JP2012501538A - Pick and place machine - Google Patents

Abstract

A turret having a frame including an axis, a plurality of pick / place heads and an inertia balance wheel, and both the pick / place head and the inertia balance wheel are mounted to rotate around the axis of the axis And a first electromechanical device for rotating the turret during the pick-and-place operation, comprising a magnetic field generation unit and an energization unit, a part on the turret and a part on the inertia balance wheel A pick and place machine with a first electromechanical device, wherein the torque generated by the first electromechanical device causes angular acceleration of the turret in one direction and counteracts angular acceleration of the inertial balance wheel Pick and place machine configured to cause in direction.
[Selection] FIG. 2 (a), FIG. 2 (b)

Description

  The present invention relates to pick-and-place machines, particularly but not exclusively, for three-dimensional integrated circuits (3DICs).

  It is well known that pick and place machines are used to place various electronic components on a substrate such as a printed circuit board or lead frame. The pick and place performance provided by existing technology is either high speed or high accuracy, not both. One type of pick and place machine comprises a rotatable turret with multiple pick / place heads. An example of this is disclosed in German Offenlegungsschrift 10230901.

  With the advent of 3DIC, it has become necessary to place multiple dies on a 3D stack. This placement requires extremely high accuracy, and in some applications, the acceptable placement error needs to be less than 1 micrometer, for example.

  An object of the present invention is to provide a pick-and-place machine capable of placing components with high accuracy, for example, with accuracy that satisfies the needs of 3DIC manufacturing and at a profitable price.

Based on this point, according to the first aspect, the present invention provides:
A frame containing the axis;
A turret having a plurality of pick / place heads and an inertia balance wheel, wherein both the pick / place head and the inertia balance wheel are mounted to rotate about an axis of the shaft;
A first electromechanical device for rotating a turret during pick-and-place operation, comprising a magnetic field generator and a current-carrying part, a part on the turret and a part on an inertia balance wheel 1 electromechanical device;
With
There may be provided a pick and place machine configured such that the torque generated by the first electromechanical device causes angular acceleration of the turret in one direction and angular acceleration of the inertia balance wheel in the opposite direction.

  During the pick and place operation, the turret is initially angularly positive and then negatively angularly accelerated during each pick / place operation. The first aspect of the invention prevents or at least significantly reduces the transmission of reaction forces to the frame caused by angular acceleration of the turret by providing an inertial balance wheel. This is caused by a reaction force that angularly accelerates in the opposite direction to the turret. This eliminates frame vibrations or keeps them at least low, even when the pick and place machine is operating at high speed, i.e. when positive and negative high-angle acceleration is required. Therefore, high placement accuracy can be achieved.

  Preferably, the turret is rotatable so that each pick / place head can be moved to the pick position and place position, each pick / place head comprising a translation of the actuator, and the pick and place machine is in the pick position. An actuator stator portion arranged and fixed to the frame, and an actuator stator portion arranged at the place position and fixed to the frame, the pick and place machine has the pick / place head at the pick or place position. At some point, an actuating actuator is configured that is operable to perform a pick or place movement.

  By fixing the stator portion of the actuator to the frame, the reaction force generated during the execution of the pick or place movement is transmitted to the frame, thereby avoiding the vibration of the turret.

  Preferably, the drive shaft is horizontal, and the pick and place machine further includes a pick stage disposed on one side of the turret and a place stage disposed on the opposite side of the turret, and both stages have substrates in a vertical plane shape. Configured to hold on.

  Such an orientation is effective to reduce the ease of attachment of contaminants to the substrate or to the die surface.

  Conveniently, the pick and place machine further comprises a blowing means for directing a clean air flow downward across the surface of the pick stage and place stage to further assist in eliminating contaminants.

