JP2011083864A - Machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining device having an air bearing spindle capable of stably driving with low air consumption. <P>SOLUTION: The machining device includes a spindle unit 6 having: a spindle 60 which is formed such that a flange 601 radially projects from an outer circumference of a main shaft 600; a housing 61 which houses the spindle 60; a radial air bearing 63 which forms an air layer with the main shaft 600 and supports the spindle 60; a thrust air bearing 64 which forms an air layer with the flange 601 and supports the spindle 60; an air flow path 62 which has an air regulating valve 8 for delivering air used by the radial air bearing 63 and the thrust air bearing 64, in which a machining tool 31 is mounted to an end of the spindle 60. The machining device further includes an air regulating valve control means 9 for regulating the air regulating valve 8 during machining and during non-machining. During non-machining, an amount of air enough for preventing the spindle 60 and an inner wall of the housing 61 from contacting each other is delivered between the spindle and the inner wall of the housing. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a processing apparatus having a gas bearing.

  When grinding the surface of a plate-like workpiece such as a semiconductor wafer, glass, ceramics, etc. to a desired thickness, a grinding apparatus is used that grinds by pressing a rotating grindstone against the workpiece. . For example, as disclosed in Patent Document 1, such a grinding apparatus is provided with a chuck table for holding a workpiece, a turntable for positioning the chuck table in an attachment / detachment region and a grinding region by rotation, and a grinding region. And a grinding means having a grinding wheel for grinding the workpiece held on the chuck table, and a grinding wheel is fixed to the lower part of the grinding wheel. As the grinding means, a structure is used in which the spindle is rotatably supported by a gas such as air, and a grinding wheel is fixed to the tip of the spindle.

  For example, as shown in Patent Document 2, a cutting apparatus that cuts a workpiece and divides the workpiece into individual chips includes a chuck table that holds the workpiece, and a workpiece that is held by the chuck table. Cutting means having a cutting blade for cutting an object. As the cutting means, one having a configuration in which the spindle is rotatably supported by a gas such as air and a cutting blade is fixed to the tip of the spindle is used.

  As described above, in a processing apparatus configured to rotate a processing tool such as a grinding apparatus and a cutting apparatus, a gas bearing spindle is used for stable driving of the spindle. Conventionally, the spindle is driven under the same conditions as during machining even when machining is not being performed.

JP-A-10-86048 JP 2000-21822 A

  However, in recent years, there is a high demand for reducing the amount of gas such as air used in the processing apparatus, and there is a demand for a processing apparatus having a gas bearing spindle that can be stably driven with a smaller amount of gas.

  The present invention has been made in view of these facts, and a main technical problem thereof is to provide a machining apparatus having a gas bearing spindle that can be stably driven with less gas consumption.

  The present invention relates to a spindle having a cylindrical main shaft portion and a flange portion radially projecting from the outer periphery of the main shaft portion, the shaft centering on the axis of the main shaft portion, a housing for housing the spindle, and the main shaft portion of the spindle And a radial air bearing that supports the spindle in a direction perpendicular to the direction of the rotation axis, and is formed between the flange of the spindle and the inner wall of the housing. A spindle having a thrust air bearing formed by a gas layer and supporting the spindle in the direction of the rotation axis, and a gas flow path for feeding gas between the spindle and the inner wall of the housing to form a radial air bearing and a thrust air bearing A unit, a machining tool attached to the tip of the spindle, and a workpiece to be machined with the machining tool A processing device having a holding table to be held, and a moving means for relatively moving the spindle unit and the holding table, having a gas adjusting valve provided in the gas flow path for adjusting the flow rate of the gas, and a processing tool When the work piece is not machined, the gas regulating valve is controlled so as to feed an amount of gas between the spindle and the inner wall of the housing so that the main shaft portion and the flange portion of the spindle do not contact the inner wall of the housing. Gas processing valve control means is provided for controlling the gas control valve so as to feed an amount of gas capable of appropriate processing between the spindle and the inner wall of the housing when processing the workpiece.

  A machining apparatus according to the present invention includes a gas regulating valve that adjusts a flow rate of a gas fed between a spindle and an inner wall of a housing, and a gas regulating valve that controls the gas regulating valve depending on whether or not machining is performed by a machining tool. Control means, the gas regulating valve control means, by performing control to reduce the amount of gas used during the processing is less than the amount of gas required when processing, Gas can be saved as compared with the prior art, and the spindle can be driven stably with less gas consumption.

