JP3132496B2 - Die bonding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding equipment which allows changes to the setting of bonding load to be made, without replacement of components and moreover which hardly damages electronic components. SOLUTION: A bonding head of this equipment is composed of lifting and lowering rod 21, having a chucking section 22 for chucking an electronic component P at its lower end, a diaphragm DP located above the lifting the lowering rod 21, and a downward movement limiting means for limiting the downward movement of the lifting and lowering road 21. It also has a pressure adjusting means for adjusting the magnitude of the pressure of the compressed air supplied to the diaphragm DP from a source of compressed air. The pressing force of the lifting and lowering rod 21 applied to the electronic component P is adjusted through the pressure of compressed air applied to the lifting and lowering rod 21 through the diaphragm DP.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding apparatus which facilitates setting of a bonding load of an electronic component and prevents the electronic component from being damaged when the suction portion contacts the electronic component.

[0002]

2. Description of the Related Art A die bonding process of a die bonding apparatus for mounting an electronic component (die) on a lead frame is performed as follows. That is, the lead frame is positioned on the transport rail, and a bond is applied to the lead frame by a dispenser or the like. On the other hand, the electronic component cut into a predetermined shape from the wafer is pushed up by the ejector, the bonding head is lowered, the pushed up electronic component is sucked by the suction portion of the bonding head, and picked up by raising the device. . Then, transfer to the lead frame side,
The bonding head is lowered again, the electronic components sucked by the suction section are mounted on a lead frame, and the apparatus is raised. As described above, the bonding head of the die bonding apparatus performs at least two times in one stroke of the die bonding process (when the electronic component pushed up by the ejector is picked up and when the picked up electronic component is mounted on the lead frame). Elevating operation is performed.

FIG. 7 is a view showing an example of a conventional bonding head. In FIG. 7, LF is a lead frame, B is a bond, P is an electronic component, 110 is a support mechanism of a bonding head, 120 is an upper part supported on the support mechanism 110 so as to be able to move up and down, and a lower part is an electronic part. A movable mechanism having a suction section 122 for sucking P is a moving means for moving the support mechanism 110 in the XYZθ directions.

[0004] The movable mechanism 120 includes a suction nozzle 122a, a die collet 122b attached to a lower portion of the nozzle 122a, and a lifting rod 121 connected to an upper portion of the nozzle 122a.

The support mechanism 110 includes a holder 111,
An elevating rod 121 provided in the holder 111
And guide bushes 112 and 113 for supporting the ascending and descending freely.

[0006] K is a bonding load setting spring that is attached at the upper end to the lower part of the holder 111 and at the lower end to the upper part of the nozzle 122a. As described above, in the conventional means, assuming that the pressing force by the moving means 130 moving in the XYZθ directions is constant, the bonding load for the bonding head device to press the electronic component against the lead frame is set only by the spring K. Was something.

[0007]

By the way, in the field of die bonding, large-variety, small-quantity production has been performed, and electronic components of various sizes are bonded.

Here, if the size of the electronic component is large, the contact area becomes large and a large amount of bonding is required. Therefore, it is necessary to apply a large bonding load and firmly bond. Conversely, small electronic components require a small bonding load to prevent damage to the electronic components.
As described above, when the size of the electronic component is different, an appropriate bonding load is different, and thus the setting of the bonding load is often changed.

However, if the bonding load is set only by the spring K as in the conventional means, the spring K must be replaced every time the setting is changed, and it is necessary to prepare various springs K. In addition, at the time of the replacement, it is necessary to stop the entire die bonding process, which causes a problem that the work yield is reduced.

The movable mechanism 120 is supported by the support mechanism 110 by a spring K. Then, as shown in FIG. 8B, when the holder 111 moves down to the lowest position, the following phenomenon may occur.

That is, when the holder 111 descends, an upward inertial force acts on the movable mechanism 120 due to its downward acceleration, and the spring K is in a state of being contracted from its natural length. When the holder 111 reaches the lowermost position and stops, the upward acceleration becomes zero, and the movable mechanism 120
Inertia force does not act on. Therefore, the spring K is released from the contracted state, and vibrates (expands or contracts).

As a result, the suction part 122 located at the lower part of the movable mechanism 120 repeatedly rises (FIG. 3C) and descends (FIG. 3B) (jumping phenomenon) to damage the delicate electronic component P. There was a risk of doing.

