WO2013054445A1

WO2013054445A1 - Laser processing control device and laser processing control method

Info

Publication number: WO2013054445A1
Application number: PCT/JP2011/073694
Authority: WO
Inventors: 伊藤　健治; 正史成瀬; 智彦石塚; 悌史 ▲高▼橋
Original assignee: 三菱電機株式会社
Priority date: 2011-10-14
Filing date: 2011-10-14
Publication date: 2013-04-18
Also published as: TW201315562A

Abstract

A laser processing control device equipped with: a pulse detection unit (21) that detects the emission timing of a pulse laser emitted from a laser oscillator toward a substrate to be processed; an integration unit (23) that calculates an integrated energy amount by integrating each energy amount of the pulse laser emitted within a prescribed period of time; a correction amount calculation unit (25) that calculates a positional deviation correction amount in accordance with the integrated energy value, as a correction amount for correcting the irradiation position of the pulse laser to the desired position, when a positional deviation occurs in the pulse laser emitted toward the substrate to be processed; and a control unit which, with respect to a processing unit that processes the substrate to be processed using the pulse laser, performs control so as to correct the irradiation position of the pulse laser on the basis of the positional deviation correction amount.

Description

Laser processing control apparatus and laser processing control method

The present invention relates to a laser processing control apparatus and a laser processing control method for controlling a laser beam irradiation position on a substrate to be processed.

A laser processing apparatus for drilling a printed wiring board is equipped with, for example, a galvano scanner and an fθ lens. In such a laser processing apparatus, a part of the fθ lens is absorbed at the time of laser propagation, and the temperature of the fθ lens rises. Since the refractive index of the fθ lens changes as the temperature rises, the laser light is refracted by the fθ lens, and the irradiation position of the laser light changes. Therefore, it is common to measure the temperature of the fθ lens and correct the laser irradiation position by a galvano scanner based on the temperature.

For example, in the laser processing apparatus of Patent Document 1, a temperature sensor is installed on the side surface of the fθ lens, and the laser light irradiation position is corrected by a galvano scanner based on the temperature measured by the temperature sensor.

JP 2003-290944 A

However, in the above conventional technique, since the measurement position by the temperature sensor is the end of the fθ lens, it is difficult to instantaneously and accurately measure the temperature of the central portion of the fθ lens due to the influence of heat conduction or the like. This is because there is a time difference in the measured temperature due to heat conduction in the fθ lens. For this reason, there has been a problem that the correction of the irradiation position based on the measured temperature at the end of the fθ lens is not sufficient as a countermeasure for the positional deviation.

The present invention has been made in view of the above, and an object thereof is to obtain a laser processing control apparatus and a laser processing control method capable of accurately correcting the irradiation position of a laser beam.

In order to solve the above-described problems and achieve the object, the present invention provides a pulse detector that detects the emission timing of a pulse laser emitted from a laser oscillator to the substrate to be processed, and the pulse emitted within a predetermined time. An integration unit that integrates each energy amount of the laser to calculate an energy integration amount, and a correction that corrects the irradiation position of the pulse laser to a desired position when a positional deviation occurs in the pulse laser irradiated to the substrate to be processed As a quantity, a correction amount calculation unit that calculates a positional deviation correction amount according to the energy integrated amount, and a processing unit that processes the substrate to be processed using the pulse laser, based on the positional deviation correction amount, And a control unit that controls to correct the irradiation position of the pulse laser.

According to the present invention, since the irradiation position of the pulse laser is corrected by the positional deviation correction amount according to the integrated energy amount of the pulse laser emitted within a predetermined time, it is possible to accurately correct the irradiation position of the laser beam. Has the effect of becoming.

FIG. 1 is a diagram illustrating a configuration of a laser processing apparatus according to an embodiment. FIG. 2 is a block diagram illustrating a configuration of the position correction amount calculation apparatus. FIG. 3 is a flowchart showing a processing procedure of the laser processing according to the embodiment. FIG. 4 is a diagram for explaining control of the galvano mechanism by the position correction amount calculation device. FIG. 5 is a diagram illustrating the relationship between the rising temperature of the fθ lens and the amount of displacement. FIG. 6 is a diagram illustrating a relationship between a passing position of the laser light on the fθ lens and a positional deviation correction amount. FIG. 7 is a diagram for explaining misalignment and misalignment correction. FIG. 8 is a diagram illustrating a relationship between an actual temperature change of the fθ lens and a temperature detected by the temperature detection unit. FIG. 9 is a diagram for explaining a method of calculating the energy integration amount. FIG. 10 is a diagram for explaining a change in the amount of misalignment when the waiting time is set short. FIG. 11 is a diagram for explaining a change in the amount of misalignment when a long waiting time is set.

