JPS61101042A - Bonding device - Google Patents

Abstract

PURPOSE:To make the titled bonding device small in size, to make it light in weight as well as to enhance its reliability by a method wherein the voltage applied to a piezoelectric element is properly controlled using the piezoelectric element as the source of driving force for a bonding arm and the like. CONSTITUTION:A bonding head A placed on an X-Y table 1 has a bonding arm 3, a clamper mechanism and the like. The bonding arm 3 is pivotally supported 5 by a supporting member 2, a capillary 4 is engaged at the tip of the bonding arm 3, and a piezoelectric element 7 is engaged at the other end as the source of driving force. The clamper mechanism is composed of a pair of clamper arms 10 and 11 whereon clampers 13 and 14 are fixed at the tip, and the piezoelectric element 7 is also used as the source of driving force for the arms 10 and 11. The capillary 4 is vertically moved by applying voltage on the piezoelectric element 7, and a wire bonding process is performed by opening and closing the clampers 13 and 14.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to bonding technology, and in particular, a bonding technology that is effective when used in wire bonders to improve bonding speed and reliability of bonded products such as semiconductor devices. It is related to.

[Background technology]

In the manufacture of semiconductor devices, pellet ponders, which fix pellets on which semiconductor elements are formed, to package substrates,
A bonding device such as a wire bonder is required to connect the pellet and the external lead using a thin metal wire. These bonding apparatuses have a bonding head mounted on an XY table movable in plane XY directions, and this head includes a bonding arm and a bonding tool as components.

By the way, the above-mentioned bonding arm, which will be described as a representative example of a wire bonder, has a cam mechanism (for example, JP-A-56-1406
36) or a screw mechanism (for example, as described in Japanese Patent Publication No. 57-58081). For example, in a cam mechanism, a cam is rotated by a motor serving as a driving force source, and an arm is swung up and down according to a cam profile. Further, in the screw mechanism, the screw is rotated by a motor serving as a driving force source, and an arm screwed onto the screw is moved up and down along a spiral.

Of course, in addition to these mechanisms, the bonding head is also not provided with a mechanism for driving the wire clamper, a mechanical structure for the electric torch, and a mechanism for performing other sequence operations.

However, in conventional wire bonders with such a configuration, the bonding head is equipped with relatively large mechanisms and electrical components such as a cam mechanism or screw mechanism and a motor that is the drive source for operating the ILA. As a result, the overall weight increases, making it difficult to move quickly when moving on a plane using the Wire bonding becomes older sister.

On the other hand, in the bonding arm drive structure using the cam mechanism or screw mechanism described above, there is a sliding part (rubbing part) between the cam and the arm or between the screw and the arm, so wear particles are absorbed from this sliding part. is generated and this becomes a dust generator. As a result, these abrasion powders adhere to the element pellets, external leads, and the like to which wire bonding is performed, resulting in short circuits occurring at the wire connection portions, etc., thereby reducing the reliability thereof.

These mismatches occur in wire bonders regardless of the thermocompression bonding method or the ultrasonic bonding method, and similar problems occur in pellet bonders as well.

[Purpose of the invention]

The object of the present invention is to provide a bonding apparatus including a bonding head with v! It is an object of the present invention to provide a bonding device which is capable of reducing the number of sliding parts and reducing the number of cracking parts, thereby increasing the cutting speed and improving the reliability of bonded products.

Another object of the present invention is to provide a bonding apparatus that is lightweight and has a smaller bonding head, and is also smaller as a whole.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief summary of typical inventions disclosed in this application is as follows.

That is, a compact piezoelectric element is used for the driving force of the bonding arm etc. supported on the bonding head, and the voltage applied to the pressure wire is controlled. This eliminates the need for a cam mechanism or screw mechanism and a motor that is the driving force source for the softwara, reducing the weight and reducing the number of sliding parts.
This improves the reliability of bonded products by preventing dust generation.

