JPH09205169A - Laser processing equipment and dam bar processing equipment - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: Even when the machining positions are not evenly spaced due to the deformation of the workpiece, the individual machining positions can be controlled according to the deformation, and the machining positions can be controlled. Provided are a laser processing device and a dam bar processing device capable of high-speed processing. SOLUTION: A detection light is applied to a work 1 from a detection light source 122, the reflected light is guided to a target 125a, and a photodetector 125 provided in openings W ₀ and W ₁ of the target 125a.
Detect with A and B. Then, in the calculator 245, referring to the data in the data table 244 based on the output signal level from the photosensor 125B at the time when the signal from the photosensor 125A reaches the threshold level, the set value of the slit unit 3 is changed. The deviation Δs of
The delay time t ₁ is calculated from Δs, and the irradiation position of the pulse laser light is controlled based on the delay time t ₁ .

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, and a dam bar processing apparatus suitable for cutting and removing a dam bar in a semiconductor device.

[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. 10 and 11 show the configuration of a conventional laser processing apparatus.
This will be described with reference to FIG.

As shown in an example of FIG. 10, 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. XY table 41 and laser head 31 which can be moved in the horizontal plane (in the XY plane)
Also, the movement of the Z table 42 and the XY table 41 for moving the machining optical system 32 in the vertical direction (Z-axis direction) in the horizontal plane, the movement of the Z table 42 in the vertical direction, and the oscillation operation of the laser oscillator 30 are automatically performed. A main controller 43 that is manually controlled is provided.

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 to 30 each.
It is about 0 msec, 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.

Using the laser processing apparatus as described above, for example, removal of dam bars of a QFP type semiconductor device (hereinafter also referred to as an IC package) in which lead portions (hereinafter also referred to as pins) are extended in four directions, for example. A case of performing (cutting) will be described. FIG. 11A is a plan view of the IC package, and FIG. 11B is an enlarged view of part B of FIG. 11A. FIG.
1 (a) and 1 (b), the dam bar 2 is
It connects the pins (leads) of the lead frame used for the package, has the role of blocking the resin when molding the IC package, and the role of reinforcing the pins of the lead frame, and is removed at the end of the manufacturing process. It is a part. 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. 11B is completed and then the L point is removed. Like

(1) Work 4
The laser beam irradiation position on 0 from the point K in FIG. 11 (b) to L
Move in the direction of the point (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.

[0008] By repeating the above processing steps (1) to (5), the IC package 4 shown in FIG.
Dam bars 2 on the side 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 equal, but the manufacturing error of the lead frame, the distortion due to the temperature history when molding with the resin, the external force due to the handling, and the like. It may be deformed by the cause of, and the pitch may not always be equal when removing the dam bar. 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 the manufacturing error or deformation is accumulated and the error increases, the lead portion which should 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, the above-mentioned Japanese Laid-Open Patent Publication No. 6-14296.
In the prior art described in Japanese Patent No. 8, there is no consideration for deviation due to deformation of the lead portion of the semiconductor device (IC package) to be processed. That is, the delay time to be given to the signal for controlling the oscillation of the pulsed laser light is a constant value regardless of the deformation of the lead frame, and the size of the gap between the lead parts (hereinafter, appropriately referred to as the slit part), that is, the size of one dam bar. However, the pulsed laser light can always be applied only to a position at a constant distance from the side surface of the lead (hereinafter, also referred to as a web portion as appropriate) even when the pulse laser light changes. When cutting the dam bar part, it is ideal to process the center (center of the adjacent lead part) in consideration of bending formability and accuracy of the lead in the subsequent process.
In the case of the above-mentioned conventional technique, not only the center of the dam bar portion cannot be processed, but also when the lead portion pitch is extremely deviated, the lead portion itself which should not be processed is processed. Also becomes.

An object of the present invention is to control individual machining positions according to the deformation even when the machining positions are not evenly spaced due to the deformation of the workpiece, and the machining positions can be controlled. An object of the present invention is to provide a laser processing device and a dam bar processing device that can perform high-speed processing.

