JP3259695B2 - Laser processing apparatus and laser processing method - Google Patents

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. By calculating the reflected light amount ratio, the dispersion of the laser light to be processed is corrected. However, when processing a hole in a contact mask shape in which a hole is formed in advance only in the conductive layer on the substrate surface, for example, the irradiation of the laser light is performed. Depending on the relationship between the position and the hole position, the amount of light reflected by the contact mask may be different.

For example, if there is no contact mask hole that should have been opened, all laser light is reflected by the conductive layer on the surface, and the detected reflected light ratio is larger than a preset reference value. However, the laser oscillator is controlled to stop even though the desired hole is not formed.

When the inner conductive layer has a slope, the amount of light reflected from the conductive layer is smaller than that when the inner layer has no slope, and the detected reflected light ratio is a predetermined reference value. Therefore, the laser oscillator continues to emit laser light without being stopped even though a desired hole is formed.

As described above, even if the laser beam is controlled based on the comparison between the reflected light amount ratio and the constant reference value, incomplete hole drilling and damage to the conductive layer are caused, which causes a reduction in the processing yield. Would.

In view of the above points, the present invention provides a numerical value obtained by calculating from the reflected light intensity and the incident light intensity, that is, for example, the amount of increase in reflected light intensity, the rate of increase in reflected light intensity, and the normalized reflection intensity. A laser processing apparatus that realizes high-yield high-quality hole drilling by controlling the laser oscillator based on an increase in light intensity, an increase rate of normalized reflected light intensity, and a preset reference value; An object of the present invention is to provide a laser processing method.

[0016]

In order to solve the above problems, the present invention provides a reflected light detector for detecting the intensity of reflected light emitted from a laser oscillator and reflected by an object to be processed, and a reflected light detector. Increase amount of reflected light intensity and / or reflected light intensity obtained by calculating from the intensity of reflected light detected by the detector
A laser processing apparatus having control means for controlling a laser oscillator based on a comparison between a rate of increase and a predetermined reference value, or
Further, the apparatus has an incident light detector into which the laser light emitted from the laser oscillator is incident, and the control means calculates the incident light intensity detected by the incident light detector and the reflected light intensity detected by the reflected light detector. Of the normalized reflected light intensity
And / or a laser processing apparatus that controls the laser oscillator based on a comparison between an increase rate of normalized reflected light intensity and a predetermined reference value.

With such a configuration, an ideal hole is formed by precisely detecting the state of the hole drilling of the object to be processed, and controlling the laser oscillator thereafter. 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.

[0018]

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; and an optical system that propagates the reflected light to the reflected light detector. The reflected light intensity detected by the reflected light detector is represented by (Equation 1).
A laser processing apparatus for controlling a laser beam that will be emitted from the laser oscillator based on a comparison of the increase and the predetermined reference value of the reflected light intensity obtained by the arithmetic expression to be.

With such a configuration, it is possible to accurately detect the state of the hole in the object to be processed, which cannot be realized by merely comparing the intensity of the reflected light with a predetermined reference value. Is performed, and as a result, a hole can be formed so that conduction between adjacent conductive layers can be reliably obtained.

Specifically, using the reflected light intensity (Equation 1)
When numerical values calculated by the arithmetic expression is an increase amount of the reflected light intensity in indicated, because when the contact mask to the conductive layer of the surface is not empty is the intensity of the reflected light is constant, the increase in reflected light intensity the amount is always 0, etc. can be detected that the state of the hole is not normal, the processing of drilling of the workpiece
Accurately detects the processing state based on the reflected light from the part
Can be issued.

