JPH11163030A - Method and device for wire bonding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize quality of bonded inner leads and improve availability of a wire bonding device, by electrically connecting the inner leads to pads of a semiconductor chip through metallic thin wires when bonding positions of the inner leads are within permitted limits. SOLUTION: After a lead frame mounted with a semiconductor chip 1 is fixed on a heat stage, bonding positions of pads 1a and inner leads 2a of the lead fame are recognized and the bonding positions of inner leads 2a to the pads 1a are corrected based on the recognized results. When it is discriminated that the bonding positions of the inner leads 2a are within permitted limits due to this correction, the inner leads 2a are electrically connected to the pads 1a of the semiconductor chip 1 through metallic thin wires 3. Therefore, the occurrence of insufficient press-fitting of the tips of the bonded inner leads 2a can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire bonding technique in a semiconductor manufacturing process, and more particularly to a wire bonding method and apparatus for stabilizing quality and improving the operation rate of the apparatus.

[0002]

2. Description of the Related Art The technology described below studies the present invention,
Upon completion, they were examined by the inventor, and the outline is as follows.

In wire bonding in a semiconductor manufacturing process, when a lead frame on which a semiconductor chip is mounted is held (fixed) on a heat stage of a wire bonding apparatus (hereinafter, referred to as a wire bonder), heat or frame holding is applied to the lead frame. Therefore, it is difficult to fix the inner lead so that the tip of the inner lead is always located at a fixed position.

For this reason, as a function of the wire bonder, a position correcting function of the bonding position for all the pins of the inner lead is provided.

Further, there is provided a limit function for automatically correcting the displacement of the bonding position within the range of a non-defective product and setting a certain limit so that the operation of the wire bonder is stopped when a defective product is detected. .

Here, various wire bonding apparatuses (wire bonders) are described in, for example, “Industrial Research Institute Co., Ltd., issued on November 25, 1994,
Test Apparatus Guidebook <1995 Edition>, Electronic Materials Separate Volume (1994 Separate Volume), pp. 110-117.

[0007]

However, in the wire bonder of the above-mentioned technology, since the bonding operation is set so as to minimize the product processing cycle, the position correction is performed while the lead frame itself is subjected to thermal stress. It is carried out.

[0008] Since the wire bonder is basically a processing machine, and all are configured to advance the processing process, it is possible to detect that the stress applied to the inner lead has not been completely released. However, it does not have the function of returning the machining process.

[0009] Furthermore, the function of the wire bonder is to function in the middle of the progress of the machining process, and to automatically correct these in the case of a setting defect or a change in the stress characteristics of the lead frame. is not.

Therefore, there is a problem that the position correcting function of the wire bonder is not sufficient as a function of correcting the position of the tip of the inner lead, which makes various changes.

Further, when setting the limit (threshold value) of the limit function in the wire bonder, there is a problem that it is not easy to optimize the threshold value.

An object of the present invention is to provide a wire bonding method and apparatus for stabilizing quality and improving the operation rate.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0014]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the wire bonding method of the present invention, the pads of the semiconductor chip and the inner leads are electrically connected. The lead frame on which the semiconductor chip is mounted is transported onto a heat stage and Pressing the lead frame to fix it, and after fixing the lead frame, performing the position recognition of the bonding position of each of the pad and the inner lead, and the bonding position of the inner lead and the pad. Performing a position correction of a bonding position between the inner lead and the pad based on a recognition result; determining whether a bonding position of the inner lead after the position correction is within an allowable range; and a result of the determination. When the inner lead is out of the allowable range, after a predetermined time elapses, Performing the position recognition and the position correction, and then performing the determination again, and as a result of performing the determination again, when the bonding position of the inner lead is within an allowable range, the pad of the semiconductor chip and Electrically connecting the inner lead with a thin metal wire.

Thus, it is possible to perform wire bonding after heating the lead frame to a saturated state.

That is, it is possible to prevent the lead frame from being fixed to the heat stage in the process of receiving the thermal stress and performing the position correcting operation of the lead frame in this state.

Therefore, even when the inner leads of the lead frame are deformed due to thermal stress, the position correcting operation can be performed according to the displacement of the inner leads.

As a result, the range of the allowable value of the displacement of each inner lead can be narrowed.
Insufficiency in pressure bonding at the tip of the inner lead in wire bonding can be reduced.

As a result, it is possible to stabilize the quality of the semiconductor device to which the wire bonding technique and the wire bonding are performed, and to facilitate the adjustment in the wire bonding apparatus.

