JP2818092B2 - Dam bar processing equipment for semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dam bar processing apparatus using a laser beam, which is suitable for removing a dam bar from a semiconductor device.

[0002]

2. Description of the Related Art A lead bar of a semiconductor device is provided with a dam bar for connecting a lead frame in order to prevent a resin after resin molding from flowing out on the lead frame. Then, after the resin molding, the dam bar is removed to make each lead frame electrically independent.
There are examples in which the lead frame is provided on two opposing sides of the four sides and examples in which the lead frame is provided on all four sides.
The type provided on all four sides is QFP
It is called a shape and has a high number of frames.

[0003] There are two methods of removing the dam bar: a pressing method in which the dam bars are removed collectively for each side, and a laser beam method in which one dam bar is removed one after another. Each has advantages and disadvantages,
The removal of the dam bar on the lead frame of the QFP type semiconductor device is more difficult than the removal by the mechanical press method because the pitch between the lead frames is extremely narrow.
The removal method using a laser beam is excellent.

A conventional example of dam bar removal by a laser beam is disclosed in Japanese Patent Application Laid-Open No. Hei 3-294077. This conventional example is an invention relating to a countermeasure against shrinkage distortion of a lead frame caused by the influence of resin during resin molding. The lead frame pitch should be in accordance with a predetermined standard, but the lead frame shrinks during resin molding, and the lead frame pitch deviates from the standard value. Therefore, a reference hole is provided in the lead frame, the reference hole is optically monitored, and if there is a deviation, control is performed to change the irradiation position of the laser beam by the deviation.

FIG. 2 shows an example of another conventional pulse laser processing machine.
Shown in The laser head 14, the processing head 12, the laser power supply 16, and the XY table 11, on which the work 10 to be processed is mounted and which can be moved in a horizontal plane (in the XY plane), the laser head 14 and the processing head 12 are vertically moved. The main controller 15 that automatically or manually controls the movement of the Z table 13 and the XY table 11 in the horizontal plane, the movement of the Z table 13 in the vertical direction, and the oscillation of the laser head 14 that moves in the (Z-axis direction). Prepare.

[0006] The laser power supply 16 is connected to the laser controller 2.
0, a stabilizing power supply 19, a capacitor unit 18 and a switch unit 17. The AC power supplied from the stabilizing power source 19 is changed to DC according to the voltage value instructed by the laser controller 20, and supplied to the capacitor unit 18. ,
The charge of the capacitor unit 18 is supplied to the switch unit 17. The switch unit 17 operates in accordance with a trigger signal for instructing a pulse width and a pulse frequency from the laser controller 20, and the laser head 14 oscillates in a pulsed manner from the laser head 14 according to the trigger signal.

[0007] The laser head 14 has a built-in beam shutter (not shown), and whether the pulsed laser beam is transmitted to the processing head 12 by opening and closing (O).
N / OFF). That is, the beam shutter is opened when the work 10 is processed (dam bar removal), and the beam shutter is closed when the work 10 is not processed. The operation time of this beam shutter is 100-300
The control is performed by the laser controller 20 described above, but may be performed by the main controller 15 via the laser controller.

FIGS. 3A and 3B are explanatory views of a QFP type semiconductor device and dam bar processing. The QFP type refers to an IC package having a configuration in which a lead frame 22 is led outward from four sides Q1 to Q4 of a semiconductor device 21.
Usually, two opposing sides of the four sides (for example, Q1 and Q
The lead frame is derived from 3). However, in a high-density semiconductor device, the number of lead frames also increases, so that the lead frame is formed on all four sides. Also, the pitch interval between the lead frames on each side is extremely short. A dam bar 23 is formed on the lead frame 22 on each side so as to connect it. When the semiconductor device 21 is molded with a resin, the dam bar 23 serves as a dam to prevent the resin from flowing out to the entire lead frame. After the molding, the dam bar 23 is removed. It is necessary to make the lead frame electrically independent. There are a mechanical removal method using a punch and a laser removal method for removing the dam bar 23. In FIG. 2, the laser removal method is employed.

