JP2004063797A - Laser trimming device and laser trimming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a trimming device and trimming method capable of suppressing increase in the number of trimming processes. <P>SOLUTION: When resistance values are measured at a resistance value measuring stage after a trimming amount is decided based on relation data between the previously stored trimming amount and a resistance value change amount and its measured value, a trimming is performed at a trimming stage in which a probe 46 is not located on a substrate 12. Therefore, as the probe does not disturb a trimming operation at any place where the probe 46 is placed, the placement is not restricted in association with the trimming. Accordingly, even if a plurality of thickness film resistors as a target of the trimming are provided on the substrate 12 with a high density as the probe can also be provided at a position covering the thickness film resistors, the number of probes which can be used for one time measurement of the resistance value is increased. Therefore, the number of times of dividing the trimming is reduced to shorten a processing time, and also costs of processing are decreased. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a laser trimming device and a laser trimming method.
[0002]
[Prior art]
When manufacturing a thick-film circuit board having a thick-film resistor, laser trimming is performed to finely adjust the resistance value of the thick-film resistor. In this laser trimming, while the resistance value is measured by abutting a probe electrode (probe) against the terminal of a thick film resistor, a cut is made in a part of the resistance with a laser beam to increase the resistance value to a desired value. Increase.
[0003]
[Problems to be solved by the invention]
In general, a thick film circuit board is provided with a plurality of thick film resistors. In the laser trimming, a plurality of thick film resistors for measuring the resistance value of each of the plurality of thick film resistors are used. A probe card 70 as shown in FIGS. 6 and 7 having the above-described probe electrode (probe) on a single substrate is used. FIG. 7 shows a cross section at an appropriate position in FIG.
[0004]
In both figures, the probe card 70 has, for example, a size sufficiently larger than the area in which the thick film resistor 40 is provided in the center of the printed wiring board 72, and in the figures, the thick film in which it is provided. A plurality of probe electrodes 76 are fixed to the peripheral portion of the opening 74 provided with an area larger than the circuit board 12 such that the tips of the probe electrodes 76 are directed toward the inner peripheral side and downward, that is, toward the thick film resistor 40 side. Things. When performing laser trimming, the probe card 70 is arranged above the thick film circuit board 12 and the probe electrode 76 is abutted against the terminal or the like of the thick film resistor 40 at the tip having a small diameter, and the opening is formed. 7 is irradiated with laser light from above in FIG.
[0005]
However, in such a probe card 70, since the probe electrode 76 extends from the peripheral edge of the opening 74 toward the inner peripheral portion, the position where the probe electrode 76 can be arranged while avoiding the laser beam to be irradiated is limited. Is done. In addition, since the base end of the probe electrode 76 is fixed to the printed wiring board 72 by soldering or the like, the arrangement pitch of the base end, which is increased based on the necessity such as mechanical strength, becomes relatively large. Therefore, when a large number of thick film resistors 40 are provided on the thick film circuit board 12, it is difficult to provide a single probe electrode 76 corresponding to all of them. Therefore, since a plurality of cards 70 are required for one type of thick film circuit board 12, the trimming process is divided into a plurality of times, and the number of divisions increases as the arrangement density of the thick film resistors 40 increases. Because of the increase, the prolonged processing time and the increase in processing cost due to the recent tendency to increase the density of thick film circuits have become problems.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a trimming device and a trimming method capable of suppressing an increase in the number of trimming steps.
[0007]
[First means for solving the problem]
In order to achieve the above object, the gist of the first invention is to provide laser trimming for adjusting the resistance value of each of a plurality of thick film resistors formed on a thick film circuit board to a target value. An apparatus for storing (a) relational data for preliminarily storing relational data between a trimming amount and a resistance change amount of the thick-film resistor; and (b) the thickness control means disposed at a predetermined first position. A resistance value measuring device for measuring a resistance value by bringing a plurality of probe electrodes into contact with each of the terminals of the plurality of thick film resistors on the membrane circuit board from above, (c) Trimming amount determination for determining each trimming amount for matching each resistance value to the target value based on the measured resistance values of the plurality of thick film resistors and the stored relation data. Means, (d) the first position and the plurality A moving device for relatively moving the thick film circuit board with respect to the resistance value measuring device between a second position at which the probe electrode of the thick film circuit board is not positioned on the thick film circuit board; Trimming means for trimming each of the plurality of thick film resistors on the thick film circuit board arranged at two positions by the determined amount of trimming.