Further, the wire bonding apparatus of the present invention includes a bonding section having a bonding head, a heat stage for supporting a lead frame on which a semiconductor chip is mounted, and a frame press for pressing the lead frame on the heat stage. Position recognition means for recognizing a bonding position of each of the inner leads of the lead frame supported by the heat stage and the semiconductor chip; and a method of recognizing each of the inner leads based on a recognition result of the bonding positions of the inner leads. Position correcting means for correcting a bonding position; determining means for determining whether or not the bonding position of the inner lead after the position correction is within an allowable range; and, as a result of the determination by the determining means, the inner lead outside the allowable range. When a predetermined time has passed when The position recognition and the position correction are performed, and then, the determination is performed again by the determination unit.As a result, when the bonding position of the inner lead is within an allowable range, the pad of the semiconductor chip and the inner lead are separated. And a main control unit for controlling electrical connection by thin metal wires.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view showing an example of an embodiment of the entire structure of the wire bonder of the present invention, FIG. 2 is an enlarged partial perspective view showing an example of the main structure of the wire bonder shown in FIG. 1, and FIG.
FIG. 4 is a block diagram showing an example of an embodiment of a structure of a control system of the wire bonder of the present invention. FIG. 4 is an enlarged partial plan view showing an example of a structure of a clamped state of a lead frame at the time of bonding in the wire bonder shown in FIG. 5 is A in FIG.
FIGS. 6A and 6B are diagrams illustrating an example of the structure of a portion, wherein FIG. 6A is an enlarged partial plan view, FIG. 6B is an enlarged partial cross-sectional view illustrating a BB cross section of FIG. FIG. 7 is an enlarged partial plan view showing an example of a structure of a lead frame in a clamped state, FIG. 7 is a flowchart showing an example of an embodiment of an operation procedure by a wire bonding apparatus of the present invention, and FIGS. It is a partial side view showing an example of an embodiment of an operation flow of a wire bonder based on a wire bonding method.

The wire bonder (wire bonding apparatus) of the present embodiment shown in FIG. 1 uses the bonding wires 3 (fine metal wires) shown in FIG. 6 as electrodes of the semiconductor chip 1 in the wire bonding step of the semiconductor manufacturing process. The pad 1a is electrically connected to the inner lead 2a.

First, the overall structure of the wire bonder shown in FIG. 1 will be described with reference to FIGS.
a bonding processing part 4 for electrically connecting the inner lead 2a to the inner lead 2a by a bonding wire 3, and a work fixing part for transporting the lead frame 2 on which the semiconductor chip 1 is mounted and fixing the lead frame 2 in the bonding processing part 4. 4c, a loader 5 for sending the lead frame 2 as a work toward the bonding section 4, and a lead frame 2 conveyed after wire bonding.
And an apparatus control unit 31 that controls each control unit of the apparatus main body 7.

Further, the apparatus body 7 includes a floppy disk drive 9 for reading initial data of the inner lead 2a for working conditions during bonding from a floppy disk, and an operation panel 1 having various operation buttons.
0 is provided.

The bonding processing in the bonding processing section 4 is performed by the work fixing section 4c and the XY table 1.
1f (see FIG. 2) bonding head 11
Are relatively moved in the X direction, the Y direction, or the Z direction.

The bonding section 4 includes a bonding head 11 for connecting the bonding wire 3.
And a microscope 12 for observing the state of the lead frame 2 and the like conveyed are mounted on the XY table 11f, and are provided on the upper part of the apparatus main body 7 when the position of the inner lead 2a is recognized and corrected. A monitor 13 as output means is provided.

Next, the detailed structure of the main part of the wire bonder according to the present embodiment will be described with reference to FIGS. 1 to 6. The heat stage 4a for supporting the lead frame 2 on which the semiconductor chip 1 is mounted, the lead frame Frame clamp 4b that presses 2 on heat stage 4a
(Frame holding), the bonding position of the inner lead 2a of the lead frame 2 supported on the heat stage 4a and the bonding position of each of the semiconductor chips 1, and a CCD (Charge Coupled Device) having a camera barrel 11h at the tip.
e) camera 11g (position recognition means) and inner lead 2a
Position correcting means 14 for correcting the bonding positions of the individual inner leads 2a based on the recognition result of the bonding positions of the above, and determining whether or not the bonding positions of all the inner leads 2a after the position correction are within the allowable range. Means 1
5 and the result of the determination by the determination means 15, when there is an inner lead 2a outside the allowable range, a predetermined time (for example, 2
After a lapse of about 3 seconds, the position recognition and the position correction are performed again, and then the determination is performed again by the determination unit 15. As a result, when the bonding positions of all the inner leads 2a are within the allowable range. Pad 1 of semiconductor chip 1
a and a main controller 16 for controlling the electrical connection between the inner lead 2a and the inner lead 2a by the bonding wire 3.

The position correcting means 14 and the judging means 15 in the wire bonder according to the present embodiment are, for example, circuits and the like.
In the following, a case where the position correction unit 14 and the determination unit 15 are incorporated in the main control unit 16 will be described.
Circuits provided independently of each other may be used.

