JP4722117B2 - Wire bonding equipment - Google Patents

Description

  The present invention relates to a wire bonding apparatus, and more specifically, when performing wire bonding using a large-diameter bonding wire, it is possible to maintain a predetermined pressure for the bonding wire during bonding. The present invention relates to a wire bonding apparatus.

The diameter of the bonding wire used for general wire bonding connection is often about 30 μm. In such a wire bonding apparatus using a bonding wire having a general thickness, the loop length of the trapezoidal loop, the bonding step, and the semiconductor chip and lead frame electrode position data and the semiconductor chip shape data are used. A calculation unit that calculates the trapezoidal length, and a reverse amount, a reverse height, and a Z increase amount of the capillary movement trajectory using these calculated values as a function, and these calculated values are sent to the XYZ control unit. An apparatus of a form that controls the operation of a capillary by three-dimensional coordinates has already been provided, such as a wire bonding apparatus (see Patent Document 1) including a function calculation unit for inputting.
Japanese Patent No. 2883463

  In recent years, semiconductor devices have come to be frequently used as parts for automobile electrical equipment. In semiconductor devices mounted on automobiles, so-called power devices such as power transistors are often connected by wire bonding. Some bonding wires used for such high power consuming articles have a diameter of about 500 μm. In such a bonding wire, the amount of change in the height position of the bonding tool is about 200 μm between the contact with the bonding surface and the completion of bonding, and the change in the pressure applied from the bonding tool to the bonding surface is the conventional one. There is a problem that it is much larger than the wire bonding, and the influence on the quality of the product that has been connected by wire bonding cannot be ignored.

  In the conventionally proposed wire bonding apparatus including the above-mentioned Patent Document 1, the operation of the capillary is controlled by three-dimensional coordinates. There is no control, and there is a strong demand for a wire bonding apparatus capable of controlling the applied pressure during bonding.

  Accordingly, the present invention provides a wire bonding apparatus using a so-called large-diameter bonding wire (having a diameter size of 100 μm or more), and applies a pressure applied to the bonding surface by a bonding tool from the start of bonding to the end of bonding. An object of the present invention is to provide a wire bonding apparatus capable of maintaining a predetermined pressure.

  The present invention provides a bonding tool for connecting a bonding wire to a workpiece, an ultrasonic horn for holding the bonding tool at a tip, a support arm to which the ultrasonic horn is attached, and a base of the support arm that can be rotated. A support unit connected to the support unit, a drive unit that is fixed to the support unit, tilts the support arm with a connection part of the support unit as a support shaft, and pressurizes the bonding tool to the workpiece, and one end portion is a fixed end A plate spring that is attached to the support arm, the other end is connected to the drive means as a free end, and is displaced according to a driving force by the drive means, and a free end of the plate spring that is attached to the support arm A position detector for detecting the position of the position detector attached to the side, and based on the position information of the position detector detected by the position detector. A pressing force calculating means for calculating a pressing force by which the bonding tool presses the bonding surface; a driving force control means for controlling the driving force of the driving means based on the pressing force calculated by the pressing force calculating means; The driving force control means includes a period from the time when the pressure applied to the bonding surface by the bonding tool reaches a predetermined pressure after the bonding tool contacts the bonding surface to the time when the wire bonding is completed. In the meantime, the wire bonding apparatus is characterized in that the driving force of the driving means is controlled so that the pressing force of the bonding tool is maintained at the predetermined pressing force.

The support may be provided with contact state detection means for detecting a state in which the bonding tool is in contact with the bonding surface.
Further, the contact state detection means is capable of adjusting a detection position of the contact state.
Accordingly, it is possible to accurately detect that the bonding tool has come into contact with the bonding surface, and it is possible to control the pressure applied to the bonding surface by the bonding tool at an appropriate timing.

  Further, the support is provided with a stopper for regulating a tilting range of the support arm. Accordingly, the upper limit value of the pressure applied to the bonding surface by the bonding tool can be mechanically limited, which is suitable as a backup for the driving force control means.

  The bonding wire has a diameter of 100 to 500 μm. The present invention can be applied particularly effectively to such a thick bonding wire.