Hereinafter, a laser processing control device and a laser processing control method according to an embodiment of the present invention will be described in detail based on the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a diagram illustrating a configuration of a laser processing apparatus according to an embodiment. The laser processing apparatus 100 is an apparatus that performs laser drilling on a substrate (workpiece) 4 that is a substrate to be processed by irradiating a laser beam L (pulse laser beam). The laser processing apparatus 100 according to the present embodiment performs laser drilling on the substrate 4 while correcting the positional deviation of the laser light irradiation position caused by the temperature rise of the fθ lens 34 or the like.

The laser processing apparatus 100 includes a laser oscillator 1 that oscillates a laser beam L, a laser processing unit 3 that performs laser processing on the substrate 4, and a laser processing control apparatus 2. The laser oscillator 1 oscillates the laser beam L and sends it to the laser processing unit 3.

The laser processing unit 3 includes

galvanometer mirrors

35X and 35Y,

galvanometer scanners

36X and 36Y, an fθ lens (condensing lens) 34, an XY table (processing table) 32, and a temperature detection unit (temperature sensor) 38.

The

galvano scanners

36X and 36Y have a function of moving the irradiation position on the substrate 4 by changing the trajectory of the laser beam L, and the laser beam L is placed in each processing area (galvano area) set on the substrate 4. Scan two-dimensionally. The

galvano scanners

36X and 36Y rotate the

galvanometer mirrors

35X and 35Y to a predetermined angle in order to scan the laser light L in the XY direction.

Galvano

mirrors

35X and 35Y reflect the laser beam L and deflect it at a predetermined angle. The galvanometer mirror 35X deflects the laser beam L in the X direction, and the galvanometer mirror 35Y deflects the laser beam L in the Y direction.

The fθ lens 34 is a lens having telecentricity. The fθ lens 34 deflects the laser light L in a direction perpendicular to the main surface of the substrate 4 and condenses (irradiates) the laser light L at a processing position (hole position Hx) of the substrate 4.

The substrate 4 is a processing object such as a printed wiring board, and drilling is performed at a plurality of locations. The substrate 4 has, for example, a three-layer structure of copper foil (conductor layer), resin (insulating layer), and copper foil (conductor layer).

The XY table 32 places the substrate 4 and moves in the XY plane by driving a motor (not shown). As a result, the XY table 32 moves the substrate 4 in the in-plane direction.

The galvano area (scan area) is a range (scannable area) in which laser processing is possible by the operation of the galvano mechanism (

galvano scanners

36X and 36Y,

galvano mirrors

35X and 35Y) without moving the XY table 32. In the laser processing apparatus 100, after the XY table 32 is moved in the XY plane, the laser light L is two-dimensionally scanned by the

galvano scanners

36X and 36Y. The XY table 32 moves in order so that the center of each galvano area is directly below the center of the fθ lens 34 (galvano origin). The galvano mechanism operates so that each hole position Hx set in the galvano area becomes an irradiation position of the laser light L in order. Movement between the galvano areas by the XY table 32 and two-dimensional scanning of the laser light L in the galvano area by the galvano mechanism are sequentially performed in the substrate 4. Thereby, all hole positions Hx in the substrate 4 are laser processed.

The temperature detection unit 38 is disposed at the end (outer periphery) of the fθ lens 34, measures the base temperature of the fθ lens 34, and sends the measurement result to the position correction amount calculation device 20. The temperature detection unit 38 may be either a contact type or a non-contact type.

The laser processing control device 2 is connected to the laser oscillator 1 and the laser processing unit 3 (not shown), and controls the laser oscillator 1 and the laser processing unit 3. When laser processing the substrate 4, the laser processing control device 2 instructs the laser oscillator 1 and the laser processing unit 3 on the laser processing conditions set in the processing program. The laser processing conditions here include the pulse emission timing of the laser beam L, the laser beam irradiation position (coordinate values on the substrate 4), and the like.

The laser processing control device 2 according to the present embodiment includes a position correction amount calculation device 20 and a control unit 30. The position correction amount calculation device 20 calculates the correction amount (position shift correction amount) of the laser light irradiation position based on the energy amount (for example, the total value) of the laser light L applied to the substrate 4 within the latest predetermined time. It is a device to calculate. The position correction amount calculation device 20 outputs instruction information (position shift correction amount) to the galvano mechanism to the control unit 30 so that the laser beam L is irradiated to a desired position on the substrate 4.

