JPS605057B2 - wire bonding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire bonding device (wire bonder).

2. Description of the Related Art In the manufacture of semiconductor devices, integrated circuit devices, etc., there is wire bonding work in which electrodes (bonding pads) of circuit elements (bullet) and external leads are connected with wires.

For this wire bonding work, for example, a wire bonder having the structure shown in FIG. 1 is used. That is, a capillary 5 holding a wire 4 and facing a belt 2 and a lead 3 fixed on a table 1 is connected to an X
It is attached to the Y table 7. This XY table 7 is movable in plane XY directions. Further, the arm 6 swings around a support shaft 8 to move the lower end of the capillary 5 up and down. A light support arm 9 is attached to the XY table 7, and a spot projector 10 is fixed to the tip of the light support arm 9. The light emitted from this spot projector 10 is designed to reach the lower end extension of the capillary 5.
On the other hand, the lower end of the capillary 5, the beret 2 and the lead 3
A microscope 11 for observing is mounted on an XY table 12 for moving the field of view, which is movable in a plane direction. Further, an ITV camera 13 is attached to the microscope 11, and its image is displayed on a television monitor 14. In wire bonding, a spot with a diameter of 100 m is projected onto the surface of the beret, and the worker
While observing the image with V, move the XY table 7 so that the spotlight matches the bonding pad of the pellet 2, and when it matches, the position is electrically memorized. This position is memorized at two specific bonding pad locations, and the amount of positional deviation of the pellet 2 with respect to the lead 3 is △×,
Δy and Δa are calculated to determine the position of each bonding pad, and based on this, the XY table 7 is automatically moved in sequence to perform wire bonding. By the way, in this device, it is assumed that the capillary is located directly above the bonding pad by matching the position of the spot light on the bullet with the bonding pad of the bullet.

However, since the spot light emitter is obstructed by the capillary, the light is emitted from diagonally above the bonding pad. Therefore, the intersection of the spot light and the extended line of the capillary is at one point, and this position (
When the beret surface is located at a height of 1.5 cm, the surface irradiated with the spotlight is located directly below the capillary. therefore,
If the thickness of the pellet or the board to which it is attached varies, and if it is thicker or thinner than the specified thickness, the height of the pellet surface will be higher or lower than the specified height. . Therefore, even if the spot light irradiation surface hits the bonding pad, the bonding pad will not be located directly under the capillary, and the incorrect position will be memorized and calculated as the bonding pad position, so the actual wire This means that bonding cannot be performed accurately. In addition, with this wire bonder, it is desirable that the surroundings be dark in order to check the spot light, but this has the disadvantage that it is difficult to monitor wire bonding.

Furthermore, since the wire bonder uses a high-magnification microscope to perform highly accurate positioning, the field of view of the microscope becomes narrow.

As a result, the spot light irradiation surface is removed from the field of view of the microscope, so an XY table for moving the field of view is required to move the microscope, but the wire bonder becomes complicated and
Having a human operator operate the XY table for moving the field of view each time positioning has drawbacks such as difficulty in managing a large number of wire bonders at once. Therefore, an object of the present invention is to accurately measure the position of the beret, determine the accurate bonding position, perform reliable wire bonding, and monitor the wire bonding condition regardless of variations in the thickness of the beret or the substrate. An object of the present invention is to provide a wire bonder that is easy to use.

Another object of the present invention is to provide a wire bonder that can monitor positioning and bonding conditions without moving a monitoring microscope.

The present invention will be explained in detail below with reference to Examples. FIG. 2 shows an embodiment of the wire bonder of the present invention.

As shown in the figure, a lead 16 is provided on the upper left side of the pedestal 15.
A table 18 on which the Yabelet 17 is mounted is fixed, and an
Y table 19 is arranged. Said XY table 1
An arm 21 that is vertically swingable is attached to 9 via a support shaft 20. A cylindrical capillary 23 that holds a wire 22 is vertically attached to the tip of this arm 21. Further, a control mechanism (not shown) acts on the end of the arm 21 to swing the arm 21 up and down. Further, a support arm 24 is attached to the XY table 19.

The tip of this support arm 24 protrudes in front of the capillary 23 at the tip of the arm 21, and a microscope 25 is attached to the tip so as to look down on the pellet 17 and lead 16 directly below. Further, a light 26 is attached to the outside of the microscope 25 to illuminate the table 18 brightly. Further, the center of the microscope 25 and the center of the capillary 23 are eccentric by e, and this eccentricity e is stored in a control system (not shown).
On the other hand, an ITV camera 27 for measurement is connected to the microscope 25, and an image taken by the ITV camera 27 for measurement is displayed on a screen 29 of a television monitor 28.

