JP2630316B2 - Paste application equipment for pellet bonding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying a paste for pellet bonding which is suitable for bonding pellets of semiconductor parts, ceramic parts and the like to a substrate.

[0002]

2. Description of the Related Art In a pellet bonding apparatus for manufacturing electronic parts, a paste (adhesive) is applied on a die pad of a substrate (lead frame), and semiconductor pellets are bonded on the paste. At this time, in order to ensure the performance of the electronic component, the paste must be uniformly applied to the entire back surface of the pellet, and it is not appropriate that bubbles remain in the paste or that the distribution of the paste is uneven. .

FIG. 7 is a schematic view showing a conventional paste coating apparatus. A slide block 2 is slidably supported on the base 1, a syringe holder 3 is coupled to the slide block 2, and a syringe 5 filled with a paste 4 is fixed to the syringe holder 3. The syringe 5 has a discharge nozzle 6 and is connected to an air pipe 7 for supplying air at a constant pressure. The base 1 is provided with a drive motor 8. Driving motor 8 is one of the followers cam 9
And the syringe holder 3 is moved up and down via the cam roller 10 so that the discharge nozzle 6 of the syringe 5 is
Move closer / separate to

That is, in the above-mentioned conventional paste applying apparatus, the follower cam 9 is rotated by the drive motor 8 and the discharge nozzle 6 of the syringe 5 fixed to the syringe holder 3 is used.
Moves down to apply the paste 4 to the substrate 11. afterwards,
The discharge nozzle 6 rises and the origin sensor 12 detects the sensor dog 1
By shutting off at 3, the drive motor 8 stops and one cycle ends. FIG. 8 shows the discharge nozzle 6
4 is a timing chart of the up-down operation of the follower cam 9. As shown in the timing chart, when the discharge signal sensor 15 is turned on by the sensor cam 14 while the discharge nozzle 6 is descending, a discharge signal is transferred to a dispenser controller (not shown), and the dispenser controller operates to keep the discharge signal from the air pipe 7 to the syringe 5 constant. Air at a pressure is supplied for a certain time, and the paste is discharged to the tip of the discharge nozzle 6 by the air pressure.

[0005]

However, in the above-mentioned conventional paste applying apparatus, the operation timing of the discharge nozzle 6 is uniquely determined by the follower cam 9.

Therefore, as long as the same follower cam 9 is used,
Even if the viscosity of the paste or the dimensions of the pellets are changed, the application conditions, that is, the descending / elevating speed of the discharge nozzle 6, and the stop time are constant, so that the paste is liable to be scattered, the application unevenness, etc., and is stable and uniform. The paste application state cannot be obtained.

When the paste is applied to the substrate 11 by lowering the discharge nozzle 6, the tip of the discharge nozzle 6 is
The determination of the gap amount of 1 is also important for obtaining a stable and uniform paste application state that does not cause stringing or the like, but the adjustment of the gap amount requires that the adjustment bolt 16 be manually screwed. Lack of speed.

Further, in order to find out the optimum application conditions with respect to the change in the viscosity of the paste and the size of the pellet, the operation timing of the follower cam 9 is changed in order to change the operation timing of the follower cam 9.
Must be changed. For this reason, in order to find out the optimal application conditions, it is necessary to prepare several types of follower cams and carry out experiments, resulting in poor workability.

SUMMARY OF THE INVENTION It is an object of the present invention to stabilize the paste application state in a short time and to obtain a pellet bonding product having a good yield.

[0010]

According to a first aspect of the present invention, a discharge nozzle for a paste for pellet bonding is moved toward or away from a substrate, and the paste discharged from the discharge nozzle is coated on the substrate. In a pellet bonding paste application apparatus, a drive device capable of controlling the speed of moving the discharge nozzle with respect to the substrate, an elapsed time from the start of paste application, and a position of the discharge nozzle corresponding to the elapsed time. A setting device for setting, and a control device for controlling the driving device based on a set value set in the setting device and controlling a movement pattern of the discharge nozzle.

According to a second aspect of the present invention, in the first aspect, the driving device is a linear motor.

According to a third aspect of the present invention, in the first aspect, the driving device is a rotary servomotor.

[0013]

The movement pattern of the discharge nozzle can be freely set and changed by changing the set value of the setting device. For this reason, for example, even when the movement pattern of the ejection nozzle is to be changed according to the paste viscosity, it is only necessary to change the set value, so that the ejection nozzle movement pattern optimal for the viscosity can be easily obtained. Therefore, it is possible to stabilize the paste application state easily and in a short time, and to obtain a pellet bonding apparatus with a good yield.