In addition, by interposing an amplitude enlargement lever between the bonding arm, etc. and the piezoelectric element, the amount of displacement of the piezoelectric element can be increased and transmitted to the bonding arm, etc., and the piezoelectric element can be made smaller to achieve the same stroke operation. It is also possible to reduce the size of parts other than the bonding arm and the rib.

Note that piezoelectric elements can also be used in each driving part of the clamp in the wire bonder and the ball forming torch of the thermocompression bonder.

[Embodiment 1] FIG. 1 is a diagram showing an embodiment in which the present invention is applied to a pole bonding type wire bonder, in which FIG. In the figure, a small-sized pressure and cable is used as a driving force source, and a bonding head A is mounted on an XY table 1 movable in plane X and Y directions. A bonding arm 3 that can swing up and down is provided on a support 2 in the head A. This bonding arm 3
A capillary 4 as a bonding tool (wire connection tool) is attached to the tip (one end) protruding to the left in the figure, and a part from the proximal end (other end) is pivoted to the support 2. There is. A protruding piece 6 is provided on the other end of the arm 3, which is located at the pivot point 5', and a piezoelectric element 7 as a driving force source is engaged with the protruding piece 6. That is, - the support 2
A bracket 8 is fixed so as to cover the upper part of the protruding piece 6, and a pair of piezoelectric elements are attached to the bracket 8 and the support body 2 in a straight line state, respectively. The protruding piece 6 at each inner end of a and 7b
It is designed to hold the upper and lower parts. The piezoelectric element 7a
*7 b is lead zirconate titanate (PZT)
A plurality of elements made of piezoelectric ceramics are stacked in the thickness direction, and by applying a pressure to this piezoelectric element 'Ia, 1bK@, the entire element expands and contracts in the vertical direction in the drawing. Incidentally, PZT is a trademark of Rayvite Co., Ltd., which is derived from the letters P for lead, Z for zircon, and T for titanium. In this example, voltages in opposite directions can be applied to the piezoelectric elements 7 a + 7 b, so that when one element is expanded, the other is shortened. In addition, when the product name [NTK Piezo Stack T10505MM (Nippon Spark Plug Co., Ltd.)] is used as the piezoelectric elements 7 a + 7 b, a displacement of 35 μm is obtained by applying 400 V.
Moreover, the maximum generated force is 70, and 9f cannot be obtained.

Of course, the above-mentioned applied voltage can be changed continuously or stepwise, and the displacement lids of the elements 7a and 7b can be adjusted accordingly. In the figure, it is a spring for biasing one end of the nine bonding arm 3 downward.

On the other hand, a clamper mechanism is provided above the bonding arm 3 and is operated by a drive means different from the drive means for the bonding arm 3. This clamper machine w is capable of being vertically displaced relative to the bonding arm 3, for example, in relation to the movement of the bonding arm 3.

This clamper mechanism includes a pair of clamper arms 10.11.
A clamper 13.14 is fixed to the tip of each arm 10.11 on 1u of the capillary 4. Although not shown, a piezoelectric element is also used as a driving force source for vertically moving the clamper arms 10, 11 to reduce the size and weight. [7] A violet and small-shaped indentation cord (
A driving force source (15) for the clamper mechanism is interposed, and a trap is provided to apply a required voltage to this. The clamper 1
3. Above 14 is a gold wire (bonding wire).
A spool 17 wound with a wire) 16 is arranged to support the dough on the support 2, and the wire 16 is pulled downward from the spool 17 to connect the clamper 13, 14 and the capillary 4.
is inserted. On the other hand, an electric torch 18 for forming a ball (gold pole) 16a at the tip of the wire is disposed below the capillary 4, and is configured to move forward and backward, or is a driving force source for this forward and backward movement. However, in this embodiment, a piezoelectric element (not shown) is used.

In the figure, reference numeral 19 denotes a bonding stage, in which a bonding target body 22 consisting of, for example, a lead frame 20 and an element pellet 21 is mounted, and a wire 16 is connected between a portion of the frame 20 and the element pellet 21.