In recent years, in order to increase the speed of bonding, the acceleration and the inertial force have been increasing. Therefore, when the spring constant of the spring K is small, the amplitude of the vibration (expansion and contraction) increases, and the jumping phenomenon has become more remarkable.

Therefore, in the conventional means, the spring constant of the spring K is increased to suppress this jumping phenomenon. As described above, when the spring constant is increased, the amplitude is reduced. However, even in this case, the product of the spring constant and the amplitude (the force exerted on the electronic component P by the suction nozzle 122a) cannot be reduced, and the above-described problem that the electronic component P is easily damaged can not be solved. Did not.

FIG. 8 shows a state in which the picked-up electronic component is mounted on the lead frame during the two lifting operations of the bonding head device. When picking up the electronic component pushed up by the ejector, FIG. Have the same problems as described above.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a die bonding apparatus which can change a setting of a bonding load without replacing a part, and is hard to damage an electronic part.

[0017]

According to the present invention, there is provided a die bonding apparatus in which an electronic component is sucked to a suction portion of a bonding head to be picked up and mounted on a substrate. A lifting rod having a diaphragm, a diaphragm disposed above the lifting rod, and a descent limit limiting means for limiting a descent limit of the lifting rod, and the pressure of compressed air supplied to the diaphragm from a compressed air source. Pressure adjusting means for adjusting the size is provided, and the pressing force of the lifting rod applied to the electronic component by the pressure of the compressed air applied to the lifting rod via the diaphragm is adjusted.

According to the above configuration, the external force for pushing down the lifting rod is determined by the magnitude of the pressure of the compressed air applied to the diaphragm. Therefore, when changing the setting of the bonding load, the pressure of the compressed air may be changed, and there is no need to replace any components. In addition, when the suction section is about to descend, the external force that pushes down the elevating rod is reduced, so that an excessive shock is not applied to the electronic component, and damage to the electronic component can be prevented.

[0019]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1A is a perspective view of a die bonding apparatus according to an embodiment of the present invention, and FIG.
2 is a partial exploded view of the bonding head, FIG. 2 is an assembly view of the bonding head, FIG. 3 is a longitudinal sectional view of the bonding head, FIG. 4 is a circuit diagram of control means of the bonding head, and FIG. FIG. 6 is a longitudinal sectional view of the bonding head in the case of FIG.

As shown in FIGS. 1 and 2, this die bonding apparatus includes a moving mechanism 3 for moving the supporting mechanism 10 in the YZθ directions in addition to the supporting mechanism 10 and the movable mechanism 20.
0, a passive element DP provided in the support mechanism 10, and a control means 4 for applying an external force to push the movable mechanism 20 to the support mechanism 10 based on the set value of the passive element DP.
0.

Reference numeral 1 denotes a bonding head, which has a suction portion 22 (which comprises a collet-type nozzle or the like as will be described later) that sucks an electronic component P on the wafer W as an electronic component supply portion. LF is a substrate such as a lead frame on which the electronic component P is mounted (hereinafter simply referred to as a lead frame).

First, the moving means 30 of the support mechanism 10 will be described with reference to FIG.

Reference numeral 311 denotes a first direct motor comprising a linear motor, which has a horizontal guide 312 and a slider 313 which slides on the guide 312. The head 1 is mounted on the slider 313. Move in the horizontal direction Y. 314 is a coil provided on the guide 312, 315 and 316 are a yoke and a magnet provided on the lower surface of the slider 313. Slider 31
3 is provided with an air hole (not shown) constituting an air receiver, and slightly floats on the guide 312 to move in the lateral direction Y.

In FIG. 1B, reference numeral 321 denotes a second direct motor which is a linear motor provided on the bonding head 1. A yoke 322 has a hollow shaft 3 inserted therein, and the support mechanism 10 is connected to a lower portion of the shaft 3. The movable mechanism 20 is supported by the support mechanism 10 so as to be able to move up and down, and a suction part 22 is provided at a lower end of the movable mechanism 20. The yoke 322 has a disk shape, and has a magnet 323 mounted on its peripheral surface.
4 are provided. Therefore, when the coil 324 is energized, the shaft 3 and the support mechanism 10 move up and down in the vertical direction Z, and as the support mechanism 10 moves up and down,
The suction part 22 at 0 and its lower end performs an operation of picking up the electronic component P on the wafer W and an operation of mounting the electronic component P on the lead frame LF.

