JP3982915B2 - Pellet bonding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pellet bonding apparatus.
[0002]
[Prior art]
In a semiconductor pellet bonding apparatus, an island portion of a lead frame is adsorbed and held on a bonding stage as a support block at a paste application position or a pellet bonding position. When the lead frame is transported, the bonding stage is positioned at a standby position where it does not interfere with the lower surface of the transported lead frame. When the predetermined island portion is positioned at the paste application position or the pellet bonding position, the island portion is adsorbed. Ascending to the standard suction position, the island portion is sucked and held by generating a suction force in the vacuum suction hole.
[0003]
[Problems to be solved by the invention]
By the way, since the island part is suspended from the lead frame by a thin support piece called a tie bar, its position is likely to vary in the direction perpendicular to the surface of the island part, that is, in the height direction. For this reason, in an operating state where the bonding stage is positioned at a standard suction position determined corresponding to the standard height level that should be the standard of the island portion, the island portion is displaced above the standard height level. If there is a gap, a gap may be formed between the bonding stage and the island portion, and the island portion may not be adsorbed by the bonding stage.
[0004]
If the island part cannot be adsorbed by the bonding stage at the paste application position, the island part will float above the standard height level. For this reason, the gap g ₁ between the application nozzle set at the application work position at the time of applying the paste and the island portion becomes smaller than the appropriate interval g ₂ (FIG. 2A), and a predetermined amount of paste is applied to the island portion. There is a possibility that it cannot be performed (FIG. 2C). That is, a part of a predetermined amount of paste discharged from the coating nozzle protrudes from the gap between the coating nozzle and the island portion, and is not applied to the island portion but is attached to the periphery of the coating nozzle and carried away. When the amount of paste applied is less than a predetermined amount, a predetermined adhesive force cannot be obtained and the pellets may be peeled off.
[0005]
If the island part cannot be adsorbed by the bonding stage at the bonding position of the pellet, the island part floats above the standard height level, and the pellet that is adsorbed and lowered by the adsorption nozzle during bonding is applied to the island part. When the collision occurs (via the applied paste), the island part is struck downward by the impact (the amount lifted with respect to the bonding stage), and the paste applied to the island part comes apart from the bottom surface of the pellet for a moment and comes into contact again. As a result, there is a possibility that bubbles A are generated in the paste (FIG. 3). When bubbles are generated in the paste, the bubbles may expand when heated in a subsequent wire bonding step or the like, resulting in cracking and peeling of the pellets.
[0006]
The first object of the present invention is to prevent the occurrence of variations in the amount of paste applied to the island portion during paste application.
[0007]
The second problem of the present invention is to prevent bubbles from being generated in the paste interposed between the island part and the pellet during bonding.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the pellet bonding apparatus for applying a paste to the island portion of the lead frame and bonding the pellet to the island portion via the paste, the island portion can be sucked and held at the paste application position. The support block, the block drive unit that moves between the standby position where the support block does not interfere with the lead frame and the position where the island part is sucked, and the support block is moved to the island part when the island part is sucked by the support block. And a controller that controls the block drive unit so that the island part is adsorbed by moving it to a position higher than the standard height level of the island, and then the support block is positioned at the standard height level of the island part. It was made to become.
[0009]
The present invention according to claim 2 is capable of adsorbing and holding the island part at the pellet bonding position in a pellet bonding apparatus that applies paste to the island part of the lead frame and bonds the pellet to the island part via the paste. The support block, a block drive unit that moves between a standby position where the support block does not interfere with the lead frame, and a position where the island portion is sucked, and when the island portion is sucked by the support block, the support block is moved to the island. A control unit that controls the block drive unit so that the island unit is adsorbed by moving it to a position that is higher than the standard height level of the unit by suction, and then the support block is positioned at the standard level of the island unit. It has been made to become.
[0010]
According to a third aspect of the present invention, in a pellet bonding apparatus for applying a paste to an island part of a lead frame and bonding a pellet to the island part via the paste, the paste is applied from a paste application position to a pellet bonding position. A support block that is installed and sucks and holds the island part, which is the paste application position, and sucks and holds other island parts at the pellet bonding position, a standby position that does not interfere with the lead frame, and an island part. When the island part is sucked by the block drive unit that moves between the sucking position and the supporting block, the supporting part is moved to a position higher than the standard height level of the island part by a predetermined amount to suck the island part. After that, the support block is moved to the standard height level of the island. As positioned in Le, is obtained in such a manner that a control unit for controlling the block driver.
[0011]
[Action]
According to the present invention of claim 1, the following effect (1) is obtained.
(1) When the island part is adsorbed by the support block installed at the paste application position, the island part is adsorbed by moving the support block to a level higher by a predetermined amount than the standard height level of the island part. Therefore, even when the island portion is displaced above the standard height level, the island portion can be reliably adsorbed to the support block.
[0012]
According to the second aspect of the present invention, there is the following effect (2).