[Second means for solving the problem]
The gist of the second invention for achieving the above object is that a laser for adjusting the resistance of each of a plurality of thick film resistors formed on a thick film circuit board to a target value. A trimming method, wherein (a) contacting a plurality of probe electrodes from above each of the terminals of the plurality of thick film resistors on the thick film circuit board arranged at a predetermined first position. A resistance value measuring step of measuring each resistance value, and (b) a relation between a trimming amount of the thick film resistor and a resistance value change amount stored in advance, and the measured resistance value. A trimming amount determining step of determining a trimming amount for matching each resistance value of the plurality of thick film resistors to the target value; and (c) searching the plurality of thick film resistors from the first position. Second position where the needle electrode is not located on the thick film circuit board And (d) moving the thick film circuit board relative to the resistance value measuring device until: (d) moving the plurality of thick film resistors on the thick film circuit board arranged at the second position. Trimming each of them by the determined amount of trimming.
[0008]
【The invention's effect】
With this configuration, when the resistance value measurement using the probe electrode is performed at the first position, the trimming amount is determined based on the relation data between the trimming amount and the resistance value change amount stored in advance and the measured value. Is determined, and trimming is performed by the trimming amount at a second position where the probe electrode is not positioned on the thick film circuit board. Therefore, no matter how the probe electrodes are arranged, the probe electrodes do not hinder the trimming, so that the arrangement is not limited in relation to the trimming. Therefore, even if a large number of thick film resistors to be trimmed are provided at high density on the thick film circuit board, the probe electrode can be provided at a position covering the thick film resistor, so that one time The number of probe electrodes that can be used for resistance value measurement increases. As described above, the number of times of trimming is reduced, so that the processing time is shortened and the processing cost is reduced.
[0009]
Note that the relationship data between the trimming amount and the resistance value change amount can take various forms in relation to the trimming control method. For example, the trimming amount can be a length dimension Δa cut by a laser or a ratio (Δx / x) of the cut dimension Δx to the initial dimension x in the cut direction. Further, the amount of change in the resistance value may be an increment ΔR of the resistance value or a ratio (ΔR / R) of the increment ΔR to the initial resistance value R.
[0010]
Other aspects of the invention
Here, preferably, the laser trimming device includes a design value storage unit for previously storing design values (for example, a width dimension, a length dimension, and a target resistance value) of the thick film resistor, The relation storage means stores the trimming amount represented by a ratio Δx / x between an initial dimension and a cut dimension in a cutting direction and a resistance change amount represented by a ratio ΔR / R between an initial resistance value and an increment. The relationship is stored as the relationship data, and the trimming amount determining means includes a ratio Δx corresponding to a ratio ΔR / R between the difference ΔR between the target resistance value and the measured resistance value R and the resistance value R. / X is used to determine the trimming amount Δx. Preferably, the laser trimming method includes a design value storage step for storing the design value in advance, and the trimming amount determining step includes the ratio ΔR / R and the ratio Δx / x stored in advance. And the difference ΔR between the target resistance value and R to determine the trimming amount Δx. In this way, the relational data does not depend on the thickness t or the specific resistance (resistivity) ρ of the thick-film resistor, but is expressed by the ratio L / W of the length L and the width W in the current direction. Therefore, the ratio can be commonly used for a plurality of thick film resistors having the same ratio.
[0011]
Preferably, the plurality of probe electrodes are provided on a probe card disposed above the thick film circuit board so as to cover the thick film circuit board, and an opening provided at a central portion of the probe card. The terminal is brought into contact with the terminal at the tip protruding downward from the portion. In laser trimming using such a general probe card, the base of the probe electrode is fixed outside the inner peripheral edge of the opening. When a large number of thick film resistors are arranged at a high density on the side, the positional relationship is likely to be such that the intermediate portion of the probe electrode covers the thick film resistor. Therefore, conventionally, it was necessary to perform trimming by dividing into a large number of times. By applying the present invention, the effect of reducing the number of times of trimming can be remarkably obtained.
[0012]
Preferably, the relation data is obtained by trimming each of the plurality of thick film resistors while measuring their resistance values. That is, the relationship data between the resistance change amount and the trimming amount can be theoretically obtained from the resistivity specific to the material and the dimensions of the thick-film resistor, but if the relationship data obtained by actually measuring is used. In addition, since errors due to variations in dimensions and shapes at the time of forming a thick film are eliminated, the accuracy of the resistance value after trimming is further improved.
