JP5310452B2 - Laser processing apparatus and laser processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve precision of trimming of a resistor. <P>SOLUTION: A comparison unit 172, when determining that the resistance value of the resistor measured by a measurement unit 131 reaches a switching change resistance value, commands an excitation light source control unit 182 to change a working condition through an external equipment interface unit 181. The excitation light source control unit 182 controls an excitation light source to widen the pulse width of a laser pulses emitted from a fiber laser 113 and to lower peak power. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method, and more particularly to a laser processing apparatus and a laser processing method for trimming a resistor.

  Conventionally, in a laser processing apparatus that performs trimming of a resistor, a laser pulse having a constant frequency, pulse width, and peak power emitted from a solid-state laser is used. FIG. 1 is a diagram schematically illustrating a state in which trimming of a resistor 11 provided between two electrodes 12a and 12b is performed using a laser pulse having a constant frequency, pulse width, and peak power. is there. In this example, by performing trimming, a groove 11A having a width W is formed in a direction (lateral direction in the figure) perpendicular to a direction in which a current flows between the electrode 12a and the electrode 12b.

  Further, since the frequency of the laser pulse is constant, the irradiation positions n-4 to n of the illustrated laser pulse are equally spaced. That is, the byte size ΔL, which is the interval between the irradiation positions of adjacent laser pulses, is constant. Further, since the pulse width and the peak power of the laser pulse are constant, the processing energy of the laser pulse determined by the peak power × pulse width is also constant. Since the tool size ΔL and the processing energy are constant, the amount of change in resistance value due to each laser pulse is also substantially constant.

  However, when the amount of change in the resistance value due to each laser pulse is constant, as shown in FIG. FIG. 2 is a graph showing changes in the resistance value of the resistor 11 when the laser pulses n-4 to n are irradiated. The horizontal axis indicates time, and the vertical axis indicates the resistance value.

  As shown in this figure, the resistance value of the resistor 11 changes most greatly immediately after the laser pulse is irradiated, and then gradually changes until the next laser pulse is irradiated. Further, as described above, since the byte size ΔL and the processing energy of the laser pulse are constant, the change amount ΔRa1 of the resistance value due to each laser pulse is substantially constant. Therefore, as shown in FIG. 2, when the allowable range of the resistance value after trimming is the range from the resistance value Rg1 to the resistance value Rg2, the resistance value of the resistor 11 is changed to the resistance value Rg1 by the laser pulse n-1. When reaching a close value, the resistance value exceeds the resistance value Rg2 due to the laser pulse n, and the desired trimming accuracy may not be obtained.

  On the other hand, when the byte size ΔL and the processing energy of the laser pulse are set so that the change amount ΔRa1 is small, desired trimming accuracy can be easily obtained, but the time required for trimming becomes long.

  Therefore, conventionally, when the difference between the resistance value of the resistor 11 and the resistance value Rg1 is equal to or less than the change amount ΔRa, it has been proposed to shorten the laser pulse emission interval and shorten the byte size ΔL ( For example, see Patent Document 1).

  Specifically, as shown in FIG. 3, when the difference between the resistance value of the resistor 11 and the resistance value Rg1 is equal to or less than ΔRa1 after irradiation with the laser pulse n−1, FIG. 3 and FIG. As shown, the frequency of the laser pulse is increased and the time interval between laser pulse n-1 and laser pulse n is shortened. As a result, the area where the resistor 11 is processed (cut) by the laser pulse n is reduced, and the change amount ΔRa2 of the resistance value due to the laser pulse n is smaller than the change amount ΔRa1 so far. Therefore, trimming can be performed so that the resistance value of the resistor 11 falls within the allowable range.

JP 2001-326112 A

  By the way, even after trimming, the resistance value of the resistor 11 changes due to microcracks generated after trimming. For example, as shown in FIG. 5, after forming a groove 11A having a length X in the resistor 11 by trimming, a microcrack 11B having a length ΔX is generated in the right direction from the right end of the groove 11A. The length of the cut (groove 11A + microcrack 11B) formed is increased, and the resistance value of the resistor 11 is increased by ΔRb.

