JP2017098281A - Wire bonding method - Google Patents

Abstract

An object of the present invention is to suppress bonding failure caused by floating of a lead terminal. A method of wire bonding an element 11 and a lead terminal 12, wherein a shim plate 23 protrudes from a side surface side of a bonding apparatus 14 having a bonding head 22. A step of bonding to the element 11, a clamper 13 for clamping the lead terminal 12, a step of inserting a shim plate 23 between the lead terminals 12, and the clamper 13 lead through the shim plate 23. The method includes a step of fixing the lead terminal 12 by clamping the terminal 12 and a step of bonding the lead head 12 to which the bonding head 22 is fixed by the clamper 13. [Selection] Figure 1

Description

  The present invention relates to a wire bonding method for a semiconductor element and a lead terminal.

  Conventionally, as a technique in such a field, there is JP-A-08-236571. This publication discloses a method in which a lead frame is fixed by a window clamper in order to prevent a lead terminal from floating when wire bonding between a semiconductor element and a lead frame electrode is performed. Here, the window clamper has a shape in which a window is opened in a plate-like component, and clamps lead terminals adjacent to four sides of the element at a time.

Japanese Patent Laid-Open No. 08-236571

However, when handling a semiconductor device having a large amount of current, such as a power element, a semiconductor device having a large lead terminal is often used. Therefore, in the method of fixing the lead terminal with the above-described conventional window clamper, there is a possibility that the fixing force is insufficient and the lead terminal is lifted. For this reason, the lead terminals are not horizontal, and there is a possibility that bonding failure may occur.
Therefore, the present invention provides a wire bonding method that suppresses bonding failure caused by floating of the lead terminal.

A wire bonding method according to the present invention is a method of wire bonding an element and a lead terminal, and a shim plate is provided on a side surface side of a bonding apparatus having a bonding head, and the bonding head includes: Bonding to the element; a clamper for clamping the lead terminal; a step of inserting one end of the shim plate between the lead terminals; and the clamper via the shim plate And clamping the lead terminal, and the bonding head performs bonding to the lead terminal fixed by the clamper.
Thereby, the bonding apparatus can bond to the horizontal lead terminals.

  As a result, it is possible to suppress the bonding failure caused by the floating of the lead terminal.

1 is a diagram illustrating a configuration of a wire bonding system according to a first embodiment. FIG. 6 is a side view showing a procedure of wire bonding according to the first embodiment. FIG. 6 is a diagram illustrating a state in the middle of the wire bonding operation according to the first exemplary embodiment; It is a figure which shows the structure of the wire bonding system concerning Embodiment 2. FIG. FIG. 9 is a side view showing a procedure of wire bonding according to the second embodiment. FIG. 10 is a diagram showing a state in the middle of wire bonding operation according to the second exemplary embodiment;

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the wire bonding system 1 includes an element 11 formed in a square plate shape, a plurality of lead terminals 12 arranged side by side in the direction of four sides of the element 11, and ends of the lead terminals 12. A clamping claw 13 and a bonding device 14 are provided on the part. In FIG. 1, description of three sides of the lead terminals 12 arranged in the direction of the four sides of the element 11 is omitted, and a state in which the lead terminals 12 are arranged on one side of the element 11 is shown.

  The element 11 is a semiconductor element formed thin in the vertical direction (Z direction). The element 11 changes the alternating current and direct current of the current, drives the motor by performing voltage drop, etc., charges the battery, operates the microcomputer, operates the LSI, controls the power supply, and supplies power. Perform actions such as

  The tips of the plurality of lead terminals 12 are arranged side by side so that each of the four sides of the element 11 faces the side of the element 11. One end of the element 11 and the lead terminal 12 is brought into a conductive state by bonding them with wires. The leading end of the lead terminal 12 has a leading end portion 12a where bonding is performed and a pressing portion 12b pressed against the clamp claws inside the leading end portion 12a (see FIGS. 3A to 3C). Note that the other end of the lead terminal 12 (not shown) is connected to other electronic components.

  The clamp claw (clamper) 13 is a plate that is disposed above the lead terminal 12 and extends in the width direction of the lead terminal 12. An end portion of a shim plate 23 to be described later is inserted between the clamp claw 13 and the lead terminal 12, and the clamp claw 13 descends and presses the pressing portion 12 b of the lead terminal 12, thereby fixing the lead terminal 12.

  The bonding apparatus 14 includes a base 21, a bonding head 22 provided so as to extend vertically and penetrate the base 21, and a shim plate 23 provided on a side surface of the base 21.

  The base 21 is connected to an operating unit (not shown), and moves in the XY direction by the operating unit to change the position of the bonding head 22.

  The bonding head 22 is provided so as to penetrate vertically in the vicinity of the tip of the base portion 21. The position of the tip provided below the bonding head 22 is adjusted by the movement of the base 21. A wire 31 is loaded in the bonding head 22 so as to penetrate vertically. At the tip of the bonding head 22, the wire 31 is bonded to the element 11 using heat, ultrasonic waves, and pressure. In the bonding head 22, the first bond of the wire 31 is performed on the electrode portion of the element 11, and then the 2nd bond is performed on the tip portion of the lead terminal 12.

