JPH11192570A - Device and method of laser beam machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining device and its method that bring high yield and that realize high quality drilling. SOLUTION: This invention relates to a laser beam machining device and a method applicable to such device which is provided with a reflected light detector 12, a semiconductor device for detecting the intensity of light emitted by a laser generator 1 and reflected by a workpiece 7, with a control means 15 and the like for controlling the laser generator 1 based on a comparison between the intensity of the reflected light detected by the detector 12 and a prescribed reference value, and with a correcting means for correcting such intensity of the reflected light in accordance with the temperature change of the semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and a laser processing method, and more particularly, to a laser drilling apparatus and laser suitable for drilling a circuit board formed by laminating an insulating layer and a conductive layer. It relates to a processing method.

[0002]

2. Description of the Related Art In general, there is a so-called multilayer circuit board formed by alternately laminating insulating layers and conductive layers on a circuit board. Such a multilayer circuit board has a high mounting density. And is becoming widely used.

More specifically, in a multilayer circuit board, conduction between adjacent conductive layers is obtained by making a hole in an insulating layer and filling the hole with a solder, a conductive paste, or the like.

[0004] As a processing technique for forming a hole in an insulating layer, a technique utilizing laser light has been widely used.

The wavelength of the laser beam used is
For the insulating layer, a wavelength that is easily absorbed and a wavelength that is easily reflected for the conductive layer is used.For example, when the insulating layer is a glass epoxy resin and the conductive layer is a copper foil, a carbon dioxide gas laser beam is used. With the use, only the insulating layer can be selectively removed.

Here, it is needless to say that a hole is formed so that conduction between adjacent conductive layers can be surely obtained.

As such a conventional example, see, for example,
-92482.

According to this, when a workpiece is irradiated with laser light and a hole is drilled, direct transmitted light from a laser oscillator and reflected light from the workpiece are detected by separate sensors, respectively. The reflected light amount ratio is calculated from the amount of light, and the control of the laser light is performed by comparison with the reference value.

More specifically, the oscillator is stopped when the reflected light amount ratio becomes larger than a preset reference value.

By performing such an operation, the conductive layer can be prevented from being damaged by the laser beam, and at the same time, the processing time is shortened.

[0011]

However, the above-mentioned prior art has the following problems.

First, a semiconductor element and a photomultiplier tube can be cited as sensors for detecting infrared laser light typified by a carbon dioxide laser at high speed. In a typical semiconductor element sensor, the element is cooled with liquid nitrogen or the like. Otherwise, sufficient detection will not be possible.

Also, the photomultiplier tube has problems in that the device becomes large-scale and that handling of the device is inconvenient.

A sensor that can detect infrared laser light at high speed, is easy to handle, and has a compact device is a semiconductor device that can be operated at room temperature. However, a problem also occurs in this case.

The light detection semiconductor element increases the electrical conductivity or generates an electromotive force due to the energy of the light when the light is incident, and detects the amount of the incident light from the amount of change in the conductivity or the amount of the generated electromotive force. It works.

However, the change in conductivity and the change in electromotive force are:
This is explained by the fact that the generation amount of electron-hole pairs also changes according to the change in the amount of incident light. Therefore, the temperature of the semiconductor element itself greatly affects the detection sensitivity.

That is, when a semiconductor element for infrared detection is used at room temperature, the detection sensitivity changes according to the temperature change, so that accurate light intensity detection becomes impossible.

Therefore, in a laser processing apparatus that controls a laser oscillator and an optical system based on a comparison between the detected reflected light intensity and a reference value, such inaccurate detection of the laser light intensity is incomplete. This leads to hole processing and damage to the conductive layer, which causes a reduction in processing yield.

Various methods can be considered as a method of detecting a temperature change of a semiconductor element. However, the introduction of a detector only for temperature measurement, such as a thermocouple or a resistance change detection type thermometer, requires complicated equipment. This is not preferable because it leads to an increase in size and size.

Further, the number of times the temperature change is detected is that, when a laser beam is incident on the semiconductor element, the temperature of the semiconductor element always changes every moment regardless of the amount of the laser light. Even if the temperature is as small as possible, there is a case where the temperature detection performed only once immediately before the start of laser beam incidence is insufficient.

The signal output from the semiconductor element for photodetection is usually very weak and is amplified by an amplifier. However, if there is an individual difference between the semiconductor elements, the magnitude of the output signal from the amplifier cannot be used. The size will vary depending on the semiconductor element used.

Further, since the amplifier has a certain finite dynamic range, an overrange may occur due to a difference between semiconductor elements.

That is, it is necessary to control the magnitude of the signal input to the amplifier in order to eliminate the variation of the output signal due to the individual difference of the semiconductor element.

In the prior art, the transmitted light directly from the laser oscillator and the reflected light from the object to be processed are detected by separate sensors, and the reflected light amount ratio is calculated from the light amounts of the two to obtain a reference value. The control of the laser beam is performed in comparison with the above.

However, although the variation of the laser beam to be processed is corrected by calculating the reflected light amount ratio, for example, a hole of a conformal mask shape which is formed in advance only in the conductive layer on the substrate surface is processed. In this case, the amount of light reflected by the conformal mask may differ depending on the relationship between the irradiation position of the laser beam and the hole position.

Since the spatial intensity distribution of the laser beam is not uniform, it depends on the degree of overlap between the laser beam and the hole, so that the laser beam enters the conformal mask, that is, the amount of laser beam used for processing the insulating layer. This is because a difference occurs.

That is, when attention is paid to two holes to be processed in which the relationship between the irradiation position of the laser beam and the hole position is different, the reflected light amount ratio from the conformal mask included in the reflected light amount ratio is different from each other. Even if the ratio of the amounts of reflected light from the two holes is the same value, the processing states of the two holes are different from each other, which means that the reflected light is not correctly detected.

As described above, even if the control of the laser beam is performed based on the comparison between the ratio of the amount of reflected light different for each hole and a certain reference value, incomplete hole processing and damage to the conductive layer are led, and the processing yield is increased. Cause a decrease in

In view of the above points, the present invention corrects the intensity of a laser beam output from a laser beam detector using a semiconductor device in accordance with a temperature change of the semiconductor device detected at an appropriate timing. In some cases, by detecting not only reflected light intensity but also incident light intensity to obtain accurate light intensity, and controlling the laser oscillator based on comparison with a reference value,
An object of the present invention is to provide a laser processing apparatus and a laser processing method that realize high-yield drilling with high yield.

[0030]

In order to solve the above-mentioned problems, the present invention relates to a reflected light detector which is a semiconductor element for detecting the intensity of reflected light emitted from a laser oscillator and reflected by an object to be processed. Control means for controlling the laser oscillator based on a comparison between the intensity of the reflected light detected by the reflected light detector and a predetermined reference value; and a method of controlling the intensity of the reflected light detected by the reflected light detector to change in temperature of the semiconductor element. A laser processing apparatus having correction means for correcting according to the following, or further having an incident light detector on which laser light emitted from a laser oscillator is incident, wherein the control means detects the incident light detected by the incident light detector. The laser based on a comparison between a relative reference light intensity and a predetermined reference value corresponding to the intensity of the reflected light from the processing portion of the processing object, obtained by calculating from the intensity and the reflected light intensity detected by the reflected light detector. Control the oscillator Typified by the laser processing apparatus.

