JP4527559B2 - Exposure equipment - Google Patents

Description

  The present invention relates to an exposure apparatus that exposes a resist film coated on a back surface or a front surface of a wafer having functional elements formed in regions partitioned by grid-like division lines on the surface along the division lines.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets formed in a lattice shape on the surface of a substantially disc-shaped semiconductor wafer, and functions such as IC and LSI are defined in the partitioned regions. An element is formed. Then, by cutting the semiconductor wafer along the planned dividing line, the region where the functional element is formed is divided to manufacture individual semiconductor chips. In addition, an optical device wafer in which a light emitting element (functional element) such as a gallium nitride compound semiconductor is laminated on the surface of a sapphire substrate is cut along a predetermined division line so that light from each light emitting diode, laser diode, etc. Divided into devices and widely used in electrical equipment.

The cutting along the division lines such as the above-described semiconductor wafer and optical device wafer is usually performed by a cutting device called a dicer. The cutting apparatus is configured to move a chuck table that holds a workpiece, a cutting unit that includes a cutting blade for cutting the workpiece held on the chuck table, and the chuck table and the cutting unit. The wafer is cut along the street by feeding the chuck table holding the workpiece while rotating the cutting blade. (For example, refer to Patent Document 1.)
JP 2001-85365 A

  However, when the wafer is cut by the cutting blade of the above-described cutting apparatus, fine chips are likely to occur on the outer periphery of each divided chip, which causes a reduction in the bending strength of the chip. In order to solve such a problem, a resist film is coated on the back surface of the wafer, and a region corresponding to the planned dividing line of the resist film is developed and removed by exposure. Thereafter, the wafer is removed from the resist film side. There has been proposed a method of dividing a wafer along a planned division line by etching along the planned division line by plasma etching or the like.

  Thus, in the exposure process for exposing the region corresponding to the planned division line of the resist film coated on the back surface of the wafer, it is necessary to prepare a mask member corresponding to the planned division line formed on the wafer. The mask member must be manufactured each time for wafers with different intervals between the lines to be divided, which is not always satisfactory in terms of productivity.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to provide an exposure apparatus capable of exposing a wafer having different intervals between division scheduled lines without producing a mask member each time. There is.

In order to solve the above-mentioned main technical problem, according to the present invention, a resist film coated on the back surface or the surface of a wafer in which functional elements are formed in a region partitioned by lattice-like division lines on the surface is divided. An exposure apparatus that performs exposure along a planned line,
A plurality of chuck tables holding wafers;
Alignment means for detecting division planned lines formed on the wafer respectively held by the plurality of chuck tables;
Slit exposure means for exposing slit light corresponding to the division lines to the resist film coated on the back surface or the front surface of the wafer respectively held by the plurality of chuck tables;
Index means for relatively moving the plurality of chuck tables and the slit exposure means and positioning the division lines formed on the wafers respectively held by the plurality of chuck tables at the exposure position of the slit light; Has
An exposure apparatus is provided.

  The slit exposure unit includes a mask unit having at least one slit and a light emitting unit that exposes slit light through the slit of the mask unit. The mask means preferably includes a plurality of slits, and further includes an interval adjusting means for adjusting an interval between the plurality of slits. The index means moves a plurality of chuck tables in a direction perpendicular to the slits of the mask means, and positions a division line that extends in a predetermined direction formed on a wafer held by the plurality of chuck tables at an exposure position of the slit light. The index dividing means and the plurality of chuck tables are rotated to position the planned dividing line in the direction orthogonal to the predetermined dividing line extending in a predetermined direction formed on the wafer held on the chuck table in parallel with the slit of the mask means. It consists of rotating means.

  In the exposure apparatus according to the present invention, the plurality of chuck tables are moved by the index means, and the division lines formed on the wafers respectively held by the plurality of chuck tables are positioned at the exposure position of the slit light. Therefore, it is not necessary to manufacture wafers with different intervals between the lines to be divided each time, and a plurality of wafers can be exposed at the same time, thereby improving productivity.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of an exposure apparatus constructed according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of an exposure apparatus constructed according to the present invention. The exposure apparatus in the illustrated embodiment includes a base 2, a plurality of (two in the illustrated embodiment) chuck tables 3 and 3 that hold wafers, which will be described later, and two bases disposed on the base 2. Two index means 4 and 4 for supporting the chuck table, an alignment means 5 for detecting a division line formed on a wafer to be described later held on the two chuck tables 3 and 3 respectively, and two pieces Slit exposure means 6 for exposing slit light to the wafer held on the chuck tables 3 and 3 is provided.