The control unit 30 controls the operation of the galvano mechanism and the like based on the machining program, and corrects the operation of the galvano mechanism based on the instruction information from the position correction amount calculation device 20. The control unit 30 controls and corrects the laser light irradiation position by controlling and correcting the operation of the galvano mechanism.

In the laser processing apparatus 100, when the substrate 4 is irradiated with the laser light L, the temperature of the fθ lens 34 increases. When a temperature gradient is generated in the fθ lens 34, the laser beam irradiation position on the substrate 4 is shifted from the desired position. For this reason, in this embodiment, a positional deviation correction amount corresponding to the temperature gradient of the fθ lens 34 is calculated in advance, and the laser beam irradiation position is corrected using this positional deviation correction amount.

The temperature gradient of the fθ lens 34 changes, for example, according to the energy integrated amount of the laser light L irradiated to the substrate 4 within a predetermined time. For this reason, the relationship (correction coefficient etc.) between the energy integrated amount and the positional deviation correction amount is derived in advance. When performing laser processing, the position correction amount calculation device 20 calculates the integrated energy amount of the laser light L irradiated to the substrate 4 within a predetermined time. Further, the position correction amount calculation device 20 calculates a position shift correction amount using the correction coefficient and the calculated energy integration amount, and corrects the laser beam irradiation position using the position shift correction amount to the control unit 30. Let it be done.

The positional deviation of the irradiation position of the laser light L occurs due to a temperature gradient in the fθ lens 34, but the correction coefficient may be set without measuring the temperature gradient in the fθ lens 34. In this case, an actual positional deviation amount corresponding to the energy integration amount is measured, and a correction coefficient is set based on the measurement result. In other words, a relationship between the energy integration amount and the positional deviation amount is derived, and a correction coefficient is set based on the derived relationship.

When the correction coefficient is set based on the temperature gradient in the fθ lens 34, the temperature gradient in the fθ lens 34 is actually measured during laser processing. Then, a relationship between the temperature gradient and the energy integration amount is derived, and a relationship between the temperature gradient and the actual positional deviation amount is derived. Based on these derivation results, a relationship between the positional deviation amount and the energy integration amount is derived, and a correction coefficient is set based on the derivation results.

In the present embodiment, correction is made for each combination of the base temperature of the fθ lens 34 (hereinafter referred to as the lens temperature) and the irradiation position of the laser light L (coordinate values in the galvano area) (hereinafter referred to as the galvano coordinates). Set the coefficient.

The laser processing control device 2 is configured by a computer or the like, and controls the laser oscillator 1 and the laser processing unit 3 by NC (Numerical Control) control or the like. The laser processing control device 2 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. When the laser processing control device 2 controls the laser oscillator 1 or the laser processing unit 3, the CPU reads a processing program stored in the ROM by an input from an input unit (not shown) by the user. Various processes are executed by expanding the program storage area in the RAM. Various data generated during this processing is temporarily stored in a data storage area formed in the RAM. Thereby, the laser processing control device 2 controls the laser oscillator 1 and the laser processing unit 3.

Next, the configuration of the position correction amount calculation device 20 will be described. The position correction amount calculation device 20 according to the present embodiment selects a correction coefficient used for position shift correction based on the lens temperature and galvano coordinates.

FIG. 2 is a block diagram showing the configuration of the position correction amount calculation apparatus. The position correction amount calculation device 20 includes a pulse detection unit 21, a pulse storage unit 22, an integration unit 23, a correction coefficient storage unit 24, a correction amount calculation unit 25, an irradiation position input unit 26, a temperature input unit 27, and an output unit 28. ing.

The pulse detector 21 detects the laser beam L emitted from the laser oscillator 1 to the laser processing unit 3. The pulse detection unit 21 stores the detected emission timing (time) of each laser beam L in the pulse storage unit 22.

The pulse storage unit 22 is a memory that stores the emission timing of each pulse. The pulse storage unit 22 stores the emission timing of each pulse for a predetermined time (for example, 60 seconds), for example. Then, the pulse storage unit 22 deletes the stored emission timing when a predetermined time has elapsed. For example, the pulse storage unit 22 deletes the old emission timing by overwriting the new emission timing in the storage area of the emission timing that has become old after a predetermined time.

The integrating unit 23 calculates the integrated energy amount of the laser light L emitted from the laser oscillator 1 to the laser processing unit 3 during a predetermined time (for example, from 30 seconds before to the present time). For example, the integration unit 23 calculates the energy integration amount by multiplying the number of pulses of the laser light L emitted from the laser oscillator 1 during a predetermined time and the energy amount per pulse. The integration unit 23 calculates the energy integration amount on the assumption that the energy amount per pulse is a constant value.

