JP2019098503A - Dry type polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent processing chips from adhering to a polishing pad or a wafer. A dry polishing apparatus includes a polishing means 3 for polishing a wafer W with a dry polishing pad 30, and a processing chamber 4 for covering a holding table 2 and a polishing pad 30, and the polishing means 3 has a disk shape. The mount 32 is formed with a diameter larger than the diameter of the polishing pad 30 and protrudes outward from the outer peripheral edge of the polishing pad 30. The processing chamber 4 is provided with fins 37 for generating an updraft Ud from the mounting surface 32a side of the mount 32 toward the opposite surface 32b side, and the processing chamber 4 is provided with an exhaust portion 43 connected to the dust collector 6 on the upper plate 400 and rises. Since the processing waste Ad is configured to be guided to the exhaust port 46 by the air flow Ud, the processing waste Ad can be efficiently sucked by the dust collector 6, and the processing waste Ad does not adhere to the wafer W and the polishing pad 30, causing polishing defects. There is no. [Selection diagram] FIG. 4

Description

  The present invention relates to a polishing apparatus that performs dry polishing on a wafer.

  When grinding and thinning the back surface of the wafer with devices formed on the front surface with a grinding stone, grinding marks are formed on the surface to be ground of the wafer and the bending strength of the chips is reduced, so grinding marks on the surface to be ground It is processed and removed, and divided into devices to form chips. By removing the grinding marks, the chipping strength is increased, and the chip reliability is improved.

  The polishing process includes CMP polishing process using a polishing solution and dry polishing process using no polishing solution. In dry-type polishing, a disk-shaped polishing pad formed by including abrasive grains is brought into contact with a wafer for polishing (see, for example, Patent Document 1 below). The dry-type polishing apparatus includes a processing chamber that holds a holding table for holding a wafer and a polishing pad, and in the processing chamber during polishing processing, processing dust due to powder consumed by the polishing pad and powder from which the wafer is polished are scattered ing. Therefore, in order to discharge the processing waste out of the processing room, the processing chamber is sucked to a negative pressure using a dust collector provided outside the processing room, and the processing waste is discharged out of the apparatus.

Unexamined-Japanese-Patent No. 2006-315090

  However, in the dry type polishing apparatus as described above, the dust can not sufficiently suck the processing waste from the processing chamber, and the processing waste may adhere to the polishing pad or the wafer to cause polishing failure.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to prevent processing debris from adhering to a polishing pad or a wafer.

  The present invention comprises a holding table for holding a wafer, a polishing means for rotatably mounting a disk-shaped dry polishing pad and polishing the wafer held by the holding table, and covering the holding table and the polishing pad. A dry polishing apparatus comprising a box-like processing chamber for polishing a wafer in the processing chamber, the polishing means having a mounting surface and aligning the center of the polishing pad with the center of the mounting surface A disk-like mount for mounting the polishing pad, a spindle having the center of the mount as an axis and mounting the tip on the opposite surface of the mounting surface, a spindle unit for rotatably supporting the spindle, the spindle And a rotating means for rotating the mount, the mount being formed with a diameter larger than the diameter of the polishing pad and protruding from the outer peripheral edge of the polishing pad to the outside, and an annular portion on the protruding portion And a fin which is disposed and generates an upward air flow from the mounting surface side of the mount to the opposite surface side by rotation of the spindle, and the processing means is passed through the upper plate of the processing chamber by the polishing means. And an exhaust part having an exhaust port connected to a dust collector that sucks the processing chamber into the upper plate, the polishing being generated by the rising air flow generated when the mount is rotated Processing waste can be led to the exhaust port.

  The exhaust portion includes a guide portion formed in an annular shape surrounding the opening and having a groove-shaped cross section with an open lower surface, and the exhaust port disposed on a ceiling plate of the guide portion, the ceiling plate It is possible to guide processing waste to the exhaust port by inclining so that the place where the exhaust port is disposed is the highest.

  The dry polishing apparatus according to the present invention comprises a holding table for holding a wafer, a polishing means for rotatably mounting a disk-like dry polishing pad and polishing the wafer held by the holding table, the holding table, and And a box-like processing chamber for covering the polishing pad, the polishing means having a mounting surface, and a disc for mounting the polishing pad with the center of the polishing pad and the center of the mounting surface in alignment. The mount is formed to have a diameter larger than the diameter of the polishing pad, and the protrusion protruding outward from the outer peripheral edge of the polishing pad, and annularly disposed on the protrusion, and rotated by the spindle. And a fin for generating an upward air flow from the mounting surface side of the mount toward the opposite surface side, wherein the processing chamber is an opening through which the polishing means passes through the upper plate of the processing chamber, and the lift The processing room in the upper plate And an exhaust unit having an exhaust port connected to the dust collector for sucking the air, and the processing is performed such that processing debris generated in the polishing process is guided to the exhaust port by the upward airflow generated when the mount is rotated. Processing dust flying in the room can be efficiently sucked from the exhaust port by the dust collector. As a result, no processing debris adheres to the polishing surface of the wafer or polishing pad, so that no polishing failure occurs.

