JP2008264869A - Laser beam working apparatus, positioning device, observing device, and method for observing opaque part on transparent substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an observing method and an observing device capable of clearly identifying an opaque device pattern formed on a transparent substrate in an observation image. <P>SOLUTION: An adhesive sheet 4 is affixed to a side with a device pattern 3 being formed thereon, and fixed to a transparent stage 7. The coaxially transmitted illumination light L1 and the obliquely transmitted illumination light L2 are superposingly irradiated from an upper side of the stage 7, and the observation is performed by a back side observation means 6 from a lower side of the stage 7 via the stage 7. In the observation image, a dark (black) device pattern image is observed corresponding to the device pattern 3 in the observation image, and a part other than the device pattern image IP1 is observed bright. Further, the part IB1 corresponding to bubbles 5 is also observed sufficiently bright. Thus, the shape of the device pattern 3 can be clearly specified in the observation image. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique capable of clearly identifying a device pattern provided on a transparent or translucent substrate in an observation image.

  For splitting by irradiating a pulse laser to a device pattern such as short wavelength LD (laser diode) or LED (light emitting diode) formed using a hard and brittle material such as sapphire for the substrate A method for forming the starting point is known (for example, see Patent Document 1).

  When the division starting point for dividing the substrate into device chips is formed by the device disclosed in Patent Document 1 or other devices, the division position is determined by using a CCD camera as a predetermined position reference object provided on the substrate. The position is determined by arithmetic processing based on the coordinates of the position reference object specified based on the obtained imaging data. As the position reference object, a positioning marker formed in advance is used, and the device pattern itself may also serve as the position reference object.

  The determination accuracy of the division position depends on the state of the image of the position reference object obtained by the observation optical system. Therefore, when observing and imaging with the observation optical system, it is required that an image of the position reference object is clearly obtained and that the position reference object is clearly distinguished from a foreign substance attached to the substrate or the substrate. For this reason, observation by the observation optical system is often performed while irradiating the observation surface with illumination light from coaxial illumination (bright field illumination) or oblique illumination (dark field illumination).

International Publication No. 2006/062017

  For example, when trying to divide a transparent or translucent substrate such as sapphire (hereinafter referred to as “transparent substrate”) at a predetermined position, it is necessary to accurately specify an arbitrary position on the transparent substrate. It may become. In such a case, it is common to specify the position by using the position and shape of the opaque portion formed on the transparent substrate as a clue. For example, when an opaque device pattern such as a metal thin film is to be divided into individual device units, a predetermined adhesive sheet is attached to the main surface on which the device pattern is formed, and a transparent substrate The main surface on the side on which the device pattern is not formed (the adhesive sheet is not attached) may be fixed so as to face the side on which the processing means, the observation optical system, and the like are provided. In this case, the device pattern is observed from the back side through the transparent substrate from the observation optical system.

  In such a case, when there are bubbles generated due to insufficient adhesion of the pressure-sensitive adhesive sheet at the interface portion between the pressure-sensitive adhesive sheet and the transparent substrate, the end portion of the device pattern, and the like, Due to the irregular reflection from the bubbles, it becomes difficult to distinguish the bubbles from the device pattern, and the shape of the device pattern may not be accurately specified based on the observation image (captured image).

  In addition, when a diffusion layer having an action of diffusing illumination light for observation is provided between the device pattern and the transparent substrate, that is, a diffusion layer is formed as a base layer on the transparent substrate. Even when a device pattern is provided on the diffusion layer, the observation optical system observes the device pattern with not only the transparent substrate but also the diffusion layer interposed, so that an accurate image can be obtained. There may not be. The diffusion layer corresponds to a layer formed by embossing the surface of the transparent substrate for the purpose of increasing the light extraction efficiency in the optical device.

  FIG. 9 is a diagram for explaining an observation image obtained in such a case. In this case, as shown in FIG. 9A, a layered structure is formed by forming a device pattern 103 after a diffusion layer 102 is provided as an underlayer on one main surface of a transparent substrate 101. A case where the adhesive sheet 104 is attached to the main surface of the body 100 on which the device pattern 103 is formed, the adhesive sheet 104 side is sucked and fixed to the stage 107, and observation is performed by the observation means 106. It is shown as an example. It is assumed that bubbles 105 are present at the interface between the pressure-sensitive adhesive sheet 104 and the transparent substrate 101 and the end portion of the device pattern 103.

