JP2010221362A - Manufacturing method of disk shaped substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extend a life of a carrier used for manufacturing a disk shaped substrate. <P>SOLUTION: First in a secondary lapping process, as shown in (A), the carrier 30 in an unused state is initially mounted to a lower fixed disk 21a. A first thickness C1 of the carrier 30 in this embodiment can be set to, for instance, 0.55 mm. Then, as shown in (A), a work 10 is set in a hole 34 formed at the carrier 30. An initial thickness W1 of the work 10 is 0.70 mm. Then, an upper fixed disk, the lower fixed disk 21a and a sun gear are rotated to achieve the planetary movement of the carrier 30 and polish a surface 11 of the work 10 mounted in the hole part 34. Thus, as shown in (B), the thickness of the work 10 is reduced and the thickness of the work 10 is made to a finished thickness W2 (in this embodiment, 0.548 mm). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a disk-shaped substrate such as a glass substrate for a magnetic recording medium.

  In response to the increasing demand for recording media, the manufacture of disk substrates, which are disk-shaped substrates, has recently become active. As a magnetic disk substrate which is one of the disk substrates, an aluminum substrate and a glass substrate are widely used. This aluminum substrate is characterized by high workability and low cost, and one glass substrate is characterized by excellent strength, surface smoothness and flatness. In particular, recently, the demand for miniaturization and high density of the disk substrate has been remarkably increased, and the degree of attention of the glass substrate capable of achieving high density with small roughness of the surface of the substrate has increased.

  In the manufacturing process of such a disk-shaped substrate, the disk-shaped substrate is positioned inside the holding hole formed in the carrier, and then the front and back surfaces of the disk-shaped substrate are polished using the upper and lower surface plates. There is a case. Here, when a disk-shaped substrate is polished using a carrier, a carrier having a thickness smaller than the thickness of the disk-shaped substrate is generally used (see, for example, Patent Document 1).

JP 2000-198064 A

By the way, when polishing and grinding a disk-shaped substrate using a carrier, the carrier is gradually worn due to being placed in contact with the lower surface plate or the like, and the thickness gradually decreases. Then, for example, when a specified thickness is reached and the life is reached, the carrier is replaced with a new carrier. However, when the carrier replacement frequency increases, the productivity is adversely affected. On the other hand, it is possible to reduce the production cost by reducing the carrier replacement frequency.
An object of the present invention is to extend the life of a carrier used for manufacturing a disk-shaped substrate.

  For such a purpose, a method for manufacturing a disk-shaped substrate to which the present invention is applied includes placing a carrier on a lower polishing surface plate of a pair of upper and lower grinding surface plates, setting the disk-shaped substrate on the carrier, and A method of manufacturing a disk-shaped substrate in which the front and back surfaces are ground by a pair of grinding surface plates, wherein the initial thickness of the carrier is larger than the finished thickness of the disk-shaped substrate.

  Here, the initial thickness of the carrier may be smaller than the initial thickness of the disk-shaped substrate. The carrier may be characterized in that the base material is formed of a resin material.

  From another viewpoint, the disk-shaped substrate manufacturing method provided by the present invention is a disk-shaped substrate in which a carrier is placed on a lower polishing surface plate of a pair of upper and lower grinding surface plates, and the disk-shaped substrate is set on the carrier. A method of manufacturing a disk-shaped substrate in which the front and back surfaces of the disk are ground with a pair of grinding surface plates, and the disk is ground by grinding the disk-shaped substrate using a new carrier that is not used for grinding. The carrier is also ground to a thickness equivalent to the finished thickness of the substrate.

  Here, by setting the initial thickness of the carrier to be larger than the finishing thickness of the disc-shaped substrate, the grinding thickness of the disc-shaped substrate using the new carrier is equivalent to the finishing thickness of the disc-shaped substrate. The carrier can be ground to a thickness.

  The life of the carrier used for manufacturing the disk-shaped substrate can be extended as compared with the case where the present invention is not adopted.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIGS. 1-1 (a) to (d) and FIGS. 1-2 (e) to (h) are diagrams showing a manufacturing process of a disk-shaped substrate (disk substrate) to which the present embodiment is applied.

