JPH10144843A - Dam bar repair cutting method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable uncut dam bar in various kinds of lead frames to be repair- cut in simple procedures with high precision in the case of repair-cutting the uncut dam bar even if the lead frame shape and the lead frame fixed position are hardly reproduced. SOLUTION: The distance of the material of a lead pin 4 along a locus L1 (data on the lead frame shape after dam bar cutting off) is detected using detecting beams so as to compare the detection results with the distance of the material of the lead pin 4 in the case the dam bar cutting off step is normally performed for detecting the uncut dam bar 3 according to the comparison results further to control the oscillation of the laser beams according to the detection results for irradiating the uncut dam bar 3 with the laser beams to be repair-cut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cutting of a dam bar in a semiconductor device (IC package) in which a semiconductor chip and a lead frame are sealed with a resin, and in particular, repairs and cuts an uncut dam bar after the dam bar cutting step. And a device for repairing and cutting dam bars.

[0002]

2. Description of the Related Art In a semiconductor device 1 in which a semiconductor chip and a lead frame are sealed with resin (hereinafter, appropriately referred to as an IC package), a dam bar 2 of the lead frame is cut after sealing with resin. This dam bar cutting is generally performed by using a comb-shaped press blade 90 as shown in FIG.
Is performed using a press or the like using a mold 90a having However, due to recent miniaturization of the lead pitch of the IC package and increase in the number of pins, the following inevitable problems occur in press cutting.

[0003] That is, as the lead pitch of the IC package becomes finer, the positioning accuracy of the press blade 90 becomes strict, and the strict positioning accuracy is demanded over the entire IC package having multiple pins. In addition, the thickness of the press blade 90 has been reduced with the miniaturization of the lead pitch. Therefore, when the positioning is insufficient, as shown in FIG. 9, the shape of the end face obtained by cutting the dam bar 2 by the press blade 90 (the position is indicated by oblique lines in the figure) is not symmetrical in the lateral direction. Under such a heavy load, the thin press blade 90 is easily broken. When the inspection is performed after the dam bar is cut, the inspection is not performed for all the IC packages. Therefore, even if the press blade 90 is damaged as described above, the dam bar is continuously cut for each package, and the sampling inspection is performed later. Until the operation is performed, the uncut dam bar 2 remains in a large amount of products.

[0004] The IC leaving the uncut dam bar in this way
The package can be repaired by manufacturing a mold suitable for the uncut place each time, but since the cost and manufacturing time are required, the above-mentioned products are often discarded as defective products.

On the other hand, laser processing does not require a die having a comb-shaped press blade as described above, and processing can be performed along a set locus. Therefore, selective processing of only uncut dam bars can be performed at low cost. It can be carried out. An apparatus configuration and a procedure for performing uncut dam bar repair cutting using a general laser processing apparatus will be described below with reference to FIGS. 10 and 11. The output form of the laser beam is continuous or pulsed. In the case where the thermal effect becomes a problem in fine processing, a pulsed laser with little thermal effect is often used. The description mainly focuses on the case where a laser processing apparatus is used.

As shown in FIG. 10, a conventional pulse laser processing apparatus mounts a laser head 31, a processing optical system 32, a laser power supply 33, and a work 40 which is a work to be processed on a horizontal plane (XY plane). ), The Z table 42 for moving the laser head 31 and the processing optical system 32 in the vertical direction (Z-axis direction), and the movement of the XY table 41 in the horizontal plane and the vertical movement of the Z table 42. A main controller 43 for automatically or manually controlling the operation and the oscillation operation of the pulsed laser light is provided. The laser head 31 and the laser power supply 33 constitute a laser oscillator 30.