According to a second aspect, the present invention provides:
A frame containing the axis;
A turret with a plurality of pick / place heads, each pick / place head having a translation part of the actuator, so that each pick / place head can be moved between a pick position and a place position by rotating the turret. A turret mounted to rotate around the axis of the shaft;
A pick-and-place machine with
When the pick / place head is in the pick or place position, the actuator further includes: a stator portion of the actuator arranged at the pick position and fixed to the frame; and an actuator stator portion arranged at the place position and fixed to the frame. A pick and place machine configured to form an actuating actuator operable to perform pick or place movement may be provided.

According to a third aspect of the present invention, the present invention provides:
A frame containing a horizontally oriented axis;
A turret having a plurality of pick / place heads and mounted to rotate about the axis of the shaft;
A pick stage located on one side of the turret, a place stage located on the opposite side of the turret,
A pick-and-place machine with
Both stages can provide a pick and place machine configured to hold the substrate in a vertical plane.

According to a fourth aspect, the present invention is a turret assembly for a pick and place machine,
A turret having a plurality of pick / place heads and an inertia balance wheel, wherein both the pick / place head and the inertia balance wheel can be mounted so as to rotate around the axis of the support frame;
A first electromechanical device for rotating a turret during pick-and-place operation, comprising a magnetic field generator and a current-carrying part, a part on the turret and a part on an inertia balance wheel 1 electromechanical device;
A turret assembly comprising
A turret assembly may be provided that is configured such that the torque generated by the first electromechanical device causes angular acceleration of the turret in one direction and angular acceleration of the inertial balance wheel in the opposite direction.

  As used herein, the term “angular acceleration” is used broadly to include both angular acceleration and angular deceleration. Angular acceleration is referred to as positive angular acceleration, and angular deceleration is referred to as negative angular acceleration.

  Other aspects and further preferred features of the invention are described in the following description and defined in the appended claims.

  In the following, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 shows a schematic front view of a first pick and place machine. FIG. FIG. 2 shows a cross-sectional view of the turret assembly shown in FIG. FIG. 2 shows an axial cross-sectional view of the turret assembly shown in FIG. A schematic block diagram of a second pick and place machine is shown. Figure 4 shows a schematic of each part of an individual pick / place head when reaching a pick or place position. Figure 2 shows a schematic of each part of an individual pick / place head in a pick or place position.

  A first pick and place machine, indicated generally by the reference numeral 10, is shown in FIG. The pick and place machine 10 comprises a support frame 12 and a turret assembly for rotation about a shaft 15 (visible in FIGS. 2 (a) and 2 (b)) having an axis indicated by reference symbol X. 14 is attached to the support frame 12. The pick and place machine 10 further includes a pick stage 16 fixed to the frame 12 on the right side of the turret assembly 14 and a place stage 18 fixed to the frame 12 on the left side of the turret assembly 14. The pick stage 16 comprises a substrate in the form of a pick wafer 16a that contains an array of dies ready for placement. The pick stage 16 can adjust the position of the pick wafer 16a two-dimensionally in the plane of the wafer. The place stage 18 includes a substrate 18a that holds a die during lamination. The place stage 18 can adjust the position of the substrate 18a two-dimensionally within the plane of the substrate 18a. The pick and place machine 10 further includes a downflow unit 26 for sending a clean air flow downward across the surfaces of the pick stage 16 and the place stage 18. The air stream is filtered and has a very low ISO cleanliness class. The turret assembly 14 includes a turret 20 having a turret body 22 in the form of a thick annular ring, with eight pick / place heads 24a-h disposed at equal angular intervals around the turret body 22. Each pick / place head 24 includes a vacuum nozzle that is movable radially between an extended position and a retracted position to perform pick or place movement.

  Referring to FIG. 2 (b), the turret assembly 14 further includes an inertia balance wheel 30 attached around the shaft 15. The inertia balance wheel 30 takes the form of a thick annular ring having approximately the same dimensions and mass as the turret body 22. Both the turret 20 and the inertia balance wheel 30 are rotatably mounted around the shaft 15 by an air bearing 25.

  In other embodiments, rolling element bearings can be used instead.

