Laser processing device and laser processing method

Abstract

Provided are a laser processing device and a laser processing method that, even when processing is performed with processing laser light including high-frequency laser light, are capable of accurately determining a processing failure on the basis of the laser light energy during the processing. Specifically, a laser processing device 100 acquires a correlation between energy TE of low-frequency laser light LT and a light intensity corresponding value TN, which is a value corresponding to the intensity of the low-frequency laser light LT, and determines, on the basis of the acquired correlation and a processing light intensity corresponding value WN, which is a value corresponding to the intensity of processing laser light LW including high-frequency laser light, a processing failure in processing performed with the processing laser light LW including high-frequency laser light.

Description

Laser processing device and laser processing method

[0001] 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 that determine processing defects based on the energy of laser light during processing.

[0002] 2. Description of the Related Art Conventionally, a laser processing apparatus and a laser processing method are known that determine processing defects based on the energy of a laser beam during processing (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a laser processing device that processes a workpiece by irradiating the workpiece with a laser beam (laser light) reflected by a mirror. In the above-mentioned Patent Document 1, the output (energy) of leakage light of the laser beam (laser light) that is transmitted without being reflected by the mirror is measured, and processing defects are determined based on whether the output (energy) of the measured leakage light of the laser beam (laser light) is within a predetermined threshold value.

[0004] Japanese Patent Application Laid-Open No. 2021-30283

[0005] However, since the energy of high-frequency laser light in particular cannot be measured accurately, the laser processing device described in Patent Document 1 may not be able to accurately determine processing defects when processing with processing laser light including high-frequency laser light. Therefore, there is a need for a laser processing device and a laser processing method that can accurately determine processing defects based on the energy of the laser light during processing, even when processing with processing laser light including high-frequency laser light.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a laser processing apparatus and a laser processing method that are capable of accurately determining processing defects based on the energy of the laser light during processing, even when processing is performed using processing laser light that includes high-frequency laser light.

[0007] In order to achieve the above object, a laser processing apparatus according to a first aspect of the present invention includes a laser light irradiating unit that irradiates a laser light to process an object, an energy measuring unit that acquires the energy of low-frequency laser light having a frequency lower than a predetermined frequency from the laser light irradiated from the laser light irradiating unit, a light intensity acquiring unit that acquires a first light intensity correspondence value that is a value corresponding to the intensity of the low-frequency laser light when the energy measuring unit acquires the energy of the low-frequency laser light, and acquires a second light intensity correspondence value that is a value corresponding to the intensity of processing laser light including high-frequency laser light having a frequency equal to or higher than the predetermined frequency from the laser light irradiated from the laser light irradiating unit, and a control unit that acquires a correlation between the energy of the low-frequency laser light and the first light intensity correspondence value, and determines processing defects when processing with processing laser light including high-frequency laser light based on the acquired correlation and the second light intensity correspondence value.

[0008] In the laser processing apparatus according to the first aspect, as described above, a correlation between the energy of the low-frequency laser beam and a first light intensity correspondence value, which is a value corresponding to the intensity of the low-frequency laser beam, is acquired, and a processing defect is determined when processing using a processing laser beam including a high-frequency laser beam based on the acquired correlation and a second light intensity correspondence value, which is a value corresponding to the intensity of the processing laser beam including a high-frequency laser beam. Here, unlike the energy of the laser beam, the value corresponding to the intensity of the laser beam can be accurately acquired even for high-frequency laser beams and is correlated with the energy of the laser beam. Therefore, by acquiring the correlation, the accurate energy of the processing laser beam including a high-frequency laser beam can be indirectly acquired. As a result, even when processing using a processing laser beam including a high-frequency laser beam, a processing defect can be accurately determined based on the energy of the laser beam during processing.

[0009] In the laser processing apparatus according to the first aspect, preferably, the control unit sets a predetermined threshold value for the light intensity correspondence value based on the correlation between the energy of the low-frequency laser beam and the first light intensity correspondence value, and when processing with the processing laser beam including the high-frequency laser beam, determines that processing corresponding to a second light intensity correspondence value that is less than the predetermined threshold value is defective. With this configuration, it can be determined that processing corresponding to a second light intensity correspondence value that is less than the predetermined threshold value is defective processing due to insufficient energy, so that processing defects due to insufficient energy, which are relatively likely to occur, can be efficiently determined.

[0010] In the laser processing apparatus according to the first aspect, the control unit is preferably configured to acquire the correlation based on an average value of the energies of the plurality of low-frequency laser beams and an average value of the plurality of first light intensity correspondence values. This configuration can suppress variations in the correlation due to variations in the energies of the low-frequency laser beams and the first light intensity correspondence values. As a result, the accuracy of determining processing defects can be improved.

[0011] In the laser processing apparatus according to the first aspect, the light intensity acquisition unit is preferably a photodetector. With this configuration, the light intensity corresponding value can be acquired by a photodetector, which is relatively easy to obtain.

[0012] In the laser processing device that determines that processing corresponding to the second light intensity correspondence value that is less than the predetermined threshold is defective, the control unit is preferably configured to acquire defective processing coordinates, which are the coordinates of the processing position determined to be defective, based on the result of the determination when processing with the processing laser light including the high-frequency laser light and the coordinates of the processing position. With this configuration, the defective processing coordinates can be acquired automatically, so that the time required to acquire the defective processing coordinates (identify the defective processing location) can be reduced.