  On the other hand, the higher the processing energy density of the laser pulse applied to the resistor 11, the greater the amount of microcracks that are generated, and the greater the amount of change in resistance caused by the microcracks. In the invention described in Patent Document 1, the processing energy density of the laser pulse irradiated to the right end portion of the groove 11A to be formed increases as the interval between the last two laser pulses (byte size ΔL) becomes shorter. Therefore, the change amount ΔRb2 (FIG. 3) of the resistance value after trimming according to the invention described in Patent Document 1 is the change amount ΔRb1 of the resistance value after trimming using a laser pulse having a constant frequency (FIG. 3). (Fig. 2) Therefore, as shown in FIG. 3, the resistance value of the resistor 11 may be within the allowable range immediately after trimming, but may subsequently exceed the resistance value Rg2 due to microcracks. .

  The present invention has been made in view of such a situation, and is intended to improve the accuracy of trimming of a resistor.

A laser processing apparatus according to one aspect of the present invention is a laser processing apparatus for processing a part of a resistor by irradiating a laser pulse and adjusting a resistance value of the resistor. A measuring means for measuring the resistance value of the resistor and a control means for controlling the laser pulse emission conditions are provided, and the control means emits a laser pulse under a first condition having a predetermined frequency, pulse width and peak power. It is, when the resistance value of the measuring means to measure the resistor exceeds a predetermined threshold value, at the same frequency as the first condition, and broaden the pulse width than the first condition, lowering the peak power, working Control is performed so that the laser pulse is emitted under the second condition in which the processing energy is reduced to such an extent that the amounts are substantially equal .

In the laser processing apparatus according to one aspect of the present invention, when the laser pulse is emitted under the first condition of the predetermined frequency, the pulse width, and the peak power, and the resistance value of the resistor exceeds the predetermined threshold, Laser pulses are emitted under the second condition with the same frequency as the first condition, with the pulse width wider than the first condition, the peak power reduced , and the machining energy reduced to an extent that the machining amount is almost equal. The

  Therefore, the trimming accuracy of the resistor can be improved.

  This laser processing apparatus is constituted by, for example, a laser trimming apparatus. This laser emitting means is constituted by, for example, a fiber laser. This measuring means is constituted by, for example, a resistance measuring instrument. This control means is comprised by processors, such as a computer or CPU, for example.

  This control means can set the pulse width and peak power of the laser pulse based on the size of the resistor and the target value of the resistance value.

  This makes it possible to set an appropriate pulse width and peak power according to the ease of processing of the resistor and the responsiveness of resistance measurement during processing, shortening the time required for trimming, and the resistor The trimming accuracy can be further improved.

  The control means can set the speed of processing the resistor and the frequency of the laser pulse based on the size of the resistor and the target value of the resistance value.

  This makes it possible to set the appropriate processing speed and the frequency of the laser pulse according to the ease of processing of the resistor and the responsiveness of resistance measurement during processing, shortening the time required for trimming, The accuracy of trimming of the resistor can be further improved.

  This laser emitting means can be constituted by a fiber laser.

  This makes it possible to easily change the frequency, pulse width, peak power, etc. of the laser pulse.

In the laser processing method according to one aspect of the present invention, a laser processing device that processes a part of a resistor by irradiating a laser pulse and adjusts the resistance value of the resistor has a predetermined frequency, pulse width, and peak power. A laser pulse is emitted under a certain first condition, the resistance value of the resistor is measured, and when the measured resistance value is equal to or greater than a predetermined threshold, the first frequency is the same as the first condition, and the first The method includes a step of emitting a laser pulse under a second condition in which the pulse width is expanded more than the conditions, the peak power is lowered , and the machining energy is reduced to an extent that the machining amount is substantially equal .

In the laser processing method according to one aspect of the present invention, when the laser pulse is emitted under the first condition of the predetermined frequency, the pulse width, and the peak power, and the resistance value of the resistor becomes equal to or higher than the predetermined threshold, Laser pulses are emitted under the second condition with the same frequency as the first condition, with the pulse width wider than the first condition, the peak power reduced , and the machining energy reduced to an extent that the machining amount is almost equal. The

  Therefore, the trimming accuracy of the resistor can be improved.

  This laser processing apparatus is constituted by, for example, a laser trimming apparatus.

  According to one aspect of the present invention, the accuracy of trimming of the resistor can be improved.