The two chuck tables 3, 3 and the two index means 4, 4 will be described with reference to FIG. Since the two chuck tables 3 and 3 and the two index means 4 and 4 have the same configuration, only one symbol will be described below.
Each chuck table 3 includes a suction chuck 31 formed of a porous material, and holds a wafer described later on the suction chuck 31 by suction means (not shown). The chuck table 3 is adapted to be moved in the indexing feed direction indicated by the arrow Y in FIGS. 1 and 2 by the index means 4 and is configured to be rotatable.

  The index means 4 includes a pair of guide rails 41 and 41 arranged in parallel along the indexing feed direction indicated by the arrow Y on the base 2 (see FIG. 1), and the arrow Y on the guide rails 41 and 41. A support base 42 movably disposed in the indexing and feeding direction shown by FIG. 2, a cylindrical member 43 disposed on the support base 42 and rotatably supporting the chuck table 3, and disposed in the cylindrical member 43. And a pulse motor 44 as a rotating means for rotating the chuck table 3 and an index feed means 45 for moving the support base 42 along the pair of guide rails 41, 41 in the index feed direction indicated by the arrow Y. is doing.

  The support base 42 is provided with a pair of guided grooves 421 and 421 that are fitted to the pair of guide rails 41 and 41 on the lower surface thereof, and the guided grooves 421 and 421 are formed into the pair of guide rails 41 and 41. By fitting, it is configured to be movable along the pair of guide rails 41, 41 in the indexing feed direction indicated by the arrow Y. The pulse motor 44 as the rotation means can rotate the chuck table 3 at every predetermined angle. The index feeding means 45 includes a male screw rod 451 disposed in parallel between the pair of guide rails 41 and 41, and a drive source such as a pulse motor 452 for rotating the male screw rod 451. . One end of the male screw rod 451 is rotatably supported by a bearing block 453 fixed to the base 2, and the other end is connected to the output shaft of the pulse motor 452. The male screw rod 451 is screwed into a through female screw hole 423a formed in a female screw block 423 provided to protrude from the lower surface of the center portion of the support base 42. Accordingly, when the male screw rod 451 is driven to rotate forward and reversely by the pulse motor 452, the support base 42 is moved along the guide rails 41 and 41 in the index feed direction indicated by the arrow Y.

  Returning to FIG. 1 and continuing the description, the alignment means 5 is disposed above one end of the pair of guide rails 41, 41 constituting the index means 4. In the illustrated embodiment, the alignment unit 5 includes, in addition to a normal image sensor (CCD) that captures an image with visible light, an infrared illumination unit that irradiates a workpiece with infrared rays, and an infrared ray that is irradiated by the infrared illumination units. And an image pickup means 51 composed of an image pickup device (infrared CCD) that outputs an electrical signal corresponding to the infrared ray captured by the optical system, and the image pickup means 51 captures an image signal Is sent to control means (not shown). The imaging means 51 is supported by a support member 53 mounted on a support column 52 erected on the base 2 via a support arm 54. The support arm 54 to which the imaging means 51 is attached is moved in a direction indicated by an arrow X in FIG. 1, that is, a direction orthogonal to the index feed direction indicated by the arrow Y by a moving means (not shown) disposed in the support member. It is configured to be moved.

  Next, the slit exposure means 6 will be described. The slit exposure unit 6 in the illustrated embodiment includes a mask unit 61 and a light emitting unit 62. The mask means 61 is formed by an upper wall 611, a left side wall 612, a right side wall 613, and a front end wall 614, and is disposed on the base 2 so as to cover the alignment means 5. The upper wall 611 of the mask means 61 is provided with one slit 611a in the direction orthogonal to the index feed direction indicated by the arrow Y in the illustrated embodiment. The chuck table 3 can move along the pair of guide rails 41 and 41 in the mask means 61 configured as described above. The light emitting means 62 constituting the slit exposure means 6 is supported by a support column 63 erected on the base 2, and is disposed above the slit 611 a formed in the upper wall 611 of the mask means 61. Then, predetermined light is irradiated toward the slit 611a.