[0013] In this case, preferably, the control unit controls the laser beam irradiation unit to irradiate the laser beam to the defective processing coordinates when processing with the processing laser beam including the high-frequency laser beam, thereby performing reprocessing. With this configuration, the object at the defective processing coordinates can be automatically reprocessed, thereby reducing the time required for reprocessing the object at the defective processing coordinates and the processing effort required by the operator.

[0014] In the laser processing apparatus according to the first aspect, the low-frequency laser beam is preferably less than 25 kHz, and the high-frequency laser beam is preferably 25 kHz or higher. In this way, even when processing is performed using a processing laser beam including a high-frequency laser beam having a particularly high frequency of 25 kHz or higher, processing defects can be accurately determined based on the energy of the laser beam during processing.

[0015] In the laser processing apparatus according to the first aspect, the control unit is preferably configured to switch between a first state in which a processing defect is determined based on the correlation and the second light intensity correspondence value when processing with a processing laser beam including a high-frequency laser beam, and a second state in which a processing defect is determined based on the energy of the low-frequency laser beam acquired by the energy measurement unit when processing with a low-frequency laser beam. With this configuration, the energy of the processing laser beam can be directly acquired when processing with a low-frequency laser beam. As a result, even when processing with a low-frequency laser beam, a processing defect can be more accurately determined and control of the judgment process can be simplified compared to when the energy of the processing laser beam is indirectly acquired based on the correlation and the second light intensity correspondence value.

[0016] A laser processing method according to a second aspect of the present invention includes an energy measurement step of acquiring energy of low-frequency laser light having a frequency lower than a predetermined frequency from among laser light irradiated from a laser light irradiating unit and used to process an object; a first light intensity acquisition step of acquiring a first light intensity correspondence value which is a value corresponding to the intensity of the low-frequency laser light when acquiring the energy of the low-frequency laser light in the energy measurement step; a second light intensity acquisition step of acquiring a second light intensity correspondence value which is a value corresponding to the intensity of processing laser light including high-frequency laser light having a frequency equal to or higher than a predetermined frequency from among laser light irradiated from the laser light irradiating unit; a correlation acquisition step of acquiring a correlation between the energy of the low-frequency laser light and the first light intensity correspondence value; and a determination step of determining processing defects when processing with processing laser light including high-frequency laser light based on the acquired correlation and the second light intensity correspondence value.

[0017] In the laser processing method according to the second aspect, as described above, a correlation between the energy of the low-frequency laser beam and a first light intensity correspondence value, which is a value corresponding to the intensity of the low-frequency laser beam, is acquired, and a processing defect is determined when processing is performed using a processing laser beam including a high-frequency laser beam based on the acquired correlation and a second light intensity correspondence value, which is a value corresponding to the intensity of the processing laser beam including a high-frequency laser beam. This makes it possible to indirectly acquire the positive energy of the processing laser beam including a high-frequency laser beam. As a result, it is possible to provide a laser processing method that can accurately determine a processing defect based on the energy of the laser beam during processing, even when processing is performed using a processing laser beam including a high-frequency laser beam.

[0018] As described above, the laser processing apparatus and laser processing method of the present invention can accurately determine processing defects based on the energy of the laser light during processing, even when processing is performed using processing laser light including high-frequency laser light.

[0019] FIG. 1 is a schematic diagram showing the overall configuration of a laser processing apparatus when processing an object according to one embodiment of the present invention. FIG. 2 is a plan view showing an object on a wafer according to one embodiment of the present invention. FIG. 3 is a part of a flowchart for explaining the processing of a laser processing method according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing the state of a laser processing apparatus when irradiating low-frequency laser light according to one embodiment of the present invention. FIG. 5 is a graph showing the energy of low-frequency laser light acquired by an energy measurement unit according to one embodiment of the present invention. FIG. 6 is a graph showing light intensity correspondence values ​​of low-frequency laser light acquired by a light intensity acquisition unit according to one embodiment of the present invention. FIG. 7 is a graph for explaining lower and upper limit values ​​of light intensity correspondence values ​​that are determined to be good processing according to one embodiment of the present invention. FIG. 8 is a diagram for explaining processing positions and processing order according to one embodiment of the present invention. FIG. 9 is a graph showing light intensity correspondence values ​​of processing laser light including high-frequency laser light acquired by a light intensity acquisition unit according to one embodiment of the present invention. FIG. 10 is a part of a flowchart for explaining the processing of a laser processing method according to one embodiment of the present invention. FIG. 11 is a graph showing the energy of processing laser light acquired by an energy measurement unit when processing is performed with low-frequency laser light according to one embodiment of the present invention.

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] [Embodiment] (Configuration of Laser Processing Apparatus) The configuration of a laser processing apparatus 100 according to one embodiment of the present invention will be described with reference to Figs. 1 and 2 .

[0022] As shown in Figures 1 and 2, the laser processing apparatus 100 is an apparatus for processing an object on a wafer 1 by irradiating it with laser light. For example, the laser processing apparatus 100 is an apparatus for processing a wiring pattern 2 on the wafer 1 by irradiating it with processing laser light LW at a processing position P. The wiring pattern 2 is, for example, a fuse. Processing may be, for example, blowing the fuse. The processing position P may be, for example, the center of gravity of the wiring pattern 2. The wiring pattern 2 is an example of an "object" in the claims.