  As shown in FIG. 9A, when observation is performed by the observation unit 106 in a state where the incident illumination light L1001 is irradiated toward the transparent substrate 101, the illumination light is absorbed and reflected by the diffusion layer 102. Therefore, as shown in FIG. 5B, the entire observation image I1001 is a bright image, and the influence of bubbles is offset, but the device pattern image IP1001 becomes unclear.

  As a method for solving such a problem, a transmission illumination system in which a stage is made of transparent quartz and coaxial illumination (transmission illumination) is applied to a substrate attached to an adhesive sheet through the stage from below the stage. A mode in which the device pattern is observed using the imagination can be considered.

  FIG. 10 is a diagram for explaining an observation image obtained in such a case. As shown in FIG. 10A, the observation means 106 is irradiated with the transmitted illumination light L1002 from the space on the opposite side of the quartz transparent stage 207 with respect to the observation means 106. When the observation is performed, the portion of the device pattern 103 does not transmit illumination, but transmits through the other portions. Therefore, the observation unit 106 observes an image of the transmitted light L1002t. More specifically, as shown in FIG. 10B, the observation image I1002 is a relatively bright image as a whole although it receives light attenuation due to absorption and diffusion (diffuse reflection) by the adhesive sheet 104 and the diffusion layer 102. As obtained. However, a dark (black) device pattern image IP1002 is observed for a portion of the device pattern 103 through which illumination light does not pass. Therefore, the device pattern 103 itself is observed so as to be distinguishable with high contrast with respect to the transparent substrate 101. However, if the bubble 105 exists, the illumination light is refracted there, and therefore the image IB1002 corresponding to the bubble 105 is observed darker than the surroundings. When the amount of irradiation light is increased to brighten the bubble portion, the device pattern 103 may also be transmitted and the contrast may be lowered. Therefore, there remains a problem that it is difficult to clearly identify the bubble 105 and the device pattern 103 in the observation image I1002.

  In addition, in the case of such transmitted illumination, the contrast (the clarity of the image of the device pattern to be observed and imaged) is observed when the device pattern is observed due to the variation in transmittance between the lots of substrates. Depending on the individual transparent substrate, there may be a problem that the accuracy of determining the division position is not constant.

  The present invention has been made in view of the above problems, and an observation method capable of clearly identifying an opaque device pattern formed on a transparent substrate in an observation image, and processing using such an observation method It is an object of the present invention to provide an observation apparatus capable of accurately specifying a position and a laser processing apparatus as an application thereof.

  In order to solve the above problems, the invention of claim 1 is a laser processing apparatus including an observation device for observing an opaque portion formed on one main surface side of a transparent substrate which is a workpiece. The observation apparatus includes: a supporting unit that supports the transparent substrate; a coaxial illumination light source that emits coaxial illumination light; an oblique illumination light source that emits oblique illumination light; and a first main surface of the transparent substrate. Observation means for observing the transparent substrate from the side, the support means supports the transparent substrate so that the observation means can observe, and the coaxial illumination light source and the oblique light source are provided on the transparent substrate. The coaxial illumination light and the oblique illumination light are respectively applied to the transparent substrate from the second principal surface side which is the principal surface opposite to the first principal surface.

  The invention of claim 2 is the laser processing apparatus according to the invention of claim 1, wherein the transparent substrate is irradiated with the coaxial illumination light and the oblique illumination light superimposed on the transparent substrate. The observation unit acquires an observation image of the transparent substrate.

  Further, the invention of claim 3 is the laser processing apparatus according to the invention of claim 2, wherein the first observation image observed by the imaging means when the transparent illumination substrate is irradiated with the coaxial illumination light; The image forming apparatus further includes a combining unit that obtains a combined image with the second observation image observed by the imaging unit when the oblique illumination light is irradiated onto the transparent substrate.