[0015]

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. In a laser processing apparatus including: a transporting unit that moves the workpiece and determines a processing position thereof, a detection light generating unit that irradiates the detection light in the vicinity of the processing position and a reflected light of the detection light. A detection means for detecting the presence or absence of the work piece at two locations separated by a certain distance and generating corresponding detection signals, and the distance between the two detection locations based on each of the detection signals. There is provided a laser processing apparatus, comprising: a control unit that controls the oscillation of pulsed laser light so that the laser light is irradiated to a processing position of a workpiece according to fluctuations.

Further, according to the present invention, a laser oscillator that oscillates a pulsed laser beam, a machining optical system that guides the laser beam to a machining position of the workpiece, and the workpiece that is moved to machine the workpiece. A dam bar processing apparatus that includes a conveying unit that determines a position and sequentially cuts the dam bar by sequentially moving the optical axis of the laser light while irradiating the dam bar of the semiconductor device with the laser light. In the above, detection light generating means for irradiating the vicinity of the dam bar with detection light and presence / absence of a lead near the dam bar at two locations separated by a certain distance based on the reflected light of the detection light are detected. A laser beam is emitted to the processing position of the dam bar according to the variation of the distance between the two detection positions based on the detection means for generating a signal and each of the detection signals. Dam bar processing apparatus characterized by comprising a control means for controlling the oscillation of so that pulsed laser light is provided.

In the present invention configured as described above,
The detection light generation means generates detection light for detecting the presence or absence of the work piece in the vicinity of the processing position, the detection means detects the reflected light from the work piece, and generates a detection signal corresponding to the light. However, at this time, the reflected light is detected from two detection positions separated by a certain distance. Further, a detection signal corresponding to the detection result of one of the two detection positions of the detection means is input to the control means, and the control means controls the oscillation of the laser light based on the detection signal, Processing is performed by irradiating laser light according to information on the surface of the workpiece.

In this way, the workpiece is scanned at a constant speed relative to the detection means while detecting the reflected light from the two detection positions separated by a constant distance, and thus the two detection positions are detected. The time when the presence or absence (brightness) of the workpiece is detected can be known. Therefore, the reference value of the time difference between the detection times at the two detection positions is preset based on the design value of the pitch of the processing position (corresponding to the presence or absence of material) of the workpiece, and the actual detection time When compared with the time difference, it becomes possible to measure the deviation of the processing position from the design value.

From the above, even when the machining positions are not evenly spaced due to the deformation of the workpiece, the individual machining positions can be controlled according to the deformation, and the machining positions can be operated at high speed. Can be processed with.

Further, for example, when cutting the dam bar using the laser processing apparatus of the present invention, control is performed so that the processing position comes to the center of the gap between the lead portions in accordance with the deformation of each dam bar or the lead portion. By doing so, it is possible to always reliably cut the center of the dam bar regardless of any deformation.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. However, in the following,
The removal of the dam bar of the IC package having mainly equally spaced pins 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 work 1 (IC package) which is a workpiece. ) Is mounted and moves in the horizontal plane (in the XY plane) as a transfer means, 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. A control unit 25 having 24 is provided. The main controller 23 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 laser oscillator 1.
The oscillation operation of 0 is automatically controlled.

The laser power supply 13 includes a stabilized power supply 130,
It has a capacitor section 131, a switch section 132, and a laser controller 134. With this laser power supply 13,
First, the AC current supplied from the AC power supply 133 is supplied to the stabilized power supply unit 130, converted into DC according to the voltage value commanded by the laser controller 134, and supplied to the capacitor unit 131. The electric charge supplied to the capacitor unit 131 at the above voltage value follows the predetermined pulse width by the signal from the laser controller 134, and the switch unit 132.
Is supplied to the excitation lamp 110 provided in the laser head 11. The excitation lamp 110 emits light due to this pulse-shaped electric charge, whereby the laser medium is excited and pulsed laser light is emitted.

The processing head 12 has a detection light source 12 which will be described later.
2 and two photosensors 125A, 1 as detecting means
25B is provided with a certain distance, and the photo sensor 1
The detection signals from 25A and 125B are trigger units 24.
The trigger unit 24 outputs a rectangular wave signal P (described later) to the laser controller 134 in the laser power supply 13 by a command from the main controller 23 and internal calculation processing described later.