FIG. 3B is an enlarged view of the lead frame and the dam bar. After the removal of the dam bar including the point A is completed, the control sequence for removing the dam bar including the point B is as follows. (1) The table 11 is moved so that the laser irradiation position on the work 10 changes from A to B. (2) When the position of B is reached, the XY table 11 is stopped. (3) Open the beam shutter. (4) Irradiate a pulse laser. (5) Close the beam shutter. The above operations (1) to (5) are repeated as one sequence for each dam bar position, and the dam bars are removed one after another. At this time, (1) to (5) are changed to the main controller 1
The sequence control can be performed by programming the memory in the memory 5 in advance.

[0010]

Problems to be Solved by the Invention
No. 7 is concerned with shrinkage of the lead frame of the entire semiconductor device. Therefore, the position fluctuation of the entire semiconductor device is monitored based on the displacement of the reference hole. However, in addition to shrinkage due to the resin mold, various positional deviations occur due to mounting errors of the semiconductor device on the processing table, fluctuations in pitch between lead frames during lead frame molding, and the like. In particular, in a QFP type semiconductor device for high-density framing, since the number of lead frames on one side is large and the pitch interval is narrow, it is difficult to monitor only the entirety. There must be. In many cases, the displacement of the lead frame is caused by the fluctuation of the pitch width. That is, there is a problem that the pitch width is wide and narrow. Therefore, in order to correct the displacement of the lead frame and remove only the dam bar, it is necessary to consider not only the correction of the individual positions of the lead frame but also the processing method corresponding to the wide and narrow pitch width.

Further, the conventional example shown in FIG. 2 has the following problems. Each dam bar has a width of 0.1 ~
Since the thickness is about 0.3 mm and the thickness is about 0.15 mm, this cutting can be sufficiently performed by one pulse of the pulse laser beam.
Therefore, the time required for the actual processing corresponds to the time of the pulse width of the pulse laser light, and is about 0.1 msec. However, in the processing procedures (1) to (5), the operation time of the beam shutter is 100 to 300 ms.
It takes about 1 second to cut one dam bar according to ec and the moving time of the table, and when the number of cut dam bars and the number of manufactured IC packages are taken into consideration, too much processing time is required.

In general, the pitch of the pins is often the same. However, the dam bar deforms due to manufacturing errors of the lead frame, distortion due to the temperature history when molding with resin, external force due to handling, etc. May not always be at the same pitch at the time of cutting. The dam bar cutting method described above is a method of registering the dam bar cutting position in advance in the main controller 15 as a program. However, this method cannot cope with the fact that the pins are not at the same pitch. In the worst case where errors and deformations accumulate and the errors increase, there is a possibility that the pins of the lead frame that should be left may be damaged.

An object of the present invention is to provide a semiconductor device capable of reliably removing a dam bar at an equal distance from both the start end and the end end of the dam bar even if the pitch and width of the dam bar are not uniform. And a dam bar processing apparatus.

[0014]

According to the present invention, a semiconductor device is reciprocated, and a laser beam from a processing head is irradiated on a dam bar connecting a lead frame of the semiconductor device in each of a forward path and a return path. Is removed (claim 1).

Further, according to the present invention, a semiconductor device is reciprocated,
In each of the forward path and the return path, the dam bar connecting the lead frame of the semiconductor device is irradiated with a laser beam from the processing head to remove the dam bar, and in the forward path, a predetermined distance from the start end of the dam bar along the forward path. The dam bar is removed by irradiating the laser beam around the position of the distance of the center, and the dam bar is removed by irradiating the laser beam around the position of the predetermined distance from the starting end of the dam bar along the backward direction in the return path ( Claim 2).

Further, the present invention relates to the appearance of a dam bar at the light receiving position of the reflected light (or transmitted light) of the illuminating light radiated to the periphery including the laser beam irradiating position of the processing head and along the moving direction of the forward path or the backward path. A photo sensor having a spot-shaped sensitive area is provided at a position where the situation can be monitored, and the photo sensor detects a dam bar start end along the moving direction of the forward or backward movement of the dam bar, and detects the predetermined end from the detected start end. The laser beam is radiated around the position of the distance (claim 3).