The correction coefficient storage unit 24 is a memory that stores correction coefficients. The correction coefficient storage unit 24 stores a correction coefficient for each combination of lens temperature and galvano coordinates. The irradiation position input unit 26 extracts galvano coordinates from the machining program and sends them to the correction amount calculation unit 25. The irradiation position input unit 26 extracts galvano coordinates from an irradiation position command (information indicating the position where the laser beam L is irradiated) sent from the laser processing control device 2 to the laser processing unit 3, and calculates a correction amount calculation unit 25. May be sent to The temperature input unit 27 inputs the lens temperature detected by the temperature detection unit 38 and sends the lens temperature to the correction amount calculation unit 25.

The correction amount calculation unit 25 extracts a correction coefficient corresponding to the lens temperature and the galvano coordinates from the correction coefficient storage unit 24. The correction amount calculation unit 25 calculates the positional deviation correction amount using the energy integration amount calculated by the integration unit 23 and the correction coefficient extracted from the correction coefficient storage unit 24. The correction amount calculation unit 25 sends the calculated positional deviation correction amount to the output unit 28. The output unit 28 sends the positional deviation correction amount to the control unit 30.

Next, a processing procedure of laser processing by the laser processing apparatus 100 will be described. FIG. 3 is a flowchart showing a processing procedure of the laser processing according to the embodiment. When the laser processing device 100 starts laser processing, the laser processing control device 2 controls the laser oscillator 1 and the laser processing unit 3 in accordance with the processing program. Thereby, the emission of the laser beam L is started (step S10). Laser light L is emitted from the laser oscillator 1 at a timing according to the machining program. In the laser processing unit 3, the galvano mechanism, the XY table 32, and the like operate so that the laser light L is irradiated to a position according to the processing program. The temperature detector 38 detects the lens temperature.

The pulse detection unit 21 detects the laser beam L emitted from the laser oscillator 1 to the laser processing unit 3 and stores the detected emission timing of each laser beam L in the pulse storage unit 22 (step S20).

The irradiation position input unit 26 extracts the galvano coordinates from the machining program and sends them to the correction amount calculation unit 25. Further, the temperature input unit 27 sends the lens temperature detected by the temperature detection unit 38 to the correction amount calculation unit 25.

The integrating unit 23 calculates an energy integrated amount of the laser light L emitted from the laser oscillator 1 to the laser processing unit 3 during a predetermined time (for example, a time Tx described later) (step S30). The correction amount calculation unit 25 extracts a correction coefficient corresponding to the lens temperature and galvano coordinates from the correction coefficient storage unit 24 (step S40). The correction amount calculation unit 25 calculates the positional deviation correction amount by multiplying the energy integration amount calculated by the integration unit 23 and the correction coefficient extracted from the correction coefficient storage unit 24 (step S50). The correction amount calculation unit 25 sends the positional deviation correction amount to the output unit 28.

The output unit 28 sends the positional deviation correction amount to the control unit 30. Accordingly, the control unit 30 controls the

galvano scanners

36X and 36Y so as to correct the positional deviation of the laser light irradiation position using the positional deviation correction amount (step S60). In the laser processing unit 3, the

galvano scanners

36X and 36Y rotate the galvanometer mirrors 35X and 35Y so that the irradiation position of the laser beam L is corrected by the positional deviation correction amount.

FIG. 4 is a diagram for explaining the control of the galvano mechanism by the position correction amount calculation device. The position correction amount calculation device 20 detects the laser light L emitted from the laser oscillator 1. The lens temperature detected by the temperature detection unit 38 is input to the position correction amount calculation device 20.

The position correction amount calculation device 20 calculates a position shift correction amount based on the integrated amount of energy of the laser light L emitted from the laser oscillator 1 from a predetermined time before the current time, the lens temperature, and the galvano coordinates. To do. Then, the position correction amount calculation device 20 corrects the control of the galvano mirrors 35X and 35Y by the

galvano scanners

36X and 36Y based on the position shift correction amount.

Here, the relationship between the rising temperature of the fθ lens 34 and the amount of positional deviation from the target position of the laser light irradiation position will be described. FIG. 5 is a diagram illustrating the relationship between the rising temperature of the fθ lens and the amount of displacement. In FIG. 5, the horizontal axis is the rising temperature of the fθ lens 34, and the vertical axis is the amount of positional deviation from the target position of the laser light irradiation position. A characteristic 51 in FIG. 5 is an actual measurement value, and a characteristic 52 is a simulation value.