Further, as shown in FIG. 2, the trigger unit 24 has a comparator 241 as a comparison means composed of an operational amplifier and a delay circuit 2 as a delay means.
42, an AD converter 243, a data table 244, and a calculator 245. The detection signal from the photo sensor 125A is binarized (digitized) by the comparator 241 to generate the rectangular wave signal P ₀ , and the delay circuit 2
At 42, the rectangular wave signal is given a delay time t ₁ instructed by a calculator 245 described below, and is output to the laser controller 134 as a rectangular wave signal P. On the other hand, the detection signal from the photo sensor 125B is the AD converter 243.
Is digitized by and the data signal A is generated.
45 is input. A command value from the main controller 23 is given to the arithmetic unit 245, and the AD converter 24
3 receives the data signal A, a correction value based on the data signal A is calculated with reference to the data in the data table 244, and the command value from the main controller 23 is corrected to delay the delay time t _1. Circuit 242
Give to. The laser controller 134, to which the rectangular wave signal P from the delay circuit 242 is input, follows the process as described above and based on the rectangular wave signal P, the switch unit 132.
Is operated to oscillate the laser oscillator 10 to oscillate pulsed laser light.

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 laser light are provided inside, and this is similar to the configuration of a conventional laser processing apparatus. In the present embodiment, in addition to the above configuration, the detection light source 122,
The dichroic mirror 123, the image forming lens 124, the target 125a, and the above-mentioned photosensors 125A and 125B are added as a detection optical system 127.

The processing head 12 and the detection optical system 127
The function of will be described. First, the beam of the pulsed laser light 100 output from the laser head 11 is a dichroic mirror 1.
The direction is changed at 20, the light is condensed by the condenser lens 121, and the work 1 is irradiated with the light. Further, the detection light 200 emitted from the detection light source 122 is changed in direction by the dichroic mirror 123, passes through the dichroic mirror 120, and passes through the condenser lens 12.
The light is condensed at 1 to become illumination light around the laser processing portion on the work 1. The light reflected on the surface of the work 1 passes through the dichroic mirror 120 and the dichroic mirror 123, is condensed by the imaging lens 124, and hits the target 125a. Then, part of the reflected light that hits the target 125a is input to the photosensors 125A and 125B through the two openings provided in the target 125a. At this time, the combination of the condenser lens 121 and the imaging lens 124 causes the image on the work 1 to be detected by the photo sensors 125A, 1A.
When the image is formed at the position of 25B, the image on the work 1 is narrowed down by the aperture of the lens, and on the target 125a,
For example, an image is formed as shown in FIG.

FIG. 4 shows the target 12 as described above.
5a is an example of an image formed on 5a. In FIG.
A state where an image is formed in the vicinity of the dam bar 2 of the work 1 is shown. In this image, among the portions (hereinafter, referred to as slit portions) 3 and 4 where the lead portion (pin) 5 does not exist,
Only the slit portion 4 inside the dam bar 2 is filled with the resin mold when the IC package is sealed. Then, with respect to this image, there are openings W ₀ and W ₁ at two locations indicated by hatched areas, and the photosensor 125 is located at the location of the openings.
A and 125B are attached.

As described above, the light in the opening W ₀ of the image of FIG. 4 is detected by the photosensors 125A and 125B, but the openings W ₀ and W ₁ are located outside the dam bar 2. ing. That is, when the X axis and the Y axis are set as shown in the figure, the openings W ₀ and W ₁ are provided at positions slightly displaced from the center of the image in the negative direction of the Y axis. In this state, by moving the XY table 21 in the negative direction of the X-axis in the drawing, the photosensors 125A and 125B have the lead portions (pins) 5, that is, the portion (web) where the lead portions 5 are present and the slit portion 3. Can be detected.
On the other hand, the center of the emitted pulsed laser light is located at the center of the image in FIG. With this configuration, the dam bar 2 to be cut can be cut as described below based on the detection signal from the photo sensor 125 as described below.