It is a figure for demonstrating the example of the trimming method of the conventional resistor. It is a figure for demonstrating the example of the trimming method of the conventional resistor. It is a figure for demonstrating the other example of the trimming method of the conventional resistor. It is a figure for demonstrating the other example of the trimming method of the conventional resistor. It is a figure for demonstrating the change of the resistance value of the resistor by a microcrack. It is a block diagram which shows one Embodiment of the laser processing apparatus to which this invention is applied. It is a block diagram which shows an example of a functional structure of the laser control part of a trimmer control part, and the control part of a fiber laser. It is a flowchart for demonstrating the trimming process performed by the laser processing apparatus. It is a table | surface which shows an example of process condition data. It is a table | surface which shows an example of process condition data. It is the table | surface which put together the relationship between the combination of the chip size and resistance value of a resistor, and the combination of the pulse width and peak power of the laser pulse to be set. It is a figure for demonstrating the relationship between the pulse width and peak power of a laser pulse, and the change of the resistance value of a resistor. It is a figure for demonstrating the effect of this invention. It is a figure for demonstrating the effect of this invention. And FIG. 11 is a block diagram illustrating an example of a configuration of a computer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 6 is a block diagram showing an embodiment of a laser processing apparatus to which the present invention is applied. The laser processing apparatus 101 of FIG. 6 processes a part of the resistor 103 mounted on the substrate 102 so as to be sandwiched between two electrodes 104a and 104b, and adjusts the resistance value of the resistor 103, for example. It is an apparatus capable of trimming. Note that the resistor 103 is constituted by, for example, a chip resistor.

  The laser processing apparatus 101 includes a personal computer (hereinafter referred to as a PC) 111, a trimmer control unit 112, a fiber laser 113, an optical unit 114, and probes 115a and 115b.

  The PC 111 acquires information regarding the resistor 103 input via an input unit (not shown). Further, the PC 111 changes a final target value of the resistance value of the resistor 103 (hereinafter referred to as a target resistance value) and a processing condition of the resistor 103, which are input via an input unit (not shown). A resistance value (hereinafter referred to as a switching change resistance value) as a threshold value for defining the timing is acquired.

  The PC 111 is based on the chip size, the target resistance value, the switching change resistance value of the resistor 103, and the processing condition data held inside which will be described later with reference to FIGS. 103 processing conditions are set. This processing condition includes at least the speed at which the resistor 103 is processed, the frequency of the laser pulse emitted from the fiber laser 113, the pulse width, and the peak power. The pulse width and peak power of the laser pulse are set to at least two types of values, that is, a value until the resistance value of the resistor 103 reaches the switching change resistance value and a value after reaching the switching change resistance value. .

  The PC 111 notifies the trimmer control unit 112 of the input target resistance value and switching change resistance value, and the set processing speed and laser pulse frequency. Further, the PC 111 notifies the control unit 141 of the fiber laser 113 of the set pulse width and peak power of the laser pulse.

  The trimmer control unit 112 controls the emission timing of the laser pulse and the irradiation position on the resistor 103 by controlling the fiber laser 113 and the optical unit 114. The trimmer control unit 112 is configured to include a measurement unit 131, a laser control unit 132, and an optical scanning unit 133.

  The measurement unit 131 is connected to the electrodes 104a and 104b via the probes 115a and 115b, measures the resistance value of the resistor 103 between the electrodes 104a and 104b, and notifies the laser control unit 132 of the measured resistance value. .

  The laser control unit 132 controls the emission timing of the laser pulse emitted from the fiber laser 113 and the change timing of the pulse width and peak power of the laser pulse via the control unit 141 of the fiber laser 113. In addition, when the resistance value of the resistor 103 measured by the measurement unit 131 reaches the target resistance value, the laser control unit 132 instructs the optical scanning unit 133 to stop scanning of the laser pulse.

  The optical scanning unit 133 controls the scanning direction and scanning speed of the laser pulses by the galvano scanners 152a and 152b via the driver 151 of the optical unit 114.

  The fiber laser 113 is a fiber laser using, for example, an optical fiber 142 formed of a rare earth element-doped optical fiber as a laser medium. Unlike the conventional solid-state laser, the fiber laser 113 can easily and rapidly change the frequency of the emitted laser pulse, the pulse width, and the peak power (= processing energy). On the other hand, in the conventional solid-state laser, it is necessary to use an attenuator or the like in order to change the processing energy of the laser pulse, and it cannot be changed at high speed. In the conventional solid-state laser, the frequency of the laser pulse can be changed, but the pulse width and the peak power are uniquely determined by the frequency, and there is no degree of freedom. The fiber laser 113 is a laser device that eliminates the weak points of these conventional solid-state lasers.

  The fiber laser 113 is configured to include a control unit 141, an optical fiber 142, and a head unit 143.

  The control unit 141 controls an excitation light source (not shown) to control the frequency, pulse width, and peak power of the laser pulse emitted from the head unit 143 via the optical fiber 142. Then, the laser pulse emitted from the head unit 143 enters the optical unit 114.