As the temperature of the fθ lens 34 rises, the amount of positional deviation from the target position of the laser light irradiation position increases. Since the

galvano scanners

36X and 36Y have dynamic characteristics, even if the rising temperature is 0 ° C., the positional deviation amount does not become zero as indicated by the characteristic 51. In this embodiment, the positional deviation correction of the laser light irradiation position is performed so that the positional deviation amount becomes zero.

The positional deviation amount of the laser light irradiation position differs depending on which position on the fθ lens 34 the laser light L is irradiated on the substrate 4 (galvano coordinates). For this reason, in this embodiment, a misalignment correction amount is set according to the passing position of the laser light L on the fθ lens 34. In other words, a correction coefficient corresponding to the galvano coordinates is selected, and the misalignment correction amount is calculated using the selected correction coefficient.

FIG. 6 is a diagram showing the relationship between the passing position of the laser beam on the fθ lens and the positional deviation correction amount. In FIG. 6, the horizontal axis is the distance from the center of the fθ lens 34 (hereinafter referred to as the lens center) (the position through which the laser light L passes), and the vertical axis is the positional deviation correction amount. FIG. 6 shows the amount of misalignment correction when the temperature of the fθ lens 34 increases by 1 ° C.

The laser light L scanned by the fθ lens 34 and the

galvano scanners

36X and 36Y is displaced in the direction of expansion and contraction with respect to the center of the lens due to the temperature rise of the fθ lens 34. When the laser light L passes through the center of the lens and is irradiated onto the substrate 4, the positional deviation amount is substantially zero, and the positional deviation correction amount is also substantially zero. As the distance from the lens center increases, the amount of misalignment increases and the amount of misalignment correction also increases.

As described above, since the amount of misalignment increases toward the end of the fθ lens 34, the amount of misalignment correction is set larger as the end of the fθ lens 34. In other words, the correction coefficient is corrected so that the positional deviation correction amount increases toward the end of the fθ lens 34. As a result, the smaller the laser beam L that irradiates the substrate 4 through the vicinity of the center of the fθ lens 34, the smaller the displacement correction is performed, and the laser beam L that irradiates the substrate 4 through the vicinity of the outer periphery of the fθ lens 34. Larger misalignment correction is performed. For example, as shown in FIG. 6, the misalignment correction amount is changed according to a linear function. As a result, the relationship between the distance from the lens center and the positional deviation correction amount is approximated by the first order, and the irradiation position of the laser light L is corrected.

In the position correction amount calculation device 20, the correction amount calculation unit 25 calculates the passing position (the distance from the lens center) of the laser light L on the fθ lens 34 based on the galvano coordinates. Then, the correction amount calculation unit 25 extracts a correction coefficient corresponding to the passing position of the laser light L on the fθ lens 34 from the correction coefficient storage unit 24. Thereby, the correction amount calculation unit 25 calculates the misalignment correction amount using the correction coefficient corresponding to the galvano coordinates.

Note that the correction according to the linear function is an example, and the correction may be performed using another method (such as a complex approximate expression of a quadratic function or more). For example, the correction method is set according to the structure of the fθ lens 34 and other structures (optical characteristics) in the laser processing apparatus 100.

FIG. 7 is a diagram for explaining misalignment and misalignment correction. FIG. 7 shows galvano area states 40A to 40C in which the positional deviation correction is performed. Each state 40A to 40C shows the relationship between the target irradiation position 41 of the laser beam L and the laser beam irradiation position 42.

State 40A is a state of the galvano area immediately after the start of laser processing. In addition, the state 40B is a state of the galvano area when the positional accuracy is deteriorated with the temperature increase of the fθ lens 34 (before the positional deviation correction). Further, the state 40C is a state of the galvano area after the positional deviation correction is performed when the temperature of the fθ lens 34 rises.

As shown in state 40A, immediately after the start of laser processing, there is no displacement between the target irradiation position 41 of the laser beam L and the laser beam irradiation position 42. Further, as shown in the state 40B, when the temperature of the fθ lens 34 increases, a positional deviation occurs between the target irradiation position 41 of the laser light L and the laser light irradiation position 42. Further, as shown in the state 40C, by performing the positional deviation correction, the positional deviation between the target irradiation position 41 of the laser light L and the laser light irradiation position 42 is eliminated.

FIG. 8 is a diagram showing the relationship between the actual temperature change of the fθ lens and the temperature detected by the temperature detector. In FIG. 8, the horizontal axis represents time (elapsed time from laser processing), and the vertical axis represents the temperature of the fθ lens 34. A characteristic 45 shown in FIG. 8 is an actual temperature change of the fθ lens 34, and a characteristic 46 is a temperature change detected by the temperature detection unit 38.