[0013]
Preferably, the trimming method trims a part of the thick-film resistor on the thick-film circuit board while measuring its resistance value, and trims the remainder based on the measured value and the relationship data. It is to trim. With this configuration, the resistance of the thick film resistor that can be trimmed without being disturbed by the probe electrode can be monitored during the trimming, so that there is an advantage that the accuracy of the resistance value after the trimming can be improved. That is, when trimming a thick-film resistor on a single thick-film circuit board, a method of measuring the resistance value and then trimming using related data, and a conventional method of trimming while measuring the resistance value are used. Can also be used in combination.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a schematic diagram for explaining a configuration of a laser trimming device (hereinafter, referred to as a trimming device) 10 according to one embodiment of the present invention. In the figure, a trimming device 10 includes a thick film circuit board (hereinafter, referred to as a substrate) 12 to be trimmed, and a transfer device 14 such as a belt conveyor for transferring the thick film circuit board 12 in one direction. It comprises a first resistance value measuring device 16, a laser irradiator 18, a second resistance value measuring device 20, and a control device 22 for controlling these. In the present embodiment, the above-described transport device 14 corresponds to a moving device.
[0016]
The first resistance value measuring device 16 includes a positioning mechanism for fixing the substrate 12 transferred by the transfer device 14 at a predetermined fixed position, and a plurality of the plurality of resistance members formed on the substrate 12. It has a probe card 24 and the like disposed above the thick film resistor 40 (see FIGS. 3 and 5) to measure the resistance value of each. The second resistance value measuring device 20 is configured similarly to the first resistance value measuring device 16 described above.
[0017]
The laser irradiator 18 is a YAG laser device that generates an infrared laser having a wavelength of, for example, about 1 (μm). The light 26 is irradiated. The output of the laser irradiator 18 is, for example, about 1 to 10 (W), and the pulse repetition rate (Q rate) is, for example, about 1 to 10 (kHz).
[0018]
The control device 22 includes a CPU, a ROM, a RAM, and the like. According to a program stored in the ROM in advance, the first resistance value measuring device 16 and the laser irradiator 18 are used while using the temporary storage function of the RAM. , And the second resistance value measuring device 20. That is, by moving the probe card 24 of the first resistance value measuring device 16 and the second resistance value measuring device 20 to a predetermined measurement position, the resistance value measurement process of the substrate 12 is executed, and the obtained measured value is measured. , The amount of trimming of the thick film resistor 40 is determined and temporarily stored in the RAM. Further, the laser beam 26 emitted from the laser irradiator 18 is applied to a predetermined position of the thick film resistor 40 to be trimmed so that the cut formed has the determined trimming amount.
[0019]
FIG. 2 is a functional block diagram illustrating functions of the control device 22. The design value storage means 30 stores design values, such as a width dimension W, a length dimension L, and a target resistance value, of each of the plurality of thick film resistors 40 formed on the substrate 12 to be subjected to the trimming process. Rm and the like are stored. As these design values, for example, design values of the thick film resistor 40 for each product number of the substrate 12 are stored in advance, and an operator operates an input device provided in the control device 22 or the like, and Is read at a predetermined address in the RAM. The above operation can be automatically performed by reading the product number information recorded on the substrate 12 using an image reader or the like while the substrate 12 is being transported by the transport device 14, for example. Alternatively, design values for each thick film resistor 40 may be directly input.
[0020]
The relational data storage means 32 stores relational data (which will be described in detail later) between the trimming amount and the resistance value change amount of the thick film resistor 40 measured in advance or theoretically (calculated), for example, in a RAM. To memorize. This relationship data may be stored as individual data for each of the plurality of thick film resistors 40 on the substrate 12, but may be stored for each specification of the thick film resistor 40, ie, the same width dimension W and length dimension. The data may be stored as common data for each L. The relational data includes, for example, the ratio of the cut length dimension Δx to the original length dimension x in the trimming cut direction (Δx / x) and the ratio of the resistance value increment ΔR to the original resistance value R (ΔR / R). Can be used. Such a correspondence between the ratios is general-purpose data that does not depend on the constituent material of the thick film resistor 40 or the thickness t, that is, common data for each specification of the thick film resistor 40.