  The turret assembly 14 further includes a first electromechanical device 40 including a magnetic field generator 42 fixed to the turret main body 22 and an energization unit 44 fixed to the inertia balance wheel. The magnetic field generator 42 includes twelve permanent magnets 42a to 42l placed at equal angular intervals around the turret body 22, as best seen in FIG.

  The energization unit 44 includes twelve coils 44 a to l corresponding to the permanent magnets 42 a to l that are placed around the inertia balance wheel 30 at equal angular intervals. The electromechanical device 40 can also be thought of as a linear motor whose constituent elements are bent into a circle around the axis X. The electromechanical device 40 serves to rotate the turret 20 during pick and place operations.

  In other embodiments, the energization unit 44 is fixed to the turret body 22, and the magnetic field generation unit 42 is fixed to the inertia balance wheel 30. In other embodiments, the first electromechanical device 40 may include an induction motor or an asynchronous motor. In this case, the magnetic field generation unit 42 may include a plurality of coils that generate a magnetic field, and the energization unit 44 may include a conductor that generates an eddy current inside. The conductor may comprise a cylinder or may have a cage configuration.

  In operation, the turret 20 is rotated counterclockwise using an indexing motion as shown in FIG. When stopped, the pick / place head in the pick position, corresponding to the pick / place head 24c of FIG. 1, picks up a die (not referenced) from the pre-positioned pick wafer 16a. At the same time, the pick / place head in place, corresponding to the pick / place head 24a of FIG. 1, places the die on the pre-positioned substrate 18a. In addition to vertical orientation of the pick wafer 16a and substrate 18a, providing a clean air flow from the downflow unit 26 helps to prevent contaminant buildup on the surface of the die. It is understood that by creating a clean environment inside the pick and place machine 10, particularly in the pick stage 16 and place stage 18, it is possible to place the pick and place machine 10 in an environment where the cleanliness is less severe. It will be. When the turret 20 is indexed to the next pick / place position, i.e., the position where the pick / place head 24f is the pick position and the pick / place head 24b is the place position, the positive angular acceleration of the turret 20 is first applied. The electromechanical device 40 is driven so as to generate torque that is caused in the counterclockwise direction. When the maximum angular velocity is reached, torque is generated in the opposite direction to cause negative angular acceleration of the turret 20 in the counterclockwise direction. As a result, the turret 20 stops at the next pick / place position. Since the inertia balance wheel 30 is rotatably attached to the shaft 15, the reaction force from the angular acceleration necessary for rotating the turret 20 by the above method is not transmitted to the frame 12, but is transmitted to the inertia balance wheel 30 instead. Therefore, the angular acceleration of the inertial balance wheel 30 in the clockwise direction is caused.

  This eliminates the vibration of the frame 12 or keeps it at least low, even when the pick and place machine 10 is operating at high speed, i.e. when high positive and negative acceleration is required. Therefore, high placement accuracy can be achieved.

  Hereinafter, the same reference numerals are used to refer to the same parts as those described with reference to the first pick-and-place machine shown in FIGS. 1, 2 (a), and 2 (b).

  FIG. 3 shows a second pick and place machine 10. To simplify the drawing, most of the frame 12, pick / place head 24, and pick and place stages 16, 18 are not shown. The turret assembly 14 shown in FIG. 3 is different from that of the first pick-and-place machine in that the turret 20 is directly attached to the outer periphery of the inertia balance wheel 30 via the air bearing 25.

  The pick and place machine 10 includes a control system 50 that includes a turret position control feedback loop 52. The control loop 52 comprises means 54 for setting the desired turret position and a comparator 56 that compares the desired turret position with the actual turret position signal supplied from the transducer 60 to generate an error signal. This error signal is supplied to the loop control unit 62, and the loop control unit 62 supplies the control signal to the drive unit 64 that drives the electromechanical device 40. Transducer 60 optically measures the position of turret 20 relative to the fixed world by an index on axis 15. This index either represents the position directly or is used to estimate the angular velocity, which is then used to calculate the position.