  The shim plate 23 is a thin plate-like member having elasticity that is provided on the side surface of the base portion 21 of the bonding apparatus 14. The width of the shim plate 23 is substantially the same as the width of the lead terminal 12. For example, the shim plate 23 is formed in a substantially Z shape, and can be expanded and contracted in the horizontal direction and the vertical direction by elasticity. Although FIG. 1 shows a state in which the shim plate 23 is provided only on one side surface of the base portion 21, this structure may be used for all the four side surfaces.

  Next, a procedure for performing wire bonding by fixing the lead terminal 12 with the clamp claws 13 sandwiching the shim plate 23 will be described with reference to FIGS.

  First, the tip of the bonding head 22 is pressed against the element 11, and the 1st bond of the wire 31 is performed (S11). As a result, one end of the wire 31 is bonded to the element 11. Thereafter, the bonding head 22 moves up and leaves the element 11.

  Next, the bonding apparatus 14 moves so as to approach the lead terminal 12 (S12).

  As shown in FIG. 3A, the clamp claw 13 is slightly separated from the lead terminal 12 so that the tip of the shim plate 23 can be inserted between the clamp claw 13 and the lead terminal 12 (S13). At this time, in the lead terminal 12, the tip portion 12a is slightly lowered as compared with the pressed portion 12b. The lead terminal 12 is adsorbed on the plate on which the element 11 and the lead terminal 12 are placed by a vacuum pump, and the position does not move.

  The bonding apparatus 14 further moves so as to approach the lead terminal 12 (S14). At this time, by adjusting the height of the bonding device 14, the tip of the shim plate 23 is placed between the lead terminal 12 to be bonded and the clamp claw 13 as shown in FIG. Inserted.

  As shown in FIG. 3C, the clamp pawl 13 presses the lead terminal 12 from above with the tip of the shim plate 23 sandwiched therebetween (S15). In other words, the clamp claw 13 clamps and fixes the lead terminal 12 with the shim plate 23 interposed therebetween. Here, since the shim plate 23 is sandwiched only between the clamp claw 13 and the lead terminal 12 to be bonded, the pressure of the clamp claw 13 is concentrated on one lead terminal 12. Therefore, even if the lead terminal 12 is thick, it can be pushed down with sufficient force to make the tip horizontal.

  The bonding apparatus 14 further moves so as to approach the lead terminal 12, and the bonding head 22 is disposed on the lead terminal 12 (S16). At this time, the shim plate 23 is contracted in the horizontal direction. Thereafter, by moving the bonding device 14 downward, the tip of the bonding head 22 comes into contact with the lead terminal 12 to perform 2nd bonding. As a result, the other end of the wire 31 is bonded to the lead terminal 12.

  Thus, by sandwiching the shim plate 23 only between the lead terminal 12 for performing bonding and the clamp claw 13, the pressure of the clamp claw 13 is concentrated only on the lead terminal 12 to be bonded. It can be in a horizontal state. Therefore, the bonding head 22 can perform bonding on the lead terminals 12 that are leveled, and can avoid a bonding failure.

  Although the example in which the lead terminal 12 is provided in the X direction with respect to the element 11 has been described above, wire bonding can be similarly performed for the lead terminal 12 provided in the Y direction.

Embodiment 2
The wire bonding system 2 will be described with reference to FIG. The wire bonding system 2 includes an element 11, a plurality of lead terminals 12 arranged side by side in the direction of the four sides of the element 11, a clamp claw 13 disposed on the end of the lead terminal 12, a bonding apparatus 41, . The bonding apparatus 41 includes a bonding head portion 42 in which a base portion 51 extends in the X direction, an XY operation portion 43 to which one end portion of the base portion 51 of the bonding head portion 42 is connected, and an X direction adjacent to the bonding head portion 42. The shim arm 44 is provided so as to extend, and has one end connected to the XY operation unit 43 and a shim plate 45 connected to one end provided to the other end of the shim arm 44. In addition, about the component which has the same function as the component of the wire bonding system 1 of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The bonding head unit 42 includes a base 51 extending in the X direction and a bonding head 52 provided so as to extend in the Z direction.

  The base 51 is provided so as to extend in the X direction, and one end thereof is connected to the XY operation unit 43. The base 51 is moved in the XY direction by the XY operating unit 43 to change the position of the bonding head 52.

  The bonding head 52 performs wire bonding with the element 11. The position of the tip of the bonding head 52 is adjusted by moving the base 51 in the XY directions. The bonding head 52 performs wire bonding to the element 11 using, for example, heat, ultrasonic waves, pressure, or the like.

  In the XY operation unit 43, one end of the base 51 of the bonding head unit 42 and one end of the shim arm 44 are connected to each other. The XY operation unit 43 is operated in the XY direction of the base 51 and is operated in the XY direction of the shim arm 44. For example, the XY operation unit 43 includes a plurality of motors, actuators, and the like that operate the base 51 and the shim arm 44 by receiving power supply, and a control unit that controls these operations. The operations of the base 51 and the shim arm 44 are interlocked.