The laser power supply 33 includes a laser controller 33a, a stabilized power supply section 33b, and a capacitor section 33c.
And a switch section 33d and an AC power supply section 33e. According to the voltage value commanded from the laser controller 33a, the AC current supplied from the AC power supply unit 33e is changed to DC by the stabilized power supply unit 33b,
c, and the electric charge stored in the capacitor unit 33c is discharged to the excitation lamp 31a of the laser head 31 via the switch unit 33d based on a predetermined opening / closing timing of the switch unit 33d. The opening and closing of the switch unit 33d is performed in accordance with a trigger signal instructing a pulse width and a pulse frequency from the laser controller 33a. As described above, the pulse laser light is emitted from the laser head 31.

The laser head 31 has a built-in beam shutter 31b.
By opening and closing, the irradiation of the pulse laser light to the work 40 is controlled. That is, when processing the workpiece 40, the beam shutter 31b is opened, and when not processing, the beam shutter 31b is closed. The opening / closing operation time of the beam shutter 31b is about 100 to 300 msec. The control is performed by the laser controller 33a described above, but it can also be performed by the main controller 43 via the laser controller 33a.

The cutting of the uncut dam bar using the above-described apparatus will be described. FIG. 11A is a plan view showing a simplified IC package, and FIG.
It is a B section enlarged view of (a). However, FIG. 11A mainly shows the position of the resin mold portion 5, and the detailed configuration of the lead frame is omitted. Further, the X axis and the Y axis are set as shown in the figure. As shown in FIG. 11 (b), the dam bar 2 connects each pin (hereinafter, appropriately referred to as a lead pin) 4 of the lead frame, and has a role of damming resin flowing out at the time of sealing with resin (resin). , Which serve to reinforce the lead pins 4 and are removed after the resin sealing process. The procedure for cutting the uncut dam bar 2 with a pulsed laser beam is, for example, as follows.

(1) A laser beam irradiation position is manually adjusted to a reference point O (see FIG. 11A) on a lead frame of an IC package. At this time,
The XY table 41 is moved. (2) Execute a program in which the distance from the reference point O is set in advance based on the design value. (3) The irradiation position of the laser beam is moved from the reference point O to the position A ₀ of the uncut dam bar 2. (4) Open the beam shutter 31b and cut the uncut dam bar 2. (5) Close the beam shutter 31b. (6) Return the irradiation position of the laser beam to the reference point O.

When there is an uncut dam bar 2 at a relatively same position with respect to a plurality of IC packages, the above-mentioned steps (2) to (6) are repeated to obtain an uncut dam bar 2 in units of IC packages or lead frames. Can be repaired and cut.

[0012]

When the uncut dam bar 2 is repaired and cut by the above-mentioned procedures (2) to (6), the reproducibility of the distance between the reference point O and the position A ₀ of the uncut dam bar 2 is improved. If it is enough, it can be processed without any problem. However, the precision of the processing position has become severe due to the miniaturization of the lead pitch,
In addition, the lead frame becomes less deformable due to thermal stress in the resin sealing process because the lead frame becomes less rigid due to finer lead pitch and more pins (generally, the lead pitch shrinks due to thermal stress). , The reproducibility is also low.

As described above, although the precision of the processing position is severe, the reproducibility of the dimensions of the lead frame in the IC package is low. Therefore, when the above procedures (2) to (6) are repeated, the laser light Is highly likely to shift (especially, in the case of FIG. 11B, easily shifts in the X-axis direction), and the possibility of cutting the lead pins 4 that should not be processed increases. In addition, in order to cut uncut dam bars for each lead frame in a plurality of IC packages, repair cutting is performed while automatically supplying the IC package (lead frame). In addition, the possibility of processing the lead pin 4 that should not be processed is further increased.

When the above-described dam bar cutting device is used as a dedicated device for repairing and cutting an uncut dam bar, every time the type of the lead frame changes, the work of measuring the position of the uncut dam bar and the like are performed each time. In addition, troublesome work such as editing a program necessary for repair cutting is required.

[0015] An object of the present invention is to repair and cut an uncut dam bar, even when the reproducibility of the lead frame shape and the reproducibility of the lead frame fixing position are low, without processing lead pins that should not be processed. Another object of the present invention is to provide a dam bar repair / cutting method and a device capable of repairing / cutting an uncut dam bar with high accuracy and repairing / cutting an uncut dam bar in various types of lead frames by a simple procedure.

[0016]

According to the present invention, there is provided a semiconductor device in which a semiconductor chip and a lead frame are sealed with a resin. In the dam bar repair cutting method performed by irradiating pulsed laser light, the semiconductor device is moved in a direction in which the dam bar is continuous while irradiating detection light to a position of the lead frame after dam bar cutting, and the detection light from the lead frame is detected. A detection signal is generated based on the reflected light, and based on the detection signal, a movement amount of the semiconductor device corresponding to an existing distance of the lead frame material at a detection position by the detection light is measured, and the measured semiconductor device is measured. And the value corresponding to the existing distance of the lead frame material when the dam bar is cut normally When the measured movement amount of the semiconductor device is larger than a value corresponding to the existing distance of the lead frame material when the dam bar is normally cut, if there is an uncut dam bar at the detection position by the detection light, A dam bar repair / cutting method is characterized in that the judgment is made and the oscillation of the laser beam is controlled so that the uncut dam bar is irradiated with the laser beam.

According to the present invention, there is provided a laser oscillator for oscillating a pulsed laser beam, a processing optical system for guiding the laser beam to a workpiece, and A transport device for moving and determining a processing position thereof, wherein the semiconductor chip and the lead frame are sealed with a resin. Detection light generating means for irradiating detection light to a position of the frame after dam bar cutting, detection means for emitting reflected light of the detection light from the lead frame and generating a detection signal in accordance with the detection result; For measuring the amount of movement of the transport means corresponding to the distance of the lead frame material at the position detected by the detection means based on the detection signal from the means. Means, a comparing means for comparing the movement amount measured by the measuring means with a value corresponding to the existing distance of the lead frame material when the dam bar is normally cut, and based on the comparison by the comparing means. When the movement amount measured by the measuring means is larger than the value corresponding to the existing distance of the lead frame material when the dam bar is normally cut, it is determined that there is an uncut dam bar at the detection position by the detecting means. And a control means for controlling the oscillation of the laser light so that the uncut dam bar is irradiated with the laser light.

In the present invention configured as described above,
The semiconductor device is moved in the direction along the dam bar while irradiating the detection light to the position of the lead frame after the dam bar is cut, and a detection signal is generated based on the reflected light of the detection light from the lead frame. On the basis of,
The movement amount of the semiconductor device corresponding to the existing distance of the lead frame material at the detection position by the detection light is measured. The amount of movement of the semiconductor device measured here includes information on the shape of the lead frame after cutting the dam bar. For example, if there is an uncut dam bar after the dam bar cutting step, the lead frame at that location The distance of the material should be longer than if the dam bar were cut normally. Therefore, a value (a value based on the design value) corresponding to the existing distance of the lead frame material when the dam bar is normally cut is set in advance, and this value is compared with the measured movement amount of the semiconductor device. If the measured movement amount of the semiconductor device is larger than the value corresponding to the case where the dam bar is normally cut, there is an uncut dam bar at the detection position by the above-described detection light. Then, the oscillation of the laser beam is controlled so that the uncut dam bar is irradiated with the laser beam.

As described above, the existence of the uncut dam bar is reliably detected based on the existing distance of the lead frame material along the direction in which the dam bars are connected, that is, the information on the shape of the lead frame after the dam bar is cut, and based on the detected information. Since the laser beam is irradiated on the uncut dam bar by controlling the oscillation of the laser beam, the uncut dam bar can be repaired and cut reliably and accurately according to the information of the lead frame. Therefore, even when the reproducibility of the lead frame shape and the reproducibility of the fixed position of the lead frame are low, the uncut dam bar at the desired position to be cut is accurately, reliably and based on the information of the lead frame shape. It is cut at high speed, and lead pins that should not be processed are not processed.