It is a perspective view which shows the external appearance of an example of a grinding device. It is a perspective view which shows an example of the moving means which comprises a grinding device. It is sectional drawing which shows the structure of a process means schematically.

  A grinding apparatus 1 shown in FIG. 1 is a kind of processing apparatus to which the present invention is applied, and a holding table 2 that holds a workpiece and a processing means 3 that grinds the workpiece held on the holding table 2. And a processing feed means 4 for processing and feeding the processing means 3, and an operation panel 5 for inputting by an operator.

  As shown in FIG. 1, the holding table 2 is rotatably supported by a base 20, and a telescopic bellows 21 is connected to a side portion in the front-rear direction of the base 20. The holding table 2 is configured to move in the horizontal direction and in the front-rear direction (A direction and B direction in FIG. 1) by being driven by the moving means 22 shown in FIG.

  The moving means 22 shown in FIG. 2 has a ball screw 220 having a horizontal rotation axis and extending in the front-rear direction, a pair of guide rails 221 arranged in parallel to the ball screw 220, and a forward and reverse rotation of the ball screw 220. And a sliding portion 223 having a nut (not shown) screwed into the ball screw 222 and having a lower portion slidably contacting the guide rail 221, and driven by the pulse motor 222. As the screw 220 rotates, the sliding portion 223 is guided by the guide rail 221 and slides in the front-rear direction. Further, the holding table 2 is disposed on the upper surface side of the sliding portion 223 via the shaft portion 23, and the holding table 2 is also moved by the movement of the sliding portion 223. In this example, the moving means 22 is configured to move the holding table 2, but the moving means may be configured to move the processing means 3 shown in FIG. 1 in the horizontal direction. That is, the moving means only needs to have a function of relatively moving the processing means 3 and the holding table 2.

  As shown in FIG. 3, the processing means 3 includes a spindle unit 6. The spindle unit 6 includes a columnar main shaft portion 600 and a flange portion 601 that protrudes in the radial direction from the outer peripheral surface of the main shaft portion 600, and includes a spindle 60 having the axis of the main shaft portion 600 as a rotation axis. . The spindle 60 is accommodated in the housing 61. The housing 61 is formed with a main shaft housing portion 610 that houses the main shaft portion 600 and a flange housing portion 611 that is larger in diameter than the main shaft housing portion 610 and houses the flange portion 601. 610 has an inner wall 610a, and the collar part accommodating portion 611 has an inner wall 611a. The spindle 60 is accommodated in the housing 61 in a non-contact state with the inner walls 610 a and 611 a of the housing 61.

  A plurality of air ejection grooves 612 that eject gas (for example, air) toward the axial center of the main shaft portion 600 are formed in the inner wall 610 a of the main shaft portion accommodating portion 610. Each air ejection groove 612 communicates with the air circulation hole 613. The air circulation hole 613 is formed to branch from a gas flow path 62 formed inside the housing 61. The gas flow path 62 communicates with the gas supply source 7. The gas flow path 62 is provided with a gas regulating valve 8 that regulates the flow rate of the gas. The operation of the gas regulating valve 8 is controlled by the gas regulating valve control means 9. From each air ejection groove 612, a gas that is output from the gas supply source 7 and whose flow rate or pressure is adjusted by the gas regulating valve 8 is ejected. A radial air bearing 63 that supports the spindle in a direction perpendicular to the direction of the rotation axis of the spindle 60 is formed by a gas layer formed between the main shaft portion 600 and the inner wall 610a of the housing 61 by gas ejection. Is done.

  The gas channel 62 also communicates with a plurality of air ejection grooves 614 that eject gas in the surface direction of the flange 601 toward the flange 601 via the air circulation holes 615. The plurality of air ejection grooves 614 are formed concentrically around the rotation axis of the spindle 60 on the upper and lower inner walls 611a of the flange housing portion 611, and are respectively formed on both the upper surface and the lower surface of the flange portion 601. Air is spouted out. A thrust air bearing 64 that supports the spindle 60 in the rotation axis direction is formed by a gas layer formed between the flange portion 601 and the inner wall 611a. As described above, the spindle unit 6 includes the spindle 60, the housing 61, the gas flow path 62, the radial air bearing 63, and the thrust air bearing 64.

  A grinding wheel 31, which is a processing tool, is attached to one end of the spindle 60 with a screw 32 via a wheel mount 30. The grinding wheel 31 is configured by fixing a plurality of grinding wheels 311 in an arc shape on the lower surface of the base 310.