(2) When the island part is sucked by the support block installed at the pellet bonding position, the island part is sucked by moving the support block to a level higher than the standard height level of the island part by a predetermined amount. Therefore, even when the island portion is displaced above the standard height level, the island portion can be reliably adsorbed to the support block.
[0013]
According to the third aspect of the present invention, the following effect (3) is obtained.
(3) When the island part is adsorbed by the support block installed from the paste application position to the pellet bonding position, the support block is moved to a level higher than the standard height level of the island part by a predetermined amount. Adsorb part. Therefore, even when the island portion is displaced above the standard height level, the island portion can be reliably adsorbed to the support block.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram showing a pellet bonding apparatus, FIG. 2 is a schematic diagram showing the effect of the floating of the island part on the application of the paste, and FIG. 3 is a schematic diagram showing the influence of the floating of the island part on the bonding of the pellet. .
[0015]
As shown in FIG. 1, the pellet bonding apparatus 10 transports the lead frame 1 along the transport rail 11, applies the paste 3 to the island portion 2 of the lead frame 1 positioned at the paste application position, and positions it at the bonding position. The pellet 4 is bonded to the island portion 2 of the lead frame 1 through the paste 3. Here, the lead frame 1 suspends the island portion 2 with a thin support piece 1A called a tie bar. The paste 3 is supplied by the application nozzle 12 (FIG. 2), and the pellet 4 is supplied by the suction nozzle 13 (FIG. 3).
[0016]
However, the pellet bonding apparatus 10 includes a bonding stage 21 as a support block provided from the paste application position to the pellet bonding position. The bonding stage 21 can hold the island portion 2 by suction at each of the paste application position and the pellet bonding position. Specifically, the bonding stage 21 includes a vacuum suction hole 22A corresponding to the paste application position and a vacuum suction hole 22B (not shown) corresponding to the pellet bonding position. A vacuum generator such as a vacuum pump is connected to generate suction force in the suction holes 22A and 22B.
[0017]
In the pellet bonding apparatus 10, the bonding stage 21 is driven as a block driving unit that drives between a standby position that does not interfere with the lead frame 1 when the lead frame 1 is transported and a suction position that sucks the island part 2. The stage drive unit 31 is provided. Specifically, the stage drive unit 31 supports a cam follower 34 provided on the bonding stage 21 by a cam 33 rotated by a motor 32 and controls the rotation amount of the motor 32 to raise and lower the bonding stage 21. The position can be adjusted to an arbitrary height. A motor 32 that can control the amount of rotation such as a stepping motor can be used, and a cam 33 that has a constant velocity cam curve can be used.
[0018]
Here, the pellet bonding apparatus 10 includes a control unit 41 that controls the stage driving unit 31. When the controller 41 sucks the island part 2 with the bonding stage 21, (1) the bonding stage 21 is moved by a predetermined amount ΔL from the standby position (FIG. 1A) than the standard height level of the island part 2. Ascend to the high pushing suction position and suck the island part 2 as if it was pushed in (Fig. 1 (B)). (2) After that, the bonding stage 21 corresponds to the standard height level of the island part 2 The motor 32 of the stage drive unit 31 is driven and controlled so as to be positioned.
[0019]
At this time, the setting unit 42 inputs the pushing suction position (1) and the standard suction position (2) to the control unit 41 according to the type of the lead frame 1. The push-in suction position (push adjustment amount ΔL from the standard suction position) is determined based on the amount of variation in the height direction position obtained experimentally in advance for the island portion 2 of the lead frame 1.
[0020]
The setting unit 42 detects the height direction positions of the lead frame 1 and the island portion 2 before the lead frame 1 is carried into the paste application position and the pellet bonding position. It is also possible to determine the pushing suction position and the standard suction position.
[0021]
Therefore, the pellet bonding apparatus 10 operates as follows.
(1) The island portion 2 of the lead frame 1 is positioned at the paste application position. At this time, the bonding stage 21 is in the standby position, and no suction force is generated in the suction hole 22A (FIG. 1A).
[0022]
(2) The control unit 41 controls the motor 32 of the stage drive unit 31 to rotate in the forward direction, and raises the bonding stage 21 to a pushing suction position that is higher than the standard height level of the island part 2 by a predetermined amount. A suction force is generated in the hole 22A. Thereby, the bonding stage 21 is surely adsorbed as if the island portion 2 is pushed in (FIG. 1B).
[0023]
(3) The control unit 41 controls the motor 32 of the stage drive unit 31 to rotate in the reverse direction, and positions the bonding stage 21 at the standard suction position corresponding to the standard height level of the island unit 2 (FIG. 1C). In this state, the paste 3 is applied to the island part 2 from the application nozzle 12 (FIG. 2B). Thereafter, the control unit 41 lowers the bonding stage 21 to the standby position.
[0024]
(4) The island part 2 of the lead frame 1 is positioned at the bonding position of the pellet. At this time, the bonding stage 21 is in the standby position, and no suction force is generated in the suction hole 22B.