Reference numeral 331 denotes a third direct motor composed of a linear motor.
3. A coil 334 is provided. A spline 4 is mounted on the shaft 3, and the spline 4 penetrates the center of the magnet 332 so as to be able to move up and down. When the coil 334 is energized, the shaft 3 and the support mechanism 10
Rotates in the θ direction about its axis.

The moving means 30 is constructed as described above, and the operation of the moving means 30 will be described below.

The first direct motor 311 is driven to move the bonding head 1 directly above the wafer W. Next, the second direct motor 321 is driven to move the suction unit 22 up and down to suck and pick up the electronic component P on the wafer W. Next, the first direct motor 311 is driven to move the bonding head 1 directly above the lead frame LF, and the second direct motor 321 is driven to transfer the electronic component P to the lead frame L.
Mount on F. By driving the third direct motor 331 during the above operation, the shaft 3 and the support mechanism 10 are rotated by θ, and the rotation angles of the suction unit 22 and the electronic component P are set.

Here, die bonding is performed in a clean room in order to prevent dust from adhering to the electronic component P. In the conventional means, a timing belt, a ball screw and the like are frequently used for the moving means. . Therefore, in the conventional means, dust is generated due to mechanical friction associated with driving of the timing belt and the like, and metal powder, belt powder, and grease powder are scattered, so that the cleanliness of the clean room is easily reduced.

On the other hand, in this means, since the timing belt, the ball screw, and the like are not used at all, the load on the direct motors 311, 321, and 331 is extremely small. The generation of dust due to friction does not occur, and the cleanliness of the clean room can be prevented from lowering.

That is, the moving means according to the present embodiment
A bonding head, and a first direct motor for reciprocating the bonding head in a lateral direction,
Further, the bonding head includes a second direct motor having a suction portion below and for vertically moving the support mechanism, and a third direct motor for rotating the support mechanism by θ.

Note that this means is used for the electronic components P on the wafer W.
Is transferred to a displacement correction stage, where the displacement of the electronic component P in the XYθ directions is corrected, and then the electronic component P is picked up by the bonding head 1 and mounted on a lead frame LF. Applicable.

Next, with reference to FIG.
A detailed structure such as will be described.

In the support mechanism 10, reference numeral 11 denotes a horn-shaped holder, and a large-diameter concave portion 11a is provided in the upper center of the holder 11, and the concave portion 11a is coaxial with the concave portion 11a. Also, a small-diameter circular hole 11b is continuously provided. Reference numeral 11c denotes an open-to-atmosphere hole communicating with the concave portion 11a, and reference numeral 11d denotes a female screw portion provided vertically. Then, the guide bush 16 is fitted into the circular hole 11b,
An elevating rod 21, which will be described later, is supported by the guide bush 16 so as to be able to move up and down with respect to the holder 11.

Reference numeral 12 denotes a diaphragm case mounted on the holder 11, and a circular hole 12a having a diameter larger than that of a boss 23b of a diaphragm plate 23 (described later) is formed in the center. Reference numeral 12b denotes a circular groove which is recessed on the outer peripheral side of the circular hole 12a of the case 12, and a peripheral thick portion DPa of the diaphragm DP is fitted into the circular groove 12b. Reference numeral 12c denotes a through hole opened at a position corresponding to the female screw portion 11d, and reference numeral 12d denotes a step portion which engages with the upper inner peripheral edge of the concave portion 11a of the holder 11.

Reference numeral 13 denotes a lid-shaped diaphragm case.
The case 13 rests on the case 12. 13a is a boss portion of the case 13, 13b is the same flange portion, and a circular hole 13c is opened in the center of the boss portion 13, and a through hole 13d is opened at a position corresponding to the through hole 12c of the flange portion 13b. Have been. The reduced diameter portion 15a of the pipe 15 is fitted into the circular hole 13c, and the through hole 13d,
The male screw part 14a of the bolt 14 is inserted through the male screw part 12c, and the male screw part 14a
1d. In the present embodiment, the diaphragm case 12 and the case 13 serve as a diaphragm mounting member.

In the movable mechanism 20, reference numeral 22 denotes a suction unit, of which 22a is a suction nozzle, which is connected to a suction system (not shown), and 22b is a die collet attached to a lower portion of the nozzle 22a. Reference numeral 21 denotes an elevating rod connected to the upper portion of the nozzle 22a, and reference numeral 21a denotes a reduced diameter portion of the rod 21.

