WO2012035804A1 - Observation optical system and laser processing device - Google Patents

Observation optical system and laser processing device Download PDF

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Publication number
WO2012035804A1
WO2012035804A1 PCT/JP2011/056288 JP2011056288W WO2012035804A1 WO 2012035804 A1 WO2012035804 A1 WO 2012035804A1 JP 2011056288 W JP2011056288 W JP 2011056288W WO 2012035804 A1 WO2012035804 A1 WO 2012035804A1
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WIPO (PCT)
Prior art keywords
light
objective lens
lens
illumination light
optical system
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PCT/JP2011/056288
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French (fr)
Japanese (ja)
Inventor
長野　強
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オムロン株式会社
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Application filed by オムロン株式会社 filed Critical オムロン株式会社
Priority to CN201180015284.6A priority Critical patent/CN102834759B/en
Priority to KR1020127024584A priority patent/KR101385013B1/en
Publication of WO2012035804A1 publication Critical patent/WO2012035804A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/06—Means for illuminating specimens
    • G02B21/08—Condensers
    • G02B21/10—Condensers affording dark-field illumination
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/208—Filters for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/03—Observing, e.g. monitoring, the workpiece
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/36—Microscopes arranged for photographic purposes or projection purposes or digital imaging or video purposes including associated control and data processing arrangements
    • G02B21/365—Control or image processing arrangements for digital or video microscopes

Definitions

  • the present invention relates to an observation optical system and a laser processing apparatus, and more particularly, to an observation optical system and a laser processing apparatus that can favorably observe a mark for positioning an object and a light and shade pattern.
  • a bright field optical system has been used as an observation optical system used for observing an alignment mark for positioning provided on an object such as a substrate.
  • the alignment mark signal light included in the reflected light from the object is smaller than other noise lights, and the alignment mark may be observed only with low contrast.
  • a region where the scattered light of the object does not occur (hereinafter, referred to as a non-scattering region) such as a smooth flat surface becomes dark, and the grayscale pattern in that region cannot be observed. . Therefore, in order to observe the shading pattern in the non-scattering region, the optical system to be used must be switched from the dark field optical system to the bright field optical system.
  • the present invention has been made in view of such a situation, and makes it possible to satisfactorily observe both the alignment mark and the shading pattern of the object.
  • An observation optical system is an observation optical system for observing a mark for positioning an object, and forms an objective lens and illumination light emitted from a light source at the pupil of the objective lens.
  • Branch means for branching the optical path of the illumination light and the reflected light between the optical lens and the objective lens, and between the objective lens and the imaging lens, ⁇ the wavelength of the illumination light, and the positioning
  • the width of the narrowest part of the mark is w
  • at least one of light shielding means provided between the branching means and the objective lens, for blocking the reflected light that enters the numerical aperture of the objective lens within a numerical aperture of less
  • illumination light is imaged at the pupil of the objective lens, irradiated onto the object through the objective lens, and reflected light from the object is transmitted through the objective lens. Then, an image is formed by an imaging lens. In addition, illumination light or reflected light that enters within the numerical aperture range of less than about 2 ⁇ / w of the objective lens is blocked.
  • both the mark for positioning the object and the light and shade pattern can be observed well.
  • the positioning accuracy of the object is improved and the positioning time is shortened.
  • This light source is constituted by, for example, an LED.
  • This branching means is constituted by, for example, a half mirror.
  • This light shielding means is constituted by, for example, a light shielding body made of a metal plate or a light shielding body in which a light shielding film is formed on a glass plate.
  • the light shielding means may have a light shielding region having substantially the same shape as the section of the illumination light.
  • This illumination light can be monochromatic light.
  • a laser processing apparatus includes an observation optical system for observing a mark for positioning an object, and a processing optical system for irradiating the object with a processing laser beam.
  • the observation optical system includes a light source that emits illumination light, an objective lens, a condensing lens that forms an image of the illumination light on a pupil of the objective lens, and the illumination light that passes through the objective lens.
  • An imaging lens that forms an image of the reflected light from the irradiated object after passing through the objective lens, between the condenser lens and the objective lens, and the objective lens
  • a branching unit that branches the optical path of the illumination light and the reflected light, a wavelength of the illumination light is ⁇ , and a width of the narrowest portion of the positioning mark is w
  • Condensing lens and said branch hand A light shielding means for blocking the illumination light incident within a numerical aperture range of less than about 2 ⁇ / w of the objective lens, and provided between the branching means and the objective lens, And at least one of light shielding means for blocking the reflected light that is incident on the lens within a numerical aperture range of less than about 2 ⁇ / w.
  • both the mark for positioning the object and the light and shade pattern can be observed well.
  • the positioning accuracy of the object is improved and the positioning time is shortened.
  • the processing accuracy of laser processing is improved and the processing time is shortened.
  • This light source is constituted by, for example, an LED.
  • This branching means is constituted by, for example, a half mirror.
  • This light shielding means is constituted by, for example, a light shielding body made of a metal plate or a light shielding body in which a light shielding film is formed on a glass plate.
  • the laser beam can be applied to the object through the objective lens.
  • the objective lens of the observation optical system and the processing optical system can be shared, and the number of parts can be reduced.
  • the first aspect or the second aspect of the present invention it is possible to satisfactorily observe both the mark for positioning the object to be observed and the shading pattern.
  • Embodiment 2 modes for carrying out the present invention (hereinafter referred to as embodiments) will be described. The description will be given in the following order. 1. Embodiment 2. FIG. Modified example
  • FIG. 1 is a diagram showing an embodiment of an optical system of a laser processing apparatus 101 to which the present invention is applied.
  • the laser processing apparatus 101 is an apparatus that performs laser processing of an object to be processed such as a substrate.
  • the solar cell panel 102 will be described as an example of the processing object.
  • the optical system of the laser processing apparatus 101 includes a laser oscillator 111, a beam expander 112, a slit 113, an imaging lens 114, a dichroic mirror 115, an objective lens 116, an illumination device 117, a condensing lens 118, a light shield 119, and a half mirror 120. And an imaging lens 121 and a CCD (Charge-Coupled Device) camera 122.
  • the laser oscillator 111, the beam expander 112, the slit 113, the imaging lens 114, the dichroic mirror 115, and the objective lens 116 constitute a processing optical system for irradiating the solar cell panel 102 with processing laser light. Is done.
  • the objective lens 116, the illumination device 117, the condenser lens 118, the light shield 119, the half mirror 120, the imaging lens 121, and the CCD camera 122 constitute an observation optical system for observing the solar cell panel 102.
  • the laser beam emitted from the laser oscillator 111 is collimated by the beam expander 112 and collimated, and passes through the slit 113 to limit the beam diameter to a predetermined size.
  • the laser light that has passed through the slit 113 is collimated by the imaging lens 114, reflected by the dichroic mirror 115 in the direction of the objective lens 116, and collected by the objective lens 116 on the processing surface of the solar cell panel 102.
  • the laser light is scanned on the processed surface of the solar cell panel 102 by scanning means (not shown) such as a galvanometer mirror. And the processing surface of the solar cell panel 102 is processed by this laser beam.
  • the illumination device 117 includes, for example, a circular light source composed of a single color LED (Light Emitting Diode) having a predetermined wavelength (for example, 0.6 ⁇ m).
  • the light source of the present invention can be considered as a surface light source.
  • the illumination light having a circular cross section emitted from the light source of the illumination device 117 is collected by the condenser lens 118, reflected by the half mirror 120 in the direction of the objective lens 116, and imaged at the pupil of the objective lens 116.
  • the Illumination light imaged at the pupil of the objective lens 116 is Fourier transformed by the objective lens 116 and applied to the solar cell panel 102.
  • the light reflected by the solar cell panel 102 passes through the objective lens 116, the dichroic mirror 115, the half mirror 120, and the imaging lens 121 and enters the CCD camera 122. At this time, the reflected light is transmitted through the objective lens 116 and then imaged on the light receiving surface of the CCD image sensor (not shown) of the CCD camera 122 by the imaging lens 121. Imaged.
  • a light shield 119 is provided near the half mirror 120 side of the condenser lens 118.
  • the light shield 119 is obtained by processing a metal plate such as stainless steel, for example, and blocks light in the vicinity of the optical axis of the condenser lens 118 out of illumination light transmitted through the condenser lens 118.
  • the light shielding region 151A in the center.
  • the light shielding region 151A and the ring-shaped outer peripheral portion 151B are connected via linear connection portions 151C to 151F.
  • a plurality of circular openings of the same size are arranged at equal intervals in a ring shape so as to surround a substantially circular light shielding region 152A at the center.
  • the light shield 151 of FIG. 2 In addition, in the light shield 151 of FIG. 2, light incident on the connecting portions 151C to 151F is blocked, so that the brightness of the light passing through the light shield 151 varies depending on the direction from the optical axis. The light passing through 152 does not have such brightness variations and has almost uniform brightness.
  • FIG. 4 and the light shield 154 in FIG. 5 are modifications of the light shield 152 in FIG.
  • a plurality of circular openings of the same size are arranged in a double ring at equal intervals so as to surround the substantially circular light shielding region 153A at the center.
  • a plurality of circular openings are arranged in a double ring at equal intervals so as to surround a substantially circular light shielding region 154A at the center, and the outer opening is on the inner side. It is larger than the opening. In this way, by adjusting the size and arrangement of the circular openings, it is possible to adjust the size and the like of the central light shielding region.
  • FIG. 6 shows an example of the alignment mark 201 provided as a positioning mark on the solar cell panel 102.
  • the alignment mark 201 has a shape in which line segments having a width w (for example, 20 ⁇ m), a length l (for example, 120 ⁇ m), and a thickness t (for example, 2 ⁇ m) are crossed.
  • the alignment mark 201 is formed, for example, by vapor-depositing an aluminum thin film on the glass substrate of the solar cell panel 102 or by partially removing the laminated thin film in the manufacturing process of the solar cell panel 102. .
  • the alignment mark 201 is formed mainly by vapor deposition will be described.