  According to a fourth aspect of the present invention, there is provided a positioning device including an observation device for observing an opaque portion formed on one main surface side of a transparent substrate, the observation device comprising the transparent substrate. Support means for supporting, coaxial illumination light source for irradiating coaxial illumination light, oblique illumination light source for irradiating oblique illumination light, and observation means for observing the transparent substrate from the first principal surface side of the transparent substrate The support means supports the transparent substrate so that the observation means can observe, and the coaxial illumination light source and the oblique light source are main surfaces opposite to the first main surface of the transparent substrate. The coaxial illumination light and the oblique illumination light are respectively applied to the transparent substrate from the second main surface side.

  The invention of claim 5 is the positioning device according to the invention of claim 4, wherein the transparent substrate is irradiated with the coaxial illumination light and the oblique illumination light in a superimposed manner. The observation means acquires an observation image of the transparent substrate.

  The invention of claim 6 is the positioning device according to the invention of claim 4, wherein the first observation image observed by the imaging means when the coaxial substrate is irradiated with the coaxial illumination light; and The image forming apparatus further includes a combining unit that obtains a combined image with the second observation image observed by the imaging unit when the oblique illumination light is irradiated onto the transparent substrate.

  The invention according to claim 7 is an observation device for observing an opaque portion formed on one main surface side of the transparent substrate, the supporting means for supporting the transparent substrate, and coaxial illumination light. A coaxial illumination light source for irradiating, an oblique illumination light source for irradiating oblique illumination light, and an observation means for observing the transparent substrate from the first main surface side of the transparent substrate, the support means, The observation means supports the transparent substrate so that observation is possible, and the coaxial illumination light source and the oblique light source are from a second main surface side which is a main surface opposite to the first main surface of the transparent substrate. The coaxial substrate is irradiated with the coaxial illumination light and the oblique illumination light, respectively.

  The invention according to claim 8 is the observation apparatus according to the invention according to claim 7, wherein the transparent substrate is irradiated with the coaxial illumination light and the oblique illumination light in a superimposed manner. The observation means acquires an observation image of the transparent substrate.

  The invention of claim 9 is the observation apparatus according to the invention of claim 7, wherein the first observation image observed by the imaging means when the coaxial substrate is irradiated with the coaxial illumination light; and The image processing apparatus further includes a combining unit that obtains a combined image by arithmetic combining with the second observation image observed by the imaging unit when the oblique illumination light is irradiated onto the transparent substrate.

  The invention according to claim 10 is the observation device according to any one of claims 7 to 9, wherein the irradiation state of at least one of the coaxial illumination light and the oblique illumination light on the transparent substrate. By adjusting the light amount, the amount of light in the observation region grasped by the observation means can be adjusted.

  The invention according to claim 11 is the observation apparatus according to the invention of claim 10, wherein the distance from the opaque substrate can be adjusted for at least one of the coaxial illumination light source and the oblique illumination light source. It is characterized by comprising.

  The invention according to claim 12 is the observation apparatus according to the invention according to claim 10, wherein the brightness of at least one of the coaxial illumination light source and the oblique illumination light source is adjustable. It is characterized by.

  The invention of claim 13 is the observation apparatus according to the invention of claim 10, characterized in that the irradiation angle of the oblique illumination light to the opaque substrate is adjustable. To do.

  The invention according to claim 14 is the observation apparatus according to any one of claims 7 to 13, wherein the support means is a transparent stage, and the observation means is transparent through the stage. Observing the conductive substrate.

  The invention of claim 15 is the observation apparatus according to any one of claims 7 to 14, wherein the coaxial illumination light and the oblique illumination light are supported by the support means. The transparent substrate is irradiated from above the substrate, and the observation means observes the transparent substrate from below the transparent substrate.

  The invention of claim 16 is a method of observing an opaque portion formed on one main surface side of a transparent substrate, wherein the transparent substrate is supported by a predetermined support means. Observing the transparent substrate from the other side of the transparent substrate with a predetermined observation means while irradiating coaxial illumination light and oblique illumination light superimposed on the transparent substrate from one side of the transparent substrate. It is characterized by that.

  The invention of claim 17 is the observation method according to the invention of claim 16, wherein the amount of light other than the opaque portion of the transparent substrate in the observation region grasped by the observation means is in the observation region. The irradiation state of at least one of the coaxial illumination light and the oblique illumination light is adjusted so as to be substantially the same as a whole.

