KR101385013B1 - Observation optical system and laser processing device - Google Patents

Abstract

Both the mark for positioning the object and the shade pattern are observed well. Illumination light emitted from the light source of the illumination device 117 passes through the condenser lens 118, is reflected by the half mirror 120, passes through the dichroic mirror 115, and at the pupil of the objective lens 116. After the imaging, the solar panel 102 is irradiated through the objective lens 116. The reflected light from the solar panel 102 passes through the objective lens 116, the dichroic mirror 115, and the half mirror 120, and is formed by the imaging lens 121. When the light shield 119 has a wavelength of the illumination light and λ and a line width of the alignment mark of the solar panel 102 is w, the illumination light is incident within the range of the numerical aperture of less than approximately 2λ / w of the objective lens 116. To block. The present invention can be applied to, for example, a laser processing apparatus.

Description

Observation optical system and laser processing device {OBSERVATION OPTICAL SYSTEM AND LASER PROCESSING DEVICE}

BACKGROUND OF THE INVENTION Field of the Invention 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 capable of observing marks and shade patterns for positioning an object satisfactorily.

Conventionally, a bright-field optical system is used as an observation optical system used for observing alignment marks for positioning formed on an object such as a substrate. However, in the conventional bright field optical system, the signal light of the alignment mark included in the reflected light from the object is smaller than the other noise light, so that the alignment mark can only be observed with low contrast.

Therefore, the dark field optical system which can observe an alignment mark with high contrast may be used (for example, refer patent document 1).

Prior art literature

Patent Document 1: Japanese Patent Application Laid-open No. Hei 8-306609

However, in the conventional dark field optical system, a region (hereinafter, referred to as a non-scattered region) in which scattered light of an object, such as a smooth plane, does not occur, is darkened, and a light pattern of the region cannot be observed. For this reason, in order to observe the light-dark pattern of a non-scattering area | region, it was necessary to switch the optical system to be used from the dark field optical system to the bright field optical system.

This invention is made | formed in view of such a situation, and the objective of this invention is to make it possible to observe both the alignment mark of a target and a light and shade pattern favorably.

The observation optical system according to the first aspect of the present invention is an observation optical system for observing a mark for positioning an object, wherein the condensing lens forms an illumination light emitted from an objective lens and a light source in the pupil of the objective lens, the objective An imaging lens that forms reflected light after passing through the objective lens as reflected light from the object to which the illumination light is irradiated through the lens, the illumination light between the condenser lens and the objective lens, and between the objective lens and the imaging lens And a branching means for branching the optical path of the reflected light and a wavelength of the illumination light as λ and a width of the narrowest portion of the mark for positioning, w is provided between the condensing lens and the branching means. A difference for blocking the illumination light incident within a range of a numerical aperture of less than approximately 2λ / w of the objective lens Means, and is provided between said branch means and the objective lens, at least comprising a one-way from the light-blocking means for blocking the reflected light that enters the range of the numerical aperture of less than about 2λ / w of the objective lens.

In the observation optical system according to the first aspect of the present invention, illumination light is formed in the pupil of the objective lens, irradiated to the object through the objective lens, and reflected light from the object passes through the objective lens and is formed by the imaging lens. do. Further, illumination light or reflected light incident within a range of a numerical aperture of less than approximately 2λ / w of the objective lens is blocked.

Therefore, both the mark for positioning the object and the light and shade pattern can be observed satisfactorily. In addition, the positioning accuracy of the object is improved, and the positioning time is shortened.

The said light source is comprised by LED, for example. The said branching means is comprised by a half mirror, for example. The said light shielding means is comprised by the light shielding body which formed the light shielding film into the light shielding body or glass plate which consists of metal plates, for example.

The light blocking means may have a light blocking area having a shape substantially the same as that of the cross section of the illumination light.

Thereby, the nonuniformity of the illumination light irradiated to an object can be eliminated.

The illumination light can be monochromatic light.

Thereby, the mark for positioning can be observed more clearly.