[0021]

Alternatively, as described in claim 2 , the laser light is
A laser oscillator that emits light and the laser light
Propagating optical system and intensity of light reflected from the object to be processed
And a reflected light detector for detecting the reflected light.
An optical system for propagating to the output device, and the reflected light detector
From the reflected light intensity obtained, by the operation formula shown by (Equation 2)
Comparison of required reflected light intensity increase rate with predetermined reference value
The laser light emitted from the laser oscillator based on the
It is a laser processing device that controls. With such a configuration
Is not a simple comparison between the reflected light intensity and a predetermined reference value.
Enables accurate detection of hole conditions in workpieces that cannot be achieved
And the ideal hole by controlling the laser oscillator
Processing, resulting in reliable conduction between adjacent conductive layers
Can be performed. Specifically, when the inner conductive layer has a slope, the amount of light reflected from this conductive layer is smaller than that in a case where there is no slope,
The state of the hole can be accurately detected by calculating the increase rate of the intensity of the reflected light using the arithmetic expression represented by (Equation 2).
Such as the reflected light from the drilled part of the workpiece
The processing state based on the target can be detected accurately.

[0023]

[0024] Such a configuration can also be applied to a case where the laser oscillator to normalize the reflected light intensity with the incident light intensity detected by the incident light detector to correct for variations in laser beam intensity emitted, claim 3 as noted, further comprising an incident light detector for detecting light intensity of the laser beam, the reflected light detector is normalized reflected light intensity detected by the incident light intensity detected incident light intensity detector Normalized reflected light intensity
Normalization obtained by the operation formula shown in (Equation 3)
May be a laser machining apparatus for controlling a laser beam that will be emitted from the laser oscillator based on a comparison of the increase in reflected light intensity and a predetermined reference value, if the contact mask to the conductive layer on the front surface is not vacant Since the intensity of the normalized reflected light is constant, the amount of increase in the normalized reflected light intensity is always 0, and it is possible to detect that the state of the hole is not normal .
Substantially based on the reflected light from the drilled part of the workpiece
It is possible to accurately detect the machining state based on the information .

[0025]

Alternatively, as described in claim 4 , the laser
It has an incident light detector that detects the light intensity of the light,
The reflected light detector according to the incident light intensity detected by the degree detector
Is the normalized reflected light intensity obtained by normalizing the reflected light intensity detected by
And the normalization obtained by the arithmetic expression shown in (Equation 4)
Based on a comparison between the rate of increase of the reflected light intensity and a predetermined reference value,
Laser that controls the laser light emitted from the laser oscillator.
When the inner conductive layer has a slope, the normalized reflected light intensity from the conductive layer is smaller than in the case where there is no slope. By determining the increase rate of the hole, the state of the hole can be accurately detected .
Accurately detect the machining state based on the reflected light
Can be .

[0027]

Next, the present invention is as claimed in claim 5, wherein,
An irradiation step of irradiating a laser beam emitted from the laser oscillator in the object, the intensity of the reflected light detecting step and said detected by the reflected light detecting step reflected light to detect the intensity of the reflected light from the workpiece Of the reflected light intensity obtained from
A laser processing method and a control step of controlling the increase or laser light that will be emitted from the laser oscillator based on a comparison of the rate of increase of the reflected light intensity and a predetermined reference value.

With such a configuration, it is possible to accurately detect the state of the hole in the object to be processed, which cannot be realized by merely comparing the intensity of the reflected light with a predetermined reference value. Is performed, and as a result, a hole can be formed so that conduction between adjacent conductive layers can be reliably obtained.

[0030] Or, a claim6Laser oscillation as described
For irradiating the laser beam emitted from the tool on the workpieceEngineering
AboutAnd incident light detection for detecting the intensity of the laser lightProcess
And reflection for detecting the intensity of reflected light from the object to be processed.
Light detectionProcessAnd the incident light detectionProcessIncident light detected at
Intensity and reflected light detectionProcessOf reflected light detected by
Obtained by calculating from degreesThe amount of increase in normalized reflected light intensity
Or rate of increase of normalized reflected light intensityAnd a predetermined reference value
Emitted from the laser oscillator based onToControl laser light
ControlProcessAnd a laser processing method having the following.

With such a configuration, it is possible to correct the variation in the intensity of the laser light emitted from the laser oscillator, to more accurately detect the state of the hole in the object to be processed, and to control the laser oscillator. Thus, an ideal hole can be formed, and as a result, a hole can be formed so that conduction between adjacent conductive layers can be reliably obtained.