  The invention according to claim 18 is the observation method according to the invention according to claim 17, wherein at least one of the coaxial illumination light source for irradiating the coaxial illumination light, the oblique illumination light source for irradiating the oblique illumination light, and the transparency. The irradiation state is adjusted by adjusting the distance to the substrate.

  The invention according to claim 19 is the observation method according to the invention according to claim 17, wherein at least a luminance of the coaxial illumination light source that irradiates the coaxial illumination light and a luminance of the oblique illumination light source that irradiates the oblique illumination light. The irradiation state is adjusted by adjusting one side.

  The invention of claim 20 is the observation method according to the invention of claim 17, characterized in that the irradiation state is adjusted by adjusting an irradiation angle of the oblique illumination light to the opaque substrate. To do.

  The invention according to claim 21 is the observation method according to any one of claims 16 to 20, wherein the support means is a transparent stage, and the other side faces the stage. A transparent substrate is fixed to the stage to support the transparent substrate, and the observation means observes the transparent substrate through the stage.

  The invention according to claim 22 is the observation method according to any one of claims 16 to 21, wherein the coaxial illumination light and the oblique illumination light are supported by the support means. The transparent substrate is irradiated from above the substrate, and the observation means observes the transparent substrate from below the transparent substrate.

  The invention of claim 23 is a method of observing an opaque portion formed on one main surface side of a transparent substrate, wherein the transparent substrate is supported by a predetermined support means (a (B) imaging a first observation image by a predetermined imaging means from the other side of the transparent substrate while irradiating coaxial illumination light from one side of the transparent substrate toward the transparent substrate; Imaging a second observation image by a predetermined imaging means from the other side of the transparent substrate while irradiating oblique illumination light from one side of the transparent substrate toward the transparent substrate; and (c) the step And a step of creating a composite image of the first observation image and the second observation image.

  According to the invention of claim 1 to claim 23, when an opaque part such as a device pattern is formed on a transparent substrate, the shape of the opaque part such as the device pattern is clearly specified in the observation image. Is possible.

  In particular, according to the first to third aspects of the invention, when a transparent substrate having an opaque portion is a workpiece, the shape of the opaque portion on the transparent substrate can be clearly specified. Therefore, highly accurate laser processing can be performed.

  In particular, according to the inventions of claims 4 to 7, when positioning a transparent substrate having an opaque portion, the shape of the opaque portion on the transparent substrate can be clearly specified. Positioning with high accuracy can be performed.

  In particular, according to the inventions of claims 5 to 13 and claims 17 to 20, the observation can be performed after suitably adjusting the light amounts of the coaxial illumination light and the oblique illumination light, so that the transparent portion and the opaque portion are opaque. Good observation results with improved contrast with the part can be obtained.

  In particular, according to the inventions of claims 14 and 21, it is possible to clearly identify the shape of the opaque portion in a state where the transparent substrate is stably held.

<1. First Embodiment>
<1.1. Principle configuration for observation>
FIG. 1 is a diagram for explaining an observation method according to the first embodiment of the present invention. In the present embodiment, the observation target is a diffusion layer 2 having an action of diffusing illumination light for observation on one main surface side of a transparent substrate 1 such as sapphire as shown in FIG. Will be described as an example of a laminated body 10 in which an opaque device pattern 3 such as a metal wiring or an electrode is formed. An embodiment in which a transparent semiconductor layer made of a group III nitride such as GaN or the like is provided between the transparent substrate 1 and the device pattern 3 may be used.

  Moreover, in this Embodiment, as shown to Fig.1 (a), after sticking the adhesive sheet 4 to the main surface at the side in which the device pattern 3 of the laminated body 10 was formed, The case where the device pattern 3 is observed with the side fixed to a transparent stage 7 made of, for example, quartz will be described as an example. It is assumed that bubbles 5 are present at the interface between the pressure-sensitive adhesive sheet 4 and the transparent substrate 1 and at the end portion of the device pattern 3. The observation method according to the present embodiment is more effective when observing the laminated body 10 fixed in such a manner.