[0025]
(5) The control unit 41 controls the motor 32 of the stage drive unit 31 to rotate in the forward direction, and raises the bonding stage 21 to a pushing suction position that is higher than the standard height level of the island part 2 by a predetermined amount. A suction force is generated in the hole 22B. Thereby, the bonding stage 21 is surely adsorbed as if the island part 2 is pushed in.
[0026]
(6) The control unit 41 controls the motor 32 of the stage drive unit 31 to rotate in the reverse direction, and positions the bonding stage 21 at the standard suction position corresponding to the standard height level of the island unit 2. In this state, the pellet 4 supplied by the suction nozzle 13 is bonded to the island portion 2 (via the paste 3 described above). Thereafter, the control unit 41 lowers the bonding stage 21 to the standby position.
[0027]
In the pellet bonding apparatus 10, the preceding and following island portions 2 are sequentially positioned at the paste application position and the pellet bonding position, and the above-described (1) to (3) for the subsequent island portion 2 are as follows. The above (4) to (6) for the preceding island 2 are processed in parallel.
[0028]
Therefore, according to the present embodiment, there are the following operations.
(1) When the island part 2 is adsorbed by the bonding stage 21 installed from the application position of the paste 3 to the bonding position of the pellet 4, the bonding stage 21 is raised by a predetermined amount from the standard height level of the island part 2. The island part 2 is adsorbed by moving to the level. Therefore, even when the island portion 2 is displaced above the standard height level, the island portion 2 can be reliably attracted to the bonding stage 21.
[0029]
(2) By the above (1), the distance between the application nozzle 12 set at the application work position at the time of applying the paste and the island portion 2 is set to an appropriate interval g ₂ (FIG. 2A). A predetermined amount of paste 3 can be applied to the island portion 2 (FIG. 2B).
[0030]
(3) Due to the above (1), even if the pellet 4 adsorbed and lowered by the adsorption nozzle 13 at the time of bonding collides with the island part 2 via the paste 3, the island part 2 does not float on the bonding stage 21. Since it is supported and does not bounce downward, it is possible to prevent bubbles from forming in the paste 3.
[0031]
Product yield can be improved by (2) and (3) above.
[0032]
Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. Is included in the present invention. For example, in the implementation of the present invention, the pellet bonding apparatus includes the bonding stage of the present invention only at the pellet application position, the pellet bonding apparatus of the present invention only at the pellet bonding position, or the paste application position and the pellet bonding position. Each of them may be provided with the bonding stage of the present invention independently of each other.
[0033]
In the implementation of the present invention, the stage driving unit is not limited to using a cam, and may use other means such as a screw.
[0034]
The bonding stage 21 may have a heater and heat the lead frame to a predetermined temperature at a paste application position or a bonding position.
[0035]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent variation in the amount of paste applied.
[0036]
Moreover, according to this invention, it can prevent that a bubble generate | occur | produces in a paste.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a pellet bonding apparatus.
FIG. 2 is a schematic diagram showing the influence of the floating of the island part on the application of paste.
FIG. 3 is a schematic diagram showing the effect of floating of an island part on pellet bonding.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lead frame 2 Island part 3 Paste 4 Pellet 10 Pellet bonding apparatus 21 Bonding stage 22A, 22B Suction hole 31 Stage drive part 41 Control part

Claims (3)

In a pellet bonding apparatus that applies paste to the island part of the lead frame and bonds the pellet to the island part via the paste,
A support block capable of adsorbing and holding the island part at the paste application position;
A block driving unit that moves between a standby position where the support block does not interfere with the lead frame and a position where the island part is adsorbed;
When the island part is sucked by the support block, the support block is moved to a position higher than the standard height level of the island part by a predetermined amount to suck the island part, and then the support block is set to the standard height level of the island part. A pellet bonding apparatus comprising: a control unit that controls the block driving unit so as to be positioned. In a pellet bonding apparatus that applies paste to the island part of the lead frame and bonds the pellet to the island part via the paste,
A support block capable of adsorbing and holding the island at the pellet bonding position;
A block driving unit that moves between a standby position where the support block does not interfere with the lead frame and a position where the island part is adsorbed;
When the island part is sucked by the support block, the support block is moved to a position higher than the standard height level of the island part by a predetermined amount to suck the island part, and then the support block is set to the standard height level of the island part. A pellet bonding apparatus comprising: a control unit that controls the block driving unit so as to be positioned. In a pellet bonding apparatus that applies paste to the island part of the lead frame and bonds the pellet to the island part via the paste,
A support block that is installed from the paste application position to the pellet bonding position, adsorbs and holds the island part that is the paste application position, and can adsorb and hold other island parts at the pellet bonding position;
A block driving unit that moves between a standby position where the support block does not interfere with the lead frame and a position where the island part is adsorbed;
When the island part is sucked by the support block, the support block is moved to a position higher than the standard height level of the island part by a predetermined amount to suck the island part, and then the support block is set to the standard height level of the island part. A pellet bonding apparatus comprising: a control unit that controls the block driving unit so as to be positioned.

Images