JPH0695541B2 - Bonding surface height detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bonding surface height detection device.

[Conventional technology]

FIG. 4 is a partially sectional front view showing a conventional bonding surface height detecting device disclosed in, for example, Japanese Patent Publication No. 57-58054, in which (1) is a wire and (2) is a wire (1 ) Is inserted therethrough, (3) is an arm holder, (4) is a bonding arm that holds the capillary (2) at one end and is fixed to the arm holder (3) at the other end,
(5) is a vertical block that moves up and down in the direction of the arrow in the figure,
(6) is a rotary shaft that rotatably supports the arm holder (3) to the vertical movement block (5) via a bearing (not shown), and (7) is a lever fixed to the arm holder (3).
(8) is the first contact fixed to the lever (7), (1
Reference numeral 0) is a second contactor, which is fixed to the vertically movable block (5) through an insulating bush (9) corresponding to the first contactor (8). (11) is a spring that is provided between the up-down block (5) and the lever (7) and urges the first contactor counterclockwise, and (12) is fixed to the up-down block (5). A wire clamper for clamping the wire (1),
(13) is a sample mounting table, (14) is a lead frame guided and transferred to the sample mounting table (13), (15) is a lead frame (1
It is a pellet attached to 4). A voltage is applied to the first contactor (8) and the second contactor (19) by means not shown.

The following operation will be described. As is well known, in assembling a semiconductor integrated circuit or the like, wires are connected by a bonding device. That is, the capillary (2) having the wire (1) inserted therein is pressed against the pad of the pellet (15), which is the first bonding point, to bond, and then the capillary (2) is moved in the vertical and horizontal directions to move the wire (2). 1) Unwind and bond to the lead part of the lead frame (14), which is the second bonding point, raise the capillary (2) for a certain distance, clamp the wire (1) with the wire clamper (12), and then raise it further. The wire (1) is connected by repeating the operation of cutting the wire (1).

In the above operation, when the vertically moving block (5) descends, the capillaries (2) come into contact with the bonding surface of the pellet (15) or the lead frame (14). When the vertical movement block (5) further descends, the arm holder (3) rotates clockwise around the rotation shaft (6), and the first contactor (8).
Is separated from the second contact (10).

As a result, the contacts (8) and (10) become non-conductive, and the position where the capillaries (2) contact the bonding surface can be detected.

[Problems to be Solved by the Invention]

Since the conventional bonding surface height detection device is configured as described above, repeated stress due to ON and OFF acts on the first and second contactors (8) and (10), and the above contactors ( 8) The contact point of (10) deteriorates due to wear, point corrosion, fatigue peeling, etc., causing poor continuity and making it impossible to detect the height of the bonding surface, so relatively short-term maintenance was required. . Therefore, the above problems are solved by using a non-contact type position sensor such as a photoelectric sensor, a magnetic sensor, or a non-contact displacement type in place of the contact type position sensor such as the contacts (8) and (10). Can be easily considered, but in this case, the position sensor is sensitive to the noise due to the vibration due to the vertical movement of the vertical movement block (5) and the noise due to the external surge, and the bonding height is erroneously detected. Due to problems, a bonding surface height detector using a non-contact type position sensor has not been realized.

The present invention has been made to solve the above problems, and can detect the bonding surface height by using a non-contact type position sensor, and can detect the bonding surface height without erroneous detection due to noise. The purpose is to obtain the device.

[Means for Solving the Problems]

A bonding surface height detecting device according to the present invention holds a capillary for holding a wire and a capillary for pressing the bonding surface after the wire to be bonded is inserted and contacting the bonding surface, and bonding the wire to the bonding point. The bonding arm and the bonding arm are rotatably attached. Before the capillaries come into contact with the bonding surface, the bonding arm performs the same relative movement as the bonding arm, and after the capillaries come into contact with the bonding surface, the bonding arm becomes A swinging arm that moves to change its relative position, and a non-contact position attached to the bonding arm and the swinging arm to detect a change in the relative position between the bonding arm and the swinging arm. Sensor and above The storage device that stores the output value of the position sensor before the contact with the bonding surface is compared with the value stored in the storage device and the output value of the position sensor, and the absolute value of the difference between the two is greater than a certain value. And a comparison device which outputs a detection signal when

[Action]

In the bonding surface height detection device according to the present invention, a change in the relative position of the arm is detected by a non-contact type position sensor attached to the bonding arm and the swing arm, and the detected value and the value stored in the storage means are detected. When the absolute value of the difference between the two is compared with a certain value or more, a detection signal is output.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a partial sectional front view of an apparatus showing an embodiment of the present invention,
FIG. 2 is a block diagram of a detection circuit which constitutes a part of the apparatus of the above embodiment.