  Such fixation can be realized by a known method. For example, when suction fixing is performed, a plurality of suction grooves are provided concentrically on the upper surface of the stage 7, and suction holes are provided radially at the bottom of the suction groove so that the workpiece is placed on the upper surface of the stage 7. In this state, the suction means such as a suction pump connected to the suction hole is operated to apply a suction force to the workpiece along the suction groove.

  In the present embodiment, the incident angle is 90 ° from above the stage 7, that is, from the back side of the transparent substrate 1 with respect to such a laminate 10 (substantially perpendicular to the main surface of the substrate). Coaxial illumination light (bright field illumination light) L1 having an optical axis and oblique illumination light (dark field illumination light) L2 having an acute incident angle are simultaneously irradiated, and are composed of, for example, a CCD camera or a predetermined display device. The back surface observation means 6 is provided below the stage 7 so that the device pattern 3 is observed through the stage 7. That is, observation is performed by the back surface observation means 6 while superimposing the coaxial illumination light L1 and the oblique illumination light L2 as transmitted illumination light. Correspondingly, in the following description, the coaxial illumination light L1 and the oblique illumination light L2 are also referred to as coaxial transmission illumination light L1 and oblique light transmission illumination light L2, respectively.

  As the light source of the coaxial illumination light L1 and the oblique illumination light L2, for example, a high-intensity white LED having strong directivity (irradiation angle of about 15 °) is suitable. In addition, a light emitting end face of a lamp or an optical fiber can be used.

  FIG. 1B is a diagram illustrating an observation image I1 obtained by the back surface observation means 6 in this case. In this case, neither the coaxial transmission illumination light L1 nor the oblique transmission illumination light L2 is transmitted through the device pattern 3 portion. Therefore, in the observation image I1, a dark (black) device pattern image IP1 corresponding to the device pattern 3 is observed. On the other hand, transmitted light L1t is obtained in portions other than the device pattern 3. In this transmitted light L1t, a component in which the coaxial transmitted illumination light L1 is directly transmitted and a component in which the oblique transmitted light L2 is diffused (diffuse reflection) by the adhesive sheet 4 and the diffusion layer 2 are transmitted as a result. It will be. As a result, in the observation image I1, the part other than the device pattern image IP1 is observed brightly. In the bubble 5, both the coaxial transmission illumination light L1 and the oblique transmission illumination light L2 are refracted. However, since the oblique transmission illumination light L2 diffuses as described above, a portion corresponding to the bubble 5 in the observation image I1. IB1 is also observed sufficiently brightly. Even when bubbles 5 or the like are present, variation in the amount of light in the observation image I1 other than the opaque portion where the device pattern 3 is formed is suppressed by irradiating the oblique light transmission illumination L2. It means that. As a result, in the observation image I1, the black device pattern image IP1 is clearly identified with sufficient contrast from other portions.

  That is, for the laminate 10 in which the device pattern 3 is formed on the transparent substrate 1, the adhesive sheet 4 is attached to the side on which the device pattern 3 is formed, and then fixed to the transparent stage 7. In the observation image, the coaxial transmission illumination light L1 and the oblique transmission illumination light L2 are superimposedly irradiated from above the stage 7 and observed by the back surface observation means 6 from the lower side of the stage 7 through the stage 7. The shape of the device pattern 3 can be clearly specified. Further, not only in the device pattern but also in the case where a similar opaque portion is formed, the shape of the opaque portion can be clearly identified by applying the above-described method. In addition, since it is not essential for observation to have the adhesive sheet 4, it is possible in principle to place the transparent substrate 1 directly on the stage 7 for observation. In such a case, it is possible to observe without being affected by irregular reflection by the pressure-sensitive adhesive sheet 4.

  FIG. 2 is a diagram showing in more detail the mode of irradiation of the coaxial transmitted illumination light L1 from the coaxial illumination light source S1 and the irradiation of the oblique transmitted light L2 from the oblique illumination light source S2. Specifically, coaxial transparent illumination light L1 emitted from the coaxial illumination light source S1 and oblique light transmission illumination light L2 emitted from the oblique illumination light source S2 are applied to the transparent substrate 1 from above the stage 7. It has become.