With such a configuration, in particular, by accurately detecting the state of the hole drilling of the object to be processed, and by controlling the laser oscillator thereafter, ideal hole drilling is performed, and as a result, conduction between adjacent conductive layers is achieved. To provide a laser processing apparatus capable of performing a hole processing such that a hole can be reliably obtained.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention first provides a laser oscillator for emitting a laser beam, an optical system for transmitting the laser beam to an object to be processed, and a laser beam from the object to be processed. A reflected light detector that detects the intensity of the reflected light, an optical system that propagates the reflected light to the reflected light detector, and a comparison between the reflected light intensity detected by the reflected light detector and a predetermined reference value. Control means for controlling a laser beam emitted from the laser oscillator based on the semiconductor device, wherein the reflected light detector is a semiconductor element, and further, the intensity of the reflected light detected by the reflected light detector is measured by the semiconductor element. This is a laser processing apparatus having a correction unit that corrects according to a temperature change.

With such a configuration, the influence of the temperature of the reflected light detector is eliminated, the state of, for example, drilling of the object to be processed is accurately detected, and the laser oscillator is controlled.
An ideal hole is formed, and as a result, a hole can be formed so that conduction between adjacent conductive layers is reliably obtained.

Here, the correcting means may correct the output signal of the reflected light detector according to a temperature change detected from a potential difference between both ends of the semiconductor element.
Simple, accurate and suitable. That is, it is possible to avoid the complexity and size of the device due to the introduction of the detector for the purpose of temperature measurement only.

According to a third aspect of the present invention, the laser oscillator is a pulsed laser oscillator. When n is an integer of 2 or more, the laser oscillator is used to correct the n-th signal detected by the reflected light detector. The time when the potential difference between both ends of the semiconductor element used is detected before the detection time of the n-th signal and after the detection time of the (n-1) -th signal is changed every moment by laser incidence. This is preferable because the temperature change of the semiconductor element that continues to be accurately grasped.

Alternatively, a laser oscillator for emitting laser light, an incident light detector for detecting the light intensity of the laser light, and an optical system for propagating the laser light to an object to be processed. A reflected light detector that detects the intensity of the reflected light from the processing object, an optical system that propagates the reflected light to the reflected light detector, an incident light intensity detected by the incident light detector, and the reflection. From the laser oscillator based on a comparison between the relative reflected light intensity and a predetermined reference value corresponding to the intensity of the reflected light from the processed part of the processing object, which is obtained by calculating from the reflected light intensity detected by the photodetector. It may be a laser processing apparatus having control means for controlling the emitted laser light.

With such a configuration, it is possible to accurately detect a processing state substantially based on reflected light from a processing portion of a processing target, for example, a hole processing portion, and to control a laser oscillator to make it ideal. Drilling can be performed, and as a result, drilling can be performed such that conduction between adjacent conductive layers is reliably obtained.

Also in this case, the reflected light detector and / or the incident light detector is a semiconductor device, and further, the reflected light detected by the reflected light detector and / or the incident light detector. And / or correcting means for correcting the intensity of the incident light according to the temperature change of the semiconductor element,
The influence of the temperature of the reflected light detector and the incident light detector can be eliminated, and as a configuration, the correcting means may be configured such that the correcting means includes a semiconductor of the reflected light detector and / or the incident light detector. Preferably, the output signal of the reflected light detector and / or the incident light detector is corrected according to a temperature change detected from a potential difference between both ends of the element.

The laser oscillator is a pulse laser oscillator, and when n is an integer of 2 or more, the reflected light and / or the incident light detected by the incident light detector are n.
The time when the potential difference between both ends of the semiconductor element used for correcting the nth signal is detected is before the detection time of the nth signal detected by the reflected light detector and / or the incident light detector, and ( The configuration after the detection time of the (n-1) th signal is preferable because the temperature change of the semiconductor element, which keeps changing every moment due to laser incidence, can be accurately grasped.

Here, as described in claim 8,
The laser oscillator is a pulsed laser oscillator, and the relative reflected light intensity is such that when n is an integer of 2 or more, the reflected light intensity and the incident light of each of the nth pulsed laser light and the previous pulsed laser light. Can be obtained using the strength of
The use of pulsed laser light is preferable because the processing state is accurately detected.

As described in the ninth aspect, the configuration may further include detector signal control means for controlling the magnitude of the output signal of the reflected light detector. As described, the detector signal control means has a power supply and a resistor arranged in series with the reflected light detector, and changes the voltage of the power supply and / or the resistance of the resistor to change the resistance of the reflected light detector. 2. A configuration for controlling the magnitude of an output signal,
As described in 1, the detector signal control means has a resistor arranged in parallel with the reflected light detector, and controls the magnitude of the output signal of the reflected light detector by changing the resistance value of the resistor. The configuration may be such that the variation of the magnitude of the output signal based on the individual difference of the semiconductor element is eliminated.

This configuration can be applied to an incident light detector, and further has a detector signal control means for controlling the magnitude of the output signal of the incident light detector. Specifically, the detector signal control means may include a power supply and a resistor arranged in series with the incident photodetector, and the voltage and / or the resistance of the power supply may be adjusted. A configuration in which the magnitude of the output signal of the incident light detector is controlled by changing the resistance value, or as described in claim 14, the detector signal control means includes a resistor arranged in parallel with the incident light detector. It may have a configuration in which the magnitude of the output signal of the incident light detector is controlled by changing the resistance value of the resistor, and similarly, the variation of the magnitude of the output signal based on the individual difference of the semiconductor element is reduced. To eliminate.

Next, according to the present invention, an irradiation step of irradiating a laser beam emitted from a laser oscillator onto a processing object and the intensity of light reflected from the processing object are measured by a semiconductor device. A reflected light detection step for detecting the intensity of the reflected light detected in the reflected light detection step, a correction step of correcting the intensity of the reflected light detected in the reflected light detection step according to a temperature change of the semiconductor element, and a correction step of correcting the intensity of the reflected light. A laser processing method for controlling a laser beam emitted from the laser oscillator based on a comparison between the intensity of the reflected light and a predetermined reference value.

With such a configuration, the influence of the temperature in the reflected light detection process is eliminated, the state of, for example, the hole drilling of the object to be processed is accurately detected, and the laser oscillator is controlled so that the ideal hole is formed. Processing can be performed, and as a result, hole processing can be performed such that conduction between adjacent conductive layers is reliably obtained.

In this case, in the correcting step, the output signal of the reflected light detector is corrected according to a correction operation formula according to a temperature change detected from a potential difference between both ends of the semiconductor element. Is simple, reliable and suitable.