In the laser processing apparatus according to the second aspect of the present invention, the laser processing apparatus includes an observation optical system for observing a mark for positioning an object, and a processing optical system for irradiating a laser beam for processing to the object. The observation optical system includes a light source that emits illumination light, an objective lens, a condenser lens that forms the illumination light at the pupil of the objective lens, and reflected light after passing through the objective lens as reflected light from the object to which the illumination light is irradiated through the objective lens. An imaging lens for forming, a branching means for branching the illumination path between the condensing lens and the objective lens and between the objective lens and the imaging lens and the wavelength of the illumination light, and the wavelength of the illumination light is? When the width of the narrowest part of the mark is w, the condensing lens and the A light shielding means provided between the means and blocking the illumination light incident within a range of a numerical aperture of less than approximately 2λ / w of the objective lens, and between the branching means and the objective lens, At least one of the light shielding means which interrupts the said reflected light which injects in the range of numerical aperture of less than about 2 (lambda) / w is provided.

Therefore, both the mark for positioning the object and the light and shade pattern can be observed satisfactorily. In addition, the positioning accuracy of the object is improved, and the positioning time is shortened. As a result, the machining precision of laser processing is improved and the machining time is shortened.

The said light source is comprised by LED, for example. The said branching means is comprised by a half mirror, for example. The said light shielding means is comprised by the light shielding body which formed the light shielding film into the light shielding body or glass plate which consists of metal plates, for example.

The laser light may be irradiated to the object through the objective lens.

Thereby, the objective lens of an observation optical system and a processing optical system can be made common, and the number of component parts can be reduced.

According to the 1st side or 2nd side of this invention, both the mark for positioning of the target object to be observed, and the light and shade pattern can be observed favorably.

1 is a block diagram showing an embodiment of a laser processing apparatus to which the present invention is applied.
2 is a diagram illustrating a first example of a light shielding body.
3 is a diagram illustrating a second example of a light shield.
4 is a diagram illustrating a third example of the light shielding body.
5 is a diagram illustrating a fourth example of the light shielding body.
6 is a diagram illustrating an example of an alignment mark.
It is a figure for demonstrating the conditions which make an alignment mark observable.
8 is a graph showing an example of an optical transfer function (OTF) characteristic of an objective lens.
9 is a graph showing an example of an optical transfer function (OTF) characteristic except for the center region of the objective lens.
It is a figure for demonstrating the effect of a laser processing apparatus.
It is a figure for demonstrating the effect of a laser processing apparatus.
It is a figure for demonstrating the effect of a laser processing apparatus.
It is a figure for demonstrating the effect of a laser processing apparatus.
It is a figure for demonstrating the effect of a laser processing apparatus.
15 is a diagram illustrating an example of a cross section of illumination light.
16 is a diagram illustrating an example of a cross section of illumination light after passing through a condenser lens.
It is a figure which shows the example of the cross section of illumination light after passing through the light shielding body which has a circular light shielding area | region.
18 is a diagram illustrating an example of a cross section of illumination light after passing through a light shielding body having a rectangular light shielding region.
19 is a diagram illustrating a fifth example of the light shielding body.
20 is a diagram illustrating a sixth example of the light shielding body.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth an embodiment) for implementing this invention is demonstrated. The description will be made in the following order.

1. Embodiment

2. Modification

1. Embodiment

Configuration example of the laser processing device

1 is a diagram showing an embodiment of an optical system of the laser processing apparatus 101 to which the present invention is applied.

The laser processing apparatus 101 is an apparatus which performs the laser processing of objects of processing, such as a board | substrate. In addition, below, the solar cell panel 102 is mentioned and demonstrated as an example of a process object.

The optical system of the laser processing apparatus 101 includes a laser oscillator 111, beam expanders 112, slits 113, an imaging lens 114, a dichroic mirror 115, an objective lens. 116, an illumination device 117, a condenser lens 118, a light shield 119, a half mirror 120, an imaging lens 121, and a charge coupled device (CCD) 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 are used for processing the solar panel 102. A processing optical system for irradiating the laser light is configured. In addition, the solar panel (B) by the objective lens 116, the lighting device 117, the condenser lens 118, the light shield 119, the half mirror 120, the imaging lens 121, and the CCD camera 122. An observation optical system for observing 102 is configured.

First, the operation of the processing optical system will be described.

The laser beam emitted from the laser oscillator 111 is widened and collimated by the beam expander 112 and collimated to pass through the slit 113, whereby the beam diameter is limited to a predetermined size. The laser light passing 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 by the objective lens 116. The light is collected at the processed surface of the panel 102. In addition, 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 process surface of the solar cell panel 102 is processed by the said laser beam.