In the wire bonder according to the present embodiment,
As a result of performing the above determination again, when there is an inner lead 2a outside the allowable range, after a predetermined time (for example, about 5 seconds) elapses, the main control unit 16 causes the frame clamp 4b to press the lead frame 2 down. Once released, the pressing of the lead frame 2 by the frame clamp 4b is performed again, and then the position recognition and the position correction are performed again, and the above determination is performed again. As a result, the bonding positions of all the inner leads 2a are changed. Control is performed to electrically connect the pad 1a of the semiconductor chip 1 and the inner lead 2a when the value is within the allowable range.

Here, referring to FIGS. 1 to 6, a detailed configuration of a main part of the wire bonder according to the present embodiment shown in FIG. 2, that is, the bonding processing unit 4 will be described.

FIG. 2 shows a mechanism for electrically connecting the semiconductor chip 1 mounted on the tab 2b supported by the tab suspension lead 2c (see FIG. 5) of the lead frame 2 to the inner lead 2a. Is a partially enlarged perspective view.

The bonding section 4 is divided into a system for transporting and fixing the lead frame 2 and a system for supporting the bonding head 11, and the system for transporting and fixing the lead frame 2 includes a heat block 4d for heating the heat stage 4a.
A frame clamp holder 4e for holding the frame clamp 4b, a frame clamp vertical movement block 4f for vertically moving the frame clamp 4b held by the frame clamp holder 4e, and a conveyance rail for guiding the conveyance of the lead frame 2. 4g flame shoot
And a feed claw 4h for pulling the lead frame 2 conveyed to a predetermined position (before the bonding position) into and out of the bonding position.

The bonding head 11 is supported by a bonding tool 11a such as a capillary (not shown), a wire clamper 11b as a member for gripping the bonding wire 3 for supplying and cutting the bonding wire 3, and a bonding wire 3 A torch electrode 11c that forms a ball by discharge energy at the tip of the head, a transducer 11d that converts electric energy into mechanical ultrasonic vibration, a head body 11e that is a body of the bonding head 11, and a head body 11e are mounted. XY table 11f.

The XY table 11f moves and stops the bonding head 11 and the CCD camera 11g on a horizontal plane at a controlled speed and direction.

FIG. 5 shows a structure in which the lead frame 2 is pressed on the heat stage 4a by the frame clamp 4b.

That is, as shown in FIG. 5B, the inner lead 2a and the tab 2b are placed on the heat stage 4a, and the inner lead 2a is pressed from above by the frame clamp 4b.

The positions of the inner leads 2a pressed by the frame clamps 4b are, for example,
It is a location about 1 mm inward from the tip of the inner lead 2a, and the holding allowance at that time is also about 1 mm.

However, the location at which the inner lead 2a is pressed and the amount of the press are not limited to the above numerical values but can be variously changed.

Thus, when the lead frame 2 is pressed on the heat stage 4a by the frame clamp 4b, as shown in FIG. 5A, the main surface of the semiconductor chip 1 mounted on the tab 2b is All the pads 1a and the tips (bonding portions) of all the inner leads 2a are exposed from the openings 4i of the frame clamp 4b.

Accordingly, in the opening 4i of the frame clamp 4b, the lead-side reference coordinates, the chip reference coordinates,
The position recognition and position correction of the coordinates of each inner lead 2a are performed by optical system image processing such as a CCD camera 11g provided in the wire bonder, and thereafter, final bonding coordinates are determined, where the torch electrode 11c and the bonding tool are determined. Wire bonding is automatically performed by 11a.

The lead frame 2 is made of, for example, an alloy of iron and nickel, or copper, and has a thickness of about 150 μm.

Further, the heating temperature of the lead frame 2 at the time of wire bonding is about 200 to 250 ° C.
Further, the lead frame 2 is fixed by the frame clamp 4b.
Is 5k when pressing on the heat stage 4a.
g.

Here, the configuration of the control system in the wire bonder shown in FIG. 3 will be described.
X including table 11f and members for driving the same
An XY table controller 18 for controlling the Y table unit 17 and a frame feeder controller 2 for controlling a frame feeder unit 19 which is a transport system of the lead frame 2.
0, bonding head 11 and bonding tool 1
1a, a bonding head control unit 22 for controlling a bonding head unit 21, a work supply / discharge control unit 24 for controlling a loader / unloader unit 23 including the loader 5 and the unloader 6, and a torch electrode 11
c, an external I / O control unit 27 for controlling an external device 25 such as an ultrasonic oscillator, a temperature controller, a floppy disk, and various sensors, and a peripheral device 26 such as a monitor 13;
An image processing control unit 29 for controlling the camera 11g, the amplifier 28, and the like, and a main control unit 16 for controlling each control unit are connected to the power unit 8.

Next, the wire bonding method according to the present embodiment will be described.

The wire bonding method of the present embodiment uses the wire bonder shown in FIGS.