Reference numeral 23 denotes a diaphragm plate.
a is a circular hole passing through the center of the plate 23, and the reduced diameter portion 21a of the lifting rod 21 is fitted into the circular hole 23a, and the lifting rod 21 and the diamond frame plate 23 are
Be linked. Reference numeral 23b denotes a boss of the plate 23, and the diaphragm DP is in circumferential contact with the boss 23b. 23c is a flange portion of the plate 23;
Since the lower surface of the flange portion 23c is in contact with the bottom surface of the concave portion 11a, the lowering limit of the movable mechanism 20 (diamond frame plate 23, lifting rod 21 and suction portion 22) is limited. The flange portion 23c serves as a descent limit limiting means for limiting the descent limit of the lifting rod 21 with respect to the holder 11.

Further, DP is a diaphragm which is an example of a passive element, and a peripheral thick portion DPa of the diaphragm DP.
Is fitted into the circular groove 12b, and the holder 11 and the diaphragm cases 12, 13 are connected by bolts 14. Then, as shown in FIG. 3, the space between the holder 11 and the diaphragm case 13 is opened to the first space S <b> 1 communicating with the flow path 15 b of the pipe 15 and to the atmosphere by the diaphragm DP in contact with the diaphragm plate 23. Into a second space S2. The output (compressed air) of the control means 40 is provided in the first space S1 by the shaft 3
(FIG. 1B) is supplied via a communicating pipe 15 and this output acts as a pressing force for pressing the diaphragm DP, that is, a bonding load.

Next, the control means 40 will be described in detail with reference to FIG. In FIG. 4, AS is a compressed air source, and V is a vacuum unit such as a vacuum pump.

RH is a high pressure setting regulator connected to the compressed air source AS, and the output pressure is 1 kgf / m ＾ 2
It is constant before and after. RL is a low-pressure setting regulator using a single-acting variable actuator. The low-pressure setting regulator RL is connected to the output of the regulator RH, and controls the output pressure of the high-pressure setting regulator RH.
The pressure can be reduced to a low pressure that is finely divided into about 256 divisions. That is, the regulator is a pressure adjusting means. In FIG. 4, H indicates a high-pressure section and L indicates a low-pressure section.

SV1 is a first three-port electromagnetic switching valve for switching between high pressure and low pressure. The P port of the first switching valve SV1 is connected to the output of the low pressure setting regulator RL, and the R port is connected to the high pressure. Each is connected to the output section of the setting regulator RH. SV2 is the second 3 for switching between negative pressure and positive pressure.
Port solenoid-operated directional control valve.
The port is connected to the vacuum section V, and the R port is connected to the first switching valve SV.
1 of the second switching valve SV2.
The port communicates with the first space S1 located on the upper surface side of the diaphragm DP via the pipe 15.

Then, as shown in FIG. 4A, the first and second
When both of the switching valves SV1 and SV2 are demagnetized, the high pressure is applied to the first space S1 from the output of the high pressure setting regulator RH via the R port and the A port of the first and second switching valves SV1 and SV2. H compressed air is supplied, and the diaphragm DP is pressed downward by a large pressing force. Then, as shown in FIG. 3, the lower surface of the diaphragm plate 23 contacts the bottom surface of the concave portion 11a of the holder 11,
The suction part 22 is provided for the support mechanism 10 such as the holder 11.
It is in the lowest position.

As shown in FIG. 4 (b), when both the first and second switching valves SV1 and SV2 are excited from this state, the vacuum section V causes the P port and the A port of the second switching valve SV2 to be excited. Through the first space S1. Then, the pressure in the space S1 decreases rapidly, and the pushing-down force also decreases rapidly.
Can freely move up and down.

Then, as shown in FIG. 4C, when the first switching valve SV1 is excited and the second switching valve SV2 is demagnetized, the output of the low pressure setting regulator RL outputs the first switching valve SV1. P port, A port and second switching valve SV
2 through the R port and the A port of the first space S1.
Communicate with Then, the low-pressure L compressed air is supplied, and the diaphragm DP is pushed downward by a relatively small pushing force. In this means, the low pressure setting regulator R
The bonding load is appropriately set according to the set value of L (see FIG. 5).

Next, a bonding method using this bonding head will be described with reference to FIG. In FIG. 6, the horizontal axis is time t. The vertical axis represents the height from the upper surface of the lead frame LF to the lower surface of the electronic component P in FIG. 6 (a), the speed of the movable part 20 in FIG. 6 (b), and the switching in FIGS. 6 (c) and (d). Excitation of valves SV1 and SV2
In the demagnetized state, the pressure in the first space S1 (proportional to the pressing force by the diaphragm DP) is shown in FIG.

