JPS6167927A - Wire-bonding device - Google Patents

Abstract

PURPOSE:To speed up the bonding operation and to favorably perform a bonding by applying the desired bonding load by a method wherein a capillary is provided being connected directly with a rotary motor. CONSTITUTION:One end of a capillary 1, wherein a bonding-wire is penetratingly inserted, is supported by a tool arm 2 and the other end of this arm 2 is directly connected with the rotating shaft 4 of a rotary motor 3. A tool lifter arm 6 is disposed in a case body 5 at the coupling part of this arm 2 and the revolution of the rotating shaft 4 is transmitted to the arm 2 through the arm 6. Moreover, the other end of the rotating shaft 4 is supported by the case body 5 through bearings 7 and a position detector 8 and a speed reducer 9 are provided adjacent to the motor 2. This case body 5 is placed on an X-Y table 10 and is made to shift to the position of the bonding pad 12 of a semiconductor chip 11. Furthermore, the capillary 1 is directly connected with the motor, an ultrasonic wave is made to generate from the arm 2 and the desired bonding load is applied to perform a bonding. By this method, the bonding operation is speeded up.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a wire bonding device, and particularly to a device capable of applying a desired bonding load.

[Technical background of the invention and its problems] Wire bonding devices are well known to those skilled in the art, and a bonding head is provided with a bonding tool having a capillary at one end, and the bonding tool is moved up and down by a drive source. . Generally, this drive source is currently in practical use, and has a configuration in which a motor is engaged with a cam or a link for reciprocating the rotational motion of the motor.

Therefore, it is necessary to incorporate a power transmission S mechanism such as a cam and a link into the bonding head together with the motor, which has the drawback of complicating the structure and increasing the size. - In addition, since cams and links are used, the power transmission is slow and high speed is desired.

In addition, the wear of the machine stock is significant, making it impossible to perform accurate hondaing.

In response to these demands, a linear motor was used as the drive bat = q.1, and a configuration in which a tool arm was provided directly connected to this linear motor was disclosed in Japanese Patent Publication No. 56-30735 and Japanese Patent Publication No. 56-30735.
It has been fully disclosed in No. 8-55664.

This idea was revised to meet the above request, but since linear motors have large inertia, it is difficult to control the desired load when applying a bonding load, which may damage the bonding pad or destroy the pellet. [Object of the Invention] This invention has been made in view of the above points, and provides a wire honding device capable of controlling whether or not to apply a desired honding load. It is something.

[Summary of the invention] An arm having a capillary at one end, a rotary servo motor provided to reciprocate the arm in one direction, and an arm reciprocated by the rotary servo motor. To obtain a wire bonding device comprising a means for detecting the position and speed, and a means for supplying a current to the rotary servo motor to pressurize the rotary servo motor after the capillary contacts the bonder 4 fu. It is something.

[Embodiments of the invention]

An embodiment of the inventive apparatus will be described with reference to FIG. rMk.

The other end of the tool arm (2), which supports the capillary mountain through which the bonding wire is inserted, is connected to
The tool arm (2) is directly connected to the rotating shaft (4) of the tool arm (3) so that the rotation by the rotating motor V3 is directly transmitted to the tool arm (2). Its cross-sectional view is shown in Figure 1 ((-)).

CI As you can see in the figure, the joint part of the tool arm (2) is the tool lifter arm (
6) The rotation of the rotating shaft (4) is connected to the tool arm (2) through the
It is configured to be transmitted to The rotating shaft (4) is supported by opposite side walls of the body (5) so as to be rotationally driven. Sliding properties are improved by a support mechanism that interposes a sepharing (7) at the end of the rotating shaft (4).

Further, the rotary motor (3) K is adjacent to the position detector (3).
) and speed reducer (9).