Next, the operation of the observation optical system will be described.

The lighting apparatus 117 is provided with the circular light source which consists of a monochromatic LED (Light Emitting Diode) of a predetermined | prescribed wavelength (for example, 0.6 m), for example. In addition, the light source of this invention can be considered as a surface light source. In addition, 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, and is reflected by the half mirror 120 in the direction of the objective lens 116 to provide the objective lens 116. Is formed in the pupil. Illumination light formed in the pupil of the objective lens 116 is Fourier transformed by the objective lens 116 and irradiated to the solar panel 102.

The light reflected from the solar 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 to transmit the CCD camera 122. ) Is incident. At this time, the reflected light is transmitted through the objective lens 116, and then formed on the light receiving surface of the CCD image sensor (not shown) of the CCD camera 122 by the imaging lens 121, the image by the reflected light is CCD It is picked up by the camera 122.

A light shielding body 119 is provided between the condenser lens 118 and the objective lens 116 in the vicinity of the half mirror 120 side of the condenser lens 118. The light shielding body 119 processes the metal plate, such as stainless steel, for example, and interrupts the light of the vicinity of the optical axis of the light condensing lens 118 among the illumination light which permeate | transmits the light condensing lens 118.

Structure example of light shield

Here, with reference to FIGS. 2-5, the structural example of the light shielding body used for the laser processing apparatus 101 is demonstrated. In addition, in FIG. 2-5, the light shielding area which interrupts the incident illumination light is shown by the net shape.

In the light shielding body 151 of FIG. 2, a circular light shielding region 151A is provided at the center. Moreover, in order to support the light shielding area 151A, the light shielding area 151A and the ring-shaped outer peripheral part 151B are connected through linear connection parts 151C-151F. By arranging the center of the light blocking body 151 to coincide with the optical axis of the condensing lens 118, the light blocking body 151 is incident on the circular light blocking region 151A near the optical axis of the condensing lens 118 among the illumination light passing through the condensing lens 118. Light is blocked.

In the light shielding body 152 of FIG. 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 area 152A in the center. By arranging the center of the light shielding body 152 so as to coincide with the optical axis of the light converging lens 118, the light shielding region 152A of the substantially circular shape near the optical axis of the light condensing lens 118 among the illumination light passing through the light condensing lens 118 is provided. The incident light is blocked.

In addition, in the light shielding body 151 of FIG. 2, since the light incident on the connecting portions 151C to 151F is blocked, a deviation depending on the direction from the optical axis occurs in the brightness of the light passing through the light shielding body 151. The light passing through the housing 152 is almost uniform in brightness without such variation in brightness.

The light shield 153 of FIG. 4 and the light shield 154 of FIG. 5 are modified examples of the light shield 152 of FIG. 3. In the light shielding body 153 of FIG. 4, a plurality of circular openings having the same size are arranged at equal intervals in a ring shape so as to surround the central substantially circular light shielding area 153A. In the light shielding body 154 of FIG. 5, a plurality of circular openings are arranged at equal intervals in a ring shape so as to surround the central substantially circular light shielding area 154A, and the outer opening is larger than the inner 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.

Light shielding range of the light shield 119

Next, with reference to FIGS. 6-9, the light shielding range of the light shielding body 119 is examined.

FIG. 6 shows an example of an alignment mark 201 formed in the solar cell panel 102 as a mark for positioning. The alignment mark 201 crosses a line segment of width w (for example, 20 µm), length I (for example, 120 µm), and thickness t (for example, 2 µm) crosswise. It has a shape. The alignment mark 201 is formed by, for example, depositing an aluminum thin film on a glass substrate of the solar cell panel 102 or by removing a part of the thin film laminated in the manufacturing process of the solar cell panel 102. In addition, below, the case where the alignment mark 201 is formed mainly by vapor deposition is demonstrated.

In order to observe the alignment mark 201 of the line width w, according to Shannon's informational theorem, the observation optical system of the laser processing apparatus 101 may observe the uneven pattern of pitch p ≤ w / 2. You need to have the ability to do it. Such a condition will be briefly described with reference to FIG. 7.

When the pitch p of the diffraction grating 211 of FIG. 7 = w / 2 and the diffraction angle of the primary diffraction light of the diffraction grating 211 are α and the wavelength of the illumination light is λ, the following equation is established.

