WO2017130555A1

WO2017130555A1 - Smear detection device, laser via processing device, and laser via processing method

Info

Publication number: WO2017130555A1
Application number: PCT/JP2016/085367
Authority: WO
Inventors: 成章藤原
Original assignee: 株式会社Ｓｃｒｅｅｎホールディングス
Priority date: 2016-01-29
Filing date: 2016-11-29
Publication date: 2017-08-03
Also published as: JP6636543B2; CN108449974A; JPWO2017130555A1

Abstract

An excitation light emission unit (33) of a laser via processing device (1) emits excitation light for generating fluorescent light in a resin forming an insulating layer (92) of a multilayer substrate (9). The excitation light is directed onto a main surface of the multilayer substrate (9) along a path (J1) of laser light for laser via processing, the path (J1) being perpendicular to the main surface and extending from an objective lens (322) to the main surface. An insulating layer detector receives, through the objective lens (322), the fluorescent light generated in the resin constituting the insulating layer (92), and thereby detects the presence of the insulating layer (92) in a via hole partway through being formed by laser light. It is thereby possible, in laser via processing, to accurately detect the presence of a smear in a via hole partway through being formed.

Description

Smear detection device, laser via processing device, and laser via processing method

The present invention relates to a smear detection device, a laser via processing device, and a laser via processing method.

Conventionally, laser via processing has been performed in the manufacture of a multilayer substrate in which wiring layers and insulating layers are alternately laminated. In laser via processing, by irradiating a part of the wiring layer which is the uppermost layer with laser light in a multilayer substrate under manufacturing, the wiring layer and the insulating layer below the wiring layer are penetrated, and the insulating layer A via hole (also simply referred to as a via) is formed with the lower wiring layer at the bottom. The inner surface of the via hole is plated with copper (Cu) or the like by subsequent processing, and electrical connection (conductive state) between the upper and lower wiring layers is ensured.

Note that Japanese Patent Application Laid-Open Nos. 2003-149558, 2007-38202, and 2008-147321 disclose apparatuses for correcting pattern defects on a glass substrate. In this apparatus, laser light from a laser is irradiated onto the substrate through the objective lens, and the defect is corrected. Further, light from a predetermined light source is irradiated onto the substrate via the objective lens, and the reflected light is guided to the CCD camera via the objective lens and the like, and a defect on the substrate is imaged.

By the way, in laser via processing, for example, a CO ₂ laser (carbon dioxide laser) that is not easily absorbed by the wiring layer is used. However, if the irradiation time of the laser beam is too long, depending on the thickness of the lower wiring layer, the via hole may penetrate the wiring layer, and electrical connection between the wiring layers may be difficult. On the other hand, if the laser beam irradiation time is too short, the resin residue forming the insulating layer, that is, smear, remains on the lower wiring layer, and the reliability of electrical connection between the wiring layers decreases. Actually, the etching amount is controlled to some extent by managing the irradiation time of the laser beam, but the irradiation time is managed by variations in the characteristics of the wiring material and the resin material or the thickness of each layer. However, it is not easy to properly form a via hole.

Further, after laser via processing, a visual inspection is performed using a magnifying glass or the like, and when the presence of smear is confirmed, a desmear process for removing smear is also performed. However, in laser via processing, thousands to hundreds of thousands of via holes are formed, so that a long time is required for visual inspection and a certain time is also required for desmear processing.

The present invention is directed to a smear detection device for detecting the presence of smear in a via hole in laser via processing in manufacturing a multilayer substrate in which wiring layers and insulating layers are alternately stacked. The purpose is to accurately detect the presence of smears in and to form via holes appropriately and efficiently.

The smear detection device according to the present invention emits excitation light that generates fluorescence to a resin forming an insulating layer of a multilayer substrate that is being manufactured, reaches the main surface of the multilayer substrate from the objective lens, and is perpendicular to the main surface. By receiving the excitation light emitting part irradiated with the excitation light on the main surface along the path of the laser light for laser via processing and the fluorescence generated in the resin via the objective lens, And an insulating layer detector that detects the presence of the insulating layer in a via hole that is being formed by laser light.