The exposure apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
Here, a wafer as a workpiece to be exposed by the exposure apparatus will be described with reference to FIG. A wafer 10 shown in FIG. 7 is made of a silicon wafer, and is formed in a lattice shape on a surface 10a by a plurality of division lines 101 parallel to each other. On the surface 10 a of the wafer 10, circuits 102 as functional elements are formed in a plurality of regions partitioned by a plurality of division lines 101. The wafer 10 configured as described above has a back surface ground and a thickness of, for example, 100 μm. In order to etch the wafer 10 along the planned dividing line 101 and divide it into individual chips, a photosensitive resist film 11 is formed on the back surface 10b of the wafer 10 as shown in FIG. 8 (resist film forming step).

Next, an exposure process is performed in which the photosensitive resist film 11 formed on the back surface 10b of the wafer 10 by the above-described resist film forming process is exposed along the planned division line 101, and an area corresponding to the planned division line 101 is removed. To do.
In the exposure process, first, the surface 10a side of the wafer 10 is placed on the two chuck tables 3 and 3 of the exposure apparatus, respectively, and a suction means (not shown) is operated to place the wafer 10 on the two chuck tables 3 and 3. The wafers 10 and 10 are sucked and held respectively. Accordingly, the photosensitive resist film 11 formed on the back surface 10b of each of the wafers 10 and 10 is on the upper side. In this way, if the wafers 10 and 10 are held on the two chuck tables 3 and 3, respectively, the chuck tables 3 and 3 are operated in the direction indicated by the arrow Y to move the wafers 10 and 10 to the alignment means 5. It is positioned in the imaging area of the imaging means 51 to be configured. When the chuck tables 3 and 3 are positioned in the imaging area of the imaging means 51, an alignment operation for detecting an exposure area in the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 by the imaging means 51 and a control means (not shown). Execute. That is, first, the image pickup means 51 is positioned immediately above the wafer 10 held on one chuck table 3, and a division line 101 formed in a predetermined direction of the wafer 10 is detected. The division line 101 is the mask means. Alignment is performed so as to be positioned parallel to the slit 611a formed in the upper wall 611 of 61. If the scheduled dividing line 101 formed in a predetermined direction and the slit 611a are not positioned in parallel, the pulse motor 44 of the index means 4 is operated to rotate one chuck table 3 and thus the wafer 10. By doing so, alignment is performed such that the planned dividing line 101 and the slit 611a are parallel to each other. In addition, alignment is similarly performed on the division line 101 formed in the direction orthogonal to the predetermined direction formed on the wafer 10. At this time, the surface 10a on which the planned dividing line 101 of the wafer 10 is formed is positioned on the lower side. However, as described above, the imaging unit 51 is an infrared illumination unit, an optical system that captures infrared rays, and an electrical system corresponding to infrared rays. Since it is composed of an image sensor (infrared CCD) or the like that outputs a signal, the wafer 10 can be imaged through the resist film 11 formed on the back surface b of the wafer 10. When the alignment operation for detecting the exposure region in the photosensitive resist film 11 formed on the back surface 10b of the wafer 10 held on one chuck table 3 is performed in this way, the imaging means 51 is moved to the arrow in FIG. The wafer is moved in the direction indicated by X and positioned immediately above the wafer 10 held on the other chuck table 3, and the above-described alignment operation is performed on the wafer 10 held on the other chuck table 3.

