JP3388461B2 - Laser bonding method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser bonding method and apparatus, and more particularly to a laser bonding method for performing laser bonding between a redundant circuit provided for repairing a defective wiring broken in a liquid crystal panel or the like and a defective wiring. And equipment.

[0002]

2. Description of the Related Art In a conventional laser joining method of this type, for example, as shown in Japanese Unexamined Patent Publication No. 10-319438, laser joining is performed between a broken defective wiring such as a liquid crystal panel and a redundant circuit. Is used for. FIG. 4 is a plan view showing an example of the liquid crystal panel. In the liquid crystal panel,
As shown in FIG. 4, a redundant circuit 5 is provided under the signal wiring 4 in advance. If the signal wiring 4 has a disconnection portion 6, a laser spot irradiation is performed from above the signal wiring 4 to the overlapping portion 7 where the redundant circuit 5 and the signal wiring 4 remaining without disconnection overlap. The disconnection of the signal wiring 4 is corrected by welding and electrically connecting the signal wiring 5 and the signal wiring 4.

In the conventional laser joining method, in the laser joining of the redundant circuit of the liquid crystal panel, the technique of irradiating only one shot with the pulse laser has been mainly used.

[0004]

However, since the laser bonding is a thermal process, thermal deformation and thermal deterioration around the bonded part or the upper and lower films are unavoidable. Energy input is most ideal. Therefore, due to factors that are not considered when calculating
When the calculated laser output is actually too large, the method of irradiating only one shot cannot judge the processing state and stop the processing with a laser output lower than the calculated laser output when necessary.

According to the present invention, the laser energy is subdivided into a plurality of pulse shots, and the laser irradiation is stopped when necessary by judging from the processing state, so that the processing can be stopped with the minimum required laser output. An object of the present invention is to provide a laser bonding method and device capable of quickly completing laser bonding while minimizing deformation and deterioration of the peripheral portion and upper and lower films due to laser heat input.

[0006]

In the laser bonding method of the present invention, the total energy of pulse irradiation of a predetermined number of times performed on an overlapping portion of a plurality of electrode patterns arranged so as to overlap each other inside a substrate is determined. , so that the energy which is expected to be required for joining by melting a plurality of electrode patterns, and, since the number of times said predetermined, pre
The minimum energy that is the energy of whether or not melting progresses
Laser energy value (hereinafter called threshold value)
The energy of each pulse irradiation according to the number of times of irradiation is specified so that laser light is pulse-irradiated to the part to be bonded with the specified energy, and the bonding state of the irradiation part from the side opposite to the irradiation after each pulse irradiation. Is observed to detect whether or not they have been joined. When they are not joined, pulse irradiation with an energy specified according to the number of irradiations is performed, and when they are joined, pulse irradiation is stopped.

According to the present invention, the total energy of the pulse irradiation of a predetermined number of times is the energy expected to be required for melting and bonding the plurality of electrode patterns, and After a predetermined number of times, by prescribing the energy of each pulse irradiation according to the number of times of irradiation so as to have a threshold value that is the energy of whether or not the melting proceeds , the heat storage at the end of bonding This can be reduced to prevent thermal deterioration and deformation around the joint portion, and the energy value of each pulse shot is defined to be high up to a predetermined number of irradiations, so that the joining can be completed quickly.

Further, in the above invention, after each pulse irradiation, before deciding the joining state of the irradiation section from the side opposite to the irradiation side, whether the joining state of the irradiation section is observed from the irradiation side to perform the joining. If it is determined that the bonding has been performed as viewed from the irradiation side, and if the bonding has not been performed as viewed from the side opposite to the irradiation, pulse irradiation with the threshold value is performed regardless of the number of irradiations.

According to the present invention, even if the energy required for bonding is lower than expected, the energy of the pulsed laser beam can be reduced before the completion of the bonding, and the time when the bonding is completely completed. The amount of heat stored in can be reduced.

In the above invention, the total energy of pulse irradiation is calculated until the joining is completed, and each pulse is adjusted so that the total energy of pulse irradiation of a predetermined number of times becomes the total energy. Calibrate the regulation of irradiation energy.