(Primary lapping process)
FIG. 1-1 (a) shows the primary lapping process. In this step, first, lapping is performed by the lapping machine 40, and the surface 11 of the workpiece 10 which is a raw material of the disk-shaped substrate is ground smoothly.

FIG. 2 is a diagram showing the structure of the wrapping machine 40.
The lapping machine 40 shown in FIG. 2 includes a lower surface plate 21a on which the workpiece 10 is placed, and an upper surface plate 21b that presses the workpiece 10 from above and applies pressure to wrap the workpiece 10. .
Here, the tooth part 42 is provided in the outer peripheral part of the lower surface plate 21a. A sun gear 44 is provided at the center of the lower surface plate 21a. Further, a disk-shaped carrier 30 for positioning the workpiece 10 when lapping is performed is installed on the lower surface plate 21a.
Five carriers 30 are installed in the lapping machine 40 shown in FIG. A tooth portion 32 is provided on the outer peripheral portion of the carrier 30, and the carrier 30 meshes with both the tooth portion 42 of the lower surface plate 21 a and the sun gear 44 via the tooth portion 32. Further, rotation shafts 46a and 46b for rotating the lower surface plate 21a and the upper surface plate 21b are provided at the center portions of the lower surface plate 21a and the upper surface plate 21b, respectively.

In this primary lapping step, the carrier 30 is first installed on the lower surface plate 21a of the wrapping machine 40. Next, the workpiece 10 is placed.
FIG. 3 is a diagram illustrating the carrier 30 in more detail. As described above, the carrier 30 shown in FIG. 3 is provided with the tooth portion 32 on the outer peripheral portion. Further, the carrier 30 has a plurality of circular holes 34 in which the workpiece 10 is placed when lapping is performed. The diameter of the hole 34 is slightly larger than the diameter of the workpiece 10. By setting it as such a form, when lapping is performed, it can suppress that extra stress is applied to a part of outer periphery end of the workpiece | work 10. FIG.

Here, in the present embodiment, the diameter of the hole 34 is, for example, about 1 mm larger than the diameter of the workpiece 10. Further, the holes 34 are arranged at almost equal intervals, and in the case of the present embodiment, for example, 35 holes 34 are provided. More specifically, the carrier 30 is provided with five hole portions 34 provided along the circumferential direction and arranged at equal intervals at a location closest to the center of the carrier 30. Further, twelve hole portions 34 are also provided on the outer peripheral side of these five hole portions 34 and are also provided along the circumferential direction and arranged at equal intervals. Further, 18 hole portions 34 provided along the circumferential direction and arranged at equal intervals are provided on the outer peripheral side of the twelve hole portions 34 (the outermost peripheral side of the carrier 30).
Although it does not specifically limit as a material of the carrier 30, For example, the epoxy resin reinforced by mixing an aramid fiber and glass fiber can be used.

Here, after the workpiece 10 is placed inside the hole 34 in the carrier 30, the upper surface plate 21 b is moved until it contacts the workpiece 10, and the lapping machine 40 is operated.
The operation of the wrapping machine 40 at this time will be described with reference to FIG. When the lapping machine 40 operates, the upper rotating shaft 46b in the drawing is rotated in one direction, and the upper surface plate 21b is rotated in the same one direction. Further, the lower rotating shaft 46a in the figure is rotated in the opposite direction to the rotation of the rotating shaft 46b, and the lower surface plate 21a is rotated in the same direction as the rotating shaft 46a. Thereby, the tooth part 42 of the lower surface plate 21a also rotates in the same direction as the rotating shaft 46a. The sun gear 44 at the center also rotates in the same direction as the rotation shaft 46a.

  Thus, by rotating the upper surface plate 21b, the lower surface plate 21a, and the sun gear 44, the carrier 30 meshing with these gears performs a so-called planetary motion in which a rotation motion and a revolution motion are combined. Similarly, the workpiece 10 placed inside the hole 34 in the carrier 30 also performs planetary motion. By using such a lapping machine 40, the workpiece 10 can be lapped more accurately and quickly.

  Note that lapping in this embodiment can be performed using an abrasive. The abrasive is not particularly limited, and for example, an abrasive made of alumina or diamond can be used in a slurry state. Moreover, you may provide the grindstone in which these abrasives were disperse | distributed and included in the upper surface plate 21b and the lower surface plate 21a.