Moreover, even if the type of the lead frame is changed, the uncut dam bar can be repaired and cut based on the information of the target individual lead frame shape. This eliminates the need for troublesome work such as measurement work and editing of programs required for repair cutting, and it is also possible to repair and cut uncut dam bars in various types of lead frames by a simple procedure.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a repair / cutting device for a dam bar and a repair / cutting method thereof according to the present invention are shown in FIGS.
This will be described with reference to FIG. However, in the following, the repair cutting of the uncut dam bar after the regular dam bar cutting step of the semiconductor device (QFP type IC package) having pins at regular intervals will be described.

As shown in FIG. 1, a laser head 11 and a laser power supply 13
A laser oscillator 10, a processing head 12,
X as a transporting means for mounting a workpiece 1 (IC package) as a workpiece and moving it in a horizontal plane (XY plane)
Y table 21, laser head 11, and processing head 12
Table 22 for moving the table vertically (Z-axis direction),
A control unit 25 having a main controller 23 and a trigger unit 24 is provided. 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. Further, the XY table 21 is provided with an encoder 210 for detecting a moving amount of the XY table 21.

The laser power supply 13 includes a stabilized power supply 130,
Capacitor section 131, switch section 132, AC power supply section 1
33 and a laser controller 26. In the laser power supply 13, first, the AC current supplied from the AC power supply unit 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. . The charge supplied to the capacitor unit 131 at the above voltage value is supplied to the excitation lamp provided in the laser head 11 by opening and closing the switch unit 132 according to a predetermined pulse width according to a trigger signal TP ₂ (described later) from the laser controller 26. 110
Supplied to The excitation lamp 110 emits light by the pulse-like charges, whereby the laser medium is excited and pulsed laser light is emitted.

The laser head 11 shown in FIG. 1 has a built-in beam shutter 111. This beam shutter 1
Reference numeral 11 controls ON / OFF of the pulse laser light emitted from the laser oscillator 10 by opening and closing, and controls the irradiation of the work 1 with the laser light. That is, when processing the work 1, the beam shutter 111 is opened, and when not processing, the beam shutter 111 is closed. The opening and closing operation of the beam shutter 111 is controlled by the laser controller 26.
However, it is also possible to carry out from the main controller 23 through the laser controller 26.

Further, as shown in FIG.
A dichroic mirror 120 and a condenser lens 121 having high reflectance characteristics with respect to the wavelength of the laser light are provided therein, and these configurations are the same as those of a conventional laser processing apparatus. In the present embodiment, the above configuration includes a detection light source 122 that generates laser light (hereinafter simply referred to as detection light) 200 as detection light, a collimator lens 123, a half mirror 124, an imaging lens 125, and a photodetector 126. A detection optical system 127 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. It goes without saying that the laser light used as the detection light is different from the laser light for performing the laser processing.

As shown in FIG. 3, the trigger unit 24 includes a comparator 241 and a calculation unit 242. In this trigger unit 24, the detection signal from the photodetector 126 is the threshold V _TH is binarized (see FIG. 6) a rectangular wave signal TP ₀ in the comparator 241 is generated, the rectangular wave signal TP ₀ Is input to the calculation unit 242. The arithmetic unit 242, as will be described later, based on the falling edge signal of the rectangular wave signal TP _0, the encoder 2
10, the number of pulses of the input signal from the main controller 23 is counted.
It makes a comparison between _P (see FIG. 6), and outputs appropriate trigger signal TP ₁ to the laser controller 26 based on the comparison result.

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. Trigger circuit 262
Generates a trigger signal TP ₂ having a pulse width instructed from the main controller 23 to the central processing unit 261 in synchronization with the rise of the trigger signal TP ₁ from the trigger unit 24, and this trigger signal TP ₂ is transmitted to the switch unit 132. Is entered. The voltage value of the electric charge supplied to the capacitor unit 131 is input from the input / output unit 260 to the central processing unit 261, and is instructed from the central processing unit 261 to the stabilized power supply unit 130. Thereafter, the laser light oscillates according to the above-described process.