Before the laser processing is started, the temperature of the fθ lens 34 is a constant value (temperature t1). When laser processing is started at a predetermined pulse period after the elapse of time T1, the actual temperature of the fθ lens 34 gradually increases as indicated by the characteristic 45, and the temperature of the fθ lens 34 is a constant value after the elapse of the predetermined time. (Temperature t2). This is because the temperature of the fθ lens 34 rises when the laser light L passes through the fθ lens 34, but the temperature of the fθ lens 34 returns to the original temperature when a predetermined time elapses. In other words, the temperature of the fθ lens 34 is raised only for a predetermined time after the laser light L passes through the fθ lens 34. For this reason, when the irradiation of the laser beam L is stopped after the irradiation of the laser beam L, the temperature of the fθ lens 34 returns to the original temperature after the elapse of a predetermined time after the irradiation of the laser beam L is stopped. In the characteristic 45 shown in FIG. 8, since the irradiation with the laser light L is continued, the fθ lens 34 maintains the temperature t2 after rising to the temperature t2.

Since the temperature detection unit 38 is disposed at the end of the fθ lens 34, it takes time until the temperature detection unit 38 detects the temperature increase of the fθ lens 34 after the temperature of the fθ lens 34 actually increases. Cost. For this reason, the actual temperature change (characteristic 45) of the fθ lens 34 and the temperature change (characteristic 46) detected by the temperature detection unit 38 are different. Specifically, as shown in the characteristic 46, the detected temperature of the fθ lens 34 gradually increases after a lapse of a time T2 after the time T1, and the temperature of the fθ lens 34 is a constant value (after a predetermined time elapses). Temperature t2). For this reason, the temperature detection unit 38 detects that the fθ lens 34 has reached the temperature t2 after the actual temperature of the fθ lens 34 has reached the temperature t2.

For this reason, in the present embodiment, the misalignment correction amount is calculated based on the integrated energy amount of the laser light L. Then, a correction coefficient corresponding to the detected temperature of the fθ lens 34 is selected as necessary. For this reason, it is possible to calculate an accurate misregistration correction amount. The correction amount calculation unit 25 may select a correction coefficient corresponding to the energy integration amount.

Next, a method for calculating the integrated energy amount will be described. FIG. 9 is a diagram for explaining a method of calculating the energy integration amount. In FIG. 9, the laser pulse Px indicates the x-th pulse (x is a natural number).

The integration unit 23 of the position correction amount calculation device 20 calculates the integrated amount of laser pulse energy during the time (integration section) Tx. In other words, the integration unit 23 calculates a moving average of the energy integration amount. For example, when the nth pulse (n is a natural number) of laser pulses Pn is irradiated, the energy amounts of the 1st to nth laser pulses P1 to Pn during the time Tx are integrated to calculate the integrated energy amount. The

Thereafter, when the laser processing is continued, the energy amount of the laser pulse after the time Tx is subtracted from the integrated energy amount, and when a new laser pulse is emitted during the time Tx, a new laser pulse is generated. Is added to the integrated energy amount.

FIG. 9 shows a case where there is no laser pulse that has passed the time Tx when the (n + 1) th pulse of the laser pulse P (n + 1) is emitted. For this reason, there is no energy amount subtracted from energy integration amount. On the other hand, since the (n + 1) th laser pulse Pn is emitted during the new time Tx, the energy amount of the (n + 1) th pulse is added to the integrated energy amount. As a result, the integrated energy amount when the (n + 1) th pulse of the laser pulse P (n + 1) is emitted is a value obtained by summing the energy amounts from the laser pulses P1 to P (n + 1).

In FIG. 9, when the (n + 2) th laser pulse P (n + 2) is emitted, the laser pulses that have passed the time Tx are laser pulses P1 to P (n-2). Therefore, when the laser pulse P (n + 2) of the (n + 2) th pulse is emitted, the energy amount of the laser pulses P1 to P (n-2) is subtracted from the integrated energy amount as the laser pulse after the time Tx. The On the other hand, since the (n + 2) th laser pulse P (n + 2) is emitted during the new time Tx, the energy amount of the (n + 2) th pulse is added to the integrated energy amount. As a result, the integrated energy amount when the (n + 2) -th laser pulse P (n + 2) is emitted is the sum of the energy amounts from the laser pulses P (n−1) to P (n + 2). .

Note that the time Tx, which is the integration interval, varies depending on the structure around the fθ lens 34 and the environment (heat dissipation state). Therefore, the integration interval is optimized according to the actual structure and environment around the fθ lens 34.