(Inner and outer grinding process)
FIG. 1-1 (b) shows the inner and outer peripheral grinding steps. In this step, grinding that is roughing of the inner peripheral surface of the opening 12 of the workpiece 10 and the outer peripheral surface of the outer periphery 13 of the workpiece 10 is performed. In the present embodiment, the inner peripheral surface and the outer peripheral surface are simultaneously ground. Specifically, the opening 12 provided in the center of the workpiece 10 is ground by the inner peripheral grindstone 22, and the outer periphery 13 of the workpiece 10 is ground by the outer peripheral grindstone 23. At this time, the workpiece 10 is sandwiched between the inner peripheral grindstone 22 and the outer peripheral grindstone 23 and simultaneously processed. Thereby, it becomes easy to ensure the concentricity of the inner diameter and the outer diameter of the workpiece 10.

  Moreover, in this Embodiment, the surface shape of the inner periphery grindstone 22 and the outer periphery grindstone 23 is a waveform. In other words, the inner peripheral grindstone 22 and the outer peripheral grindstone 23 have convex portions that become peaks and concave portions that become valleys on the surfaces thereof. Here, a plurality of convex portions and concave portions are provided, and are alternately provided along the axial direction of the inner peripheral grindstone 22 and the outer peripheral grindstone 23. For this reason, in this embodiment, not only the inner peripheral surface of the opening 12 and the outer peripheral surface of the outer periphery 13 of the workpiece 10 can be ground, but also the chamfering of the edges in the opening 12 and the outer periphery 13 can be performed together. It becomes possible.

(Inner circumference polishing process)
FIG. 1-1 (c) shows the inner periphery polishing step. In this step, polishing is performed to further smooth the inner peripheral surface of the workpiece 10 that has been ground in the inner and outer peripheral grinding step shown in FIG.
Specifically, the workpieces 10 are first stacked and set on a holder (not shown). And the brush 24 is inserted in the opening 12 of the workpiece | work 10 set to this holder. Then, the brush 24 is rotated at a high speed while pouring the polishing liquid into the opening 12 of the workpiece 10. Thereby, the inner peripheral surface of the workpiece 10 is polished by the brush 24. In this embodiment, since the brush 24 is used in this way, the inner peripheral surface of the workpiece 10 can be polished, and the chamfered portion in the inner and outer peripheral grinding step can also be polished. As the polishing liquid, for example, a slurry obtained by dispersing cerium oxide abrasive grains in water can be used.

  Here, FIG. 4 is a diagram showing an example of the brush 24 used in the inner periphery polishing step. The brush 24 includes a brush portion 61 in which hair ends are arranged in a spiral shape, and a shaft 62 that is formed continuously at both ends of the brush portion 61 and forms one end and the other end. For example, when polishing the inner peripheral surface of a small-diameter disk such as 0.85 inch, it is necessary to make the core of the brush 24 thinner. Therefore, in the present embodiment, for example, between a plurality of wires (material: for example, a mild steel wire (SWRM), a hard steel wire (SWRH), a stainless steel wire (SUSW), a brass wire (BSW), etc.) The brush portion 61 is formed by sandwiching hair (material: nylon (trade name of DuPont, for example)) and twisting the wire in which the hair is sandwiched. Here, by twisting the wire to form the brush portion 61, the brush tip formed on the brush portion 61 can be spiral. In addition, by making the brush tip formed in the brush portion 61 spiral, the polishing liquid can flow in the axial direction through the opening 12 of the workpiece 10 to be inserted. As a result, the polishing liquid can be transported satisfactorily.

(Secondary lap process)
FIG. 1-1 (d) shows the secondary lapping process. In this step, the lapping is again performed on the surface 11 of the workpiece 10 that has been lapped in the primary lapping step shown in FIG.
In this secondary lapping process, the lapping machine 40 shown in FIG. 2 is used. Moreover, the workpiece | work 10 is mounted in each of the some hole 34 provided in the carrier 30 similarly to a primary lapping process. Then, by rotating the upper surface plate 21 b, the lower surface plate 21 a, and the sun gear 44, the carrier 30 is caused to perform a planetary motion, and the surface 11 of the work 10 placed in the hole 34 is polished. The secondary lap process will be described in further detail later.

