only the carrier is rotated. In addition to the rotational drive, a rotational force may be applied to either the upper surface plate or the lower surface plate. Alternatively, more efficient polishing can be performed by applying a rotational force to both the upper surface plate and the lower surface plate in addition to the rotational drive. In addition, what is necessary is just to reverse both rotation direction, when giving rotational force to both an upper surface plate and a lower surface plate.

The polishing liquid is supplied from the polishing liquid supply device 41 to the first supply pipe 43 via the tube 42. From the first supply pipe 43, the polishing liquid is intermittently dropped onto the supply ring 22 and supplied from the supply ring 22 to the second supply pipe 24 through the tube 25. Further, the polishing liquid is supplied into the upper surface plate from the second supply pipe, and as described above, the polishing liquid leaks to the polishing surface through the plurality of upper and lower through holes provided in the upper surface plate. Yes. Further, a predetermined shallow groove is formed on the polishing surface, and the leaked polishing liquid is spread over the entire polishing surface.

  With the above configuration, while supplying an appropriate amount of polishing liquid to the polishing surface of the surface plate, the carrier is rotated to perform parallel plane polishing using the upper and lower surface plates. The time required for polishing, the rotation speed of the carrier, and the like are appropriately adjusted depending on the material of the abrasive grains used in the polishing liquid, the size, the load applied to the workpiece, and the like.

In the above-described embodiment, the constituent material of the sun gear 32a is characteristic, and urethane resin having excellent elasticity and excellent wear resistance is used. Since the gear part is made of urethane resin, it is flexible, and even if the sun gear and the carrier gear are unnecessarily caught and the carrier is deformed or stress concentrated, the elasticity and flexibility of the urethane resin Due to the properties, stress on the carrier can be relaxed and damage to the carrier can be prevented.

Next, a comparative example of a carrier breakage accident when using a conventional sun gear made of molybdenum steel and using a sun gear made of urethane resin is shown. The polishing apparatus used for the comparison is a 4B size polishing apparatus, and has a configuration having six carriers. The material of the carrier is a metal material equivalent to SK4, and the tip diameter is 104 mm, and the thickness is 0.036 mm. The thickness of the carrier is generally determined by the thickness of the workpiece such as a crystal diaphragm. The sun gear and the internal gear each have a thickness of 20 mm, which is much larger than the carrier. The diameter of the tip circle of the sun gear is 128 mm, and the diameter of the tip circle of the internal gear is 320 mm. The polishing liquid used here is a WA # 4000 size abrasive.

In the polishing apparatus configured as described above, the work (quartz vibration plate) was polished for the conventional polishing apparatus in which the sun gear is made of molybdenum steel of SCM415 and the polishing apparatus of the present invention using polyurethane resin. . When a normal polishing operation for about one month was performed, two sets (total of 12 sheets) of carrier damage accidents occurred in the conventional configuration, whereas no carrier damage accident occurred in the configuration of the present invention. In addition, the durability of the sun gear itself has been greatly improved, and the replacement frequency has been greatly extended. From the above verification results, it can be understood that the present invention is extremely effective in practice, and a highly reliable polishing apparatus that can reduce carrier breakage, improve productivity in polishing work, and improve manufacturing yield. Can be obtained.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit, gist, or main features. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention is suitable for a polishing apparatus for polishing crystal, semiconductor material and the like.

It is a schematic perspective view of a grinding | polishing apparatus. It is a perspective view of a sun gear.

Explanation of symbols

21 Upper surface plate 31 Lower surface plate 32 Drive part 32a Sun gear 33 Internal gear 34 Carrier

Claims (1)

An upper surface plate and a lower surface plate, the polishing surfaces being opposed to each other, a polishing liquid supplied between the surface plates, a carrier disposed between the surface plates, having a work holding unit and having a gear on the outer periphery. A workpiece housed in the workpiece holding portion, and a sun gear and an internal gear meshing with the carrier, and the carrier rotates in a planetary manner by the rotation of the sun gear and the internal gear. A polishing apparatus for polishing with
At least the sun gear is made of a urethane resin material.

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