First, step S1 shown in FIG. 7 is executed. The operation flow shown in FIG. 7 shows a bonding cycle 30 of one semiconductor chip 1.

In step S1, the frame clamp vertical movement block 4f and the frame clamp holder 4e are raised to predetermined positions as shown in FIG. 8A, and the semiconductor chip 1 is mounted as shown in FIG. From the loader 5 to the frame chute 4
g.

Thereafter, the lead frame 2 is conveyed to a position just before the bonding position by the guide of the frame chute 4g, from which the lead frame 2 is pulled into the bonding position, that is, a predetermined position on the heat stage 4a by the feed claw 4h.

Subsequently, as shown in FIG. 8B, the frame clamp vertical movement block 4f and the frame clamp holder 4e are lowered to predetermined positions,
b, the lead frame 2 is pressed and fixed on the heat stage 4a with a load of about 5 kg, and the lead frame 2 is positioned.

FIGS. 4 and 5 show a state in which the lead frame 2 is positioned and fixed on the heat stage 4a, that is, a final processing state in which the lead frame 2 is sandwiched and fixed by the heat stage 4a and the frame clamp 4b. It is shown in FIG.

As shown in FIG. 5, when the lead frame 2 is pressed onto the heat stage 4a by the frame clamp 4b, all the pads 1a on the main surface of the semiconductor chip 1 and the tips of all the inner leads 2a. (Bonding portion) is exposed at the opening 4i of the frame clamp 4b.

Further, when transporting the lead frame 2,
The lead frame 2 is preheated by the heat block 4d via the heat stage 4a.

Subsequently, after the position of the lead frame 2 is fixed (after the positioning), the CCD camera 11g is placed above the opening 4i of the frame clamp 4b as shown in FIG.
Thus, the position recognition of the bonding position of each of the pad 1a and the inner lead 2a of the semiconductor chip 1 and the position correction of the bonding position based on the position recognition are performed.

That is, in step S2 shown in FIG. 7, θ correction recognition (position recognition and position correction) of the semiconductor chip 1 and the inner lead 2a is executed.

This is because the CCD camera 11g captures image data of several predetermined parts, recognizes the coordinates of the actual positions of the pads 1a of the semiconductor chip 1 and the inner leads 2a (position recognition), and thereafter, Perform position correction based on position recognition.

Here, in the inner lead 2a, after acquiring one or two points of the correction reference of the inner lead 2a, all the individual inner leads 2a are taken in as image data (position recognition), and these image data are inputted in advance. The position is corrected based on the initial data (data in consideration of deformation) of each inner lead 2a.

Further, with respect to the pads 1a of the semiconductor chip 1, the shift amount of the semiconductor chip 1 is measured (position recognition) at two diagonal corners of the semiconductor chip 1, and each pad 1a is determined based on the shift amount. Is performed.

Thereafter, the coordinates of the bonding positions of all the inner leads 2a are confirmed by using the CCD camera 11g by the individual lead correction operation of step S3 shown in FIG.

Subsequently, in step S4, it is determined whether or not the bonding positions of all the inner leads 2a after the position correction are within the allowable range, assuming that the time is within a general processing cycle time.

Further, as a result of the judgment, when the inner lead 2a out of the allowable range exists, that is, when a correction error occurs in the individual read correction operation, after a predetermined time has elapsed, the position recognition and the position recognition are performed again. The position is corrected, and then the above determination is performed again (redetermination).

Here, in the present embodiment, the pad 1a of the semiconductor chip 1 and the inner lead 2a are connected by the bonding wire 3 when the bonding position of all the inner leads 2a is within the allowable range as a result of the re-determination. On the other hand, when the inner lead 2a is out of the allowable range as a result of the re-determination, the pressing of the lead frame 2 onto the heat stage 4a is performed after a lapse of a predetermined time. A case in which the lead frame 2 is released once, and thereafter, the pressing of the lead frame 2 to the heat stage 4a is performed again will be described.

Further, in the present embodiment, when the predetermined time (standby time) is set, the predetermined time (standby time before re-recognition) until the position recognition and the position correction are performed again; The case where the predetermined time (standby time before re-clamping) until the pressing of the lead frame 2 is released will be described separately.

For example, the waiting time before re-recognition is set to about 3 seconds, while the waiting time before re-clamping is set to about 5 seconds.

Here, the bonding operation after the result of the determination in step S4 shown in FIG. 7 will be described in detail.

That is, if the determination in step S4 is No (if any inner lead 2a outside the allowable range exists), the determination in step S5 indicates that the first inner lead 2a shown in FIG. The operation of the loop is executed (the upper limit number in step S5 is not limited to one, and may be a plurality of times other than one).

That is, when the determination in step S5 is the first time, the soft timer in step S6 is waited for about 3 seconds.