According to the present invention, it is possible to accurately detect the presence of smear in a via hole being formed in laser via processing. As a result, the via hole can be formed appropriately and efficiently.

In one preferred embodiment of the present invention, the smear detection device receives the reflected light of the illumination light irradiated onto the main surface along the path through the objective lens, thereby wiring in the forming via hole. A wiring layer detector for detecting the presence of the layer is further provided.

In this case, preferably, the illumination light is the laser light. More preferably, the insulating layer detection unit and the wiring layer detection unit share the same light receiving unit, and the laser light and the excitation light are switched in a predetermined order and applied to the main surface. The smear detection device may further include an end point detection unit that detects an end point of formation of the via hole based on outputs of the insulating layer detection unit and the wiring layer detection unit.

The present invention is also directed to a laser via processing apparatus that performs laser via processing in manufacturing a multilayer substrate in which wiring layers and insulating layers are alternately stacked. The laser via processing apparatus includes a laser that emits laser light for laser via processing, an optical system that guides the laser light to the main surface of a multilayer substrate that is being manufactured, and the smear detection device.

The present invention is also directed to a laser via processing method in manufacturing a multilayer substrate in which wiring layers and insulating layers are alternately laminated. The laser via processing method includes: a) irradiating laser light for laser via processing from the objective lens to the main surface of the multilayer substrate being manufactured and irradiating the main surface along a path perpendicular to the main surface; b ) A step of irradiating the main surface with excitation light that generates fluorescence in the resin forming the insulating layer of the multilayer substrate, and c) generated in the resin in parallel with the step b) And detecting the presence of the insulating layer in the via hole being formed by the laser light by receiving the fluorescent light to be received by the insulating layer detecting unit via the objective lens.

The above object and other objects, features, aspects, and advantages will become apparent from the following detailed description of the present invention with reference to the accompanying drawings.

It is a figure which shows the structure of a laser via processing apparatus. It is a figure which shows the function structure of a control part. It is a figure which shows the flow of a laser via process. It is a figure which shows the emission timing of a laser beam and excitation light. It is a figure which shows the change of reflected light intensity and fluorescence intensity. It is a figure which shows the via hole in the process of formation. It is a figure which shows the via hole in the process of formation. It is a figure which shows the via hole in the process of formation. It is a figure which shows the via hole in the process of formation.

FIG. 1 is a diagram showing a configuration of a laser via processing apparatus 1 according to an embodiment of the present invention. The laser via processing apparatus 1 performs laser via processing in manufacturing the multilayer substrate 9, that is, forms a via hole in the multilayer substrate 9 being manufactured using a laser. Laser via processing is a part of the connection process in the production of the multilayer substrate 9. In the multilayer substrate 9, for example, wiring layers 91 and insulating layers 92 are alternately laminated on a plate-like or sheet-like base material 90 made of resin. The wiring layer 91 is a wiring pattern formed of a conductive material such as copper. The insulating layer 92 is formed of a resin such as polyimide and insulates the wiring layers 91 adjacent to each other. In the following description, the multilayer substrate 9 being manufactured is simply referred to as “substrate 9”.

The laser via processing apparatus 1 includes a stage 21, a stage moving mechanism 22, a head 3, a head moving mechanism 23, and a control unit 4. The stage 21 holds the substrate 9. The stage moving mechanism 22 moves the stage 21 in the first direction along the main surface of the substrate 9. The head 3 is disposed above the substrate 9 and faces the wiring layer 91 that is the uppermost layer of the substrate 9. The head moving mechanism 23 moves the head 3 in a second direction perpendicular to the first direction and along the main surface of the substrate 9. Actually, the laser via processing apparatus 1 is provided with a plurality of heads 3 and a plurality of head moving mechanisms 23.