[0017]

According to the present invention, dam bar processing of a semiconductor device is performed by reciprocating the semiconductor device and dam bar processing is performed on the outward path and the return path. This allows
Even if the dam bar pitch and the dam bar width are not aligned, the dam bar can be removed neatly from a position at a predetermined distance from both ends of the dam bar.

Further, according to the present invention, both end portions of the dam bar are detected by the photo sensor, and a laser beam is irradiated around a position at a predetermined distance from the detected both end portions. This allows removal of the dam bar while continuously reciprocating without relying on a pre-programmed sequence.

[0019]

FIG. 4 is different from FIG.
FIG. 4 which is characterized in that a value signal generation circuit 25 is newly provided is shown in FIG.
No. 114). Photo sensor 2
4 is used for monitoring the position of the dam bar, and the binary signal generation circuit 25 detects the appearance of the dam bar from the output of the sensor 24 by 2.
Value signal. The binary signal is sent to controllers 15 and 20 and used for laser irradiation timing control. In the prior application shown in FIG. 4, when removing a series of dam bars on one side, the workpiece is continuously moved without stopping, and the dam bar can be removed at the center position of each dam bar in the process of continuously moving. It is. In FIG. 2, the work is stopped for each dam bar and the open / close shutter is opened and closed. However, in the prior application shown in FIG. 4, none of these operations is performed, and the work is continuously moving and the shutter is opened. It remains. In the prior application shown in FIG. 4, the photo sensor 24 detects the appearance position of each dam bar (the leading edge position of each dam bar) due to the movement of the work, and emits a laser beam from the leading edge position at the center position of the dam bar. The laser beam is generated at this timing. With one laser beam, the center of one dam bar can be removed instantaneously,
The time required for the removal is a value that can be ignored compared to the unit moving time based on the moving speed. Therefore, even if the work is continuously moved, the dam bar is processed at a high speed, and does not hinder the continuous movement of the work. Then, even if the leading edge positions of the dam bar are not aligned, the leading edge position itself can be detected by the photo sensor 24, so that the center position of the dam bar can be reliably removed against the mismatch.

A specific example of the photosensor 24 is shown in FIG. 1, and the configuration of this photosensor is an extension of the photosensor having the configuration shown in FIGS. In the following, examples of the photosensor of FIGS. 6 and 7 will be described.
FIG. 1 shows an embodiment of the present invention and FIG.
There will be a description using the following. Note that there is an example of transmitted light instead of reflected light. In this case, the photo sensor 24 is provided on the transmission side.

FIG. 5 shows an optical system including the photo sensor 24. The processing head 12 has a dichroic mirror 27,
A bending mirror 28, a condenser lens 29, and an imaging mirror 26 are incorporated in advance. The laser beam from the laser head 14 is applied to the work 1 via the bending mirror 28.
Remove the dam bar on 0. On the other hand, the illumination light source 26
Is applied to the lead frame via the dichroic mirror 27, the bending mirror 28, and the condenser lens 29. The reflected light enters the imaging lens 26 via the same optical path, enters the photosensor 24 provided on the fixing member 100 via the opening 100A, and forms an image on the lead frame. Note that an assist gas supply system during laser processing is omitted.

FIG. 6 is a diagram for explaining the size of the sensitive area of the photo sensor 24. As shown in FIG. Arrows indicate the direction of table movement (x direction). The magnitude of the illumination light from the imaging lens 26 is a circular portion 30 in the figure. This circular part 30
A portion of the space portions (slit portions) 23A and 23B existing on both sides in the direction orthogonal to the moving direction with the two dam bars 23 and the lead frames 22A on both sides in the direction along the moving direction,
22B, and one dam bar 23
Is large enough to show the situation around it.
This field of view also changes as the table 11 moves. On the other hand, the sensitive area of the photosensor 24 has a size as shown by a minute hatched circular portion, and this size is a spot value sufficiently smaller than the size of the dam bar 23. By setting the sensitive area of this small diameter, not only the appearance of the dam bar 23 due to the movement of the table 11 but also the appearance of the left and right lead frames 22A and 22B of the dam bar along the moving direction of the table 11 are finely tracked. Can be monitored. The movement of the table 11 causes the photosensor 24 to make a locus indicated by a dotted line in FIG. 7, and the sensing target area of the photosensor 24 changes one after another. Know the position.