[0032]

(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 to be processed. The multi-layer substrate includes a first conductive layer 8, an insulating layer 9, and a second conductive layer 10, and a processing hole 11 can be formed. 12
Is a mechanism for moving the multilayer substrate 7, on which the multilayer substrate 7 is placed.

Reference numeral 13 denotes a reflected light detector for detecting reflected light from the multilayer substrate 7, reference numeral 14 denotes an amplifier for amplifying a signal from the reflected light detector 13, and reference numeral 15 denotes an output signal from the reflected light detector 13. And a control device 16 for controlling the pulse laser oscillator 1, the first scanning mirror 4, and the second scanning mirror 5.

Note that 100a to 100g indicate that the pulsed output laser light oscillated from the laser
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 13 together with its optical path. 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 11 is formed in the multilayer substrate 7. This operation will be described in more detail.

First, 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, as shown by 100b and 100c, and then the first laser beam is constituted by a galvanomirror. 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 12 and incident on the multilayer substrate 7 at the processing position. Is done.

Then, processing is performed to form a processing hole 11 in the multilayer substrate 7 using the condensed output laser light as described above.

Further, a part of the laser light irradiated on the multilayer substrate 7 in this manner 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 beam detected by the reflected light detector 13 is amplified by an amplifier 14 to an arbitrary constant multiple, and then sent to an arithmetic processing unit 15 for arithmetic processing. And will be stored.

The output signal of the arithmetic processing unit 15 is sent to a control unit 16, which controls the laser oscillator 1 and the scanning mirrors 4, 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 13 will be described.

FIG. 2 shows how the processing hole 11 gradually becomes deeper. FIG. 2 (a) shows that the processing hole has not yet reached the second conductive layer 10, and FIG. 2 (b) shows the processing hole. FIG. 2C is a schematic view showing a state in which a part of the hole reaches the second conductive layer 10, and FIG. 2C is a view showing a state in which most of the processing hole reaches the second conductive layer 10.

Here, most of the reflection of the laser beam is the second
2A, the amount of reflected laser light increases in the order of FIGS. 2A, 2B, and 2C.

First, in the case of FIG. 2A, a signal relating to the light intensity of the laser beam detected by the reflected light detector 13 is sent to the arithmetic processing unit 15 via the amplifier 14 and is processed by the arithmetic processing unit 15. It is memorized.

At this time, there is no reflected light from the second conductive layer 10, but there is reflected light from the first conductive layer 8,
Assuming that the amount of laser light applied to the multilayer substrate 7 is 100%, the reflected light detector 13 detects, for example, 20% of reflected light.

In the case of FIG. 2B, since the processing has reached the second conductive layer 10, the reflected light 20% from the first conductive layer 8 and the reflected light from the second conductive layer 10 A total of 80% of reflected light, including 60%, is detected.

In the case of FIG. 2C, all the processing is completed, and the reflected light from the first conductive layer 8 is 20%.
And 80% of the reflected light from the second conductive layer 10
0% reflected light is detected.

The numerical values of these detection results are stored in the arithmetic processing unit 1
5, and the amount of increase in the reflected light intensity is obtained by the above-described equation (5).

[0056]

(Equation 5)

Using this equation, Δb2 = 80% −20
% = 60% and Δb3 = 100% −80% = 20%.

The amount of increase in the reflected light intensity is compared with a reference value preset in the arithmetic processing unit 15 to determine whether or not the processing has been completed, and sends the information to the control unit 16.

In this case, for example, if the reference value is set to 30%, since Δb3 is smaller than the reference value, the arithmetic processing unit 15 determines that the machining is completed, and the control unit 1
A command signal for not performing further laser irradiation on the hole position is sent to 6, and a command signal for stopping emission of laser light is sent to the laser oscillator 1.

Here, needless to say, 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.