The head 3 includes a laser 31, a laser optical system 32, an excitation light emitting unit 33, a light receiving unit 34, and a detection optical system 35. The laser 31 is, for example, a CO ₂ laser (carbon dioxide laser), and emits laser light having a wavelength that is less absorbed by the wiring layer 91 than the insulating layer 92 and has a large reflection. The laser 31 may be another laser. The laser optical system 32 includes a collimator lens 321 and an objective lens 322. Laser light emitted from the laser 31 is guided to the main surface of the substrate 9 by the collimator lens 321 and the objective lens 322, and is condensed on the main surface. As will be described later, the laser beam is used for laser via processing. In FIG. 1, the path of the laser beam from the laser 31 to the main surface of the substrate 9 via the collimator lens 321 and the objective lens 322, that is, the optical axis of the laser optical system 32 is indicated by a one-dot chain line denoted by reference numeral J1. Yes. The path J1 is perpendicular to the main surface of the substrate 9.

The excitation light emitting unit 33 is, for example, an LED, and emits light in the ultraviolet to visible wavelength region. The light in the ultraviolet to visible wavelength region emitted from the excitation light emitting unit 33 includes light for generating fluorescence in the resin forming the insulating layer 92 (hereinafter referred to as “excitation light”), and the wiring layer 91. Then, no fluorescence is generated by the irradiation of excitation light. The detection optical system 35 includes a collimator lens 351, a dichroic mirror 352, a half mirror 353, and an imaging lens 354. Excitation light from the excitation light emitting unit 33 is guided to the dichroic mirror 352 through the collimator lens 351. The dichroic mirror 352 reflects excitation light and transmits light of other wavelengths. The excitation light reflected by the dichroic mirror 352 goes to the half mirror 353. The half mirror 353 is disposed between the collimator lens 321 and the objective lens 322 on the path J1, and the excitation light reflected by the half mirror 353 is guided to the main surface of the substrate 9 via the objective lens 322. The excitation light is approximately condensed on the main surface.

The path of the excitation light from the objective lens 322 to the main surface of the substrate 9 is almost the same as the path J1 of the laser light. Further, the irradiation position of the excitation light on the main surface of the substrate 9 is the same as the irradiation position of the laser light, and both are simply referred to as “irradiation position” in the following description. In this way, the excitation light emitted from the excitation light emitting unit 33 reaches the main surface of the substrate 9 from the objective lens 322 and irradiates the main surface along the path J1 of the laser light perpendicular to the main surface. Is done.

The light receiving unit 34 is, for example, a photodiode. Light incident on the objective lens 322 along the path J1 from the main surface of the substrate 9 is reflected by the half mirror 353 and enters the light receiving unit 34 via the dichroic mirror 352 and the imaging lens 354. Regarding visible light, the light receiving surface of the light receiving unit 34 is preferably optically conjugate with the main surface of the substrate 9. In the light receiving unit 34, a current having a magnitude corresponding to the intensity of incident light is output to the control unit 4.

In the head 3, the light path irradiated to the main surface of the substrate 9 via the objective lens 322 is perpendicular to the main surface, and the light incident on the objective lens 322 from the path and the main surface of the substrate 9. Coaxial epi-illumination that matches the path is realized. The configuration of the optical system in the head 3 may be changed as appropriate. For example, a filter that transmits or absorbs only a specific wavelength may be used.

FIG. 2 is a diagram illustrating a functional configuration of the control unit 4. FIG. 2 also shows a partial configuration of the head 3. The control unit 4 includes an emission control unit 41, an intensity detection unit 42, and an end point detection unit 43. The emission control unit 41 is connected to the excitation light emission unit 33 and the laser 31. The emission control unit 41 controls the emission timing of the excitation light from the excitation light emission unit 33 and the emission timing of the laser light from the laser 31. The intensity detector 42 is connected to the light receiver 34 and acquires the light intensity irradiated to the light receiver 34. The end point detection unit 43 detects the end point of via hole formation based on the output from the intensity detection unit 42.