According to the wire bonding apparatus according to the present invention, when wire bonding connection is performed using a so-called large-diameter bonding wire having a diameter of 100 μm or more, the bonding tool is associated with a change in the height position of the bonding tool during wire bonding. It is possible to prevent a change in the pressure applied to the bonding surface.
In addition, large-diameter bonding wires can be bonded while maintaining an appropriate pressure on the bonding surface, enabling high-quality wire bonding connections and greatly improving product yields. it can.

(First embodiment)
Embodiments of a bonding head mounted on a wire bonding apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the bonding head in the first embodiment. FIG. 2 is a side view of the bonding head in the first embodiment. FIG. 3 is a side view of the bonding head showing the internal structure at portion A in FIG.

As shown in FIG. 1, the bonding head 10 according to the present embodiment is fixed to a support arm 40 that is tiltably attached to a support body 50, and a horn 30 that swings up and down by tilting the support arm 40, and a support arm A bonding wire (not shown) is bonded to the bonding surface of the workpiece W by the bonding tool 20 fixed to the tip of the horn 30 at a position protruding from 40. The driving force for tilting the support arm 40 is given by the driving means 60 attached to the support arm 40 via the support 50 and the leaf spring 70. The support body 50 is disposed in a state where the holding rod 101 is clamped. The support body 50 can move up and down along the axis of the holding rod 101, and the support body 50 can be fixed at a predetermined height position in advance.
The workpiece W is set at a position directly below the bonding tool 20 and is provided in a state where it can be moved as necessary. The detailed state of the workpiece W will be described later.

The bonding wire in this embodiment uses an aluminum wire having a diameter of 500 μm. The bonding wire is inserted into an insertion hole (not shown) of the bonding tool 20 so as to be supplied to a bonding surface (not shown) formed on the workpiece W in accordance with the operation of the bonding tool 20. The bonding wire can be disposed in the wire bonding apparatus while being wound around a bobbin (not shown), for example.
In the present embodiment, a bonding tool 20 for wedge bonding formed of a so-called super hard material such as tungsten carbide is used.

The horn 30 to which the bonding tool 20 is attached at the tip is formed into an ultrasonic horn in which an ultrasonic oscillator made of a piezoelectric element is disposed at the base (support arm 40 side). The ultrasonic oscillator in this embodiment uses a piezoelectric element with an output of 50 W that oscillates at 63.7 KHz.
The horn 30 is attached in a state where the base side is fixed to the support arm 40 by a fixture 32. Therefore, the horn 30 tilts with the support arm 40 in the vertical direction, and holds the bonding tool 20 so as to be swingable in the vertical direction (the direction of arrow Z in FIG. 1).

  The support arm 40 has a base 42 connected to the support 50 via a bearing 52. The support arm 40 can tilt (swing) in the vertical direction with the bearing 52 as a support axis (center axis). A leaf spring 70 is attached to the support arm 40. The leaf spring 70 is deformed in accordance with the pressure applied from the bonding tool 20 applied to the bonding surface. As shown in FIGS. 2 and 3, the leaf spring 70 in this embodiment is a thin stainless steel plate formed in a substantially L shape having a short side 72 and a long side 74. The leaf spring 70 is attached to the support arm 40 in a so-called cantilever state in which the short side 72 is attached to the upper surface side of the support arm 40 and the long side 74 is a free end extending in the vertical direction.

As shown in FIG. 2, the support body 50 includes two arm plates 54 extending from the support body 50 toward the support arm 40, and a holding plate 56 that connects the tips of the arm plates 54. Has been. A driving means 60 such as an electromagnetic solenoid serving as a power source for tilting the support arm 40 via the leaf spring 70 is attached between the holding plate 56 and the long side 74 of the leaf spring 70.
In FIG. 3, when the driving means 60 is operated in the arrow Y direction, the support arm 40 tilts downward with the bearing 52 as the central axis. When the support arm 40 tilts downward, the bonding tool 20 attached to the tip of the horn 30 fixed to the support arm 40 comes into contact with the bonding surface. If the driving means 60 is continuously operated even after the bonding tool 20 comes into contact with the bonding surface, the tilting amount of the support arm 40 is restricted because the bonding tool 20 is in contact with the bonding surface. That is, the long side 74 of the leaf spring 70 is curved (displaced) in the direction of the arrow Y as shown in FIG.

  A position detector 80 for detecting the amount of displacement in the arrow Y direction by the driving force of the driving means 60 is attached to the free end of the long side 74 of the leaf spring 70. Position detection means 82 for detecting the position detection body 80 is disposed in a portion of the support 50 that faces the position detection body 80. In the present embodiment, as the position detector 80 and the position detector 82, a magnetic metal formed on a screw and a proximity distance measuring instrument are used.