  The optical unit 114 is a device for scanning a laser pulse emitted from the fiber laser 113 and includes a driver 151, galvano scanners 152 a and 152 b, and an fθ lens 153.

  The galvano scanners 152 a and 152 b rotate around a predetermined rotation axis under the control of the driver 151, and the incident position and the incident angle of the laser pulse on the fθ lens 153 change depending on the rotation angle. The imaging position of the laser pulse on the processed surface of the resistor 103 moves in the horizontal direction in accordance with changes in the incident angle and the incident position on the fθ lens 153. That is, the irradiation position of the laser pulse on the resistor 103 is scanned by the galvano scanners 152a and 152b.

  FIG. 7 is a block diagram illustrating an example of functional configurations of the laser control unit 132 of the trimmer control unit 112 and the control unit 141 of the fiber laser 113.

  The laser control unit 132 is configured to include a comparison setting unit 171, a comparison unit 172, and a trigger pulse generation unit 173.

  The comparison setting unit 171 sets the target resistance value and the switching change resistance value notified from the PC 111 in the comparison unit 172.

  The comparison unit 172 compares the resistance value of the resistor 103 measured by the measurement unit 131 with the target resistance value and the switching change resistance value. When the resistance value of the resistor 103 reaches the switching change resistance value, the change of the processing condition is commanded to the excitation light source control unit 182 via the external device interface (INF) unit 181 of the fiber laser 113. When the resistance value of the resistor 103 reaches the target resistance value, the trigger pulse generation unit 173 is instructed to stop the trigger pulse, and the optical scanning unit 133 is instructed to stop scanning of the laser pulse.

  The trigger pulse generation unit 173 generates a trigger pulse having a frequency set by the PC 111 and supplies the trigger pulse to the excitation light source control unit 182 via the external device INF unit 181 of the fiber laser 113.

  The control unit 141 of the fiber laser 113 is configured to include an external device INF unit 181 and an excitation light source control unit 182.

  The excitation light source control unit 182 acquires the setting values of the pulse width and peak power of the laser pulse from the PC 111 via the external device INF unit 181. The excitation light source control unit 182 causes the laser pulse having the pulse width and peak power set by the PC 111 to be emitted from the head unit 143 via the optical fiber 142 in synchronization with the trigger pulse from the trigger pulse generation unit 173. In addition, an excitation light source (not shown) is controlled. Further, when receiving an instruction to change the processing conditions from the comparison unit 172 of the trimmer control unit 112, the excitation light source control unit 182 controls an excitation light source (not shown) to change the pulse width and peak power of the laser pulse. .

  Next, trimming processing executed by the laser processing apparatus 101 will be described with reference to the flowchart of FIG.

  In step S1, the laser processing apparatus 101 sets processing conditions. Specifically, the user inputs a target resistance value and a switching change resistance value to the PC 111 via an input unit (not shown). The PC 111 sets the processing speed, the frequency of the laser pulse, the pulse width, and the peak power by using the processing condition data that is created in advance and stored inside.

  9 and 10 show an example of the processing condition data. FIG. 9 shows processing condition data used for setting the processing speed and the frequency of the laser pulse, and FIG. 10 shows processing condition data used for setting the pulse width and peak power of the laser pulse. In addition, the upper part of each data column of FIG. 10 shows the pulse width of the laser pulse, and the lower part shows the peak power.

  In this example, the chip size of the resistor 103 is classified into three levels: large (for example, about 1608 size), medium (for example, about 1005 size), and small (for example, about 0603 size), and the target resistance value is It is classified into three stages: high (for example, 100 kΩ or more), medium (for example, 10 Ω or more and less than 100 kΩ), and low (less than 10 Ω). For each, data is set individually.

  Here, looking at each item of the processing condition data, the processing speed is determined by the ease of processing of the resistor 103 (hereinafter referred to as processability) and the response when measuring the resistance value (hereinafter, In consideration of the balance with measurement responsiveness), the target resistance value is set to be faster when the target resistance value is at a medium level than when the target resistance value is at a low level and at a high level. However, when the chip size of the resistor 103 is a small level, all are set to the same speed regardless of the target resistance value.

  In general, for the resistor 103, when the chip size is the same, the higher the target resistance value, the better the workability, while the measurement responsiveness deteriorates, and the lower the target resistance value, the worse the workability. On the other hand, the measurement response is improved.

  Considering the balance between the workability of the resistor 103 and the measurement response, the frequency of the laser pulse is maximized when the target resistance value is at a medium level, and is minimized when the target resistance value is at a high level. Is set. However, when the chip size of the resistor 103 is small, all are set to the same frequency regardless of the target resistance value.

