Polishing device

Abstract

To provide a polishing device capable of suppressing a production cost.SOLUTION: A polishing device 1 comprises: a holding table 10 holding a workpiece 100; a polishing unit 30 which has a polishing tool 36 for polishing the workpiece 100 held on the holding table 10; a processing chamber 40 for storing therein, the holding table 10 and the polishing tool 36; and an exhaust unit 50 exhausting the inside of the processing chamber 40. The exhaust unit 50 has a control part 60 for adjusting an exhaust amount. The control part 60 adjusts the exhaust amount so as to exhaust the inside of the processing chamber 40 at a first exhaust amount in polishing by the polishing tool 36, and other than polishing by the polishing tool 36, adjusts the exhaust amount so as to exhaust the inside of the processing chamber 40 at a second exhaust amount lower than the first exhaust amount.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polishing apparatus. [Background technology]

[0002] Wafers, which have multiple devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) formed on their surface, have their back surfaces ground to a specified thickness, and then are separated into individual devices using a cutting machine for use in electrical equipment such as mobile phones and personal computers.

[0003] The grinding process for grinding the backside of a wafer uses a known grinding device, and a grinding wheel is attached to the spindle of the grinding device to perform rough grinding and finish grinding to a predetermined thickness (for example, Patent Document 1). During this process, saw marks and grinding distortion remain on the ground surface, so a polishing process is carried out after the grinding process to remove these marks and distortion. As one type of polishing process, the applicant has developed a polishing wheel that does not use a polishing liquid (also called a dry polishing wheel) and a polishing method that polishes in a dry state without supplying a polishing liquid (Patent Document 2).

[0004] During such polishing, dust such as polishing chips is generated, so the inside of the processing chamber including the polishing area of ​​the polishing device is constantly evacuated at a large volume by a dust collector (for example, Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-288881 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-093018 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-001118 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although dust such as polishing debris is generated during polishing, it is not generated outside of polishing, so there was a problem that if a large amount of exhaust air was discharged outside of polishing, production costs would increase.

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a polishing apparatus that can reduce production costs. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the polishing apparatus of the present invention comprises a holding table for holding a workpiece, a polishing unit equipped with a polishing tool for polishing the workpiece held on the holding table, a processing chamber that houses the holding table and the polishing tool, and an exhaust unit that evacuates the inside of the processing chamber, the exhaust unit having a control unit that adjusts the exhaust rate, and the control unit adjusts the exhaust rate so that the inside of the processing chamber is evacuated at a first exhaust rate during polishing with the polishing tool, and adjusts the exhaust rate so that the inside of the processing chamber is evacuated at a second exhaust rate lower than the first exhaust rate at times other than when polishing with the polishing tool is being performed. [Effects of the Invention]

[0009] The present invention can reduce production costs. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a polishing apparatus according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a schematic configuration of a polishing unit and a processing chamber of the polishing apparatus shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0012] In the embodiments described below, an XYZ Cartesian coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ Cartesian coordinate system. One direction within a horizontal plane is defined as the X-axis direction, the direction perpendicular to the X-axis direction within the horizontal plane is defined as the Y-axis direction, and the direction perpendicular to both the X-axis and Y-axis directions is defined as the Z-axis direction. The XY plane containing the X-axis and Y-axis is parallel to the horizontal plane. The Z-axis direction perpendicular to the XY plane is the vertical direction.

[0013] [Embodiment] A polishing apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of the configuration of the polishing apparatus 1 according to the embodiment. Fig. 2 is a cross-sectional view showing a schematic configuration of a polishing unit 30 and a processing chamber 40 of the polishing apparatus 1 shown in Fig. 1. As shown in Figs. 1 and 2, the polishing apparatus 1 according to the embodiment includes a holding table 10, a processing feed unit 20, the polishing unit 30, the processing chamber 40, and an exhaust unit 50.

[0014] The polishing apparatus 1 is an apparatus that performs dry polishing (dry polishing) on ​​a workpiece 100. The polishing apparatus 1 polishes, for example, the back surface 102 of the workpiece 100 that has been ground to remove grinding marks and grinding distortion. The workpiece 100 is, for example, a wafer such as a disk-shaped semiconductor wafer or optical device wafer, which has a substrate made of silicon (Si), sapphire (Al2O3), gallium arsenide (GaAs), silicon carbide (SiC), lithium tantalate (LiTaO3), or the like, and has a plurality of circuit elements such as ICs and LSIs formed on a surface 101.

[0015] The holding table 10 includes a disk-shaped suction portion formed of, for example, porous ceramic or the like, and has a holding surface 11 that holds the workpiece 100 on the horizontally flat upper surface of the suction portion. The holding surface 11 is connected to a vacuum suction source via, for example, a vacuum suction path, and suction-holds the front surface 101 of the placed workpiece 100.

[0016] The holding table 10 is provided on the upper surface of the equipment base 2 so as to be movable in the Y-axis direction and rotatable about an axis parallel to the Z-axis direction relative to the equipment base 2 extending in the Y-axis direction. The holding table 10 moves in the Y-axis direction between a loading / unloading area and a processing area by a moving means (not shown). The loading / unloading area is an area where the workpiece 100 is loaded and unloaded onto the holding table 10. The processing area is an area where the workpiece 100 is polished by a polishing unit 30 (described below). During polishing, the holding table 10 rotates about an axis parallel to the Z-axis direction by a rotating means (not shown). On both sides of the moving direction of the holding table 10, bellows covers 12 are provided in an expandable manner to cover the moving path and prevent processing debris and the like from falling into the equipment base 2.

[0017] The processing feed unit 20 is a unit that raises and lowers the polishing unit 30 in the Z-axis direction (processing feed direction). The processing feed unit 20 moves the holding table 10 and the polishing unit 30, which will be described later, relatively in the processing feed direction. The processing feed unit 20 of the embodiment moves the polishing unit 30 toward and away from the holding table 10, which is located in the processing area, in the Z-axis direction. The processing feed unit 20 is provided in front of the standing wall portion 3 that is erected on the rear side of the device base 2 in the Y-axis direction.

[0018] The processing feed unit 20 has a ball screw 21, a motor 22, a pair of guide rails 23, and a slide body 24 including a nut (not shown). The ball screw 21 extends in the Z-axis direction and is supported by the standing wall portion 3 so as to be rotatable about an axis parallel to the Z-axis direction. The motor 22 is connected to one end of the ball screw 21 and rotates the ball screw 21 about its axis. The pair of guide rails 23 extend parallel to the ball screw 21 and support a nut (not shown) so as to be movably in the Z-axis direction.

[0019] The slide body 24 includes a nut (not shown) that screws onto the ball screw 21, and slides in the Z-axis direction along a pair of guide rails 23. The slide body 24 also supports a housing 31 of the polishing unit 30. When the motor 22 rotates the ball screw 21, the processing feed unit 20 moves the slide body 24 up and down in the Z-axis direction along the guide rails 23, and moves the polishing unit 30 up and down together with the slide body 24 in the Z-axis direction.

[0020] The polishing unit 30 is a unit that performs dry polishing on the workpiece 100 held on the holding table 10 located in the processing area. The polishing unit 30 of the embodiment polishes, for example, the back surface 102 side of the workpiece 100 whose front surface 101 side is held on the holding surface 11 of the holding table 10. The polishing unit 30 is provided in front of the standing wall portion 3, and is supported by the slide body 24 of the processing feed unit 20.

[0021] The polishing unit 30 has a housing 31, a spindle 32, a spindle motor 33, a mount 34, a disk 35, and a polishing tool 36. The housing 31 is a spindle housing that surrounds the spindle 32. The housing 31 supports the spindle 32 so that it can rotate freely. The housing 31 is fixed to the slide body 24 of the processing feed unit 20.

[0022] The spindle 32 is supported by the housing 31 so as to be rotatable about an axis parallel to the Z-axis direction. A gap 321 provided between the housing 31 and the spindle 32 is connected to a high-pressure air supply source (not shown). The spindle 32 is rotatably supported without contact with the housing 31 by high-pressure air ejected into the gap 321.

[0023] The spindle motor 33 rotates the spindle 32. The spindle motor 33 includes a rotor 331 and a stator 332. The rotor 331 is fixed to the upper end side of the spindle 32 so as to be coaxial with the spindle 32. The stator 332 is fixed to the inner circumferential surface of the housing 31 so as to surround the rotor 331. When a predetermined voltage is applied to the stator 332, the rotor 331 and the spindle 32 rotate about their axes.

[0024] The mount 34 is coaxial with the spindle 32 and the rotor 331, and is formed in a disk shape having approximately the same diameter as the polishing tool 36 or a diameter larger than the polishing tool 36. The mount 34 is fixed to the lower end side of the spindle 32.

[0025] The disk 35 is coaxial with the mount 34 and has a disk shape that is substantially the same as the shape of the polishing tool 36. The disk 35 is detachably attached to the attachment surface, which is the lower surface side of the mount 34, by bolts or the like (not shown).

[0026] The polishing tool 36 is a disk-shaped dry polishing tool, such as a polishing pad made of urethane or nonwoven fabric. The polishing tool 36 is fixed to the underside of a disk 35, and is attached to the attachment surface, which is the underside of the mount 34, via the disk 35. The polishing tool 36 dry-polishes the workpiece 100 held on the holding table 10 with a polishing surface 361, which is the underside.

[0027] The processing chamber 40 accommodates the holding table 10 and at least the polishing tool 36 of the polishing unit 30, prevents contamination of the processing area, and prevents processing debris and the like from scattering to the outside. The processing chamber 40 is formed in a box shape (a rectangular parallelepiped shape in this embodiment). The processing chamber 40 is provided in front of the upright wall portion 3 and fixed to the apparatus base 2. The processing chamber 40 has an internal space surrounded by an upper plate 401 and multiple side plates 402. The processing chamber 40 also has a loading / unloading port (not shown), an opening / closing door 41, an opening / closing mechanism 42, an intake port 43, and an exhaust port 44.

[0028] An opening 403 is formed in the upper plate 401. The opening 403 is formed so that the polishing unit 30, which is raised and lowered in the Z-axis direction by the processing feed unit 20, can pass through. A bellows cover 37 that surrounds the spindle 32 is provided between the upper plate 401 and the lower end of the housing 31 around the periphery of the opening 403. The bellows cover 37 closes the opening 403 from the outside of the processing chamber 40, preventing processing debris and the like from scattering to the outside. The bellows cover 37 is deformable to follow the raising and lowering movement of the polishing unit 30 by the processing feed unit 20.

[0029] The side plate 402 is formed with a loading / unloading port (not shown), an intake port 43, and an exhaust port 44. The side plate 402 is also provided with a pair of guides 404 for supporting an opening / closing door 41 (described later) so that it can move freely in the Z-axis direction. The loading / unloading port is provided on the side plate 402 on the front side of the processing chamber 40 (on the loading / unloading area side relative to the processing area in the Y-axis direction), and is an opening through which the holding table 10 can pass as it moves between the loading / unloading area and the processing area.

[0030] The opening / closing door 41 opens and closes the loading / unloading opening. In this embodiment, the opening / closing door 41 has a plate shape extending in the XZ directions and is supported so as to be movable in the Z-axis direction. The opening / closing door 41 opens the loading / unloading opening by moving upward, and closes the loading / unloading opening by moving downward. The opening / closing mechanism 42 moves the opening / closing door 41 in the Z-axis direction. The opening / closing mechanism 42 includes, for example, an air cylinder and a piston. The opening / closing mechanism 42 can open and close the loading / unloading opening (not shown) by moving the opening / closing door 41 in the Z-axis direction along a pair of guides 404.

[0031] The intake port 43 is an opening for drawing air from the outside of the processing chamber 40 into the internal space. In this embodiment, the intake port 43 is provided in the side plate 402 near the opening / closing door 41. The exhaust port 44 is an opening for exhausting air from the inside of the processing chamber 40 to the exhaust unit 50. The exhaust port 44 is connected to the exhaust unit 50. In this embodiment, the exhaust port 44 is provided in the side plate 402 opposite to the side plate 402 on which the opening / closing door 41 is provided.

[0032] The exhaust unit 50 is a unit for exhausting air from the inside of the processing chamber 40 and sucking up machining chips generated inside the processing chamber 40 during polishing. The exhaust unit 50 is provided on the side of the apparatus base 2. The exhaust unit 50 has a housing 51, a dust collection tank 52, a recovery section 53, a plurality of filters 54, a plurality of reverse injection nozzles 55, a plurality of reverse injection valves 56, a reverse injection tank 57, a suction means 58, ducts 591 and 592, and a control section 60.

[0033] Housing 51 is formed in a rectangular parallelepiped shape and accommodates collection unit 53 and suction means 58 therein. Dust collection tank 52 is a cylindrical sealed container provided so as to protrude above housing 51. The interior of dust collection tank 52 is partitioned into separation chamber 521, air ejection chamber 522, and receiving unit 523.

[0034] In the separation chamber 521, the machining debris and the clean air are separated. The separation chamber 521 is connected to the exhaust port 44 of the processing chamber 40 via a duct 591. A plurality of filters 54 are arranged in the separation chamber 521. In the separation chamber 521, the plurality of filters 54 remove the machining debris from the air exhausted from the processing chamber 40, and the filtered clean air is ejected into the air ejection chamber 522. In addition, a nozzle (not shown) is provided in the separation chamber 521. The nozzle ejects cleaning water to wash away the machining debris adhering to the separation chamber 521.

[0035] The air ejection chamber 522 stores the clean air separated in the separation chamber 521. The air ejection chamber 522 is located above the separation chamber 521. The air ejection chamber 522 communicates with the suction means 58 via a duct 592. The air ejected into the air ejection chamber 522 is sucked in by the suction means 58 and exhausted outside the apparatus.

[0036] The receiving portion 523 is formed in a funnel shape that narrows downward at the lower end of the dust collection tank 52. In this embodiment, the receiving portion 523 is located inside the housing 51. A discharge port 524 is formed at the lower end of the receiving portion 523. The receiving portion 523 discharges, to the discharge port 524, waste liquid that contains processing debris washed out of the separation chamber 521 by the cleaning water.

[0037] The recovery unit 53 is in communication with the lower side of the discharge port 524. The recovery unit 53 recovers the waste liquid containing the processing debris that has dropped from the discharge port 524. A duct (not shown) is connected to the recovery unit 53 for discharging the waste liquid containing the processing debris outside the apparatus.

[0038] The filters 54 are disposed in the separation chamber 521 and filter the air exhausted from the processing chamber 40 to separate it into processing debris and clean air. In the embodiment, three filters 54 are provided, but one, two, or four or more filters may be provided. The filters 54 are formed in a cylindrical shape extending in the Z-axis direction. A central hole 541 at the center of the cylindrical shape of the filter 54 is a vent hole through which air passes. The central hole 541 is closed at its lower end and communicates with the air ejection chamber 522 at its upper end. When air exhausted from the processing chamber 40 through the duct 591 passes from the outer periphery of the filter 54 toward the central hole 541, processing debris contained in the air is removed, and clean air is ejected from the central hole 541 into the air ejection chamber 522.

[0039] The multiple reverse injection nozzles 55 are disposed at the upper end of the air injection chamber 522 of the dust collection tank 52, and inject high-pressure air toward the central hole 541 of the filter 54. One reverse injection nozzle 55 is provided for each filter 54. The high-pressure air injected from the reverse injection nozzle 55 passes from the central hole 541 of the filter 54 toward the outer periphery, i.e., in the opposite direction to the direction in which the air exhausted from the machining chamber 40 is filtered. This causes machining debris accumulated on the filter 54 to be blown out toward the outer periphery and removed from the filter 54. It is preferable to clean the filter 54 periodically, for example, while the exhaust unit 50 is operating.

[0040] A plurality of reverse jet valves 56 are disposed above the dust collection tank 52 and connected to the reverse jet nozzles 55 so as to be able to open and close the reverse jet nozzles 55. One reverse jet valve 56 is provided for each reverse jet nozzle 55. A reverse jet tank 57 is attached to the side of the dust collection tank 52 and is filled with high-pressure air. The reverse jet tank 57 is connected to the air ejection chamber 522 via piping. By opening the reverse jet valve 56, the high-pressure air filled in the reverse jet tank 57 is ejected from the reverse jet nozzle 55 toward the center hole 541 of the filter 54.