  On the other hand, a servo motor 33 that rotationally drives the spindle 60 and the grinding wheel 31 is disposed on the other end side of the spindle 60. The servo motor 33 includes a rotor 330 coupled to the main shaft portion 600 of the spindle 60 and a stator coil 331 disposed on the outer peripheral side of the rotor 330, and applies AC driving power to the stator coil 331. Thus, the rotor 330 is rotated, and the spindle 60 connected to the rotor 330 is rotated.

  Returning to FIG. 1, the processing feed means 4 rotates the ball screw 40 having a vertical axis, a pair of guide rails 41 arranged in parallel with the ball screw 40, and the ball screw 40. A pulse motor 42 and a nut 43 (not shown) that engages with the ball screw 40 are provided inside, and a sliding portion 43 whose side portion is in sliding contact with the guide rail 41 is provided. As the screw 40 rotates, the sliding portion 43 is guided by the guide rail 41 and moves up and down. Since the support portion 44 fixed to the sliding portion 43 supports the processing means 3, the processing means 3 is also raised and lowered by raising and lowering the sliding portion 43.

  Next, the operation of the grinding apparatus 1 when grinding the surface of the workpiece using the grinding apparatus 1 shown in FIG. 1 will be described with reference to FIGS. The workpiece to be ground is not particularly limited. For example, semiconductor wafers such as silicon wafers, semiconductor product packages, ceramics, glass, sapphire (Al2O3) based inorganic material substrates, various electronic components such as LCD drivers, micron, etc. Various processing materials that require machining position accuracy of order, flatness of micron order to submicron order (TTV: total thickness variation: of workpiece ground surface with height measured in thickness direction with workpiece ground surface as reference surface Examples include various processed materials that require a difference between the maximum value and the minimum value on the entire surface.

  A protective tape T is attached to the surface of the workpiece W that is not ground, the protective tape T side is held by the holding table 2, and the ground surface is exposed. 2 is driven by the moving means 22 shown in FIG. 2, the holding table 2 is moved in the direction A shown in FIG. 1, and the workpiece W is positioned below the processing means 3, so that the workpiece W is moved. The grinding surface faces the grinding wheel 311.

  Next, the holding table 2 is rotated, and the processing means 3 in a state in which the grinding wheel 31 is rotated by the drive by the servo motor 33 shown in FIG. 3 is lowered by the processing feeding means 4 so that the rotating grinding wheel 311 is processed. By bringing the object W into contact with the surface to be ground, the surface to be ground is ground. Then, when the workpiece W is formed to a desired thickness, the machining feed means 4 raises the machining means 3 to finish the grinding.

  As shown in FIG. 3, since the spindle 60 is supported by the radial air bearing 63 and the thrust air bearing 64, air is always ejected from the air ejection grooves 612 and 614. The amount or pressure of air ejected from the air ejection grooves 612 and 614 is adjusted by the gas regulating valve 8. The gas regulating valve 8 is controlled by the gas regulating valve control means 9. The gas regulating valve control means 9 can also control the gas regulating valve 8 according to an instruction from the operator based on the input from the operation panel 5 shown in FIG. 1, or automatically gas according to the operation and status of the grinding apparatus 1. The regulating valve 8 can also be controlled.

  While actual grinding is being performed, a large load is applied to the spindle 60 due to contact between the grinding wheel 311 and the surface to be ground of the workpiece W, so that the air ejected from the air ejection grooves 612 and 614 Also, a relatively strong pressure is required. Therefore, the gas regulating valve control means 9 controls the gas regulating valve 8 so that an amount of air that can be appropriately processed even in such a situation can be sent between the spindle 60 and the inner walls 610a and 611a of the housing 61. To do. On the other hand, while grinding is not being performed, the pressure for supporting the spindle 60 is not required to be as high as during grinding, and at least the amount of air that does not allow the spindle 60 to contact the inner walls 610a and 611a of the housing 61 is present. Since the gas adjustment valve control means 9 may be sent between the spindle 60 and the inner walls 610a and 611a of the housing 61, the gas regulating valve control means 9 is configured such that the pressure of the air ejected from the air ejection grooves 612 and 614 is greater than the pressure during grinding. Also, the gas regulating valve 8 is controlled so as to be a low value. Specifically, the pressure of the air ejected from the air ejection grooves 612 and 614 is set to, for example, 0.5 [MPa] during grinding, and set to, for example, 0.3 [MPa] while grinding is not performed. Thus, the air consumption can be reduced to about half. Such control can be performed manually by an operator or automatically without operation by the operator. Note that the time during which the grinding is not being performed is the time during which the grinding is not performed during the warm-up, the standby after the warm-up and before the grinding is started (the number of workpieces to be processed) For example, an interval between the end of grinding of the workpiece and the start of grinding of the next workpiece).