[expression]

sinα = λ / p = 2λ / w

Therefore, when the numerical aperture NA in the air of the objective lens 116 is sin beta, sin beta ≧ sin alpha = 2λ / w makes it possible to observe an uneven pattern of pitch p = w / 2. Also, the angle β is the maximum visual angle of the objective lens 116.

From the above equation, the first diffraction angle α of the diffraction grating 211 becomes larger as the pitch p becomes smaller, and becomes smaller as the pitch p becomes larger. Therefore, the light including the information of the fine (high spatial frequency) uneven pattern of the surface of the solar panel 102 is the peripheral region of the objective lens 116, that is, the angle with respect to the optical axis when viewed from the solar panel 102 ( Viewing angle) passes through a large area. On the other hand, the information of the roughness (low spatial frequency) surface of the solar panel 102 passes through the center region of the objective lens 116, that is, the region having a small viewing angle.

8 is a graph illustrating an example of an optical transfer function (OTF) of the objective lens 116. The horizontal axis represents spatial frequency (unit: cycle / mm) and the vertical axis represents optical transfer function (OTF). Further, the curve 221 represents an optical transfer function (OTF) curve of the entire objective lens 116, and the curve 222 represents a central region (hereinafter, referred to as a central region) of the objective lens 116 such that the viewing angle θ <α. (O), that is, the optical transfer function (OTF) curve for the region within the range of the numerical aperture less than sin α (= 2λ / w) of the objective lens 116 is shown. The optical transfer function (OTF) curve 222 has a narrower frequency band than the optical transfer function (OTF) curve 221, and specifically, ranges from 0 to 1 / p (= 2 / w). Becomes

Further, the optical transfer function (OTF) curve in the case where the central region α of the objective lens 116 is shielded from light, that is, the optical transfer function (OTF) of the peripheral region of the objective lens 116 such that the viewing angle θ≥α. The curve is obtained by subtracting the curve 222 from the curve 221, and specifically, the curve 231 shown in FIG. 9. This optical transfer function (OTF) curve 231 has the characteristic that the spatial frequency peaks at 1 / p (= 2 / w).

Therefore, by shielding the central region α of the objective lens 116, the uneven pattern having a spatial frequency of less than 2 / w is attenuated, and the uneven pattern having the same pitch as the line width w of the alignment mark 201 is emphasized. Can be observed. As a result, the alignment mark 201 of the line width w can be emphasized and observed.

Therefore, in the laser processing apparatus 101, a part of illumination light is interrupted by the light shielding body 119 so that illumination light may not inject into the center area | region (alpha) of the objective lens 116. FIG. That is, the illumination light transmitted through the condenser lens 118 is blocked by the light blocking member 119 in the vicinity of the optical axis, and formed in the pupil of the objective lens 116, and then the center region α of the objective lens 116. The solar cell panel 102 is irradiated to the outer region. Therefore, compared with the case where a part of illumination light is not interrupted by the light shielding body 119, the low frequency component whose spatial frequency is less than 2 / w among the uneven | corrugated pattern of the observation surface (= processing surface) of the solar panel 102. This is weakly excited, and high frequency components with spatial frequencies of 2 / w or more are excited with almost the same intensity. As a result, the optical transfer function (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.

Effects of the laser processing apparatus 101

10-14, the effect of the laser processing apparatus 101 is demonstrated in more detail.

As shown in FIG. 10, the illumination light emitted from the objective lens 116 is collected as a wave surface substantially parallel to the observation surface of the solar panel 102, and the reflected light reflected from the observation surface is reflected in the objective lens. Return to (116).

11 and 12 are enlarged views of the range 251 near the condensing point surrounded by the dotted lines in FIG. 10. In addition, FIG. 11 is a diagram schematically showing a state in which illumination light is incident on the solar panel 102 during fabrication, and FIG. 12 is a diagram schematically illustrating a state in which illumination light is reflected at the solar panel 102 during fabrication. It is shown.

In the example of FIGS. 11 and 12, solar panel 102 is comprised by three layers of layer 102A, layer 102B and layer 102C from below, and layer 102B and layer 102C. The power generation region is formed by this. The layer 102B has a higher reflectance than the layer 102C, and the shade pattern is formed by the region where the layer 102C is formed and the region where the layer 102C is not formed and the layer 102B appears on the surface. 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.