In the present embodiment, the energy integration amount is calculated on the assumption that all the laser pulses within the time Tx have the same energy amount. However, the energy amount used for integration according to the time zone within the time Tx. May be changed. In other words, the energy amount may be weighted at each laser pulse emission time.

For example, a laser pulse irradiated in an old time zone within the time Tx (having a long elapsed time from pulse irradiation) has a small effect on the temperature rise of the fθ lens 34. On the other hand, a laser pulse irradiated in a new time zone within the time Tx (with a short elapsed time from pulse irradiation) has a large effect on the temperature rise of the fθ lens 34. For this reason, the amount of energy corresponding to the elapsed time from the pulse irradiation may be set for the laser pulse irradiated within the time Tx. In this case, a larger energy amount is set for a laser pulse having a shorter elapsed time from pulse irradiation, and a smaller energy amount is set for a laser pulse having a longer elapsed time from pulse irradiation. Then, “0” is set as the energy amount in the laser pulse that has passed the time Tx from the pulse irradiation. As a result, it is possible to calculate an accurate displacement correction amount corresponding to the temperature gradient of the fθ lens 34.

Next, an example of laser processing will be described. When performing laser processing, for example, laser light irradiation and a predetermined waiting state are repeated. FIG. 10 is a diagram for explaining a change in misalignment amount when the waiting time is set short, and FIG. 11 is a diagram for explaining a change in misalignment amount when the waiting time is set long. is there.

In FIGS. 10 and 11, the temporal change in the positional deviation amounts 61 and 62 and the fθ lens calculated temperature (simulation value) 60 when the laser processing is performed at a constant speed of 2000 Hz with the energy per pulse being 10 mJ. Is shown. The horizontal axis in FIGS. 10 and 11 is time, the left side of the vertical axis is the amount of displacement, and the right side of the vertical axis is the fθ lens calculated temperature. Further, the positional deviation amount when there is no positional deviation correction is the positional deviation amount 61, and the positional deviation amount when there is positional deviation correction is the positional deviation amount 62. Note that the integration interval (time Tx) of the energy integration amount was 30 seconds.

FIG. 10 shows misregistration amounts 61 and 62 and fθ lens calculated temperature 60 when laser light irradiation (processing) for 5 seconds and a waiting state for 15 seconds are repeated four times, and FIG. 11 shows a laser for 5 seconds. The positional deviation amounts 61 and 62 and the fθ lens calculated temperature 60 when the light irradiation and the waiting state for 30 seconds are repeated four times are shown.

As shown in FIG. 10, when laser light irradiation (processing of 10,000 holes) is performed for 5 seconds at a constant speed of 2000 Hz, the fθ lens calculated temperature 60 and the positional deviation amount 61 increase with the laser light L irradiation. During the waiting time (15 seconds), the fθ lens calculated temperature 60 and the positional deviation amount 61 are reduced by a predetermined amount, but do not return to the initial values. For this reason, when the first processing to the fourth processing are performed, the fθ lens calculated temperature 60 and the positional deviation amount 61 after each processing gradually increase.

On the other hand, in the present embodiment, even when laser light irradiation is performed at a constant speed of 2000 Hz for 5 seconds, the positional deviation correction is performed by an amount corresponding to the fθ lens calculated temperature 60. The value remains stable. And even if it is a case where 1st process to 4th process is performed, the positional offset amount 62 is stabilized with the low value.

As described above, it is understood that when the position deviation correction is not performed with respect to the temperature rise of the fθ lens 34 (positional accuracy correction is disabled), the position deviation amount increases with the temperature rise of the fθ lens 34. On the other hand, when the positional deviation correction is performed with respect to the temperature rise of the fθ lens 34 (positional accuracy correction is enabled), the positional deviation amount is constant (not increased) even if the temperature of the fθ lens 34 rises. I understand that.

As shown in FIG. 11, when laser light irradiation (processing of 10,000 holes) is performed for 5 seconds at a constant speed of 2000 Hz, the fθ lens calculation temperature 60 and the positional deviation amount 61 increase with the laser light L irradiation. Then, after the waiting time (30 seconds) elapses, the fθ lens calculated temperature 60 and the positional deviation amount 61 return to substantially initial values. For this reason, when the first processing to the fourth processing are performed, the fθ lens calculated temperature and the positional deviation amount 61 after each processing reach a predetermined size, and after 30 seconds as a waiting time, The fθ lens calculated temperature 60 and the positional deviation 61 return to substantially initial values. Even in this case, the amount of displacement increases during each processing.