  In operation, the second pick and place machine 10 operates like a first pick and place machine. A signal indicating the next pick / place position is provided from the means 54. The turret 20 is indexed to that position by the action of the control loop 52. Also in this case, if torque that angularly accelerates the turret 20 in the clockwise direction is generated in the electromechanical device 40, the inertia balance wheel 30 rotates in the opposite direction due to the reaction force. This eliminates the vibration of the frame 12 or keeps it at least low, so that high placement accuracy can be achieved.

  The control system 50 can also be incorporated into the first pick and place machine.

  In practice, the inertial balance wheel 30 may not stop during operation. For this reason, the second pick and place machine 10 preferably comprises means for reducing the angular velocity of the inertia balance wheel 30 that is coupled between the inertia balance wheel 30 and the shaft 15. In one embodiment, this is achieved by passive damping means that induce eddy currents, such as an array of magnets disposed on the inertial balance wheel 30 and a coating of conductive metal on the turret 20. The magnet arrangement and the conductive metal coating position may be reversed. In another embodiment, a second electromechanical device similar to the first electromechanical device 40 is distributed over the inertial balance wheel 30 and the shaft 15, i.e. a portion is disposed on the inertial balance wheel 30, and The part can be arranged on the shaft 15. This second electromechanical device is used to actively control the angular velocity of the inertial balance wheel 30 by a feedback control loop similar to the control loop 52. The active control loop is advantageous in that the damping applied to the inertial balance wheel 30 can be adjusted. When performing critical processing, the damping between the inertial balance wheel 30 and the shaft 15 should be as small as possible. The reason is that when damping is applied, a reaction force partially transmitted to the shaft causes vibration in the frame.

  Various means for reducing the angular speed of the inertial balance wheel can also be incorporated into the first pick and place machine.

  Both the center of the turret 20 and the shaft 15 are preferably hollow. This allows the inertia of the movement to be kept low and creates space for other components such as cable feedthroughs and sensors.

  4 (a) and 4 (b) show the various parts that make up the actuator for moving the nozzle of the pick / place head 24 radially between the retracted and extended positions. The configuration shown is suitable for incorporation into either the first or second pick and place machine.

  The frame 12 of the pick and place machine 10 supports the stator portion 72 of the actuator 70 at the pick position and the place position. 4A and 4B only show place positions. The stator portion 72 includes a housing portion 74, and a coil assembly 76 is provided inside the housing portion 74. The stator portion 72 further includes a coupling portion 77 that firmly fixes the housing portion 74 to the frame 12. Each pick / place head 24 includes a translation section 80 that includes a permanent magnet assembly 82 and an actuator member 84 that is mounted to move radially inward and outward. For clarity of illustration, the attachment of the outer end of member 84a to the nozzle is omitted.

  During operation, when the pick / place head 24 moves to the place position as shown in FIG. 4 (a) and reaches the stop position in FIG. 4 (b), the stator 72 and the pick arranged at the place position are picked. The actuating actuator is formed by aligning with the translation unit 80 carried by the place head 24. At this position, the magnet assembly 82 is located in the functional region of the coil assembly 76, and therefore, between the position where the parallel moving portion 80 is contracted in the radial direction and the position where the parallel movement portion 80 is extended in order to perform the mounting operation. The actuator 70 can be controlled by the current supplied to the coil assembly 76 so as to move in the axial direction. When the translation unit 80 moves, the reaction force is transmitted to the frame / fixed world via the stator unit 72. Since this reaction force is transmitted to the frame / fixed world, there is no disturbance of the turret 20. Since the turret 20 carries the nozzle, there is no disturbance / vibration on the turret 20, so that the positioning accuracy is improved.

  One advantage of this embodiment of the present invention is that there is no need to attach an electrical cable to the turret 20 to drive the nozzle activation. However, for example, several cables may be required for measurement. Furthermore, by carrying only a part of the actuator 70 on the turret 20, the total mass of the turret 20 can be kept low, which can increase the throughput or improve the mounting accuracy (depending on which is necessary). Will be understood.

