JPH0373395B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a laser trimming device used for manufacturing thick film modules such as VTRs. [Background of the Invention] As shown in Fig. 1, a conventional laser trimming device of this type has a Q switch 2 built into a resonator.
A pulsed laser beam 3 output from a YAG laser oscillator 1 (hereinafter referred to as an oscillator) is transmitted to a mirror 4.
after being reflected by the optical scanner 5. The optical scanner 5 focuses the laser beam 3 onto a minute spot, and two-dimensionally scans and positions the resistor 6 provided on the substrate 7. A test signal 9 from an electric circuit including this resistor 6 is measured by a measurement/control unit 8, and control signals 10, 11 are output from the measurement/control unit 8 based on the measurement results. One control signal 10 operates the optical scanner 5 to control the scanning and positioning of the laser beam 3, and the other control signal 11 operates the Q switch 2 of the oscillator 1 to control the on/off of the laser beam 3. conduct. A time chart during trimming in the conventional laser trimming device having the above configuration will be described in detail with reference to FIG. To start trimming of adjustment item _A1 , first set the conditions (a), send the power supply voltage, test signal, and various circuit control signals from the measurement/control unit 8 to the electric circuit on the board 7, and then Adjust the item
A Make the operating state in accordance with the adjustment specifications in ₁ . During the next circuit stabilization time (hereinafter referred to as stabilization time) (b), the disturbance in the electrical circuit that has entered a transient state due to the application of the various signals in condition setting (a) subsides, and the test signal 9 becomes measurable. Wait until the condition is reached. Then, at measurement time (c), the measurement/control unit 8 measures the test signal 9. In the calculation time (d), the measurement/control unit 8 performs predetermined arithmetic processing on the measurement results of the inspection signal 9, and in the next operation time (e), the laser beam 3
In addition to determining the coordinates of the starting point and ending point on the resistor 6, the scanning speed, and the pulse oscillation frequency of the laser beam 3 necessary for scanning, the measurement/control unit 8 also controls the coordinates of the starting point and ending point and the scanning speed. The information is transmitted to the optical scanner 5 via the control signal 10, and the optical scanner 5 is operated to scan the laser beam 3 from the starting point to the ending point. At the same time, the pulse oscillation frequency of the laser beam 3 and the pulse oscillation on/off control information are
transmitted to the Q switch 2 via the control signal 11,
The Q switch 2 is operated to oscillate and output the laser beam 3 while moving from the starting point to the ending point, thereby removing a portion of the resistor 6. As a result, the resistance value of the resistor 6 increases and the value of the test signal 9 changes indirectly, so the measurement time (c)
Repeat the order of calculation time (d) and operation time (e) several times to gradually bring the value of inspection signal 9 closer to the target value, and confirm that this value has reached the target value at the last measurement time (c). Then, trimming for that adjustment item is finished.
In the case of adjustment item A ₁ , the order of measurement time (c), calculation time (d), and operation time (e) is changed to 3 after stability time (b).
Repeat several times, and finally end at the measurement time (c). Next, condition setting (a) for adjustment item A ₂ is started, and thereafter trimming proceeds in the same procedure as adjustment item A ₁ . The trimming time for adjustment item _A1 was about 8 seconds, and for adjustment item _A2 it took 5 to 10 seconds. In addition, the operation time (e) of A ₂ above is only 7 to 8% of the entire adjustment item A ₁ , and on the contrary, the stability time (b)
is as large as 28%. Adjustment item A Stability time after ₂ (b)
In some cases, it reached up to 50%. Furthermore, the measurement time (c) after adjustment item _A2 includes the time to wait until the disturbance in the inspection signal 9 due to trimming subsides, so the trimming time for functional trimming is shorter than that for simple resistance trimming. Since it is more than 10 times longer and the ratio of stability time (b) and hidden stability time is large, there was a risk that the trimming processing capacity would be reduced. [Object of the Invention] In view of the above, an object of the present invention is to provide a laser trimming device with improved trimming processing capacity at a price comparable to that of conventional devices, that is, a laser trimming device with good cost performance. be. [Summary of the Invention] In order to achieve the above object, the present invention splits a laser beam from a laser oscillator with a built-in Q switch using a beam splitter, and divides the laser beam into each optical path of the divided laser beam. An optical shutter that performs shedding and passage control, an optical scanner that focuses laser light onto a minute spot and scans the workpiece, and a substrate on which the workpiece is mounted are sequentially arranged, and the A measurement/control unit is provided to input inspection signals from the electrical circuit including the workpiece, and this measurement,
By each control signal output from the control section, the Q
The present invention is characterized in that the workpieces are trimmed alternately or simultaneously by controlling a switch, each optical shutter, and each optical scanner. [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a configuration diagram of this embodiment, in which the YAG laser oscillator 1 (hereinafter referred to as the oscillator) is connected to the Q switch 2.