At times t0 to t1, the first and second
Demagnetize both of the switching valves SV1 and SV2 of
The moving means 30 is driven (see FIG. 1) while maintaining the pressure in 1 at the high pressure H, and the support mechanism 10 and the movable mechanism 20 are lowered at a high speed. In this state, as shown in FIG.
Since the electronic component P sucked by the suction portion 22 is located significantly above the lead frame LF, there is no risk of breakage even when the electronic component P is lowered at a high speed, and the lower surface of the diaphragm plate 23 is pressed against the bottom surface of the concave portion 11a. Therefore, the movable mechanism 20 such as the suction unit 22 descends integrally with the support mechanism 10 such as the holder 11.

Next, between times t1 and t2, the first and second
Are excited, the space S1 is communicated with the vacuum portion V, and the pressure and the pressing force are rapidly reduced from the high pressure H state. The communication with the vacuum portion V is performed in order to rapidly reduce the pressure in the space S1 and improve the response speed.

Next, from time t2 to t3, only the second switching valve SV2 is demagnetized, and the space S1 is maintained at the low pressure L.
Here, as shown in FIG. 5, at time t3, the electronic component P is grounded to the lead frame LF. At this time, the electronic component P
And the suction part 22 receives a reaction force from the lead frame LF. However, since the pressure in the space S1 is low,
The external force pressing the movable mechanism 20 against the support mechanism 10 is weakened. Therefore, the movable mechanism 20 can slightly rise with respect to the support mechanism 10. Therefore, the reaction force is small and smoothly absorbed, and the electronic component P can be quietly grounded to the lead frame LF.

Therefore, like the conventional means using only the spring K, after the electronic component P is grounded to the lead frame LF, the suction portion 22 vibrates vigorously (jumping phenomenon) up and down to damage the electronic component P. Never.

Next, from time t3 to t4, FIG.
As shown by the solid line, the pressure in the space S1 is maintained at a low pressure L,
Alternatively, if the bonding load is insufficient, the low-pressure setting regulator RL may be driven to gradually increase the low-pressure side pressure (see the broken line). Thereby, the electronic component P can be firmly bonded to the lead frame LF.

Then, from time t4 to t5 to t6, the first and second switching valves SV1 and SV2 are demagnetized, the pressure in the space S1 is maintained at a high pressure H, the moving means 30 is driven, and the support mechanism 10 and The movable mechanism 20 is raised.

[0052]

As described above, according to the present invention, by adjusting the pressure of the compressed air applied to the diaphragm, it is possible to smoothly change the bonding load without replacing parts. In addition, by reducing the external force when the suction section is about to descend, the shock applied to the electronic component can be reduced, and damage to the electronic component can be prevented.

[Brief description of the drawings]

FIG. 1A is a perspective view of a die bonding apparatus according to one embodiment of the present invention. FIG. 1B is a partially exploded view of a bonding head of the die bonding apparatus according to one embodiment of the present invention.

FIG. 2 is an assembly diagram of a bonding head of the die bonding apparatus according to one embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a bonding head of the die bonding apparatus according to one embodiment of the present invention.

FIG. 4 is a circuit diagram of a bonding head control unit of the die bonding apparatus according to one embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a bonding head when the die bonding apparatus according to the embodiment of the present invention is about to descend most;

FIG. 6 is an explanatory diagram of an operation of the die bonding apparatus according to one embodiment of the present invention;

FIG. 7 is an exemplary view of a conventional bonding head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bonding head 11 Holder 11a Concave part 22 Suction part 23 Plate 23c Flange part AS Compressed air source DP Diaphragm P Electronic component RL Regulator for low pressure setting RH Regulator for high pressure setting W Wafer

Claims (1)

(57) [Claims] 1. A die bonding apparatus in which an electronic component is attracted to a suction portion of a bonding head to be picked up and mounted on a substrate, wherein the bonding head has a lifting rod having a suction portion at a lower portion for sucking the electronic component; Pressure adjusting means for adjusting the pressure of compressed air supplied from the compressed air source to the diaphragm, comprising: a diaphragm disposed above the rod; Wherein the pressing force of the lifting rod applied to the electronic component by the pressure of the compressed air applied to the lifting rod via the diaphragm is adjusted.