  As described above, when the division lines 101 formed on the wafers 10 and 10 held on the chuck tables 3 and 3 are detected and the exposure area is aligned, as shown in FIG. The chuck tables 3 and 3 holding the wafers 10 and 10 are moved in the direction indicated by the arrow Y1, that is, in the direction orthogonal to the slit 611a. The division line 101 is positioned immediately below the slit 611a formed in the upper wall 611 of the mask means 61. Next, the light emitting means 62 is energized, and slit light is exposed to the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 through the slit 611a (exposure process). The slit light exposes a region corresponding to the rightmost division planned line 101 in FIG. 3 in the division planned lines 101 formed on the wafers 10 and 10. By performing the exposure with the slit light for about 1 second, the photosensitive resist film 11 is exposed and removed along the division line 101.

  As described above, if the region corresponding to the rightmost division planned line 101 in FIG. 3 in the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 is removed, the index feeding means of the index means 4 and 4 will be described. By operating the pulse motors 452 and 452 constituting 45 and 45, the chuck tables 3 and 3 are moved in the direction indicated by the arrow Y1 by the interval of the above-mentioned division lines (indexing step). As a result, the second division planned line 101 from the rightmost end in FIG. 3 in the division division lines 101 formed on the wafers 10 and 10 held by the chuck tables 3 and 3 is formed on the upper wall 611 of the mask means 61. It is positioned directly below the slit 611a. And the said exposure process is implemented. In this way, by sequentially performing the indexing step and the exposure step, the region corresponding to the predetermined division line 101 in the predetermined direction in the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 can be removed. it can. Next, the pulse motors 44, 44 of the index means 4, 4 are operated to rotate the chuck tables 3, 3 by 90 degrees. As a result, the wafers 10, 10 held on the chuck tables 3, 3 are parallel to the slits 611 a formed on the upper wall 611 of the mask means 61 with the planned dividing lines 101 formed at right angles to the predetermined direction. Positioned. Then, by sequentially performing the indexing step and the exposure step described above, a region corresponding to the division lines formed at right angles to the predetermined direction in the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 is obtained. Exposed and removed.

  As described above, in the exposure apparatus in the illustrated embodiment, the index motors 4 and 4 of the index means 4 and 4 are operated to move the chuck tables 3 and 3 by the interval of the scheduled division lines formed on the wafer. Since the process and the exposure process of irradiating light to the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 through the slit 611a are sequentially performed, the mask means corresponding to the wafers having different intervals between the division lines There is no need to make 61 each time. In the illustrated embodiment, since the two chuck tables 3 and 3 are provided, the two wafers 10 and 10 can be exposed simultaneously. In the illustrated embodiment, an example in which the two chuck tables 3 and 3 are provided is shown, but three or more chuck tables may be provided.

  If the regions corresponding to all the division lines in the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 are exposed and removed as described above, the wafers 10 and 10 are the next process. For example, it is transferred to a plasma etching process.

Next, another embodiment of the mask means 61 will be described with reference to FIGS. FIG. 4 shows an exposure apparatus having another embodiment of the mask means 61. FIG. 5 shows a plurality of slit plates constituting the mask means 61 and a distance adjusting means for adjusting the distance between the plurality of slit plates. It is shown. 4 is substantially the same as the exposure apparatus shown in FIG. 1 except for the mask means 61, the same members are denoted by the same reference numerals, and the description thereof is omitted.
The mask means 61 shown in FIGS. 4 and 5 has a rectangular opening 611b formed in the upper wall 611, and three slit plates 71a, 71b, 71c each having a slit 711 in the opening 611b can adjust the interval. It is arranged. As shown in FIG. 5, the slit plates 71a, 71b, 71c provided with the slits 711 are provided with connecting portions 712, 712 formed by bending both ends thereof downward. The exposure apparatus in the illustrated embodiment includes an interval adjusting means 72 for adjusting the interval between the slit plates 711, 71 b, 71 c and thus the slits 711. The gap adjusting means 72 has links 721 and 722, one end of which is swingably connected to the connecting portions 712 and 712 of the slit plate 71a by a support shaft 73, and one end of each of the connecting portions 712 and 712 of the slit plate 71b. Links 723 and 724 that are swingably connected by the support shaft 73, links 725 and 726 that are swingably connected to the connection portions 712 and 712 of the slit plate 71c by the support shaft 73, and the link 723 A link mechanism comprising a link 728 having one end swingably connected to the other end of the link 726 and a link 729 having one end swingably connected to the other end of the link 726 by the support shaft 73. ing. The other end of the link 722 and the other end of the link 725 are connected to each other by a support shaft 73 so that the link 722 and the link 723 and the link 724 and the link 725 have their intermediate portions swinged by the support shaft 73. Connected as possible.

  The interval adjusting means 72 in the illustrated embodiment includes a pair of operating means 74 and 74 for operating the link mechanism. The actuating means 74, 74 are arranged in parallel to the outside of the pair of guide rails 41 and 41 of the index feeding means 45 on the base 2 (see FIG. 4). Each of the operating means 74 and 74 includes a drive source such as a male screw rod 741 and a pulse motor 742 for rotationally driving the male screw rod 741. One end of the male screw rod 741 is rotatably supported by a bearing block 743 fixed to the base 2 (see FIG. 4), and the other end is connected to the output shaft of the pulse motor 742. The male screw rod 741 is screwed with a through female screw hole 744 a formed in the female screw block 744. The other ends of the links 721 and 728 are swingably connected to the case of the pulse motor 742 in the operating means 74 configured as described above by the support shaft 73, and the links 726 and 729 are connected to the female screw block 744. The other ends are connected to each other by pivots 73 so as to be swingable. Therefore, when the male screw rod 741 is driven forward or reversely by the pulse motor 742, the male screw rod 741 is moved along the female screw block 744 in the index feed direction indicated by the arrow Y. As a result, the intervals between the slit plates 71a, 71b, 71c connected to the link mechanism are enlarged or reduced.

  Returning to FIG. 4, the description will be continued. A bellows 751 is disposed between the slit plates 71a and 71b, and a bellows 752 is disposed between the slit plates 71b and 71c. A bellows 753 is disposed between the slit plate 71a and one edge of the opening 611b formed in the upper wall 611 of the mask means 61, and between the slit plate 71c and the other edge of the opening 611b. A bellows 754 is provided. As described above, the bellows 751, 752, 753, and 754 disposed in the opening 611b portion formed on the upper wall 611 of the mask means 61 block the light from the light emitting means 62 and the slit plates 71a and 71b. , 71c.

The mask means 61 shown in FIGS. 4 and 5 is configured as described above, and exposure work using the mask means 61 will be described below.
First, the interval between the slits 711 and 711 formed in the slit plates 71a, 71b, and 71c of the mask means 61 is an integral multiple of the interval between the division lines 101 formed on the wafers 10 and 10 described above, and is the maximum. Adjustment is made so that the distance between the outer scheduled division line 101 and the outermost scheduled division line 101 on the opposite side is one third of the interval. This adjustment is performed by driving the pulse motor 742 of the interval adjusting means 72 forward or backward. Thus, if the distance between the slits 711 and 711 formed in the slit plates 71a, 71b and 71c of the mask means 61 is adjusted, the wafers held on the chuck tables 3 and 3 as described above. The division planned lines 101 formed at 10 and 10 are detected, and the alignment of the exposure area is executed. Then, as shown in FIG. 6, the chuck table 3 holding the wafers 10 and 10 is moved below the slit plates 71a, 71b and 71c, and is formed on the wafer 10 immediately below the slits 711 formed in the slit plate 71a. The rightmost division planned line 101 is positioned in the figure of the existing division planned line 101. As a result, the planned division line 101 corresponding to one third from the rightmost end in the drawing of all the planned division lines 101 formed in the wafers 10 and 10 is positioned immediately below the slit 711 formed in the slit plate 71b, The scheduled division line 101 corresponding to two-thirds from the rightmost end in the drawing of all the planned division lines 101 formed in the wafers 10 and 10 is positioned immediately below the slit 711 formed in the slit plate 71c.

  Next, the light emitting means 62 is energized to irradiate the photosensitive resist film 11 formed on the back surface 10b of the wafers 10 and 10 through the slit 711 formed in the slit plates 71a, 71b, 71c (exposure process). ). As a result, the photosensitive resist film 11 is exposed and removed along the three division lines 101 of the wafers 10 and 10 located immediately below the slits 711 formed in the slit plates 71a, 71b, and 71c.