The position detection unit 82 is connected to a control unit 90 that functions as a pressurizing force calculation unit and a driving force control unit. The controller 90 calculates the pressure applied from the bonding tool 20 applied to the bonding surface based on the amount of displacement at the end 74 of the long side of the leaf spring 70 by the driving means 60 detected by the position detecting means 82. To do.
The relationship between the amount of displacement at the end of the long side 74 of the leaf spring 70 and the pressure of the bonding wire applied to the bonding surface by the bonding tool 20 can be calculated by a prior experiment. The relationship between the displacement amount at the end 74 of the long side of the leaf spring 70 and the pressure of the bonding wire applied to the bonding surface of the bonding tool 20 is stored in advance in a storage unit (not shown) of the control unit 90 that functions as a pressure calculation unit. ing.

  In addition, the storage unit of the control unit 90 stores in advance a design value (design pressure) of the pressure applied to the bonding surface by the bonding tool 20. When the current applied pressure calculated from the displacement amount of the leaf spring 70 is smaller than the designed applied pressure stored in the storage means of the control unit 90, the amount of power supplied to the drive means 60 is increased and the drive force is increased. Perform incremental processing. Subsequently, the control unit 90 calculates the applied pressure again based on the amount of displacement of the leaf spring 70, and repeatedly executes the calculated applied force until the design applied pressure stored in the storage unit of the control unit 90 is reached.

When the applied pressure calculated based on the displacement amount of the leaf spring 70 reaches a preset applied pressure, the control unit 90 activates the ultrasonic oscillator of the horn 30 to oscillate the ultrasonic wave for a predetermined time. . At the same time, the control unit 90 executes control to keep the amount of power supplied to the driving means 60 constant in order to maintain the applied pressure at that time.
When the application of the ultrasonic vibration by the ultrasonic oscillator of the horn 30 is completed, the control unit 90 stops the power supply to the driving unit 60 and releases the applied pressure applied from the bonding tool 20 to the bonding surface. Bonding is complete.

  Such a control unit 90 can be realized by a control program that is stored in a storage unit of a general personal computer separate from the wire bonding apparatus 100 and is operably incorporated on the personal computer.

FIG. 5 is a schematic perspective view showing the overall configuration of the wire bonding apparatus in the present embodiment. The bonding head 10 described above is attached to a holding table 103 having a holding rod 101. The work W to be connected by wire bonding is held on the work holding base 105. The work holding table 105 is mounted on an XY table 107 that can move in the XY direction (so-called plane direction).
The operator manually operates the XY table 107 so that the bonding surface position of the workpiece W is below the bonding tool 20 while confirming the position of the workpiece W on the workpiece holding table 105 by the scope 99. Set with the position set. Such a configuration is particularly preferably employed in the wire bonding apparatus 100 for a prototype.

  The bonding head 10 and the wire bonding apparatus 100 provided with the same in the present embodiment have the above-described configuration. Next, a wire bonding method using the wire bonding apparatus 100 in the present embodiment will be described. The work W in the present embodiment is assumed to have a power transistor mounted on a wiring board.

  The operator confirms the electrode position formed on the power transistor of the workpiece W by the scope 99 and operates the XY table 107 so that the electrode position is positioned below the bonding tool 20. When the workpiece W is positioned, the controller 90 activated manually or automatically supplies power to the driving means 60 and drives it in the direction of arrow Y in FIG. Then, the support arm 40 tilts downward with the bearing 52 as the central axis.

  When the support arm 40 tilts downward, the bonding tool 20 attached to the tip of the support arm 40 comes into contact with the bonding surface. When the driving means 60 is continuously driven, the end of the long side 74 of the leaf spring 70 is bent in the direction of the arrow Y as shown in FIG. 3, and the leaf spring 70 in the state shown in FIG. 3 is shown in FIG. It transforms into a state. In this state, the separation distance between the position detection body 80 attached to the distal end portion of the long side 74 of the leaf spring 70 and the position detection means 82 disposed on the support body 50 changes, and the position detection means 82 is moved to the plate. The amount of displacement at the end of the long side 74 of the spring 70 is detected. That is, the contact state of the bonding tool 20 to the bonding surface can be detected when the displacement amount at the end portion of the long side 74 of the leaf spring 70 is first detected after the driving means 60 is driven. .