  • NA numerical aperture
  • the first-order diffraction angle ⁇ of the diffraction grating 211 increases as the pitch p decreases, and decreases as the pitch p increases. Accordingly, the light including information on the uneven pattern on the surface of the solar cell panel 102 (having a high spatial frequency) is an angle with respect to the optical axis when viewed from the area around the objective lens 116, that is, the solar cell panel 102 (expected angle). Passes through a large area. On the other hand, the information on the uneven pattern with a rough surface (low spatial frequency) of the solar cell panel 102 passes through a central region of the objective lens 116, that is, a region with a small prospective angle.
  • FIG. 8 is a graph showing an example of an optical transfer function (hereinafter referred to as OTF) of the objective lens 116.
  • the horizontal axis represents the spatial frequency (unit: cycle / mm), and the vertical axis represents OTF.
  • a curve 221 represents an OTF curve of the entire objective lens 116, and a curve 222 is a central area (hereinafter referred to as a central area ⁇ ) of the objective lens 116 where the prospective angle ⁇ ⁇ , in other words, the objective lens.
  • an OTF curve when the central region ⁇ of the objective lens 116 is shielded that is, an OTF curve in a region around the objective lens 116 where the prospective angle ⁇ ⁇ ⁇ is obtained by subtracting the curve 222 from the curve 221.
  • the curve 231 shown in FIG. 9 is obtained.
  • the concavo-convex pattern having a spatial frequency of less than 2 / w is attenuated, and the concavo-convex pattern having the same pitch as the line width w of the alignment mark 201 is emphasized and observed. it can. As a result, the alignment mark 201 having the line width w can be emphasized and observed.
  • the laser processing apparatus 101 a part of the illumination light is blocked by the light shield 119 so that the illumination light does not enter the central region ⁇ of the objective lens 116. That is, the illumination light transmitted through the condensing lens 118 is blocked by the light shield 119 in the vicinity of the optical axis and imaged at the pupil of the objective lens 116, and then in an area outside the central area ⁇ of the objective lens 116. Incident light is applied to the solar cell panel 102.
  • the OTF characteristic of the objective lens 116 becomes substantially the same as that shown in FIG. 9, and the alignment mark 201 can be emphasized and observed.
  • the illumination light emitted from the objective lens 116 is collected as a substantially parallel wavefront on the observation surface of the solar cell panel 102, and the reflected light reflected by the observation surface is reflected on the objective lens 116.
  • FIG. 11 and 12 are enlarged views of a range 251 near the condensing point surrounded by a dotted line in FIG.
  • FIG. 11 schematically shows a state in which illumination light is incident on the solar cell panel 102 being manufactured
  • FIG. 12 schematically shows a state in which the illumination light is reflected on the solar cell panel 102 being manufactured. ing.
  • the solar cell panel 102 is configured by three layers of a layer 102A, a layer 102B, and a layer 102C from the bottom, and a power generation region is formed by the layer 102B and the layer 102C.
  • the layer 102B has a higher reflectance than the layer 102C, and a gray pattern is formed by a region where the layer 102C is formed and a region where the layer 102B appears on the surface without the layer 102C being formed.
  • the wavelength ⁇ of the illumination light is set to a value larger than the step L1 (for example, 0.3 ⁇ m) between the layer 102B and the layer 102C.
  • an alignment mark 201 is formed on the upper surface of the layer 102A in the region where the rightmost layer 102B and the layer 102C are not formed in the drawing.
  • the wavelength ⁇ of the illumination light is set to a value smaller than the step L2 (for example, 2.0 ⁇ m) between the alignment mark 201 and the layer 102A.
  • the illumination light incident at a wavefront parallel to the observation surface of the solar cell panel 102 is modulated on the observation surface of the solar cell panel 102 and becomes reflected light.
  • light and shade information is superimposed on the light reflected on the light and shade pattern formed by the layers 102B and 102C. Since the reflected light on which the grayscale information is superimposed has the step L1 of less than the wavelength ⁇ , as shown in a range 261 surrounded by a dotted line in FIG. Changes. In this figure, the change in amplitude is represented by the thickness of the line.
  • the reflected light the light reflected in the vicinity of the alignment mark 201 is superimposed with the unevenness information in addition to the shading information.
  • the reflected light on which the unevenness information is superimposed has a step L2 larger than the wavelength ⁇ , so that the amplitude changes and the reflection angle changes with respect to the incident angle as shown in the range 262 surrounded by the dotted line in FIG. To do.
  • the reflected light on which only the grayscale information is superimposed, where the incident angle ⁇ i the reflection angle ⁇ o, passes through the outside of the objective lens or is interrupted and is not observed.
  • the conventional bright field optical system a part of the reflected light on which only the grayscale information is superimposed and the reflected light on which the unevenness information is superimposed are incident on the objective lens and observed. Therefore, if the conventional bright-field optical system is used, both the shading pattern and the uneven pattern on the observation surface of the solar cell panel 102 can be observed. On the other hand, the SNR of the concavo-convex pattern on the observation surface of the solar cell panel 102 is lowered, and the alignment mark 201 cannot be observed with a high SNR compared to the dark field optical system.
  • the reflected light is incident on the objective lens 116 and observed if ⁇ ⁇ ⁇ o ⁇ ⁇ . it can.
  • both the reflected light B11 having the same reflection angle ⁇ o and the reflected light B12 having a different reflection angle ⁇ o with respect to the incident light A11 are incident on the objective lens 116 and can be observed. Therefore, it is possible to observe both the shading pattern and the uneven pattern on the observation surface of the solar cell panel 102.
  • the illumination light does not enter the central region ⁇ indicated by the oblique lines in FIG. 14, the reflected light with the reflection angle ⁇ o ⁇ ⁇ is substantially dimmed. Therefore, a component lower than the spatial frequency corresponding to the line width w of the alignment mark 201 in the uneven pattern on the observation surface of the solar cell panel 102 can be attenuated. Therefore, the alignment mark 201 can be observed with high SNR.
  • a shading pattern by laser processing may be formed in the alignment mark 201.
  • a shading pattern in the alignment mark 201 can be observed, and as a result, the alignment mark 201 can be observed more clearly.
  • both the alignment mark 201 and the light and shade pattern of the solar cell panel 102 can be observed well.
  • the alignment mark 201 can be observed well, the positioning accuracy of the solar cell panel 102 can be improved and the time required for positioning can be shortened. As a result, the processing accuracy of the solar cell panel 102 is improved and the processing time can be shortened.
  • a light source having another shape may be provided.
  • a light source that emits illumination light having a rectangular cross section may be provided.
  • the shape of the light shielding region of the light shielding body is not circular but rectangular.
  • FIG. 16 shows an example of the cross-sectional shape after the illumination light having the cross-sectional shape shown in FIG.
  • the cross section of the illumination light after passing through the condenser lens 118 has a slightly rounded corner as compared with the cross section of the illumination light in the illumination device 117.
  • FIG. 17 shows the light shielding region and the light shielding when the illumination light shown in FIG. 16 is shielded by using a light shielding body having a substantially circular light shielding region as described above with reference to FIGS.
  • An example of a region that is not performed is shown.
  • region shown with a shade in the figure has shown the area
  • illumination light having a substantially rectangular cross section is shielded by a circular light shielding region, the brightness of the illumination light after passing through the light shield varies depending on the position.
  • FIG. 19 and FIG. 20 are diagrams illustrating an example of a light shielding body that shields a central rectangular area of illumination light.
  • a rectangular light shielding region 301A is provided in the center.
  • the corners of the light shielding region 301A and the ring-shaped outer peripheral portion 301B are connected by linear support members 301C to 301F.
  • the light shield 311 in FIG. 20 is also provided with a rectangular light shield region 311A at the center.
  • the central portion of each side of the light shielding region 311A and the ring-shaped outer peripheral portion 311B are connected by linear support members 311C to 311F.
  • the shape of the light shielding region of the light shielding body is substantially the same as the shape of the cross section of the illumination light.
  • the example in which the light shielding body 119 is made of a metal plate has been shown.
  • a light shielding body in which a light shielding region such as a light shielding film is formed on a transparent member such as glass may be used.
  • a light shielding film may be directly formed on the objective lens 116 or the condenser lens 118.
  • the present invention can be applied to all apparatuses that perform positioning of an object based on alignment marks.
  • the object to be observed according to the present invention is not limited to the solar cell panel 102, and various kinds of substrates on which alignment marks are provided can be used as objects.
  • illumination light having a predetermined wavelength width
  • a representative wavelength of the illumination light for example, a peak wavelength, a center wavelength, a maximum wavelength, and the like may be used.
  • a central green wavelength 546.1 nm
  • the alignment mark can be observed more clearly when the illumination light is monochromatic light.
  • the illumination light is white light, not only the density pattern of the object but also the color of the object can be observed.
  • the shape of the alignment mark is a cruciform shape
  • the present invention is not limited to this example, and an arbitrary shape can be adopted.
  • the alignment mark has a shape other than the cross shape, for example, the width of the narrowest portion of the alignment mark is used as the width w used in the above-described equation (1).
  • the direction of the illumination light is changed by the half mirror 120 to branch the optical path of the illumination light from the illumination device 117 to the half mirror 120 and the optical path of the reflected light from the half mirror 120 to the CCD camera 122.
  • the two light paths may be branched by changing the direction of the reflected light or changing the directions of both the illumination light and the reflected light.
  • the laser oscillator 111, the illumination device 117, and the CCD camera 122 can be externally attached to the outside of the laser processing apparatus 101 separately from the laser processing apparatus 101.

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Abstract

An observation optical system with which it is possible to observe well both a shading pattern and a mark for determining the position of an object. After light emitted from the light source of a lighting device (117) passes through a condensing lens (118), is reflected by a half mirror (120), passes through a dichroic mirror (115), and forms an image in the pupil of an objective lens (116), the light then radiates a photovoltaic cell panel (102) through the objective lens (116). The light reflected from the photovoltaic cell panel (102) passes through the objective lens (116), the dichroic mirror (115), and the half mirror (120), and forms an image on an image-forming lens (121). Given that the wavelength of the light is λ and the line width of the alignment mark of the photovoltaic cell panel (102) is w, then a light shield (119) blocks light that is striking within the range of a numerical aperture less than substantially 2λ/w of the objective lens (116). The present invention can be applied to, for example, a laser processing device.

Description

観察光学系およびレーザ加工装置Observation optical system and laser processing apparatus
　本発明は、観察光学系およびレーザ加工装置に関し、特に、対象物の位置決め用の印と濃淡パターンを良好に観察できるようにした観察光学系およびレーザ加工装置に関する。 The present invention relates to an observation optical system and a laser processing apparatus, and more particularly, to an observation optical system and a laser processing apparatus that can favorably observe a mark for positioning an object and a light and shade pattern.
　従来、基板等の対象物に設けられている位置決め用のアライメントマークの観察に用いる観察光学系として、明視野光学系が用いられている。しかし、従来の明視野光学系では、対象物からの反射光に含まれるアライメントマークの信号光が、その他の雑音光に比べて小さくて、低いコントラストでしかアライメントマークを観察できないことがあった。 Conventionally, a bright field optical system has been used as an observation optical system used for observing an alignment mark for positioning provided on an object such as a substrate. However, in the conventional bright-field optical system, the alignment mark signal light included in the reflected light from the object is smaller than other noise lights, and the alignment mark may be observed only with low contrast.
　そこで、高いコントラストでアライメントマークを観察できる暗視野光学系が用いられる場合がある（例えば、特許文献１参照）。 Therefore, there is a case where a dark field optical system capable of observing the alignment mark with high contrast is used (for example, see Patent Document 1).
特開平８－３０６６０９号公報JP-A-8-306609
　しかしながら、従来の暗視野光学系では、例えば滑らかな平面など、対象物の散乱光が発生しない領域（以下、非散乱領域と称する）が真っ暗になり、その領域の濃淡パターンを観察することができない。そのため、非散乱領域の濃淡パターンを観察するためには、使用する光学系を暗視野光学系から明視野光学系に切替えなければならなかった。 However, in the conventional dark field optical system, a region where the scattered light of the object does not occur (hereinafter, referred to as a non-scattering region) such as a smooth flat surface becomes dark, and the grayscale pattern in that region cannot be observed. . Therefore, in order to observe the shading pattern in the non-scattering region, the optical system to be used must be switched from the dark field optical system to the bright field optical system.
　本発明は、このような状況に鑑みてなされたものであり、対象物のアライメントマークと濃淡パターンの両方を良好に観察できるようにするものである。 The present invention has been made in view of such a situation, and makes it possible to satisfactorily observe both the alignment mark and the shading pattern of the object.
　本発明の第１の側面の観察光学系は、対象物の位置決め用の印を観察するための観察光学系において、対物レンズと、光源から発せられる照明光を前記対物レンズの瞳において結像させる集光レンズと、前記対物レンズを介して前記照明光が照射された前記対象物からの反射光であって、前記対物レンズを透過した後の反射光を結像する結像レンズと、前記集光レンズと前記対物レンズの間、かつ、前記対物レンズと前記結像レンズの間において、前記照明光と前記反射光の光路を分岐する分岐手段と、前記照明光の波長をλ、前記位置決め用の印の最も狭い部分の幅をｗとした場合、前記集光レンズと前記分岐手段の間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記照明光を遮断する遮光手段、および、前記分岐手段と前記対物レンズの間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記反射光を遮断する遮光手段のうち少なくとも一方とを備える。 An observation optical system according to a first aspect of the present invention is an observation optical system for observing a mark for positioning an object, and forms an objective lens and illumination light emitted from a light source at the pupil of the objective lens. A condensing lens, an imaging lens that forms an image of reflected light from the object irradiated with the illumination light through the objective lens and transmitted through the objective lens, and the collecting lens; Branch means for branching the optical path of the illumination light and the reflected light between the optical lens and the objective lens, and between the objective lens and the imaging lens, λ the wavelength of the illumination light, and the positioning When the width of the narrowest part of the mark is w, the illumination light that is provided between the condenser lens and the branching unit and is incident within a numerical aperture of less than about 2λ / w of the objective lens Shading means to shut off and front And at least one of light shielding means provided between the branching means and the objective lens, for blocking the reflected light that enters the numerical aperture of the objective lens within a numerical aperture of less than about 2λ / w.
　本発明の第１の側面の観察光学系においては、照明光が、対物レンズの瞳において結像され、対物レンズを介して対象物に照射され、対象物からの反射光が、対物レンズを透過し、結像レンズにより結像される。また、対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する照明光または反射光が遮断される。 In the observation optical system according to the first aspect of the present invention, illumination light is imaged at the pupil of the objective lens, irradiated onto the object through the objective lens, and reflected light from the object is transmitted through the objective lens. Then, an image is formed by an imaging lens. In addition, illumination light or reflected light that enters within the numerical aperture range of less than about 2λ / w of the objective lens is blocked.
　従って、対象物の位置決め用の印と濃淡パターンの両方を良好に観察することができる。また、対象物の位置決め精度が向上するとともに、位置決め時間が短縮される。 Therefore, both the mark for positioning the object and the light and shade pattern can be observed well. In addition, the positioning accuracy of the object is improved and the positioning time is shortened.
　この光源は、例えば、ＬＥＤにより構成される。この分岐手段は、例えば、ハーフミラーにより構成される。この遮光手段は、例えば、金属板からなる遮光体、または、ガラス板に遮光膜を成膜した遮光体により構成される。 This light source is constituted by, for example, an LED. This branching means is constituted by, for example, a half mirror. This light shielding means is constituted by, for example, a light shielding body made of a metal plate or a light shielding body in which a light shielding film is formed on a glass plate.
　この遮光手段は、前記照明光の断面と略同じ形状の遮光領域を有するようにすることができる。 The light shielding means may have a light shielding region having substantially the same shape as the section of the illumination light.
　これにより、対象物に照射する照明光のムラをなくすることができる。 This makes it possible to eliminate unevenness in the illumination light that irradiates the object.
　この照明光は単色光にすることができる。 This illumination light can be monochromatic light.
　これにより、位置決め用の印をより鮮明に観察することができる。 This makes it possible to observe the positioning marks more clearly.
　本発明の第２の側面のレーザ加工装置は、対象物の位置決め用の印を観察するための観察光学系と、前記対象物に加工用のレーザ光を照射するための加工光学系とを備えるレーザ加工装置において、前記観察光学系は、照明光を発する光源と、対物レンズと、前記照明光を前記対物レンズの瞳において結像させる集光レンズと、前記対物レンズを介して前記照明光が照射された前記対象物からの反射光であって、前記対物レンズを透過した後の反射光を結像する結像レンズと、前記集光レンズと前記対物レンズの間、かつ、前記対物レンズと前記結像レンズの間において、前記照明光と前記反射光の光路を分岐する分岐手段と、前記照明光の波長をλ、前記位置決め用の印の最も狭い部分の幅をｗとした場合、前記集光レンズと前記分岐手段の間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記照明光を遮断する遮光手段、および、前記分岐手段と前記対物レンズの間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記反射光を遮断する遮光手段のうち少なくとも一方とを備える。 A laser processing apparatus according to a second aspect of the present invention includes an observation optical system for observing a mark for positioning an object, and a processing optical system for irradiating the object with a processing laser beam. In the laser processing apparatus, the observation optical system includes a light source that emits illumination light, an objective lens, a condensing lens that forms an image of the illumination light on a pupil of the objective lens, and the illumination light that passes through the objective lens. An imaging lens that forms an image of the reflected light from the irradiated object after passing through the objective lens, between the condenser lens and the objective lens, and the objective lens Between the imaging lenses, a branching unit that branches the optical path of the illumination light and the reflected light, a wavelength of the illumination light is λ, and a width of the narrowest portion of the positioning mark is w, Condensing lens and said branch hand A light shielding means for blocking the illumination light incident within a numerical aperture range of less than about 2λ / w of the objective lens, and provided between the branching means and the objective lens, And at least one of light shielding means for blocking the reflected light that is incident on the lens within a numerical aperture range of less than about 2λ / w.
　従って、対象物の位置決め用の印と濃淡パターンの両方を良好に観察することができる。また、対象物の位置決め精度が向上するとともに、位置決め時間が短縮される。その結果、レーザ加工の加工精度が向上するとともに、加工時間が短縮される。 Therefore, both the mark for positioning the object and the light and shade pattern can be observed well. In addition, the positioning accuracy of the object is improved and the positioning time is shortened. As a result, the processing accuracy of laser processing is improved and the processing time is shortened.
　この光源は、例えば、ＬＥＤにより構成される。この分岐手段は、例えば、ハーフミラーにより構成される。この遮光手段は、例えば、金属板からなる遮光体、または、ガラス板に遮光膜を成膜した遮光体により構成される。 This light source is constituted by, for example, an LED. This branching means is constituted by, for example, a half mirror. This light shielding means is constituted by, for example, a light shielding body made of a metal plate or a light shielding body in which a light shielding film is formed on a glass plate.
　このレーザ光は、前記対物レンズを介して前記対象物に照射されるようにすることができる。 The laser beam can be applied to the object through the objective lens.
　これにより、観察光学系と加工光学系の対物レンズを共通化することができ、部品点数を削減することができる。 Thereby, the objective lens of the observation optical system and the processing optical system can be shared, and the number of parts can be reduced.
　本発明の第１の側面または第２の側面によれば、観察する対象となる対象物の位置決め用の印と濃淡パターンの両方を良好に観察することができる。 According to the first aspect or the second aspect of the present invention, it is possible to satisfactorily observe both the mark for positioning the object to be observed and the shading pattern.
本発明を適用したレーザ加工装置の一実施の形態を示すブロック図である。It is a block diagram which shows one Embodiment of the laser processing apparatus to which this invention is applied. 遮光体の第１の例を示す図である。It is a figure which shows the 1st example of a light-shielding body. 遮光体の第２の例を示す図である。It is a figure which shows the 2nd example of a light-shielding body. 遮光体の第３の例を示す図である。It is a figure which shows the 3rd example of a light-shielding body. 遮光体の第４の例を示す図である。It is a figure which shows the 4th example of a light-shielding body. アライメントマークの例を示す図である。It is a figure which shows the example of an alignment mark. アライメントマークを観察可能にする条件を説明するための図である。It is a figure for demonstrating the conditions which make an alignment mark observable. 対物レンズのＯＴＦ特性の例を示すグラフである。It is a graph which shows the example of the OTF characteristic of an objective lens. 対物レンズの中央の領域を除いたＯＴＦ特性の例を示すグラフである。It is a graph which shows the example of the OTF characteristic except the center area | region of the objective lens. レーザ加工装置の作用効果について説明するための図である。It is a figure for demonstrating the effect of a laser processing apparatus. レーザ加工装置の作用効果について説明するための図である。It is a figure for demonstrating the effect of a laser processing apparatus. レーザ加工装置の作用効果について説明するための図である。It is a figure for demonstrating the effect of a laser processing apparatus. レーザ加工装置の作用効果について説明するための図である。It is a figure for demonstrating the effect of a laser processing apparatus. レーザ加工装置の作用効果について説明するための図である。It is a figure for demonstrating the effect of a laser processing apparatus. 照明光の断面の例を示す図である。It is a figure which shows the example of the cross section of illumination light. 集光レンズを透過した後の照明光の断面の例を示す図である。It is a figure which shows the example of the cross section of the illumination light after permeate | transmitting a condensing lens. 円形の遮光領域を有する遮光体を通過した後の照明光の断面の例を示す図である。It is a figure which shows the example of the cross section of the illumination light after passing through the light shielding body which has a circular light shielding area. 矩形の遮光領域を有する遮光体を通過した後の照明光の断面の例を示す図である。It is a figure which shows the example of the cross section of the illumination light after passing through the light shielding body which has a rectangular light shielding area. 遮光体の第５の例を示す図である。It is a figure which shows the 5th example of a light-shielding body. 遮光体の第６の例を示す図である。It is a figure which shows the 6th example of a light-shielding body.
　以下、本発明を実施するための形態（以下、実施の形態という）について説明する。なお、説明は以下の順序で行う。
１．実施の形態
２．変形例 Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described. The description will be given in the following order.
1. Embodiment 2. FIG. Modified example
＜１．実施の形態＞
［レーザ加工装置の構成例］
　図１は、本発明を適用したレーザ加工装置１０１の光学系の一実施の形態を示す図である。 <1. Embodiment>
[Configuration example of laser processing equipment]
FIG. 1 is a diagram showing an embodiment of an optical system of a laser processing apparatus 101 to which the present invention is applied.
　レーザ加工装置１０１は、基板等の加工対象物のレーザ加工を行う装置である。なお、以下、加工対象物の一例として、太陽電池パネル１０２を挙げて説明する。 The laser processing apparatus 101 is an apparatus that performs laser processing of an object to be processed such as a substrate. Hereinafter, the solar cell panel 102 will be described as an example of the processing object.
　レーザ加工装置１０１の光学系は、レーザ発振器１１１、ビームエキスパンダ１１２、スリット１１３、結像レンズ１１４、ダイクロイックミラー１１５、対物レンズ１１６、照明装置１１７、集光レンズ１１８、遮光体１１９、ハーフミラー１２０、結像レンズ１２１、および、ＣＣＤ（Charge Coupled Device）カメラ１２２を含むように構成される。そのうち、レーザ発振器１１１、ビームエキスパンダ１１２、スリット１１３、結像レンズ１１４、ダイクロイックミラー１１５、および、対物レンズ１１６により、太陽電池パネル１０２に加工用のレーザ光を照射するための加工光学系が構成される。また、対物レンズ１１６、照明装置１１７、集光レンズ１１８、遮光体１１９、ハーフミラー１２０、結像レンズ１２１、および、ＣＣＤカメラ１２２により、太陽電池パネル１０２を観察するための観察光学系が構成される。 The optical system of the laser processing apparatus 101 includes a laser oscillator 111, a beam expander 112, a slit 113, an imaging lens 114, a dichroic mirror 115, an objective lens 116, an illumination device 117, a condensing lens 118, a light shield 119, and a half mirror 120. And an imaging lens 121 and a CCD (Charge-Coupled Device) camera 122. Among them, the laser oscillator 111, the beam expander 112, the slit 113, the imaging lens 114, the dichroic mirror 115, and the objective lens 116 constitute a processing optical system for irradiating the solar cell panel 102 with processing laser light. Is done. The objective lens 116, the illumination device 117, the condenser lens 118, the light shield 119, the half mirror 120, the imaging lens 121, and the CCD camera 122 constitute an observation optical system for observing the solar cell panel 102. The
　まず、加工光学系の作用について説明する。 First, the operation of the processing optical system will be described.
　レーザ発振器１１１から射出されたレーザ光は、ビームエキスパンダ１１２によりビーム径が広げられるとともにコリメートされ、スリット１１３を通過することにより、ビーム径が所定の大きさに制限される。スリット１１３を通過したレーザ光は、結像レンズ１１４によりコリメートされ、ダイクロイックミラー１１５により対物レンズ１１６の方向に反射され、対物レンズ１１６により、太陽電池パネル１０２の加工面において集光される。また、レーザ光は、ガルバノメータミラーなどの走査手段（不図示）により、太陽電池パネル１０２の加工面上を走査される。そして、このレーザ光により、太陽電池パネル１０２の加工面が加工される。 The laser beam emitted from the laser oscillator 111 is collimated by the beam expander 112 and collimated, and passes through the slit 113 to limit the beam diameter to a predetermined size. The laser light that has passed through the slit 113 is collimated by the imaging lens 114, reflected by the dichroic mirror 115 in the direction of the objective lens 116, and collected by the objective lens 116 on the processing surface of the solar cell panel 102. The laser light is scanned on the processed surface of the solar cell panel 102 by scanning means (not shown) such as a galvanometer mirror. And the processing surface of the solar cell panel 102 is processed by this laser beam.
　次に、観察光学系の作用について説明する。 Next, the operation of the observation optical system will be described.
　照明装置１１７は、例えば、所定の波長（例えば、０．６μｍ）の単色のＬＥＤ（Light Emitting Diode）からなる円形の光源を備えている。なお、本発明の光源は面光源と考えることができる。そして、照明装置１１７の光源から射出された断面が円形の照明光は、集光レンズ１１８により集光され、ハーフミラー１２０により対物レンズ１１６の方向に反射され、対物レンズ１１６の瞳において結像される。対物レンズ１１６の瞳において結像した照明光は、対物レンズ１１６によりフーリエ変換されて、太陽電池パネル１０２に照射される。 The illumination device 117 includes, for example, a circular light source composed of a single color LED (Light Emitting Diode) having a predetermined wavelength (for example, 0.6 μm). The light source of the present invention can be considered as a surface light source. The illumination light having a circular cross section emitted from the light source of the illumination device 117 is collected by the condenser lens 118, reflected by the half mirror 120 in the direction of the objective lens 116, and imaged at the pupil of the objective lens 116. The Illumination light imaged at the pupil of the objective lens 116 is Fourier transformed by the objective lens 116 and applied to the solar cell panel 102.
　太陽電池パネル１０２において反射された光（以下、反射光と称する）は、対物レンズ１１６、ダイクロイックミラー１１５、ハーフミラー１２０、および、結像レンズ１２１を透過して、ＣＣＤカメラ１２２に入射する。このとき、反射光は、対物レンズ１１６を透過した後、結像レンズ１２１により、ＣＣＤカメラ１２２のＣＣＤイメージセンサ（不図示）の受光面上で結像され、反射光による像がＣＣＤカメラ１２２により撮像される。 The light reflected by the solar cell panel 102 (hereinafter referred to as reflected light) passes through the objective lens 116, the dichroic mirror 115, the half mirror 120, and the imaging lens 121 and enters the CCD camera 122. At this time, the reflected light is transmitted through the objective lens 116 and then imaged on the light receiving surface of the CCD image sensor (not shown) of the CCD camera 122 by the imaging lens 121. Imaged.
　また、集光レンズ１１８と対物レンズ１１６の間において、集光レンズ１１８のハーフミラー１２０側の近傍に遮光体１１９が設けられている。遮光体１１９は、例えば、ステンレス鋼などの金属板を加工したものであり、集光レンズ１１８を透過する照明光のうち、集光レンズ１１８の光軸近傍の光を遮断する。 Further, between the condenser lens 118 and the objective lens 116, a light shield 119 is provided near the half mirror 120 side of the condenser lens 118. The light shield 119 is obtained by processing a metal plate such as stainless steel, for example, and blocks light in the vicinity of the optical axis of the condenser lens 118 out of illumination light transmitted through the condenser lens 118.
［遮光体の構成例］
　ここで、図２乃至図５を参照して、レーザ加工装置１０１に用いられる遮光体の構成例について説明する。なお、図２乃至図５において、入射する照明光を遮断する遮光領域を網掛けで示している。 [Configuration example of light shielding body]
Here, with reference to FIG. 2 thru | or FIG. 5, the structural example of the light-shielding body used for the laser processing apparatus 101 is demonstrated. In FIG. 2 to FIG. 5, a light shielding region that blocks incident illumination light is shown by shading.
　図２の遮光体１５１には、円形の遮光領域１５１Ａが中央に設けられている。また、遮光領域１５１Ａを支持するために、遮光領域１５１Ａとリング状の外周部１５１Ｂとが、直線状の接続部１５１Ｃ乃至１５１Ｆを介して接続されている。この遮光体１５１の中心を集光レンズ１１８の光軸と一致するように配置することにより、集光レンズ１１８を透過する照明光のうち、集光レンズ１１８の光軸近傍の円形の遮光領域１５１Ａに入射する光が遮断される。 2 is provided with a circular light shielding region 151A in the center. In addition, in order to support the light shielding region 151A, the light shielding region 151A and the ring-shaped outer peripheral portion 151B are connected via linear connection portions 151C to 151F. By disposing the center of the light shield 151 so as to coincide with the optical axis of the condenser lens 118, among the illumination light transmitted through the condenser lens 118, a circular light shielding region 151A in the vicinity of the optical axis of the condenser lens 118. The light incident on is blocked.