Further, the same control can be performed by increasing the reflected light intensity. The numerical value of the detection result of the reflected light intensity is stored in the arithmetic processing device, respectively, and
The rate of increase in the intensity of the reflected light is calculated by the following equation.

[0062]

(Equation 6)

Using this equation, S2 = (80% −20)
%) / 80% = 0.75, S3 = (100% -80%)
A value of /100%=0.2 is obtained.

The rate of increase of the reflected light intensity is compared with a reference value preset in the arithmetic processing unit 15 to determine whether or not the processing has been completed, and sends the information to the control unit 16.

In this case, for example, if the reference value is set to 0.3, since S3 is smaller than the reference value, the arithmetic processing unit 15 determines that the machining is completed, and the control unit 16
To the hole position, a command signal for not performing the laser irradiation any more is sent, and a command signal for stopping the emission of the laser beam to the laser oscillator 1 is sent.

[0066] As described above, according to this embodiment, based on a comparison of the numerical value and a predetermined reference value obtained by calculating from the reflected light intensity, by controlling the laser beam that will be emitted from the laser oscillator In addition, it is possible to accurately detect the state of a hole to be processed, perform ideal hole processing, and as a result, perform hole processing that ensures conduction between adjacent conductive layers.

In this case, it is preferable that the numerical value obtained by calculating from the reflected light intensity is an increase amount or an increase rate of the reflected light intensity.

In this embodiment, the signal is amplified by using the amplifier. However, the magnitude of the signal sent from the laser beam detector is sufficient for the arithmetic processing unit to perform signal detection. If you have, an amplifier is not always required.

Although the laser oscillator is a pulse laser oscillator in this embodiment, a laser oscillator that emits laser light continuously may be used in some cases in relation to the object to be processed.

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 this embodiment, the fθ lens is used as the processing condensing lens. However, 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. 3 is a schematic diagram of a laser processing apparatus according to the present embodiment. In FIG. 3, the bend mirror 2 in the configuration of the first embodiment shown in FIG. 1 is replaced with a beam splitter 17, and an incident light detector 18 is provided to detect a part 100h of the output laser light transmitted through the beam splitter 17, The detection signal relating to the light intensity of the laser light detected by the photodetector 18 is amplified by an amplifier 19 to an arbitrary constant multiple, and then sent to the arithmetic processing unit 15 for processing. The configuration is similar to that of the first embodiment.

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, the reflected light intensity is processed, and processing is controlled based on the result obtained by comparing the obtained numerical value with a reference value. I have.

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.

Further, when processing a multilayer substrate having the first conductive layer 8 on the surface as shown in FIG.
Irrespective of the state, the reflected laser light 100f also includes the reflected light from the first conductive layer 8, and depending on the relationship between the irradiation position of the laser light and the hole position, it is supposed that the two laser holes 100f Even if the amount of reflected light is the same, the processing states of the two holes are different from each other, and a state where correct reflected light detection is not performed may occur.

In consideration of such a case, it is preferable to obtain the normalized reflected light intensity from the incident laser light intensity and the reflected laser light intensity.

Next, the laser oscillator 1, the scanning mirror 4, the scanning mirror 4, based on the detection signal regarding the reflected light intensity detected by the reflected light detector 13 and the detection signal regarding the incident light intensity detected by the incident light detector 18 5 will be described.

In the case of FIG. 2A, the reflected light detector 1
The signal related to the light intensity of the laser light detected at 3 is sent to the arithmetic processing unit 15 via the amplifier 14 and stored in the arithmetic processing unit 15.

At the same time, a signal relating to the light intensity of the laser light detected by the incident light detector 18 is sent to the arithmetic processing unit 15 via the amplifier 19, and the arithmetic processing unit 15 calculates the reflected light intensity based on the incident light intensity. Normalization processing is performed and stored.

At this time, there is no reflected light from the second conductive layer 10, but there is reflected light from the first conductive layer 8,
Assuming that the normalized reflected light intensity obtained by normalizing the reflected light intensity in the case of complete reflection by the incident light intensity is 1, for example, 0.2
Is calculated as the normalized reflected light intensity.
Is stored.