Furthermore, a square reticle 30 is displayed on the screen, similar to the square bonding pad on the pellet 17. On the other hand, diagonally above the table 18 is a monitoring ITV that monitors the entire table 8.
A camera 31 is arranged, and the image of the monitoring ITV camera 31 is displayed on the screen 29 of the television camera 28 instead of the measurement ITV camera 27 by switching the lever 33 of the changeover switch 32. It has become.

Next, the wire bonding operation will be explained.

First, an image of the measurement ITV camera 27 is projected onto the screen 29 of the TV monitor 28, and a predetermined square bonding pad of the bellet 17 is connected to the square reticle 3 of the screen 29.
The XY table 19 is operated so as to match 0'. Then, use the prescribed bonding pad and takele 3.
If 0 matches, this position is automatically stored in a control system memory (not shown). Further, in the same manner, another bonding pad is matched with the tickle 30, and this position is stored in the memory. Then, the positional relationship between the pellet 17 and the reed 16 is automatically calculated by the computer of the control system based on the information obtained from the two position measurements and the information stored in the memory in advance, and each bonding position is determined. Thereafter, the XY table is automatically operated in correspondence with each bonding position to automatically perform wire bonding. According to this type of wire bonding, since the mark (predetermined bonding pad) on the beret is viewed from directly above, the thickness of the beret, the leads, and the substrate (lead frame) that supports the beret is Even if there are variations in the marks, positional deviations in mark measurement do not occur as in the conventional method.

As a result, accurate measurements can be made and wire bonding can be performed accurately and reliably. Further, according to this wire bonding, since the square bonding pad is simply superimposed on the square reticle of the screen of the television monitor, the work can be done quickly and easily, and even beginners can perform reliable wire bonding.

In addition, with this wire bonder, the table 1
In addition to brightening the entire upper surface of the screen, images from a surveillance ITV camera can be easily projected on the screen of a television monitor by operating the lever of a changeover switch. Therefore, wire bonding can be easily monitored. Furthermore, since there is no need to move the monitoring ITV camera at this time, one person can manage several such wireponders. moreover,
With this wire bonder, the pattern of the beret can be displayed on a television monitor, making it possible to check the pattern completely automatically.

Note that the present invention is not limited to the above embodiments. for example,
To align the beret and lead, use the reticle on the TV monitor as a crosshair, rotate the table on which the beret, etc. is placed so that it matches the crosshair, and adjust the amount of deviation of the measurement position by △x, △y, △0. (rotational deviation),
Bonding pads may also be calculated. Also, measurement IT
Instead of the V-camera, a lightweight solid-state imaging device such as a CCD or a line scanner may be placed directly on the XY table. In this case, since it is lightweight, the moving speed of the XY table can be increased, and the speed of wire bonding can be increased. Further, as another embodiment of the present invention, there is a wire bonder having the structure shown in FIGS. 3 and 4.

This wire bonder is designed to reduce the weight of the XY table and speed up wire bonding by removing the measurement ITV camera from the XY table. In addition, in the description, descriptions of mechanisms and articles similar to those of the previous embodiment will be omitted. However, the names and instruction numbers are the same as in the previous embodiment. In this wire bonder, as shown in FIG. 4, an X table 35 is placed on a Y table 34 that moves in the Y direction.

and. An arm 21 that supports the capillary 23 is attached to the X table 35. Also, on this X table 35 is an objective lens support arm (support arm).
36 is fixed. This objective lens support arm 36
The distal end portion of the lens barrel portion 37 forms a lens barrel portion 37, and an objective lens 38 made of a convex lens is attached to the lower end of the lens barrel portion 37 that extends perpendicularly to the table 18. Further, the objective lens 38 is attached at a position such that the focal point of the objective lens 38 is on the upper surface of the lead 16 and the bullet 17 placed on the table 18. Note that although the lens barrel portion 37 is fixed in the figure, it may be adjustable up and down. Further, a reflecting mirror 39 is provided at the top of the lens barrel portion 37.
is arranged to reflect the parallel light from the objective lens 38 in the X direction. This reflected light becomes a parallel light beam 40 in the X direction. Opening of the lens barrel part 37 ○ From 41 to the X/Y table 3
It is progressing on 5,34. On the other hand, the Y table 3
A mirror support arm 42 is fixed on the mirror support arm 4, and a reflecting mirror 43 is attached to the tip of the mirror support arm 42.

Then, this reflecting mirror 43 receives the parallel light beam 40 in the X direction, and as shown in FIG.
is reflected. On the other hand, the measurement ITV camera 27 is placed at a position where it can photograph the Y-direction parallel light east 44 moving in the Y-direction.
It is fixed independently from the X/Y tables 35 and 34.