Further, after waiting for 3 seconds, the CCD camera 11g is placed again above the bonding position, and
The θ correction recognition in step S2 and the individual read correction operation in step S3 are performed, and then the re-determination in step S4 is performed.

By waiting for 3 seconds, the probability that the inner lead 2a will settle to its original position is increased, and it is possible to include a remedy for a change in the captured image due to the vibration of the CCD camera 11g.

Accordingly, the recognition pass rate can be improved.

As a result of the re-determination, when there is an inner lead 2a outside the allowable range, if n = 1 in the determination in step S5, the determination in step S7 is performed, and the determination in step S7 is performed. Is the second time, the operation of the second loop shown in FIG. 7 is executed. That is, the soft timer wait in step S6 is performed for about 5 seconds.

As described above, the waiting time before re-recognition (for example, 3 seconds) and the waiting time before re-clamping (for example, 5 seconds)
And by setting them separately and at different times,
The efficiency of the working time of the bonding operation can be improved.

Subsequently, after waiting for 5 seconds, the frame clamp vertical movement block 4f and the frame clamp holder 4e are raised by the operation of step S8 shown in FIG. The pressing of the lead frame 2 onto the lead frame 4a is released once in a heated state, and then the frame clamp vertical movement block 4f and the frame clamp holder 4e are lowered to press the lead frame 2 against the heat stage 4a again.

After the position of the lead frame 2 is fixed,
9 above the opening 4i of the frame clamp 4b.
As shown in (b), the CCD camera 11g is arranged, whereby the θ correction recognition in step S2 and the individual read correction operation in step S3 are performed again, and then the re-determination in step S4 is performed.

Here, the lead frame 2 is released once,
Thereafter, by re-clamping, the inner leads 2a that could not be stretched at the time of heating are released, and the stress is immediately released, so that the inner leads 2a can be brought closer to the initial state, and thus the inner leads 2a can be efficiently made. 2a can be calmed down.

As a result, the recognition pass rate can be further improved.

When releasing the clamp (pressing) of the lead frame 2, the release of the lead frame 2
In order to prevent the lead frame from moving, it is necessary to temporarily clamp the side surface of the lead frame 2 with the feed claw 4h shown in FIG. 2 before releasing.

Further, when the position of the inner lead 2a is recognized, the recognition speed is the same between the first and second times (the fetching of the image data of the optical system and the operation of each member). By adding a method of changing the data, the recognition process can be performed at a higher speed while maintaining the reliability of the data.

Thereafter, when it is determined in the re-determination that the bonding positions of all the inner leads 2a are acceptable, the bonding coordinates of each inner lead 2a and pad 1a at that time are determined as the final coordinates of the position to be bonded. .

In the determination in step S4 shown in FIG. 7, no matter how many times the determination is made, if it is determined that the bonding positions of all the inner leads 2a are acceptable, each inner lead 2a is determined to be acceptable. The bonding coordinate between the lead 2a and the pad 1a is set as the final coordinate of the position to be bonded.

If it is determined in step S7 shown in FIG. 7 that n is not equal to two (No, in other words, if an error occurs even in the operation of the second loop), an error is generated in step S9. Stops and executes the operator call unconditionally.

Subsequently, in the determination at step S4 shown in FIG. 7, the bonding positions of all the inner leads 2a passed, and as a result, the final coordinates of the bonding positions of all the inner leads 2a and the pads 1a were determined. At that time, thereafter, bonding is started in step S10.

That is, the wire bonding is started based on the final coordinates to be bonded between the pad 1a of the semiconductor chip 1 and the inner lead 2a obtained by the correction operation.

When performing wire bonding, first,
As shown in FIG. 10A, the CCD camera 11g is returned to the original position, and the transducer 11d and the bonding tool 11a are arranged above the bonding position.

Thereafter, each control unit is controlled by the main control unit 16 shown in FIG.
11d, bonding tool 1 shown in
Wire bonding is performed while controlling the 1a, the wire clamper 11b, and the like in each of the XYZ directions.

The heating temperature of the lead frame 2 during wire bonding is about 200 to 250 ° C.

FIG. 6 shows a state in which the pads 1a of the semiconductor chip 1 and the inner leads 2a are electrically connected by the bonding wires 3 by wire bonding.

After the bonding is completed, as shown in FIG. 10B, the transducer 11d and the bonding tool 11a are returned to their original positions, and the frame clamp vertical movement block 4f and the frame clamp holder 4 are moved.
e is raised to a predetermined position.

Thereafter, the lead frame 2 is fed by one pitch by the frame chute 4g, and the step S shown in FIG.
11 advances to the next step.

Thus, as shown in FIG. 7, the bonding cycle 30 for one semiconductor chip 1 is completed.

Thereafter, as shown in FIG. 4, the lead frame 2 on which the wire bonding has been completed is transported by the frame chute 4g, and is sequentially accommodated in the unloader 6.

By repeating these operations, automatic wire bonding is performed.