The position detector (3) is configured to detect the vertical position of the capillary (1) by detecting the rotational position of the rotary motor (3). The rotational position can be accurately detected by, for example, providing a slit or a striped pattern on the rotation shaft (4) and measuring it with a gold photo sensor in a non-contact manner.

11J, the capillary il+ hits the bonding surface.
In order to detect the time of concubinage, first rotate the rotary motor (3I) at a predetermined speed, and then
What is necessary is to detect that the rotary motor (3) stops rotating when the position detector (3) comes into contact with the bonding surface, and that a change occurs in the output signal of the position detector (3). The speed reducer (9) has the function of increasing the torque of the motor and increasing the resolution of the position detector (3) with respect to the displacement of the capillary fil. Motor (3)
If the torque is sufficiently large and the resolution of the position detector (3) is sufficiently high, it may be omitted.

The speed reducer (9) uses a planetary gear speed reducer, for example.
The rotation of the motor (4) is decelerated and the tool arm (2)
to communicate. The reduction ratio at this time is, for example, 50:l.

The speed reducer (9) and the rotary motor (3) constitute a rotary actuator uO, for example, a DC (direct current) length-bore motor.

For example, a piezoelectric vibrator (not shown) is directly connected to this tool arm (2) so as to generate ultrasonic vibrations during a bonding operation using the capillary peak.

HGT diagram of the pumping head configured in this way (5)
It is placed on the X-Y Cheelumi O as shown in FIG.

Used to move the capillary peak between bonding positions in a plane.

The X-Y table αO is driven by drive sources in the X-axis and Y-axis directions (
(not shown) is provided. For example, linear motors are directly connected to each. The above-mentioned bonding head performs bonding on the semiconductor chip αυ at the bonding position ■ and the next bonding position, for example, the lead frame α.
Bonding to the bonding position αΦ of J is performed.

In other words, the bonding head τ is moved to a pre-programmed bonding position by the X-Y table 00, and the vertical movement (up and down) is not shown in advance, for example, in the vertical direction shown in FIG. Bonding is performed by driving the rotation motor (3) in the direction.

When the tool arm (knife) is moved by the table αO near the bonding position and the capillary αV reaches the bonding surface (Fig. 2A), the rotary actuator αθ does not rotate any further, so the position detector (3) outputs As the change in the position signal suddenly decreases, the microcomputer in the control circuit detects that the tip of the gear pillar (1) has reached the bonding surface. Simultaneously with this prone position, the pressurizing operation begins. That is, the rotary actuator A predetermined current is controlled to flow through tIG, and a torque proportional to this current is applied to the capillary (1) via the rotating shaft (4).
) is applied to the tip of the metal wire, such as k'l* A4 Cu, to apply pressure to the bonding surface and to apply hydraulic pressure to the bonding surface of a wire such as k'l* A4 Cu.

During this layer stoppage, ultrasonic vibration is applied to the tool arm (2) as described above, and ultrasonic bonding is performed. After a predetermined period of time has elapsed, the tool arm (2) rises according to a predetermined speed curve, and is moved to the bonding position of the cab IJ-111'f and arrow by the X-Y table αO, and current is also applied to the DC servo motor. The next bonding is performed based on the speed curve shown in FIG.

An example of a series of drive systems using this DCf-motor is shown in FIG. That is, the rotating motor (II) shown in FIG.
The rotation based on the velocity curve of the capillary mountain due to K is detected by the position detector (a), and the detection output is supplied to the position-velocity converter (to) and the control circuit (to).

The output of the position-velocity converter (to) is fed back to the servo amplifier (7), and the pre-stored control signal of the output of the control circuit is also supplied to the servo amplifier (to) as a speed command signal with reference to the position signal r. After the amplification, the rotary actuator 118 is driven, and combeater control is executed while monitoring the rotational position of the rotary motor C]).

An example of a block diagram of this control device (2) is shown in FIG.

That is, the output signal of the position detector [present] is converted into a digital signal and is constantly counted by the position counter Uυ.