In the figure, (1) to (4), (6), (12) to (15)
Is the same as the above conventional device. (16) is a swing arm to which an arm holder (3) is attached via a rotary shaft (6) which is rotatably supported, (17) is a light shielding plate fixed to the arm holder (3), (18) ) Is a light emitting element fixed to the swing arm (16), and (19) is a light receiving element fixed to the swing arm (16) so as to face the light emitting element (18) with a gap, The light emitting element (18) and the light receiving element (19) form a photoelectric sensor (20). The light shielding plate (17) is positioned so as to be inserted between the light emitting element (18) and the light receiving element (19). Then, the light shielding plate (17) and the photoelectric sensor (20) constitute a non-contact type position sensor. The non-contact position sensor detects a change in output of the photoelectric sensor (20) according to a change in relative position between the light shield plate (17) and the photoelectric sensor (20) and detects the change in the bonding arm (4) and the swing arm. The change in the relative position of (16) is detected. (21) is a solenoid fixed to the swing arm (16), (22) is a lever fixed to the arm holder (3), and (23) is a plunger fixed to the lever (22). ) Is attracted to this. (24) is a detection circuit of the output of the photoelectric sensor (20), (25) is a sample hold circuit that temporarily stores the output of the photoelectric sensor (20) in accordance with a sample hold command, and (26) is a sample hold circuit (25). The output of the photoelectric sensor (20) temporarily stored in
It is a comparator circuit as a comparison means for comparing the output of (0) and outputting a detection signal when the absolute value of the difference exceeds a certain value.

Next, the operation will be described. In the bonding surface height detection device configured as described above, the solenoid (21) is energized when the carrier (2) descends, and the solenoid (21) attracts the plunger (23) to attract the solenoid (21). Press against an inner stopper (not shown) to hold it in that position. In this state, the bonding arm (4) and the swing arm (16) are united and rotate counterclockwise, and the photoelectric sensor (20) and the light shielding plate (17) are counterclockwise without relative displacement. Rotate to. At this time, a sample hold command is issued and the output voltage VO of the photoelectric sensor (20) is temporarily stored by the sample hold circuit (25). Then, before the capillaries (2) come into contact with the bonding surface, the energizing current to the solenoid (21) is reduced to reduce the attraction force of the solenoid (21). When the capillaries (2) come into contact with the bonding surface, the capillaries (2) stop at that position, but the swinging arm (16) further descends, moves for a certain distance and then stops, and the suction force of the solenoid (21) is applied. The corresponding force is applied to the capillaries (2). In response to the displacement of the swing arm (16), the photoelectric sensor (20) moves counterclockwise and changes its relative position with respect to the light shielding plate (17). Along with that, the output voltage V of the photoelectric sensor (20) changes as shown in FIG. The voltage VO temporarily stored in the sample hold circuit (25) and the output voltage V of the photoelectric sensor (20)
The comparator circuit (26) compares and and the detection signal is output when the absolute value of the difference between the two is greater than or equal to a preset value ΔV. This makes it possible to detect the position where the capillaries (2) are in contact with the bonding surface.

Although the photoelectric sensor and the light shielding plate are used for the non-contact type position sensor in the above embodiment, a hall element and a magnet, an overcurrent type or a capacitance type non-contact type potential type, etc. may be used.

〔The invention's effect〕

The bonding surface height detection device according to the present invention detects a change in the relative positions of the two arms by a non-contact type position sensor attached to the bonding arm and the swing arm, and the capillaries come into contact with the bonding surface. The output value of the position sensor when the bonding arm and the swinging arm before the movement are relatively the same is stored in the storage means, and the value stored in the storage means by the comparison means and the position sensor The output value is compared and the detection signal is output when the absolute value of the difference between the two exceeds a certain value, so noise due to vibration due to vertical movement of the vertical movement block and noise due to external surge are erroneously detected. Without doing so, the position where the above-mentioned capillaries contact the bonding surface can always be detected correctly.

Further, since the non-contact type position sensor is used, unlike the conventional device using the contact type position sensor, mechanical deterioration of the sensor due to contact does not occur and maintenance for a relatively short period of time is not required.

In addition, the output value of the non-contact type position sensor when the bonding arm and the swing arm are in the same motion before the contact of the capillaries with the bonding surface is stored in the storage means for each bonding operation, and it is used as a reference. Since the output change of the non-contact type position sensor is detected by the above, the stable and highly accurate bonding surface height is not affected by the characteristic change of the non-contact type position sensor due to temperature change or aging change. Can be detected.

[Brief description of drawings]

FIG. 1 is a partially sectional front view showing a bonding surface height detecting device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a detecting circuit constituting a part of the device of the above embodiment, and FIG. FIG. 4 is a waveform diagram of displacement of a swing arm tip and an input / output signal of a detection circuit, and FIG. 4 is a partial sectional front view showing a conventional bonding surface height detection device. In the figure, (1) is a wire, (2) is a capillary,
(3) is an arm holder, (4) is a bonding arm,
(6) is a rotating shaft, (16) is a swing arm, (17) is a photoelectric sensor, and (20) is a light shielding plate. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Claims: 1. A wire for inserting a wire to be bonded into contact with the bonding surface and thereafter pressing the bonding surface to bond the wire to a bonding point, a bonding arm for holding the capillary, and a bonding arm It is rotatably mounted and moves in the same manner as the bonding arm before the capillaries contact the bonding surface, and moves so as to change the relative position with the bonding arm after the capillaries contact the bonding surface. A rocking arm, a non-contact position sensor attached to the bonding arm and the rocking arm to detect a change in the relative position between the bonding arm and the rocking arm, and the capillaries on the bonding surface. Above before contact with A storage means for storing the output value of the position sensor and a comparison between the value stored in the storage means and the output value of the position sensor and issuing a detection signal when the absolute value of the difference between the two exceeds a certain value. And a bonding surface height detection device.