  When it is detected that the bonding tool 20 has come into contact with the bonding surface, the control unit 90 stores in the storage unit in advance based on the displacement amount at the end 74 of the long side of the leaf spring 70 detected by the position detection unit 82. With reference to the correspondence data between the displacement amount and the applied pressure, the bonding tool 20 calculates the applied pressure of the bonding wire to the electrode of the power transistor. The control unit 90 compares the applied pressure calculated from the correspondence data between the displacement amount and the applied pressure with the design applied pressure (predetermined applied pressure) stored in the storage unit in advance. Based on the comparison result, the control unit 90 performs a process of increasing the amount of power supplied to the driving unit 60 when the calculated applied pressure is smaller than the design applied pressure. Then, the measurement of the amount of displacement at the end 74 of the long side of the leaf spring 70 by the position detector 82 and the calculation of the applied pressure based on the amount of displacement at the end 74 of the long side 74 of the leaf spring 70 are repeatedly executed. Then, the pressure applied by the bonding tool 20 is made to reach the design pressure.

When the pressure applied to the bonding surface by the bonding tool 20 reaches the design pressure, the control unit 90 keeps the amount of power supplied to the driving means 60 constant. At the same time, the control unit 90 operates the ultrasonic oscillator of the horn 30 to bond the bonding wire and the bonding surface while applying ultrasonic waves to the bonding tool 20 for a required time.
The operating time of the ultrasonic oscillator is stored in advance in the storage means of the control unit 90, and when the preset time elapses, application of ultrasonic vibration by the ultrasonic oscillator stops. Simultaneously with the stop of the ultrasonic oscillation operation by the ultrasonic oscillator, the control unit 90 stops the power supply to the driving means 60, moves the bonding tool 20 away from the bonding surface, and completes the first bonding.

  When the first bonding is completed, the operator operates the XY table 107 while looking through the scope 99 to find the bonding surface of the wiring board at the second bonding position, and operates the XY table 107 to bond the wiring board. The surface position is moved to a position immediately below the standby position of the bonding tool. Thereafter, the control unit 90 is started manually or automatically, and the control unit 90 operates the driving means 60 to bring the bonding tool 20 close to the bonding pad of the wiring board.

  Also on the bonding surface of the wiring board, the bonding wires are ultrasonically bonded in the same manner as the power transistor electrode (first bonding position). When the bonding of the bonding wires on the bonding surface of the wiring board (second bonding) is completed, the control unit 90 oscillates a higher frequency ultrasonic wave from the ultrasonic oscillator of the horn 30 (or manually by the operator). The bonding wire is cut from the bonding surface, and the bonding tool 20 is separated from the bonding surface of the wiring board.

  Since the wire bonding apparatus 100 in this embodiment is frequently used when manufacturing a prototype, wire bonding is performed after the operator confirms the position of the first bonding position and the second bonding position while looking through the scope 99. Therefore, when the first bonding and the second bonding are completed, the bonding tool 20 returns to the initial position (standby position). By repeatedly executing the above, wire bonding connection can be made to all parts in the work W that require wire bonding connection.

  The molded product connected by wire bonding in this way prevents a change in the pressure applied to the bonding surface when the bonding wire is crushed when wire bonding connection using a large-diameter bonding wire is performed. It is possible to maintain the pressing force of the bonding wire to a predetermined pressing force (design pressing force). In other words, problems such as bonding wire breakage due to excessive bonding wire pressure on the bonding surface and insufficient bonding between the bonding surface and bonding wire due to excessive bonding wire pressure on the bonding surface are avoided. This enables high-quality wire bonding connection and improves the product yield.

(Second Embodiment)
FIG. 6 is a perspective view of the bonding head in the second embodiment. FIG. 7 is a side view of a part of the bonding head according to the second embodiment seen through.
The components of the bonding head 10 in this embodiment are the same as the components of the bonding head 10 in the previous embodiment, but are supported by an arrangement in which the long side 74 of the leaf spring 70 extends in the horizontal direction. In addition to being fixed to the arm 40, the present embodiment is different from the previous embodiment in that it further includes contact state detecting means 55 for detecting a state in which the bonding tool 20 is in contact with the bonding surface.