As described above, when the positional deviation correction is performed on the fθ lens calculated temperature 60, it is understood that the positional deviation amount is constant (not increased) even if the temperature of the fθ lens 34 is increased. Since the integration interval is 30 seconds, the fθ lens calculated temperature 60 returns to the steady temperature with a waiting time of 30 seconds.

Here, the case where a waiting time is provided between laser processings has been described, but laser processing is continuously performed without providing a waiting time between laser processings. Also good.

Incidentally, the base temperature of the fθ lens 34 changes depending on the installation environment of the laser processing apparatus 100, the operating status of the laser processing apparatus 100, and the like. For this reason, when the base temperature changes to a predetermined value, the positional deviation may be corrected once by the

galvano scanners

36X and 36Y at the base temperature. As a result, the misalignment amount is once reset. In this case, it is not necessary to change the correction coefficient according to the base temperature (lens temperature).

It should be noted that a positional deviation correction amount at each laser light irradiation position may be calculated in advance. In this case, the integrating unit 23 calculates an energy integration amount for irradiating the laser beam irradiation position with the laser beam L with respect to each laser beam irradiation position in advance based on the machining program. Then, the correction amount calculation unit 25 calculates a positional deviation correction amount for each laser light irradiation position. The output unit 28 stores the calculated misregistration correction amounts in a storage unit (not shown) in the laser processing control device 2 or the like. When laser processing is started, the control unit 30 reads out the stored misregistration correction amount and performs misregistration correction using the misregistration correction amount for each laser light irradiation position.

As described above, according to the embodiment, the integrated energy amount corresponding to the temperature of the fθ lens 34 is instantaneously calculated. For this reason, it is possible to accurately correct the misalignment of the irradiation position (processing position) of the laser light L based on the integrated energy amount without causing a time difference. Therefore, it is possible to perform laser processing with good position accuracy.

As described above, the laser processing control device and the laser processing control method according to the present invention are suitable for drilling a substrate to be processed.

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Laser processing control apparatus 3 Laser processing part 4 Board | substrate 20 Position correction amount calculation apparatus 21 Pulse detection part 23 Accumulation part 24 Correction coefficient memory | storage part 25 Correction amount calculation part 30 Control part 34 f (theta)

lens

36X, 36Y Galvano scanner 38 Temperature Detection unit 100 Laser processing device L Laser light P1 to P (n + 2) Laser pulse

Claims

A pulse detector for detecting the emission timing of the pulse laser emitted from the laser oscillator to the substrate to be processed;
An integration unit that integrates each energy amount of the pulse laser emitted within a predetermined time to calculate an energy integration amount;
A correction amount for calculating a misalignment correction amount according to the integrated energy amount as a correction amount for correcting the irradiation position of the pulse laser to a desired position when a misalignment occurs in the pulse laser irradiated to the substrate to be processed A calculation unit;
A control unit that controls the processing unit that processes the substrate to be processed using the pulse laser so as to correct the irradiation position of the pulse laser based on the misalignment correction amount;
A laser processing control device comprising:
2. The laser processing control according to claim 1, wherein the correction amount calculation unit calculates a displacement correction amount according to a coordinate position in a galvano area of a pulse laser irradiated to the substrate to be processed. apparatus.
The correction amount calculation unit calculates a displacement correction amount according to a base temperature of an fθ lens through which the pulse laser transmitted from the laser oscillator to the substrate to be processed passes. The laser processing control apparatus described.
4. The integration unit according to claim 1, wherein the integration unit calculates the energy integration amount by integrating each energy amount according to an elapsed time after the pulse laser is emitted. The laser processing control apparatus described.
4. The laser processing control apparatus according to claim 1, wherein the integration unit calculates the energy integration amount with each energy amount of the pulse laser as a constant value.
6. The laser processing control apparatus according to claim 1, wherein the control unit corrects an irradiation position of the pulse laser by controlling a galvano scanner provided in the processing unit.
An emission step in which a laser oscillator emits a pulse laser toward the substrate to be processed;
A pulse detection step of detecting the emission timing of the pulse laser;
An integration step of calculating an energy integrated amount by integrating the energy amounts of the pulse laser emitted within a predetermined time;
A correction amount for calculating a misalignment correction amount according to the integrated energy amount as a correction amount for correcting the irradiation position of the pulse laser to a desired position when a misalignment occurs in the pulse laser irradiated to the substrate to be processed A calculation step;
A control step for controlling a processing unit that processes the substrate to be processed using the pulse laser so as to correct the irradiation position of the pulse laser based on the positional deviation correction amount;
A laser processing control method comprising: