JP2012161861A - Processing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing machine that can perform higher accurate positioning by using a relatively inexpensive mechanism.SOLUTION: The processing machine comprises a movable part, a moving means including a motor for moving the movable part and a ball screw, and a control means for controlling the moving means. The processing machine also includes a simplified scale unit. The control means includes a rotation angle storage part 72 which rotates the motor at prescribed timing and stores a rotation angle of the motor when the movable part is moved to the terminal point from the starting point of a reference distance, a unit rotation angle moving distance calculation part 74 which calculates the moving distance of the movable part per unit rotation from the stored rotation and the reference distance, a rotation angle calculation part 76 which calculates the rotation angle of the motor necessary for moving the movable part by the prescribed distance on the basis of a moving distance per unit rotation calculated by the unit angle rotation moving distance calculation part 74, and a motor control part 78 which moves the movable part by the prescribed distance by rotating the motor by the rotation angle calculated by the rotation angle calculation part 76.

Description

  The present invention relates to a processing apparatus such as a cutting apparatus or a laser processing apparatus having a simple scale.

  In the semiconductor device manufacturing process, a plurality of regions are defined by dividing lines called streets formed in a lattice shape on the surface of a semiconductor wafer such as a silicon wafer or a gallium arsenide wafer having a substantially disk shape. A device such as an IC or LSI is formed in the region. The semiconductor wafer is divided into individual devices by a cutting device or a laser processing device, and the divided devices are widely used in various electric devices such as mobile phones and personal computers.

  The cutting apparatus includes a chuck table that holds a semiconductor wafer, a cutting unit (cutting means) that rotatably supports a cutting blade that cuts the wafer held by the chuck table, and a process that feeds the chuck table in the X-axis direction. Feeding means and indexing feeding means for indexing and feeding the cutting unit in the Y-axis direction are provided, and the wafer can be divided into individual devices with high accuracy.

  On the other hand, the laser processing apparatus includes a chuck table for holding a wafer such as a semiconductor wafer or an optical device wafer, a laser beam irradiation unit for irradiating a wafer held on the chuck table with a pulsed laser beam, and a chuck table in the X-axis direction. Processing feed means for processing feed and index feed means for indexing and feeding the chuck table in the Y-axis direction are provided.

  In the cutting machine, the planned dividing line is indexed and fed in the Y-axis direction while cutting the planned dividing line with the cutting blade, so that the low expansion is achieved in order to achieve high-precision positioning in the Y-axis direction. A linear scale unit composed of a linear scale formed of glass or the like and a reading head is mounted so as to extend in the Y-axis direction.

  In the laser processing apparatus, in addition to the linear scale unit for index feed in the Y-axis direction, positioning of the laser beam irradiation unit with respect to the wafer held on the chuck table in the X-axis direction is also important. In order to realize accurate positioning, a linear scale unit is mounted so as to extend in the X-axis direction.

  Since the processing feed means and the index feed means are generally composed of a combination of a ball screw and a pulse motor, the ball screw is thermally expanded due to a change in room temperature or a change in temperature inside the apparatus accompanying the start-up of the apparatus. Therefore, a linear scale unit is provided in order to correct thermal expansion and realize highly accurate positioning.

Japanese Patent Laid-Open No. 62-173147

  The linear scale unit is composed of a linear scale formed of low expansion glass or the like and a read head, and is very expensive. Therefore, there is a demand for realizing high-precision positioning with an inexpensive mechanism without mounting a linear scale unit.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a machining apparatus that can realize highly accurate positioning by a relatively inexpensive mechanism.

  According to the present invention, there is provided a processing apparatus including a movable part, a moving means including a motor for moving the movable part and a ball screw, and a control means for controlling the moving means, wherein the movable part is a reference distance. A simple scale unit that detects the movement from the start point to the end point, and the control means rotates the motor at a predetermined timing to move the movable part from the start point to the end point of the reference distance. A rotation angle storage unit that stores the rotation angle of the motor, and a unit rotation angle movement distance calculation unit that calculates a movement distance of the movable unit per unit rotation from the rotation angle stored in the rotation angle storage unit and the reference distance And a rotation angle calculation unit for calculating a rotation angle of the motor necessary to move the movable unit by a predetermined distance based on the movement distance per unit rotation calculated by the unit rotation angle movement distance calculation unit, Calculated by the rotation angle calculator Processing apparatus is provided which comprises and a motor control unit for the predetermined distance moves the movable portion by rotating the motor by the rotation angle is, the.

  Preferably, the simple scale unit has a first slit and a second slit spaced apart from the first slit by a reference distance, and is opposed to the base with the simple scale attached to the movable part and the simple scale interposed therebetween. It is comprised from the photo interrupter which consists of the arrange | positioned light emitting element and light receiving element.

  The processing apparatus of the present invention includes a simple scale unit including a relatively inexpensive mechanism for detecting a reference distance. The simple scale unit detects the movement of the reference distance of the movable part, and the movable part is the reference distance. The movement distance per unit rotation is calculated from the rotation angle of the motor at the time of movement.

  When the movable part is moved by a predetermined distance, the rotation angle of the motor to be rotated is calculated from the movement distance per unit rotation angle and the movable part is moved. However, precise positioning is possible.

It is a perspective view of the cutting device concerning the embodiment of the present invention. It is a perspective view of the semiconductor wafer supported by the annular frame via the dicing tape. It is a principal part top view of the cutting device shown in FIG. It is a principal part side view of the cutting device shown in FIG. It is a block diagram of a control means.

  Hereinafter, a cutting device 2 according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration diagram of the cutting device 2. The cutting device 2 includes a pair of guide rails 6 that are mounted on a stationary base (base) 4 and extend in the X-axis direction.

  The X-axis moving block 8 is moved in the machining feed direction, that is, the X-axis direction by an X-axis feed mechanism (machining feed means) 14 composed of a ball screw 10 and a pulse motor 12. A chuck table 20 is mounted on the X-axis moving block 8 via a cylindrical support member 22.

  The chuck table 20 has a suction part (suction chuck) 24 formed of porous ceramics or the like. A plurality of (four in this embodiment) clamps 26 for clamping the annular frame F shown in FIG. 2 are disposed on the chuck table 20.

  As shown in FIG. 2, the first street S1 and the second street S2 are formed orthogonal to each other on the surface of the semiconductor wafer W to be processed by the cutting apparatus 2, and the first street S1 A number of devices D are formed in a region partitioned by the second street S2.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer periphery of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the annular frame F via the dicing tape T, and the annular frame F is clamped by the clamp 26 shown in FIG.

  A pair of guide rails 28 extending in the Y-axis direction are further fixed on the stationary base 4. The Y-axis moving block 30 is moved in the Y-axis direction by a Y-axis feed mechanism (index feed means) 36 composed of a ball screw 32 and a pulse motor 34.

  The Y-axis moving block 30 is formed with a pair of guide rails 38 (only one is shown) extending in the Z-axis direction. The Z-axis moving block 40 is moved in the Z-axis direction by a Z-axis feed mechanism 44 composed of a ball screw (not shown) and a pulse motor 42.

  Reference numeral 46 denotes a cutting unit (cutting means), and a spindle housing 48 of the cutting unit 46 is inserted into and supported by the Z-axis moving block 40. A spindle 49 (see FIGS. 3 and 4) is accommodated in the spindle housing 48, and is rotatably supported by an air bearing. The spindle 49 is rotationally driven by a motor (not shown) housed in a spindle housing 48, and a cutting blade 50 is detachably attached to the tip of the spindle 49.

  An alignment unit (alignment means) 52 is mounted on the spindle housing 48. The alignment unit 52 has an imaging unit (imaging means) 54 that images the wafer W held on the chuck table 20. The cutting blade 50 and the imaging unit 54 are arranged in alignment in the X-axis direction.

  A frame body 58 is attached to the Y-axis moving block 30, and a simple scale 60 is attached to the frame body 58. The simple scale 60 is formed of a zero expansion glass bar or a low expansion glass bar, and at least one surface thereof is provided with a metal plating 62 to prevent light transmission as shown in FIG. The material constituting the simple scale 60 can be formed from a material with low thermal expansion, such as a low expansion ceramic or a low expansion metal, in addition to zero expansion glass or low expansion glass.

  The simple scale 60 has a first slit 64a and a second slit 64b, and the distance between the inner edge of the first slit 64a and the inner edge of the second slit 64b is set to the reference distance L1.

  As shown in FIGS. 1 and 3, the light emitting element 66 and the light receiving element 68 are arranged on the stationary base 4 with the simple scale 60 interposed therebetween. The light emitting element 66 and the light receiving element 68 constitute a photo interrupter. The simple scale unit 65 that detects the reference distance is configured by the simple scale 60 and the photo interrupter including the light emitting element 66 and the light receiving element 68.

  The light emitting element 66 is connected to the control means 70 via a drive circuit (not shown), and the light receiving element 68 is also connected to the control means 70. An electric signal photoelectrically converted by the light receiving element 68 is input to the control means 70. The pulse motor 34 of the Y-axis feed mechanism 36 is also connected to the control means 70.

  As shown in the block diagram of FIG. 5, the control means 70 stores the rotation angle of the pulse motor 34 when the pulse motor 34 is rotated to move the Y-axis moving block 30 by the reference distance L1 in the Y-axis direction. An angle storage unit 72 and a unit rotation angle movement distance calculation unit 74 that calculates the movement distance of the Y-axis movement block 30 per unit rotation based on the rotation angle stored in the rotation angle storage unit 72 and the reference distance L1 are provided. is doing.

  The control means 70 further calculates the rotation angle of the pulse motor 34 necessary for moving the Y-axis movement block 30 by a predetermined distance based on the movement distance per unit rotation angle calculated by the unit rotation angle movement distance calculation unit 74. And a motor control unit 78 that rotates the pulse motor 34 by the rotation angle calculated by the rotation angle calculation unit 76 and moves the Y-axis moving block 30 by a predetermined distance.

  Hereinafter, the operation of the cutting device 2 having the above-described configuration will be described. Usually, when the cutting device 2 is started up, an idling operation for a predetermined time is performed while supplying cutting water. After performing idling operation for a sufficient time, the pulse motor 34 of the Y-axis feed mechanism 36 is rotated at a predetermined timing, and the Y-axis moving block 30, that is, the cutting unit 46 is moved in the Y-axis direction. The simple scale unit 65 including a photo interrupter including a light emitting element 66 and a light receiving element 68 detects the movement of the reference distance L1 of the cutting unit 46, and the pulse motor 34 when the movement of the reference distance L1 is detected. Are stored in the rotation angle storage unit 72 of the control means 70.

  In the illustrated embodiment, as shown in FIG. 4, the reference distance L1 is defined by the inner edge of the first slit 64a and the inner edge of the second slit 64b, so that the light receiving element 68 transmits the first slit 64a. The detected light from the light emitting element 66 is temporarily detected, and the rotation angle storage unit 72 stores the rotation angle of the pulse motor 34 from when this detection is interrupted until the light from the light emitting element 66 is detected through the second slit 64b. .

  Next, based on the rotation angle stored in the rotation angle storage unit 72 and the reference distance L1, the movement distance of the cutting unit 46 per unit rotation is calculated by the unit rotation angle movement distance calculation unit 74. Based on the movement distance per unit rotation angle calculated by the unit rotation angle movement distance calculation unit 74, a pulse motor necessary to move the cutting unit 46 by a predetermined distance, for example, the interval between the adjacent first streets S1. The rotation angle calculation unit 76 calculates the rotation angle 34.

  In the motor control unit 78, the pulse motor 34 is rotated by the rotation angle calculated by the rotation angle calculation unit 76, and the cutting unit 46 is indexed and fed by a predetermined distance, for example, the pitch of the first street S1.

  In the embodiment described above, the rotation angle of the pulse motor 34 when the cutting unit 46 is moved in the Y-axis direction by the reference distance L1 by the relatively inexpensive simple scale unit 65 including the simple scale 60 and the photo interrupter. When the moving distance per unit rotation of the pulse motor 34 is calculated from the above and the cutting unit 46 is moved by a predetermined distance, the rotation angle of the pulse motor 34 to be rotated is calculated from the moving distance per unit rotation to calculate the cutting unit 46. Therefore, the cutting unit 46 can be precisely positioned even if the temperature changes in the room temperature or inside the apparatus.

  In the embodiment described above, the cutting unit 46 constitutes the movable part. However, in the laser processing apparatus, the laser beam irradiation unit or the chuck table unit having the chuck table constitutes the movable part.

2 Cutting device 20 Chuck table 30 Y-axis moving block 34 Pulse motor 36 Y-axis moving mechanism 46 Cutting unit (cutting means)
50 Cutting blade 60 Simple scale 64a First slit 64b Second slit 65 Simple scale unit 66 Light emitting element 68 Light receiving element 70 Control means

Claims (2)

A processing apparatus comprising a movable part, a moving means including a motor and a ball screw for moving the movable part, and a control means for controlling the moving means,
A simple scale unit for detecting that the movable part has moved from the start point to the end point of the reference distance;
The control means rotates the motor at a predetermined timing to store the rotation angle of the motor when the movable part is moved from the start point to the end point of the reference distance;
A unit rotation angle movement distance calculation unit for calculating a movement distance of the movable unit per unit rotation from the rotation angle stored in the rotation angle storage unit and the reference distance;
A rotation angle calculation unit for calculating a rotation angle of the motor necessary to move the movable unit by a predetermined distance based on the movement distance per unit rotation calculated by the unit rotation angle movement distance calculation unit;
A motor control unit that rotates the motor by the rotation angle calculated by the rotation angle calculation unit and moves the movable unit by the predetermined distance;
The processing apparatus characterized by including. The simple scale unit has a first slit and a second slit that is spaced from the first slit by a reference distance, and is attached to the movable part.
The processing apparatus according to claim 1, comprising a photointerrupter including a light emitting element and a light receiving element disposed so as to face each other with the simple scale interposed therebetween.

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