The operation of the pulse laser processing apparatus having the above configuration will be described. First, the work 1 is set on the XY table 21.
Thus, for example, when the image is moved in the negative direction of the X axis at a constant speed, the image on the target 125a shown in FIG. 4 also moves in the negative direction of the X axis. However, the photo sensor 125A,
Since 125B is fixed to the opening of the target 125a, the change in the detection signal which is the output from the photosensors 125A and 125B becomes high at the lead 5 and low at the slit 3 as shown in FIG. Becomes However, the detection signal here has a high output when the light is strong and a low output when the light is weak. Further, as shown in FIG. 5, if the webs 5 and slit portions 3 of the work are arranged at equal pitches, the XY table 21 moves at a constant speed, so that the detection signal is detected as a waveform having a constant cycle.
On the other hand, when the web 5 and the slit portion 3 of the work 1 are not arranged at equal pitches, the detection signal is detected as a waveform having a time change proportional to the pitch change.

Next, this waveform is input to the control means 24 and signal processing is performed. The detection signal from the photo sensor 125A is input to the comparator 241 of the trigger unit 24, and the detection signal is binarized based on a predetermined threshold level indicated by a broken line S in the figure to obtain a rectangular wave signal P.
_It becomes ₀ and is input to the delay circuit 242. Then, the delay circuit 242 outputs the binarized detection signal to the arithmetic unit 2
The delay time t ₁ instructed from 45 is given and input to the laser controller as a rectangular wave signal P.

FIG. 7 shows a time chart from detection by the photo sensor 125 to oscillation of pulsed laser light. Note that, in FIG. 7, the web 5 and the slit portion 3 when the work 1 is moved at a constant speed are schematically shown as changes with time. The web 5 of the work 1 as described in FIG.
The slit portion 3 is detected by the photo sensor 125, and the detection signal is binarized by the comparator 241 of the trigger unit 24 to become the rectangular wave signal P ₀ , and the delay circuit 24
At 2, the delay time t ₁ is given to form the rectangular wave signal P, which is input to the laser controller 134. Then, the switch unit 132 operates in response to the rising of the rectangular wave signal P, and the pulsed laser light oscillates. The oscillation of the pulsed laser light in the figure is actually a pulse shape, but since this pulse width is much smaller than the other signals, it is represented by a linear shape in FIG. 7.

Here, from the arithmetic unit 245 to the delay circuit 2
The delay time t ₁ given to 42 will be described. When the signal from the photosensor 125A at the position of one opening W ₀ in the target 125a reaches the threshold level, the comparator 241 to the AD converter 24
The AD start signal C ₁ is output to 3. Then, at that timing, the output signal from the photosensor 125B at the position of the other opening W ₁ is digitized by the AD converter 243, and the digital signal A is input to the calculator 245 as described above, and the calculator 245 is input. In the data table 24
The calculation is performed with reference to the data in 4. In the data table 244, the relationship between the signal level of the digital signal A and the width of the slit portion 3 (corresponding to the length of the dam bar 2) s is registered, as shown in FIG. The signal level of the digital signal A with respect to the design value s ₀ of the width of 3 is A ₀ . That is, if the signal level of the digital signal A is A ₀ , the slit portion 3 at that time is
Width will be that it is s ₀ as designed in, for example, the signal level of the digital signal A is assumed to be A _1, the actual width of the slit portion 3 is s _1, s ₀ is a design value It is shifted (larger) by Δs. Thus, based on the output signal level from the photo sensor 125B at the time when the signal from the photo sensor 125A reaches the threshold level, the actual width of the slit portion 3, that is, the deviation Δs from the set value of the slit portion 3 is set.
Is required.

FIGS. 9A to 9C show the relationship between the width of the slit portion 3 and the positions of the openings W ₀ and W ₁ . In (a), the width of the slit portion 3 is shorter than the design value s _{0 due} to deformation or the like, and Δs
Is negative, the width of the slit portion 3 is the design value s in (b).
_When there are ₀ ways and Δs is 0, (c) shows the case where the width of the slit portion 3 is longer than the design value s ₀ and Δs is positive due to deformation or the like. However, for the sake of simplicity, it is assumed that the distance between the openings W ₀ and W ₁ is separated by the design value s ₀ of the width of the slit portion 3, and FIGS. FIG. 9 is a diagram at a time when the signal from the photosensor 125A at the position of the opening W ₀ reaches the threshold level. The combination of the signal level A ₁ and the width s ₁ of the slit portion 3 in FIG. 8 corresponds to the case of FIG. 9C.