The tracking of the dam bar by the photo sensor 24 and the timing of cutting the dam bar will be described below. First I
The work 10 which is the lead frame of the C is moved to the XY table 1
For example, when the target 1 is moved at a constant speed in the positive direction of the X-axis, the image formed by the reflected light from the workpiece 10 formed on the target shown in FIG. 6 also moves in the positive direction of the X-axis. However, since the photo sensor 24 is fixed, the change in the detection signal, which is the output from the photo sensor 24, is high in the space 23B (slit) as shown in FIG. ) 22
A and 22B have low outputs. However, the detection signal here is assumed to have a high output when the light is strong and a low output when the light is weak. If the space portion 23B and the lead frame portions 22A, 22B of the work 10 are arranged at a constant pitch as shown in FIG. 7, the XY table 11 moves at a constant speed, and the detection signal is detected as a waveform having a constant period. Is done. On the other hand, when the space portion 23B of the work 10 and the lead frames 22A and 22B are not arranged at the same pitch, the detection signal is detected as a waveform having a time change proportional to the pitch change.

Next, FIG. 8 shows a binarized signal generation circuit 25, FIG. 9 shows a portion relating to the main body of the laser controller 20, and FIG. 10 shows a waveform diagram of each portion thereof. FIG.
The binary signal generation circuit 25 includes a comparator 251 and a delay circuit 252. The comparator 251 compares the magnitude of the output of the photosensor 25 with the threshold value TH. If it is, "0" is output. The threshold value TH is selected so that the leading edge of the dam bar has a rising edge of "1" and the rear end position has a rising edge of "1". The delay circuit 252 delays the binarized detection signal by a delay time t ₁ instructed by the main controller 15 and sends it to the laser controller 20 as a first rectangular wave signal P. This delay time t
The meaning of ₁ will be described later.

The laser controller 20 shown in FIG. 9 includes an internal generator 201, a gate circuit 202, and a trigger circuit 203.
Consisting of The gate circuit 202 is a rectangular wave signal generation circuit 25.
The first rectangular wave signal P from the internal generator 201 and the second rectangular wave signal G from the internal
The signal P is output when TP = 1 when using the output of the photosensor 24 of this embodiment, and TP when the output of the photosensor is not used.
= 0, the signal G is output. The trigger circuit 203 generates a trigger signal corresponding to the rise of the rectangular wave signal input from the gate circuit 202, inputs the trigger signal to the switch unit 17, and oscillates a pulse laser beam according to the trigger signal.

FIG. 10 shows the waveform of each part of the circuits of FIGS. 8 and 9. The oscillation of the pulsed laser light of FIG. 9 is actually a pulse having a certain width. 10 is very small in comparison with the width of the signal of FIG.

The output pulse G of the internal generator 201 output at TP = 0 is a pulse having a fixed period,
Laser oscillation is performed according to the fixed period. In the laser oscillation by the pulse G, the laser is emitted to the processing head or stopped using the opening and closing of the opening and closing shutter described above. Therefore, in this embodiment in which the photo sensor 24 is provided, the output pulse G is not used.

Next, the delay time t ₁ of the delay circuit 252 will be described. The delay time t ₁ is a time for setting the irradiation position of the laser at the center position of the dam bar as shown in FIG. The moving speed of the workpiece is represented by v, the width of the dam bar is represented by w, and various delay times (gompator 25
1 is the binarization processing time, the processing time by the laser controller 20, the delay time of the switch unit 17, and the total delay time until the pulse laser light oscillation) is t ₂ , and the dam bar width w is the moving speed. Assuming that the moving time is t, the following relational expression is required in order for the processing position to be the center position of the dam bar.

[0029]

T = w / v = 2 (t ₁ + t ₂ ) From this, t ₁ is obtained as follows:

[Number 2] becomes _{t 1 = 2 (w / v} ) -t 2. That is, the oscillation of the pulsed laser light is
The detection is performed (t / 2) hours after the detection at 4, and this position is the dam bar center position. Here, t ₂ , w, and v are
It is input in the main controller 15 in advance.

A description will be given of a processing procedure for cutting a dam bar of an IC having a dam bar on one side by the above operation. First, the trajectory passing through the dam bar, the moving speed of the workpiece 10, i.e., keep the input moving velocity v of the XY table 11, the width w of the slit portion 23B of the workpiece 10, and the delay time t ₂ to the main controller 15. or,
Here, since the dam bar is cut, the first rectangular wave signal P is input to the trigger signal 203 in the gate circuit 202 with the movement of the XY table 11, that is, the control signal TP = 1 is input to the gate circuit 202. The program is input to the main controller 15 as described above. When this program is run, the table 11 moves at a constant speed, and a pulse laser beam oscillates at a period determined by the pitch of the slit 23B and the moving speed v of the table 11,
The irradiation is performed at the center of the slit portion 23B, and the dam bar is cut.

For example, in the case where the laser oscillator used here is a pulse-excitation type YAG laser, if the maximum oscillation frequency is about 300 Hz, the cycle is 3.
Although it is about 3 ms, if a period determined by the pitch of the slit portion 3 and the moving speed v of the table 21 is set to this value, the time per dam bar cutting is 3.
3 msec, which can be dramatically reduced as compared with the related art.
If the pins are not equally spaced, that is, if the pitch between the web portion and the slit portion is not constant, the pulsed laser light should be oscillated at a position separated from the end portion of the web portion by a predetermined distance. If so, the dam bar can be cut in the same manner. Further, even when the pins are not equally spaced, the dam bar can be cut at a position apart from the end of the web portion by a predetermined distance. This position and the intermediate position in the case of the above equal intervals are collectively referred to as a reference intermediate position.

FIG. 11 is a sectional view showing an example of an I having dam bars 2 on four sides.
Fig. 1 for efficient cutting of C package dam bar
As shown in FIG. 2, four photo sensors 24A to 24D are arranged at fixed positions indicated by w1 to w4 in the drawing. Then, the binarized signal generation circuit 25 further selects a detection signal corresponding to the moving direction of the work 1 among the detection signals from the photosensors at the positions w1 to w4, and a first signal based on the selected detection signal.
Is input to the control means, and subsequent processing is performed in the same manner as in the above-described embodiment. First, when cutting the dam bar 23 in the portion of Q3, the detection signal from the photosensor 24A at the position w1 is selected in the binarized signal generation circuit as shown in FIG. 12A, and cutting is sequentially performed in the X-axis direction. . Next, when cutting the dam bar 23 in the portion of Q2, as shown in FIG.
The detection signal from B is selected in the binarized signal generation circuit, and cutting is sequentially performed in the positive direction of the Y axis. Hereinafter, similarly, the portion of Q1 is sequentially cut in the negative direction of the X axis,
Is sequentially cut in the negative direction of the Y axis. In this manner, all the dam bars 23 on the four sides can be continuously cut.

When the dam bar is cut using the above-described photosensor, if the pitch of the dam bar and the width of the dam bar are large and small and not uniform, the cutting state of the dam bar becomes uneven. This is shown in FIG. FIG. 13 is a top view of three adjacent dam bars 23 and a lead frame 24 interposed therebetween. Here, the dam bar pitch width P and the dam bar width W of the first dam bar shown on the left side and the second dam bar shown in the middle are as follows. First dam bar P = P ₀ (reference size) W = W ₀ (reference size) Second dam bar P = P ₀ ′ (P ₀ ′> P ₀ ) W = W ₀ ′ (W ₀ '> W ₀ )

Therefore, assuming that the semiconductor device moves in the direction of the arrow (forward path) in FIG. 13, according to the prior application, the first dam bar and the second dam bar respectively have (t / t) from the leading edge of the dam bar. 2) The dam bar is cut at the position a after the moving time. As a result, in the first dam bar, the left and right remaining portions of the dam bar after cutting are equal, and the width in the left and right direction itself is an expected small value, which is not a problem.
However, in the second dam bar, a remnant A on the right side is significantly left as shown in FIG. The presence of the remaining portion A on the right side deteriorates the quality and adversely affects the subsequent process. For example, in the post-process, there is a lead frame bending process,
During this bending, the remaining part of the cut will be bent,
The bending becomes insufficient, which causes an error in the plane of the lead frame. In addition, although there is a step of soldering to the lead frame, extra solder may be added to the remaining portion of the cut, which may cause a short circuit between the lead frames.

There is another problem. FIG. 13 shows an example in which the width D that can be cut by one laser beam with respect to the width W _{0 of} the dam bar is not so small (ie, W ₀ ≒ 2D). However, as shown in FIG. 14 (a), (b) , ' if is sufficiently small (W ₀ "D' when it cut by one shot of the laser beam with respect to the width W ₀ of the dam bar width D) also ( An example in which one laser beam is narrowed down by a beam, or an example in which a dam bar width is relatively large. In such a case, in the manner of the prior application, as shown in FIG. 14 (a), the position of the distance L ₁ from the starting edge of the dam bar by giving a delay time, or 1
As shown in FIG. 4 (b), the cut point is located at the center of the dam bar,
Give a delay time so that FIG.
In (a), the rest of the right dam bar is large, and FIG.
In (b), dam bar remnants are generated on the left and right sides which cannot be ignored.

Thus, in the case of W ₀ >> D ',
The remaining portion of the dam bar becomes large, leaving quality deterioration and problems in subsequent processes.

Therefore, in the present invention, not only the forward movement but also the backward movement is performed, and both the forward movement and the backward movement are given a delay time so that the dam bar is cut off.

FIG. 1 is a diagram showing the principle of operation of the present invention.
FIG. 14 is a diagram corresponding to FIG. 13. First, while the forward movement of the table equipped with the semiconductor device continuously, giving reference dam bar width W ₀ as data, to remove the dam bar around the position of the distance L from the left end portion of the dam bar.
In the dam bar having a width of the reference dam bar width W ₀ is the position of the distance L, and the central position of the dam bar. A series of dam bars are removed one after another by this forward movement, and then a return movement is performed. In this backward movement, it provides a reference dam bar width W ₀ as data. Photo sensor 2
4A detects the end of the dam bar, but unlike the forward movement, it detects the right end of the dam bar. And
The dam bar is removed around the position b at a distance L from the right end. In the second dam bar in the middle, the hatched portion B is removed, and in the first dam bar on the left side, the dam bar removed in the forward movement is removed again due to the reference dam bar width (actually, it is already removed in the forward movement). Just irradiate the laser beam).

By performing the outward and return trips as described above, even a wide dam bar can be removed at a position at a predetermined distance L from both ends. Further, even if the dam bar is narrower than the reference width W ₀ , there is no problem as long as the dam bar has a width larger than the width that can be removed by one laser beam.

FIG. 15 is a diagram showing the operation principle when the dam bar width is relatively sufficiently larger than the width that can be removed by a single laser beam as in the example of FIG. In the forward movement, performs dam bars removed at a distance L ₁ from the left end portion of the dam bar. The backward movement, performs dam bars removed at a distance L ₁ from right side end portion of the dam bar. In any case, the photo sensors 24 and 24A are used. According to this figure, the central portion A 'can be removed together. Distance selection of L ₁ are different, chosen such that the width of the dam bar balance being a small value.

In order to realize the dam bar removal sequence by reciprocating movement as shown in FIGS.
1 may be moved according to a speed pattern as shown in FIG. FIG. 16A shows an example of a speed pattern, in which speed patterns having different polarities are provided for the forward path and the return path. First, the apparatus moves forward, and laser pulses as shown in FIG. Then, the dam bar is removed, and furthermore, the outward movement is performed, and laser pulses as shown in FIG. 16B are successively given in the constant speed section to remove the dam bar. Both laser pulses, it is needless to say that the position of the distance L ₁ is one obtained by giving a delay time such that removal center.

In the above embodiment, it is assumed that the laser beam irradiation timing for the forward path and the return path is determined by the photo sensor 24A. However, the laser beam irradiation timing for the forward path and the return path is determined in other ways. Examples are possible. For example, it is also possible to remove the dam bar between the forward path and the return path by using the sequence of (1) to (5) relating to FIG.

Although the laser oscillation is pulsed, continuous oscillation may be used. In such continuous oscillation, it is determined whether or not to irradiate the processing head with the laser beam using the open / close shutter.

Further, when the position of the dam bar is displaced in the direction perpendicular to the moving direction, the laser beam may be irradiated while correcting such displacement in the perpendicular direction.

[0045]

According to the present invention, when the dam bar pitch and the dam bar width are not uniform or when the dam bar width is too wide compared to the laser beam removal width, a predetermined distance is set from both ends of the dam bar. It is now possible to remove the dam bar while leaving only a distance.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of dam bar processing by reciprocating movement according to the present invention.

FIG. 2 is a configuration diagram of a conventional dam bar processing apparatus using a laser beam.

FIG. 3 is a diagram showing a top view of a QFP type semiconductor device and an example of dam bar processing.

FIG. 4 is an embodiment view of the dam bar processing apparatus of the present invention.

FIG. 5 is an embodiment diagram of an optical system incorporating the photosensor of the present invention.

FIG. 6 is an installation example diagram of a photosensor.

FIG. 7 is a detection waveform diagram of the photosensor of FIG. 6;

FIG. 8 is a diagram showing an embodiment of the binarization circuit 25 of the present invention.

FIG. 9 is a view showing an embodiment of the laser controller 20 of the present invention.

FIG. 10 is a waveform diagram of each part of the circuits of FIGS. 8 and 9;

FIG. 11 is a top view of the QFP type semiconductor device.

FIG. 12 is another layout example of the photosensor.

FIG. 13 is an example diagram of dam bar processing when there is a difference in dam bar pitch and dam bar width.

FIG. 14 is an example diagram of dam bar processing when the dam bar width is larger than the removal width by a laser beam.

FIG. 15 is an example diagram of dam bar processing in the present invention.

FIG. 16 is a diagram showing a reciprocating movement sequence.

[Explanation of symbols]

 Reference Signs List 10 work (semiconductor device) 11 XY table 12 processing head 13 Z table 14 laser head 15 main controller 16 laser power supply 24 photo sensor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeyuki Sakurai 650 Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Works (58) Fields surveyed (Int. Cl. ⁶ , DB name) H01L 23/50 B23K 26/00

Claims (3)

(57) [Claims] 1. A dam bar for a semiconductor device in which a semiconductor device is reciprocated, and a dam bar connecting a lead frame of the semiconductor device is irradiated with a laser beam from a processing head to remove the dam bar in each of a forward path and a return path. Processing equipment. 2. A semiconductor device is reciprocated, and a dam bar connecting a lead frame of the semiconductor device is irradiated with a laser beam from a processing head in each of a forward path and a return path to remove the dam bar and perform the outward path. In the forward direction, the laser beam is irradiated around the position at a predetermined distance from the start end of the dam bar to remove the dam bar, and the return path is centered at a position at a predetermined distance from the start end of the dam bar along the return direction. A dam bar processing device for a semiconductor device that irradiates a laser beam to remove a dam bar. 3. Reflected light (or transmitted light) of illumination light applied to the periphery including the laser beam irradiation position of the processing head.
A photo sensor having a spot-shaped sensitive area is provided at a light receiving position and at a position where the appearance of the dam bar along the moving direction of the outward path or the returning path can be monitored. 3. The dam bar processing apparatus of a semiconductor device according to claim 2, wherein a dam bar start end is detected, and a laser beam is emitted around the position at the predetermined distance from the detected start end.