[0021]
Instead of this, the one in which the cut length Δx is associated with the resistance increment ΔR may be used, but this depends on the original length dimension x in the cut direction, the original resistance value R, and the like. It becomes individual data for each of the resistors 40. In addition, a value obtained by associating the resistance value R with the cut length Δx required to increase the resistance value to the target resistance value Rm may be used as individual data for each thick film resistor 40.
[0022]
Further, the resistance value measuring means 34 controls the first resistance value measuring device 16 so that the thick film on the substrate 12 is positioned on the resistance value measuring stage provided with the first resistance value measuring device 16. The resistance value R before trimming of each of the resistors 40 is measured. In this resistance value measurement stage, for example, the resistance values of all the thick film resistors 40 are measured, but no trimming is performed. In this embodiment, the resistance value measuring stage corresponds to the first position.
[0023]
The trimming amount determining means 36 determines a trimming amount of each of the thick film resistors 40 based on the measured resistance value R and the above-described relation data and stores the trimming amount in the RAM. For example, when the relation data is a correspondence between Δx / x and ΔR / R, a difference between the resistance value R and the target value Rm, that is, a required resistance change amount ΔR is calculated, and ΔR / R The trimming amount Δx is determined from R and the original length dimension x in the cutting direction. The figure shows a case where the target value Rm is used in the trimming amount determination stage as described above. The trimming means 38 controls the laser irradiator 18 to irradiate the laser light 26 to each of the plurality of thick film resistors 40 on the substrate 12 located below the laser irradiator 18, that is, the trimming stage. The trimming is performed by the trimming amount. In the present embodiment, this trimming stage corresponds to the second position.
[0024]
FIGS. 3A and 3B are diagrams illustrating an example of relation data stored in the RAM by the relation data storage unit 32. FIG. (A) shows relational data in the case of a trimming shape called “straight line cut” in which the thick film resistor 40 is cut straight in the width direction (direction perpendicular to the current direction), and (b) shows the relation data in the width direction. The relationship data in the case of a trimming shape called "L-cut" in which a small cut is made and then cut in the length direction, that is, the current direction, from the tip is shown. In (a), the horizontal axis represents the ratio ΔW / W between the width dimension W and the cut length dimension ΔW, and in (b), the horizontal axis represents the ratio ΔL between the length dimension L and the cut length dimension ΔL in the current direction. / L, respectively, and the vertical axis indicates the ratio ΔR / R between the resistance value increment ΔR and the original resistance value R.
[0025]
(A) shows two curves A and B having different rates of change. Curve A is an example of data when the width W is sufficiently large (L << W) with respect to the length L, and the curve B is sufficiently small with respect to the length L ( L >> W) is an example of data. As shown in this figure, the relationship between the amount of trimming of the thick film resistor 40 and the amount of change in the resistance value is determined geometrically based on the shape thereof. If the ratio with respect to W is the same, substantially the same curve can be obtained regardless of the constituent material of the thick film resistor 40. Therefore, depending on the resistance tolerance of the thick film resistor 40 required for the substrate 12, its size A common curve relationship can be used for each. In the case of a trimming shape called “Z-cut” in which the two positions separated from each other in the current direction are alternately cut from both sides in the width direction, relationship data having a shape similar to the above-described straight-line cut can be obtained.
[0026]
Also, (b) also shows two straight lines C and D having different rates of change (gradients). The inclination of these straight lines C and D is determined according to the ratio ΔW / W of the cut length dimension ΔW in the width direction to the width dimension W. Since the inclination increases as the depth of cut in the width direction increases and ΔW / W increases, the rate of increase of the resistance value increment ΔR with respect to the cut length dimension ΔL in the current direction increases. Of the two straight lines C and D shown in the figure, the straight line C shows a case where the cutting depth ΔW is relatively large.
[0027]
Further, as shown in the figure, the rate of increase in resistance value ΔR / R is maintained at a constant slope in the L cut even when the cut length is increased, but increases as the cut length increases in the straight cut. The slope of the rate ΔR / R increases. For this reason, the trimming shape of the thick film resistor 40 is appropriately determined in consideration of these change characteristics and in consideration of a balance between the resistance value tolerance and the processing speed, and the related data corresponding to the predetermined trimming shape. Is stored in the RAM by the relational data storage means 32.