Alternatively, an irradiation step of irradiating a laser beam emitted from a laser oscillator to a processing object, an incident light detection step of detecting an intensity of the laser light, A reflected light detection step of detecting the intensity of the reflected light from the semiconductor device using a semiconductor element, and calculating from the intensity of the incident light detected in the incident light detection step and the intensity of the reflected light detected in the reflected light detection step And a control step of controlling the laser light emitted from the laser oscillator based on a comparison between a relative reflected light intensity corresponding to the intensity of the reflected light from the processed portion of the processing target and a predetermined reference value. It is a laser processing method having.

With such a configuration, it is possible to accurately detect the processing state substantially based on the reflected light from the processing portion of the hole processing of the processing object, and to control the laser oscillator to obtain the ideal hole. Processing can be performed, and as a result, hole processing can be performed such that conduction between adjacent conductive layers is reliably obtained.

Here, specifically, in the irradiation step, a pulse laser beam is irradiated in the irradiation step, and the relative reflected light intensity used in the control step is calculated by the following equation (2). Is preferable in that a processing state substantially based on reflected light from a processing portion of a hole in a processing target is accurately detected.

[0049]

(Equation 2)

Here, c _n = k × (b _n / a _n ), c _max =
_{k × (b max / a max} ), k is an arbitrary constant, a _n is the information about the n-th incident laser beam intensity, b _n information about n-th reflected laser beam intensity, a _max relates the incident laser beam intensity The maximum value of the information, b _max is the maximum value of the information regarding the reflected laser beam intensity, and n is an integer of 2 or more.

Further, as the object to be processed, a multi-layer substrate on which an insulating layer and a conductive layer are laminated can be suitably used as the object to be processed.

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a laser processing apparatus according to the present embodiment. In FIG. 1, 1 is a pulse laser oscillator used as an example of a processing light source, 2 is a bend mirror, 3
Is a beam splitter, 4 is a first scanning mirror, 5 is a second scanning mirror.
A scanning mirror 6 is a condenser lens for processing, and constitutes an optical system in an optical path.

Here, as the pulse laser oscillator 1 used in the present embodiment, for example, a carbon dioxide laser oscillator excited by microwaves can be suitably used.

Next, reference numeral 7 denotes a multi-layer substrate which is an object to be processed. The multi-layer substrate includes an insulating layer 8 and a conductive layer 9, and a processing hole 10 can be formed. Reference numeral 11 denotes a moving mechanism for the multilayer substrate 7, on which the multilayer substrate 7 is placed.

Reference numeral 12 denotes a reflected light detector for detecting reflected light from the multilayer substrate 7, reference numeral 13 denotes an amplifier for amplifying a signal from the reflected light detector 12, and reference numeral 14 denotes an output signal from the reflected light detector 12. And a control device 15 for controlling the pulse laser oscillator 1, the first scanning mirror 4, and the second scanning mirror 5.

The reference numerals 100a to 100g denote the pulsed output laser light oscillated from the laser oscillator 1 and the optical system 2
6, the laser beam reflected by the multilayer substrate 7 as the object to be processed, transmitted through the beam splitter 3 through the optical systems 6 to 4, and incident on the reflected light detector 12, together with the optical path thereof. Is shown. Here, the laser light in the optical path toward the multilayer substrate 7 and the laser light in the optical path reflected by the multilayer substrate 7 and returning toward the laser oscillator 1 are opposite in direction between the beam splitter 3 and the multilayer substrate 7. Although the direction is the same, the optical path is the same light beam.

With the above configuration, the processing hole 10 is formed in the multilayer substrate 7. This operation will be described in more detail.

First, as shown by 100b and 100c, the output laser beam 100a emitted from the pulse laser oscillator 1 is reflected by the bend mirror 2 and the beam splitter 3, respectively, and then the first laser beam is constituted by a galvano mirror. The scanning mirror 4 and the second scanning mirror 5 also composed of a galvano mirror make 100 d and 1
Laser light indicated by 00e is sequentially reflected in a scannable manner corresponding to a required processing mode.

Here, in the case of the present embodiment, the first scanning mirror 4 and the second scanning mirror 5 are configured to scan laser beams in directions orthogonal to each other.
The laser beam is used to scan the multilayer substrate 7 two-dimensionally.

Then, the light is incident on the processing condenser lens 6 composed of the fθ lens, and while being condensed as indicated by 100f, placed on the moving mechanism 11 and incident on the multilayer substrate 7 at the processing position. Is done.

Then, processing is performed to form a processing hole 10 in the multilayer substrate 7 by using the condensed output laser light as described above.

Further, a part of the laser light irradiated on the multilayer substrate 7 in this way is reflected by the multilayer substrate 7 to become a reflected laser light.

This reflected laser light propagates in the opposite direction through the laser light path through which the incident laser light has passed, and
As indicated by reference numerals 0f to 100c, the light reaches the beam splitter 3 in the order of the condenser lens 6, the scanning mirrors 5, 4 and is transmitted through the beam splitter 3 to enter the reflected light detector 12 as indicated by 100g. Will be.

The detection signal relating to the light intensity of the laser light detected by the reflected light detector 12 is amplified by an amplifier 13 to an arbitrary constant multiple, and then sent out to an arithmetic processing unit 14 for arithmetic processing. That is, the arithmetic processing unit 14
Is output to the control device 15 and the control device 15
Controls the laser oscillator 1 and the scanning mirrors 4 and 5.

Next, a configuration for controlling the laser oscillator 1 and the scanning mirrors 4 and 5 based on a detection signal relating to the light intensity of the laser light detected by the reflected light detector 12 will be described.

FIG. 2 shows how the processing hole 10 gradually becomes deeper. FIG. 2 (a) shows that the processing hole has not yet reached the conductive layer 9, and FIG. 2 (b) shows one of the processing holes. FIG. 2C is a schematic diagram showing a state where the portion has reached the conductive layer 9, and FIG.

Here, since most of the reflection of the laser beam occurs in the insulating layer 9, the amount of the reflected laser beam is as shown in FIG.
(A), (b), and (c) increase in this order.

The signal relating to the light intensity of the laser beam detected by the reflected light detector 12 is sent to the arithmetic processing unit 14 via the amplifier 13 and is supplied to the reference value preset in the arithmetic processing unit 14. It is determined whether or not the processing is completed, and the information is sent to the control device 15.

For example, when the reference value is set to an intermediate value between the amount of reflected light from the state of the hole in FIG. 2B and the amount of reflected light from the state of the hole in FIG. Since the amount of reflected light from is smaller than the reference value, the arithmetic processing unit 14 determines that the processing has not been achieved, and sends a command signal to the control device 15 to irradiate the laser oscillator 1 with laser light.

On the other hand, since the amount of reflected light from the hole shown in FIG. 2C is larger than the reference value, the arithmetic processing unit 14 determines that the processing has been completed, and the control unit 15 notifies the control unit 15 of the position of the hole. A command signal for not performing the above laser irradiation is sent, and a command signal for stopping emission of laser light is sent to the laser oscillator 1. Here, of course, the laser light from the laser oscillator 1 may be kept emitted, and the laser light may not reach the multilayer substrate 7 in the subsequent optical system.

Through the above-described processes, in principle, a hole can be formed at a high yield so that conduction between adjacent conductive layers can be reliably obtained.

The determination as to whether or not sufficient drilling has been achieved in the above process is based on whether the signal relating to the light intensity of the reflected laser light is larger or smaller than a reference value.

However, when the reflected light detector 12 is a semiconductor, the fluctuation of the ambient temperature may affect the signal intensity related to the light intensity of the reflected laser light.

If the magnitude of the signal changes in accordance with the temperature change, a correct judgment cannot be made in comparison with the reference value.

That is, if a signal larger than the original signal is sent from the reflected light detector 12 to the arithmetic processing unit 14 via the amplifier 13 due to a change in temperature, the actual drilling has not been completed. Nevertheless, the arithmetic processing unit 14 determines that the processing has been completed, and sends a command signal to the control unit 15 not to perform further laser irradiation on the hole position. Therefore, it is impossible to obtain a hole that ensures the conduction of the hole.

On the other hand, a signal smaller than the original signal is transmitted from the reflected light detector 12 through the amplifier 13 to the arithmetic processing unit 1.
4, the arithmetic processing unit 14 determines that the drilling has not been completed even though the actual hole drilling has been completed, and issues a command signal for further irradiating the controller 15 with laser light. However, if laser irradiation is performed on a hole that has already been processed, a desired hole processing shape cannot be obtained, or the conductive layer 9 will be damaged.

FIG. 3 is a schematic diagram of a measuring system according to the present embodiment, and FIG. 4 is a graph showing a state of a change in a signal output from the amplifier 13 due to a temperature change by such a measuring system.

In FIG. 3, 1 is a pulse laser oscillator,
Reference numeral 13 denotes an amplifier, which is the same as that described with reference to FIG. Reference numeral 30 denotes a laser beam detector, 31 denotes a thermometer, and 32 denotes an oscilloscope.

Here, the laser light detector 30 corresponds to the reflected light detector 12 in FIG. 1, and as a semiconductor element for laser light detection, mercury cadmium telluride (HgCdTe) which is one of the mercury-based semiconductor elements operating at room temperature. ) A compound semiconductor element is used.

In such a configuration, the laser oscillator 1
Laser light 10 representatively showing the laser light emitted from
0h is incident on the laser light detector 30, and the laser light detector 30 outputs a voltage signal corresponding to the size of the incident laser light, and after being amplified by the amplifier 13 to an arbitrary constant times, The signal is transmitted to the oscilloscope 32.

In FIG. 4, the horizontal axis represents the temperature of the housing of the laser beam detector 30 measured by the thermometer 31, and the vertical axis represents a carbon dioxide laser beam having a peak of about 100 mW (wavelength 1).
0.6 μm) shows a peak height voltage confirmed on the oscilloscope 32 when a pulse is incident on the laser light detector 30.

As shown in FIG. 4, as the temperature rises by about 10 ° C., the peak height voltage decreases linearly by about 3 V from 7 V to 4 V.

In other words, although the peak height voltage decreases by 0.3 V due to the temperature rise of 1 ° C., it is considered that a temperature change of about 1 ° C. can easily occur. For example, the peak height voltage of 5 V (24 (Corresponding to the value at about ° C).
A decrease of 3 V corresponds to a 6% error.

As described above, when the temperature of the semiconductor element changes, the output signal also changes, and as a result, correct laser light detection is not performed, which adversely affects the processing yield and quality.

Therefore, in order to suppress the occurrence of an error due to a temperature change, it is necessary to correct the temperature of the output signal.

That is, if the reference value to be compared with the output signal is determined to be a value at an arbitrary temperature, for example, a value at 22 ° C., the reflected light detector The signal detected by 12 is corrected to a signal at 22 ° C. based on a correction operation expression (for example, an expression showing a straight line shown in FIG. 4) determined in advance, and the corrected signal is compared with a reference value. By doing so, highly accurate judgment can be made.

By the way, various methods can be considered as a method of detecting a temperature change of a semiconductor element. However, introduction of a detector for only temperature measurement, such as a thermocouple or a resistance change detection type thermometer, requires complicated equipment. This is not preferable because it leads to an increase in size and size.

Therefore, as a method of detecting a temperature change of a semiconductor element, it is particularly preferable to detect a temperature change from a change in the resistance value of the semiconductor element itself, specifically, a change in a potential difference between both ends of the semiconductor element.

The reason for this is that not only semiconductors but also conductive substances in general change in temperature as the vibration state of the molecules constituting them also changes, so that the resistance value also changes. This is because, since the potential difference between both ends of the semiconductor element also changes, it has been noted that by measuring this potential difference, a temperature change of the semiconductor element can be detected without using another temperature detector.

FIG. 5 is a schematic diagram of a measurement system for measuring a potential difference between both ends of the laser light detector 30, and FIG. 6 is a graph showing a state of a change in the potential E with a change in temperature.

As shown in FIG. 5, the potential difference between both ends of the laser light detector 30 composed of a semiconductor element is a potential e, and the voltage value of the potential e is amplified by the amplifier 13 to an arbitrary constant multiple and the potential is increased. E, and then transmitted to the oscilloscope 32.

At this time, no laser light is incident on the laser light detector 30. Here, the laser light detector 3
When the temperature of 0 changes, the resistance of the semiconductor element as the laser light detector also changes, and the potential e changes accordingly.

FIG. 6 is a graph showing this state. 6, the horizontal axis indicates the temperature of the housing of the laser light detector 30 measured by the thermometer 31, and the vertical axis indicates the potential E confirmed on the oscilloscope 32.

As shown in FIG. 6, as the temperature rises by about 10 ° C., the value of potential E also decreases linearly from 7 V to −4 V.

As described above, there is a certain relationship between the temperature of the semiconductor element and the potential E, and the temperature of the semiconductor element, that is, the temperature of the laser light detector 21 can be obtained by measuring the potential E. it can.

Thus, by measuring the potential E in this way, it is possible to avoid the complexity and size increase of the device due to the introduction of a detector such as a thermocouple or a thermometer for the purpose of temperature measurement only.
The temperature of the reflected light detector 12 in FIG. 1 can be obtained.

Further, the reflected laser light measured based on the temperature of the reflected light detector 12 obtained from the measurement of the potential E is corrected, and a signal related to the corrected light intensity is compared with a reference value. By doing so, it is possible to make an accurate pass / fail judgment of the hole processing, and it is possible not only to reliably perform the hole processing so that the conduction between the adjacent conductive layers can be reliably obtained, but also to waste the output laser light. Oscillation can be avoided and processing throughput can be increased.

As described above, according to the present embodiment, the temperature of the reflected light detector can be obtained by measuring the potential E, that is, by measuring the potential at both ends of the semiconductor element. While avoiding the complexity and size of the equipment by introducing detectors only for temperature measurement such as
The temperature of the output signal can be corrected, and the accuracy of the processing state can be determined with high accuracy.

In this embodiment, the signal is amplified by using the amplifier. However, the magnitude of the signal sent from the laser beam detector must be large enough when the arithmetic processing unit performs signal detection. If you have, an amplifier is not always required.

Further, in this embodiment, the laser oscillator is a pulse laser oscillator.
In some cases, a laser oscillator that emits laser light continuously can be used.

In this embodiment, a galvano mirror is used as a scanning mirror. However, a similar effect can be obtained by using a polygon mirror, an acousto-optic device, an electro-optic device, a hologram scanner, or the like.

Further, in the present embodiment, the fθ lens is used as the condensing lens for processing, but the same effect can be obtained by using an optical system in which a single lens or a plurality of Fresnel lenses are combined. .

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described in detail with reference to the drawings.

FIG. 7 is a schematic diagram of a laser processing apparatus according to the present embodiment. 7, the bend mirror 2 in the configuration of the first embodiment shown in FIG. 1 is replaced with a beam splitter 40, and an incident light detector 41 is provided so as to detect a part 100i of the output laser light transmitted through the beam splitter 40. A detection signal relating to the light intensity of the laser light detected by the photodetector 41 is amplified by an amplifier 42 to an arbitrary constant multiple, and then sent out to the arithmetic processing unit 14 for arithmetic processing. The configuration is the same as that of the first embodiment, except that the target multilayer substrate 43 includes a first conductive layer 44, an insulating layer 45, and a second conductive layer 46.

That is, in this embodiment, the basic function of detecting the reflected laser light and controlling the processing is the same as that of the first embodiment. It has a configuration that enhances the function of detection.

In the first embodiment described above, a signal relating to the light intensity of the reflected laser light is detected, and processing is controlled based on the result of comparison with the reference value.

However, in the first embodiment, the laser oscillator 1
Although it is basically assumed that the intensity of the output laser light 100a from has a temporally invariant intensity, or that the pulse laser has a temporally invariant profile, When the intensity of the output laser light varies with time or when the absolute intensity of the reflected laser light 100f from the multilayer substrate 7 is weak, for example, the time profile of the pulsed laser light intensity is a trigonometric function or a quadratic function, and It is considered that it is difficult to secure the detection accuracy, for example, when detecting the light intensity at the time of rising or falling of the pulse.

The first conductive layer 44 as shown in FIG.
When the multi-layer substrate 43 having the surface is processed, the reflected laser light 100f includes the reflected light from the first conductive layer 23 regardless of the state of the processed hole 17, and the laser light Depending on the relationship between the irradiation position and the hole position, even if the amount of reflected light from the two holes is the same value, the processing states of the two holes will be different from each other, and the state in which the reflected light detection is not performed correctly Can also occur.

In consideration of such a case, the above (Equation 2)
Calculating the relative reflected light intensity from the incident laser light intensity and the reflected laser light intensity by using the arithmetic expression shown in the above, and controlling the laser oscillator and the optical system based on a comparison between the obtained relative reflected light intensity and the reference value. Is preferred.

In the following, a specific description will be given with reference to figures. First, for the sake of simplicity, the value of the constant k described in (Equation 2) is set to a value that satisfies k × b _max = a _max .

As a result, c _max = 1, and (Equation 2)
Is represented as the following (Equation 3).

[0113]

(Equation 3)

First, consider the light reflected from a given hole A. When the hole A is continuously irradiated with the pulse laser light over time, the information about the peak value of the first pulse laser light is c ₁ = 0.1, and the information about the peak value of the N-th pulse laser light is c _N. = 0.7.

This means that in the first pulse laser beam, the laser beam reflected by the first conductive layer 44 is 0.1, and 0.9 is used for drilling holes. In the second pulse laser beam, 0.6 obtained by subtracting 0.1 from 0.7 means reflected light from the inside of the hole.

At this time, the Nth relative reflected light intensity is found to be 0.667 from (Equation 3).

Next, the reflected light from an arbitrary hole B will be discussed. When the hole B is continuously irradiated with the pulse laser light over time, the information about the peak value of the first pulse laser light is c ₁ = 0.3, and the information about the peak value of the N-th pulse laser light is c _N. = 0.7.

This means that the laser beam reflected by the first conductive layer 44 is 0.3, 0.7 means that the laser beam is used for drilling, and that the N-th pulse has a value of 0.7. 0.4 obtained by subtracting 0.3 means reflected light from the inside of the hole.

At this time, the N-th relative reflected light intensity is 0.571 from (Equation 3). However, neither of the holes A, since B also has information c _N about the peak value of the N-th pulse laser beam having the same value of 0.7, simply drilling only from the information about the peak value of the N-th pulse laser beam If you try to judge the suitability of this, you will lead to incorrect conclusions.

Therefore, it is examined by using the relative reflected light intensity based on (Equation 2) and (Equation 3) how much light amount ratio returns as reflected light with respect to the light amount actually irradiated inside the hole. By doing so, it is possible to make an accurate pass / fail judgment of the hole processing, and it is possible not only to reliably perform the hole processing so that the conduction between the adjacent conductive layers can be reliably obtained, but also to waste the output laser light. Oscillation can be avoided and processing throughput can be increased.

In this embodiment, the description has been made assuming the peak value of the pulsed laser light as the value of the information on the laser light intensity used in the arithmetic expression. It is needless to say that the same effect can be obtained by using the laser beam intensity after a certain time has elapsed from the rise or fall of the signal as a trigger.

For the sake of simplicity, the constant k is set to k × b
_The description has been made assuming that _max = a _max is satisfied. However, any value may be used as the constant k as long as it is a real number.

Furthermore, in order to obtain c _max in (Equation 2), it is preferable to use a method in which data on a gold mirror, a copper mirror, or the like is used instead of a processing object before actual processing. Alternatively, it may be obtained by using data acquired during actual processing as needed.

In the equations described in (Equation 2) and (Equation 3), c ₁ is a value obtained from the first incident laser light intensity and the first reflected light intensity. If the amount of light reflected from the bottom of the hole is almost zero, the first value may not be used.

[0125] Further, if the spatial variation when the incident laser beam intensity is in the state almost negligible, a _n is n
Can be considered almost constant regardless of the value of
Of course, a similar effect can be obtained by using an arithmetic expression represented by the following (Equation 4) instead of (Equation 2).

[0126]

(Equation 4)

Here, b _n is the information on the n-th reflected laser light intensity, and b _max is the maximum value of the information on the reflected laser light intensity. At this time, if it is known in advance a _n is almost constant regardless of the value of n, there is no need to set the incident light detector 41, as a matter of course.

Also, in the incident light detector of the present embodiment, it is of course possible to apply a configuration for correcting the temperature to the output signal of the reflected light detector of the first embodiment.

Embodiment 3 Hereinafter, Embodiment 3 of the present invention will be described in detail with reference to the drawings.

FIG. 8 is a schematic diagram showing the configuration near the reflected light detector 12 in more detail in the laser processing apparatus of the present embodiment.

In FIG. 8, reference numeral 12 denotes a reflected light detector;
Denotes an amplifier, and 14 denotes an arithmetic processing unit, which has the same configuration as that of the first embodiment. 100 g is a reflected laser beam transmitted through a beam splitter (not shown), 50 is a constant voltage source, and 51 is a series resistor.

With the above configuration, the reflected light detector 12
The reflected laser light 100g is detected, and a signal relating to the reflected laser light intensity is transmitted to the arithmetic processing unit 14 via the amplifier 13. This operation will be described in more detail.

First, when the reflected laser light 100g is incident on the reflected light detector 12, the resistance value of the reflected light detector 12 changes in proportion to the size of the reflected laser light.

Since the resistance value R of the series resistor 51 and the voltage value V of the constant voltage source 50 are constant, the potential e also changes in proportion to the amount of change in the resistance value of the reflected light detector 10.

The amount of change in the potential e is determined by the reflected light detector 12.
Is a signal to be output. The output signal from the reflected light detector 12 is amplified by the amplifier 13 by the gain of the amplifier and sent to the arithmetic processing unit 14.

By the way, the semiconductor elements constituting the reflected light detector 12 have individual differences in their photoelectric characteristics, and even when the same laser light is incident, the magnitude of the output signal is
It differs depending on each semiconductor element.

Since the dynamic range of the amplifier 13 has an upper limit, when the output signal is large, there is a possibility that the amplification cannot be completed and an overrange occurs.

In order to eliminate the variation of the output signal due to the individual difference of the semiconductor element, it is necessary to control the magnitude of the signal input to the amplifier 13.

FIG. 9 is a graph showing the relationship between the bias current of the reflected light detector 12 and the signal output from the amplifier 13.

In FIG. 9, the horizontal axis represents the bias current value applied to the reflected light detector 12, and the bias current value is represented by V, the voltage value of the constant voltage source 50, the resistance value R of the series resistor 51, and if the resistance value when the reflected light detector 12 the laser beam is not incident to r _d, the bias current value I
_b is determined by the following equation (5).

[0141]

(Equation 5)

The vertical axis indicates the magnitude of the signal output from the amplifier 13. At this time, the reflected light detector 1
It is assumed that the size of 100 g of the reflected laser light incident on 2 is constant.

As shown in FIG. 9, when the bias current value is doubled, the magnitude of the output signal is halved, and the relationship between the two is inversely proportional.

Since the gain of the amplifier 13 is constant, the fact that the output signal from the amplifier 13 shows such a change means that the magnitude of the output signal from the reflected light detector 12 has changed. ing.

[0145] That is, in order to control the magnitude of the output signal from the reflected light detector 12, becomes to the fact that it is sufficient to control the bias current I _b, from equation (5), the resistance of the series resistor 51 It can be seen that the magnitude of the output signal can be controlled by changing the value R, changing the voltage value V of the constant voltage source 50, and further changing the combination thereof.

As described above, according to the present embodiment, by changing the resistance value R of the series resistor 51 and / or the voltage value V of the constant voltage source 50, the magnitude of the output signal from the reflected light detector 12 is increased. The output of the amplifier 13 can be prevented from being over-ranged even if the reflected light detector has individual differences.

In this embodiment, the reflected light detector 12
However, it is needless to say that a similar effect can be obtained by applying such a configuration to the incident light detector 41 of the second embodiment.

The series resistor 51 may be a fixed resistor or a variable resistor, but a resistor having a small error with respect to temperature fluctuation, for example, a metal film resistor is preferably used.

Embodiment 4 Hereinafter, Embodiment 4 of the present invention will be described in detail with reference to the drawings.

FIG. 10 is a schematic diagram showing the configuration near the reflected light detector 12 in more detail in the laser processing apparatus of the present embodiment.

In FIG. 10, 12 is a reflected light detector, 1
Reference numeral 3 denotes an amplifier, and 14 denotes an arithmetic processing unit.
The configuration is the same as that described above. 100 g is a reflected laser beam transmitted through a beam splitter (not shown), 50 is a constant voltage source, 51 is a series resistor, 52 is a first parallel resistor, and 53 is a second parallel resistor.

The above configuration is the same as that of the third embodiment except that two parallel resistors 31 and 32 are added to the reflected light detector 10.

In the third embodiment, the semiconductor elements constituting the reflected light detector 12 have individual differences, and in some cases, the output from the amplifier 18 may be over-ranged. In the present embodiment, another configuration for controlling the magnitude of a signal input to the amplifier 13 by adding two parallel resistors 52 and 53 to the reflected light detector 12 will be described. .

In FIG. 10, if the resistance of the first parallel resistor 52 is r ₁ and the resistance of the second parallel resistor 53 is r ₂ , the signal output from the reflected light detector 12 is
By decreasing the signal according to the values of 2, 53 and inputting the reduced signal to the amplifier 13, it is possible to avoid an overrange of the output from the amplifier 13.

Here, the magnitude of the signal input to the amplifier 13 can be controlled by changing the resistance value r _{1 of} the first parallel resistor 52 and / or the resistance value r ₂ of the second parallel resistor 53. Where p is the output signal of the reflected light detector 12 and
Assuming that the magnitude of the signal input to P.3 is P, the relationship is represented by the following equation (6).

[0156]

(Equation 6)

As shown in (Equation 6), the magnitude of the signal input to the amplifier 13 can be controlled by changing the resistance values of the two parallel resistors 52 and 53. 13 can be avoided.

However, what should be noted here is the size of r ₁ and r ₂ . Because, since it is not desirable to change the bias current I _b of the reflected light detector 12, to avoid as much as possible the flow of current to the parallel circuit side, r _1, light reflecting the resistance value of r ₂ detector 12 It is preferable that the resistance value be as large as possible than the resistance value possessed by.

As described above, according to the present embodiment, it is possible to control the magnitude of the signal input to the amplifier 13 by changing the resistance values of the two parallel resistors 52 and 53. Even if there is an individual difference in the reflected light detector 12, the amplifier 1
3 can be avoided.

In this embodiment, the reflected light detector 12
However, it is needless to say that a similar effect can be obtained by using the configuration relating to the incident light detector.

The two parallel resistors 52 and 53 may be fixed resistors or variable resistors, but a resistor having a small error with respect to temperature fluctuation, for example, a metal film resistor is preferably used.

(Embodiment 5) Hereinafter, Embodiment 5 of the present invention will be described in detail with reference to the drawings.

FIG. 11 is a schematic diagram of the output signal waveform detected by the oscilloscope 32 in the measuring system shown in FIG. 3 of the first embodiment, and FIG. (B) shows the time change of the output from the amplifier 13 at an arbitrary time at least 0.1 second or more after the start of the incidence of the laser beam 100h.

The three signal waveforms shown in FIG. 11A are the laser pulse waveforms of the first, second, and third shots from the left, respectively, and the three signal waveforms shown in FIG. Are the N, N + 1, and N + 2 shots in the same manner.

As can be seen from FIG. 11A, immediately after the start of laser beam incidence, the overall potential gradually decreases with an increase in the incident laser pulse light.

This potential drop phenomenon continues until about 0.1 second after the start of laser beam irradiation, regardless of the pulse repetition frequency between 50 Hz and 1000 Hz, and thereafter, FIG. It was confirmed that no change in the potential was observed as shown in FIG.

For example, under the conditions of a repetition frequency of 100 Hz and a pulse width of about 100 microseconds, the potential dropped by about 0.4 V from the start of laser beam incidence to 0.1 second.

It can be seen from the graph of FIG. 6 that this potential drop of 0.4 V corresponds to a temperature rise of 0.36 ° C.
Laser light detector 30 which was simultaneously monitored by thermometer 31
No change was observed in the temperature of the housing.

This is because the temperature of the semiconductor element itself changes due to the incidence of the laser beam, but the laser irradiation time of 0.1 second is too short for heat generated in the semiconductor element to conduct to the case temperature measuring point. It is.

As described above, under such conditions, the temperature of the semiconductor element continues to change from immediately after the start of laser beam incidence until 0.1 seconds later, and reaches a thermal equilibrium state after 0.1 seconds. No change in the temperature of the semiconductor element due to the incidence of the laser beam is observed.

As shown in FIG. 4, when the temperature of the semiconductor element changes, the peak height voltage indicating the laser beam intensity also changes. Therefore, it is necessary to correct the output signal according to the temperature change. As described above.

Therefore, the number of times of detection of the potential difference between both ends of the semiconductor element is such that the temperature is detected for each signal to be corrected during the period from immediately after the start of laser beam incidence to 0.1 seconds later, ie, between the both ends of the semiconductor element. Performing the potential difference detection leads to highly accurate correction.

More specifically, in such a case, the timing of detecting the potential difference between both ends of the semiconductor element is as follows.
before the detection time of the pulse laser light of the n-th shot,
In addition, any time after the detection time of the pulse laser beam of the (n-1) -th shot may be used.

However, when the signal output is a laser pulse that attenuates exponentially, the time at which the influence of the (n-1) th shot is minimized, that is, the irradiation of the nth shot starts. Immediately before the time is a time suitable for detecting the potential difference.

On the other hand, in the case of a Q-switched laser or a pulse laser that is mechanically or electrically chopped, the output rapidly drops to 0 in a step function.
It is not necessary to limit the time immediately before the irradiation start time of the n-th laser pulse.

Next, the number of times of potential difference detection after 0.1 second from the start of laser beam injection, as shown in FIG. No change in the temperature of the semiconductor element due to the above-mentioned phenomenon is observed, so that it is not necessary to detect the potential difference for each pulse.

Here, the method of detecting the potential difference for each pulse is suitable for performing highly accurate correction. However, detecting the potential difference each time a signal is measured to obtain a temperature change is as follows.
This is nothing less than an increase in the load on the processing unit.

Therefore, the timing of detecting the potential difference after 0.1 second from the start of the laser beam incidence is such that the potential difference is detected once per second when the room temperature changes drastically, and when the room temperature hardly changes. Is preferably determined in advance in accordance with the surrounding environment, such as detecting the potential difference once every 10 seconds.

In this embodiment, when the repetition frequency of the laser pulse is from 50 Hz to 1000 Hz, the time when the semiconductor element reaches the thermal equilibrium state is 0.1 second. However, this is only an example. When the repetition frequency is 50 Hz or less or 1000 Hz or more, the time to reach the equilibrium state is not necessarily 0.1 second.

Although the present embodiment has been described using the reflected light detector, similar effects can be obtained by applying such a configuration to the incident light detector of the second embodiment. Needless to say.

However, it is very suitable for the incident light detector to be constantly irradiated with a constant laser beam that the number of times of detecting the potential difference can be reduced, but the timing of laser beam irradiation depends on the state of the machined hole. In a reflected light detector, it is needless to say that it may not be desirable to reduce the number of times of detecting the potential difference as in the case of the incident light detector in order to perform highly accurate correction.

In each of the embodiments described above, it goes without saying that the components can be appropriately combined with each other as long as the functions are not impaired.

[0183]

As described above, according to the present invention, by controlling the laser oscillator by correcting the temperature of the reflected light detector or the incident light detecting element using the semiconductor element, the hole processing of the object to be processed can be performed. Such a state can be accurately detected, and ideal hole processing can be performed. As a result, hole processing can be performed with high throughput so that conduction between adjacent conductive layers can be reliably obtained.

Here, by correcting the temperature based on the potential difference between both ends of the reflected light detector using semiconductor elements or the incident light detection element, it is possible to introduce a detector such as a thermocouple or a thermometer for the purpose of temperature measurement only. This makes it possible to achieve a simple configuration that eliminates the complexity and size of the device.

By optimizing the number of times of measuring the potential difference between both ends of the semiconductor element, highly accurate correction can be performed, and the load on the arithmetic processing unit can be reduced.

Then, the relative reflection corresponding to the intensity of the reflected light from the processed portion of the object to be processed, which is obtained by calculating from the incident light intensity detected by the incident light detector and the reflected light intensity detected by the reflected light detector. By controlling the laser oscillator based on a comparison between the light intensity and a predetermined reference value, it is possible to accurately detect a processing state substantially based on reflected light from a processing portion such as a hole processing of a processing object, By controlling the laser oscillator, ideal hole processing is performed, and as a result, hole processing can be performed with high throughput so that conduction between adjacent conductive layers can be reliably obtained.

Further, by changing the resistance value of the series resistor and the voltage value of the constant voltage source, it is possible to control the bias current of the reflected light detector and the incident light detector. Even if there is, overrange of the output from the amplifier can be avoided.

Alternatively, the magnitude of the signal input to the amplifier can be controlled by changing the resistance value of the two parallel resistors, so that the output from the amplifier can be controlled even if there is an individual difference in the reflected light detector. Over-range can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a laser processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a state of the machined hole;

FIG. 3 is a schematic diagram of a measurement system when measuring a relationship between the temperature change and an amplifier output signal.

FIG. 4 is a graph showing a relationship between the temperature change and an amplifier output signal.

FIG. 5 is a schematic diagram of a measurement system when measuring the relationship between the temperature change and the potential difference between both ends of the laser light detector.

FIG. 6 is a graph showing a relationship between the temperature change and a potential difference between both ends of the laser light detector.

FIG. 7 is a schematic diagram of a laser processing apparatus according to a second embodiment of the present invention.

FIG. 8 is a schematic diagram showing a state around a reflected light detector of the laser processing apparatus according to the third embodiment of the present invention.

FIG. 9 is a graph showing a relationship between the bias current and an amplifier output signal.