According to the above configuration, the vertical movement of the capillary 4 due to the vertical swing of the bonding arm 3 and the vertical movement of the clamper arm 10.
Wire bonding is performed on the object to be bonded 22 by the thermocompression method by opening and closing the clampers 13 and 14 by the rotation of the clamper 11, and by the actions of the electric torch 18 and the bonding stage 19. Note that at this time, ultrasonic vibrations are applied to the bonding arm. Note that a mechanism for applying ultrasonic vibration to the bonding arm is not shown. When the bonding arm 2 swings up and down, the voltages applied to the piezoelectric elements 7a and 7b are controlled over time, so that the piezoelectric elements 7a and 7b move toward the protrusion 6, that is, the arm 3, as they expand and contract. By moving the other end up and down integrally, the entire arm 3 is swung up and down. As a result, the lever ratio (the lengths of the capillary 4 and the protruding piece 6 with respect to the pivot point 5, e+, -61 ratio -1
3+ /13 t) by piezoelectric element 7 a + 7
The displacement it of b is magnified and cannot be transmitted to the capillary 4. Note that the stretching of each piezoelectric element 7a, 71) is not necessarily in a one-to-one correspondence, and as shown in FIG.
, 7b, and bonded body 2.
It is possible to deal with variations in height between the two sides. It is also possible to open and close the reclampers 13 and 14 by controlling the voltage applied to the piezoelectric element 15.
"stomach.

Therefore, according to this wire bonder, a cam mechanism or a screw mechanism is used as the driving force source for the mechanical operation of the electric torch 18 in the bonding arm 3 and the clamper arm 10. Since it uses an extremely compact piezoelectric element, the overall weight of the bonding head 2 can be reduced by 1°, and horizontal movement by the XY table 1 can be easily achieved.
Since there are almost no frictional parts, there is no generation of dust such as abrasion powder, and the reliability of the bonded body 22 can be improved.

, Figure 3 shows a modification of the previous example, in which the piezoelectric element 7
In order to further expand the displacement leaf caused by a + 7 b and move the capillary 4 up and down, a lever 23- for increasing the amplitude is interposed. That is, this enlarged lever 23 has one end 23a pivoted to the other end of the bonding arm 3, and the other end 23'b pivoted to the support 2.
The piezoelectric elements 7a+7b are engaged at the closer positions.

According to this embodiment, the lever ratio of the bonding arm 3 is 4.
3 + / -13t Lever ratio of the enlargement lever 23 (length l between the other end 23b and one end 23a)
b and the length 14 to the piezoelectric element 7 -gs/-ga) phase opening e@xis/, e2X-g4 magnification ratio does not decrease and a sufficiently large vertical stroke of the capillary 4 is obtained. I can do it.

[Embodiment 2] FIG. 4 (A+, [3) is a diagram showing a wire bonding apparatus which is another embodiment of the present invention, and in the figure, the same parts as FIGS. 1 and 3 are In this example, as shown in the figure, one clamper arm IOA is pivoted to the support 2 so as to be able to swing up and down. It is pivotally mounted on the IOA so that it can rotate horizontally.

Both clamper arms IOA and IIA have clampers 13 and 14 attached to their tips, respectively, and are configured to be openable and closable by piezoelectric elements 15 interposed at their base ends. A tip 24b of a first enlarged lever 24 whose base end 24a is pivotally supported on the support 2 is connected to the other end of the one clamper arm IOA, and a pin is connected to the other end of the first enlarged lever 24 at a position closer to the base end of the first enlarged lever 24. 25 and the tip 26a of the second enlargement lever 26
is connected to. The second enlarging levers 26 are arranged in parallel and in opposite directions to the first enlarging lever 24, and the base end 26b is pivotally supported on the support 2, and a pair of brackets 8 are used at a position from the base end 26b. Piezoelectric elements 7a + 7b are engaged.

On the other hand, a bonding arm 3A having a capillary 4 fixed to its tip is pivoted 27 near the base end 3Aa to a part of the one clamper arm IOA so as to be able to swing vertically. Then, this base end 3Aa and the clamper arm IOA
A piezoelectric element 28 and a tension spring 29 are interposed between the two.