FIG. 3 is a diagram showing the flow of the laser via processing by the laser via processing apparatus 1. In the laser via processing apparatus 1 of FIG. 1, when the substrate 9 is placed on the stage 21, the control unit 4 controls the stage moving mechanism 22 and the head moving mechanism 23, so that one predetermined on the substrate 9 is set. The processing position is arranged at the irradiation position (step S11). Subsequently, emission of a pulsed laser beam from the laser 31 is started under the control of the emission control unit 41, and formation of a via hole is started (step S12).

FIG. 4 is a diagram showing the emission timing of laser light and excitation light. The laser 31 is a pulse laser, and emits a pulsed laser beam as shown by a rectangle with parallel oblique lines in FIG. The laser beam is irradiated to the irradiation position on the main surface of the substrate 9 along the path J1. In parallel with the laser light irradiation, the reflected light of the laser light on the main surface is guided to the light receiving unit 34 through the objective lens 322 and the like (step S13). The output current from the light receiving unit 34 is input to the intensity detection unit 42, and the light intensity of the reflected light of the laser light (hereinafter referred to as “reflected light intensity”) is acquired. The reflected light intensity is output to the end point detection unit 43.

The reflected light intensity increases when the wiring layer 91 exists at the irradiation position. Therefore, the presence of the wiring layer 91 can be detected by acquiring the reflected light intensity. In the laser via processing apparatus 1, wiring that detects the presence of the wiring layer 91 at the irradiation position by the light receiving unit 34 that receives the reflected light of the laser light irradiated to the irradiation position and the intensity detection unit 42 that acquires the reflected light intensity A layer detector is realized.

The emission control unit 41 emits pulsed excitation light from the excitation light emission unit 33 while the emission of laser light is stopped in the laser 31, as indicated by a black rectangle in FIG. 4 (step S14). ). The excitation light is irradiated to the irradiation position on the main surface of the substrate 9 along the path J1. As described above, the excitation light generates fluorescence in the resin forming the insulating layer 92. When the resin is present at the irradiation position, in parallel with the excitation light irradiation, the fluorescence generated in the resin is guided to the light receiving unit 34 through the objective lens 322 and the like (step S15). At this time, since the dichroic mirror 352 substantially totally reflects the excitation light, the reflected light of the excitation light on the main surface of the substrate 9 is not guided to the light receiving unit 34. The output current from the light receiving unit 34 is input to the intensity detection unit 42, and fluorescence light intensity (hereinafter referred to as "fluorescence intensity") is acquired. The fluorescence intensity is output to the end point detection unit 43. When the light receiving sensitivity of the excitation light in the light receiving unit 34 is sufficiently lower than the light receiving sensitivity of light in a wavelength region other than the excitation light, a half mirror may be used instead of the dichroic mirror 352.

The fluorescence intensity increases when the insulating layer 92 formed of resin is present at the irradiation position. Therefore, it is possible to detect the presence of the insulating layer 92 by acquiring the fluorescence intensity. In the laser via processing apparatus 1, an insulating layer detection unit that detects the presence of the insulating layer 92 at the irradiation position is realized by the light receiving unit 34 that receives fluorescence caused by excitation light and the intensity detection unit 42 that acquires fluorescence intensity. The

In the laser via processing apparatus 1, the operations in steps S12 to S15, that is, emission of pulsed laser light, reception of reflected light of the laser light, emission of pulsed excitation light, and excitation light are performed. The resulting fluorescence reception is repeated alternately. In parallel with the repetition of steps S12 to S15, the end point detector 43 determines whether or not the end point of via hole formation has been detected by an algorithm described later (step S16). In FIG. 3, for the sake of illustration, step S16 is shown as a process continued from steps S12 to S15. However, as described above, the end point detection process by the end point detection unit 43 is performed in parallel with the repetition of steps S12 to S15. Done.