FIG. 10 is a schematic diagram showing a state around a reflected light detector of a laser processing apparatus according to a fourth embodiment of the present invention.

FIG. 11 is a schematic diagram of an output signal waveform detected by the oscilloscope according to the fifth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pulse laser oscillator 2 bend mirror 3 beam splitter 4 first scan mirror 5 second scan mirror 6 processing condensing lens 7 multilayer substrate 8 insulating layer 9 conductive layer 10 processing hole 11 moving mechanism 12 reflected light detector 13 amplifier Reference Signs List 14 arithmetic processing unit 15 control device 30 laser light detector 31 thermometer 32 oscilloscope 33 series resistance 40 beam splitter 41 incident light detector 42 amplifier 43 multilayer substrate 44 first conductive layer 45 insulating layer 46 second conductive layer 50 constant Voltage source 51 Series resistance 52 First parallel resistance 53 Second parallel resistance

Claims (19)

[Claims] A laser oscillator that emits laser light; an optical system that propagates the laser light to an object to be processed; a reflected light detector that detects the intensity of light reflected from the object to be processed;
An optical system that propagates the reflected light to the reflected light detector, and controls the laser light emitted from the laser oscillator based on a comparison between the intensity of the reflected light detected by the reflected light detector and a predetermined reference value. Laser processing having control means, wherein the reflected light detector is a semiconductor element, and further comprising correction means for correcting the intensity of the reflected light detected by the reflected light detector according to a temperature change of the semiconductor element. apparatus. 2. The laser processing apparatus according to claim 1, wherein the correction means corrects an output signal of the reflected light detector according to a temperature change detected from a potential difference between both ends of the semiconductor element. 3. The laser oscillator is a pulse laser oscillator, and when n is an integer of 2 or more, a potential difference between both ends of a semiconductor element used for correcting an n-th signal detected by a reflected light detector. 3. The laser processing apparatus according to claim 2, wherein the detection time is before the detection time of the nth signal and after the detection time of the (n−1) th signal. 4. 4. A laser oscillator that emits laser light, an incident light detector that detects the light intensity of the laser light, an optical system that propagates the laser light to an object to be processed, and a reflection from the object to be processed. A reflected light detector for detecting the intensity of light, an optical system for propagating the reflected light to the reflected light detector, an incident light intensity detected by the incident light detector, and a reflected light detected by the reflected light detector Controlling the laser light emitted from the laser oscillator based on a comparison between a predetermined reference value and a relative reflected light intensity corresponding to the intensity of the reflected light from the processing portion of the processing object, obtained by calculating from the intensity. A laser processing apparatus having control means. 5. The reflected light detector and / or the incident light detector is a semiconductor element, and the reflected light detector and / or the incident light detector detects the intensity of the reflected light and / or the incident light. 5. The laser processing apparatus according to claim 4, further comprising a correction unit that corrects according to a temperature change of the semiconductor element. 6. The reflected light detector and / or the incident light detector according to a temperature change detected from a potential difference between both ends of the semiconductor element of the reflected light detector and / or the incident light detector. 6. The laser processing apparatus according to claim 5, wherein the output signal is corrected. 7. The laser oscillator is a pulse laser oscillator, and is used to correct the n-th signal detected by the reflected light detector and / or the incident light detector when n is an integer of 2 or more. The time when the potential difference between both ends of the semiconductor element is detected is before the detection time of the n-th signal detected by the reflected light detector and / or the incident light detector, and (n−
7. The laser processing apparatus according to claim 6, wherein the time is after the detection time of the 1) th signal. 8. The laser oscillator is a pulsed laser oscillator, and the relative reflected light intensity is such that when n is an integer of 2 or more, the reflected light of each of the n-th pulsed laser light and the previous pulsed laser light. The laser processing apparatus according to claim 4, wherein the laser processing apparatus is obtained by using the intensity of the incident light and the intensity of the incident light. 9. The apparatus according to claim 1, further comprising detector signal control means for controlling the magnitude of the output signal of the reflected light detector.
The laser processing device according to any one of the above. 10. The detector signal control means has a power supply and a resistor arranged in series with the reflected light detector, and changes the voltage of the power supply and / or the resistance of the resistor to change the resistance of the reflected light detector. The laser processing apparatus according to claim 9, wherein a magnitude of the output signal is controlled. 11. The detector signal control means has a resistor arranged in parallel with the reflected light detector, and controls a magnitude of an output signal of the reflected light detector by changing a resistance value of the resistor. The laser processing device according to claim 9. 12. The laser processing apparatus according to claim 4, further comprising a detector signal control means for controlling a magnitude of an output signal of the incident light detector. 13. The detector signal control means has a power supply and a resistor arranged in series with the incident light detector, and changes the voltage of the power supply and / or the resistance of the resistor to change the resistance of the incident light detector. 13. The laser processing apparatus according to claim 12, wherein the magnitude of the output signal is controlled. 14. The detector signal control means has a resistor arranged in parallel with the incident light detector, and controls a magnitude of an output signal of the incident light detector by changing a resistance value of the resistor. The laser processing device according to claim 12. 15. An irradiation step of irradiating a laser beam emitted from a laser oscillator to a processing object, a reflected light detection step of detecting the intensity of reflected light from the processing object by using a semiconductor element, and a step of detecting the reflected light. A correction step of correcting the intensity of the reflected light detected in the detection step in accordance with a correction operation equation in accordance with a temperature change of the semiconductor element, and comparing the intensity of the reflected light corrected in the correction step with a predetermined reference value. Controlling the laser beam emitted from the laser oscillator based on the laser processing method. 16. The laser processing method according to claim 15, wherein in the correction step, the output signal of the reflected light detector is corrected in accordance with a correction operation formula according to a temperature change detected from a potential difference between both ends of the semiconductor element. 17. An irradiation step of irradiating a laser beam emitted from a laser oscillator to a processing object, an incident light detection step of detecting an intensity of the laser light, and a semiconductor element for measuring an intensity of light reflected from the processing object. The reflected light detection step to be detected using, and the intensity of the incident light detected in the incident light detection step and the intensity of the reflected light detected in the reflected light detection step, obtained by calculating from the processing object A laser processing method comprising: controlling a laser beam emitted from the laser oscillator based on a comparison between a relative reflected light intensity corresponding to an intensity of the reflected light from the processing unit and a predetermined reference value. 18. The laser processing method according to claim 17, wherein in the irradiation step, the pulse laser light is irradiated, and the relative reflected light intensity used in the control step is obtained by the following equation (1). (Equation 1) _{Here, c n = k × (b} n / a n), c max = k × (b max
/ A _max), k is an arbitrary constant, a _n is the n-th information about incident laser beam intensity b _n information about n-th reflected laser beam intensity a _max is the maximum value of information about incident laser beam intensity, b _max is the maximum value of the information on the reflected laser beam intensity, and n is an integer of 2 or more. 19. The laser processing method according to claim 15, wherein the object to be processed is a multilayer substrate on which an insulating layer and a conductive layer are stacked.