Moreover, in the area | region where the layer 102B and the layer 102C of the right end part in the figure are not formed, the alignment mark 201 is formed in the upper surface of layer 102A. 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.

Illumination light incident on the wavefront parallel to the observation surface of the solar panel 102 is modulated on the observation surface of the solar panel 102 to become reflected light. Among the reflected lights, light information is superimposed on light reflected on the light pattern formed by the layer 102B and the layer 102C. Since the level difference L1 is less than the wavelength?, The reflected light having the light and shade information superimposed thereon changes only the amplitude of the incident angle with little change in the incident angle as shown in the range 261 surrounded by the dotted line in FIG. In addition, in the said figure, the change of amplitude is shown by the thickness of a line. On the other hand, in the reflected light, the light reflected near the alignment mark 201 overlaps the uneven information in addition to the shade information. Since the level difference L2 is larger than the wavelength λ, the reflected light having the uneven information overlaps in amplitude as shown in the range 262 surrounded by the dotted line in FIG. 12, and the reflection angle changes with respect to the incident angle.

Taking this into consideration from the near field near the focusing point to the far field near the objective lens 116, as shown in Fig. 13, when the incident angle of the illumination light A1 is θi and the reflection angle of the reflected light B1 is θo, When only the shade information is superimposed on the observation surface of the solar panel 102 and the unevenness information does not overlap, the incident angle θ i = the reflection angle θ o. On the other hand, when the uneven information overlaps on the observation surface of the solar panel 102, the incident angle θ i ≠ the reflection angle θ o.

In the conventional dark field optical system, the reflected light in which only the shaded information at which the incidence angle θi = the reflection angle θo is superimposed passes through the outside of the objective lens or is blocked in the middle and is not observed. On the other hand, a part of the reflected light in which the uneven information at which the incident angle θi ≠ the reflection angle o overlaps is incident on the objective lens and is observed without being blocked in the middle. Therefore, by using the conventional dark field optical system, the uneven pattern of the observation surface of the solar panel 102 can be observed at a high SNR, and the alignment mark 201 can be observed at a high SNR as a matter of course. On the other hand, the shade pattern of the observation surface of the solar cell panel 102 cannot be observed.

In addition, in the conventional bright field optical system, a part of the reflected light in which only the shade information is superimposed and the reflected light in which the uneven information is superimposed is observed by being incident on the objective lens. Therefore, when the conventional bright field optical system is used, both the light and dark patterns of the observation surface of the solar panel 102 can be observed. On the other hand, the SNR of the concave-convex pattern of the observation surface of the solar cell panel 102 is lowered, and the alignment mark 201 cannot be observed at a high SNR as compared with the dark field optical system.

On the other hand, in the laser processing apparatus 101, irrespective of whether or not the reflection angle o is different from the incident angle i, the reflected light is incident on the objective lens 116 and observed when it is within the range of? have. For example, in the example of FIG. 14, both of the reflected light B11 having the same reflected angle θo and the reflected light B12 having the different reflected angle o with respect to the incident light A11 are incident on the objective lens 116 and observed. Can be. Therefore, both the light and shade patterns of the observation surface of the solar cell panel 102 can be observed.

In addition, since light such as reflected light B13 in which the reflection angle θo> β in FIG. 14 is not incident on the objective lens 116, it cannot be observed similarly to the conventional darkfield optical system and brightfield optical system.

Further, since no illumination light is incident on the central region α indicated by the diagonal lines in FIG. 14, the reflected light having the reflection angle θo ≦ α is substantially reduced. Therefore, a component lower than the spatial frequency corresponding to the line width w of the alignment mark 201 can be attenuated among the uneven patterns of the observation surface of the solar cell panel 102. Therefore, the alignment mark 201 can be emphasized and observed with high SNR.

For example, when the alignment mark 201 is formed by removing a part of the thin film of the solar cell panel 102, the shade pattern by laser processing may be formed in the alignment mark 201. In the laser processing apparatus 101, the shade pattern in the alignment mark 201 can also be observed, and as a result, the alignment mark 201 can be observed more clearly.

As mentioned above, in the laser processing apparatus 101, both the alignment mark 201 of the solar cell panel 102 and a shade pattern can be observed favorably. In addition, by observing the alignment mark 201 satisfactorily, the positioning accuracy of the solar cell panel 102 is improved, and the time required for positioning can be shortened. As a result, the processing accuracy of the solar cell panel 102 can be improved and the processing time can be shortened.