The calculation in the calculator 245 is performed as follows. The actual width s of the width of the slit portion 3 is S = s ₀ + Δs, using the deviation Δs between the actual width of the slit portion 3 obtained in the data table 244 and the design value s ₀ of the width of the slit portion 3. ... (1) Further, the moving speed of the work 1, that is, the moving speed of the XY table 21 is v, and the width of the slit portion 3 is the moving speed v.
Let t be the time required to move at, then t = (s ₀ + Δs) / v (2)

Here, t ₂ is the total delay time required for the binarization in the comparator 241, the delay in the element used, the delay until the pulse laser oscillation, etc., and t = (s ₀ + Δs) / v = 2 (t ₁ + t ₂ ) ... (3) If the delay time t ₁ in the delay circuit 242 is determined, oscillation of the pulsed laser light is detected by the photosensor 12
The actual slit portion 3 after the time t / 2 from the detection by 5A
The center of the dam bar 2 is cut off. Moreover, even if the dam bar 2 or the lead portion 5 is deformed, Δs is read by the calculator 245 from the data in the data table 244, and the formulas (1) to
Since the delay time t ₁ is determined by the calculation based on (3), the irradiation position of the pulse laser beam is controlled according to the deformation, and the center of the gap between the lead portions 5, that is, the center of each dam bar 2 must be cut. You can

In the above, the delay time t ₂ , the moving speed v of the XY table 21, and the design value s of the width of the slit portion 3 are set.
_It is assumed that ₀ is input to the main controller 23 in advance. Further, in the above description, the distance between the openings W ₀ and W ₁ is described as the design value s ₀ of the width of the slit portion 3, but by appropriately changing the data table 244 shown in FIG. , The distance between the openings W ₀ and W ₁ can be set to a _value other than s ₀ .

When the dam bar on one side of the work 1 is cut by the above operation, first, the locus passing through the dam bar 2, the moving speed of the work 1, that is, the moving speed v of the XY table 21, the width of the slit portion 3 of the work 1. w and delay time t ₂
Is input to the program of the main controller 23, and this program is run. Then, table 21
Moves at a constant speed, and pulsed laser light oscillates at a cycle determined by the pitch of the lead portion 5 and the slit portion 3 and the moving speed v of the table 21, and the dam bar 2 is cut.
Moreover, even if the dam bar 2 or the lead portion 5 is deformed, the center of the dam bar 2 is surely cut according to the deformation.

According to the present embodiment as described above, in the arithmetic unit 245, the photo sensor 1 at the time when the signal from the photo sensor 125A reaches the threshold level.
Data table 24 based on the output signal level from 25B
Since the deviation Δs from the set value of the slit portion 3 is obtained with reference to the data in 4, the delay time t ₁ is calculated from Δs, and the irradiation position of the pulsed laser light is controlled based on the delay time t ₁ , Even if the dam bar 2 and the lead portion 5 of the work 1 are deformed, the center of the gap between the lead portions 5, that is, the center of each dam bar 2 can be cut reliably and at high speed according to the deformation.

It is also possible to cut not at the center of each dam bar 2 but at a position displaced from the center by a predetermined distance. In this case, the delay time may be set again by shifting from the delay time t ₁ obtained by the above equation (3) by a time corresponding to the distance displaced from the center. Further, although the detection positions of the detection light are two in the above, the detection positions may be three or more and the processing position may be controlled based on the detection result at each detection position.

Further, although the present embodiment has been described by taking the application to dam bar cutting as an example, the present invention shows the presence or absence of other workpieces having different optical characteristics, that is, the presence of a patterned material and the change of reflectance. It can also be applied to an object to be processed. For example, the present invention can be applied to the case where it is desired to make a hole for a through hole on a copper wiring of a printed wiring board. This is because the surface of the copper wiring pattern on the printed circuit board has a high optical reflectivity and the glass epoxy, which is the base material of the board, allows light to pass through, so it can be distinguished as a signal based on light and dark by the photo sensor. Because. Furthermore, by moving the detection position in the width direction of the copper wiring, the width of the copper wiring can be detected, so that the desired position of the copper wiring, for example, the center can be irradiated with laser light.