The CPU reads the contents of the position counter I at an appropriate timing and writes it to the current position counter of the memo IJ 143.

UPU v4a calculates the difference between the target position counter song stored in advance and the current position counter (b) and stores it in the deviation counter I4Q.

CP[J (rotation) further converts the speed command according to the contents of the deviation counter haze into an analog signal through the Ll/A f/verter @η and outputs it to the servo amplifier (7). This servo amplifier C9 rotates the motor θυ at a speed according to the speed command.

These memory contents are 1 at a certain timing (-cycle)
The first table of contents is updated, but the previous current position counter stores the current position of "j cycles" to be updated.

When the capillary descends at a constant speed from a point where it hits a boarding surface, for example, a semiconductor pellet, at a constant speed, the difference between the previous current position counter value and the current position counter value becomes approximately constant 1. If the capillary hits the pellet, the motor will no longer rotate, so the current position counter becomes 0. Therefore, by monitoring this difference, it is possible to detect when the capillary hits the pellet.

However, in reality, due to vibrations, etc., the previous current position counter value and current position counter value may vary and the difference may not be OK, so in reality, the previous current position - current position ≧
It is better to use the approximate time point r at which the detection point becomes 0 as the detection point. .

Since the tool arm is driven by being directly connected to the rotary motor in this way, a cam mechanism is not required and high-speed driving is possible.

Furthermore, since rotary motors have relatively small inertia, pressure control for bonding can be performed with higher density.
This has the effect of preventing destruction of the surface to be bonded due to pressurization.

In the above embodiment, a method was explained in which a microconbeater is used to determine whether the change in the signal of the position detector is within a predetermined value as a means of fully detecting whether the capillary is in contact with the bonding surface. If it is a detection means, for example, the seal lifter arm (
2) Fix the non-contact electrometer (c) to the cabinet 2IJ-1.
A device may be provided to detect minute vibrations when it contacts the bonding surface.

Furthermore, in the above embodiment, an example was explained in which a DC servo motor (817 &: A similar effect can be obtained by placing a gold film on the reducer coaxially with the actuator.

〔Effect of the invention〕

As explained above, according to the present invention, since the capillary is directly connected to the rotary motor, it is possible to increase the speed of the pounding operation, and it can also be constructed in a small size. Furthermore, since the rotary motor has a relatively small inertia, it has the effect of increasing the pressure on the bonding surface by 1flJ after detecting contact with the bonding surface.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining an embodiment of the device of the present invention (2
) Figure is a perspective view, Figure (G) is an explanatory diagram of the engagement state of the rotary actuator and tool arm in the prisoner figure, (Figure 0 is an explanatory diagram of the engagement state in the tool lifter arm in Figure 2. The figure is a speed curve diagram showing the displacement r of the capillary in the first section, and Figure 3 is a circuit configuration diagram showing the drive system of the rotary actuator in Figure 1. 1... Capillary, 2... Tool arm 3...Motor, 3...Motor, 6...
・Seal lifter arm, 8...Position detector. 9...Reducer agent Patent attorney Noriyuki Chika (and 1 other person) Figure 2 ``Time → Figure 3'34

Claims (3)

[Claims] (1) A tool arm having a capillary at one end, a rotary motor provided to reciprocate the tool arm in one direction, and means for detecting the position and speed of the arm reciprocated by the rotary motor. . A wire bonding apparatus comprising: means for supplying a constant current to the rotary motor to pressurize the rotary motor after the capillary contacts the bonding portion. (2) The means for providing a rotary motor so that the tool arm can reciprocate in one direction is a method in which the arm is supported by a tool lifter arm, and a rotary motor is provided to pivotally support and rotate the seal lifter arm. A wire bonding apparatus according to claim 1. (3) The wire bonding apparatus according to claim 1, further comprising means for supplying a constant current to a rotary motor to cause the capillary to vibrate ultrasonically during pressurization.