According to such a wire bonder, since the pellet 16 is positioned in advance at the focal point of the objective lens 38, the light beams passing upward from the objective lens 38 proceed as parallel beams, and each reflector 39 , 43 into the field of view of the measurement ITV camera 27, and is displayed as a clear pattern on the screen of the television monitor 28.

Note that even if the X table 35 moves, the X table 35 does not move with respect to the Y direction of the mirror support arm 42, so the parallel light east 40 in the X direction does not come off the reflecting mirror 43 and always remains in a constant area. light reaches. Further, for the same reason, since the Y table 34 moves only in the direction toward and away from the ITV camera 27 for measurement, the Y-direction parallel light east 44 does not come out of the field of view of the ITV camera 27 for measurement.
Therefore, even if the X/Y table 35, 34 moves, the state on the table 18 is always captured by the measurement ITV camera 27. According to such embodiments,
Since the heavy ITV camera for measurement is removed from the X/Y table, the capillary can be moved at high speed, allowing high-speed wire bonding.

In this embodiment, in order to prevent the wire bonder from interfering with other components during operation, a relay lens may be provided in the middle of the optical system to increase the working distance. In the present invention, the objective lens 38 may be installed via a reflecting mirror 46 as shown in FIG.
Instead of a single convex lens, a combination lens with a concave lens or the like may be used as the objective lens. Further, instead of transmitting heat from the objective lens using a reflecting mirror, a fiber scope or the like may be used.

Furthermore, the wire bonder of the present invention can be specifically used as a nail head wire bonder or an ultrasonic wire bonder. As described above, according to the wire bonder of the present invention, the mark provided on the workpiece such as a pellet can be observed from directly above, so even if there are variations in the thickness of the workpiece such as the beret or lead, , accurate position measurement is possible.

Therefore, an accurate bonding position can be calculated and wire bonding can be performed accurately and reliably. Furthermore, according to the present invention, the entire surface of the work such as a bullet is brightly illuminated and the condition of the brackets is observed using a monitoring ITV, making it easy to monitor the bonding condition.

Further, images from the monitoring ITV camera and the measurement ITV camera can be easily displayed on a television monitor by operating a lever of a changeover switch. Therefore, one person can manage a large number of wire bonders, improving work efficiency. Further, according to the present invention, it is possible to reduce the weight of the drive section that performs wire bonding, so that the speed of the drive section, that is, the speed of wire bonding can be increased.

Therefore, many effects can be achieved, such as reducing the cost of the product.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a conventional wire bonding device;
Fig. 2 is a front view showing one embodiment of the wire bonding device of the present invention, Fig. 3 is a front view showing another embodiment, Fig. 4 is a plan view, and Fig. 5 is a modification of the installation of the objective lens. It is a figure which shows an example. 1...Tefle, 2...Beretsu 3...Lead, 4...
Wire, 5... Capillary, 6... Arm, 7...
...XY table, 8... Support shaft, 9... Light support arm, 10... Spot floodlight, 1
1... Microscope, 12... X for moving field of view
Y table, 1 3... ITV camera, 1 4... TV monitor, 15... Mount, 16... Lead, 17.
...Beretsu, 18...Table, 1
9...XY table, 20...Spindle,
21...Arm, 22...Wire, 23...
...Capillary, 24...Spindle arm, 25...
...Microscope, 26...Light, 27. ．．・...ITV camera for measurement, 28...TV monitor, 2
9... Screen, 30... Reticle, 31...
・・・・・・Surveillance ITV camera, 32・・・・Selector switch, 33・・・・Lever, 34……Y table full,
35... ...X direction parallel light east, 41...Sekiguchi, 42...mirror support arm, 43...reflector, 44...
...Y direction parallel light east. Younger brother P diagram Hair Z figure Younger brother 3 figure 4 Younger brother J figure

Claims (1)

[Claims] 1. A wire bonding apparatus that includes a table on which a work is placed, a capillary that holds a wire on the table, and a television camera that faces the table to observe the work, wherein the capillary and the television camera The capillary and the TV camera are installed on the same XY table so that they work together at a certain distance apart, and the TV camera is oriented substantially perpendicular to the workpiece placed on the table. Facing the table, confirming the predetermined position of the workpiece with the television camera, and using information on the pre-stored separation distance between the capillary and the television camera and information on the confirmed predetermined position of the workpiece. A wire bonding apparatus characterized in that the bonding position of the workpiece is determined, the position of the capillary is corrected in accordance with the determined bonding position, and bonding is performed to the workpiece.