According to this example, the opening and closing operations of the clampers 13, 14 can be achieved by horizontally rotating the other clamper arm 11A with respect to the one clamper arm IOA using the piezoelectric element 15. In addition, by controlling the expansion and contraction of the piezoelectric elements 7a + 7b, the displacement thereof is expanded by the ratio of the second and first expansion levers, L, and the lever ratio of the clamper arm IOA. Move the clampers 13 and 14 up and down from K. Furthermore, by controlling the expansion and contraction of the piezoelectric element 28,
The bonding arm 3A can be vertically oscillated relative to the clamper arm IOA, and the bonding arm 3A can vertically move the capillary 114 with a large stroke by the sum of the vertical oscillation of the clamper arm IOA and the relative oscillation.

In this embodiment as well, since the cam mechanism or screw mechanism and the motor which is the driving force source of the cam mechanism or the screw mechanism are not used, the 411i
It is possible to reduce the number of sliding friction points and improve the reliability and reliability. In addition, in this embodiment, the first. Second
Since the amplitude is expanded using the expansion levers 24 and 26, the length of each lever 24 and 26 can be shortened in order to make the same stroke (a), and the entire device can be made smaller.

In addition, in this embodiment, the clamper arm and the bonding arm share a common part, and the driving force source for them is also shared, so it is possible to reduce the weight and size of the bonding head A. This has a great effect on reducing the amount of water used.

〔effect〕

il+ A piezoelectric element is used as a driving force source for components such as the clamper and electric torch as well as the bonding arm, and the voltage applied to this piezoelectric element can be controlled, so the piezoelectric element can be expanded and contracted by controlling the applied voltage. Moreover, it is possible to operate the bonding arm, clamper, electric torch, etc. based on this displacement, so the cam mechanism or screw mechanism conventionally used for these and the motor etc. that are the driving force source of the seven screws are no longer required. As a result, it is possible to significantly reduce the weight of the entire device including the bonding head, increase the speed of operation due to the movable table, and reduce vibration by reducing inertia.

(Since the conventional cam mechanism or screw mechanism etc. in the 21 bonding head can be eliminated, the number of sliding friction points can be reduced, and dust generation such as abrasion powder can be significantly prevented, preventing it from adhering to objects to be bonded such as semiconductor devices. This can improve the reliability of bonded objects such as semiconductor devices.

(31 Since a lever is provided between the bonding arm, clamper, etc. and the piezoelectric element as the driving force source to increase the amplitude (displacement it), it is possible to obtain the necessary and sufficient stroke amount by arbitrarily setting the lever ratio. can.

(By configuring the levers that expand the 41 amplitude with several levers, the length of each lever can be shortened, and the bonding head or the entire device can be downsized by kneading.

(5) The piezoelectric element is violet and small in shape.

Therefore, when used as a driving force source for the bonding arm of a bonding device, crankshaft, mechanical operation of an F#1 torch, XY table, etc., compared to a conventional cam mechanism or screw mechanism and a motor as its driving force source. This allows the bonding head to be made much smaller and moreover compact in size.

(6) A piezoelectric element generates force and shape displacement when a voltage is applied to it. Therefore, positional displacement can be performed quickly and with high precision in response to electrical input such as voltage. In addition, since the displacement l corresponding to the electrical input amount of voltage is performed, the control is reliable and the variation t'
You can achieve something of high precision. Therefore, the present invention, which uses a piezoelectric element as a driving force source for the bonding arm of a bonding device, a clamper, an electric torch, an XY table, etc., is more effective than a cam mechanism or screw mechanism and a motor as its driving force source. As a result, the accuracy, certainty, and reliability of controlling the operations of bonding arms, clampers, etc. are much improved.

(7) The present invention, that is, a bonding arm mechanism and a clamper mechanism using a piezoelectric element as a driving force source.