　図３の遮光体１５２には、複数の同じ大きさの円形の開口部が、中央の略円形の遮光領域１５２Ａを取り囲むようにリング状に等間隔に並べられている。この遮光体１５２の中心を集光レンズ１１８の光軸と一致するように配置することにより、集光レンズ１１８を透過する照明光のうち、集光レンズ１１８の光軸近傍の略円形の遮光領域１５２Ａに入射する光が遮断される。 3, a plurality of circular openings of the same size are arranged at equal intervals in a ring shape so as to surround a substantially circular light shielding region 152A at the center. By arranging the center of the light shielding body 152 so as to coincide with the optical axis of the condensing lens 118, out of the illumination light transmitted through the condensing lens 118, a substantially circular light shielding region in the vicinity of the optical axis of the condensing lens 118. Light incident on 152A is blocked.
　また、図２の遮光体１５１では、接続部１５１Ｃ乃至１５１Ｆに入射する光が遮断されるため、遮光体１５１を通過する光の明るさに、光軸からの方向によるバラツキが生じるが、遮光体１５２を通過する光は、そのような明るさのバラツキが生じず、ほぼ均等な明るさになる。 In addition, in the light shield 151 of FIG. 2, light incident on the connecting portions 151C to 151F is blocked, so that the brightness of the light passing through the light shield 151 varies depending on the direction from the optical axis. The light passing through 152 does not have such brightness variations and has almost uniform brightness.
　図４の遮光体１５３および図５の遮光体１５４は、図３の遮光体１５２の変形例である。図４の遮光体１５３では、複数の同じ大きさの円形の開口部が、中央の略円形の遮光領域１５３Ａを取り囲むように二重にリング状に等間隔に並べられている。図５の遮光体１５４では、複数の円形の開口部が、中央の略円形の遮光領域１５４Ａを取り囲むように二重にリング状に等間隔に並べられるとともに、外側の開口部の方が内側の開口部より大きくなっている。このように、円形の開口部の大きさや配列を調整することにより、中央の遮光領域の大きさ等を調整することが可能である。 4 and the light shield 154 in FIG. 5 are modifications of the light shield 152 in FIG. In the light shielding body 153 of FIG. 4, a plurality of circular openings of the same size are arranged in a double ring at equal intervals so as to surround the substantially circular light shielding region 153A at the center. In the light shielding body 154 of FIG. 5, a plurality of circular openings are arranged in a double ring at equal intervals so as to surround a substantially circular light shielding region 154A at the center, and the outer opening is on the inner side. It is larger than the opening. In this way, by adjusting the size and arrangement of the circular openings, it is possible to adjust the size and the like of the central light shielding region.
［遮光体１１９の遮光範囲］
　次に、図６乃至図９を参照して、遮光体１１９の遮光範囲について検討する。 [Light shielding range of light shielding body 119]
Next, the light shielding range of the light shield 119 will be discussed with reference to FIGS.
　図６は、太陽電池パネル１０２に位置決め用の印として設けられているアライメントマーク２０１の例を示している。アライメントマーク２０１は、幅ｗ（例えば、２０μｍ）、長さｌ（例えば、１２０μｍ）、厚さｔ（例えば、２μｍ）の線分を十字に交差させた形状を有している。アライメントマーク２０１は、例えば、アルミニウムの薄膜を太陽電池パネル１０２のガラス基板に蒸着させたり、あるいは、太陽電池パネル１０２の製造工程において、積層された薄膜を一部除去したりすることにより形成される。なお、以下では、主に蒸着によりアライメントマーク２０１を形成した場合について説明する。 FIG. 6 shows an example of the alignment mark 201 provided as a positioning mark on the solar cell panel 102. The alignment mark 201 has a shape in which line segments having a width w (for example, 20 μm), a length l (for example, 120 μm), and a thickness t (for example, 2 μm) are crossed. The alignment mark 201 is formed, for example, by vapor-depositing an aluminum thin film on the glass substrate of the solar cell panel 102 or by partially removing the laminated thin film in the manufacturing process of the solar cell panel 102. . Hereinafter, a case where the alignment mark 201 is formed mainly by vapor deposition will be described.
　この線幅ｗのアライメントマーク２０１を観察するためには、シャノンの情報化定理により、レーザ加工装置１０１の観察光学系が、ピッチｐ≦ｗ／２の凹凸パターンを観察できる能力を有する必要がある。この条件について、図７を参照して簡単に説明する。 In order to observe the alignment mark 201 having the line width w, it is necessary that the observation optical system of the laser processing apparatus 101 has an ability to observe the concavo-convex pattern having the pitch p ≦ w / 2 according to Shannon's information theorem. . This condition will be briefly described with reference to FIG.
　図７の回折格子２１１のピッチｐ＝ｗ／２、回折格子２１１の１次の回折光の回折角をα、照明光の波長をλとすると、次式が成り立つ。 7 where the pitch p = w / 2 of the diffraction grating 211, the diffraction angle of the primary diffraction light of the diffraction grating 211 is α, and the wavelength of the illumination light is λ, the following equation holds.
　sinα＝λ／ｐ＝２λ／ｗ　・・・（１） Sin α = λ / p = 2λ / w (1)
　従って、対物レンズ１１６の空気中の開口数（ＮＡ）をsinβとすると、sinβ≧sinα＝２λ／ｗとすることにより、ピッチｐ＝ｗ／２の凹凸パターンを観察することが可能になる。なお、角度βは、対物レンズ１１６の最大見込み角である。 Therefore, when the numerical aperture (NA) of the objective lens 116 in the air is sin β, it is possible to observe an uneven pattern with a pitch p = w / 2 by setting sin β ≧ sin α = 2λ / w. Note that the angle β is the maximum expected angle of the objective lens 116.
　また、式（１）より、回折格子２１１の１次の回折角αは、ピッチｐが小さくなるほど大きくなり、ピッチｐが大きくなるほど小さくなる。従って、太陽電池パネル１０２の表面の細かい（空間周波数が高い）凹凸パターンの情報を含む光は、対物レンズ１１６の周辺の領域、すなわち、太陽電池パネル１０２から見て光軸に対する角度（見込み角）が大きな領域を通過する。一方、太陽電池パネル１０２の表面の粗い（空間周波数が低い）凹凸パターンの情報は、対物レンズ１１６の中央の領域、すなわち、見込み角が小さな領域を通過する。 Further, from the equation (1), the first-order diffraction angle α of the diffraction grating 211 increases as the pitch p decreases, and decreases as the pitch p increases. Accordingly, the light including information on the uneven pattern on the surface of the solar cell panel 102 (having a high spatial frequency) is an angle with respect to the optical axis when viewed from the area around the objective lens 116, that is, the solar cell panel 102 (expected angle). Passes through a large area. On the other hand, the information on the uneven pattern with a rough surface (low spatial frequency) of the solar cell panel 102 passes through a central region of the objective lens 116, that is, a region with a small prospective angle.
　図８は、対物レンズ１１６のOptical Transfer Function（以下、ＯＴＦと称する）の例を示すグラフである。横軸は空間周波数（単位はcycle／mm）を示し、縦軸はＯＴＦを示している。また、曲線２２１は、対物レンズ１１６全体のＯＴＦ曲線を示し、曲線２２２は、見込み角θ＜αとなる対物レンズ１１６の中央の領域（以下、中央領域αと称する）、換言すれば、対物レンズ１１６のsinα（＝２λ／ｗ）未満の開口数の範囲内の領域に対するＯＴＦ曲線を示している。ＯＴＦ曲線２２２は、ＯＴＦ曲線２２１と比較して空間周波数の帯域が狭くなり、具体的には、０から１／ｐ（＝２／ｗ）までの範囲となる。 FIG. 8 is a graph showing an example of an optical transfer function (hereinafter referred to as OTF) of the objective lens 116. The horizontal axis represents the spatial frequency (unit: cycle / mm), and the vertical axis represents OTF. A curve 221 represents an OTF curve of the entire objective lens 116, and a curve 222 is a central area (hereinafter referred to as a central area α) of the objective lens 116 where the prospective angle θ <α, in other words, the objective lens. The OTF curve for the region within the numerical aperture range of less than 116 sin α (= 2λ / w) is shown. The OTF curve 222 has a narrower spatial frequency band than the OTF curve 221. Specifically, the OTF curve 222 ranges from 0 to 1 / p (= 2 / w).
　また、対物レンズ１１６の中央領域αを遮光した場合のＯＴＦ曲線、すなわち、見込み角θ≧αとなる対物レンズ１１６の周辺の領域のＯＴＦ曲線は、曲線２２１から曲線２２２を減算することにより求められ、具体的には、図９に示される曲線２３１となる。このＯＴＦ曲線２３１は、空間周波数が１／ｐ（＝２／ｗ）においてピークとなる特性を有する。 Further, an OTF curve when the central region α of the objective lens 116 is shielded, that is, an OTF curve in a region around the objective lens 116 where the prospective angle θ ≧ α is obtained by subtracting the curve 222 from the curve 221. Specifically, the curve 231 shown in FIG. 9 is obtained. The OTF curve 231 has a characteristic in which the spatial frequency has a peak at 1 / p (= 2 / w).

　従って、対物レンズ１１６の中央領域αを遮光することにより、空間周波数が２／ｗ未満の凹凸パターンを減衰させ、アライメントマーク２０１の線幅ｗと同じピッチの凹凸パターンを強調して観察することができる。その結果、線幅ｗのアライメントマーク２０１を強調して観察することができる。
Therefore, by shielding the central region α of the objective lens 116, the concavo-convex pattern having a spatial frequency of less than 2 / w is attenuated, and the concavo-convex pattern having the same pitch as the line width w of the alignment mark 201 is emphasized and observed. it can. As a result, the alignment mark 201 having the line width w can be emphasized and observed.
　そこで、レーザ加工装置１０１では、対物レンズ１１６の中央領域αに照明光が入射しないように、遮光体１１９により照明光の一部を遮断する。すなわち、集光レンズ１１８を透過した照明光は、光軸近傍の範囲が遮光体１１９により遮断され、対物レンズ１１６の瞳において結像された後、対物レンズ１１６の中央領域αより外側の領域に入射し、太陽電池パネル１０２を照射する。従って、遮光体１１９により照明光の一部を遮断しない場合と比較して、太陽電池パネル１０２の観察面（＝加工面）の凹凸パターンのうち、空間周波数が２／ｗ未満の低周波成分が弱く励起され、空間周波数が２／ｗ以上の高周波成分がほぼ同じ強さで励起される。これにより、対物レンズ１１６のＯＴＦ特性が、実質的に図９に示されるものとほぼ同じ特性となり、アライメントマーク２０１を強調して観察することが可能になる。 Therefore, in the laser processing apparatus 101, a part of the illumination light is blocked by the light shield 119 so that the illumination light does not enter the central region α of the objective lens 116. That is, the illumination light transmitted through the condensing lens 118 is blocked by the light shield 119 in the vicinity of the optical axis and imaged at the pupil of the objective lens 116, and then in an area outside the central area α of the objective lens 116. Incident light is applied to the solar cell panel 102. Therefore, compared with the case where a part of the illumination light is not blocked by the light shielding body 119, the low-frequency component having a spatial frequency of less than 2 / w in the uneven pattern on the observation surface (= processed surface) of the solar cell panel 102 Excited weakly, high frequency components having a spatial frequency of 2 / w or more are excited with substantially the same intensity. As a result, the OTF characteristic of the objective lens 116 becomes substantially the same as that shown in FIG. 9, and the alignment mark 201 can be emphasized and observed.
［レーザ加工装置１０１の作用効果］
　ここで、図１０乃至図１４を参照して、レーザ加工装置１０１の作用効果についてさらに詳しく説明する。 [Operational effects of laser processing apparatus 101]
Here, with reference to FIG. 10 thru | or FIG. 14, the effect of the laser processing apparatus 101 is demonstrated in more detail.
　図１０に示されるように、対物レンズ１１６から射出された照明光は、太陽電池パネル１０２の観察面においてほぼ平行な波面として集光され、観察面で反射された反射光が、対物レンズ１１６に戻る。 As shown in FIG. 10, the illumination light emitted from the objective lens 116 is collected as a substantially parallel wavefront on the observation surface of the solar cell panel 102, and the reflected light reflected by the observation surface is reflected on the objective lens 116. Return.
　図１１および図１２は、図１０の点線で囲まれる集光点付近の範囲２５１の拡大図である。なお、図１１は、製作途中の太陽電池パネル１０２に照明光が入射する様子を模式的に示し、図１２は、製作途中の太陽電池パネル１０２において照明光が反射される様子を模式的に示している。 11 and 12 are enlarged views of a range 251 near the condensing point surrounded by a dotted line in FIG. FIG. 11 schematically shows a state in which illumination light is incident on the solar cell panel 102 being manufactured, and FIG. 12 schematically shows a state in which the illumination light is reflected on the solar cell panel 102 being manufactured. ing.
　図１１および図１２の例において、太陽電池パネル１０２は、下から層１０２Ａ、層１０２Ｂ、層１０２Ｃの３層により構成され、層１０２Ｂおよび層１０２Ｃにより、発電領域が形成される。層１０２Ｂは、層１０２Ｃより反射率が高く、層１０２Ｃが形成されている領域と、層１０２Ｃが形成されずに層１０２Ｂが表面に現れている領域とにより、濃淡パターンが形成される。なお、照明光の波長λは、層１０２Ｂと層１０２Ｃの間の段差Ｌ１（例えば、０．３μｍ）より大きい値に設定される。 In the example of FIGS. 11 and 12, the solar cell panel 102 is configured by three layers of a layer 102A, a layer 102B, and a layer 102C from the bottom, and a power generation region is formed by the layer 102B and the layer 102C. The layer 102B has a higher reflectance than the layer 102C, and a gray pattern is formed by a region where the layer 102C is formed and a region where the layer 102B appears on the surface without the layer 102C being formed. The wavelength λ of the illumination light is set to a value larger than the step L1 (for example, 0.3 μm) between the layer 102B and the layer 102C.
　また、図内の右端の層１０２Ｂおよび層１０２Ｃが形成されていない領域において、層１０２Ａの上面に、アライメントマーク２０１が形成されている。なお、照明光の波長λは、アライメントマーク２０１と層１０２Ａの間の段差Ｌ２（例えば、２．０μｍ）より小さい値に設定される。 Further, an alignment mark 201 is formed on the upper surface of the layer 102A in the region where the rightmost layer 102B and the layer 102C are not formed in the drawing. The wavelength λ of the illumination light is set to a value smaller than the step L2 (for example, 2.0 μm) between the alignment mark 201 and the layer 102A.
　太陽電池パネル１０２の観察面に平行な波面で入射した照明光は、太陽電池パネル１０２の観察面において変調されて反射光となる。反射光のうち、層１０２Ｂと層１０２Ｃによる形成される濃淡パターン上で反射される光には、濃淡情報が重畳される。濃淡情報が重畳された反射光は、段差Ｌ１が波長λ未満なので、図１２の点線で囲まれる範囲２６１内に示されるように、入射角に対して反射角がほとんど変化せずに、振幅だけが変化する。なお、この図では、振幅の変化を線の太さで表している。一方、反射光のうち、アライメントマーク２０１付近で反射される光には、濃淡情報に加えて凹凸情報が重畳される。凹凸情報が重畳された反射光は、段差Ｌ２が波長λより大きいので、図１２の点線で囲まれる範囲２６２内に示されるように、振幅が変化するとともに、入射角に対して反射角が変化する。 The illumination light incident at a wavefront parallel to the observation surface of the solar cell panel 102 is modulated on the observation surface of the solar cell panel 102 and becomes reflected light. Of the reflected light, light and shade information is superimposed on the light reflected on the light and shade pattern formed by the layers 102B and 102C. Since the reflected light on which the grayscale information is superimposed has the step L1 of less than the wavelength λ, as shown in a range 261 surrounded by a dotted line in FIG. Changes. In this figure, the change in amplitude is represented by the thickness of the line. On the other hand, in the reflected light, the light reflected in the vicinity of the alignment mark 201 is superimposed with the unevenness information in addition to the shading information. The reflected light on which the unevenness information is superimposed has a step L2 larger than the wavelength λ, so that the amplitude changes and the reflection angle changes with respect to the incident angle as shown in the range 262 surrounded by the dotted line in FIG. To do.
　これを、集光点近傍のニアフィールドから、対物レンズ１１６近傍のファーフィールドに立ち戻って考え、図１３に示されるように照明光Ａ１の入射角をθｉ、反射光Ｂ１の反射角をθｏとすると、太陽電池パネル１０２の観察面において濃淡情報のみが重畳され、凹凸情報が重畳されない場合、入射角θｉ＝反射角θｏとなる。一方、太陽電池パネル１０２の観察面において凹凸情報が重畳される場合、入射角θｉ≠反射角θｏとなる。 This is considered by returning from the near field near the condensing point to the far field near the objective lens 116, and when the incident angle of the illumination light A1 is θi and the reflection angle of the reflected light B1 is θo as shown in FIG. When only the density information is superimposed on the observation surface of the solar cell panel 102 and the unevenness information is not superimposed, the incident angle θi = the reflection angle θo. On the other hand, when unevenness information is superimposed on the observation surface of the solar cell panel 102, the incident angle θi is not equal to the reflection angle θo.
　従来の暗視野光学系では、入射角θｉ＝反射角θｏとなる、濃淡情報のみが重畳された反射光は、対物レンズの外側をすり抜けるか、あるいは、途中で遮断され、観察されない。一方、入射角θｉ≠反射角θｏとなる、凹凸情報が重畳された反射光は、その一部が対物レンズに入射し、途中で遮断されずに観察される。従って、従来の暗視野光学系を用いれば、高いＳＮＲで太陽電池パネル１０２の観察面の凹凸パターンを観察することができ、当然、アライメントマーク２０１も高いＳＮＲで観察することができる。一方、太陽電池パネル１０２の観察面の濃淡パターンを観察することはできない。 In the conventional dark field optical system, the reflected light on which only the grayscale information is superimposed, where the incident angle θi = the reflection angle θo, passes through the outside of the objective lens or is interrupted and is not observed. On the other hand, a part of the reflected light on which the concave / convex information is superimposed, where the incident angle θi ≠ the reflection angle θo, is incident on the objective lens and is observed without being interrupted. Therefore, if the conventional dark field optical system is used, the uneven pattern on the observation surface of the solar cell panel 102 can be observed with a high SNR, and the alignment mark 201 can also be observed with a high SNR. On the other hand, the shading pattern on the observation surface of the solar cell panel 102 cannot be observed.
　また、従来の明視野光学系では、濃淡情報のみが重畳された反射光も、凹凸情報が重畳された反射光も、その一部が対物レンズに入射し、観察される。従って、従来の明視野光学系を用いれば、太陽電池パネル１０２の観察面の濃淡パターンと凹凸パターンの両方を観察することができる。その反面、太陽電池パネル１０２の観察面の凹凸パターンのＳＮＲが低下し、暗視野光学系と比較して、アライメントマーク２０１を高いＳＮＲで観察することができない。 In the conventional bright field optical system, a part of the reflected light on which only the grayscale information is superimposed and the reflected light on which the unevenness information is superimposed are incident on the objective lens and observed. Therefore, if the conventional bright-field optical system is used, both the shading pattern and the uneven pattern on the observation surface of the solar cell panel 102 can be observed. On the other hand, the SNR of the concavo-convex pattern on the observation surface of the solar cell panel 102 is lowered, and the alignment mark 201 cannot be observed with a high SNR compared to the dark field optical system.
　一方、レーザ加工装置１０１では、反射角θｏが入射角θｉと異なるか否かに関わらず、α≦θｏ≦βの範囲内であれば、反射光が対物レンズ１１６に入射し、観察することができる。例えば、図１４の例において、入射光Ａ１１に対して反射角θｏが等しい反射光Ｂ１１および反射角θｏが異なる反射光Ｂ１２の両方とも対物レンズ１１６に入射し、観察することができる。従って、太陽電池パネル１０２の観察面の濃淡パターンと凹凸パターンの両方を観察することができる。 On the other hand, in the laser processing apparatus 101, regardless of whether or not the reflection angle θo is different from the incident angle θi, the reflected light is incident on the objective lens 116 and observed if α ≦ θo ≦ β. it can. For example, in the example of FIG. 14, both the reflected light B11 having the same reflection angle θo and the reflected light B12 having a different reflection angle θo with respect to the incident light A11 are incident on the objective lens 116 and can be observed. Therefore, it is possible to observe both the shading pattern and the uneven pattern on the observation surface of the solar cell panel 102.
　なお、図１４の反射角θｏ＞βとなる反射光Ｂ１３のような光は、対物レンズ１１６に入射しないため、従来の暗視野光学系および明視野光学系と同様に、観察することができない。 Note that light such as the reflected light B13 having a reflection angle θo> β in FIG. 14 does not enter the objective lens 116, and thus cannot be observed as in the conventional dark field optical system and bright field optical system.
　また、図１４内の斜線で示される中央領域αに照明光が入射しないため、反射角θｏ≦αとなる反射光が実質的に減光される。従って、太陽電池パネル１０２の観察面の凹凸パターンのうち、アライメントマーク２０１の線幅ｗに対応する空間周波数より低い成分を減衰することができる。従って、アライメントマーク２０１を高いＳＮＲで強調して観察することができる。 Further, since the illumination light does not enter the central region α indicated by the oblique lines in FIG. 14, the reflected light with the reflection angle θo ≦ α is substantially dimmed. Therefore, a component lower than the spatial frequency corresponding to the line width w of the alignment mark 201 in the uneven pattern on the observation surface of the solar cell panel 102 can be attenuated. Therefore, the alignment mark 201 can be observed with high SNR.
　さらに、例えば、太陽電池パネル１０２の薄膜の一部を除去することによりアライメントマーク２０１を形成した場合、レーザ加工による濃淡パターンがアライメントマーク２０１内に形成されるときがある。レーザ加工装置１０１では、このようなアライメントマーク２０１内の濃淡パターンも観察することができ、その結果、より鮮明にアライメントマーク２０１を観察することができる。 Further, for example, when the alignment mark 201 is formed by removing a part of the thin film of the solar cell panel 102, a shading pattern by laser processing may be formed in the alignment mark 201. In the laser processing apparatus 101, such a shading pattern in the alignment mark 201 can be observed, and as a result, the alignment mark 201 can be observed more clearly.
　以上のように、レーザ加工装置１０１では、太陽電池パネル１０２のアライメントマーク２０１と濃淡パターンの両方を良好に観察することができる。また、アライメントマーク２０１を良好に観察できることにより、太陽電池パネル１０２の位置決め精度が向上するとともに、位置決めに要する時間を短縮することができる。その結果、太陽電池パネル１０２の加工精度が向上するとともに、加工時間を短縮することが可能になる。 As described above, in the laser processing apparatus 101, both the alignment mark 201 and the light and shade pattern of the solar cell panel 102 can be observed well. In addition, since the alignment mark 201 can be observed well, the positioning accuracy of the solar cell panel 102 can be improved and the time required for positioning can be shortened. As a result, the processing accuracy of the solar cell panel 102 is improved and the processing time can be shortened.
＜２．変形例＞
　なお、以上の説明では、集光レンズ１１８とハーフミラー１２０の間に遮光体１１９を設ける例を示したが、ハーフミラー１２０と対物レンズ１１６の間、より厳密には、ハーフミラー１２０とダイクロイックミラー１１５の間に、対物レンズ１１６の中央領域αに入射する照明光を遮断するように遮光体を設けるようにしてもよい。これにより、対物レンズ１１６のＯＴＦ特性が、実質的に図９に示されるものとほぼ同じ特性となる。その結果、上述した実施の形態と同様に、太陽電池パネル１０２の濃淡パターンと凹凸パターンの両方を観察できるとともに、アライメントマーク２０１を強調して観察できるようになる。 <2. Modification>
In the above description, the example in which the light shielding member 119 is provided between the condensing lens 118 and the half mirror 120 has been described. However, more strictly, the half mirror 120 and the dichroic mirror are provided between the half mirror 120 and the objective lens 116. A light blocking body may be provided between the light source 115 and the illumination light incident on the central region α of the objective lens 116. As a result, the OTF characteristic of the objective lens 116 is substantially the same as that shown in FIG. As a result, as in the above-described embodiment, both the shading pattern and the uneven pattern of the solar cell panel 102 can be observed, and the alignment mark 201 can be emphasized and observed.
　また、この場合、中央領域αに入射する照明光だけでなく、太陽電池パネル１０２からの反射光のうち、対物レンズ１１６の光軸付近を通過する光も遮断することができる。従って、太陽電池パネル１０２の観察面の凹凸パターンのうち、アライメントマーク２０１の線幅ｗに対応する空間周波数より低い成分をより多く遮断することができ、アライメントマーク２０１をより強調して観察することが可能になる。 In this case, not only the illumination light incident on the central region α but also the light passing through the vicinity of the optical axis of the objective lens 116 among the reflected light from the solar cell panel 102 can be blocked. Therefore, it is possible to block more components lower than the spatial frequency corresponding to the line width w of the alignment mark 201 in the uneven pattern on the observation surface of the solar cell panel 102, and to observe the alignment mark 201 with more emphasis. Is possible.
　また、以上の説明では、照明装置１１７に円形の光源を設ける例を示したが、他の形状の光源を設けるようにしてもよい。例えば、図１５に示されるように、断面が矩形の照明光を発する光源を設けるようにしてもよい。ただし、この場合、以下に述べるように、遮光体の遮光領域の形状を円形ではなく、矩形にするのが望ましい。 In the above description, an example in which a circular light source is provided in the illumination device 117 has been shown, but a light source having another shape may be provided. For example, as shown in FIG. 15, a light source that emits illumination light having a rectangular cross section may be provided. However, in this case, as described below, it is desirable that the shape of the light shielding region of the light shielding body is not circular but rectangular.
　図１６は、断面が図１５に示される形状の照明光が集光レンズ１１８を透過した後の断面の形状の例を示している。集光レンズ１１８を透過した後の照明光の断面は、照明装置１１７における照明光の断面と比較して、角が少し丸くなっている。 FIG. 16 shows an example of the cross-sectional shape after the illumination light having the cross-sectional shape shown in FIG. The cross section of the illumination light after passing through the condenser lens 118 has a slightly rounded corner as compared with the cross section of the illumination light in the illumination device 117.
　図１７は、図１６に示される照明光を、図２乃至図５を参照して上述したような、略円形の遮光領域を有する遮光体を用いて遮光した場合において、遮光される領域と遮光されない領域の例を示している。なお、図中網掛けで示される領域が遮光される領域を示している。この図に示されるように、断面が略矩形の照明光を円形の遮光領域で遮光した場合、遮光体を通過した後の照明光の明るさに、位置によるバラツキが生じる。すなわち、照明光の断面の四隅に近づくほど、遮光体を通過する照明光が増え、四隅から遠ざかるほど、遮光体を通過する照明光が減る。従って、照明光の明るさは、断面の四隅に近づくほど明るくなり、四隅から遠ざかるほど暗くなる。その結果、太陽電池パネル１０２に照射される照明光の明るさにムラが生じる。 FIG. 17 shows the light shielding region and the light shielding when the illumination light shown in FIG. 16 is shielded by using a light shielding body having a substantially circular light shielding region as described above with reference to FIGS. An example of a region that is not performed is shown. In addition, the area | region shown with a shade in the figure has shown the area | region where light shielding is carried out. As shown in this figure, when illumination light having a substantially rectangular cross section is shielded by a circular light shielding region, the brightness of the illumination light after passing through the light shield varies depending on the position. That is, the closer to the four corners of the cross section of the illumination light, the more illumination light passes through the light shielding body, and the further away from the four corners, the less illumination light passes through the light shielding body. Therefore, the brightness of the illumination light becomes brighter as it approaches the four corners of the cross section, and becomes darker as it moves away from the four corners. As a result, unevenness occurs in the brightness of the illumination light applied to the solar cell panel 102.
　従って、図１８に示されるように、照明光の断面に合わせて、照明光の中央の矩形の領域を遮光するようにすることが望ましい。 Therefore, as shown in FIG. 18, it is desirable to block the rectangular area at the center of the illumination light in accordance with the section of the illumination light.
　図１９および図２０は、照明光の中央の矩形の領域を遮光する遮光体の例を示す図である。図１９の遮光体３０１には、矩形の遮光領域３０１Ａが中央に設けられている。また、遮光領域３０１Ａを支持するために、遮光領域３０１Ａの角部とリング状の外周部３０１Ｂとが、直線状の支持部材３０１Ｃ乃至３０１Ｆにより接続されている。図２０の遮光体３１１にも、遮光体３０１と同様に、矩形の遮光領域３１１Ａが中央に設けられている。また、遮光領域３１１Ａを支持するために、遮光領域３１１Ａの各辺の中央部とリング状の外周部３１１Ｂとが、直線状の支持部材３１１Ｃ乃至３１１Ｆにより接続されている。 FIG. 19 and FIG. 20 are diagrams illustrating an example of a light shielding body that shields a central rectangular area of illumination light. In the light shielding body 301 of FIG. 19, a rectangular light shielding region 301A is provided in the center. Further, in order to support the light shielding region 301A, the corners of the light shielding region 301A and the ring-shaped outer peripheral portion 301B are connected by linear support members 301C to 301F. Similarly to the light shield 301, the light shield 311 in FIG. 20 is also provided with a rectangular light shield region 311A at the center. Further, in order to support the light shielding region 311A, the central portion of each side of the light shielding region 311A and the ring-shaped outer peripheral portion 311B are connected by linear support members 311C to 311F.
　この遮光体３０１または遮光体３１１の中心を集光レンズ１１８の光軸と一致するように配置することにより、集光レンズ１１８を透過する照明光のうち、集光レンズ１１８の光軸近傍の矩形の遮光領域３０１Ａまたは遮光領域３１１Ａに入射する光が遮断される。 By arranging the center of the light shielding body 301 or the light shielding body 311 so as to coincide with the optical axis of the condensing lens 118, out of the illumination light transmitted through the condensing lens 118, a rectangle near the optical axis of the condensing lens 118 is obtained. The light incident on the light shielding region 301A or the light shielding region 311A is blocked.
　このように、遮光体の遮光領域の形状は、照明光の断面の形状と略同じにするのが望ましい。 Thus, it is desirable that the shape of the light shielding region of the light shielding body is substantially the same as the shape of the cross section of the illumination light.
　また、以上の説明では、遮光体１１９を金属板により構成する例を示したが、例えば、ガラスなどの透明な部材に遮光膜などによる遮光領域を形成した遮光体を用いるようにしてもよい。さらに、対物レンズ１１６または集光レンズ１１８に直接遮光膜を成膜するようにしてもよい。 In the above description, the example in which the light shielding body 119 is made of a metal plate has been shown. However, for example, a light shielding body in which a light shielding region such as a light shielding film is formed on a transparent member such as glass may be used. Further, a light shielding film may be directly formed on the objective lens 116 or the condenser lens 118.
　また、以上の説明では、本発明をレーザ加工装置１０１に適用する例を示したが、本発明は、アライメントマークに基づいて対象物の位置決めを行う装置全般に適用することが可能である。さらに、本発明の観察対象となる対象物も、太陽電池パネル１０２に限定されるものではなく、アライメントマークが設けられる各種の基板等を対象物とすることが可能である。 In the above description, the example in which the present invention is applied to the laser processing apparatus 101 has been shown. However, the present invention can be applied to all apparatuses that perform positioning of an object based on alignment marks. Furthermore, the object to be observed according to the present invention is not limited to the solar cell panel 102, and various kinds of substrates on which alignment marks are provided can be used as objects.
　また、以上の説明では、照明装置１１７の光源にＬＥＤを用いる例を示したが、他の種類の光源を用いることも可能である。 In the above description, an example in which an LED is used as the light source of the illumination device 117 has been shown, but other types of light sources may be used.
　また、以上の説明では、照明光を単色光とする例を示したが、所定の波長幅を持つ照明光を用いるようにしてもよい。この場合、上述した式（１）等に用いる照明光の波長λには、照明光の代表波長、例えば、ピーク波長、中心波長、最大波長などを用いるようにすればよい。例えば、白色光を照明光として用いる場合、中央の緑の波長（５４６．１ｎｍ）を用いることが考えられる。 In the above description, an example in which the illumination light is monochromatic light has been shown. However, illumination light having a predetermined wavelength width may be used. In this case, as the wavelength λ of the illumination light used in the above-described formula (1) and the like, a representative wavelength of the illumination light, for example, a peak wavelength, a center wavelength, a maximum wavelength, and the like may be used. For example, when white light is used as illumination light, it is conceivable to use a central green wavelength (546.1 nm).
　なお、照明光を単色光とした方が、より鮮明にアライメントマークを観察することができるようになる。一方、照明光を白色光とした場合、対象物の濃淡パターンだけでなく、対象物の色彩も観察することができるようになる。 It should be noted that the alignment mark can be observed more clearly when the illumination light is monochromatic light. On the other hand, when the illumination light is white light, not only the density pattern of the object but also the color of the object can be observed.
　さらに、以上の説明では、アライメントマークの形状を十字形にする例を示したが、この例に限定されるものではなく、任意の形状を採用することができる。なお、アライメントマークの形状を十字形以外の形状とした場合、上述した式（１）等に用いる幅ｗには、例えば、アライメントマークの最も狭い部分の幅が用いられる。 Furthermore, in the above description, an example in which the shape of the alignment mark is a cruciform shape is shown, but the present invention is not limited to this example, and an arbitrary shape can be adopted. When the alignment mark has a shape other than the cross shape, for example, the width of the narrowest portion of the alignment mark is used as the width w used in the above-described equation (1).
　また、以上の説明では、ハーフミラー１２０により照明光の方向を変えることにより、照明装置１１７からハーフミラー１２０までの照明光の光路と、ハーフミラー１２０からＣＣＤカメラ１２２までの反射光の光路を分岐する例を示したが、反射光の方向を変えたり、照明光と反射光の両方の方向を変えることにより、２つの光路を分岐するようにしてもよい。 In the above description, the direction of the illumination light is changed by the half mirror 120 to branch the optical path of the illumination light from the illumination device 117 to the half mirror 120 and the optical path of the reflected light from the half mirror 120 to the CCD camera 122. However, the two light paths may be branched by changing the direction of the reflected light or changing the directions of both the illumination light and the reflected light.
　また、レーザ発振器１１１、照明装置１１７、および、ＣＣＤカメラ１２２は、レーザ加工装置１０１とは別に、レーザ加工装置１０１の外部に外付けするようにすることも可能である。 Further, the laser oscillator 111, the illumination device 117, and the CCD camera 122 can be externally attached to the outside of the laser processing apparatus 101 separately from the laser processing apparatus 101.
　なお、本発明の実施の形態は、上述した実施の形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において種々の変更が可能である。 The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.
　１０１　レーザ加工装置
　１０２　太陽電池パネル
　１１１　レーザ発振器
　１１２　ビームエキスパンダ
　１１３　スリット
　１１４　結像レンズ
　１１５　ダイクロイックミラー
　１１６　対物レンズ
　１１７　照明装置
　１１８　集光レンズ
　１１９　遮光体
　１２０　ハーフミラー
　１２１　結像レンズ
　１２２　ＣＣＤカメラ
　１５１乃至１５４　遮光体
　１５１Ａ乃至１５４Ａ　遮光領域
　２０１　アライメントマーク
　３０１　遮光体
　３０１Ａ　遮光領域 DESCRIPTION OF SYMBOLS 101 Laser processing apparatus 102 Solar cell panel 111 Laser oscillator 112 Beam expander 113 Slit 114 Imaging lens 115 Dichroic mirror 116 Objective lens 117 Illumination apparatus 118 Condensing lens 119 Light-shielding body 120 Half mirror 121 Imaging lens 122 CCD camera 151 to 154 Light shielding body 151A to 154A Light shielding area 201 Alignment mark 301 Light shielding body 301A Light shielding area

Claims (5)

  1. 　対象物の位置決め用の印を観察するための観察光学系において、
    　対物レンズと、
    　光源から発せられる照明光を前記対物レンズの瞳において結像させる集光レンズと、
    　前記対物レンズを介して前記照明光が照射された前記対象物からの反射光であって、前記対物レンズを透過した後の反射光を結像する結像レンズと、
    　前記集光レンズと前記対物レンズの間、かつ、前記対物レンズと前記結像レンズの間において、前記照明光と前記反射光の光路を分岐する分岐手段と、
    　前記照明光の波長をλ、前記位置決め用の印の最も狭い部分の幅をｗとした場合、前記集光レンズと前記分岐手段の間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記照明光を遮断する遮光手段、および、前記分岐手段と前記対物レンズの間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記反射光を遮断する遮光手段のうち少なくとも一方と
    　を備えることを特徴とする観察光学系。     In the observation optical system for observing the mark for positioning the object,
    An objective lens;
    A condenser lens that forms an image of illumination light emitted from a light source at the pupil of the objective lens;
    An imaging lens that forms an image of the reflected light from the object irradiated with the illumination light through the objective lens and transmitted through the objective lens;
    Branch means for branching the optical path of the illumination light and the reflected light between the condenser lens and the objective lens and between the objective lens and the imaging lens;
    When the wavelength of the illumination light is λ, and the width of the narrowest portion of the positioning mark is w, the aperture is provided between the condenser lens and the branching unit and is less than about 2λ / w of the objective lens. A light shielding means for blocking the illumination light incident within a range of numbers, and the light incident between the branching means and the objective lens and incident within a numerical aperture of less than about 2λ / w of the objective lens An observation optical system comprising: at least one of light shielding means for blocking reflected light.
  2. 　前記遮光手段は、前記照明光の断面と略同じ形状の遮光領域を有する
    　ことを特徴とする請求項１に記載の観察光学系。     The observation optical system according to claim 1, wherein the light shielding unit includes a light shielding region having substantially the same shape as a section of the illumination light.
  3. 　前記照明光は単色光である
    　ことを特徴とする請求項１に記載の観察光学系。     The observation optical system according to claim 1, wherein the illumination light is monochromatic light.
  4. 　対象物の位置決め用の印を観察するための観察光学系と、前記対象物に加工用のレーザ光を照射するための加工光学系とを備えるレーザ加工装置において、
    　前記観察光学系は、
    　　照明光を発する光源と、
    　　対物レンズと、
    　　前記照明光を前記対物レンズの瞳において結像させる集光レンズと、
    　　前記対物レンズを介して前記照明光が照射された前記対象物からの反射光であって、前記対物レンズを透過した後の反射光を結像する結像レンズと、
    　　前記集光レンズと前記対物レンズの間、かつ、前記対物レンズと前記結像レンズの間において、前記照明光と前記反射光の光路を分岐する分岐手段と、
    　　前記照明光の波長をλ、前記位置決め用の印の最も狭い部分の幅をｗとした場合、前記集光レンズと前記分岐手段の間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記照明光を遮断する遮光手段、および、前記分岐手段と前記対物レンズの間に設けられ、前記対物レンズの略２λ／ｗ未満の開口数の範囲内に入射する前記反射光を遮断する遮光手段のうち少なくとも一方と
    　を備えることを特徴とするレーザ加工装置。     In a laser processing apparatus comprising: an observation optical system for observing a mark for positioning an object; and a processing optical system for irradiating the object with laser light for processing;
    The observation optical system is
    A light source that emits illumination light;
    An objective lens;
    A condenser lens that forms an image of the illumination light at the pupil of the objective lens;
    An imaging lens that forms an image of the reflected light from the object irradiated with the illumination light through the objective lens and transmitted through the objective lens;
    Branch means for branching the optical path of the illumination light and the reflected light between the condenser lens and the objective lens and between the objective lens and the imaging lens;
    When the wavelength of the illumination light is λ, and the width of the narrowest portion of the positioning mark is w, the aperture is provided between the condenser lens and the branching unit and is less than about 2λ / w of the objective lens. A light shielding means for blocking the illumination light incident within a range of numbers, and the light incident between the branching means and the objective lens and incident within a numerical aperture of less than about 2λ / w of the objective lens A laser processing apparatus comprising: at least one of light shielding means for blocking reflected light.
  5. 　前記レーザ光は、前記対物レンズを介して前記対象物に照射される
    　ことを特徴とする請求項４に記載のレーザ加工装置。     The laser processing apparatus according to claim 4, wherein the laser beam is applied to the object through the objective lens.
PCT/JP2011/056288 2010-09-14 2011-03-16 Observation optical system and laser processing device WO2012035804A1 (en)

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