According to the present invention, the regulation of the energy is calibrated from the total energy of the pulsed laser light, so that, for example, when the same liquid crystal panel is joined at another location,
There is a high possibility that the joining will be terminated by the final pulse shot, and when the energy required for the joining is larger than expected, it is possible to prevent the pulse laser light from being continuously irradiated with the threshold value and to complete the joining promptly. Also, when the energy required for bonding is less than expected, the energy of the pulsed laser light immediately before the completion of bonding is prevented from increasing and the amount of heat stored at the time of completion of bonding is prevented from increasing, and thermal deterioration and deformation around the joint are not caused. You can

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the laser bonding apparatus of the present invention.

The liquid crystal panel 1 to be laser-bonded is
It is held and fixed on the liquid crystal panel stage 3 on the XY stage 2. As shown in FIG. 4, the liquid crystal panel 1 is provided with a redundant circuit 5 overlapping each signal wiring 4, and the signal wiring is overlapped with both of the separated portions 6 due to the disconnection of the signal wiring. One or more joining positions are set for each overlapping portion 7, laser joining is performed at the positions, and disconnection of the signal wiring is repaired.

The control unit 8 moves the XY stage 2,
The liquid crystal panel 1 is positioned so that the laser beam is irradiated to the laser bonding position set in the overlapping amount area of the signal wiring 4 and the redundant circuit 5.

The pulsed laser light emitted from the laser oscillator 9 passes through the lens 10, the optical slit 11 and the lens 12, then passes through the optical mirror 13 and the optical lens 14 for condensing the pulsed laser light, and then the liquid crystal panel. An image is formed at the laser bonding position 1.

An image from around the processing mark and the upper surface of the upper and lower wiring layer films when the laser beam is irradiated is transmitted through the optical lens 14, the optical mirrors 13 and 15, and the optical lens 16 to the camera 1.
Caught in 7. The illuminator 18 for capturing the image of the camera 17
Thus, the upper surface of the liquid crystal panel 1 is illuminated. Camera 1
The image information from 7 is input to the junction detector 19 and the junction detector 19 determines whether or not the redundant circuit has passed through, and the determination result is output to the control unit 8 one by one. Similarly, images from the periphery of the processing mark and the lower surface of the upper and lower wiring layer films are displayed by the optical lens 20,
It is captured by the camera 23 via the optical mirror 21 and the optical lens 22. The lower surface of the liquid crystal panel 1 is illuminated by the illuminator 24 for the image pickup by the camera 23. The image information from the camera 23 is input to the junction detector 25, the junction detector 25 determines whether the redundant circuit 5 has penetrated, and the determination result is output to the control unit 8.

As the pulsed laser light is continuously irradiated at a predetermined time interval, the joint portion of the redundant circuit 5 irradiated with the pulsed laser light is melted and the melted portion is gradually spread to the periphery and the through hole is formed. It is formed. At this time, the melting of the pattern on the opposite side progresses later than the irradiation side. Therefore, when it is detected from the camera 17 on the irradiation side that the processing mark has reached a sufficient size, it is delayed from the camera 23 on the opposite side. It is detected that the processing mark has reached a sufficient size, and the joining is detected.

The laser controller 26 controls the timing of outputting the pulsed laser light from the laser oscillator 9 and the energy value of each pulsed laser light based on a command from the control unit 8. Also, an energy change function that gives the absolute energy value of the pulsed laser light is set in advance using the number of shots as a parameter. Further, the laser controller 26 is an energy value indicating whether or not the fusion of the joint portion of the redundant circuit 5 proceeds after the joint detector 19 detects the joint between the signal wiring 4 and the redundant circuit 5.
The minimum laser energy value (threshold value) is stored. The energy value of each pulsed laser beam is controlled based on these.