Claims (15)

A frame containing the axis;
A turret comprising a plurality of pick / place heads and an inertia balance wheel, wherein both the pick / place head and the inertia balance wheel are mounted to rotate about an axis of the axis;
A first electromechanical device for rotating the turret during a pick-and-place operation, comprising a magnetic field generator and a current-carrying part, part on the turret and part on an inertia balance wheel A first electromechanical device;
With
A pick-and-place machine configured such that the torque generated by the first electromechanical device causes angular acceleration of the turret in one direction and angular acceleration of the inertia balance wheel in the opposite direction.   The pick and place machine according to claim 1, wherein the turret and the inertia balance wheel are directly attached to the shaft.   The pick and place machine according to claim 1, wherein the turret is attached to an outer periphery of the inertia balance wheel, and the inertia balance wheel is directly attached to the shaft.   The turret is rotatable so that each pick / place head can be moved to a pick position and a place position, each pick / place head is provided with a translation part of an actuator, and the pick and place machine is at the pick position. An actuator stator portion disposed and fixed to the frame; and an actuator stator portion disposed at the place position and fixed to the frame. The pick and place machine includes the pick / place head. A pick and place machine according to any preceding claim, wherein an actuating actuator is formed that is operable to perform a pick or place movement when placed in the pick or place position.   The drive shaft is horizontal, and the pick and place machine further includes a pick stage placed on one side of the turret and a place stage placed on the opposite side of the turret, The pick and place machine according to any one of the preceding claims, wherein the pick and place machine is configured to hold the substrate in a vertical plane.   The pick and place machine according to any one of the preceding claims, further comprising air blowing means for sending a clean air flow downward to the entire surface of the pick stage and the place stage.   The pick and place machine according to any one of the preceding claims, further comprising a first feedback control loop for controlling the position of the turret.   The pick and place machine according to any one of the preceding claims, further comprising means for passively attenuating an angular velocity of the inertia balance wheel.   A second electric machine device including a magnetic field generation unit and an energization unit, a part of which is on the inertia balance wheel and a part of which is on the shaft; and an angular velocity of the inertia balance wheel is set to the second electric machine. The pick and place machine according to any one of claims 1 to 7, further comprising a second feedback control loop for controlling by the device.   The pick and place machine of claim 9, wherein the second feedback control loop may be used to selectively dampen rotation of the inertial balance wheel.   The pick and place machine according to any one of the preceding claims, wherein the turret is hollow.   The pick and place machine according to any one of the preceding claims, wherein the shaft is hollow. A turret assembly suitable for use in a pick and place machine according to any one of the preceding claims,
A turret comprising a plurality of pick / place heads and an inertia balance wheel, wherein both the pick / place head and the inertia balance wheel can be mounted to rotate about an axis of a support frame axis;
A first electromechanical device for rotating the turret during a pick-and-place operation, comprising a magnetic field generation unit and an energization unit, a part on the turret and a part on the inertia balance wheel A first electromechanical device in
With
The torque generated by the first electromechanical device is configured to cause angular acceleration of the turret in one direction and angular acceleration of the inertia balance wheel in the opposite direction. A frame containing the axis;
A turret having a plurality of pick / place heads, wherein each pick / place head includes a translation part of an actuator, and the pick / place head can be moved between a pick position and a place position by rotating the turret. A turret mounted to rotate around the axis of the shaft;
A pick-and-place machine with
A stator portion of an actuator arranged at the pick position and fixed to the frame; and a stator portion of an actuator arranged at the place position and fixed to the frame, wherein the pick / place head is the pick or place head A pick and place machine configured to form an actuating actuator operable to perform a pick or place movement when placed in a place position. A frame containing a horizontally oriented axis;
A turret comprising a plurality of pick / place heads and mounted for rotation about an axis of said axis;
A pick stage disposed on one side of the turret; a place stage disposed on the opposite side of the turret;
With
Both stages were configured to hold the substrate in a vertical plane,
Pick and place machine.

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