2. Variations

In addition, in the above description, the example in which the light shielding body 119 is provided between the condenser lens 118 and the half mirror 120 has been shown, but more precisely between the half mirror 120 and the objective lens 116. For example, a light shield may be provided between the half mirror 120 and the dichroic mirror 115 so as to block the illumination light incident on the central region α of the objective lens 116. As a result, the optical transfer function (OTF) characteristic of the objective lens 116 becomes substantially the same as that shown in FIG. As a result, similarly to the above-described embodiment, both the light and dark patterns of the solar cell panel 102 can be observed, and the alignment mark 201 can be emphasized and observed.

In this case, not only the illumination light incident on the central region α, but also the light passing near the optical axis of the objective lens 116 among the reflected light from the solar cell panel 102 can be blocked. Therefore, more components lower than the spatial frequency corresponding to the line width w of the alignment mark 201 can be blocked among the uneven patterns of the observation surface of the solar cell panel 102, and the alignment mark 201 is emphasized and observed. It becomes possible.

In addition, although the example which provided the circular light source in the illuminating device 117 was shown in the above-mentioned description, you may make it install the light source of a different shape. For example, as shown in FIG. 15, you may provide the light source which emits illumination light of rectangular cross section. In this case, however, it is preferable that the shape of the light shielding area of the light shielding body be rectangular instead of circular, as described below.

FIG. 16 shows an example of the shape of the cross section after the illumination light having the cross section shown in FIG. 15 passes through the condensing lens 118. The cross section of the illumination light after passing through the condensing lens 118 has a slightly rounded corner compared with the cross section of the illumination light in the illumination device 117.

FIG. 17 illustrates an example of an area to be shielded and an area not to be shielded in the case where the illumination light shown in FIG. 16 is shielded using a shielding body having a substantially circular shielding area as described with reference to FIGS. 2 to 5. It is shown. In addition, the area | region shown by the mesh shape in the figure shows the light shielding area | region. As shown in the figure, in the case where the light having a substantially rectangular cross section is shielded by a circular light shielding area, a deviation occurs depending on the position of the brightness of the illumination light after passing through the light shield. That is, closer to four corners of the cross section of the illumination light increases the illumination light passing through the light shielding body, while the illumination light passing through the light shielding body decreases away from the four corners. Thus, 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, nonuniformity arises in the brightness of the illumination light irradiated to the solar cell panel 102.

Therefore, as shown in FIG. 18, it is preferable to shield the rectangular area of the center of illumination light according to the cross section of illumination light.

19 and 20 are diagrams illustrating an example of a light shielding body that shields a rectangular area in the center of illumination light. In the light shielding body 301 of FIG. 19, a rectangular light shielding region 301A is provided at the center. In addition, in order to support the light shielding area 301A, the edge part of the light shielding area 301A and the ring-shaped outer peripheral part 301B are connected by linear support members 301C-301F. In the light shielding body 311 of FIG. 20, similar to the light shielding body 301, a rectangular light shielding region 311A is provided at the center. Moreover, in order to support the light shielding area 311A, the center part of each side of the light shielding area 311A, and the ring-shaped outer peripheral part 311B are connected by the linear support members 311C-311F.

By arranging the center of the light shield 301 or the light shield 311 so as to coincide with the optical axis of the condenser lens 118, rectangular light shielding near the optical axis of the condenser lens 118 among the illumination light passing through the condenser lens 118. Light incident on the region 301A or the light shielding region 311A is blocked.

As described above, the shape of the light shielding area of the light shielding body is preferably made to be substantially the same as the shape of the cross section of the illumination light.

In addition, in the above-mentioned description, although the example which comprises the light shielding body 119 by the metal plate was shown, you may make it use the light shielding body which formed the light shielding area by the light shielding film etc. in transparent members, such as glass, for example. In addition, a light shielding film may be formed directly on the objective lens 116 or the condenser lens 118.

In addition, in the previous description, although the example which applies this invention to the laser processing apparatus 101 was shown, this invention can be applied to the whole apparatus which performs positioning of an object based on the alignment mark. In addition, the object used as the object of observation of the present invention is not limited to the solar cell panel 102, but it is possible to use various substrates or the like on which alignment marks are provided.