FIG. 2 is a diagram showing an example of a change in laser energy of the laser oscillator 9 based on a command from the laser controller 26 of FIG. The change in the laser energy of each pulse shot that is sequentially irradiated to the junction decreases rapidly as the final pulse shot that completes the irradiation of the energy expected for the junction is approached, and the energy value of the final pulse shot Is described as an exponential function so as to have a threshold value that is an energy value of whether or not laser bonding processing is performed. Further, the number of pulse shots irradiated until the irradiation of the energy expected to be required for the bonding is finished is set to 15, and the energy change is set so as to affect the threshold value immediately after the final pulse shot. If the number of pulse shots is increased, it takes a longer processing time, and if the number of pulse shots is decreased, the energy per pulse becomes large, and excess energy may be added beyond the minimum energy required to advance the bonding. It is desirable to set the number of pulse shots applied until the irradiation of the energy expected to be performed until the irradiation is finished, for example, from 10 to 20.

The first shot is set to a relative value of 100%, and the threshold value corresponds to 40%. This setting has a similar meaning to the setting of the number of pulse shots, and if the energy of the first shot is close to the threshold value, the number of shots will increase and processing time will be required. Further, if the energy of the first shot is made larger than the threshold value, the energy per pulse becomes large, so energy much larger than the minimum energy required for advancing the junction is added and excess heat is accumulated. May increase. Relative value 10 for the first shot
It is desirable to set the threshold value to 0% so that the threshold value corresponds to 30 to 50%.

Next, the operation of laser joining according to this embodiment will be described.

FIG. 3 is a flow chart showing the operation of the laser bonding shown in FIG.

First, an energy change function that determines the energy value of the pulsed laser light in each shot according to the number of shots of the pulsed laser light, and a threshold value that is an energy value of whether or not laser joining processing is performed. Is preset (step S1). Further, all the laser bonding positions of the liquid crystal panel set on the stage 3 are input. Then, the XY stage 2 is moved to align the laser irradiation position with the first laser joining position (step S2).

When the joining is started, the shot number N is set to 1 (step S3), the energy value corresponding to the shot number N is calculated based on the energy change function (step S4), and the calculated energy is calculated. The pulsed laser light having a value is applied to the laser bonding portion of the liquid crystal panel 1 (step S5). When the calculated energy value becomes less than or equal to the threshold value, the energy value of the pulsed laser light is set as the threshold value. In addition, when N is 2 or more, from the irradiation of the previous pulse laser light, that is, the pulse laser light of the (N-1) th shot,
The pulsed laser light is emitted at a timing when a preset time has elapsed.

After the pulse laser irradiation, first, image information of the spot-shaped pulse laser light irradiation portion is input from the laser irradiation surface side camera 17 to the joint detector 19, and the joint detector 19 is connected.
Then, the size of the processing mark of the spot-shaped pulsed laser light irradiation site is compared with the reference value A, and it is determined whether or not they are bonded (step S6). If they are not joined, the number of shots N is incremented (step S7) and the process returns to step S4.

When the joining is determined in step S6, the image information of the spot-shaped pulsed laser light irradiation portion imaged by the camera 23 on the side opposite to the laser irradiation side is input to the joining detector 25, and the joining detector 25 then. The processing mark size of the spot-shaped pulsed laser light irradiation site is compared with the reference value B, and it is determined whether or not they are joined (step S8). After the pulse laser irradiation, if not bonded, pulse laser light having a threshold value is applied to the laser bonding position of the liquid crystal panel 1 (step S9), and the bonding is further advanced. This threshold value is an energy value of whether or not the bonding is processed, and even if there is an error of ± several shots, thermal deformation and deterioration are unlikely to occur. After irradiation, the process returns to step S8. When it is determined in step S8 that the laser beam has penetrated, the laser bonding of that portion is completed, and the total energy irradiated until the laser beam is bonded is calculated, and the energy is adjusted so that it is just below the threshold value with the preset number of shots. The change function is calibrated (step S10), and the calibrated energy change function is used for the joining at the next joining position.

To calibrate this energy change function, first, the total energy of each pulsed laser beam until it is determined that the beam has penetrated is calculated, and after it is determined that the beam has penetrated in step S6, irradiation is performed with a threshold value. Step S
The sum of the energies of the pulsed laser light irradiated until it is determined that the laser beam has penetrated in 8 is added to calculate the sum of the energies required for bonding. Then, an energy change function is obtained in which the threshold value is obtained with a preset number of shots and the total energy of the pulsed laser light irradiated until reaching the threshold value is the junction energy.