Returning to FIG. 2, the functions of the processing head 12 and the detection optical system 127 will be described. First, the pulse laser beam 100 oscillated from the laser head 11 is applied to the dichroic mirror 12
At 0, the direction is changed, and the light is condensed by the condenser lens 121 and irradiated onto the work 1. Further, the detection light 200 emitted from the detection light source 122 is converted into parallel light by the collimator lens 123, and the half mirror 124 and the dichroic mirror 1
The light passes through 20 and is focused on the work 1 (a position corresponding to the dam bar on the lead frame) by the condenser lens 121 with a minute spot. Here, the optical axes of the pulse laser beam 100 and the detection beam 200 are coincident, and the condensing positions on the work 1 are substantially the same.

The detection light 200 reflected on the surface of the work 1 is
After passing through the condenser lens 121, the dichroic mirror 120, and the half mirror 124, the photodetector 1 is
The information on the surface of the work 1 is detected as an electric signal. In the present embodiment, since a laser light source is used as the detection light source 122, the laser light can be narrowed down extremely by the collimator lens 123 and the condenser lens 121. When detecting information on the surface of the work 1, a rising edge of the signal is detected. (Response) is fast, and detection can be performed with high resolution.

The operation of the dam bar repair / cutting device having the above-described configuration will be described with reference to FIGS. Figure 5 is a diagram showing the detection light and the irradiation position of the laser beam and its movement locus for processing at the time of repairing cutting dam bars (until the output of the TP ₁₎ 6 signal processing of the detected by the detection light 200 signals It is a time chart. However, in FIG.
The axes are defined as shown in the figure.

Firstly, to move the workpiece 1 by the XY table 21, the axis of the machining head 12, i.e. the position of the optical axis of detection light 200, a constant velocity v in the positive direction of the X axis along the trajectory L ₁ shown in FIG. 5 To move. Locus L ₁ is a line had been previous dam bars are cut in the original cutting step are directed from point A to point B. Thereby, the condenser lens 1
Detection light 200 condensed into a minute spot 21 is moved on the locus L ₁ of the lead frame, the change of the detection signal detected by the photodetector 126 is higher output lead pin 4, in position 3a after dam bar cutting Output is low.

The detection signal from the photodetector 126 is input to the comparator 241 of the trigger unit 24, and is binarized by the processing shown in the time chart of FIG. However,
The horizontal axis in FIG. 6 indicates time, and the workpiece 1 is moved at a constant speed v.
The lead pin (web portion) 4, the uncut dam bar 3, and the dam bar position 3a after cutting are schematically shown as a time change when moved by. The detection signal input to the comparator 241 is inputted is binarized based on a predetermined threshold V _TH shown by thin lines in FIG. 6 square wave signal TP _0, and the the arithmetic unit 242.

[0033] The arithmetic unit 242, based on the falling edge of the rectangular wave signal TP _0, starts counting the number of pulses from the encoder 210. Fall of the square wave signal TP ₀ corresponds to the end surface after the dam bar cutting the lead frame (the beginning of the dam bar position 3a after cutting). If the falling edge of the square wave signal TP ₀ is input before the count of the number of pulses from the encoder 210 reaches the predetermined count N _P set in the main controller 23,
The counting of the number of pulses from the encoder 210 is reset to 0, and the counting of the number of pulses from the encoder 210 is started from 0 again. In this case, the laser controller 26
No signal waveform is output. On the other hand, as shown in FIG.
If the falling edge of the square wave signal TP ₀ is not input even when the count reaches the predetermined count N _P , the reset as described above is not performed at this timing, and the count is continued slightly further, and the number of pulses from the encoder 210 is counted. When becomes a predetermined N _P1 , a trigger signal TP ₁ is output to the laser controller 26.