  When the exposure process is performed as described above, the pulse motors 452 and 452 constituting the index feeding means 45 and 45 of the index means 4 and 4 are operated, and the chuck table 3 is spaced by the interval of the scheduled division line 101. 3 is moved in the direction indicated by the arrow Y1 (indexing step), and the above exposure step is performed, so that the wafers 10 and 10 can be exposed simultaneously along the three division lines 101. As described above, in the embodiment shown in FIGS. 4 to 6, the regions corresponding to the plurality of division lines 101 (three in the illustrated embodiment) in the photosensitive resist film 11 are simultaneously exposed and removed. This improves productivity. Further, since the interval between the slits 711 formed in the slit plates 71a, 71b, 71c can be adjusted by driving the pulse motor 742 of the interval adjusting means 72 in the normal direction or the reverse direction, the intervals between the division lines are different. Can handle wafers.

  In the above-described embodiment, an example in which the photosensitive resist film 11 is coated on the back surfaces of the wafers 10 and 10 has been described. However, the photosensitive resist film 11 may be coated on the surfaces of the wafers 10 and 10.

The perspective view which shows one Embodiment of the exposure apparatus comprised according to this invention. The perspective view which shows one Embodiment of the chuck table with which the exposure apparatus shown in FIG. 1 is equipped, and an index means. FIG. 2 is an explanatory view showing a state in which a wafer division schedule line held on a chuck table is positioned immediately below a slit of a mask means constituting the exposure apparatus shown in FIG. 1. The perspective view which shows other embodiment of the exposure apparatus comprised according to this invention. FIG. 5 is a perspective view of a slit plate and an interval adjusting unit constituting a mask unit provided in the exposure apparatus shown in FIG. 4. FIG. 5 is an explanatory view showing a state in which a division line of a wafer held on a chuck table is positioned immediately below a slit formed in a slit plate of a mask means constituting the exposure apparatus shown in FIG. 4. The perspective view of the wafer which is a workpiece. The perspective view which shows the state by which the photosensitive resist film was coat | covered on the back surface of the wafer shown in FIG.

Explanation of symbols

2: base 3: chuck table 4: index means 41, 41: guide rail 42: support base 44: pulse motor 45: index feed means 451: male screw rod 452: pulse motor 453: female screw block 5: alignment means 52 : Imaging means 6: Slit exposure means 61: Mask means 611a: Slit 62: Light emitting means 71a, 71b, 71c: Slit plate 711: Slit 712: Connecting part 72: Space adjusting means 74: Actuating means 741: Male screw rod 742: Pulse Motors 751, 752, 753, 754: bellows 10: wafer 101: division line 102: circuit 11: photosensitive resist film

Claims (4)

An exposure apparatus that exposes a resist film coated on a back surface or a surface of a wafer in which a functional element is formed in a region partitioned by a grid-like division line on the surface, along the division line,
A plurality of chuck tables holding wafers;
Alignment means for detecting division planned lines formed on the wafer respectively held by the plurality of chuck tables;
Slit exposure means for exposing slit light corresponding to the division lines to the resist film coated on the back surface or the front surface of the wafer respectively held by the plurality of chuck tables;
Index means for relatively moving the plurality of chuck tables and the slit exposure means and positioning the division lines formed on the wafers respectively held by the plurality of chuck tables at the exposure position of the slit light; Has
An exposure apparatus characterized by that.   2. The exposure apparatus according to claim 1, wherein the slit exposure means comprises mask means having at least one slit and light emitting means for exposing slit light through the slit of the mask means.   The exposure apparatus according to claim 2, wherein the mask unit includes a plurality of slits, and includes an interval adjusting unit that adjusts an interval between the plurality of slits.   The index means moves the plurality of chuck tables in a direction orthogonal to the slits, and positions a division line that extends in a predetermined direction formed on a wafer held by the plurality of chuck tables at an exposure position of the slit light. Parallel to the slit, the indexing feeding means and the dividing line in the direction perpendicular to the dividing line extending in a predetermined direction formed on the wafer held by the plurality of chuck tables by rotating the plurality of chuck tables. The exposure apparatus according to any one of claims 1 to 3, further comprising a rotating means positioned at the position.

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