In the wire bonding apparatus according to the present embodiment, as shown in FIG. 6, a horn 30 having a bonding tool 20 attached to one end side is fixed to a holding arm 40 by a fixture 32, and the holding arm 40 is attached to a support body 50. It is the same as that of the previous embodiment in that it is connected to the bearing 52 so as to be tiltable.
A short side 72 of a leaf spring 70 formed in an L shape from stainless steel is attached to the base 42 of the holding arm 40. The long side 74 of the leaf spring 70 extends in the horizontal direction in parallel with the horizontal portion 46 of the holding arm 40.

A driving means 60 that pressurizes the bonding tool 20 to the bonding surface by deforming the leaf spring 70 downward and tilting the holding arm 40 is connected to a middle portion of the long side 74 of the leaf spring 70. The long side 74 of the leaf spring 70 extending in the horizontal direction is displaced to the lower side (arrow C side) of the drawing.
As the driving means 60, an electromagnetic solenoid is preferably used as in the previous embodiment. The drive means 60 in the present embodiment is fixed to a holding plate 56 that connects the upper surface portions of the arm plate 54 extending from the support 50 to the side where the horizontal portion 46 extends from both sides of the horizontal portion 46 of the support arm 40. The output shaft 62 is provided so as to extend and contract in the vertical direction.

  As shown in FIG. 7, a spring holder 64 is attached to the output shaft 62 of the driving means 60, and a coil spring 76 is interposed between the spring holder 64 and the lower surface of the leaf spring 70. A bolt 78 is inserted into the coil spring 76 in the axial direction of the coil spring 76, and one end of the bolt 78 is connected to the spring holder 64 and the other end is connected to the long side 74 of the leaf spring 70. The bolt 78 is disposed in a state of entering into a through hole 48 formed in the horizontal portion 46 of the support arm 40.

  A nut 66 is used as a connecting means between the bolt 78 and the long side 74 of the leaf spring 70. By adjusting the fastening state between the nut 66 and the bolt 78, the protruding height position of the output shaft 62 of the driving means 60 is adjusted. Specifically, when the nut 66 is tightened, the amount of the bolt 78 protruding from the upper portion of the nut 66 is increased, the coil spring 76 is compressed, and the output shaft 62 is protruded (drawn) from the driving means 60. Become. On the other hand, when the nut 66 is loosened, the protruding amount of the output shaft 62 from the driving means 60 is reduced. The tightening state of the nut 66 is adjusted within the upper and lower limits of the protruding amount of the output shaft of the driving means 60.

  By supporting the lower surface side of the long side 74 of the leaf spring 70 with the coil spring 76, when the long side 74 of the leaf spring 70 is displaced by the driving means 60, the long side 74 of the leaf spring 70 and the bolt 78. This prevents the connecting portion from constraining the deformation mode on the free end side of the long side 74 of the leaf spring 70. Since the long side 74 of the leaf spring 70 can be appropriately displaced according to the output of the driving means 60, the position detector 80 can also be appropriately displaced.

  A bracket 81 that houses a position detector 80 for detecting the amount of displacement of the leaf spring 70 is attached to the end of the leaf spring 70 on the long side 74. On the lower surface of the horizontal portion 46 of the support arm 40, position detection means 82 for detecting a change in the position of the position detection body 80 is disposed in a state of being held by a holder 84. The holder 84 is formed in a substantially L shape, and one side is fixed to a position close to the tip of the long side 74 of the leaf spring 70 on the lower surface of the horizontal part 46 of the support arm 40. The position detector 82 is attached to the tip (lower end) on the other side of the holder 84. In the present embodiment, magnets and Hall elements are used for the position detector 80 and the position detector 82.

  As shown in FIG. 7, a leg plate 49 extending downward in the vertical direction is attached to the base portion 42 of the support arm 40 of the present embodiment. The leg plate 49 rotates in the same direction as the tilt direction of the support arm 40 as the support arm 40 tilts around the bearing bearing 52. The support body 50 is provided with a stopper S that restricts the rotation range of the leg plate 49. The stopper S is formed such that the upper end position when the support arm 40 tilts upward from the horizontal state and the lower end position when the support arm 40 tilts can be independently adjusted.