  One end of a shim plate 45 is connected to the tip of the shim arm 44. The shim arm 44 changes the position of the shim plate 45 by moving in the XY direction by the XY operating unit 43. For example, the shim arm 44 is disposed above the bonding head portion 42 and is provided so as to extend in the X direction like the base portion 51. The shim arm 44 is formed longer in the X direction than the base 51.

  The shim plate 45 is a substantially Z-shaped thin plate-like member that is provided at the tip of the shim arm 44 and has elasticity. The width of the shim plate 45 is substantially the same as the width of the lead terminal 12. For example, the shim plate 45 is formed in a substantially Z shape, and can expand and contract in the horizontal direction and the vertical direction by elasticity.

  Next, a procedure for performing wire bonding by fixing the lead terminal 12 with the clamp claws 13 sandwiching the shim plate 45 will be described with reference to FIGS.

  First, the tip of the bonding head 52 is pressed against the element 11, and the 1st bond of the wire 31 is performed (S21). As a result, one end of the wire 61 is bonded to the element 11. Thereafter, the bonding head 52 rises and leaves the element 11.

  Next, the bonding head unit 42 is driven by the XY operation unit 43 and moves so as to approach the lead terminal 12 (S22). At this time, since the shim arm 44 operates in synchronization with the bonding head portion 42, the shim plate 45 is also in a state of approaching the lead terminal 12.

  As shown in FIG. 6A, the clamp pawl 13 is slightly separated from the lead terminal 12 so that the tip of the shim plate 45 can be inserted between the clamp pawl 13 and the lead terminal 12 (S23). At this time, since the lead terminal 12 is adsorbed on the plate on which the element 11 and the lead terminal 12 are placed by the vacuum pump, the position does not move.

  The bonding head part 42 and the shim arm 44 move so as to approach the lead terminal 12 further (S24). As shown in FIG. 6B, the shim plate 45 is inserted so as to be sandwiched between the lead terminal 12 and the clamp pawl 13 to be bonded.

  As shown in FIG. 6C, the clamp claw 13 presses the lead terminal 12 from above with the tip of the shim plate 45 sandwiched therebetween (S25). Here, since the shim plate 45 is sandwiched only between the clamp claw 13 and the lead terminal 12 to be bonded, the pressure of the clamp claw 13 is concentrated on one lead terminal 12. Therefore, even if the lead terminal 12 is thick, it can be pushed down with sufficient force to make the tip horizontal.

  Thereafter, the bonding head 52 is disposed on the lead terminal 12 (S26). At this time, the shim plate 45 is contracted in the horizontal direction. Thereafter, the bonding head portion 42 is moved downward, the tip of the bonding head 52 abuts on the lead terminal 12, and 2nd bonding is performed. As a result, the other end of the wire 61 is bonded to the lead terminal 12.

  As a result, the shim plate 45 is sandwiched only between the lead terminal 12 that performs bonding and the clamp pawl 13, thereby concentrating the pressure of the clamp pawl 13 only on the lead terminal 12 to be bonded. It can be in a horizontal state. Therefore, the bonding head 52 can perform bonding on the horizontal lead terminals 12 and avoid bonding failure.

  Further, by providing the shim plate 45 at the tip of the shim arm 44, the clamp pawl 13 and the bonding head portion 42 are not connected. Therefore, when the bonding head 52 performs bonding by ultrasonic vibration, the bonding head portion 42 is not fixed to the clamp claw 13 via the shim plate, unlike the wire bonding system 1 shown in the first embodiment. Therefore, bonding can be performed without hindering vibration.

  Although the example in which the lead terminal 12 is provided in the X direction with respect to the element 11 has been described above, wire bonding can be performed similarly for the lead terminal 12 provided in the Y direction with respect to the element 11.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, in the second embodiment, the operation of the base 51 of the bonding head portion 42 and the operation of the shim arm 44 is described as being interlocked, but may be operated independently. Although the shape of the shim plates 23 and 45 has been described as being substantially Z-shaped, the shape is not limited to this shape, and may be a shape having a large number of bent portions. In the above description, the procedure for bonding the lead terminal 12 after bonding to the element 11 has been described. However, the present invention can also be applied to reverse bonding in which bonding is performed first from the lead terminal 12 and then bonding to the element 11 is performed.

DESCRIPTION OF SYMBOLS 1, 2 Wire bonding system 11 Element 12 Lead terminal 12a Tip location 12b Press location 13 Clamp claw (clamper)
14 Bonding device 21 Base portion 22 Bonding head 23 Shim plate 31 Wire 41 Bonding device 42 Bonding head portion 43 XY operation portion 44 Shim arm 45 Shim plate 51 Base portion 52 Bonding head 61 Wire

Claims (1)

A method of wire bonding an element and a lead terminal,
On the side surface side of the bonding apparatus having the bonding head, a shim plate is provided to protrude,
The bonding head performs bonding to the element;
Inserting one end of the shim plate between a clamper for clamping the lead terminal and the lead terminal;
The clamper clamps the lead terminal via the shim plate to fix the lead terminal;
And a step of bonding the lead terminal fixed by the clamper with the bonding head.

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