In the case of FIG. 2B, since the processing has reached the second conductive layer 10, the normalized reflected light intensity 0.2 from the first conductive layer 8 and the second conductive layer 10 Is stored in the arithmetic processing unit 15 as the normalized reflected light intensity, which is a total of 0.8 with the normalized reflected light intensity of 0.6.

In the case of FIG. 2C, all the processing is completed, and the normalized reflected light intensity 0.2 from the first conductive layer 8 and the normalized reflected light intensity 0.2 from the second conductive layer 10 are obtained. The numerical value of 1.0 in total with the light intensity of 0.8 is stored in the arithmetic processing unit 15 as the normalized reflected light intensity.

From the numerical values of these detection results, the arithmetic processing unit 15 determines the amount of increase in the normalized reflected light intensity by the arithmetic expression shown in (Equation 7).

[0086]

(Equation 7)

Using this equation, Δc2 = 0.8-0.
2 = 0.6 and Δc3 = 1.0−0.8 = 0.2 are obtained.

The normalized reflected light intensity increase amount is compared with a reference value set in advance in the arithmetic processing unit 15 to determine whether or not the processing has been completed.
Send to

In this case, for example, if the reference value is set to 0.3, Δc3 is smaller than the reference value, so that the arithmetic processing unit 15 determines that the machining is completed, and
A command signal for not performing further laser irradiation on the hole position is sent to 6, and a command signal for stopping emission of laser light is sent to the laser oscillator 1.

Here, needless to say, 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.

Further, the same control can be performed with the increasing rate of the normalized reflected light intensity. From the numerical value of the detection result of the normalized reflected light intensity, the arithmetic processing unit 15 obtains the increase rate of the normalized reflected light intensity by the arithmetic expression shown in (Equation 8).

[0092]

(Equation 8)

Using this equation, T2 = (0.8-0.
2) /0.8=0.75, T3 = (1.0−0.8) /
A value of 1.0 = 0.2 is obtained.

The normalized reflected light intensity increase rate is compared with a reference value preset in the arithmetic processing unit 15 to judge whether or not the processing has been completed.
Send to

In this case, for example, if the reference value is set to 0.3, since T3 is smaller than the reference value, the arithmetic processing unit 15 determines that the processing is completed, and the control unit 16
To the hole position, a command signal for not performing the laser irradiation any more is sent, and a command signal for stopping the emission of the laser beam to the laser oscillator 1 is sent.

[0096] As described above, according to this embodiment, based on a comparison of the numerical value and a predetermined reference value obtained by calculation from the incident light intensity and reflected light intensity, the laser beam that will be emitted from the laser oscillator , It is possible to accurately detect the state of the hole to be processed, perform ideal hole processing, and as a result, perform hole processing that ensures conduction between adjacent conductive layers.

In this case, the numerical value obtained by calculating from the incident light intensity and the reflected light intensity may be an increase amount or an increase rate of the normalized reflected light intensity obtained by normalizing the reflected light intensity by the incident light intensity. It is suitable.

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 detects the signal. If you have, an amplifier is not always required.

Although the laser oscillator is a pulse laser oscillator in this embodiment, a laser oscillator that continuously emits a laser beam may be used in some cases in relation to an object to be processed.

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

[0102]

As it is evident from the foregoing description, according to the present invention, based on a comparison of the numerical value and a predetermined reference value obtained by calculating from the reflected light intensity, by controlling the laser beam that will be emitted from the laser oscillator In addition, it is possible to accurately detect the state of a hole to be processed, perform ideal hole processing, and as a result, perform hole processing that ensures conduction between adjacent conductive layers.

In this case, it is preferable that the numerical value obtained by calculating from the reflected light intensity is an increase amount or an increase rate of the reflected light intensity.

[0104] Further, based on the comparison of the numerical value and a predetermined reference value obtained by calculation from the incident light intensity and reflected light intensity, also by controlling the laser beam that will be emitted from the laser oscillator, the state of the processing target hole In this case, it is possible to perform accurate hole detection, perform ideal hole processing, and as a result, perform hole processing that ensures conduction between adjacent conductive layers.