  In the present embodiment, a protruding piece 49A that is attached to the leg plate 49 and protrudes from the surface of the arm plate 54 through a through hole 54A that penetrates the arm plate 54 in the plate thickness direction, and a direction in which the leg plate 49 tilts. A stopper S is constituted by two screws N provided in an arrangement that sandwiches the protruding piece 49A from both sides and a screw holder H. By adjusting the protruding amount of each screw N with respect to the screw holder H, the upper end restriction position and the lower end restriction position of the support arm 40 are set. When the protruding piece 49A comes into contact with the tip of one of the screws N as the support arm 40 and the leg plate 49 are tilted, the movement of the protruding piece 49A is restricted, and accordingly, the tilting of the leg plate 49 and the supporting arm 40 is also restricted. Will be.

  In the lower part of the support 50, one end of the balance spring 53 is locked to the leg plate 49, and the other end is locked to the tip of an adjuster screw 51 attached to the reaction force plate 58 on the side surface of the support 50. The biasing force by the balance spring 53 can be adjusted by the adjuster screw 51. The leg plate 49 can be pulled in the direction of the arrow D by the urging force of the balance spring 53. The weight of the support arm 40 on which the bonding tool 20 and the horn 30 are mounted and the driving means 60 causes the indicating arm 40 to move around the bearing bearing 52. To prevent tilting.

Further, the support 50 is provided with contact state detection means 55 for directly detecting the state in which the bonding tool 20 is in contact with the bonding surface from the tilted state of the support arm 40. As the contact state detection means 55 in the present embodiment, a photoelectric element such as a photomicro is preferably used. Since the leg plate 49 is formed integrally with the support arm 40, if the form of detecting the contact state of the bonding tool 20 to the bonding surface by detecting the position of the leg plate 49 is compared with the previous embodiment. Therefore, it is possible to detect the contact state of the bonding tool 20 to the bonding surface with higher accuracy.
Since the contact state detection means 55 is formed integrally with a slider that is reciprocally inserted from the surface of the support 50 to the inside thereof, the detection position of the leg plate 49 (the bonding tool 20 is bonded to the bonding surface) by adjusting the slider position. Can be set as appropriate according to the actual state.

  Next, a wire bonding method by the wire bonding apparatus 100 using the bonding head 10 in this embodiment will be described. FIG. 8 is a perspective view showing the overall configuration of the wire bonding apparatus in the second embodiment. FIG. 9 is an enlarged view showing a state before and after deformation of the leaf spring in the second embodiment. Since the basic wire bonding method using the bonding head 10 according to the present invention has already been described in the previous embodiment, only the characteristic portions of the present embodiment will be described here.

Before the workpiece W is set, the support arm 40 is displaced slightly upward than the horizontal state. After the workpiece W is positioned and set, the height of the support 50 and the adjuster screw 51 are adjusted to adjust the state of the support arm 40, and the bonding tool 20 is bonded as shown in FIG. The basic state is a state in which no pressure is applied to the bonding surface while being in contact with the surface.
After setting the basic state, the control unit 90 is activated manually or automatically. When the driving unit 60 is operated by the control unit 90, the support arm 40 tilts downward with the bearing belling 52 as the central axis. As the support arm 40 is tilted downward, the leg plate 49 is also tilted to approach the contact state detection means 55. When the contact state detection means 55 detects the leg plate 49, the control unit 90 determines that the bonding tool 20 is in contact with the bonding surface.

  When the contact state detection means 55 detects the leg plate 49, the control unit 90 increases the power supplied to the drive means 60 and applies pressure to the bonding surface by the bonding tool 20, and the leaf spring 70 is shown in FIG. 9B. At the same time, the position detector 82 is caused to detect the position of the position detector 80. Based on the position of the position detector 80 detected by the position detector 82, the controller 90 controls the pressure applied to the bonding surface by the bonding tool 20 in the same manner as in the previous embodiment to complete the first bonding. It goes without saying that the second bonding can also be processed in the same manner as the previous embodiment and the first bonding described above.

  In the present embodiment, the contact state of the bonding tool 20 to the bonding surface is determined by detecting the leg plate 49 that directly reflects the tilting state of the support arm 40, so that the bonding tool 20 contacts the bonding surface. This is advantageous because the state can be detected very precisely.

Although the present invention has been described in detail above based on the embodiments, the embodiment of the present invention is not limited to the contents described above, and other embodiments within the scope not changing the gist of the invention. Needless to say, it belongs to the technical scope of the invention.
For example, in the above embodiment, an electromagnetic solenoid is used as the driving means 60, but other driving means such as a servo motor can be adopted instead of the electromagnetic solenoid. Further, as the position detection means 82, a sensor other than the proximity distance measuring device and the Hall element can be used, and the position detection body 80 can be appropriately changed according to the position detection means 82.