  The byte size can be obtained by processing speed ÷ laser pulse frequency.

  As for the pulse width of the laser pulse, five types of 70 ns, 110 ns, 150 ns, 170 ns, and 230 ns are set for combinations of chip sizes and target resistance values of all the resistors 103. Hereinafter, as shown in FIG. 10, the laser pulse waveform has a pulse width of 70 ns as a waveform A, a pulse width of 110 ns as a waveform B, and a pulse width of 150 ns as a waveform. A waveform having a pulse width of 170 ns is referred to as waveform D, and a waveform having a pulse width of 230 ns is referred to as waveform E.

  In addition, peak power is set for each combination of the chip size, the target resistance value, and the pulse width of the resistor 103.

  The power per unit time of the fiber laser 113 can be obtained from the peak power of the laser pulse × pulse width × frequency. However, in consideration of the workability of the resistor 103, the target resistance value is obtained when the chip size is the same. Is set to be the largest when the level is low, and the smallest when the target resistance value is the high level. However, when the chip size of the resistor 103 is small, all are set to the same power regardless of the target resistance value.

  In addition, the processing energy per laser pulse is obtained by peak power × pulse width. For the same chip size and target resistance value, the peak power increases as the pulse width decreases, and the peak increases as the pulse width increases. Processing energy is set so that the power is reduced.

  FIG. 11 is a table summarizing the relationship between the combination of the chip size of the resistor 103 and the target resistance value and the combination of the pulse width and peak power of the set laser pulse based on the processing condition data of FIG. . For example, the combination of the pulse width and peak power of the laser pulse that is set when the chip size of the resistor 103 is a large level and the target resistance value is a high level is described as “large size, high resistance value” in the figure. It becomes a combination corresponding to the marked field. That is, when the chip size of the resistor 103 is a large level and the target resistance value is a high level, the pulse width and peak power of the set laser pulse are as follows: pulse width 70 nm, peak power 4.0 kW, pulse width 110 nm and peak It is a combination of any of power 2.7 kW, pulse width 150 nm and peak power 2.0 kW, pulse width 170 nm and peak power 1.8 kW, pulse width 230 nm and peak power 1.3 kW.

  By the way, even if the processing energy of the laser pulse is the same, when the pulse width and the peak power are different, the change in the resistance value of the resistor 103 due to the laser pulse is different.

  The graph on the left side of FIG. 12 shows changes in the resistance value of the resistor 103 when trimming is performed at the same constant processing speed using laser pulses having the same frequency and processing energy but different pulse widths and peak powers. It is a figure which shows an example. Note that the horizontal axis of the graph on the left side of FIG. 12 indicates time, and the vertical axis indicates the resistance value. In addition, the region on the left side of the vertical dotted line in the left graph of FIG. 12 shows the change in resistance value of the resistor 103 during trimming, and the region on the right side of the dotted line shows the change in resistance value of the resistor 103 after trimming. Show. Since the machining speed is constant, the horizontal axis direction can be read as the distance of the groove formed in the resistor 103 by trimming (= machining speed × time) in the area being trimmed in the left graph of FIG. It is.

  Also, a line 201 in the left graph of FIG. 12 shows a change in resistance value when a laser pulse having the uppermost waveform on the right side in FIG. 12 is used, and a line 202 is in the middle on the right side in FIG. A change in resistance value when a laser pulse having a waveform is used is shown, and a line 203 shows a change in resistance value when the laser pulse having the lowest waveform on the right side of FIG. 12 is used. In each graph on the right side of FIG. 12, the horizontal axis indicates time, and the vertical axis indicates power. Further, the value Pc indicates the minimum value (processing threshold value) of power necessary for processing the resistor 103.

  Therefore, a line 201 shows a change in resistance value when a laser pulse with a small pulse width and a large peak power is used, and a line 202 shows a resistance when a laser pulse having an intermediate pulse width and peak power is used. A change in value is shown, and a line 203 shows a change in resistance value when a laser pulse having a large pulse width and a small peak power is used.

  As shown in the graph on the left side of FIG. 12, when the processing energy of the laser pulse is the same, as the peak power increases and the pulse width decreases, the processing amount per laser pulse decreases, and the resistance value during trimming is reduced. While the change becomes smaller, the density of the processing energy becomes higher and microcracks are more likely to occur in the resistor 103, so that the change in resistance value after trimming becomes larger. Microcracks are caused by stress concentrated when the melted resistor 103 is solidified and by partial cutting of the resistor 103, resulting in the equilibrium being lost and stress concentrated on the tip of the cut portion. When the pulse width is small and the peak power is large, the melting and solidification time is short, and microcracks due to stress are likely to occur.