In this case, the numerical value obtained by calculating from the incident light intensity and the reflected light intensity may be an increase amount or an increase rate of the normalized reflected light intensity obtained by normalizing the reflected light intensity by the incident light intensity. It is suitable.

[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 diagram showing a state of a machined hole;

FIG. 3 is a schematic diagram of a laser processing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 pulse laser oscillator 2 bend mirror 3 beam splitter 4 first scanning mirror 5 second scanning mirror 6 processing condensing lens 7 multilayer substrate 8 first conductive layer 9 insulating layer 10 second conductive layer 11 processing hole 12 Moving mechanism 13 Reflected light detector 14 Amplifier 15 Arithmetic processing unit 16 Controller 17 Beam splitter 18 Incident light detector 19 Amplifier

Continuation of front page (56) References JP-A-10-85976 (JP, A) JP-A-64-79606 (JP, A) JP-A-8-339616 (JP, A) JP-A-4-361886 (JP) , A) JP-A-2-92482 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26/00

Claims (6)

(57) [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;
Having an optical system for propagating the reflected light to the reflected light detector, the following reflected light intensity detected by the reflected light detector :
Reflected light intensity obtained by the arithmetic expression shown in (Equation 1)
The laser processing apparatus for controlling the amount of increase and the laser beam that will be emitted from the laser oscillator based on a comparison with a predetermined reference value. (Equation 1) 2. A laser oscillator for emitting a laser beam;
An optical system for propagating the laser light to a processing object;
A reflected light detector for detecting the intensity of the reflected light from the object,
An optical system for propagating the reflected light to the reflected light detector.
Then, from the reflected light intensity detected by the reflected light detector,
Reflected light intensity obtained by the arithmetic expression shown in (Equation 2)
Laser emission based on a comparison between the rate of increase of
A laser processing device that controls laser light emitted from a shaker . (Equation 2) 3. 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 that detects the intensity of light, and an optical system that propagates the reflected light to the reflected light detector,
Normalizing said reflection light detector is normalized reflected light intensity detected by the incident light intensity the incident light intensity detector detects
From the reflected light intensity, the following equation (Formula 3) is used.
Ri increase in the normalized reflected light intensity obtained with a predetermined laser processing apparatus for controlling a laser <br/> The light that will be emitted from the laser oscillator based on a comparison with the reference value. (Equation 3) 4. A laser oscillator for emitting a laser beam;
An incident light detector for detecting the light intensity of the laser light;
An optical system for transmitting laser light to the object to be processed;
A reflected light detector for detecting the intensity of the reflected light from the object,
Having an optical system for transmitting reflected light to the reflected light detector,
According to the incident light intensity detected by the incident light intensity detector,
Normalization that normalized the reflected light intensity detected by the reflected light detector
From the reflected light intensity, the following equation (Formula 4) is used.
Of the normalized reflected light intensity and the predetermined reference value
The laser beam emitted from the laser oscillator based on the comparison with
A laser processing device that controls the light . (Equation 4) 5. 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, and a reflected light detection step. and increase in the reflected light intensity obtained by calculating from the intensity of the reflected light or a control step of controlling a laser beam that will be emitted from the laser oscillator based on a comparison of the rate of increase of the reflected light intensity and a predetermined reference value Laser processing method. 6. An irradiation step of irradiating a laser beam emitted from a laser oscillator onto a processing object, an incident light detection step of detecting the intensity of the laser light, and detecting an intensity of reflected light from the processing object. Reflected light detection step, and the incident light detection
The normal value obtained by calculating from the intensity of the incident light detected in the step and the intensity of the reflected light detected in the reflected light detecting step
Laser processing method and a control step of controlling a laser beam that will be emitted from the laser oscillator based on a comparison of the rate of increase <br/> with a predetermined reference value of the increase or normalized reflected light intensity of reflected light intensity .