[0028]
The above-mentioned relational data is obtained, for example, by preparing a dummy substrate having the same specifications as the substrate 12 to be processed, measuring the resistance value by the resistance value measuring unit 34, and measuring the thick film resistance by the trimming unit 38. It is obtained by trimming the body 40. The measurement of the resistance value may be performed at an appropriately determined cycle so that the required resistance value tolerance is obtained. Further, the acquisition and storage of the relationship data may be performed using a dummy substrate particularly manufactured for acquiring the relationship data, prior to trimming a large number of substrates 12, but in a mass production stage of the substrate 12, It can also be performed using a semi-finished product that has undergone the process. Further, the trimming is not for the purpose of obtaining a desired resistance value of the thick film resistor 40, but for the purpose of obtaining the relationship between the trimming amount and the resistance value change amount. There is no need to trim while measuring.
[0029]
The trimming amount determining means 36 determines the trimming amount using such relational data. That is, if the ratio between the calculated resistance value increment ΔR and the original resistance value R is ΔR / R = k, the corresponding ratio ΔW / W = m is set as shown in FIG. Obtained from relational data. Since the width dimension W is input to the control device 22 in advance, the trimming amount is determined by substituting the values of m and W into the equation ΔW = mW.
[0030]
FIG. 4 is a process diagram illustrating an example of a trimming method using the trimming device 10 configured as described above. The process shown in the figure is a mass production stage that is performed after the related data is stored as described above. In the drawing, in a carrying-in step 42, the substrate 12 on which the thick film resistor 40 has been formed through the firing step is carried by the transfer device 14 to a resistance value measuring stage provided with the first resistance value measuring device 16. Next, in a resistance value measuring step 44, after the substrate 12 is fixed at a predetermined position, the probe card 24 is disposed at a predetermined height position above the substrate 12 and, as shown in FIG. A plurality of probes (probe electrodes) 46 are brought into contact with the terminals 48 of all the thick-film resistors 40 on the substrate 12, for example, and the respective resistance values are measured.
[0031]
FIG. 5 is a diagram showing a state in which the resistance value is being measured as viewed from above the probe card 24. In the figure, a probe card 24 is fixed to a printed wiring board 52 having, for example, a substantially rectangular opening 50 in a central portion by soldering or the like in a direction toward the inner peripheral side at a peripheral portion of the opening 50. And the plurality of probes 46 described above. The printed wiring board 52 is, for example, an alumina thin plate having a substantially rectangular shape. The printed wiring board 52 is attached to the first resistance value measuring device 16 or the second resistance value measuring device 20 at a terminal portion 54 provided at a lower end portion in FIG. It is connected to the electrical system.
[0032]
The plurality of probes 46 have a thin contact portion 56 with a diameter of, for example, about 0.3 (mm) at the distal end, similarly to the probe 76 used in the conventional trimming method shown in FIG. The distal end of the contact portion 56 protruding downward from the opening 50 is elastically pressed against the terminal 48 to ensure conduction between them. In this embodiment, the probe 46 is in contact with all the terminals 48 of the large number of thick film resistors 40 provided on the substrate 12 at the contact portions 56 thereof. All the resistance values are measured by this one probe card 24.
[0033]
As a result of the arrangement of the probes 46 for all the thick-film resistors 40 as described above, as shown in FIG. The probe 46 is brought into contact with the terminal 48 so as to cover the terminal 48. However, in this embodiment, no trimming (irradiation of the laser beam 26) is performed in the resistance value measuring step 44, so that there is no problem even if the probe 46 is positioned on the thick film resistor 40.
[0034]
Returning to FIG. 4, in the trimming amount determination step 58, each of the plurality of thick film resistors 40 provided on the substrate 12 is determined based on the measured resistance value and the relation data stored in advance. The amount of trimming, for example, in the case of a straight cut, the cutting depth ΔW in the width direction is all determined. Next, in the moving step 60, the substrate 12 having the measured resistance value is sent by the transfer device 14 to the trimming stage provided with the laser irradiator 18. That is, it is relatively moved with respect to the first resistance value measuring device 16.
[0035]
Next, in a trimming step 62, after positioning the substrate 12 at a predetermined position on the trimming stage, each of the plurality of thick film resistors 40 on the substrate 12 is irradiated with the laser beam 26 to perform trimming. At this time, the resistance value of the thick film resistor 40 is not measured during the trimming, and the output and the irradiation position of the laser beam 26 are set so that each trimming amount becomes the value determined in the trimming amount determining step 58. It is controlled according to the stored data. At this stage, the thick film resistor 40 is specified in a one-to-one correspondence with the measured value obtained in the resistance value measuring stage by positioning the substrate 12 at a predetermined position.
[0036]
In addition, during the above-described trimming, there is no obstacle between the substrate 12 and the laser irradiator 18 that obstructs the path of the laser light 26 as shown in FIG. That is, the trimming is performed in a state where the substrate 72 and the probes 76 of the probe card 70 are not located above the substrate 12 as in the case of the conventional trimming method shown in FIG. For this reason, as shown in FIG. 5 described above, even if the probe 46 has a positional relationship of covering the thick film resistor 40 during the measurement of the resistance value, such a state of the arrangement of the probe 46 is not considered. It does not hinder any trimming. That is, since there is no obstacle above the substrate 12, the resistance values of all the thick film resistors 40 can be adjusted by one trimming step without dividing the steps.
[0037]
After the trimming is completed as described above, in the resistance value measuring step 64, after the substrate 12 is moved from the trimming stage to the position where the second resistance value measuring device 20 is provided, the resistance value measuring step Similarly to 44, the resistance value after trimming is measured. When the resistance value data after trimming is obtained and recorded in this step, a series of trimming processing is completed, and in the sending step 66, the substrate 12 is sent to the next step. Note that the resistance value measurement step 64 need not be performed if the resistance of the thick film resistor 40 remains within the tolerance within the process capability.
[0038]
Here, in the present embodiment, when the resistance value measurement using the probe 46 is performed in the resistance value measurement stage, based on the relation data between the trimming amount and the resistance value change amount stored in advance and the measured value. After the trimming amount is determined by the trimming, trimming is performed at a trimming stage where the probe 46 is not located on the substrate 12. Therefore, no matter how the probe 46 is arranged, the probe 46 does not hinder the trimming, so that the arrangement is not limited in relation to the trimming. Therefore, even when a large number of thick film resistors 40 to be trimmed are provided on the substrate 12 at a high density, the probe 46 is also provided at a position covering the thick film resistors 40 as shown in FIG. As a result, the number of probes 46 that can be used for one resistance value measurement increases. As described above, there is an advantage that the number of times of trimming is reduced, the processing time is shortened, and the processing cost is reduced.
[0039]
In the present embodiment, the design value of the thick film resistor 40 is stored in advance, the trimming amount represented by the ratio of the initial dimension in the cutting direction to the cutting dimension (for example, ΔW / W), and the initial resistance. The relationship between the resistance value change amount represented by the ratio ΔR / R of the value and the increment is used as “relation data”, and the trimming amount determination means 36 determines the difference ΔR between the target resistance value Rm and the measured resistance value R. Since the trimming amount ΔW is determined from the ratio ΔW / W according to the ratio ΔR / R of the resistance value R to the resistance value R, the data is not necessarily acquired for each thick film resistor 40 because the versatility of the relational data is high. Since there is no need to keep the relationship, there is an advantage that the related data can be easily obtained.
[0040]
As described above, the present invention has been described in detail with reference to the drawings. However, the present invention can be implemented in other embodiments.
[0041]
For example, in the embodiment, the substrate 12 and the first resistance value measuring device 16 are moved relative to each other by the substrate 12 being sent in one direction by the transfer device 14. The resistance value measuring device 16 and the laser irradiator 18 may be moved while the position is kept at a fixed position, and the measurement of the resistance value and the trimming may be sequentially performed.
[0042]
In the embodiment, the trimming amount, that is, the cutting depth ΔW is determined and stored in the trimming amount determining step 58 based on the relation data stored in advance and the measured resistance value. May be sequentially determined when processing each of the plurality of thick film resistors 40 in the trimming step. That is, the resistance value measured in the resistance value measurement step 44 may be stored in the RAM, and this may be converted into a trimming amount during processing.
[0043]
In the embodiment, all the thick-film resistors 40 on the substrate 12 are trimmed in a state where the resistance is measured in advance and the resistance is not measured at the same time. The thick-film resistor 40 that does not have the same effect may be trimmed while measuring the resistance value as in the conventional case.