In addition, although the above-mentioned description showed the example which uses LED for the light source of the illuminating device 117, it is also possible to use another kind of light source.

In addition, although the above-mentioned description showed the example which makes illumination light monochromatic light, you may make it use the illumination light which has a predetermined wavelength width. In this case, a representative wavelength of the illumination light, for example, a peak wavelength, a center wavelength, a maximum wavelength, or the like may be used for the wavelength λ of the illumination light used in the above equation or the like. For example, when white light is used as illumination light, it is considered to use the central green wavelength (546.1 nm).

In addition, it becomes possible to observe the alignment mark more clearly by using illumination light as monochromatic light. On the other hand, when illumination light is made into white light, not only the light and shade pattern of an object, but also the color of an object can be observed.

In addition, in the above description, although the example which makes the shape of the alignment mark cross shape was shown, it is not limited to such an example, Any shape can be employ | adopted. In addition, when the shape of an alignment mark is made into shapes other than a cross shape, the width of the narrowest part of an alignment mark is used for the width w used for the said formula etc., for example.

In addition, in the above description, by changing the direction of the illumination light by the half mirror 120, the optical path of the illumination light from the illumination device 117 to the half mirror 120 and from the half mirror 120 to the CCD camera 122. Although the example of splitting the optical paths of the reflected light is shown, the two optical paths may be split by changing the direction of the reflected light or changing both the illumination light and the reflected light.

In addition, the laser oscillator 111, the illumination device 117, and the CCD camera 122 may be attached to the outside of the laser processing apparatus 101 separately from the laser processing apparatus 101.

In addition, embodiment of this invention is not limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the scope of this invention.

101: Laser processing apparatus 102: Solar panel
111: laser oscillator 112: beam expander
113: slit 114: imaging lens
115: dichroic mirror 116: objective lens
117 ： Lighting device 118 ： Condensing lens
119: Shading body 120: Half mirror
121: Imaging lens 122: CCD camera
151-154: Light shielding bodies 151A-154A: Light shielding area
201: Alignment mark 301: Shading body
301A: Shading area

Claims (5)

In the observation optical system for observing the mark for positioning the object,
An objective lens;
A condenser lens for forming illumination light emitted from the light source in the pupil of the objective lens;
An imaging lens for forming reflected light after passing through the objective lens as reflected light from the object to which the illumination light is irradiated through the objective lens;
Branching means for splitting the optical path between the illumination light and the reflected light between the condensing lens and the objective lens and between the objective lens and the imaging lens; And
When the wavelength of the illumination light is λ and the width of the narrowest part of the positioning mark is w, it is provided between the condensing lens and the branching means and has a numerical aperture of less than 2λ / w of the objective lens. Light blocking means for blocking the illumination light incident within a range of; and light shielding means provided between the branching means and the objective lens and blocking the reflected light incident within a range of a numerical aperture of less than 2λ / w of the objective lens. At least one side is provided, The observation optical system characterized by the above-mentioned. The method according to claim 1,
The light shielding means has a light shielding area having the same shape as a cross section of the illumination light. The method according to claim 1,
The illumination system of the illumination light, characterized in that the monochromatic light. In the laser processing apparatus provided with the observation optical system for observing the mark for positioning an object, and the processing optical system for irradiating the laser beam for a process to the said object,
The observation optical system includes:
A light source emitting illumination light;
An objective lens;
A condenser lens for forming the illumination light at the pupil of the objective lens;
An imaging lens for forming reflected light after passing through the objective lens as reflected light from the object to which the illumination light is irradiated through the objective lens;
Branching means for splitting the optical path between the illumination light and the reflected light between the condensing lens and the objective lens and between the objective lens and the imaging lens; And
When the wavelength of the illumination light is λ and the width of the narrowest part of the positioning mark is w, it is provided between the condensing lens and the branching means and has a numerical aperture of less than 2λ / w of the objective lens. Light blocking means for blocking the illumination light incident in the range of; and light shielding means provided between the branching means and the objective lens and blocking the reflected light incident within a range of a numerical aperture of less than 2λ / w of the objective lens. At least one of them is provided, The laser processing apparatus characterized by the above-mentioned. 5. The method of claim 4,
And the laser beam is irradiated to the object through the objective lens.

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