  The exhaust portion includes a guide portion formed in an annular shape surrounding the opening and having a groove-shaped cross section with an open lower surface, and the exhaust port disposed on a ceiling plate of the guide portion, the ceiling plate Since the air outlet is inclined so that the place where the exhaust port is disposed is the highest, the updraft generated when the mount is rotated is guided along the guide portion, and the ceiling plate is inclined. Since it flows along the side of the exhaust port, the processing dust flying in the processing chamber is easily guided to the exhaust port, and the dust can be sufficiently sucked by the dust collector.

It is a perspective view showing the composition of a dry polisher. It is sectional drawing which shows the structure of a grinding | polishing means and a processing chamber. It is a perspective view which shows the structure of a part of grinding | polishing means. It is sectional drawing which shows the state which grinds and processes a wafer in a process chamber.

  The dry polishing apparatus 1 shown in FIG. 1 is an example of a polishing apparatus which performs dry polishing on a workpiece such as a wafer. The dry polishing apparatus 1 has an apparatus base 100 extending in the Y-axis direction, and a holding table 2 for holding the wafer W shown in FIG. 2 is provided on the apparatus base 100. The upper surface of the holding table 2 is a holding surface 2 a that suctions and holds the wafer W, and a suction source (not shown) is connected to the holding surface 2 a. Although not shown, a motor for rotating the holding table 2 and moving means for moving the holding table 2 in the horizontal direction (Y-axis direction) are connected to the lower side of the holding table 2.

  A column 101 is provided upright on the rear side of the device base 100 in the Y-axis direction. In front of the column 101, a polishing means 3 for dry-polishing the wafer W held by the holding table 2, a box-like processing chamber 4 for covering the holding table 2 and a polishing pad 30 described later, and a polishing means 3 And elevating means 5 for moving up and down in the vertical direction (Z-axis direction). On the side of the device base 100, a dust collector 6 is provided which sucks processing waste generated inside the processing chamber 4 during polishing.

  The lifting means 5 comprises a ball screw 50 extending in the Z-axis direction, a motor 51 connected to one end of the ball screw 50, a pair of guide rails 52 extending parallel to the ball screw 50, And an elevator plate 53 connected to the A pair of guide rails 52 are in sliding contact with the other surface of the lift plate 53, and a ball screw 50 is screwed into a nut formed at the central portion of the lift plate 53. When the motor 51 rotates the ball screw 50, the elevating plate 53 is moved up and down in the Z-axis direction by being guided by the guide rails 52, so that the polishing means 3 can be moved up and down in the Z-axis direction together with the elevating plate 53.

  As shown in FIG. 2, the polishing means 3 has a disk-like dry polishing pad 30, a mounting surface 32a, and the center of the polishing pad 30 aligned with the center of the mounting surface 32a to mount the polishing pad 30. Disk-shaped mount 32, a spindle 33 having its tip mounted on the opposite surface 32b of the mounting surface 32a with the center of the mount 32 as its axis, a spindle unit 34 for rotatably supporting the spindle 33, and the spindle 33 And rotating means 35 for rotating.

  The spindle unit 34 is a spindle housing that rotatably encloses the spindle 33. A high pressure air supply source is connected to the spindle unit 34, and for example, high pressure air is jetted into a gap 340 provided between the spindle unit 34 and the spindle 33. Thus, the spindle 33 is rotatably supported by the high pressure air jetted into the gap 340 without contacting the spindle unit 34.

  The rotating means 35 is composed of a rotor (not shown) fixed to the outer peripheral surface on the upper end side of the spindle 33 and a stator 350 fixed to the inner peripheral surface of the spindle unit 34 so as to surround the rotor. When a predetermined voltage is applied to the stator 350, the rotor rotates, and the spindle 33 rotates about its axis.

  The polishing pad 30 is made of, for example, urethane or non-woven fabric. The lower surface of the polishing pad 30 is a polishing surface 30 a for dry-polishing the wafer W. The polishing pad 30 is fixed to a disc 31 having substantially the same diameter as the polishing pad 30, and is attached to the mounting surface 32 a of the mount 32 via the disc 31. The disc 31 is detachably attached to the mount 32 by a bolt or the like (not shown).

  The mount 32 is formed with a diameter larger than the diameter of the polishing pad 30 and protrudes from the outer peripheral edge of the polishing pad 30 and the opposite surface of the mounting surface 32 a from the mounting surface 32 a side of the mount 32 by rotation of the spindle 33. It has a fin 37 for generating an ascending air flow toward the side 32b, and also functions as a fan utilizing centrifugal force generated by the rotation of the spindle 33.

  The polishing means 3 shown in FIG. 3 schematically shows the configuration of the protruding portion 36 and the fins 37 provided on the mount 32. As shown in FIG. The protruding portion 36 is an annular member disposed covering the periphery of the mount 32. In the protruding portion 36, an air gap 360 is formed between the peripheral edge portions 36a and 36b on the outer peripheral side. A plurality of fins 37 are disposed in an annular shape as a whole in the air gap 360. The diameter of the protruding portion 36 is not particularly limited as long as the diameter is larger than the diameter of the polishing pad 30.

  The adjacent fins 37 are parallel to each other, and the lower end of the fins 37 is directed downward to the rotational direction (for example, counterclockwise direction) of the spindle 33 and the upper end of the fins 37 is directed upward in the opposite direction to the rotational direction of the spindle 33. It is inclined to become. By rotating the plurality of fins 37 as the mount 32 rotates, air is pumped around the protruding portion 36 to generate a pressure difference between the center side and the outer side of the mount 32, and the mounting surface 32a of the mount 32 is obtained. It is possible to generate an upward air flow from the side toward the opposite surface 32b.

  The processing chamber 4 shown in FIG. 1 has an internal space surrounded by the upper plate 400 and a plurality of side plates 401. An entrance (not shown) through which the holding table 2 can pass, an opening / closing door 40 for opening / closing the entrance, and an opening / closing door 40 on the side plate 401 on the front side (front side in the Y-axis direction) of the processing chamber 4. And an opening / closing mechanism 41 for moving the in the vertical direction. The opening and closing mechanism 41 includes, for example, an air cylinder and a piston, and can open and close the entrance by moving the opening and closing door 40 in the vertical direction along a pair of guides 402 disposed on the side plate 401. it can. In the vicinity of the open / close door 40, an intake port 47 is disposed.

  As shown in FIG. 2, the processing chamber 4 has an opening 42 through which the polishing means 3 passes through the upper plate 400 and can be raised and lowered, and an exhaust port 46 connected to the dust collector 6 sucking the inside of the processing chamber 4 into the upper plate 400. An exhaust unit 43 is provided. A bellows cover 48 surrounding the spindle 33 is disposed between the lower end of the spindle unit 34 and the upper plate 400. The bellows cover 48 closes the opening 42 to prevent the swarf generated during the polishing process from scattering to the outside of the processing chamber 4. Although the material of the bellows cover 48 is not particularly limited, the bellows cover 48 can be deformed following the elevating movement of the polishing means 3 by the elevating means 5.

  The exhaust unit 43 is provided with a guide portion 44 which is formed in an annular shape surrounding the opening 42 and has a groove-like cross section with an open lower surface and an exhaust port 46 disposed in the ceiling plate 45 of the guide portion 44 . The guide portion 44 shown in the present embodiment is formed to have a substantially U-shaped cross section, and a concave groove 440 in which a space opened on the lower surface of the guide portion 44 (the lower surface of the ceiling plate 45) is a passage of air flow It has become. The guide part 44 is not limited to the structure shown to this embodiment, For example, it may be formed in the cross-sectional substantially U-shape.

  Further, the ceiling plate 45 is inclined such that the location where the exhaust port 46 is disposed is the highest. The ceiling plate 45 shown in the present embodiment is gently inclined so as to be higher toward the exhaust port 46 side. According to the exhaust unit 43 configured as described above, the updraft generated when the mount 32 is rotated is guided along the groove 440 and is directed to the exhaust port 46 side along the inclination of the ceiling plate 45. As it flows, the machining chips flying in the processing chamber 4 are easily guided to the exhaust port 46, and the dust can be sufficiently sucked by the dust collector 6. The processing chamber 4 is set to such a size that not only the holding table 2 and the polishing pad 30 attached to the mount 32 but also the whole of the protruding portion 36 can be inserted. Therefore, when the diameter of the protruding portion 36 is changed, the size of the processing chamber 4 may be appropriately changed according to the change. The ceiling plate 45 is not limited to the illustrated configuration, and the inclination angle may be changed as appropriate according to the size of the processing chamber 4.

  The dust collector 6 includes a rectangular parallelepiped housing 60 shown in FIG. 1, a cylindrical dust collection tank 61 disposed on the housing 60, and a plurality of reverse injection nozzles 64 disposed on the upper end of the dust collection tank 61. And a plurality of reverse injection valves 65 connected to the reverse injection nozzle 64, a reverse injection tank 66 attached to the side of the dust collection tank 61 and filled with high pressure air, and suction provided inside the housing 60. And a valve control unit 68 disposed on the side of the housing 60 to control the opening and closing of the reverse injection valve 65.

  The inside of the dust collection tank 61 is divided into a separation chamber 61 a for separating processing waste and air, and an air ejection chamber 61 b. The separation chamber 61a is connected to the exhaust port 46 of the processing chamber 4 by a duct 69a. In the separation chamber 61a, a plurality of (for example, three) filters 63 are disposed in order to filter the air exhausted from the processing chamber 4. At the center of the filter 63, a central hole 630 which is a passage of air is formed. The lower end of the central hole 630 is closed, and the upper end of the central hole 630 communicates with the air ejection chamber 61 b. When the air exhausted from the processing chamber 4 passes through the filter 63, the processing debris contained in the air is removed, and clean air is ejected from the central hole 630 to the air ejection chamber 61b. The air ejection chamber 61b is connected to the suction means 67 by a duct 69b. Then, the air jetted into the air jet chamber 61b is sucked by the suction unit 67 and exhausted to the outside of the apparatus.

  In the air ejection chamber 61b, three reverse injection nozzles 64 and three reverse injection valves 65 are disposed in order to remove the processing wastes accumulated in the three filters 63. The reverse injection tank 66 is connected to the air ejection chamber 61 b via a pipe. When the reverse injection valve 65 is opened, the high pressure air of the reverse injection tank 66 is injected from the reverse injection nozzle 64 toward the center hole 630 of the filter 63. As a result, high pressure air flows in the opposite direction (direction from the center hole 630 side to the outer peripheral side) when filtering the air exhausted from the processing chamber 4, and thus the machining waste accumulated in the filter 63 is blown away to the outside. , Filter 63 can be cleaned. The timing for cleaning the filter 63 is not particularly limited, but is preferably performed periodically during operation of the dust collector 6.

  The lower end of the dust collection tank 61 is a funnel-shaped receiving portion 610 whose diameter is reduced downward, and a discharge port 611 is formed at the center of the receiving portion 610. Although not shown, the separation chamber 61a is provided with a nozzle for injecting washing water, and the processing debris attached to the separation chamber 61a can be washed away with the washing water. Below the discharge port 611, a recovery unit 62 is disposed which recovers the waste liquid containing the processing scraps dropped from the discharge port 611. A duct (not shown) is connected to the recovery unit 62, and the waste liquid containing processing waste can be discharged to the outside of the apparatus. The dust collector 6 configured as described above is always operated during the polishing process of the wafer W.

  Next, an operation example of the dry polishing apparatus 1 will be described. As shown in FIG. 2, when the wafer W is placed on the holding surface 2a of the holding table 2, the wafer W is suctioned and held by the holding surface 2a by the suction force of the suction source. Subsequently, the open / close door 40 shown in FIG. 1 is opened, and the holding table 2 is made to enter the inside of the processing chamber 4 from the entrance and the holding table 2 is moved to the lower side of the polishing means 3.

  As shown in FIG. 4, when the polishing process is started by the polishing means 3, the holding table 2 is rotated, for example, in the arrow A direction, and the spindle 33 is used to rotate the polishing pad 30, for example, in the arrow A direction. Thus, the spindle unit 34 is lowered in the Z axis direction approaching the holding table 2. In the processing chamber 4, for example, while the holding table 2 is horizontally moved in the Y axis direction, the polishing surface 30 a of the polishing pad 30 and the wafer W are relatively slid and polished. At this time, the bellows cover 48 is contracted in the vertical direction following the downward movement of the spindle unit 34.

  In the processing chamber 4, processing scrap Ad generated when the polishing pad 30 polishes the wafer W is scattered. During the polishing process of the wafer W, the dust collector 6 is always operated to make the inside of the processing chamber 4 a negative pressure and suck the processing waste Ad from the exhaust port 46 through the duct 69 a.

  Furthermore, during the polishing process of the wafer W, the fins 37 are also rotated along with the mount 32 by the rotating spindle 33, so an upward air flow Ud is generated from the mounting surface 32a side of the mount 32 toward the opposite surface 32b Let The rising air flow Ud can guide the processing scrap Ad scattering around the polishing pad 30 to the upper side (exhaust portion 43 side) of the processing chamber 4. Then, the processing scrap Ad pushed upward by the updraft Ud flows along the ceiling plate 45 of the guide portion 44 to the exhaust port 46, so that the processing scrap Ad in the processing chamber 4 is sufficiently made by the dust collector 6. It can be aspirated.

  After completion of the polishing, the polishing means 3 is lifted by the lifting means 5 and retracted from the wafer W. Then, after the holding table 2 is moved outward from the processing chamber 4, the wafer W is transferred from the holding table 2 to the apparatus of the next process (for example, the cleaning apparatus) by a transfer unit (not shown).

  As described above, the dry polishing apparatus 1 according to the present invention rotatably mounts the holding table 2 for holding the wafer W and the disk-shaped dry polishing pad 30 and polishes the wafer W held by the holding table 2. A polishing means 3 and a box-like processing chamber 4 covering the holding table 2 and the polishing pad 30 are provided. The polishing means 3 has a mounting surface 32 a and the center of the polishing pad 30 coincides with the center of the mounting surface 32 a. A disk-like mount 32 for mounting the polishing pad 30, and the mount 32 is formed with a diameter larger than the diameter of the polishing pad 30, and has a protruding portion 36 protruding outside the outer peripheral edge of the polishing pad 30, And a fin 37 disposed annularly in the protruding portion 36 and generating an upward air flow Ud from the mounting surface 32a side to the opposite surface 32b side of the mount 32 by rotation of the spindle 33, The work room 4 has an opening 42 through which the polishing means 3 passes through the upper plate 400 of the processing chamber 4 and can be raised and lowered, and an exhaust unit 43 having an exhaust port 46 connected to the upper plate 400 to the dust collector 6 to suck the inside of the processing chamber 4 , And the processing scrap Ad generated in the polishing process is guided to the exhaust port 46 by the upward air flow Ud generated when the mount 32 is rotated, so the processing scrap Ad fluctuating in the processing chamber 4 is discharged through the exhaust port The dust can be efficiently sucked by the dust collector 6 through 46. As a result, no processing scrap Ad adheres to the wafer W or the polishing surface 30 a of the polishing pad 30, so that polishing defects are not generated.

1: Dry polishing apparatus 2: Holding table 3: Polishing means 30: Polishing pad 31: Disc 32: Mount 32a: Mounting surface 32b: Opposite surface 33: Spindle 34: Spindle unit 35: Rotational unit 36: Projection unit 37: Fin 4: Processing room 40: Opening and closing door 41: Opening and closing mechanism 42: Opening 43: Exhaust part 44: Guide part 45: Ceiling plate 46: Exhaust port 47: Intake port 48: Bellows cover 5: Lifting means 50: Ball screw 51: Motor 52 Guide rail 53: Lifting plate 6: Dust collector 60: Housing 61: Dust collection tank 61a: Separation chamber 61b: Air ejection chamber 62: Recovery unit 63: Filter 64: Reverse injection nozzle 65: Reverse injection valve 66: Reverse injection air tank 67 : Suction unit 68: Valve control unit 69a, 69b: Duct

Claims (2)

A holding table for holding a wafer, a polishing means for rotatably mounting a disk-like dry polishing pad and polishing the wafer held by the holding table, and a box-like processing for covering the holding table and the polishing pad A dry polishing apparatus for polishing a wafer in the processing chamber, comprising: a chamber;
The polishing means has a mounting surface, and a disk-like mount for mounting the polishing pad with the center of the polishing pad and the center of the mounting surface in alignment.
A spindle whose center is the center of the mount and whose tip is mounted on the opposite side of the mounting surface;
A spindle unit rotatably supporting the spindle;
And rotating means for rotating the spindle,
The mount is formed with a diameter larger than the diameter of the polishing pad, and a protrusion which protrudes outside the outer peripheral edge of the polishing pad;
And a fin disposed annularly in the protruding portion and generating an upward air flow from the mounting surface side of the mount toward the opposite surface side by rotation of the spindle.
The processing chamber has an opening through which the polishing means passes through the upper plate of the processing chamber and can be raised and lowered;
And an exhaust unit having an exhaust port connected to a dust collector for sucking the processing chamber into the upper plate,
A dry-type polishing apparatus for introducing, to the exhaust port, cutting debris generated by polishing due to the upward air flow generated when the mount is rotated. The exhaust portion includes a guide portion formed in an annular shape surrounding the opening and having an open lower surface and having a grooved cross section, and the exhaust port disposed on a ceiling plate of the guide portion.
The dry polishing apparatus according to claim 1, wherein the ceiling plate is inclined so as to be the highest at a position where the exhaust port is disposed, and guides the processing waste to the exhaust port.

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