[0014]

FIG. 1 is a schematic view showing a paste coating apparatus according to a first embodiment of the present invention, FIG. 2 (A) is a side sectional view showing a coating state by a one-point nozzle, and FIG. 2 (B) is FIG. 3A is a plan view of a main part, FIG. 3A is a side cross-sectional view showing an application state using a multipoint nozzle, FIG. 3B is a plan view of a main part of FIG.
Is a timing chart showing the operation of the nozzle.

A slide block 22 is slidably supported on a base 21 of the paste application apparatus 20, and a syringe holder 23 is coupled to the slide block 22,
A syringe 25 filled with a paste 24 is fixed to the syringe holder 23. The syringe 25 is the discharge nozzle 2
6 and an air pipe 27 for supplying air at a constant pressure is connected.

The paste application device 20 includes a linear servomotor 28, a control device 29, and a setting device 30. The linear servo motor 28 is capable of speed control,
By driving the syringe holder 23, the discharge nozzle 26 is moved to the substrate 3
Move up and down with respect to 1. The control device 29 controls the driving state of the linear servomotor 28 based on the setting value of the setting device 30 and digitally controls the moving state of the discharge nozzle 26, as described later in detail.

The paste application device 20 includes an origin sensor 32 for detecting the rising end of the syringe holder 23, and a sensor dog 33 for operating the origin sensor 32.

That is, in the paste application device 20, when the substrate 31 is transported by a lead frame transport device (not shown) and stopped and positioned at the paste application position, and the positioning completion signal is transferred to the control device 29. The control device 29 starts driving the linear servomotor 28.
The control device 29 controls the drive of the linear servomotor 28 at the operation timing set in advance by the setting device 30.
As shown in the figure, the discharge nozzle 26 descends 1, descends 2, stops,
The operation of one cycle of ascent is given to apply the paste to the substrate 31. The control device 29 controls the drive of the linear servomotor 28 so that the discharge nozzle 26 descends by a preset stroke S1, and forms a predetermined gap amount a between the discharge nozzle 26 located at the descending end and the substrate 31. I do.

Hereinafter, the operation timing of the discharge nozzle 26 will be described in detail. t1 falls at a high speed in the time of fall 1. t2 falls at a low speed in the time of falling 2. t3 is the stop time at the descending position and the time for applying the paste, t4
Is the rise time. t is the total time from t1 to t4, which is the elapsed time of one cycle from the start of the paste application. s1
Is the total descending stroke of the discharge nozzle 26, and is determined based on the gap amount a formed between the discharge nozzle 26 and the substrate 31. s2 is a descending 2 stroke descending at a low speed.

The above driving parameters t1 to t of the discharge nozzle 26
4, s1, and s2 can be digitally variably set by, for example, operating switches with the setting device 30, and are numerically input to the control device 29 in advance and used as drive control data of the linear servomotor 28. That is, the drive parameters t1 to t4, s1, and s2 of the discharge nozzle 26 are changed in whole or in part according to a change in the viscosity of the paste and / or the dimensions of the pellets, as shown in FIG. , So that a stable and uniform paste application state can be obtained.

Here, if the speed of the descending 2 is high when the viscosity of the paste is low, the paste may scatter on the substrate 31. If the stop time t3 is too short, the paste application state may be uneven. If the gap amount a between the discharge nozzle 26 and the substrate 31 is large, when the discharge nozzle 26 rises, stringing of the paste occurs between the tip of the discharge nozzle 26 and the substrate 31.

The speed of the lowering 1 and the speed of the rising are not directly related to the quality of the paste application state, but the time t of one cycle
Since it is shortened and related to the index speed of the entire pellet bonding apparatus, the maximum speed is set so that the paste applying apparatus 20 can operate smoothly without vibration.

The time t of one cycle is determined by the distribution of the paste application time within the index time of the pellet bonding apparatus.
It is determined by t4, s1, and s2. Therefore, by optimally setting the driving parameters t1 to t4, s1, and s2, the time t can be shortened, the speed of the entire pellet bonding apparatus can be increased, and a stable and efficient pellet bonding apparatus can be provided.

The control device 29 transfers a discharge signal to a dispenser controller (not shown) in the middle of the downward movement 1 of the discharge nozzle 26. Thus, the dispenser controller controls the magnitude of the pressure of the compressed air supplied from the air pipe 27 to the syringe 25 and the pressurization time. The control of the magnitude of the pressure and the pressurization time by the dispenser controller can be numerically set using the control device 29 and the setting device 30.