(Outer periphery polishing process)
FIG. 1-2 (e) shows the outer periphery polishing step. In this step, polishing is performed to further smooth the outer peripheral surface of the workpiece 10 ground in the inner and outer peripheral grinding step shown in FIG. 1-1 (b).
Specifically, first, the workpiece 10 is stacked on the opening 12 portion of the workpiece 10 through the jig 25, and the workpiece 10 is set on the jig 25. Then, the brush 26 is brought into contact with the stacked workpieces 10 while being poured into the outer peripheral portion 13 of the workpiece 10 and rotated at a high speed. Thereby, the outer peripheral surface of the workpiece | work 10 can be grind | polished.
At this time, since the brush 26 is used for polishing, the outer peripheral surface of the workpiece 10 can be polished, and the chamfered portion in the inner and outer peripheral grinding step can also be polished. As the polishing liquid, as in the case of the inner peripheral polishing step, for example, a slurry obtained by dispersing cerium oxide abrasive grains in water can be used.

(Primary polishing process)
FIG. 1-2 (f) shows the primary polishing process. In this step, the surface 11 of the workpiece 10 lapped in the secondary lapping step shown in FIG. 1-1D is further polished by using a polishing machine 50 to increase the smoothness. . The polishing machine 50 has substantially the same configuration as the lapping machine 40 described above, but the materials used for polishing are partially different as shown below.
In this primary polishing step, for example, a hard polishing cloth formed of urethane is used. In this primary polishing step, cerium oxide abrasive grains dispersed in water and slurried can be used as an abrasive.

(Secondary polishing process)
FIG. 1-2 (g) shows the secondary polishing step. In this step, the surface 11 of the workpiece 10 polished in the primary polishing step shown in FIG. 1-2 (f) is further polished by precision polishing, and the surface 11 is finally finished.
In this secondary polishing step, for example, a suede-like soft polishing cloth is used. In the secondary polishing step, cerium oxide abrasive grains or colloidal silica dispersed in a solvent such as water and slurried can be used as an abrasive.

(Final cleaning / inspection process)
FIG. 1-2 (h) shows the final cleaning / inspection process. In the final cleaning, the abrasive used in the series of steps described above is removed. For the cleaning, a method such as chemical cleaning with a detergent (chemical) using ultrasonic waves can be used.
In the inspection process, for example, the surface of the workpiece 10 is inspected for scratches or distortions by an optical inspection device using a laser.

Here, the secondary lapping process shown in FIG. 1-1 (d) will be described in more detail.
In the secondary lapping process, as described above, the wrapping machine 40 shown in FIG. 2 is used. Moreover, the workpiece | work 10 is mounted in each of the some hole 34 provided in the carrier 30 (refer FIG. 3). Then, by rotating the upper surface plate 21b, the lower surface plate 21a, and the sun gear 44 (see FIG. 2), the carrier 30 is caused to perform a planetary motion, and the surface 11 of the workpiece 10 placed in the hole 34 is polished (ground). )

  Here, FIG. 5 is a figure for demonstrating a secondary lapping process. Specifically, a cross-sectional view of the carrier 30, the workpiece 10, and the lower surface plate 21a is shown. In addition, in this figure, illustration of the upper surface plate 21b (refer FIG. 2) is abbreviate | omitted.

  In this secondary lapping step, first, as shown in FIG. 5A, the carrier 30 that is not in use (not polished) is placed on the lower surface plate 21a. Here, the initial thickness C1 of the carrier 30 in the present embodiment employs, for example, 0.55 mm as a slightly larger value than a finishing thickness W2 (0.548 mm in this example) described later. Next, as shown in FIG. 3A, the workpiece 10 is set in the hole 34 formed in the carrier 30. Here, the initial thickness (thickness before the start of the secondary lap) W1 of the workpiece 10 in this embodiment is 0.70 mm, which is larger than the initial thickness C1 (= 0.55 mm) of the carrier 30. ing. In addition, the diameter of the workpiece | work 10 in this embodiment is 1.89 inches, for example.

Next, by rotating the upper surface plate 21 b, the lower surface plate 21 a, and the sun gear 44, the carrier 30 is caused to perform a planetary motion, and the surface 11 of the work 10 placed in the hole 34 is polished. Thereby, as shown to the same figure (B), the thickness of the workpiece | work 10 reduces, and the thickness of the workpiece | work 10 becomes the finishing thickness W2 (in this example, 0.548 mm).
Here, in the present embodiment, the initial thickness C1 of the carrier 30 is slightly larger than the finished thickness W2 of the workpiece 10. For this reason, as shown in FIG. 5B, the carrier 30 is also scraped when the workpiece 10 is lapped. When the lapping of the first batch (first time) is completed, the carrier 30 has a thickness C2 (about 0.548 mm) equivalent to the finished thickness W2 of the workpiece 10.

  Thereafter, the work 10 in the state of FIG. 5B is removed from the carrier 30 and the second batch (second time) is lapped. Specifically, the work 10 that has finished the first lapping is removed from the carrier 30, and a new work 10 that has not been subjected to the secondary lapping is placed in the hole 34 of the carrier 30, and the second batch of lapping is performed. . As described above, the lapping of the second batch does not mean that lapping is performed again on the same workpiece 10, but does mean that lapping is performed on another new workpiece 10.

Here, FIG. 5C shows a state before the new workpiece 10 is set and lapping of the second batch is performed.
Here, the thickness of the carrier 30 is reduced by the first batch of lapping as described above, and the thickness is C2. On the other hand, since the new workpiece 10 is not subjected to secondary wrapping, the thickness is not reduced, and the thickness is the initial thickness W1 (= 0.70 mm).
Thereafter, in the same manner as described above, by rotating the upper surface plate 21b, the lower surface plate 21a, and the sun gear 44, the carrier 30 moves in a planetary motion, and the surface 11 of the new workpiece 10 set in the hole 34 is polished. . As a result, the thickness of the workpiece 10 is reduced as shown in FIG. 4D to a finished thickness W2 (= 0.548 mm). Further, the carrier 30 is also shaved by the lower surface plate 21a to further reduce the thickness, and the thickness becomes C3 smaller than the thickness C2.

  Next, in the present embodiment, after the second lap of the second batch is completed, the workpiece 10 is removed from the hole 34 of the carrier 30 and a new workpiece 10 is set in the hole 34. Thereafter, the second lap of the third batch is performed. Further, after the third batch is completed, the removal of the workpiece 10 and the installation of a new workpiece 10 are repeated, and the secondary lap with respect to the workpiece 10 is performed. In addition, when the secondary lap is repeatedly performed in this manner, the carrier 30 is gradually thinned and the carrier 30 may be broken. Therefore, in the present embodiment, when the minimum thickness (the thickness of the thinnest portion) in the carrier 30 reaches the specified thickness, the carrier 30 is replaced with a new carrier 30.

By the way, as described above, the inventor makes the initial thickness C1 of the carrier 30 larger than the finished thickness W2 of the workpiece 10 and scrapes the carrier 30 together with the workpiece 10 when lapping the first batch. It has been found that the lifetime of 30 is doubled.
Conventionally, the present inventor uses a carrier 30 having an initial thickness C0 smaller than the finished thickness W2 (= 0.548 mm) of the workpiece 10 as shown in FIG. 6 (a diagram for explaining a conventional process). The first batch of wrapping was started. In this case, the carrier 30 has reached the end of its life in approximately 30 batches. That is, when reaching about 30 batches, the minimum thickness of the carrier 30 reached the specified thickness.

  On the other hand, as described above, when the initial thickness C1 of the carrier 30 is larger than the finished thickness W2 of the workpiece 10, the life of the carrier 30 is about 60 batches. Further, it is possible to increase the pressure applied to the workpiece 10 from the upper surface plate 21b and the lower surface plate 21a, and to increase the rotational speed of the upper surface plate 21b and the like. That is, even if lapping is performed after increasing the pressure acting on the workpiece 10 and the rotational speed of the upper surface plate 21b, it has been found that the life of the carrier 30 is extended rather than shortened by 30 batches. .

  Here, the reason why the life of the carrier 30 is increased is that the thickness of the carrier 30 is made uniform when lapping of the first batch is performed. The carrier 30 in the unused state has a thickness that is not necessarily uniform over the entire region, and may be partially thick or thin. When lapping is started in such a state, for example, deformation (for example, bending) is likely to occur in a thin portion, and this portion is considered to be particularly easily cut.

  In the embodiment shown in FIG. 6, since the carrier 30 is in contact with the lower surface plate 21a, the surface on the lower surface plate 21a side is smooth, but does not contact the upper surface plate 21b so much and is on the upper surface plate 21b side. The surface is difficult to be smooth. Even if contact is made, in this case, the carrier 30 may be scraped unevenly by the upper surface plate 21b. That is, in the embodiment shown in FIG. 6, the carrier 30 is not likely to have a uniform thickness, and there is a high possibility that a portion with a small thickness will remain. As a result, as described above, it is considered that deformation is likely to occur in a portion having a small thickness, and this portion is considered to be particularly easily cut. On the other hand, in the present embodiment, the upper surface of the carrier 30 is surely shaved by the upper surface plate 21b. For this reason, it is considered that the thickness can be made uniform and the above deformation can be suppressed.

  In the aspect in the present embodiment, the carrier 30 is sharpened more than in the aspect shown in FIG. 6, and there is a concern that the life of a grindstone (not shown) provided on the upper surface plate 21b may be shortened, for example. . However, the carrier 30 in the present embodiment has a base material formed of a resin material (epoxy resin) and is easy to scrape, and thus the life of such a grindstone has not been shortened. In addition, there was no particular change in the workpiece 10, and there was no problem caused by increasing the thickness of the workpiece 30.

Further, the initial thickness C1 of the carrier 30 shown in FIG. 5A may be larger than the initial thickness W1 of the workpiece 10. However, the carrier 30 becomes expensive as the thickness increases. In addition, the carrier 30 is shaved before lapping of the workpiece 10 is started, resulting in waste. For this reason, it is preferable that the initial thickness C1 of the carrier 30 be smaller than the initial thickness W1 of the workpiece 10.
In the present embodiment, the example in which the initial thickness C1 of the carrier 30 is larger than the finished thickness W2 of the workpiece 10 in the secondary lapping process has been described. For example, the primary lapping process and the primary polishing process described above. Similarly, in the secondary polishing step, the initial thickness C1 of the carrier 30 can be made larger than the finished thickness W2 of the workpiece 10.

It is the figure which showed the manufacturing process of the disk shaped board | substrate (disk board | substrate). It is the figure which showed the manufacturing process of the disk shaped board | substrate (disk board | substrate). It is the figure which showed the structure of the wrapping machine. It is a figure for demonstrating a carrier. It is the figure which showed an example of the brush used in an inner periphery grinding | polishing process. It is a figure for demonstrating a secondary lapping process. It is a figure explaining the conventional process.

10 ... Workpiece, 21a ... Lower surface plate, 21b ... Upper surface plate, 30 ... Carrier, 40 ... Lapping machine

Claims (5)

A disk in which a carrier is placed on the lower polishing surface plate of a pair of upper and lower grinding surface plates, a disk-shaped substrate is set on the carrier, and the front and back surfaces of the disk-shaped substrate are ground by the pair of grinding surface plates. A method for manufacturing a substrate,
A method for manufacturing a disk-shaped substrate, wherein an initial thickness of the carrier is larger than a finished thickness of the disk-shaped substrate.   2. The method for manufacturing a disk-shaped substrate according to claim 1, wherein an initial thickness of the carrier is smaller than an initial thickness of the disk-shaped substrate.   The method for manufacturing a disk-shaped substrate according to claim 1, wherein the carrier has a base material formed of a resin material. A disk in which a carrier is placed on the lower polishing surface plate of a pair of upper and lower grinding surface plates, a disk-shaped substrate is set on the carrier, and the front and back surfaces of the disk-shaped substrate are ground by the pair of grinding surface plates. A method for manufacturing a substrate,
A method for manufacturing a disk-shaped substrate, characterized in that the carrier is also ground to a thickness equivalent to a finished thickness of the disk-shaped substrate in grinding of the disk-shaped substrate using a new carrier not used for grinding.   By setting the initial thickness of the carrier to be larger than the finishing thickness of the disk-shaped substrate, the grinding of the disk-shaped substrate using the new carrier has a thickness equivalent to the finishing thickness of the disk-shaped substrate. 5. The method for manufacturing a disk-shaped substrate according to claim 4, wherein the carrier is ground.

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