[0023] As shown in FIG. 1 , the laser processing apparatus 100 includes a laser beam irradiation unit 10, a mirror 11, a mirror 12, an energy meter 20, a photodetector 30, a stage 40, a moving mechanism 41, a damper 42, and a control unit 60. In FIG. 1 , the left-right direction (one direction in a horizontal plane) of the laser processing apparatus 100 is defined as the X direction. The up-down direction (vertical direction) of the laser processing apparatus 100 is defined as the Z direction. The direction perpendicular to the X and Z directions of the laser processing apparatus 100 (the other direction in a horizontal plane) is defined as the Y direction. In the following description, one side of the X direction is defined as the X1 direction, and the other side is defined as the X2 direction. The back side of the Y direction in FIG. 1 is defined as the Y2 direction, and the front side is defined as the Y1 direction. In the Z direction, the direction of increasing height is defined as the Z1 direction, and the direction of decreasing height is defined as the Z2 direction. The energy meter 20 is an example of an "energy measurement unit" in the claims. The photodetector 30 is an example of the "light intensity acquisition unit" in the claims.

[0024] The laser light irradiation unit 10 is a light source that emits laser light with a near-infrared wavelength, for example, a wavelength of 780 nm or more and less than 2500 nm. When processing the wiring pattern 2, the laser light irradiation unit 10 is controlled by the control unit 80 to irradiate the wiring pattern 2 on the wafer 1 with processing laser light LW, which includes high-frequency laser light of 25 kHz or more, among the laser lights that the laser light irradiation unit 10 can irradiate. When processing an object other than the wiring pattern 2, the object on the wafer 1 may be irradiated with low-frequency laser light LT of less than 25 kHz among the laser lights that the laser light irradiation unit 10 can irradiate. The spot diameter of the processing laser light LW irradiated by the laser light irradiation unit 10 on the wiring pattern 2 is, for example, 3 μm.

[0025] The mirrors 11 and 12 are configured to reflect a portion of the incident light and transmit the remainder. As a result, the processing laser light LW irradiated by the laser light irradiating unit 10 is split into a processing laser light LW2 reflected by the mirror 11 and a processing laser light LW1 transmitted through the mirror 11. The processing laser light LW1 transmitted through the mirror 11 is then split into a processing laser light LW4 reflected by the mirror 12 and a processing laser light LW3 transmitted through the mirror 12. In this embodiment, the positions and angles of the laser light irradiating unit 10, the mirror 11, and the mirror 12 are fixed. The mirror 11, for example, reflects 10% of the incident light and transmits the remaining 90%. The mirror 12, for example, reflects 99% of the incident light and transmits the remaining 1%. The reflection and transmission ratios of the mirrors 11 and 12 are determined so that the energy meter 20 and the photodetector 30 function without being damaged.

[0026] The energy meter 20 is configured to measure the energy of incident light. In this embodiment, the energy meter 20 is arranged so that the laser light reflected by the mirror 11 is incident thereon. When processing the wiring pattern 2, the processing laser light LW2 is incident on the energy meter 20. Note that the energy meter 20 cannot accurately measure the energy of high-frequency laser light of 25 kHz or more. In other words, the energy meter 20 cannot accurately measure the energy of the processing laser light LW2, which includes high-frequency laser light of 25 kHz or more and is incident when processing the wiring pattern 2. For example, a "PE10-C" manufactured by Ophir is used as the energy meter 20.

[0027] The photodetector 30 is configured to acquire a value corresponding to the intensity of incident light (light intensity correspondence value). The light intensity correspondence value is, for example, an electrical signal such as a current or voltage that is correlated with light intensity. Here, since light intensity is correlated with light energy, the light intensity correspondence value is correlated with light energy. Specifically, the light intensity correspondence value is proportional to light energy. In this embodiment, the photodetector 30 is positioned so that laser light transmitted through the mirror 12 is incident on the photodetector 30. When processing the wiring pattern 2, a processing laser light LW3 is incident on the photodetector 30. Note that the photodetector 30 can accurately acquire the light intensity correspondence value of the laser light regardless of the frequency of the laser light. In other words, the photodetector 30 can accurately measure the light intensity correspondence value of the processing laser light LW3, which includes high-frequency laser light of 25 kHz or more, that is incident when processing the wiring pattern 2. For example, a "PDA05CF2" manufactured by THORLABS is used as the photodetector 30.

[0028] The stage 40 is capable of placing the wafer 1 on a flat top plate (the surface on the Z1 side). The stage 40 includes a moving mechanism 41 and a damper 42. The damper 42 is fixed to the side of the stage 40, for example, by a fastening member (not shown). The moving mechanism 41 is configured to be able to move the stage 40 at least in the X and Y directions by being controlled by the control unit 60. As a result, the moving mechanism 41 controlled by the control unit 60 moves the relative position between the laser light emitted by the laser light irradiation unit 10 and the stage 40. For example, when processing the wiring pattern 2, the relative position between the processing laser light LW4 and the wafer 1 placed on the top plate of the stage 40 is moved, so that the processing laser light LW4 can be irradiated at an arbitrary processing position P (see FIG. 2 ).