Next, the operation of the above embodiment will be described. According to the above embodiment, the drive state of the linear servomotor 28 is set to the set value (drive specification t) set in the setting device 30.
1 to t4, s1, s2), the control device 29 controls the movement pattern of the discharge nozzle 26, that is, the moving speed of the discharge nozzle 26 and the descending position according to the viscosity of the paste and the dimensions of the pellet. Optimum control of the stop time, the gap amount between the discharge nozzle 26 and the substrate 31, the application time,
The discharge nozzle 26 can be driven under optimal application conditions. The movement pattern of the discharge nozzle 26 can be freely set and changed by an operation of changing the set values (t1 to t4, s1, s2) of the setting device 30. Therefore, even when the movement pattern of the discharge nozzle 26 is to be changed in accordance with, for example, a change in the viscosity of the paste and / or the size of the pellet, the set values (t1 to t4, s1,
Since it is only necessary to change all or part of s2), it is possible to easily obtain a movement pattern of the discharge nozzle 26 that is optimal for the viscosity and the like.

Therefore, the paste is applied under the optimum application conditions according to the change in the viscosity of the paste and the dimensions of the pellet.
It is possible to obtain a stable and uniform paste application state without scatter of the paste and no stringing.

[0027]

Further, since the driving state of the discharge nozzle 26 can be easily adjusted, it is possible to easily find the optimum application conditions for the change in the viscosity of the paste and the dimensions of the pellet.

That is, according to the above-mentioned embodiment, the paste application state can be easily stabilized, and a semiconductor product having a good yield can be obtained.

The discharge nozzle 26 of the paste application device 20 is a one-point type as shown in FIGS. 2 (A) and 2 (B), and FIG.
Any of the multi-point formulas shown in FIG. 31A is a die pad.

FIG. 5 is a schematic view showing a paste coating apparatus according to a second embodiment of the present invention.

This embodiment differs from the first embodiment in that a rotary servomotor (DC servomotor, AC servomotor, stepping motor, etc.) 41 and a feed screw 42 are used instead of the linear servomotor 28. It is. 43 and 44 are toothed pulleys, 45 is a toothed belt, 46
Is a nut. The servomotor 41 rotates the feed screw 42 and vertically moves the nut 46 with which the feed screw 42 is screwed, thereby vertically moving the syringe holder 23 to which the nut 46 is attached. The servo motor 41 reverses when the discharge nozzle 26 is switched between rising and falling.

FIG. 6A is a schematic view showing a paste coating apparatus according to a third embodiment of the present invention, and FIG. 6B is a front view showing a constant velocity cam.

This embodiment differs from the first embodiment in that a rotary servomotor 51 and a constant speed cam 52 are used instead of the linear servomotor 28. 53 is a roller pin, 54 is a cam roller, and 55 is a tension spring.
The rotary servomotor 51 rotates a cam 52 having a constant speed cam curve, and moves the syringe holder 23 up and down via a cam roller 54 driven by the cam 52. The servo motor 51 reverses when the discharge nozzle 26 is switched between rising and falling.

The present invention can be applied to a pellet coating apparatus for bonding pellets such as ceramic parts to a substrate.

[0036]

As described above, according to the present invention, the paste application state can be stabilized easily and in a short time, and a pellet bonding product having a good yield can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a paste application device according to a first embodiment of the present invention.

FIG. 2A is a side sectional view showing an application state by a one-point nozzle, and FIG. 2B is a plan view of a main part of FIG. 2A.

3A is a side sectional view showing an application state by a multipoint nozzle, and FIG. 3B is a plan view of a main part of FIG. 3A.

FIG. 4 is a timing chart showing the operation of the nozzle.

FIG. 5 is a schematic view showing a paste application device according to a second embodiment of the present invention.

FIG. 6A is a schematic view showing a paste application apparatus according to a third embodiment of the present invention, and FIG. 6B is a front view showing a constant velocity cam.

FIG. 7 is a schematic diagram showing a paste application apparatus according to a conventional example.

FIG. 8 is a timing chart showing the operation of a nozzle in a conventional example.

[Explanation of symbols]

 26 Discharge Nozzle 28 Linear Servo Motor (Drive Device) 29 Controller 30 Setting Device 31 Substrate 41 Rotary Servo Motor (Drive Device) 51 Rotary Servo Motor (Drive Device)

Claims (3)

(57) [Claims] 1. A pellet bonding paste coating apparatus for moving a discharge nozzle of a pellet bonding paste toward / away from a substrate and coating the paste discharged from the discharge nozzle on the substrate. A driving device capable of controlling the speed of movement with respect to the setting device, a setting device for setting an elapsed time from the start of the paste application and a position where the ejection nozzle should be corresponding to the elapsed time, and a setting set in the setting device. A control device for controlling the driving device based on the value to control the movement pattern of the discharge nozzle. 2. The apparatus for applying paste for pellet bonding according to claim 1, wherein said driving device is a linear motor. 3. The apparatus for applying paste for pellet bonding according to claim 1, wherein said driving device is a rotary servomotor.