[0034] That is, to see if properly dam bars are cut by the falling of the rectangular wave signal TP _0,
Pulse if the fall of the rectangular wave signal TP ₀ is input is regarded as dam bar in its position is normally cut to a cutting state of the next dam bar check before reaching the predetermined count number N _P If the count of the number is reset, and conversely, the falling edge of the square wave signal TP ₀ is not input even when the count reaches the predetermined count number N _P , it is regarded that the uncut dam bar 3 exists at that position, previous square wave signal TP count N _P1 trailing edge point with respect to the predetermined _0, and outputs a trigger signal TP ₁ for laser light irradiation at a position at a predetermined distance in other words. After all, counting the number of pulses from the encoder 210 by the calculation unit 242 means that the movement amount of the work 1 corresponding to the existing distance of the lead frame material along the locus L ₁ (the direction in which the dam bars are connected) is measured. Become.

Here, the above-mentioned count N _P is a count number substantially corresponding to the distance of the pitch of the lead pins 4 (lead pitch). Thus, the main controller 23 is set in advance so that the count number corresponds to a distance slightly longer than the actual lead pitch. Also, for N _P1 , the number of counts is such that the laser beam is applied to almost the center of the uncut dam bar 3.
It is set in the main controller 23 in advance based on the lead pitch. Note that the trigger signal TP ₁ in FIG. 6, but actually having a pulse waveform having a certain width, because very pulse width is shorter than the other signals, is shown in a line shape in the Figure .

[0036] Next, in the laser controller 26, the trigger signal TP ₁ is inputted to the trigger circuit 262, from the trigger circuit 262, the trigger signal TP ₂ in synchronization with the rising edge of the trigger signal TP ₁ is outputted (refer to FIG. 4 ). The pulse width of the trigger signal TP ₂ is indicated via the central processing unit 261 from the main controller 23 as described above. Moreover the trigger signal TP ₂ is input to the switch unit 132, the switch 132 becomes on in synchronization with the rising edge of the trigger signal TP _2, the charge from the capacitor 131 is supplied to the excitation lamp 110, further trigger signal TP ₂ In synchronization with the fall, the switch unit 132
ff, and the supply of charges to the excitation lamp 110 is stopped. Pulsed laser light is oscillated in synchronization with the trigger signal TP ₂ as described above.

FIG. 7 shows the operation section 24 of the trigger unit 24 when repairing and cutting the uncut dam bar as described above.
6 is a flowchart showing a process (trigger function) in No. 2; First, at a point A (see FIG. 5) at which movement starts, a trigger function, which is a series of functions from detection of the lead pin 4 to laser processing of the dam bar, is turned on (step S in FIG. 7).
1) The counting of the number of pulses from the encoder 210 is started from the point A (step S2). Then, to detect whether there is a falling edge of the rectangular wave signal TP ₀ before the count reaches a predetermined initial count number N ₀ (step S3), and the rectangular wave signal TP ₀ before the initial count number N ₀
If the fall of the judges that the first dam bar has been successfully cut, counting the number of pulses from the encoder 210 is reset to 0 at the fall timing of the rectangular wave signal TP _0, the encoder from 0 again The counting of the number of pulses from 210 is started (step S4). However,
The initial count number N ₀ is a value corresponding to the distance from the point A on the trajectory L ₁ to the end face that cuts the first dam bar, and N
Like _P , it is set in the main controller 23 in advance with a margin for accuracy.

On the other hand, in step S3, the initial count number N ₀
Of if the fall of the rectangular wave signal TP ₀ is detected before, the process proceeds to step S5, it is determined the first dam bar is uncut, a predetermined corresponding to the distance from the point A to the first dam bar cutting position now that a number of counts N _01,
And outputs a trigger signal TP ₁ to the laser controller 26. The count number _{N01 is} also determined in advance by the main controller 23.
Is set to Then, although resets the count of the number of pulses 0 at this timing, the count number in step S5 is advanced the distance on an amount corresponding locus L ₁ corresponding to the N ₀₁ -N ₀ = N _off, the N _off Is added to the count number from the encoder 210, and the counting is started again from this N _off instead of from 0. The distances corresponding to N ₀ and N ₀₁ are shown in FIG.