In the first embodiment, the state in which the pressure applied to the bonding surface by the bonding tool 20 has reached the design pressure is detected based on the amount of displacement of the leaf spring 70, but is the same as in the second embodiment. In addition, it is of course possible to dispose contact state detection means 55 for directly detecting the contact state of the bonding tool 20 to the bonding surface from the tilted state of the support arm 40 on the support body 50.
In addition, by attaching the balance spring 53 and the adjuster screw 51 to the first embodiment, it is of course possible to add a function for preventing the support arm 40 from being tilted by its own weight.

  Moreover, in the above embodiment, although the form using the leaf | plate spring 70 which formed stainless steel in the L shape was demonstrated, a driving force is calculated from the displacement by the driving force provided by the drive means 60. FIG. If it can be done, the material of the present invention is not limited to stainless steel, and even if it is not L-shaped but a simple flat plate shape, it is possible to constitute the present invention.

It is a perspective view of the bonding head in a 1st embodiment. It is a bonding head side view in a 1st embodiment. FIG. 3 is a side view of a bonding head showing an internal structure at a portion A in FIG. 2. It is an enlarged view which shows the state which curved the leaf | plate spring of the bonding head. It is a schematic perspective view which shows the whole structure of the wire bonding apparatus in 1st Embodiment. It is a perspective view of the bonding head in 2nd Embodiment. It is the side view which saw through a part of bonding head in a 2nd embodiment. It is a perspective view which shows the whole structure of the wire bonding apparatus in 2nd Embodiment. It is an enlarged view which shows the state before and after a deformation | transformation of the leaf | plate spring in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bonding head 20 Bonding tool 30 Horn 32 Attachment tool 40 Holding arm 42 Base part 46 Horizontal part 48 Through-hole 49 Leg plate 49A Projection piece 50 Support body 51 Adjuster screw 52 Bearing bearing 53 Balance spring 54 Arm board 55 Contact state detection means 56 Holding Plate 58 Reaction force plate 60 Drive means 62 Output shaft 64 Spring holder 66 Nut 70 Leaf spring 72 Short side 74 Long side 76 Coil spring 78 Bolt 80 Position detector 81 Bracket 82 Position detector 84 Holder 90 Control part 99 Scope DESCRIPTION OF SYMBOLS 100 Wire bonding apparatus 101 Holding rod 103 Holding stand 105 Work holding stand 107 XY table

Claims (5)

A bonding tool to connect the bonding wire to the workpiece;
An ultrasonic horn for holding the bonding tool at the tip;
A support arm to which the ultrasonic horn is attached;
A support body rotatably connected to a base portion of the support arm;
Driving means fixed to the support, tilting the support arm with a connecting portion with the support as a support shaft, and pressurizing the bonding tool to the workpiece;
A leaf spring that has one end attached to the support arm as a fixed end, the other end is connected to the drive means as a free end, and is displaced according to the drive force by the drive means;
Position detecting means for detecting a position of a position detecting body attached to the support arm and attached to a free end side of the leaf spring;
Based on the position information of the position detection body detected by the position detection means, a pressure calculation means for calculating the pressure with which the bonding tool presses the bonding surface;
Driving force control means for controlling the driving force of the driving means based on the pressing force calculated by the pressing force calculation means,
The driving force control means is configured such that, after the bonding tool comes into contact with the bonding surface, the bonding tool is in a period from when the pressure applied to the bonding surface by the bonding tool reaches a predetermined pressure until the wire bonding is completed. The wire bonding apparatus is characterized in that the driving force of the driving means is controlled so as to maintain the applied pressure at the predetermined applied pressure.   The wire bonding apparatus according to claim 1, wherein the support is provided with contact state detection means for detecting a state in which the bonding tool is in contact with the bonding surface.   The wire bonding apparatus according to claim 2, wherein the contact state detection unit can adjust a detection position of the contact state.   The wire bonding apparatus according to claim 1, wherein the support is provided with a stopper for restricting a tilting range of the support arm.   The wire bonding apparatus according to claim 1, wherein the bonding wire has a diameter of 100 to 500 μm.

Images