[0044]
In the embodiment, the relationship data between the trimming amount and the resistance value change amount is obtained by measuring the resistance value change while actually trimming the thick film resistor 40 on the substrate 12. It is also possible to use relational data theoretically obtained based on the resistivity specific to the material, the dimensions of each part, and the like.
[0045]
Further, in the embodiment, the resistance is determined by using the probe card 24 provided with a plurality of probes 46 that are brought into contact with the terminals 48 at the contact portions 56 at the tip end exposed in the openings 50 of the printed wiring board 52. Although the value is measured, the probe 46 may be directly fixed to the resistance value measuring devices 16 and 20. Further, in the present invention, since the probe card 24 does not need to transmit the laser light 26, the rear surface side (the substrate 12 side) of the printed wiring board having no opening 50 is placed on the rear surface. A probe card having probes set up vertically can also be used. That is, a probe having an appropriate structure and type can be used as a probe for measuring the resistance value as long as the resistance value of the thick film resistor 40 can be measured at the same time as much as possible.
[0046]
Further, the transfer device 14 is not limited to the conveyor type shown in the embodiment, but may be an appropriate type such as a robot type that sandwiches and moves the substrates 12 one by one.
[0047]
Further, in the embodiment, all the thick film resistors 40 on the substrate 12 are all processed in one resistance value measuring step 44 and one trimming step 62. When measurement and trimming are difficult, the process may be divided into two or more times. Also in this case, there is an advantage that the number of man-hours can be reduced as compared with the related art based on the fact that the three-dimensional crossing state between the thick film resistor 40 and the probe 46, that is, the positional relationship covered by the probe 46 may be acceptable.
[0048]
Although not specifically exemplified, the present invention can be variously modified without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of a laser trimming device according to an embodiment of the present invention.
FIG. 2 is a functional block diagram illustrating functions of a control device shown in FIG.
FIGS. 3A and 3B are diagrams illustrating an example of relation data between a trimming amount and a resistance value change amount.
FIG. 4 is a process diagram illustrating an example of a trimming method using the laser trimming device of FIG.
FIG. 5 is a plan view for explaining a measurement state of a resistance value in the laser trimming device of FIG. 1;
FIG. 6 is a plan view for explaining a trimming method in a conventional laser trimming device.
FIG. 7 is a sectional view at an appropriate position in FIG. 6;
[Explanation of symbols]
10: Laser trimming device
12: Thick film circuit board
14: Transfer device (moving device)
16: 1st resistance value measuring device (resistance value measuring device)
18: Laser irradiator
22: Control device
24: Probe card
26: Laser light

Claims (2)

A laser trimming apparatus for adjusting a resistance value of each of a plurality of thick film resistors formed on a thick film circuit board to a target value,
Relationship storage means for storing in advance the relationship data between the amount of trimming of the thick film resistor and the amount of change in resistance,
A plurality of probe electrodes are brought into contact with each of the terminals of the plurality of thick-film resistors on the thick-film circuit board arranged at a predetermined first position from above to measure respective resistance values. A resistance value measuring device for
Trimming amount determination for determining each trimming amount for matching each resistance value to the target value based on the measured resistance values of the plurality of thick film resistors and the stored relation data. Means,
A movement for relatively moving the thick film circuit board with respect to the resistance value measuring device between the first position and the second position where the plurality of probe electrodes are not positioned on the thick film circuit board; Equipment and
Trimming means for trimming each of the plurality of thick film resistors on the thick film circuit board disposed at the second position by the determined amount of trimming. Trimming device. A laser trimming method for adjusting a resistance value of each of a plurality of thick film resistors formed on a thick film circuit board to a target value,
A plurality of probe electrodes are brought into contact with each of the terminals of the plurality of thick-film resistors on the thick-film circuit board arranged at a predetermined first position from above to measure respective resistance values. A resistance value measuring step,
The resistance value of each of the plurality of thick film resistors is set to the target value based on the relation data between the trimming amount and the resistance value change amount of the thick film resistor stored in advance and the measured resistance value. A trimming amount determining step of determining each trimming amount to match the value,
A moving step of relatively moving the thick film circuit board with respect to the resistance value measuring device from the first position to a second position where the plurality of probe electrodes are not positioned on the thick film circuit board;
Trimming each of the plurality of thick-film resistors on the thick-film circuit board disposed at the second position by the determined amount of trimming. .

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