[0042]

According to the present invention, the deviation from the design value is calculated based on the detection result of the presence or absence (brightness) of the workpiece at each of the two detection positions, and the pulse laser is calculated based on the calculation result. Since the irradiation position of light is controlled, even when the processing positions are not evenly spaced due to the deformation of the workpiece,
Each processing position can be controlled according to the deformation, and the processing position can be processed reliably and at high speed.

When cutting the dam bar of the semiconductor device, the machining position is controlled so as to come to the center of the gap between the lead parts in accordance with the deformation of the individual dam bars and the lead parts. The center of the dam bar can be reliably cut regardless of the situation.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration of a trigger unit shown in FIG.

FIG. 3 is a schematic diagram of a configuration of a processing head and a detection optical system in FIG.

4 is an example of an image in the vicinity of the dam bar formed on the target of FIG.

FIG. 5 is a diagram showing a correspondence relationship between a dam bar and a detection signal from a photodetector.

FIG. 6 is a diagram showing a situation in which a waveform detected by a photo sensor is binarized by a trigger unit.

FIG. 7 shows a time chart from detection by a photo sensor to oscillation of pulsed laser light.

8 is a diagram showing an example of a relationship between a signal level of a digital signal A registered in a data table 244 and a width (corresponding to the length of the dam bar 2) s of the slit portion 3. FIG.

FIG. 9 is a diagram showing the relationship between the width of the slit portion and the positions of the openings in the two targets, where (a) shows the case where the width of the slit portion is shorter than the design value due to deformation or
(B) shows that when the width of the slit part is as designed,
FIG. 6C is a diagram showing a case where the width of the slit portion is longer than the design value due to deformation or the like.

FIG. 10 is a schematic diagram of a configuration of a conventional laser processing apparatus.

11A is a view showing a work (IC package) having a dam bar portion, and FIG. 11B is an enlarged view of a B portion in FIG. 11A.

[Explanation of symbols]

1 Work 2 Dam Bar 3 Slit Section 4 Slit Section 5 Lead Section 10 Laser Oscillator 11 Laser Head 12 Processing Head 13 Laser Power Supply 21 XY Table 22 Z Table 23 Main Controller 24 Trigger Unit 25 Control Unit 100 Pulse Laser Light 120 Dichroic Mirror 2 121 Collection Optical lens 122 Detection light source 123 Dichroic mirror 124 Imaging lens 125A, 125B Photo sensor 125a Target 127 Detection optical system 130 Stabilizing power supply section 131 Condenser section 132 Switch section 133 AC power supply 134 Laser controller 200 Detection light 241 Comparator 242 Delay circuit 243 AD converter 244 Data table 245 Operation unit W ₀ , W ₁ Opening

Front page continued (72) Inventor Shinya Okumura 650 Kazunachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant (72) Inventor Yoshiaki Shimomura 650 Jincho-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Inside the factory (72) Inventor Shigeyuki Sakurai 650 Kazutachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura factory (72) Inventor Yasushi Minomoto 650 Kintachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Engineering Co., Ltd. Within

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. In a laser processing apparatus including: a detection light generation unit that irradiates detection light near the processing position; and the presence or absence of the work piece at two locations separated by a certain distance based on the reflected light of the detection light. Laser light is irradiated to the processing position of the workpiece according to the variation of the distance between the two detection positions based on each of the detection means for detecting and generating a corresponding detection signal. And a control means for controlling the oscillation of the pulsed laser light. 2. A laser oscillator that oscillates a pulsed laser beam, a machining optical system that guides the laser beam to a machining position of a workpiece, and a conveying unit that moves the workpiece and determines the machining position. In a dam bar processing device that sequentially cuts the dam bar by moving the optical axis of the laser light relative to the semiconductor device while irradiating the dam bar of the semiconductor device with the laser light, Detecting light generating means for irradiating the vicinity of the dam bar, and detection for detecting the presence / absence of leads in the vicinity of the dam bar at two locations separated by a certain distance based on the reflected light of the detecting light and generating corresponding detection signals. Means for irradiating a laser beam to a processing position of the dam bar according to a change in the distance between the two detection positions based on each of the detection signals. A dambar processing apparatus comprising: a control unit that controls oscillation of pulsed laser light.