According to the wire bonding method and apparatus of the present embodiment, the following operational effects can be obtained.

That is, it is determined whether or not the bonding position of the inner lead 2a after the position correction (θ correction recognition) is within the allowable range. As a result of the determination, if the inner lead 2a is out of the allowable range, 3 After waiting for seconds, perform position recognition and position correction again, and then, as a result of performing the determination again,
By performing wire bonding when all the inner leads 2a are within the allowable range, the position recognition and the position correction can be performed after the lead frame 2 is heated to a saturated state, and then the determination can be performed. become.

That is, it is possible to prevent the lead frame 2 from being fixed to the heat stage 4a in the course of receiving the thermal stress and performing the position correcting operation of the lead frame 2 in this state.

When the inner lead 2a is out of the allowable range, the pressing of the lead frame 2 is released once, and then the lead frame 2 is pressed and fixed again, and the position recognition and the position correction are performed again. After that, when the above determination is made again, when the bonding positions of all the inner leads 2a are within the allowable range, the wire bonding is performed, so that the
Can be freely extended and the displacement of the inner lead 2a can be stored at a preset position.

Thus, even when the inner lead 2a of the lead frame 2 is deformed due to a thermal stress applied thereto, a position correcting operation can be performed according to the displacement of the inner lead 2a.

Therefore, it is possible to narrow the range of the allowable value of the displacement of the individual inner leads 2a, and thereby, the inner leads 2a in wire bonding can be reduced.
In this case, it is possible to reduce poor crimping at the tip end of a.

As a result, the quality of the wire bonding technique in the wire bonder can be stabilized, and furthermore, the semiconductor device (for example,
In addition to stabilizing the quality of a QFP (Quad Flat Package), it is possible to facilitate adjustment in a wire bonder (wire bonding apparatus).

In particular, it is effective for a wire bonding method using a multi-pin lead frame 2 and for stabilizing the quality of a semiconductor device manufactured using this method.

Further, since the range of the allowable value of the displacement of each inner lead 2a can be narrowed, the threshold value can be easily optimized.

Further, since the adjustment in the wire bonder can be facilitated, the input time of the bonding data when setting the bonding conditions can be shortened.

Further, since the adjustment in the wire bonder can be facilitated, the work of determining the type-specific data at the time of type change can be simplified, and as a result, the type change time can be shortened.

Further, since the position correcting operation can be performed according to the displacement of the inner lead 2a, the pass rate of the position recognition of the inner lead 2a can be improved, and as a result, the operation rate of the wire bonder can be improved. it can.

By applying the wire bonding method of the present embodiment, the stop rate of the wire bonder can be reduced from 0.3% to 0.02%, as an example.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the embodiments of the present invention, and does not depart from the gist of the invention. It is needless to say that various changes can be made.

For example, in the above-described embodiment, the second loop of the operation flow shown in FIG. 7 is deleted, and only the first loop is performed. At this time, the time of the soft timer standby in step S6 is set to about 5 seconds. One loop may be repeated a plurality of times.

The waiting time (3 seconds or 5 seconds) by the soft timer waiting described in the above embodiment is an example, and is not limited to this.

In the above-described embodiment, a case has been described in which the standby time before re-recognition and the standby time before re-clamping are separately set when setting the standby time by the soft timer standby. The waiting time before the re-recognition and the waiting time before the re-clamp may be set as the same time by the same timer.

Further, in the above embodiment, the first loop of the operation flow shown in FIG. 7 may be deleted and only the second loop may be provided.

That is, the determination is made in step S4. As a result, when the inner lead 2a is out of the allowable range, the pressing of the lead frame 2 on the heat stage 4a is released once, and then the heat stage 4a, the lead frame 2 is re-clamped. Further, the position recognition and the position correction (the θ correction recognition in step S2) are performed again, and subsequently, the determination is performed again. As a result, when the bonding positions of all the inner leads 2a are within the allowable range. This is to perform wire bonding.

In this case, substantially the same functions and effects as those of the above embodiment can be obtained.

The setting of the number of times n in the judgments of steps S5 and S7 shown in FIG.
Not limited to 1 or n = 2, various changes are possible.

Further, in the above embodiment, FIG.
In the first determination in step S4 shown in (4), a case has been described where the operation of the first loop is performed for all the inner leads 2a when at least one error has occurred. After a lapse of time (for example, about 3 seconds), the position recognition and the position correction or the re-clamping of the lead frame 2 are performed again only for the inner lead 2a outside the allowable range. The above-described determination may be performed again only for the lead 2a, and the wire bonding may be performed when all the inner leads 2a pass.

When an error occurs in the first determination in step S4 shown in FIG. 7, the θ correction recognition in step S2 may be performed before re-clamping.