[0029] The damper 42 is intended to receive laser light irradiated for purposes other than processing the target object, so that the laser processing apparatus 100 and the wafer 1 are not damaged by the laser light irradiated by the laser light irradiating unit 10. When processing the wiring pattern 2, the processing laser light LW is not irradiated onto the damper 42. The damper 42 is configured so as not to transmit the received laser light. The damper 42 is, for example, an iron plate.

[0030] The control unit 60 includes, for example, a processor such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a GPU (Graphics Processing Unit). The control unit 60 is configured to execute a program (software) to perform various controls of the laser light irradiation unit 10, the energy meter 20, the photodetector 30, and the movement mechanism 41 in accordance with a laser processing process flow (see FIGS. 3 and 10) described below. Details of the control performed by the control unit 60 will be described later.

[0031] (Laser Processing Method) Next, a laser processing method according to one embodiment of the present invention will be described with reference to FIGS.

[0032] As shown in Fig. 3, in step S1, the control unit 60 (see Fig. 1) determines whether the processing laser light includes high-frequency laser light. If the determination is Yes, the process proceeds to step S2, and if the determination is No, the process proceeds to step S10 (see Fig. 10). Specifically, the control unit 60 determines whether the processing laser light includes high-frequency laser light based on processing conditions that are set in advance and include information about the frequency of the processing laser light. In this embodiment, the determination is Yes when processing the wiring pattern 2. Below, the processing when the determination is Yes will be described first.

[0033] In step S2, the control unit 60 (see FIG. 1) moves the stage 40 to a position where the laser light is irradiated onto the damper 42. Specifically, as shown in FIG. 4, the control unit 60 controls the movement mechanism 41 to move the stage 40 to a position where the laser light can be irradiated onto the damper 42. Note that at the time of step S2, the laser light irradiation unit 10 is not irradiating the laser light.

[0034] Returning to FIG. 3 , in step S3, the control unit 60 (see FIG. 1 ) causes the laser light irradiation unit 10 to irradiate the damper 42 with low-frequency laser light LT of less than 25 kHz, as shown in FIG. 4 . It is preferable that the low-frequency laser light LT irradiated in step S3 has a single frequency. The low-frequency laser light LT irradiated by the laser light irradiation unit 10 is branched into low-frequency laser light LT2 reflected by the mirror 11 and low-frequency laser light LT1 transmitted through the mirror 11. The low-frequency laser light LT1 transmitted through the mirror 11 is then branched into low-frequency laser light LT4 reflected by the mirror 12 and low-frequency laser light LT3 transmitted through the mirror 12. The low-frequency laser beam LT2 reflected by the mirror 11 is incident on the energy meter 20, and the low-frequency laser beam LT3 transmitted by the mirror 12 is incident on the photodetector 30, and the low-frequency laser beam LT4 reflected by the mirror 12 is irradiated onto the damper 42. Here, the energy meter 20 can accurately measure the energy of the low-frequency laser beam LT2. Furthermore, the photodetector 30 can accurately measure a value corresponding to the intensity of the low-frequency laser beam LT3. Note that the energy per unit frequency of the low-frequency laser beam LT irradiated in step S3 is the same as the energy per unit frequency of the processing laser beam LW irradiated when processing the wiring pattern 2 and capable of processing the wiring pattern 2 well.

[0035] Returning to Fig. 3, in step S4, the control unit 60 (see Fig. 1) acquires the energy of the low-frequency laser light LT. Specifically, as shown in Figs. 4 and 5, the control unit 60 acquires and stores an average energy A, which is the average value of the energy TE of the low-frequency laser light LT2 measured by the energy meter 20 for 10 consecutive measurements. The energy TE is an example of the "energy of low-frequency laser light" in the claims. The average energy A is an example of the "average value of the energy of low-frequency laser light" in the claims.

[0036] Returning to FIG. 3 , in step S5, the control unit 60 (see FIG. 1 ) acquires a light intensity correspondence value of the low-frequency laser light LT. Note that steps S4 and S5 are both initiated after completion of step S3. Specifically, as shown in FIGS. 4 and 6 , the control unit 60 acquires an average light intensity correspondence value B, which is the average value of the light intensity correspondence values ​​TN of 10 consecutive low-frequency laser light LT3 measured by the photodetector 30. Note that the 10 consecutive low-frequency laser light LT3 and the 10 consecutive low-frequency laser light LT2 in step S4 are each based on low-frequency laser light LT emitted at the same timing. Note that the light intensity correspondence value TN is an example of a "first light intensity correspondence value" in the claims. Note that the average light intensity correspondence value B is an example of an "average value of the first light intensity correspondence values" in the claims.

[0037] Returning to Fig. 3, in step S6, the control unit 60 (see Fig. 1) moves the stage 40 to a position where the laser light is irradiated onto the object. Note that step S6 is started after both steps S4 and S5 are completed. Specifically, as shown in Figs. 1 and 2, the control unit 60 controls the movement mechanism 41 to move the stage 40 to a position where the laser light can be irradiated onto the processing position P of the wiring pattern 2 on the wafer 1 placed on the stage 40. Note that during this step S6, the laser light irradiation unit 10 does not irradiate the laser light.

[0038] Returning to FIG. 3 , in step S7, the control unit 60 (see FIG. 1 ) sets a satisfactory processing range for the light intensity correspondence value. Like step S6, step S7 is initiated after steps S4 and S5 are both completed. Specifically, as shown in FIGS. 5 to 7 , the control unit 60 calculates a satisfactory processing median C, which is a satisfactory light intensity correspondence value when processing the wiring pattern 2, based on the average energy A and the average light intensity correspondence value B. The calculation formula for the satisfactory processing median C is C = B × α / A, where α is the energy measured by the energy meter 20 when irradiating the wiring pattern 2 with laser light that can satisfactorily process the wiring pattern 2. In this embodiment, since the average energy A = the satisfactory energy α as described above, the satisfactory processing median C = the average light intensity correspondence value B. The control unit 60 then multiplies the good processing median C by 0.95 to calculate a good processing lower limit C1, and multiplies the good processing median C by 1.05 to calculate a good processing upper limit C2, and sets a good processing range CR that is equal to or greater than the good processing lower limit C1 and equal to or less than the good processing upper limit C2. The good processing median C is an example of the "relative relationship" in the claims. The good processing lower limit C1 is an example of the "predetermined threshold value" in the claims.

[0039] Returning to FIG. 3 , in step S8, the control unit 60 (see FIG. 1 ) acquires a light intensity correspondence value of the processing laser beam LW while processing the object. Note that step S8 is started after completion of step S6. Specifically, as shown in FIGS. 1 , 8 , and 9 , the control unit 60 causes the moving mechanism 41 to move the irradiation position of the processing laser beam LW4 relative to the wafer 1 along the dashed arrowed line (see FIG. 8 ), and causes the laser beam irradiation unit 10 to irradiate the processing laser beam LW3 at a timing when the irradiation position of the processing laser beam LW4 coincides with a plurality of processing positions P on the wafer 1. Then, the control unit 60 acquires a processing light intensity correspondence value WN, which is a light intensity correspondence value of the processing laser beam LW3 measured by the photodetector 30, at the timing when the processing laser beam LW3 is irradiated. At this time, because the processing laser beam LW2 incident on the energy meter 20 includes high-frequency laser beams of 25 kHz or more, the energy meter 20 cannot accurately measure the energy of the incident laser beam. Here, the control unit 60 stores the coordinates of a plurality of preset processing positions P and the processing order thereof. Furthermore, the intervals between each of the plurality of processing positions P along the irradiation position of the processing laser light LW4 on the wafer 1 are non-uniform. Furthermore, the processing light intensity correspondence value WN is acquired in a number corresponding to the number of processing positions P on the wafer 1 (number of processing times). The processing light intensity correspondence value WN is an example of a "second light intensity correspondence value" in the claims.

[0040] Returning to FIG. 3 , in step S9, the control unit 60 (see FIG. 1 ) determines whether a processing defect exists based on the acceptable processing range CR and the light intensity correspondence value WN of the processing laser light LW. Note that step S9 is started after both steps S7 and S8 are completed. Specifically, as shown in FIG. 9 , the control unit 60 determines whether a processing defect exists when a processing defect exists corresponding to a processing light intensity correspondence value WN within the acceptable processing range CR, and whether a processing defect exists when a processing defect exists corresponding to a processing light intensity correspondence value WN that is greater than the acceptable processing upper limit C2 or less than the acceptable processing lower limit C1. For example, the control unit 60 determines whether a processing defect exists when a processing defect exists corresponding to a processing light intensity correspondence value WND that is less than the acceptable processing lower limit C1.

[0041] (When processing is performed using low-frequency laser light LT) If the answer is No in step S1 (see FIG. 3), then in step S10, as shown in FIG. 10, the control unit 60 (see FIG. 1) moves the stage 40 to a position where the laser light is irradiated onto the object. The specific control is the same as in step S6. Note that steps S10 to S12 will be described, as an example, for the case where processing is performed using low-frequency laser light LT.

[0042] In step S11, the control unit 60 (see FIG. 1 ) acquires the energy of the processing laser light (low-frequency laser light LT) while processing the object. Specifically, as shown in FIGS. 4 , 8 , and 11 , the control unit 60 causes the moving mechanism 41 to relatively move the irradiation position of the processing laser light (low-frequency laser light LT) on the wafer 1 along the dashed arrowed line (see FIG. 8 ), and causes the laser light irradiation unit 10 to irradiate the processing laser light (low-frequency laser light LT) at a timing when the irradiation position of the processing laser light (low-frequency laser light LT) coincides with a plurality of processing positions P on the wafer 1. Then, the control unit 60 acquires the energy WE of the processing laser light (low-frequency laser light LT2) measured by the energy meter 20 at the timing when the processing laser light (low-frequency laser light LT) is irradiated. Here, the control unit 60 stores the coordinates of a plurality of pre-set processing positions P and the processing order thereof. The intervals between the plurality of processing positions P along the irradiation position of the processing laser light (low-frequency laser light LT) on the wafer 1 are non-uniform. The energy WE is acquired by the number corresponding to the number of processing positions P on the wafer 1 (the number of times of processing).

[0043] Returning to FIG. 10, in step S12, the control unit 60 (see FIG. 1) determines whether processing is defective based on the acceptable processing range and the energy of the processing laser light (low-frequency laser light LT). Specifically, as shown in FIG. 11, the control unit 60 determines whether processing is defective when the energy WE falls within the acceptable processing range ER, which is equal to or greater than a predetermined acceptable processing lower limit E1 and equal to or less than an acceptable processing upper limit E2. Processing is also determined to be defective when the energy WE is greater than the acceptable processing upper limit E2 or less than the acceptable processing lower limit E1. For example, the control unit 60 determines whether processing is defective when the energy WED is less than the acceptable processing lower limit E1. After step S12 is completed, the process proceeds to step S13 (see FIG. 3).

[0044] Returning to FIG. 3 , in step S13, the control unit 60 (see FIG. 1 ) performs reprocessing at the processing position determined to be defective. Note that step S13 is started after completion of either step S9 or step S12. Specifically, as shown in FIGS. 8 , 9 , and 11 , the control unit 60 performs reprocessing by causing the laser beam irradiation unit 10 (see FIG. 1 ) to irradiate the processing position PD of the processing corresponding to the processing light intensity correspondence value WND or energy WED determined to be defective in step S9 or step S12 with the processing laser beam LW or LT. Note that the reprocessing is performed for processing corresponding to a processing light intensity correspondence value WN or energy WE less than the processing-satisfactory lower limit C1 or E1, but is not performed for processing corresponding to a processing light intensity correspondence value WN or energy WE greater than the processing-satisfactory upper limit C2 or E2. This is because processing corresponding to a processing light intensity corresponding value WN or energy WE greater than the upper limit C2 or E2 for good processing is a processing defect caused by excessive energy, and reprocessing will not result in good processing. After step S13 is completed, the procedure for the laser processing method is completed. Note that steps S1 to S13 are performed for each wafer 1.

[0045] (Effects of the embodiment) Next, the effects of the present embodiment will be described.

[0046] In this embodiment, as described above, a correlation between the energy TE of the low-frequency laser beam LT and the light intensity correspondence value TN, which is a value corresponding to the intensity of the low-frequency laser beam LT, is acquired, and a processing defect is determined when processing is performed using the processing laser beam LW, which includes a high-frequency laser beam, based on the acquired correlation and the processing light intensity correspondence value WN, which is a value corresponding to the intensity of the processing laser beam LW, which includes a high-frequency laser beam. This makes it possible to indirectly acquire the accurate energy of the processing laser beam LW, which includes a high-frequency laser beam. As a result, even when processing is performed using the processing laser beam LW, which includes a high-frequency laser beam, a processing defect can be accurately determined based on the energy of the laser beam during processing.

[0047] In the present embodiment, as described above, the control unit 60 sets the good processing lower limit C1 of the light intensity correspondence value based on the correlation between the energy TE of the low-frequency laser beam LT and the light intensity correspondence value TN, and when processing is performed with the processing laser beam LW including the high-frequency laser beam, determines that processing corresponding to a processing light intensity correspondence value WN that is less than the good processing lower limit C1 is defective. As a result, processing corresponding to a processing light intensity correspondence value WN that is less than the good processing lower limit C1 can be determined to be defective processing due to insufficient energy, making it possible to efficiently determine processing defects due to insufficient energy, which are relatively likely to occur.

[0048] Furthermore, in this embodiment, as described above, the control unit 60 is configured to acquire the correlation based on the average energy A, which is the average value of the energies TE of the plurality of low-frequency laser beams LT, and the average light intensity correspondence value B, which is the average value of the plurality of light intensity correspondence values ​​TN. This makes it possible to suppress variations in the correlation caused by variations in the energies TE of the low-frequency laser beam LT and the light intensity correspondence values ​​TN. As a result, it is possible to improve the accuracy of determining processing defects.

[0049] Furthermore, in this embodiment, as described above, the photodetector 30 is used as the light intensity acquisition unit, so that the light intensity correspondence value can be acquired using a photodetector that is relatively easy to obtain.

[0050] Furthermore, in this embodiment, as described above, the control unit 60 is configured to acquire defective machining coordinates, which are the coordinates of the machining position PD determined to be defective machining, based on the result of the judgment when machining is performed with the processing laser light LW including the high-frequency laser light and the coordinates of the machining position P. This makes it possible to automatically acquire the defective machining coordinates, thereby reducing the time required to acquire the defective machining coordinates (to identify the defective machining location).

[0051] In the present embodiment, as described above, the control unit 60 controls the laser light irradiation unit 10 to irradiate the processing laser light LW including the high-frequency laser light onto the processing-defective coordinates when processing is performed using the processing laser light LW, thereby performing reprocessing. This allows the wiring pattern 2 at the processing-defective coordinates to be automatically reprocessed, thereby reducing the time required for reprocessing the wiring pattern 2 at the processing-defective coordinates and the processing effort required by the worker.

[0052] In this embodiment, as described above, the low-frequency laser light LT is less than 25 kHz, and the high-frequency laser light is 25 kHz or higher. Thus, even when processing is performed with the processing laser light LW including high-frequency laser light with a particularly high frequency, such as 25 kHz or higher, it is possible to accurately determine processing defects based on the energy of the laser light during processing.

[0053] Furthermore, in this embodiment, as described above, the control unit 60 is configured to be able to switch between a first state in which a processing defect is determined based on the correlation and the processing light intensity correspondence value WN when processing with the processing laser light LW including the high-frequency laser light, and a second state in which a processing defect is determined based on the energy WE of the low-frequency laser light LT acquired by the energy meter 20 when processing with the low-frequency laser light LT. This allows the energy of the processing laser light (low-frequency laser light LT) to be directly acquired when processing with the low-frequency laser light LT. As a result, even when processing with the low-frequency laser light LT, a processing defect can be more accurately determined and the control of the judgment process can be simplified compared to when the energy of the processing laser light (low-frequency laser light LT) is indirectly acquired based on the correlation and the processing light intensity correspondence value WN.

[0054] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications (modifications) within the meaning and scope of the claims.

[0055] For example, in this embodiment, an example has been shown in which a wiring pattern on a wafer is used as the object to be processed, but the present invention is not limited to this. For example, the object to be processed may be wiring that is not formed on a wafer, or an object made of resin or the like that can be processed by laser light. Furthermore, the wiring pattern may be a simple wiring pattern other than a fuse.

[0056] In the present embodiment, the processing light intensity corresponding value WN is determined to be defective when it is greater than the upper limit C2 or less than the lower limit C1. However, the present invention is not limited to this. For example, the processing light intensity corresponding value WN within a predetermined range may be determined to be defective.

[0057] In addition, in the present embodiment, an example has been shown in which the good processing median value C is calculated based on the average energy A, which is the average value of the energies TE of the plurality of low-frequency laser beams LT, and the average light intensity correspondence value B, which is the average value of the plurality of light intensity correspondence values ​​TN, but the present invention is not limited to this. For example, the good processing median value C may be calculated based on any one of the energies TE of the plurality of low-frequency laser beams LT and any one of the plurality of light intensity correspondence values ​​TN.

[0058] Although the present embodiment illustrates an example in which a photodetector is used as the light intensity acquisition unit, the present invention is not limited to this. For example, any measuring device may be used as long as it can acquire a value that correlates with the energy of high-frequency laser light of 25 kHz or higher. For example, a beam profiler that can acquire the intensity profile of laser light may be used as the light intensity acquisition unit.

[0059] In the present embodiment, the control unit 60 acquires the defective machining coordinates, which are the coordinates of the machining position PD determined to be defective, based on the result of the determination when machining is performed with the machining laser light LW including the high-frequency laser light and the coordinates of the machining position P. However, the present invention is not limited to this. For example, the control unit 60 does not need to acquire the defective machining coordinates, which are the coordinates of the machining position PD determined to be defective.

[0060] In the present embodiment, the control unit 60 controls the laser light irradiation unit 10 to irradiate the defective processing coordinates with the laser light to perform reprocessing, but the present invention is not limited to this. For example, the control unit 60 does not need to control reprocessing.

[0061] In addition, in the present embodiment, an example has been shown in which the low-frequency laser light LT is less than 25 kHz and the high-frequency laser light is 25 kHz or more, but the present invention is not limited to this. For example, the frequency that is the boundary between the low-frequency laser light LT and the high-frequency laser light may be other than 25 kHz.

[0062] In addition, in the present embodiment, the control unit 60 is configured to be able to switch between a first state in which a processing defect is determined based on the correlation and the processing light intensity correspondence value WN when processing is performed with the processing laser light LW including the high-frequency laser light, and a second state in which a processing defect is determined based on the energy WE of the low-frequency laser light LT acquired by the energy meter 20 when processing is performed with the low-frequency laser light LT, but the present invention is not limited to this. For example, a processing defect may also be determined based on the correlation and the processing light intensity correspondence value WN when processing is performed with the low-frequency laser light LT.

[0063] In the present embodiment, the position of the mirror 11 is fixed, but the present invention is not limited to this. For example, when processing is performed using the processing laser light LW including high-frequency laser light, the mirror 11 may be moved so that the processing laser light LW is not irradiated onto the mirror 11.

[0064] Furthermore, in the present embodiment, an example has been shown in which the energy per unit frequency of the low-frequency laser light LT irradiated in step S3 is the same as the energy per unit frequency of the processing laser light LW that is irradiated when processing the wiring pattern 2 and can satisfactorily process the wiring pattern 2, but the present invention is not limited to this. For example, the energy per unit frequency of the low-frequency laser light LT irradiated in step S3 may be different from the energy per unit frequency of the processing laser light LW that is irradiated when processing the wiring pattern 2 and can satisfactorily process the wiring pattern 2.

[0065] In the present embodiment, the control unit 60 performs reprocessing by causing the laser light irradiation unit 10 (see FIG. 1) to irradiate the processing position PD of the processing corresponding to the processing light intensity corresponding value WND or energy WED determined to be a processing defect in step S9 or step S12 with the processing laser light LW or LT, but the present invention is not limited to this. For example, reprocessing may be performed using a laser light having an energy smaller than that of the processing laser light LW or LT.

[0066] In addition, in the present embodiment, an example is shown in which the good processing median value C is multiplied by 0.95 to calculate the good processing lower limit value C1, and the good processing upper limit value C2 is multiplied by 1.05 to calculate the good processing median value C, but the present invention is not limited to this. For example, the good processing lower limit value C1 and the good processing upper limit value C2 may be any number of times the good processing median value C, or may be calculated by adding or subtracting a certain value from the good processing median value C.

[0067] In addition, in the present embodiment, an example has been shown in which the control unit 60 controls the moving mechanism 41 to move the stage 40 in step S2 so that the laser light irradiated by the laser light irradiating unit 10 hits the damper 42, but the present invention is not limited to this. For example, if the irradiated laser light will not damage the laser processing apparatus 100 and the wafer 1, step S3 may be started without moving the stage 40 (without performing step S2).

[0068] In addition, in the present embodiment, an example is shown in which the procedure of the laser processing method is terminated after reprocessing is performed in step S13, but the present invention is not limited to this. For example, after reprocessing is performed, the result of the reprocessing may be determined based on the light intensity correspondence value or energy acquired during the reprocessing.

[0069] In addition, in the present embodiment, an example has been shown in which 10 consecutive data sets are acquired when acquiring the energy and light intensity correspondence value of the low-frequency laser light LT, but the present invention is not limited to this. For example, 10 non-consecutive data sets may be acquired. Also, for example, multiple data sets other than 10 may be acquired. Also, for example, one data set may be acquired.

[0070] 2 Wiring pattern (target object) 10 Laser light irradiation unit 20 Energy meter (energy measurement unit) 30 Photodetector (light intensity acquisition unit) 60 Control unit 100 Laser processing device P Processing position LW Processing laser light including high-frequency laser light LT Low-frequency laser light TE Energy TN Light intensity correspondence value (first light intensity correspondence value) C Good processing median value (relative relationship) C1 Good processing lower limit value (predetermined threshold value) WN Light intensity correspondence value (second light intensity correspondence value)

Claims

1. A laser processing device comprising: a laser light irradiating unit that irradiates a laser light to process an object; an energy measuring unit that acquires the energy of low-frequency laser light that is lower than a predetermined frequency from the laser light irradiated from the laser light irradiating unit; a light intensity acquiring unit that acquires a first light intensity correspondence value that is a value corresponding to the intensity of the low-frequency laser light when the energy measuring unit acquires the energy of the low-frequency laser light, and acquires a second light intensity correspondence value that is a value corresponding to the intensity of processing laser light that includes high-frequency laser light that is higher than the predetermined frequency from the laser light irradiated from the laser light irradiating unit; and a control unit that acquires a correlation between the energy of the low-frequency laser light and the first light intensity correspondence value, and determines processing defects when processing with the processing laser light including the high-frequency laser light based on the acquired correlation and the second light intensity correspondence value.

2. The laser processing device of claim 1, wherein the control unit sets a predetermined threshold value for the light intensity correspondence value based on the correlation between the energy of the low-frequency laser light and the first light intensity correspondence value, and when processing using the processing laser light including the high-frequency laser light, determines that processing corresponding to the second light intensity correspondence value that is less than the predetermined threshold value is defective processing.

3. The laser processing device of claim 1, wherein the control unit is configured to acquire the correlation based on the average value of the energy of the plurality of low-frequency laser beams and the average value of the plurality of first light intensity correspondence values.

4. The laser processing device according to claim 1, wherein the light intensity acquisition unit is a photodetector.

5. The laser processing device according to claim 2, wherein the control unit is configured to acquire defective processing coordinates, which are the coordinates of a processing position determined to be defective processing, based on the result of the judgment when processing using the processing laser light including the high-frequency laser light and the coordinates of the processing position.

6. The laser processing device according to claim 5, wherein the control unit controls the laser light irradiation unit to irradiate the laser light onto the defective processing coordinates when processing with the processing laser light including the high-frequency laser light, thereby performing reprocessing.

7. The laser processing device according to claim 1, wherein the low frequency laser light is less than 25 kHz and the high frequency laser light is 25 kHz or higher.

8. The laser processing device according to claim 1, wherein the control unit is configured to be able to switch between a first state in which processing defects are determined based on the correlation and the second light intensity correspondence value when processing is performed with the processing laser light including the high-frequency laser light, and a second state in which processing defects are determined based on the energy of the low-frequency laser light acquired by the energy measuring unit when processing is performed with the low-frequency laser light.

9. A laser processing method comprising: an energy measuring step of acquiring energy of low-frequency laser light having a frequency lower than a predetermined frequency from among laser light irradiated from a laser light irradiating unit and used to process an object; a first light intensity acquiring step of acquiring a first light intensity corresponding value which is a value corresponding to the intensity of the low-frequency laser light when acquiring the energy of the low-frequency laser light in the energy measuring step; a second light intensity acquiring step of acquiring a second light intensity corresponding value which is a value corresponding to the intensity of processing laser light including high-frequency laser light having a frequency equal to or higher than the predetermined frequency from among the laser light irradiated from the laser light irradiating unit; a correlation acquiring step of acquiring a correlation between the energy of the low-frequency laser light and the first light intensity corresponding value; and a determination step of determining processing defects when processing with the processing laser light including the high-frequency laser light based on the acquired correlation and the second light intensity corresponding value.

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