  On the other hand, the smaller the peak power and the larger the pulse width, the larger the processing amount per laser pulse and the greater the change in resistance during trimming, while the lower the processing energy density, and the resistance 103 micro Since the occurrence of cracks is suppressed, the change in the resistance value after trimming becomes small.

  Returning to FIG. 8, in step S <b> 1, the PC 111 determines the processing speed and the frequency of the laser pulse based on the processing condition data of FIG. 9, the chip size of the resistor 103 and the target resistance value.

  Further, the PC 111 uses a waveform of a laser pulse (hereinafter, referred to as “resonance pulse”) until the resistance value of the resistor 103 reaches the switching change resistance value based on the chip size of the resistor 103, the target resistance value, and the switching change resistance value. And a waveform of a laser pulse used after the resistance value of the resistor 103 reaches the switching change resistance value (hereinafter also referred to as a waveform after change). Thereby, the pulse width and peak power of the laser pulse before the resistance value of the resistor 103 reaches the switching change resistance value, and the pulse width and peak power of the laser pulse after reaching the resistance value are determined.

  The selection of the changed waveform can be roughly determined by the target resistance value. Specifically, the resistor 103 with a small target resistance value requires high peak power because the processability of the resistor 103 itself is not good. Therefore, a method of shortening the pulse width is effective for the waveform after change after reaching the switching change resistance value without changing the peak power much from the waveform before change. On the other hand, when the target resistance value is high, the processability of the resistor 103 is good. Therefore, it is effective to reduce the peak power and increase the pulse width from the pre-change waveform. In both cases, the processing energy is small.

  Here, the PC 111 has a wider pulse width after changing the waveform than before changing the waveform, and the amount of change in the resistance value of the resistor 103 during trimming per laser pulse (that is, one The pre-change waveform and post-change waveform are selected so that the change amount of the resistance value due to only the groove formed by the laser pulse is small. Therefore, at least after changing the waveform, the pulse width becomes wider, the peak power becomes smaller, and the machining energy becomes smaller after the waveform is changed.

  The PC 111 notifies the comparison setting unit 171 of the trimmer control unit 112 of the target resistance value and the switching change resistance value input by the user. The comparison setting unit 171 sets the notified target resistance value and switching change resistance value in the comparison unit 172. Further, the PC 111 notifies the determined pulse frequency of the laser pulse to the trigger pulse generation unit 173 of the trimmer control unit 112. Furthermore, the PC 111 notifies the determined processing speed to the optical scanning unit 133 of the trimmer control unit 112. The PC 111 notifies the determined pre-change waveform and post-change waveform to the excitation light source control unit 182 via the external device INF unit 181.

  In step S2, the laser processing apparatus 101 starts processing. Specifically, the trigger pulse generation unit 173 starts a process of generating a trigger pulse having a frequency set by the PC 111 and supplying the trigger pulse to the excitation light source control unit 182 via the external device INF unit 181.

  The excitation light source control unit 182 is synchronized with the trigger pulse from the trigger pulse generation unit 173 so that the laser pulse having the waveform before change set by the PC 111 is emitted from the head unit 143 via the optical fiber 142. A process for controlling an excitation light source (not shown) is started.

  The optical scanning unit 133 has a driver 151 for the optical unit 114 so that the speed at which the galvano scanners 152a and 152b scan the laser pulse in the predetermined processing direction on the processing surface of the resistor 103 becomes the processing speed set by the PC 111. The process of controlling is started.

  The measurement unit 131 starts the process of measuring the resistance value of the resistor 103 via the probes 115a and 115b and notifying the comparison unit 172 of the resistance value.

  Thereby, the process of measuring the resistance value of the resistor 103 is started while trimming the resistor 103 at the set processing speed using the laser pulse having the set frequency and the waveform before change.

  In step S3, the comparison unit 172 determines whether or not the switching change resistance value has been reached. Specifically, the comparison unit 172 compares the resistance value of the resistor 103 measured by the measurement unit 131 with the switching change resistance value. Then, when the resistance value of the resistor 103 is less than the switching change resistance value, the comparison unit 172 determines that the switching change resistance value has not yet been reached, and continues until the determination is made that the switching change resistance value has been reached. The determination process of step S3 is repeated at intervals.