The mechanical operating mechanism of the electric torch, the XY table mechanism, has fewer mechanical elements, fewer mechanical sliding parts, and is wear-free. Therefore, compared to conventional cam mechanisms or screw mechanisms that have many mechanically sliding parts, the present invention has much better power transmission performance because there is no wear, and there is no mutual mechanical contact during power transmission. The accuracy of power transmission between elements is high and does not change or deteriorate over time. In addition, the present invention, which has fewer sliding parts and less wear, can operate in a clean atmosphere because there are fewer dust-generating parts, and there is less foreign matter adhering to the object to be bonded. Adverse effects such as occurrence of defects in the bonded object can be reduced.

Although the invention made by the present inventor has been specifically explained based on examples, the present invention is not limited to the above examples (and may be modified at any time without departing from the gist of the invention). Needless to say, for example, the shape of the bonding arm, the clamper arm, the shape and structure of the amplitude expansion lever, and the correlation structure between these and the piezoelectric element can be completely modified. One of the elements can be alternatively configured with a spring or the like.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to a wire bonder for pole bonding, which is the field of application in which the invention was made, but it is not limited to that field, and for example, it can be used as a wire connection tool. It can be similarly applied to ultrasonic wire bonders using wedges and pellet bonders that perform pellet bonding and have a collet attached to the tip of the bonding arm.

[Brief explanation of drawings]

Figures 1 (4) and (B) are a side view and a plan view showing the wire bonding device on the one-flow side of the present invention, and Figure 2 shows a pair of piezoelectric elements that are the driving force source for moving the capillary up and down. FIG. 3 is a side view showing a wire bonding device according to another embodiment of the present invention, and FIG. 4 (AJ, B) shows a wire bonding device according to another embodiment of the present invention. They are a side view and a plan view.A.°° bonding head, 1...XY table,
2... Support body, 3.3A... Bonding arm,
4 Capillary, 7 (7a, 7b)...Piezoelectric element, 9.
...Spring, 10,1. OA, 11. IIA...
Clamper arm, 13.14... Clamper, 15...
・Piezoelectric element, 16... wire, 17... spool,
18...Torch nozzle, 19...Bonding stage, 22...Bonding object, 23...Enlargement lever, 24...! 1K d beast r kerii- (＼

Claims (1)

[Claims] 1. A bonding apparatus characterized in that a piezoelectric element is used as a driving force source for a bonding arm in a bonding head, and the bonding arm is configured to operate by controlling the voltage applied to the piezoelectric element. . 2. The bonding arm is pivotally supported on a support in the bonding head so as to be able to swing up and down, a bonding tool is attached to one end of the bonding arm, and a piezoelectric element is interposed between the other end and the bonding head. A bonding device according to scope 1. 3. A bonding device according to claim 2, wherein a pair of piezoelectric elements are provided, each outer end being attached to the bonding head side, and each inner end holding the other end of the bonding arm. 4. The bonding apparatus according to any one of claims 1 to 3, which is a wire bonder and uses a piezoelectric element as a driving force source for a clamper included in a bonding head. 5. The bonding apparatus according to any one of claims 1 to 4, which is a wire bonder and uses a piezoelectric element as a driving force source for mechanical operation of an electric torch included in the bonding head. 6. A piezoelectric element is used as a driving force source for the bonding arm in the bonding head, and an amplitude expansion lever is interposed between the piezoelectric element and the arm to expand the amount of displacement of the piezoelectric element and transmit it to the arm. 1. A bonding apparatus characterized in that the bonding arm is configured to operate by controlling the voltage applied to the element. 7. The bonding arm is pivotally supported on a support in the bonding head so as to be able to swing up and down, and a bonding tool is attached to one end of the arm, and an amplitude expansion lever is connected to the other end, which can be swung by a piezoelectric element. A bonding apparatus according to claim 6, which is configured as follows. 8. The bonding apparatus according to claim 6 or 7, wherein a plurality of amplitude enlargement levers are arranged in series to increase the enlargement ratio, or the length of the lever at the same enlargement ratio is reduced. 9. The clamper arm to which the clamper is attached is configured to be vertically swingable by a piezoelectric element, and a bonding arm is supported so as to be swingable relative to the clamper arm, and a piezoelectric element is interposed between these two arms. A bonding apparatus according to claim 6, comprising: