JPH09201685A - Laser processing equipment - Google Patents

Abstract

(57) Abstract: In a laser processing apparatus, not only when the processing positions are equidistant, but also when the processing positions are not equidistant, it is possible to process a predetermined processing position at high speed. To enable accurate and quick detection of the cause of erroneous processing due to light. An image of a work 1 is captured by a camera 29 and displayed on a monitor in advance. Then, the work 1 is moved by the XY table 21, and the dam bar 2 is sequentially cut while determining the irradiation position of the laser light 100 based on the reflected light of the detection light 200. At the time of this disconnection, a trigger signal TP ₁ for controlling the oscillation of the laser light 100 is generated based on the reflected light of the detection light 200, and the pulse from the pulse encoder 21a attached to the XY table 21 is counted for each generation thereof. , Laser light 100 based on the count value
The irradiation position of is superimposed and displayed on the image of the monitor 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus capable of processing a desired processing position at high speed,
In particular, it relates to a laser processing apparatus capable of accurately and quickly detecting the cause of erroneous processing due to laser light.

[0002]

2. Description of the Related Art Processing using pulsed laser light includes processing methods such as cutting, drilling, and welding.
It is used in manufacturing processes in various fields such as semiconductor devices. The configuration of a conventional laser processing apparatus will be described with reference to FIGS. 8 and 9.

As shown in an example of FIG. 8, a conventional laser processing apparatus has a laser oscillator 30 including a laser head 31 and a laser power source 33, a processing optical system 32, and a work 40 which is a workpiece. In horizontal plane (in XY plane)
To move the XY table 41, the laser head 31, and the processing optical system 32 that are movable in the vertical direction (the Z-axis direction).
A main controller 43 is provided for automatically or manually controlling the movement of the table 42 and the XY table 41 in the horizontal plane, the movement of the Z table 42 in the vertical direction, and the oscillation of the laser oscillator 30.

The laser power source 33 is composed of a laser controller, a stabilizing power source, a capacitor section and a switch section which are not shown. In accordance with the voltage value commanded by the laser controller, the supplied AC current is converted to DC by the stabilized power supply, supplied to the capacitor unit, and the charge accumulated in the capacitor unit is based on the predetermined opening / closing timing of the switch unit. Is discharged to an excitation lamp (not shown). The opening and closing of the switch unit is performed according to a trigger signal that commands a pulse width and a pulse frequency from the laser controller. As described above, the pulsed laser light is emitted from the laser head 31.

The laser head 31 has a built-in beam shutter (not shown). The beam shutter opens and closes to turn on / off a pulsed laser beam.
Then, the irradiation of the laser light to the work 40 is controlled. That is, the beam shutter is opened when the workpiece 40 is processed, and the beam shutter is closed when the workpiece 40 is not processed.
The opening / closing operation time of this beam shutter is 100 ~ 300ms
It is about ec, and the control is performed from the laser controller described above, but it is also possible to perform the control from the main controller 43 via the laser controller.

A case will be described in which the dam bar of a QFP type semiconductor device (hereinafter also referred to as an IC package, for example) having leads extending in four directions is removed (cut) using the above laser processing apparatus. 9A is a plan view of the IC package, and FIG. 9B is an enlarged view of a B portion of FIG. 9A. As shown in FIGS. 9A and 9B, the dam bar 2 connects the pins (leads) of the lead frame used for the IC package, plays a role of blocking the resin when the IC package is molded, and the lead. It serves to reinforce the frame pins and is the part that is removed at the end of the manufacturing process. The processing procedure for removing the dam bar 2 with a pulsed laser beam will be described by taking as an example the case where the removal (cutting) of the K point in FIG. 9B is completed and then the L point is removed. Like

(1) Work 4
The laser beam irradiation position on 0 is moved in the direction from point K to point L in FIG. 9B (the positive direction of the X axis). However, the X axis and the Y axis are defined as shown in FIG. (2) Positioning is performed at point L, and the XY table 41 is stopped. (3) Open the beam shutter. (4) The dam bar 2 at the point L is removed by irradiating laser light. (5) Close the beam shutter.

By repeating the processing steps (1) to (5) above, the dam bars 2 on the four sides of the IC package shown in FIG. 9A are sequentially removed. At this time, XY
The movement and stop of the table and the opening and closing of the beam shutter are executed according to a program previously input to the main controller 43. Further, during this period, the laser light constantly oscillates in a pulse shape, or oscillates in synchronization with the opening of the beam shutter, and these controls are performed by the laser controller.

As a conventional technique relating to a laser processing apparatus or a laser processing method suitable for removing a dam bar, there is one described in Japanese Patent Laid-Open No. 142968/1994. In this conventional technique, a detection unit that detects the presence or absence of a work piece in the vicinity of a processing position and generates a corresponding detection signal, a rectangular wave signal generation unit that generates a rectangular wave signal based on the detection signal, and a rectangular wave thereof. There is disclosed a laser processing apparatus including a control unit that controls oscillation of pulsed laser light so that the pulsed laser light is irradiated at a timing based on a wave signal.

[0010]

The size of the dam bar of the above IC package is about 0.1 to 0.3 mm in width and 0.
Since it is about 15 mm, when removing the dam bar, one pulse of laser light can be removed sufficiently. Therefore, the time required for the actual processing corresponds to the pulse width of the pulsed laser light, which is about 0.1 to 1 msec. However, in the processing procedure of the prior art described in the above (1) to (5), the opening / closing operation time of the beam shutter is 20.
Depending on 0 to 600 msec and the moving time of the table, it takes about 1 sec to remove one dam bar, and it takes too much processing time in consideration of the number of cut dam bars and the number of manufactured IC packages.

In general, the pitch of the pins (leads) is often the same. However, there are manufacturing errors in the lead frame, distortion due to the temperature history when molding with resin, external force due to handling, and other factors. It may be deformed depending on the cause, and may not always be at the same pitch when the dam bar is removed. In the dam bar removal method described in the above (1) to (5), the locations where the dam bars are removed are registered in the main controller in advance as a program. However, in this method, the pins are not at equal pitch. In the worst case where it is not possible to cope with this and further the manufacturing error or deformation accumulates and the error increases, there is a possibility that the portion of the lead frame to be left may be damaged.

On the other hand, according to the prior art described in Japanese Patent Application Laid-Open No. 6-142968, a desired processing position can be processed at a high speed not only when the processing positions are at equal intervals but also when they are not at equal intervals. Therefore, even when the pins are not arranged at the same pitch but are arranged irregularly, it is possible to cope with the dam bar removal to some extent.

However, in the above-mentioned conventional technique, the amount of reflected light of the detection light is reduced due to the scattering of the molten metal on the surface of the lead frame caused by the laser light irradiation, and the part where the amount of reflected light is reduced is mistakenly recognized as the edge of the lead. There is a possibility that the laser light for processing may be erroneously emitted. On the other hand, a defect in the material of the lead frame, a defect in the edge state of the lead before processing, a defect in the combustion assist and the assist gas for removing molten metal, and a signal for laser oscillation. There is a possibility that the processing circuit may be erroneously processed due to a cause other than the erroneous detection of the processing position, such as a defect in the processing circuit (for example, the delay time does not become as set). Whether or not laser processing is performed at the wrong position in this way is discovered when processing is performed using a test piece for setting the processing conditions before processing the actual product, or the actual product is processed. It will be discovered at the time of the inspection after doing. In any case, the confirmation (inspection) of whether or not there is erroneous processing is performed by observing the result at a location outside the processing stage of the laser processing equipment, so it is possible to determine the cause of the erroneous processing. But it is difficult to distinguish. Therefore, it takes time to find the defect and solve the cause, and there is a concern that the semiconductor device processed on the line before the defect is discovered becomes a defective product.

Further, the investigation of the cause of the above-mentioned erroneous processing is as follows.
Similarly, it is difficult not only to cut the dam bar of the semiconductor device but also to perform similar processing.

The object of the present invention is not only to process the machining positions at equal intervals, but also to process the predetermined machining positions at high speed not only at equal intervals, but also to prevent erroneous processing due to laser light. It is an object of the present invention to provide a laser processing apparatus capable of accurately and quickly detecting the cause.

[0016]

In order to achieve the above object, according to the present invention, a laser oscillator that oscillates a pulsed laser beam and a machining optical system that guides the laser beam to a machining position of a workpiece. And a laser processing apparatus having a conveying means for moving the workpiece and determining a processing position thereof, an image processing means for capturing and processing an image of the entire workpiece and displaying the image, and detecting light for the processing. Based on the detection signal from the detection light generating means for irradiating the vicinity of the position, the detection means for detecting the presence or absence of the workpiece based on the reflected light of the detection light and generating a corresponding detection signal, Control means for controlling the oscillation of the laser light so that the laser light is irradiated to a predetermined processing position of the work piece, and the movement amount of the conveying means is calculated based on the timing of the laser light irradiation, and the movement amount is calculated. Based on Serial image processing unit laser processing apparatus characterized by having an irradiation position calculation display means for displaying overlapping the irradiation position of the laser beam on the image due to is provided.

In the present invention configured as described above,
Prior to processing, an image of the entire workpiece is captured by the image processing means, image processed and displayed. In the subsequent processing, first, the detection light generating means irradiates the detection light in the vicinity of the processing position, and the detection means detects the presence or absence of the workpiece based on the reflected light of the detection light and generates a corresponding detection signal. . Then, the control means controls the oscillation of the laser light based on the detection signal from the detecting means, and irradiates the laser light onto a predetermined processing position of the workpiece. As a result, the desired processing position is surely irradiated with the laser beam according to the information on the surface of the workpiece, and the processing is performed.

On the other hand, in the irradiation position calculation display means, the moving amount of the conveying means is calculated based on the timing of the irradiation of the laser beam, and based on the moving amount, the processing object displayed by the image processing means is displayed. The actual irradiation position of the laser light is superimposed and displayed on the image of the entire object. As a result, it is possible to immediately monitor where the actual processing position (information due to processing) by the laser light is located on the entire object to be visually compared. Therefore, when erroneous processing occurs, it can be accurately and quickly detected whether it is due to erroneous irradiation due to the deviation of the irradiation position of the laser beam or due to other causes.

For example, even though the actual irradiation position of the laser beam superimposed and displayed on the image of the whole workpiece before processing is proper, it is not actually cut or the cutting position is shifted. In this case, there is no problem in the laser light oscillation itself, and the cause other than erroneous detection of the processing position, that is, the cause of erroneous processing in the lead frame material, lead edge state, assist gas, signal processing circuit, etc. You can immediately see that there is.

Further, in the present invention, it is preferable that the control means has a trigger signal generation circuit for generating a trigger signal for laser light oscillation based on the detection signal, and the irradiation position calculation display means further comprises a movement amount of the conveying means. And a counter for inputting the trigger signal from the trigger signal generator and for sequentially counting the pulses from the encoder means corresponding to the time interval from the input of a certain trigger signal to the next input. It is preferable to have a circuit and image position calculation means for calculating each of the irradiation positions of the laser light on the image from the count value of the counter circuit.

In the above case, since the pulse from the encoder means is counted by the counter circuit, it becomes possible to easily detect the moving amount of the carrying means, and the laser on the image is based on the count value corresponding to this moving amount. The light irradiation position can be calculated easily and accurately.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. However, in the following,
A semiconductor device (IC package) having mainly equally spaced pins is used as a work, and cutting of the dam bar will be described.

As shown in FIG. 1, the laser processing apparatus according to the present embodiment includes a laser oscillator 10 including a laser head 11 and a laser power source 13, a processing head 12, and a workpiece (semiconductor device) which is a workpiece. 1 mounted on the horizontal plane (X
A control unit 25 having an XY table 21 as a transfer means for moving in the Y plane), a Z table 22 for moving the laser head 11 and the processing head 12 in the vertical direction (Z-axis direction), a main controller 23 and a trigger unit 24. It is equipped. The main controller 23 automatically controls the movement of the XY table 21 in the horizontal plane, the movement of the Z table 22 in the vertical direction, and the oscillation of the laser oscillator 10. In addition, the XY table 21
Is a pulse encoder 2 that converts the amount of movement into pulses
1a is attached.

The laser power source 13 includes a stabilizing power source unit 130,
Capacitor section 131, switch section 132, AC power supply 13
3 and a laser controller 26. In the laser power supply 13, first, the AC current supplied from the AC power supply 133 is supplied to the stabilizing power supply unit 130, changed to DC according to the voltage value instructed by the laser controller 26, and supplied to the capacitor unit 131. Capacitor part 1
The charge supplied to the 31 at the above voltage value is supplied to the excitation lamp 110 provided in the laser head 11 by opening and closing the switch unit 132 according to a trigger signal TP ₂ (described later) from the laser controller 26. The excitation lamp emits light by the pulse-like charges, thereby exciting the laser medium and emitting a pulse-like laser beam.

The laser head 11 shown in FIG. 1 has a built-in beam shutter (not shown). This beam shutter is opened and closed to open the laser oscillator 1
ON / OFF pulsed laser light emitted from 0
Then, the irradiation of the laser light to the work 1 is controlled. That is, when processing the work 1, the beam shutter is opened,
When not processing, the beam shutter is closed. The operating time of this beam shutter is 100-300 msec
It is a degree. Further, ON / OFF control of the beam shutter is performed from the laser controller 26, but it is also possible to perform control from the main controller 23 via the laser controller 26.

Further, a camera 29 is provided in the vicinity of the processing head 12 so that an image of the entire work 1 can be taken in. The image data from the camera 29 is sent to the image processing device 27 and displayed on the monitor 28. To be done. Further, information sent from the laser controller 23 (information on the irradiation position of the laser beam) is also input to the image processing device 27 so that the information can be displayed in an overlapping manner on the image from the camera 29 as described later. It has become.

Further, as shown in FIG.
A dichroic mirror 120 and a condenser lens 121 having a high reflectance characteristic with respect to the wavelength of the laser light are provided inside, and this is similar to the configuration of a conventional laser processing apparatus. In the present embodiment, the detection light source 122 for generating the laser light as the detection light and the collimator lens 12 have the above-described configuration.
3, a detection optical system 127 including a half mirror 124, an imaging lens 125, and a photodetector 126 is added. As the detection light source 122, a laser light source such as a laser diode (semiconductor laser) is used. This detection optical system 127 is basically similar in configuration to the optical system of an optical pickup unit that reads a disk signal of a CD player. ing. Needless to say, the laser light used as the detection light is different from the laser light used for laser processing. Further, the illumination light may be used as the detection light without using the laser light.

A detection signal from the photodetector 126 is input to the trigger unit 24, and the trigger unit 24 receives a predetermined trigger signal TP according to a command from the main controller 23.
₁ is output to the laser controller 26 in the laser power supply 13. As shown in FIG. 3, the trigger unit 24 includes a comparator 241, a trigger signal generation circuit 242, a delay circuit 243, a gate circuit 244, and a counter circuit 245.
Is provided. The detection signal from the photodetector 126 input to the trigger unit 24 is binarized by the threshold value V _TH in the comparator 241, and the rectangular wave signal TP is obtained.
Is generated and the trigger signal TP ₀ synchronized with the falling edge of the rectangular wave signal TP is generated in the trigger signal generation circuit 242.
Is output. Further, the trigger signal TP ₀ is given a delay time T _D instructed by the main controller 23 in the delay circuit 243, and the gate circuit 24 serves as TP _D.
4 and is processed by the gate signal T _W (see FIG. 5) input from the main controller 23 to generate the trigger signal T _W.
It is output to the laser controller 26 as P ₁ .

On the other hand, a pulse based on the movement amount of the XY table 21 from the pulse encoder 21a is input to the counter circuit 245, and the pulse counting is started when the movement of the XY table 21 is started. The above-mentioned trigger signal TP ₁ is also input to the counter circuit 245, and the time interval between the input of a certain trigger signal TP _{1 and} the input of the next trigger signal TP ₁ , that is, the time interval at which each trigger signal TP ₁ is input. The pulse of the pulse encoder 21a corresponding to is counted, and the count value N is the main controller 23.
Is output to

As shown in FIG. 4, the laser controller 26 includes an input / output unit 260, a central processing unit 261, and a trigger circuit 262. The trigger circuit 262 synchronizes with the rising edge of the trigger signal TP ₁ from the trigger unit 24 and the central controller 261 from the main controller 23.
A trigger signal TP ₂ having a pulse width instructed by is generated and this trigger signal TP ₂ is input to the switch unit 132. The voltage value of the electric charge supplied to the capacitor unit 131 is
It is input to the central processing unit 261 from the input / output unit 260 and is instructed to the stable power supply unit 130 from the central processing unit 261. After that, the pulsed laser light oscillates according to the process described above.

Further, in the main controller 23, each irradiation position of the laser light on the image of the monitor 28 is calculated from the count value N, and the position data is input to the image processing device 27. Then, the irradiation positions of the laser light are displayed in an overlapping manner on the image of the work (semiconductor device) 1 on the monitor 28.

Returning to FIG. 2, the functions of the processing head 12 and the detection optical system 127 will be described. First, the laser beam 100 oscillated from the laser head 11 is transmitted to a bending mirror 120.
Then, the direction is changed, and the light is condensed by the condenser lens 121 and irradiated onto the work 1. The detection light 200 emitted from the detection light source 122 is made parallel by the collimator lens 123, reflected by the half mirror 124, passes through the bending mirror 120, and passes through the condensing lens 121 to the work 1.
An image is formed with a minute spot on the top. However, the detection optical system 12
By adjusting 7, the spot forms an image at a position separated by a distance δd from the condensing position of the processing laser light 100 oscillated from the laser head 11. Then, the detection light 200 reflected on the surface of the work 1 is
The information on the surface of the work 1 is detected as an electric signal by passing through the bending mirror 120 and the half mirror 124 and collected by a photodetector 126 by an imaging lens 125.

At this time, the condenser lens 121 and the imaging lens 1
With the combination of 25, the detection light 200 on the surface of the work 1
Is formed at the position of the photodetector 126. In addition, the laser head 11 is arranged so that the spot of the detection light 200 hits a portion slightly outside the dam bar 2.
Distance δd from the condensing position of the processing laser beam 100 from
Is determined. As a result, the photodetector 126 can detect the presence or absence of the pin, that is, the portion where the pin exists (hereinafter referred to as the web portion) 4 and the slit portion 3 (see FIG. 5). On the other hand, laser light 100 used for laser processing
By irradiating almost the center of the dam bar, the dam bar 2 to be cut can be cut based on the detection signal from the photodetector 126 as described later.

FIG. 5 is a time chart from the output of the detection signal from the photodetector 126 to the oscillation of the laser light.
However, in FIG. 5, the web portion 4 and the slit portion 3 when the work 1 is moved at a constant speed are schematically shown as changes with time. Prior to processing, an image of the entire work 1 before cutting the dam bar is captured in advance by the camera 29, processed by the image processing device 27 and displayed on the monitor 28, and then processing (dam bar cutting) is performed.

First, the work 1 is moved by the XY table 21 at a constant speed in the positive direction of the X axis, for example. At this time, point A in the drawing is the movement start position of the optical axis of the processing laser beam 100, the optical axis of the processing laser beam 100 moves on the solid line locus 100A, and the movement ends at point B. To do. Further, the optical axis of the detection light 200 moves on the locus 200A of the broken line. At the time of the movement, the change in the detection signal detected by the photodetector 126 is high in the web portion 4 and low in the slit portion 3 as shown in FIG. Further, as shown in FIG. 5, the web portion 4 and the slit portion 3 of the work 1 are
Are arranged at the same pitch, the XY table 21 moves at a constant speed, and thus the detection signal is detected as a waveform having a constant period. On the other hand, when the web portion 4 and the slit portion 3 of the work 1 are not arranged at the same pitch, the detection signal is detected as a waveform having a time change proportional to the change in the pitch.

This detection signal is input to the trigger unit 24 and binarized into a rectangular wave signal TP based on a predetermined threshold value V _TH shown by the broken line in the figure, and the trigger signal generation circuit 2
42 is input. The trigger signal generation circuit 242 outputs a trigger signal TP ₀ based on the fall of the rectangular wave signal TP, and the trigger signal TP ₀ is input to the delay circuit 243. In the delay circuit 243, the trigger signal TP ₀
The delay time T _D commanded by the main controller 23
Is given, and the gate circuit 244 is provided as a trigger signal TP _D.
Is input to

Since the sections C and D at both ends of the loci A and B in FIG. 5 are originally sections that do not need to be processed, it is necessary to discard the detection signal of the photodetector 126 for this section. The gate circuit 244 is a circuit for removing the detection signals corresponding to the sections C and D, and when the gate signal T _W input from the main controller 23 is ON,
That is, the trigger signal TP _D from the delay circuit 243 is output as it is as the trigger signal T _{1 in the} processing range, and nothing is output when the gate signal T _W is OFF. The gate width W of the gate signal T _W is input to the main controller 23 in advance based on the processing range (design value).

The trigger signal TP ₁ from the gate circuit 244
Is input to the trigger circuit 262 of the laser controller 26, from the trigger circuit 262, the trigger signal TP ₂ in synchronization with the rising edge of the trigger signal TP ₁ is output.
The pulse width of the trigger signal TP ₂ is instructed from the main controller 23 as described above through a central portion 261. Further, the trigger signal TP ₂ is input to the switch unit 132, and the switch unit 132 is turned on in synchronization with the rise of the trigger signal TP ₂ to supply the electric charge from the capacitor unit 131 to the excitation lamp 110.
_In synchronization with the fall of ₂ , the switch unit 132 is turned off, and the supply of charges to the excitation lamp 110 is stopped. Above manner, pulsed laser light synchronized with the trigger signal TP ₂ to oscillate. Although the pulse laser light in the figure actually has a pulse waveform having a certain width, it is shown in a linear shape in the figure because the width is much shorter than other signals.

The delay time T _{D to} be given by the delay circuit 243 is determined by the delay in the trigger circuit
The laser beam is radiated to a predetermined position of the dam bar 2 based on the delay in the laser beam, the delay until the laser oscillation, the moving speed of the work 1, the width of the slit portion 3 of the work 1, and the like. Usually, the delay time T _D is determined so that the center of the dam bar 2 is irradiated with the laser beam.

Further, the output of the count value N from the counter circuit 245 is performed every time the trigger signal TP ₁ is generated, so that it is almost simultaneous with the output of the pulsed laser light as shown in FIG. That is, the output timing of the count value N corresponds to the irradiation timing of the laser light 100. However, here, for simplification, the time required for calculation and processing in the main controller 23, the image processing device 27, and the like can be ignored.

FIG. 6 is a flowchart showing a procedure for monitoring the position where the laser beam 100 is actually emitted, based on the pulse count value N of the pulse encoder 21a in the counter circuit 245. First, when the movement of the XY table 21 is started, a processing start command is sent from the main controller 23 to the counter circuit 245 (step S101). As a result, the pulses based on the movement amount of the XY table 21 from the pulse encoder 21a are counted (step S102). Next, the gate circuit 24
Counting is continued until the trigger signal TP ₂ is output from 4 (step S104). When the trigger signal TP ₂ is output, the count value N at that time is output from the counter circuit 245 to the main controller 23 (step S10).
5).

Next, in the main controller 23,
Based on the count value N, each irradiation position of the laser light on the image of the monitor 28 is calculated (step S106), and the calculated position data is sent to the image processing device 27 (step S107), and the original work 1 is processed. The irradiation positions of the laser light 100 are displayed in an overlapping manner on the image based on the position data. Then, the above steps S104 to S108 are repeated until the last dam bar 2 is cut (step S103). Note that there are a method of clearing the count value N each time the laser beam 100 is irradiated and a method of integrating the count value N for each irradiation, but either method may be adopted.

When the cutting of all the dam bars 2 is completed as described above, the count value of the counter circuit 245 is cleared.

FIG. 7 is a diagram showing an example of a situation in which a dam bar of a QFP type semiconductor device (IC package) having leads extending in four directions is cut. As shown in FIG. 7A, the trajectory 1
The dam bar 2 is cut in the order of 00a, locus 100b, locus 100c, and locus 100d. In this case, FIG. 7B is a diagram showing how the irradiation position of the laser beam 100 can be monitored. Further, in FIG. 7B, the actual irradiation position of the laser light 100 is indicated by +, and the cutting is completed up to the vicinity of the center of the locus 100c.
From the center of the left side of the figure, the left side and the left side show the state of being unprocessed (cutting not completed).

According to the present embodiment as described above, the image of the work 1 is captured by the camera 29 and displayed on the monitor 28 before the processing, and the detection light 20 is emitted during the processing.
Every time the trigger signal TP ₁ for controlling the oscillation of the laser light 100 is generated based on the reflected light of 0, the pulse from the pulse encoder 21a attached to the XY table 21 is counted, and the laser based on the count value is counted. Light 10
Since the irradiation position of 0 is displayed on the image of the monitor 28 in an overlapping manner, the actual processing position by the laser beam 100 can be immediately monitored and visually compared with the entire image of the workpiece 1 before processing. Therefore, if erroneous processing occurs, it may be due to erroneous irradiation due to the deviation of the irradiation position of the laser beam 100, or other causes such as the material of the lead frame, the edge condition of the lead, the assist gas, the signal processing circuit, etc. It is possible to accurately and swiftly detect whether it is due to the cause and investigate the cause of the defect. In addition, it is possible to quickly set and change conditions for recovery work when the device is started up or when a problem occurs.

Further, since the pulse from the pulse encoder 21a is counted by the counter circuit 245, the movement amount of the XY table 21 can be easily detected, and the irradiation position of the laser beam 100 on the image of the monitor 28 can be easily adjusted. And it can be calculated accurately.

In addition to the above, by monitoring the entire image of the workpiece 1 before processing and the actual processing position by the laser beam 100, the delay circuit 243 is actually used during processing.
It is also known how much the delay time T _D given by ## EQU1 ## deviates from the set delay time T _D , and it is possible to estimate the performance of the circuit, the element and the like.

[0048]

According to the present invention, the image of the entire workpiece is captured and displayed by the image processing means prior to the processing, and during the processing, the conveying means is based on the timing of laser light irradiation. Calculates the moving amount of the laser beam and displays the actual irradiation position of the laser light on the above image based on the moving amount, so it is possible to visually compare the actual processing position with the whole image before processing. You can

Therefore, when erroneous processing occurs, it is possible to accurately and promptly detect whether it is due to erroneous irradiation due to the deviation of the irradiation position of the laser light or due to other causes, and the problem is caused. You can investigate the cause. In addition, it is possible to quickly set and change the conditions for restoration work when the device is started up or when a problem occurs, and when test processing is required for this reason, the amount of test pieces for test processing can be reduced. . Furthermore, since the number of defective products decreases, the product manufacturing cost can be reduced.

In addition to the above, since the entire image before processing and the actual processing position are monitored, it is possible to estimate the performance of circuits and elements.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a laser processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a processing head inside and a detection optical system in the laser processing apparatus of FIG.

FIG. 3 is a diagram illustrating a configuration of a trigger unit in FIG. 1;

FIG. 4 is a diagram illustrating a configuration of a laser controller of FIG. 1;

FIG. 5 is a time chart showing the output of the detection signal from the photodetector to the oscillation of the laser light and the output from the counting circuit.

FIG. 6 is a flowchart showing a procedure for monitoring a position where laser light irradiation is actually performed based on a count value in a counter circuit.

FIG. 7 is a diagram showing an example of a situation in which a dam bar of a QFP type semiconductor device (IC package) having leads extending in four directions is cut.

FIG. 8 is a schematic diagram of a configuration of a conventional laser processing apparatus.

9A is a diagram showing an IC package having a dam bar, and FIG. 9B is an enlarged view of a portion B in FIG. 9A.

[Explanation of symbols]

 1 Work (semiconductor device or IC package) 2 Dam bar 3 Slit part 4 Web part 10 Laser oscillator 11 Laser head 12 Processing head 13 Laser power supply 21 XY table 21a Pulse encoder 22 Z table 23 Main controller 24 Trigger unit 25 Control unit 26 Laser controller 27 Image Processing Device 28 Monitor 29 Camera 100 Laser Light 110 Excitation Lamp 120 Dichroic Mirror 121 Condensing Lens 122 Detection Light Source 123 Collimator Lens 124 Half Mirror 125 Imaging Lens 126 Photodetector 127 Detection Optical System 130 Stabilizing Power Supply 131 Condenser Part 132 Switch unit 133 AC power supply 200 Detection light 241 Comparator 242 Trigger signal generation circuit 243 Delay circuit 244 Gate Circuit 245 counter circuit 260 input / output unit 261 central processing unit 262 trigger circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Shirai, 650 Kintatemachi, Tsuchiura City, Ibaraki Prefecture, Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. (72) Yoshiaki Shimomura, 650, Jinmachicho, Tsuchiura City, Ibaraki Ceremony Company Tsuchiura Plant (72) Inventor Shinya Okumura 650 Kintatecho, Tsuchiura City, Ibaraki Prefecture Hitachi Construction Machinery Co., Ltd. Tsuchiura factory

Claims (2)

[Claims] 1. A laser oscillator that oscillates pulsed laser light, a processing optical system that guides the laser light to a processing position of a workpiece, and a conveying unit that moves the workpiece and determines the processing position. A laser processing apparatus having: an image processing unit that captures an image of the entire workpiece, performs image processing and displays the image; detection light generation unit that irradiates detection light in the vicinity of the processing position; and reflection of the detection light. Detecting means for detecting the presence or absence of the workpiece based on light and generating a corresponding detection signal, and laser light is irradiated to a predetermined processing position of the workpiece based on the detection signal from the detecting means. Control means for controlling the oscillation of the laser light, and the movement amount of the conveying means is calculated based on the timing at which the laser light is emitted, and the movement amount of the conveying means is calculated based on the movement amount. Laser processing apparatus characterized by having an irradiation position calculation display means for displaying overlapping the irradiation position of the laser light. 2. The laser processing apparatus according to claim 1, wherein the control means has a trigger signal generation circuit for generating a trigger signal for the laser light oscillation based on a detection signal, and the irradiation position calculation display means. Encoder means for converting the movement amount of the carrying means into pulses, and inputting a trigger signal from the trigger signal generating section and sequentially counting the pulses from the encoder means corresponding to the time interval at which each trigger signal is input. A laser processing apparatus comprising: a counter circuit; and an image position calculation means for calculating each of the irradiation positions of the laser light on the image from the count value of the counter circuit.