  When the gas regulating valve control means 9 automatically performs control to reduce air consumption while grinding is not being performed, for example, the gas is adjusted according to the value of the drive current of the servo motor 33 shown in FIG. The adjustment valve 8 may be controlled. That is, when the grinding wheel 311 is not in contact with the workpiece, when the load acting on the spindle 60 is small and the drive current supplied to the servo motor 33 is smaller than a predetermined threshold, the gas regulating valve control means 9 performs grinding. It judges that it is not in, and adjusts the gas regulating valve 8 to reduce the pressure of the air ejected from the air ejection grooves 612 and 614. On the other hand, when the drive current is larger than the predetermined threshold, it is determined that grinding is being performed, and the pressure of the air ejected from the air ejection grooves 612 and 614 is increased.

  Further, when the gas regulating valve control means 9 recognizes the vertical position information of the processing means 3 and the processing means 3 is positioned below the predetermined position, it is determined that grinding is in progress and the air ejection grooves 612 and 614 The pressure of the air to be ejected is increased, and when the processing means 3 is positioned above the predetermined position, it is determined that the grinding is not being performed and the pressure of the air ejected from the air ejection grooves 612 and 614 is decreased. Good.

  In the above description, the grinding apparatus has been described. However, the present invention can also be applied to other processing apparatuses having a gas bearing. For example, a cutting blade, which is a processing tool, is attached to one end of a spindle of a spindle unit configured in the same manner as the above grinding apparatus, and the holding table that holds the workpiece and the spindle unit move relatively by driving the moving means. Thus, the present invention is also applied to a cutting apparatus configured to perform cutting. In this case, the workpiece includes, in addition to the workpiece processed in the grinding apparatus, an adhesive member such as DAF (Die Attach Film) provided on the back surface of the wafer for chip mounting.

1: Grinding device 2: Holding table 20: Base 21: Bellows 22: Moving means 220: Ball screw 221: Guide rail 222: Pulse motor 223: Sliding part 23: Shaft part 3: Processing means 30: Wheel mount 31: Grinding wheel (processing tool) 310: base 311: grinding wheel 32: screw 33: servo motor 330: rotor 331: stator coil 4: processing feeding means 40: ball screw 41: guide rail 42: pulse motor 43: sliding part 5: Operation panel 6: Spindle unit 60: Spindle 600: Main shaft portion 601: Gutter portion 61: Housing 610: Main shaft portion accommodation portion 611: Gutter portion accommodation portion 610a: 611a: Inner wall 612: Air ejection groove 613: Air flow hole 614 : Air flow groove 615: Air flow hole 62: Gas flow path 63: Radial air Bearings 64: Thrust air bearing 7: gas supply source 8: gas control valve 9: gas control valve controlling means

Claims (1)

A spindle having a cylindrical main shaft portion and a flange projecting radially from the outer periphery of the main shaft portion, the axis of which is the axis of rotation, a housing for housing the spindle, and the main shaft of the spindle A radial air bearing for supporting the spindle in a direction perpendicular to the direction of the rotation axis, formed by a gas layer formed between the portion and the inner wall of the housing, and the flange portion of the spindle and the inner wall of the housing A thrust air bearing which is formed by a gas layer formed between the spindle and supports the spindle in the direction of the rotation axis; and a gas is fed between the spindle and the inner wall of the housing to provide the radial air bearing and the thrust air. A spindle unit having a gas flow path forming a bearing;
A machining tool attached to the tip of the spindle;
A holding table for holding a workpiece to be processed by the processing tool;
Moving means for relatively moving the spindle unit and the holding table;
A processing apparatus comprising:
A gas regulating valve provided in the gas flow path for adjusting the flow rate of the gas;
When the workpiece is not processed by the processing tool, the gas is fed between the spindle and the inner wall of the housing in such an amount that the main shaft portion and the flange portion of the spindle do not contact the inner wall of the housing. The gas regulating valve is controlled so that when the workpiece is machined by the machining tool, the gas regulating valve is fed between the spindle and the inner wall of the housing in an amount capable of performing an appropriate machining. Gas regulating valve control means for controlling;
A processing apparatus having

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