Also, if an error occurs in the first determination in step S4 shown in FIG. 7 and the inner leads 2a on both sides of the inner lead 2a in which the error is found pass, the correction of the inner leads 2a on both sides is performed. The value may be used to perform wire bonding by relatively correcting the inner lead 2a in which the error has occurred.

Further, if an error occurs in the determination in step S4 shown in FIG. 7, vibration of the optical system may be considered as a cause of erroneous recognition.
The timer-related data provided between each operation step may be divided into a plurality of stages, and an operation mode for performing an automatic operation may be set.

[0119]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

(1). It is determined whether or not the bonding position of the inner lead after the position correction is within the allowable range. As a result of the determination, when the inner lead is out of the allowable range, after a predetermined time has elapsed, the position recognition, the position correction, and the determination are performed again. As a result, by performing wire bonding when all the inner leads are within the allowable range, it becomes possible to narrow the range of the allowable value of the displacement of the individual inner leads, and as a result, the wire Insufficiency in pressure bonding at the tip of the inner lead during bonding can be reduced. This makes it possible to stabilize the quality of the semiconductor device that has performed the wire bonding technique and the wire bonding.

(2). When the inner lead out of the allowable range exists, release the pressing of the lead frame once,
After that, press the lead frame again and fix it,
As a result of performing the position recognition, the position correction, and the determination again, when the bonding positions of all the inner leads are within the allowable range, the wire bonding is performed in the same manner as in the above (1). The quality of the bonded semiconductor device can be stabilized.

(3). According to the above (1) or (2),
Since it becomes possible to narrow the range of the permissible value of the displacement of each inner lead, it is possible to facilitate the adjustment in the wire bonding apparatus.

(4). Since the range of the permissible value of the displacement of each inner lead can be narrowed, the threshold value can be easily optimized.

(5). Since the adjustment in the wire bonding apparatus can be facilitated, the input time of the bonding data when setting the bonding conditions can be shortened.

(6). Since the adjustment in the wire bonding apparatus can be facilitated, it is possible to simplify the work of identifying the product-specific data at the time of product replacement, and as a result, it is possible to shorten the product replacement time.

(7). Since the position correction operation can be performed according to the displacement of the inner lead, the pass rate of the position recognition of the inner lead can be improved, and as a result, the operation rate of the wire bonding apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an embodiment of the entire structure of a wire bonder of the present invention.

FIG. 2 is an enlarged partial perspective view showing an example of a main structure of the wire bonder shown in FIG.

FIG. 3 is a block diagram showing an example of an embodiment of a structure of a control system of the wire bonder of the present invention.

FIG. 4 is an enlarged partial plan view showing an example of a structure of a clamped state of a lead frame at the time of bonding in the wire bonder shown in FIG. 1;

5 (a) and 5 (b) are views showing an example of the structure of the portion A in FIG. 4, wherein FIG. 5 (a) is an enlarged partial plan view thereof, and FIG. It is a partial sectional view.

6 is an enlarged partial plan view showing an example of a structure of a clamped state of a lead frame after bonding in the wire bonder shown in FIG. 1;

FIG. 7 is a flowchart showing an example of an embodiment of an operation procedure by the wire bonding apparatus of the present invention.

FIGS. 8A and 8B are partial side views showing one example of an embodiment of an operation flow of a wire bonder based on the wire bonding method of the present invention.

FIGS. 9A and 9B are partial side views showing an example of an embodiment of an operation flow of a wire bonder based on the wire bonding method of the present invention.

FIGS. 10A and 10B are partial side views showing an example of an embodiment of an operation flow of a wire bonder based on the wire bonding method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 1a Pad 2 Lead frame 2a Inner lead 2b Tab 2c Tab suspension lead 3 Bonding wire (thin metal wire) 4 Bonding processing part 4a Heat stage 4b Frame clamp (frame holding) 4c Work fixing part 4d Heat block 4e Frame clamp holder 4f Frame clamp vertical movement block 4g Frame chute 4h Feeding claw 4i Opening 5 Loader 6 Unloader 7 Device body 8 Power unit 9 Floppy disk drive 10 Operation panel 11 Bonding head 11a Bonding tool 11b Wire clamper 11c Torch electrode 11d Transducer 11e Head body 11f XY Table 11g CCD camera (position recognition means) 11h Camera barrel 12 Microscope 13 Monitor 14 Position Correction Means 15 Judgment Means 16 Main Control Unit 17 XY Table Unit 18 XY Table Control Unit 19 Frame Feeder Unit 20 Frame Feeder Control Unit 21 Bonding Head Unit 22 Bonding Head Control Unit 23 Loader / Unloader Unit 24 Work Supply / Discharge Control Unit Reference Signs List 25 external device 26 peripheral device 27 external I / O control unit 28 amplifier 29 image processing control unit 30 bonding cycle 31 device control unit

Claims (8)

[Claims] 1. A wire bonding method for electrically connecting a pad of a semiconductor chip and an inner lead, wherein the lead frame on which the semiconductor chip is mounted is transported onto a heat stage, and the lead frame is mounted on the heat stage. Pressing and fixing; and after fixing the lead frame, performing the position recognition of the bonding position of each of the pad and the inner lead. Based on the recognition result of the bonding position between the inner lead and the pad. Performing a position correction of a bonding position between the inner lead and the pad; and determining whether the bonding position of the inner lead after the position correction is within an allowable range. When the inner lead is present, the position recognition and the Performing the position correction, and then performing the determination again.As a result of performing the determination again, when the bonding position of the inner lead is within an allowable range, the pad and the inner lead of the semiconductor chip are separated. Electrically connecting with a thin metal wire. 2. The wire bonding method according to claim 1, wherein, as a result of the re-determination, when the inner lead is out of an allowable range, the lead frame is pressed onto the heat stage after a predetermined time has elapsed. Once released
When the pressing of the lead frame to the heat stage is performed again, and then the position recognition and the position correction are performed, and the determination is performed again.As a result, the bonding position of the inner lead is within the allowable range. And electrically connecting the pads of the semiconductor chip to the inner leads. 3. The wire bonding method according to claim 2, wherein, when the predetermined time is set, the predetermined time until the position recognition and the position correction are performed again, and pressing on the lead frame. Wherein the predetermined time until the attachment is released is set separately. 4. A wire bonding method for electrically connecting a pad of a semiconductor chip and an inner lead, wherein the lead frame on which the semiconductor chip is mounted is transported onto a heat stage, and the lead frame is mounted on the heat stage. Pressing and fixing; and after fixing the lead frame, performing the position recognition of the bonding position of each of the pad and the inner lead. Based on the recognition result of the bonding position between the inner lead and the pad. Performing a position correction of a bonding position between the inner lead and the pad; and determining whether the bonding position of the inner lead after the position correction is within an allowable range. When the inner lead exists, the lead frame to the heat stage Once you release the hold-down of the, then, again, fixed by pressing the lead frame to the heat stage,
Performing the position recognition and the position correction again, and then performing the determination again; and as a result of performing the determination again, when the bonding position of the inner lead is within an allowable range, the pad of the semiconductor chip. Electrically connecting the inner lead and the inner lead by a thin metal wire. 5. The wire bonding method according to claim 1, wherein the inner lead is out of the allowable range after a lapse of a predetermined time when the result of the determination indicates that the inner lead is out of the allowable range. The position recognition and the position correction or the pressing of the lead frame are performed again only for the inner lead, and thereafter, the determination is performed again only for the inner lead outside the allowable range. Bonding method. 6. A bonding section having a bonding head, a heat stage for supporting a lead frame on which a semiconductor chip is mounted, a frame holder for pressing the lead frame on the heat stage, and a frame supported by the heat stage. Position recognition means for recognizing the bonding position of each of the inner lead of the lead frame and the semiconductor chip; and position correction for correcting the bonding position of each of the inner leads based on the recognition result of the bonding position of the inner lead. Means for determining whether or not the bonding position of the inner lead after the position correction is within an allowable range; and, when the inner lead is out of the allowable range as a result of the determination by the determining means, a predetermined time After the elapse, the position recognition and the position correction are performed again. After that, as a result of performing the determination again by the determination unit, when the bonding position of the inner lead is within an allowable range, control for electrically connecting the pad of the semiconductor chip and the inner lead by a thin metal wire is performed. And a main controller for performing the operation. 7. The wire bonding apparatus according to claim 6, wherein as a result of the re-determination, when the inner lead is out of an allowable range, the main control unit presses the lead frame by the frame press. The attachment is released once, and after a lapse of a predetermined time, the lead frame is pressed again by the frame holding, and thereafter, the position recognition and the position correction are performed again, and the determination is performed again. A wire bonding apparatus for electrically connecting the pads of the semiconductor chip and the inner leads when a lead bonding position is within an allowable range. 8. A bonding section having a bonding head, a heat stage for supporting a lead frame on which a semiconductor chip is mounted, a frame press for pressing the lead frame on the heat stage, and a frame supported by the heat stage. Position recognition means for recognizing the bonding position of each of the inner lead of the lead frame and the semiconductor chip; and position correction for correcting the bonding position of each of the inner leads based on the recognition result of the bonding position of the inner lead. Means for determining whether the bonding position of the inner lead after the position correction is within an allowable range; and, as a result of the determination by the determining means, when the inner lead is out of the allowable range, the frame Pressing the lead frame by pressing Once released, then
Again, the lead frame is pressed and fixed to the heat stage by the frame retainer, the position recognition and the position correction are performed again, and then the determination is performed again by the determination unit. A wire bonding apparatus, comprising: a main control unit that performs control for electrically connecting a pad of the semiconductor chip and the inner lead with a thin metal wire when a bonding position is within an allowable range.