Then, it is judged whether the position is the last laser bonding position (step S11), and if it is not the last position, the XY stage 2 is moved so that the laser irradiation position matches the next laser bonding position (step S12). If it is the last laser bonding position in step S11, the laser bonding operation is terminated.

Next, a modification of the above embodiment will be described.

Since the joining process by laser heat input is a repeating heating process and cooling process, the cooling phenomenon of the previous pulse shot overlaps the heating phenomenon of the next pulse, and this overlap affects the joining quality. . In this modification, the energy change function is changed in accordance with the set time interval in consideration of the influence on the joint quality due to the fact that the cooling phenomenon of the previous pulse shot overlaps the heating phenomenon of the next pulse. That is, the energy change function of FIG. 2 is a function having two variables, the number of shots N and the time interval t of the pulsed laser light.

As a result, it is possible to minimize the damage around the junction regardless of the setting of the time interval for irradiating the pulsed laser beam.

Further, instead of setting the energy value according to the number of shots, a time interval change curve defining the pulse laser light irradiation time interval is set to change the pulse laser light irradiation time interval. Good. In addition to setting the energy value according to the number of shots, a time interval change curve defining the pulse laser light irradiation time interval may be set.

By this, it is possible to prevent the energy of each pulsed laser beam from being set to an excessively large or small laser energy, and it is possible to carry out bonding with an appropriate output of the laser oscillator to be used, and to stably enter the laser energy. You can control the heat.

[0035]

As described above, according to the laser bonding apparatus of the present invention, it is expected that the total energy of pulse irradiation of a predetermined number of times is required to melt and bond a plurality of electrode patterns. The energy of each pulse irradiation according to the number of times of irradiation should be specified so that the energy becomes a certain energy, and after the predetermined number of times, the threshold value that is the energy of whether or not melting progresses is reached. By this, it is possible to reduce the heat storage at the end of joining so as not to cause thermal alteration and deformation around the joining portion, and to specify a high energy value for each pulse shot up to a predetermined irradiation number. Therefore, the joining can be completed promptly.

Further, when the joining state on the irradiation side and the side opposite to the irradiation are monitored and it is judged that they are joined as viewed from the irradiation side, and when they are not joined as viewed from the side opposite to the irradiation, regardless of the number of times of irradiation. Perform pulse irradiation with the threshold value .

According to the present invention, even when the energy required for bonding is lower than expected, the energy of the pulsed laser beam can be reduced before the completion of the bonding, and the time when the bonding is completely completed. The amount of heat stored in can be reduced.

Further, the total energy of pulse irradiation is calculated until the joining is completed, and the regulation of energy of each pulse irradiation is calibrated so that the total energy of pulse irradiation of a predetermined number of times becomes the total energy. To do.

According to the present invention, the regulation of the energy is calibrated from the total energy of the pulsed laser light, so that, for example, when the same liquid crystal panel is joined at another location,
There is a high possibility that the joining will be terminated by the final pulse shot, and when the energy required for the joining is larger than expected, it is possible to prevent the pulse laser light from being continuously irradiated with the threshold value and to complete the joining promptly. Also, when the energy required for bonding is less than expected, the energy of the pulsed laser light immediately before the completion of bonding is prevented from increasing and the amount of heat stored at the time of completion of bonding is prevented from increasing, and thermal deterioration and deformation around the joint are not caused. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a laser bonding apparatus of the present invention.

FIG. 2 is a diagram showing an example of changes in laser energy of the laser oscillator 9 of FIG.

FIG. 3 is a flowchart showing an operation of laser joining in FIG.

FIG. 4 is a plan view showing an example of a conventional liquid crystal panel.

[Explanation of symbols]

1 LCD panel 2 XY stage 4 signal wiring 5 Redundant circuit 6 overlapping parts 7 disconnection 8 control unit 9 Laser oscillator 10, 12, 14, 16, 20, 22 lens 11 Optical slit 13,15,21 optical mirror 17,23 cameras 18, 24 Illuminator 19, 25 junction detector 26 Laser controller

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // B23K 101: 40 B23K 101: 40 (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 26/00-26 / 40 G02F 1 / 13,1 / 1343

Claims (8)

(57) [Claims] 1. Pulse irradiation of laser light performed a plurality of times for overlapping portions of a plurality of electrode patterns arranged so as to overlap each other inside a substrate, the pulse irradiation being performed a predetermined number of times.
So that the sum of the energies of the electrodes is the energy expected to be required for melting and joining the plurality of electrode patterns, and after the final pulse irradiation of the pulse irradiation of the predetermined number of times, the melting is performed. Whether or not
Of defining the energy of each pulse irradiation according to the number of times of irradiation such that the energy value, the laser beam pulses irradiating the portion to be joined in a defined energy in accordance with the number of times of irradiation, the laser beam after each pulse irradiation Opposite to the side that is irradiated
The irradiation state of the irradiation part is observed from the side to detect whether or not it has been bonded.When not bonded, pulse irradiation of energy specified according to the number of irradiation is performed, and when bonding is stopped, pulse irradiation is stopped. A laser bonding method comprising: 2. The laser light after each pulse irradiation
Before observing the joint state of the irradiation part from the side opposite to the side irradiated with, the joint state of the irradiation part is observed from the irradiation side to detect whether or not the joint has been made, and the joint side is seen from the irradiation side. When it is detected and it is detected that it is not joined when viewed from the side opposite to the irradiation, the energy of whether or not the melting proceeds regardless of the number of times of irradiation
2. The laser bonding method according to claim 1, wherein the pulse irradiation of a predetermined value is performed. 3. The energy of each pulse irradiation is rapidly reduced as the final pulse irradiation is approached, and the energy of the final pulse irradiation is whether or not the bonding progresses.
2. The laser bonding method according to claim 1, wherein an energy defining function that defines the energy value of each pulse irradiation is set so as to obtain the energy value. 4. The energy of each pulse irradiation is calculated so that the total energy of pulse irradiation is calculated until the joining is completed, and the total energy of pulse irradiation of a predetermined number of times becomes the total energy. The laser joining method according to claim 1, wherein the laser is calibrated. 5. The laser bonding method according to claim 3, wherein the energy defining function is an exponential function. 6. The laser bonding method according to claim 3, wherein the pulse irradiation is performed at preset time intervals, and the energy defining function is set based on the time intervals. 7. A laser irradiation unit for emitting a pulsed laser beam and a substrate having a plurality of electrode patterns to be joined, which are overlapped with each other, are held, and the pulsed laser beam is provided at an overlapping portion of the plurality of electrode patterns. Of the substrate moving unit that moves so as to match the irradiation position of the substrate, and the bonding state of the irradiation unit of the pulsed laser light is observed from the side opposite to the side of the substrate irradiated with the pulsed laser light to detect whether or not bonding has been performed. The detector and the total energy of the pulse irradiation energy from the first pulse irradiation is the energy expected to be required for the bonding, and the energy of each pulse irradiation is rapidly reduced as the final pulse irradiation is approached. Joining progresses
The energy value of each pulse irradiation is specified in advance to the energy value of whether or not , based on the detection result obtained from the detection unit after each pulse irradiation, when not bonded, it was specified according to the number of times of irradiation. A laser bonding apparatus, comprising: a control unit that causes the laser irradiation unit to perform pulse irradiation of energy and stops the pulse irradiation of the laser irradiation unit when bonding is performed. 8. An irradiation side detection unit for observing a bonding state from an irradiation side of the substrate irradiated with the pulsed laser light to detect whether or not bonding is performed, and the control unit includes the irradiation side detection unit. When it is detected that the part is not bonded, the laser irradiation part is caused to perform pulse irradiation of energy specified according to the number of irradiations, the irradiation side detection part detects the bonding, and the detection part When it is detected that they have not been joined, the laser irradiation unit is caused to perform pulse irradiation at an energy value indicating whether or not the bonding proceeds regardless of the number of irradiations, and the irradiation side detection unit and the detection unit perform the bonding. When it is detected that
The laser bonding apparatus according to claim 7, wherein pulse irradiation of the laser irradiation unit is stopped.