  On the other hand, if the resistance value of the resistor 103 is greater than or equal to the switching change resistance value in step S3, the comparison unit 172 determines that the switching change resistance value has been reached, and the process proceeds to step S4.

  In step S4, the laser processing apparatus 101 changes the processing conditions. Specifically, the comparison unit 172 instructs the excitation light source control unit 182 to change the processing conditions via the external device INF unit 181. The excitation light source control unit 182 controls an excitation light source (not shown) so that the waveform of the laser pulse emitted from the head unit 143 via the optical fiber 142 becomes the changed waveform set by the PC 111. Thereby, the process of trimming the resistor 103 using the laser pulse having the changed waveform is started while keeping the processing speed and the frequency of the laser pulse constant.

  In step S5, the comparison unit 172 determines whether or not the target resistance value has been reached. Specifically, the comparison unit 172 compares the resistance value of the resistor 103 measured by the measurement unit 131 with the target resistance value. Then, when the resistance value of the resistor 103 is less than the target resistance value, the comparison unit 172 determines that the target resistance value has not yet been reached, and at a predetermined interval until it determines that the target resistance value has been reached. The determination process in step S5 is repeated.

  On the other hand, in step S5, when the resistance value of the resistor 103 is equal to or greater than the target resistance value, the comparison unit 172 determines that the target resistance value has been reached, and the process proceeds to step S6.

  In step S6, the laser processing apparatus 101 ends the processing. Specifically, the comparison unit 172 instructs the trigger pulse generation unit 173 to stop the trigger pulse, and the trigger pulse generation unit 173 stops the supply of the trigger pulse to the fiber laser 113. Thereby, the emission of the laser pulse from the fiber laser 113 is stopped. Further, the comparison unit 172 instructs the optical scanning unit 133 to stop scanning of the laser pulse. The optical scanning unit 133 controls the driver 151 to stop the operation of the galvano scanners 152a and 152b.

  Thereafter, the trimming process ends.

  Here, the effects of the present invention will be described with reference to FIGS. Hereinafter, the target resistance value is set to the resistance value Rg11, the allowable range of the resistance value after trimming is set to the range from the resistance value Rg11 to the resistance value Rg12, and the switching change resistance value is set to the resistance value Rc. It shall be.

  As shown in FIG. 13, when the resistance value of the resistor 103 exceeds the switching change resistance value Rc after irradiation with the laser pulse n-1, the pulse width is wider than the laser pulse n-1, A laser pulse n having a small peak power and a small processing energy is irradiated at the same time interval as before. Further, as described above, the waveform of the laser pulse n is set so that the change amount ΔRa12 of the resistance value of the resistor 103 during trimming by the laser pulse n is smaller than the change amount ΔRa11 by the previous laser pulse. Yes. Therefore, the resistance value of the resistor 103 can be made closer to the target resistance value Rg11.

  Further, as shown in FIG. 14, the byte size between the laser pulse n-1 and the laser pulse n is not different from the previous byte size, but the pulse width is widened. The processing amount is substantially equal to the processing amount up to the laser pulse n−1, although the processing energy is reduced. Further, as the peak power becomes smaller, the density of the processing energy of the laser pulse n becomes lower than the density of the processing energy up to the laser pulse n-1. Therefore, the amount of microcracks generated in the right direction from the right end of the groove 103A formed in the resistor 103 (that is, the direction in which the groove 103A extends) is reduced, and the change amount ΔRb11 of the resistance value of the resistor 103 after trimming is reduced. Can be small.

  Therefore, the resistance value of the resistor 103 can be more reliably within the allowable range, and can be adjusted to a value closer to the target resistance value Rg11.

  Further, in the laser processing apparatus 101, as described above, it is not necessary to change the frequency of the laser pulse, so that it is not necessary to adjust the processing speed accompanying the change of the frequency of the laser pulse. Therefore, the so-called processing pool is generated in which the laser pulse is repeatedly irradiated at substantially the same position without changing the processing speed in time, or adjacent laser pulses do not overlap, so that an unprocessed region is formed between them. Generation of machining separation is prevented.

  Thus, according to the laser processing apparatus 101, the trimming accuracy of the resistor 103 can be improved.

  13 and 14 show an example in which the laser pulse after changing the processing condition is irradiated only once. However, the switching change resistance value may be set so that the laser pulse is irradiated twice or more. Good.