FIG. 5 is a diagram showing changes in the reflected light intensity and the fluorescence intensity acquired by the intensity detector 42. A line L1 in FIG. 5 indicates the reflected light intensity, and a line L2 indicates the fluorescence intensity. At time T1 immediately after the start of the formation of the via hole, as shown in FIG. 6A, only the wiring layer 91a as the uppermost layer exists at the irradiation position on the main surface of the substrate 9. Therefore, the reflected light intensity increases and the fluorescence intensity decreases. At a time T2 when a certain time has elapsed from the time T1, as shown in FIG. 6B, etching with a laser beam proceeds on the irradiation position on the main surface of the substrate 9, and the wiring layer 91a is formed on the bottom surface of the via hole 93 being formed. The portion is reduced and the insulating layer 92 is partially exposed. As a result, the reflected light intensity becomes lower than the light intensity at time T1. The fluorescence intensity is higher than the light intensity at time T1.

Thereafter, the portion of the wiring layer 91a disappears, and at the time T3, as shown in FIG. Exists. Therefore, the reflected light intensity is further lower than the light intensity at time T2. In addition, the fluorescence intensity is higher than the light intensity at time T2. As shown in FIG. 6D, the wiring layer 91b under the insulating layer 92 is exposed at the time T4 when almost no portion of the insulating layer 92 is present on the bottom surface of the via hole 93 being formed. As a result, the reflected light intensity becomes higher than the light intensity at time T3. In addition, the fluorescence intensity is lower than the light intensity at time T3.

In the end point detection unit 43, every time the reflected light intensity is input from the intensity detection unit 42, the latest set period (a preset period, for example, a period corresponding to several pulses to several tens of pulses of laser light). The average value of the reflected light intensity at is calculated. If it is confirmed that the average value becomes smaller than the second threshold value after the average value becomes smaller than the first threshold value, it is determined that the lower wiring layer 91b is exposed on the bottom surface of the via hole 93 being formed. . A first threshold value and a second threshold value, and a third threshold value and a fourth threshold value described later are set in advance.

Further, every time the fluorescence intensity is input from the intensity detector 42, the average value of the fluorescence intensity in the most recent setting period is calculated. If it is confirmed that the average value has become larger than the third threshold value and then becomes smaller than the fourth threshold value, it is determined that the insulating layer 92 has been removed on the bottom surface of the via hole 93 being formed. The state where the insulating layer 92 is removed is a state where there is no smear as a residue of the resin forming the insulating layer 92.

As described above, in the end point detection unit 43, the change in reflected light intensity and the change in fluorescence intensity are monitored in real time, the lower wiring layer 91b is exposed, and the insulating layer 92 is removed. Is confirmed, it is determined that the end point of the formation of the via hole 93 has been reached (the end point has been detected) (step S16). Thereby, the repetition of the operations of steps S12 to S15 is stopped, and the formation of the via hole 93 is completed. The diameter of the via hole 93 is, for example, several tens of μm (micrometer). Actually, each time the processing position on the substrate 9 is arranged at the irradiation position of each head 3 (step S11), the above steps S12 to S16 are performed, and the via hole 93 is formed. The end point detection unit 43 may detect the end point of formation of the via hole 93 by an algorithm different from the above.

Note that a blackened layer may be formed on the surface of the wiring layer 91a by a prior blackening process, and etching of the wiring layer 91a by laser light may be promoted. In this case, the reflected light intensity immediately after the start of laser light irradiation is lower than the example shown in FIG. 5, but the change in reflected light intensity after removal of the blackened layer at the irradiation position is the same as in FIG. . After completion of the laser via processing, the blackened layer on the wiring layer 91a is removed.