When the process for the first dam bar (detection of the uncut dam bar and its repair and cutting) is completed as described above, the process proceeds to step S6, and is arranged at a predetermined pitch as described with reference to FIGS. It detects whether the dam bar is normally cut or not cut, and performs control to oscillate laser light only when the dam bar is not cut. That is,
In step S6, the number of pulses from the encoder 210 is N
Fall of TP ₀ detects whether it has been entered prior to reaching the _P, the process proceeds to step S7 if the fall of the TP ₀ before the N _P is not input, the falling of the TP ₀ before the N _P If a down is input, the process proceeds to step S8. In step S7, and outputs a trigger signal TP ₁ from the fall of the TP ₀ at the timing of the N _P1, and start the reset counts again counting the number of pulses at that timing, the same operation is repeated returning the step S6. However, as in step S5 described above, in step S7, the trajectory L ₁ corresponds to the count number corresponding to N _P1 −N _P = N _off.
Since the upper distance is advanced, counting is started from N _off . Here, for simplicity, N _P1 −N _P = N ₀₁ −N ₀
= N _off .

The sum of the falling number and laser light irradiation number in step S8 in TP ₀ (repair disconnection count) detects whether reaches the predetermined value M, the entire trajectory L ₁ if it has not reached the M it is determined that processing has not yet been returned to step S4, and repeats the operation from the fall detection of TP _0. The total fall times and laser light irradiation number of TP ₀ in step S8 if they reached the M is assumed that processing of the entire locus L ₁ is completed, the trigger function to off (the step S9). Here, the predetermined value M corresponds to the total number of dam bars on _one side (trajectory L ₁ ) of the work 1 and is set in the main controller 23. Repair cleavage of dam bar 3 detection and uncut along the locus L ₁ above is automatically performed.

In the above description, the detection along the trajectory L ₁ corresponding to one side of FIG. 5 and the repair cutting of the uncut dam bar 3 have been mainly described, but the trajectory L 1 corresponding to the other side is described.
Even if there is dam bars uncut in any position in the ₂ ~L _4, can be automatically repaired cutting dam bars of all uncut by the same procedure.

According to the present embodiment as described above, using the detection light 200, the existing distance of the material of the lead pin 4 along the trajectories L _{1 to} L ₄ (information of the lead frame shape after dam bar cutting) is detected. Then, based on the detected result, the uncut dam bar 3 is detected, and based on the detection result, the oscillation of the laser beam 100 is controlled to irradiate the uncut dam bar 3 with the laser beam. Uncut dam bar 3
Can be repaired and cut reliably and accurately. Therefore, even when the reproducibility of the lead frame shape and the reproducibility of the lead frame fixing position are low, the uncut dam bar at the desired position to be cut is cut accurately, reliably and at high speed, and the lead pin which should not be processed. Is not processed.

Even if the type of the lead frame changes, the uncut dam bar 3 can be repaired and cut based on the information of the target individual lead frame shape, so that the position of the uncut dam bar position corresponding to the type of the lead frame can be changed. The troublesome work such as the measurement work and the editing of the program necessary for repair cutting is not required, and the uncut dam bar 3 in various types of lead frames can be repaired and cut by a simple procedure.

In the above description, it is assumed that the regular dam bar cutting step is performed using a mold and a press machine, but the regular dam bar cutting step itself can be performed by laser beam irradiation. The present invention can be applied after such a regular dam bar cutting step by laser beam irradiation.

[0045]

According to the present invention, the existing distance of the lead frame material (information on the shape of the lead frame after dam bar cutting) along the direction in which the dam bars are connected is detected, and the uncut dam bar is detected based on the detected distance. Then, since the oscillation of the laser beam is controlled based on the detection result, the uncut dam bar can be repaired and cut reliably and accurately. Therefore,
Even when the reproducibility of the lead frame shape and the reproducibility of the lead frame fixing position are low, the uncut dam bar at the desired position to be cut can be cut accurately, reliably and at high speed, and should not be processed. The lead pins are not processed.