  In the above description, an example in which the machining condition is changed only once has been described. However, two or more switching change resistance values may be set and the machining condition may be changed twice or more. Even when the machining conditions are changed twice or more, each time the machining conditions are changed, the pulse width of the laser pulse is widened, and the amount of change in the resistance value of the resistor during trimming per laser pulse is increased. What is necessary is just to set the waveform of a laser pulse so that it may become small.

  Furthermore, the configuration of the PC 111, the trimmer control unit 112, and the control unit 141 of the fiber laser 113 and the sharing of processing are not limited to the above-described example. For example, a part or all of the processing of the PC 111 may be executed by the trimmer control unit 112, or the PC 111, the trimmer control unit 112, and the control unit 141 of the fiber laser 113 may be combined into one device. Is possible.

  Furthermore, a series of processes of the PC 111, the trimmer control unit 112, and the control unit 141 of the fiber laser 113 described above can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software is installed in the computer. Here, the computer includes, for example, a general-purpose personal computer capable of executing various functions by installing various programs by installing a computer incorporated in dedicated hardware.

  FIG. 15 is a block diagram illustrating a configuration example of hardware of a computer that executes the above-described series of processing by a program.

  In a computer, a CPU (Central Processing Unit) 301, a ROM (Read Only Memory) 302, and a RAM (Random Access Memory) 303 are connected to each other by a bus 304.

  An input / output interface 305 is further connected to the bus 304. An input unit 306, an output unit 307, a storage unit 308, a communication unit 309, and a drive 310 are connected to the input / output interface 305.

  The input unit 306 includes a keyboard, a mouse, a microphone, and the like. The output unit 307 includes a display, a speaker, and the like. The storage unit 308 includes a hard disk, a nonvolatile memory, and the like. The communication unit 309 includes a network interface and the like. The drive 310 drives a removable medium 311 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

  In the computer configured as described above, the CPU 301 loads the program stored in the storage unit 308 to the RAM 303 via the input / output interface 305 and the bus 304 and executes the program, for example. Is performed.

  The program executed by the computer (CPU 301) can be provided by being recorded on a removable medium 311 as a package medium or the like, for example. The program can be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

  In the computer, the program can be installed in the storage unit 308 via the input / output interface 305 by attaching the removable medium 311 to the drive 310. Further, the program can be received by the communication unit 309 via a wired or wireless transmission medium and installed in the storage unit 308. In addition, the program can be installed in advance in the ROM 302 or the storage unit 308.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 101 Laser processing apparatus 103 Resistor 111 Personal computer 112 Trimmer control part 113 Fiber laser 114 Optical part 115a, 115b Probe 131 Measurement part 132 Laser control part 133 Optical scanning part 141 Control part 142 Optical fiber 143 Head part 151 Driver 152a, 152b Galvano Scanner 153 fθ lens 171 Comparison measurement unit 172 Comparison unit 173 Trigger pulse generation unit 182 Excitation light source control unit

Claims (5)

In a laser processing apparatus for processing a part of a resistor by irradiating a laser pulse and adjusting a resistance value of the resistor,
Laser emitting means for emitting the laser pulse;
Measuring means for measuring the resistance value of the resistor;
Control means for controlling the emission condition of the laser pulse,
The control means includes
The laser pulse is emitted under a first condition having a predetermined frequency, pulse width, and peak power,
When the resistance value of the resistor measured by the measuring means is equal to or higher than a predetermined threshold, the pulse width is broadened and the peak power is lowered at the same frequency as the first condition and more than the first condition. The laser processing apparatus is characterized in that the laser pulse is controlled to be emitted under a second condition in which the processing energy is reduced to an extent that the processing amount is substantially equal . The laser processing apparatus according to claim 1, wherein the control unit sets a pulse width and a peak power of the laser pulse based on a size of the resistor and a target value of the resistance value. 2. The laser processing according to claim 1, wherein the control unit sets the speed of processing the resistor and the frequency of the laser pulse based on a size of the resistor and a target value of the resistance value. 3. apparatus. The laser processing apparatus according to claim 1, wherein the laser emitting unit is a fiber laser. A laser processing apparatus that processes a part of the resistor by irradiating a laser pulse and adjusts the resistance value of the resistor,
Emitting the laser pulse under a first condition of a predetermined frequency, pulse width and peak power;
Measure the resistance value of the resistor,
When the measured resistance value is equal to or greater than a predetermined threshold value, the same frequency as the first condition, the pulse width is widened than the first condition, the peak power is lowered , and the processing amount is almost equal. A laser processing method comprising: emitting the laser pulse under a second condition in which processing energy is reduced to such an extent that

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