As described above, in the laser via processing by the laser via processing apparatus 1, the excitation light emitted from the excitation light emitting unit 33 is irradiated to the main surface of the substrate 9. In addition, the insulating layer detection unit realized by the light receiving unit 34 and the intensity detection unit 42 receives the fluorescence generated in the resin of the insulating layer 92 by irradiation of excitation light, and the presence of the insulating layer 92 in the via hole 93 that is being formed. Is detected. Thereby, in laser via processing, it is possible to accurately detect the presence of smear in the via hole 93 being formed. In the laser via processing device 1, a smear detection device that detects the presence of smear in the via hole 93 is realized with the excitation light emitting unit 33 and the insulating layer detection unit as main components.

Further, in the laser via processing apparatus 1, when the presence of smear is no longer detected, the appropriate via hole 93 with reduced smear is efficiently and more reliably stopped by stopping the irradiation of the substrate 9 with laser light. Can be formed. As a result, highly reliable laser via processing can be realized.

In the smear detection device, the wiring layer detection unit realized by the light receiving unit 34 and the intensity detection unit 42 receives the reflected light of the laser beam irradiated to the irradiation position, whereby the wiring layers 91a and 91b in the via hole 93 being formed are formed. Can be detected with high accuracy. In addition, the same light receiving unit 34 is shared by the insulating layer detection unit and the wiring layer detection unit, and laser light and excitation light are alternately switched and applied to the main surface of the substrate 9. Thereby, the number of parts of the smear detection device (laser via processing device 1) can be reduced as compared with the case where individual light receiving portions are provided in the insulating layer detection portion and the wiring layer detection portion.

The end point detection of the formation of the via hole 93 in the end point detection unit 43 is performed based on the outputs of both the insulating layer detection unit and the wiring layer detection unit, so that the end point can be detected with higher accuracy. Even if an abnormality such as the presence of foreign matter different from the wiring layers 91a and 91b and the insulating layer 92 occurs in the via hole 93, the via hole 93 is based on the fluorescence intensity and the reflected light intensity. It is possible to detect abnormalities in the inside.

The laser via processing device 1 and the smear detection device can be variously modified.

The wiring layer detection unit may acquire the light intensity of the reflected light of the illumination light using light emitted from another light source different from the laser 31 and the excitation light emitting unit 33 as illumination light. For example, illumination light emitted from the other light source is incident on the objective lens 322 via a half mirror or the like, similarly to the excitation light, and is irradiated onto the main surface of the substrate 9 along the path J1. The wiring layer detector receives the reflected light of the illumination light via the objective lens 322, thereby detecting the presence of the wiring layers 91a and 91b in the via hole 93 being formed. Laser light, excitation light, and illumination light are sequentially switched and applied to the substrate 9. On the other hand, in the laser via processing apparatus 1 that uses laser light emitted from the laser 31 as illumination light, the number of components can be reduced as compared with the case of using the other light sources.

The excitation light does not necessarily have to be emitted with the same period as the laser light, and may be emitted with a period N times that of the laser light (N is an integer of 2 or more), for example. That is, the laser light and the excitation light are switched in a predetermined order and applied to the main surface of the substrate 9.

It is also possible to provide separate light receiving parts in the insulating layer detection part and the wiring layer detection part. In this case, by providing an optical element (for example, a dichroic mirror) capable of separating the reflected light and the fluorescent light of the laser light in the detection optical system 35, the substrate 9 is irradiated with the laser light and the excitation light at the same time. Light intensity and fluorescence intensity may be obtained.

Depending on the design of the laser via processing apparatus 1, the irradiation position of the laser beam may be moved by a deflection unit such as a galvanometer mirror. For example, the deflecting unit is provided above a relatively large objective lens (for example, an fθ lens), and laser light and excitation light are incident on the deflecting unit alternately at the timing when the irradiation positions coincide with each other. The reflected light or the fluorescence caused by the excitation light is received by the light receiving unit through the objective lens and the deflecting unit. Also in this case, the path of the laser light from the objective lens to the main surface of the substrate 9 is perpendicular to the main surface, and coaxial epi-illumination is realized.

In the above embodiment, the end point of formation of the via hole 93 is detected based on the change in the reflected light intensity and the change in the fluorescence intensity. However, depending on the accuracy required for the end point detection, only the change in the fluorescence intensity is used. Also good.

A light receiving unit (for example, a CCD camera) in which a plurality of light receiving elements are two-dimensionally arranged may be used to acquire an image of the main surface of the substrate 9 (an image showing smear).

The configurations in the above embodiment and each modification may be combined as appropriate as long as they do not contradict each other.

Although the invention has been described in detail, the above description is illustrative and not restrictive. Therefore, it can be said that many modifications and embodiments are possible without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Laser via processing apparatus 9 Substrate 31 Laser 32 Laser optical system 33 Excitation light emitting part 34 Light receiving part 42 Intensity detection part 43 End

point detection part

91, 91a, 91b Wiring layer 92 Insulating layer 93 Via hole 322 Objective lens J1 path S11 to S16 Step

Claims

In a laser via process in manufacturing a multilayer substrate in which wiring layers and insulating layers are alternately laminated, a smear detection device that detects the presence of smear in a via hole,
A laser beam path for laser via processing that emits excitation light that generates fluorescence to the resin forming the insulating layer of the multilayer substrate in the course of production, reaches the main surface of the multilayer substrate from the objective lens, and is perpendicular to the main surface Along with the excitation light emitting part irradiated with the excitation light to the main surface,
An insulating layer detection unit that detects the presence of the insulating layer in a via hole that is being formed by the laser beam by receiving fluorescence generated in the resin through the objective lens;
Is provided.
The smear detection device according to claim 1,
It further includes a wiring layer detection unit that detects the presence of the wiring layer in the via hole being formed by receiving reflected light of the illumination light irradiated onto the main surface along the path through the objective lens.
The smear detection device according to claim 2,
The illumination light is the laser light.
The smear detection device according to claim 3,
The insulating layer detection unit and the wiring layer detection unit share the same light receiving unit,
The laser light and the excitation light are switched in a predetermined order and irradiated onto the main surface.
It is a smear detection apparatus in any one of Claim 2 thru | or 4, Comprising:
An end point detection unit that detects an end point of formation of the via hole based on outputs of the insulating layer detection unit and the wiring layer detection unit is further provided.
A laser via processing apparatus that performs laser via processing in manufacturing a multilayer substrate in which wiring layers and insulating layers are alternately stacked,
A laser that emits laser light for laser via processing;
An optical system for guiding the laser light to the main surface of the multilayer substrate under production;
A smear detection device according to any one of claims 1 to 5,
Is provided.
A laser via processing method in manufacturing a multilayer substrate in which wiring layers and insulating layers are alternately laminated,
a) irradiating the main surface with laser light for laser via processing from the objective lens to the main surface of the multilayer substrate being manufactured and along a path perpendicular to the main surface;
b) irradiating the main surface along the path with excitation light that generates fluorescence in the resin forming the insulating layer of the multilayer substrate;
c) In parallel with the step b), the insulating layer detection unit receives the fluorescence generated in the resin through the objective lens, thereby the presence of the insulating layer in the via hole that is being formed by the laser beam. Detecting
Is provided.
The laser via processing method according to claim 7,
d) The presence of the wiring layer in the via hole being formed is detected by receiving the reflected light of the illumination light applied to the main surface along the path by the wiring layer detection unit via the objective lens. The method further includes a step.
The laser via processing method according to claim 8,
The illumination light is the laser light.
The laser via processing method according to claim 9,
The insulating layer detection unit and the wiring layer detection unit share the same light receiving unit,
The laser light in the step a) and the excitation light in the step b) are switched in a predetermined order and irradiated onto the main surface.
The laser via processing method according to any one of claims 8 to 10,
The method further includes detecting an end point of formation of the via hole based on outputs of the insulating layer detection unit and the wiring layer detection unit.