[0041] Suction means 58 is provided inside housing 51 and communicates with air ejection chamber 522 of dust collection tank 52 via duct 592. Suction means 58 sucks in clean air that has been ejected into air ejection chamber 522 from central hole 541 of filter 54 and exhausts the air to the outside of the device. Suction means 58 includes, for example, a fan whose rotation speed is adjustable.

[0042] The control unit 60 controls each component of the exhaust unit 50. For example, the control unit 60 controls the reverse injection valve 56 to clean the filter 54. For example, the control unit 60 controls the suction means 58 to exhaust air from the machining chamber 40 via a duct 592. The control unit 60 can adjust the amount of air exhausted from the machining chamber 40 by the exhaust unit 50. The adjustment of the amount of air exhausted can be achieved, for example, by changing the rotation speed of the fan of the suction means 58. For example, the control unit 60 adjusts the amount of air exhausted so that the interior of the machining chamber 40 is exhausted at a first amount of air exhaust during polishing using the polishing tool 36. For example, the control unit 60 adjusts the amount of air exhausted so that the interior of the machining chamber 40 is exhausted at a second amount of air exhaust during times other than polishing.

[0043] The first exhaust volume during polishing is set to 4 m so that processing debris is sufficiently discharged from the processing chamber 40. 3 / min or more 6m 3 / min or less, average 5m 3 / min, for example, 5m in this embodiment. 3The second exhaust volume is set to 1 m / S. Note that the term "during polishing" includes the time when the workpiece 100 held on the holding table 10 is polished by the polishing tool 36, and the time when the polishing tool 36 is dressed. The second exhaust volume during times other than polishing is set to 1 m / S so that the second exhaust volume is at least lower than the first exhaust volume and air can flow in from the intake port 43. 3 / min or more 3m 3 / min or less, average 2m 3 / min, for example, in the embodiment, 3 / S. Note that "non-polishing" refers to a situation where no processing debris is generated, such as when the apparatus is warming up, when the workpiece 100 is drying, or when the workpiece 100 is being cleaned. In other words, "non-polishing" refers to a situation where the holding table 10 is not positioned in the processing area, or a situation where the workpiece 100 held by the holding table 10 is not in contact with the polishing tool 36 even if it is positioned in the processing area.

[0044] The control unit 60 may be realized, for example, as part of a control device that controls each component of the polishing apparatus 1. The control device is a computer including an arithmetic processing unit as a calculation means, a storage device as a storage means, and an input / output interface device as a communication means. The arithmetic processing unit includes, for example, a microprocessor such as a CPU (Central Processing Unit). The storage device has a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The arithmetic processing unit performs various calculations based on predetermined programs stored in the storage device. In accordance with the calculation results, the arithmetic processing unit outputs various control signals to each of the above-mentioned components via the input / output interface device, thereby controlling the polishing apparatus 1.

[0045] As described above, the polishing apparatus 1 according to the embodiment evacuates the processing chamber 40 at a second exhaust rate that is lower than the first exhaust rate during grinding processing, except during grinding processing, thereby suppressing the increase in the amount of electricity required to always exhaust at a large exhaust rate and the resulting increase in production costs.

[0046] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0047] 1 Polishing equipment 10 Holding table 20 Processing feed unit 30 Polishing Unit 36 Polishing tools (polishing pads) 40 Processing room 43 Air intake 44 exhaust port 50 Exhaust unit 60 Control Unit 100 Workpiece

Claims

[Claim 1] A polishing apparatus comprising: a holding table for holding the workpiece; a polishing unit including a polishing tool for polishing the workpiece held on the holding table; a processing chamber that accommodates the holding table and the polishing tool therein; an exhaust unit that exhausts the inside of the processing chamber; Equipped with The exhaust unit comprises: A control unit for adjusting the exhaust amount is provided. The control unit adjusting the exhaust rate so that the inside of the processing chamber is evacuated at a first exhaust rate during polishing processing with the polishing tool, and adjusting the exhaust rate so that the inside of the processing chamber is evacuated at a second exhaust rate lower than the first exhaust rate when polishing processing with the polishing tool is not being performed; Polishing equipment.

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