Further, even if the type of the lead frame is changed, a troublesome operation such as a work of measuring an uncut dam bar position according to the type of the lead frame and editing of a program required for repair cutting is not required, and the simple operation is simplified. It is also possible to repair and cut uncut dam bars in various types of lead frames by the procedure.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of a dam bar repair / cutting device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a configuration of a processing head and a detection optical system of FIG. 1;

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 diagram showing irradiation positions of detection light and processing laser light when the dam bar is repaired and cut, and the movement locus thereof.

FIG. 6 shows a signal processing (TP _{1) of} a signal detected by the detection light.
3) is a time chart.

FIG. 7 is a flowchart showing a process (trigger function) in a calculation unit of the trigger unit when repairing and cutting an uncut dam bar.

FIG. 8 is a view for explaining a conventional general dam bar cutting using a mold having a comb-shaped press blade.

FIG. 9 is a view for explaining a case where the shape of the end surface obtained by cutting the dam bar by the press blade is not symmetric.

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

11A is a simplified plan view showing an IC package, and FIG. 11B is an enlarged view of a portion B in FIG. 11A and is an uncut dam bar after the dam bar is cut by the press blade in FIG. FIG.

[Explanation of symbols]

 Reference Signs List 1 work (IC package) 2 dam bar 3 uncut dam bar 4 lead pin (web part) 5 resin mold part 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 Reference Signs List 26 laser controller 100 laser beam 110 excitation lamp 120 dichroic mirror 121 condenser lens 122 detection light source 123 collimator lens 124 half mirror 125 imaging lens 126 photodetector 127 detection optical system 130 stabilizing power supply section 131 capacitor section 132 switch section 133 AC Power supply unit 200 Detection light 210 Encoder 241 Comparator 242 Operation unit 260 Input / output unit 261 Central operation unit 262 Trigger circuit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shigeyuki Sakurai 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant (72) Inventor Yasushi Minomoto 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Inside Engineering Co., Ltd.

Claims (2)

[Claims] 1. A dam bar repair cutting method for repairing an uncut dam bar after a dam bar cutting step of a semiconductor device in which a semiconductor chip and a lead frame are sealed with resin by irradiating a pulsed laser beam. Moving the semiconductor device in a direction continuous with the dam bar while irradiating the position after the dam bar cutting with the detection light, generating a detection signal based on reflected light of the detection light from the lead frame; Measuring the movement amount of the semiconductor device corresponding to the existing distance of the lead frame material at the detection position by the detection light, and the measured movement amount of the semiconductor device and the dam bar are normally cut. The value corresponding to the existing distance of the lead frame material when the When the momentum is larger than the value corresponding to the existing distance of the lead frame material when the dam bar is normally cut, it is determined that the uncut dam bar exists at the detection position by the detection light, and the uncut And controlling the oscillation of the laser beam so that the laser beam is applied to the dam bar. 2. A laser oscillator that oscillates pulsed laser light, a processing optical system that guides the laser light to a workpiece, and a transport unit that moves the workpiece and determines a processing position thereof. A semiconductor device in which a semiconductor chip and a lead frame are sealed with a resin, in a dam bar repair cutting device for repairing and cutting an uncut dam bar after a dam bar cutting step, wherein a detection light is applied to a position of the lead frame after the dam bar cutting. Detecting light generating means for irradiating; detecting means for irradiating reflected light of the detection light from the lead frame to generate a detection signal according to the detection result; and detecting the detection based on the detection signal from the detection means. Measuring means for measuring an amount of movement of the transport means corresponding to a distance of the lead frame material at a detection position by means, and measuring by the measuring means Comparing means for comparing the distance moved and a value corresponding to the existing distance of the lead frame material when the dam bar is normally cut, and measuring by the measuring means based on the comparison by the comparing means If the moved amount is larger than the value corresponding to the existing distance of the lead frame material when the dam bar is normally cut, it is determined that there is an uncut dam bar at the detection position by the detection means, and the Control means for controlling the oscillation of the laser light so that the uncut dam bar is irradiated with the laser light.