is built into the resonator and outputs a pulsed laser beam 3. This laser beam 3 is transmitted to a beam splitter 4
One of the laser beams 3a is reflected by a mirror 4b and passed through the optical shutter 4b.
Input to a and 5b. This optical scanner 5a, 5
b focuses the laser beams 3a and 3b onto a minute spot, and scans and positions the low antibodies 6a and 6b placed on the upper surfaces of the substrates 7a and 7b in two dimensions, respectively. The measurement/control unit 8 measures test signals 9a and 9b from each electric circuit including the resistors 6a and 6b, and generates a control signal 1 based on these measurement results.
0a, 10b, and these control signals 10
The optical scanners 5a and 5b are operated by the optical scanners 5a and 10b, respectively, and the scanning and positioning of these optical scanners 5a and 5b are controlled, respectively. At the same time, optical shutters 12a and 1 are activated by control signals 10a and 10b.
2b to control passage and cutoff of the laser beams 3a and 3b, respectively, and operate the Q switch 2 in accordance with the control signal 11 to control on/off of the laser beam 3. As shown in FIG. 4, the optical shutters 12a and 12b include a scanner body 30, a scanner case 30a containing the scanner body 30, an aluminum mirror 50, a sensor 62 having an output terminal 63, and the mirror 50 and the scanner case 30a. The cover 60 is made of aluminum and covers the sensor 62.
The inner surface of 0 is dyed black. The sensor 62 is fixed inside the cover 60. The scanner main body 30 is composed of a movable piece 32 integrally connected to a rotating shaft 31, yokes 33, 35 and magnets 34, 36 arranged to surround the movable piece 32 in a circular shape. As shown in FIG. 5, coils 37 and 38 are wound around the coils 33 and 35, respectively. York 3
3, 35 are magnetic poles 33a, 33b and 35a, 3
5b, which face the movable iron piece 32 and form a narrow gap. Lines of magnetic force 3 of the magnet 34
9 passes through the gap, the yoke 33 and the magnetic pole 33
a, a magnetic path is formed that sequentially connects the movable piece 32, the magnetic pole 3b, the yoke 35, and the magnet 34, and similarly, the magnetic field lines 40 of the magnet 36 connect the yoke 33, the magnetic pole 33b, the movable piece 32, the magnetic pole 35a, and the magnet 36
form a magnetic path that sequentially connects the On the other hand, magnetic lines of force 41 generated by the coil 37
forms a magnetic path that sequentially connects the yoke 33, the magnetic pole 33b, the movable iron piece 32, and the magnetic pole 33a, and the magnetic field lines 42 generated by the coil 38 connect the yoke 35, the magnetic pole 35a, the movable iron piece 32, and the magnetic pole 35.
Form a magnetic path connecting b. Coils 37, 38
When the current i is not applied to the magnetic field lines 41, 4
2 does not occur, the movable iron piece 32 follows the magnetic field lines 3
9 and 40, they are equally attracted to the magnetic poles 33a and 33b and the magnetic poles 35a and 35b, respectively, to establish a dynamically stable position. When current i is applied to the coils 37 and 38,
Magnetic lines of force 41 and 42 are generated, respectively, and the magnetic pole 33a
At the magnetic pole 33b, the lines of magnetic force 39 and 41 are in opposite directions, weakening the attraction force with the movable iron piece 32, and conversely, at the magnetic pole 33b, the lines of magnetic force 40, 41 are in the same direction, strengthening the attraction force with the movable iron piece 32. In the same manner as above, the magnetic pole 35a
Then, the attraction force with the movable iron piece 32 is weakened, and the magnetic pole 35b
Then, the suction force with the movable iron piece 32 is strengthened. Therefore, the movable iron piece 32 rotates in the direction of arrow K, and the movable iron piece 32 rotates in the direction of arrow K.
2 and each of the magnetic poles 33a, 33b, 35a, and 35b are at rest at a rotational position where the attractive forces are balanced. An input terminal 43 for a rotary shaft drive signal that connects one end of the rotary shaft 31 of the scanner main body 30 and the coils 37, 38 is led out through the scanner case 30a. When a DC voltage (+5 to -5V) is applied to the input terminal 43, the rotating shaft 31 moves from the neutral position at an angle (+15 to -5V) proportional to the voltage value.
It is set to rotate by 15°). The mirror 50 is formed in a cylindrical shape, and is provided with a laser beam reflecting surface 52 (hereinafter referred to as a reflecting surface) which is a plane including the center line of rotation and has a satin finish on its upper part, and has a set screw 51. It is fixed to the rotating shaft 31 via the rotary shaft 31. When the voltage applied to the input terminal 43 is zero V, the reflective surface 52
As shown by the solid line in the figure, it is at a rotational position that cuts the optical path of the laser beam, so the laser beam 3 that has passed through the opening 61 provided in the cover 60 is reflected by the reflective surface 52 and becomes laser beam 3R. It is input to a laser light detection sensor 62 (hereinafter referred to as a sensor). When the laser beam 3R is input to the sensor 62 in this manner, a current output is obtained at the output terminal 63 for laser beam detection. On the other hand, the voltage applied to the input terminal 43 is +5V.
At this time, the reflective surface 52 is at a rotational position parallel to the laser beam optical path as shown by the broken line in FIG.
passes through the side of the reflective surface 52 and exits from the opening 64 as a laser beam 3P. Therefore, since the sensor 62 cannot detect the laser beam 3P, no current output can be obtained at the output terminal 63. FIG. 6 is an explanatory diagram of the driver for driving the optical shutters 12a and 12b, and the control section 70 in this figure includes a drive amplifier for the scanner main body 30 and a detection amplifier for the sensor 62 (both not shown). The shutter signal 71 is transmitted to the input terminal 43 of the scanner main body via the drive amplifier, and the current output of the output terminal 63 of the sensor 62 is transmitted via the detection amplifier to a shutter opening/closing operation confirmation signal 72 (hereinafter referred to as confirmation signal). ). The operation of the optical shutters 12a and 12b (hereinafter referred to as optical shutters 12) will be explained with reference to the time chart shown in FIG. When turning on the optical shutter 12, the time
When the shutter signal 71 is switched from H to L at _T1 ,
The voltage at the input terminal 43 rapidly rises from 0V to +5V, and at the same time the mirror 50 begins to rotate, and at time T ₂
When reaching , the reflective surface 52 of the mirror 50 completely cuts off the laser beam optical path, and the laser beam 3R begins to enter the sensor 62, so the confirmation signal 72 changes from H to L. Furthermore, the mirror 50 continues to rotate and the time
At T ₃ , the rotation angle reaches +15° and the rotation stops. In contrast to the above, when turning off the optical shutter 12, when the shutter signal 71 is switched from H to L at time _T4 , the voltage at the input terminal 43 rapidly decreases from +5V to 0V, and at the same time the mirror 50 The rotation angle decreases from +15° and approaches 0°.
Then, at time _T5 , the laser beam 3R leaves the sensor 62, so the confirmation signal 72 changes from L to H.
When the time T ₆ approaches, the reflecting surface 52 becomes almost parallel to the laser beam path. Therefore, the laser beam 3
P begins to leak from the opening 64, and at time T ₆ ,
The mirror 50 reaches a rotation angle of 0° and stops rotating.
The laser beam 3 directly becomes a laser beam 3P and passes through the optical shutter 12. Next, trimming stations constituted by optical shutters 12a, 12b and optical scanners 5a, 5b are referred to as STa and STb, and the trimming method in this embodiment will be described in detail with reference to FIG. In STa, trimming is performed in the order of adjustment items A ₁ and A ₂ , and in STb, trimming is performed in the order of adjustment items B ₁ and B ₂ . In this case, STa and STb perform trimming alternately. For example, in STa, when trimming the resistor 6a with laser beam 3a, in STb, the optical shutter 12b cuts off the laser beam 3b and does not perform trimming, and conversely, when STb performs trimming, in STa, trimming is not performed. do not have. STa and STb
When the trimming start conditions are satisfied at the same time, STa starts trimming with priority over STb. Now, STa is the condition setting for adjustment item A ₁ (a), STb
Assume that condition setting (a) for adjustment item B ₁ is started at the same time. In the condition setting (a), the measurement/control unit 8 sends the power supply voltage, test signals, and various control signals to the electric circuits on the boards 7a and 7b, and the circuits are adjusted to the adjustment items.
Bring the operating state to meet the adjustment specifications of A ₁ and B ₁ . Next, STa and STb go through their respective condition settings (a) and enter a stabilization time (b), but this stabilization time (b) is defined as the minimum necessary stabilization time for each adjustment item as an adjustment specification. Here, it is assumed that the disturbance in the electric circuit, which has entered a transient state due to the application of various signals according to condition setting (a), has subsided and the test signals 9a and 9b are waited until it becomes possible to measure them. After completing the condition setting (a) and stabilization time (b),
STa and STb acquire the trimming start conditions, but
In the example, STa ends the stabilization time (B) before STb, so only STa has the measurement time (C) and calculation time (D).
and operation time (e) and subsequent trimming, while STb continues to extend the stabilization time (b). STa opens the shutter (f) at the same time as the first measurement time (c), and at the measurement time (c), the measurement/control unit 8 measures the test signal 9a. Also, in the shutter opening (F),
The measurement/control unit 8 outputs a control signal 10a to operate the optical shutter 12a so that the laser beam 3a can pass through the optical shutter 12a. In the case of this embodiment, the operation time required to open and close the optical shutters 12a and 12b was approximately 10 ms. In the next calculation time (d), the measurement/control unit 8 performs arithmetic processing determined by the measurement results of the test signal 9a. In the next operating time (E), the laser beam 3a is transmitted to the resistor 6.
The starting point and ending point, scanning speed, and pulse oscillation frequency of the laser beam 3a are determined when scanning the area 3a. In addition, during the operation time (e), the measurement/control unit 8 sends control information such as the start point, end point, and scanning speed to the control signal 1.
0a to the optical scanner 5a, and the optical scanner 5a is operated to scan the laser beam 3a from the starting point to the ending point on the resistor 6a. At the same time, the pulse oscillation frequency of the laser beam 3a and control information for starting and stopping the pulse oscillation are transmitted to the Q switch 2 via the control signal 11 and operated, and the optical scanner 5a starts scanning the laser beam 3a from the starting point. When scanning is completed, the Q switch 2 is turned on and the oscillation of the laser beam 3 is started (h), and when the scanning is completed at the end point, the Q switch 2 is synchronously turned off and the oscillation of the laser beam 3 is stopped. . As a result, part of the low antibody 6a is removed,
Since the resistance value increases, the value of the test signal 9a changes, so repeat the order of measurement time (c), calculation time (d), and operation time (e) several times to gradually change the value of the test signal 9a. Close to the target value, and finally confirm that the measurement time (c) matches the target value, and finish trimming that adjustment item. Note that the end point of the γ-th calculation time (d) and the (γ+
1) Since the starting points of the first calculation time are determined to coincide with each other, the machined grooves formed on the resistor 6a during the plurality of operation times (e) become continuous grooves. In adjustment item _A1 , the order of measurement time (c), calculation time (d), and operation time (e) is repeated four times, and finally, measurement time (c) is performed once again to finish. At the next moment, STa sets the conditions for adjustment item _A2 (a) and closes the optical shutter (g), and STb opens the optical shutter (f) and calculates the calculation time (c). At this point, in STa, the condition setting (a) and stability time (b) of adjustment item A ₂ have not been processed, and in STb, the condition setting (a) and stability time (b) of adjustment item B ₁ have been processed. be. Therefore, trimming starts from STb when the trimming start conditions are met.
Migrate to STb. The measurement/control unit 8 receives a control signal 10
a to close the optical shutter 12a and release the laser beam 3.
a, and conversely open the optical shutter 12b using the control signal 10b to allow the passage of the laser beam 3b. Thereafter, STb performs trimming of adjustment item _B1 in the same procedure as STa. This embodiment described above has the following advantages. (a) Trimming is performed alternately in STa and STb, so
A single measuring section with an input switching function can handle the problem, and unlike the conventional method, two independent measuring sections are not required, making the measuring section inexpensive. (b) By making the mirrors 50 of the optical shutters 12a and 12b made of aluminum and reducing the ratio of weight to driving torque, the optical shutters can achieve high-speed response (10 ms). (c) By improving the reflectance of the reflective surface 52 provided on the mirror 50 to the laser beam, the required intensity of the laser beam 3R input to the sensor 62 is ensured, and the reflective surface 52 is processed with a satin finish to emit the laser beam. By adjusting the intensity of 3R, an optical attenuator for adjusting the laser beam intensity in front of the sensor 62 is no longer necessary. (d) By blackening the inner surface of the cover 60, it is possible to prevent the light scattered by the reflective surface 52 from being secondarily reflected on the inner surface of the cover 6. Therefore, when the optical shutters 12a and 12b are closed,
The leakage of laser light from the openings 61, 64 of the cover 60 is reduced, and the optical shutters 12a,
Since the closing operation of 12b is confirmed by the sensor 62, safety can be improved. (e) A comparison of the processing capacity ratio and price of this embodiment and the conventional example is as shown in the table below.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to substantially configure two to three trimming stations with one laser oscillator, and at the same price as conventional trimming devices, the processing capacity is significantly increased. can be improved. In other words, a trimming device with good cost performance can be obtained.

[Brief explanation of drawings]

1 and 2 are diagrams showing the configuration of a conventional laser trimming device and a time chart during trimming, FIG. 3 is a configuration diagram showing an embodiment of the laser trimming device of the present invention, and FIG. A partially cutaway perspective view of the optical shutter of the same embodiment, FIG. 5 is an explanatory diagram of the operating principle of the scanner in FIG. 4, FIG. 6 is an explanatory diagram of the driver for driving the optical shutter, and FIG. 7 is an illustration of the operation of the optical shutter. Diagram showing an explanatory time chart,
FIGS. 8 and 9 are time charts illustrating different trimming methods in this embodiment, respectively. 1...Laser oscillator, 2...Q switch, 3,
3a, 3b... Laser light, 4a... Beam splitter, 5a, 5b... Optical scanner, 6a, 6b
...Workpiece, 7a, 7b...Substrate, 8...Measurement/control unit, 9a, 9b...Inspection signal, 10a,
10b... Control signal, 12a, 12b... Optical shutter, 30a... Scanner case, 30... Scanner body, 31... Rotating shaft, 33, 35... Yoke, 34, 36... Magnet, 43... Input terminal ,5
0...Mirror, 52...Laser beam reflecting surface, 60...
...Cover, 61, 64...Laser light inlet/outlet, 6
2...Sensor, 63...Output terminal for laser light detection.

Claims (1)

[Claims] 1. A beam splitter splits a laser beam from a laser oscillator with a built-in Q-switch, and a light beam is provided in each optical path of the divided laser beam to control the cutting and passing of the laser beam. A shutter, an optical scanner that focuses a laser beam onto a minute spot and scans the workpiece, and a board on which the workpiece is attached are sequentially arranged, and the electrical circuit including the workpiece is inspected. A measurement/control unit for inputting signals is provided, and each control signal output from the measurement/control unit controls the Q switch, each optical shutter, and each optical scanner, thereby trimming each of the workpieces. A laser trimming device characterized in that the laser trimming is performed alternately or simultaneously. 2 The above-mentioned optical shutter consists of a movable iron piece integrally connected to a rotating shaft, and a set of coils wound around the movable iron piece, which are arranged oppositely in a circular manner surrounding the movable iron piece with a narrow gap between them. A scanner body consisting of a yoke and a set of magnets, a scanner case that houses the scanner body and through which an input terminal connected to the coil passes, and a scanner case that is formed in a cylindrical shape and includes a rotation center line at the top thereof. a mirror that has a laser beam reflecting surface that is polished and has a matte finish and that is fixed to the rotating shaft; a sensor that is disposed opposite to the laser beam reflecting surface and that includes an output terminal for detecting laser beam; and these mirrors. 2. The laser trimming device according to claim 1, further comprising a cover having a built-in sensor, an inlet/outlet for laser light, and a cover having an inner surface treated with black.