  However, in order to more suitably obtain the effect of improving the contrast of the opaque portion by irradiating the obliquely transmitted illumination light L2 as described above, the light amount of the observation region other than the opaque portion of the transparent substrate 1 is The irradiation state of at least one of the coaxial transmission illumination light L1 and the oblique transmission illumination light L2 is adjusted so that the entire observation area is substantially the same (at least when viewed with the naked eye). Preferably it is made possible. For example, in the case of FIG. 1, depending on the irradiation balance between the coaxial transmission illumination light L1 and the oblique transmission illumination light L2, the portion IB1 corresponding to the bubble 5 in the observation image I1 can be obtained directly from the transmission light L1. It may be observed with a different contrast. In such a case, if the irradiation state can be adjusted so that the contrast between the two becomes approximately the same, the opaque portion can be more reliably identified.

  As one of the measures, by adjusting the distance between the transparent substrate 1 and at least one of the coaxial illumination light source S1 that irradiates the coaxial transmitted illumination light L1 and the oblique illumination light source S1 that irradiates the oblique illumination light L2, the observation region is adjusted. There exists an aspect which makes the light quantity other than the whole opaque part substantially the same. FIG. 2 illustrates a case where the coaxial illumination light source S1 is further away from the transparent substrate 1 than the oblique illumination light source S2.

  Alternatively, an aspect in which at least one of the coaxial illumination light source S1 and the oblique illumination light source S2 adjusts the luminance so that the light amounts other than the opaque portion in the entire observation region are made substantially the same may be used. Alternatively, as shown in FIG. 2, a diffusion plate D may be provided between the coaxial illumination light source S1 and the irradiation position.

  Furthermore, the aspect which makes the light quantity other than the opaque part of the whole observation area | region substantially the same may be adjusted by adjusting the incident angle (theta) of the oblique transmission illumination light L2.

  These adjustment methods may be appropriately selected according to the observation target, or may be used in a superimposed manner.

  In addition, when the observation means is an image pickup device such as a CCD camera, for example, the amount of light for the observation region can be grasped by digitizing in units of pixels, so that the optimum irradiation state (light source (Optimum conditions such as position, brightness, angle, etc.) may be determined.

  FIG. 2 illustrates the case where two oblique illumination light sources S2 are provided bilaterally symmetrically with the irradiation direction of the coaxial transmitted illumination light L1 as an axis of symmetry. However, the number of oblique illumination light sources S2 is shown here. There is no limitation, and a mode in which a larger number of oblique illumination light sources S2 are arranged so that the irradiation direction of the coaxial transmission illumination light L1 is an axis of symmetry may be employed.

<1.2. Application to laser processing equipment>
Next, a laser processing apparatus as an example of an observation apparatus capable of performing observation based on the above-described principle will be described. FIG. 3 is a schematic diagram schematically showing the configuration of the laser processing apparatus 50. In addition, in FIG. 3, although the case where the to-be-processed object (observation object) is the laminated body 10 affixed on the adhesive sheet 4 is illustrated, a to-be-processed object is restricted to this is not. In addition, the operations of the following parts of the laser processing apparatus 50 (laser light irradiation, stage movement, illumination light irradiation, arithmetic processing for determining a processing position, etc.) are all performed by a predetermined computer or the like (not shown). It shall be controlled by the control means.

  The laser processing apparatus 50 mainly includes a front surface observation unit 50A, a back surface observation unit 50B, and a transparent stage 7 made of, for example, quartz that can move between the two. The front surface observation unit 50A is an observation unit that observes the workpiece placed on the stage 7 from the side irradiated with laser light (this is referred to as the front surface), and the back surface observation unit 50B is configured to observe the laminate 10. This is an observation unit that observes through the stage 7 from the side (referred to as the back side) placed on the stage 7. Further, the stage 7 can be moved in the horizontal direction by a moving mechanism 7m.

  The moving mechanism 7m moves the stage 7 in a predetermined XY 2-axis direction within a horizontal plane by the action of a driving unit (not shown). Thereby, the movement of the stage 7 between the front surface observation unit 50A and the back surface observation unit 50B, the movement of the observation position in each observation unit, and the movement of the laser light irradiation position are realized. That is, in the laser processing apparatus 50, the stage 7 is moved by the moving mechanism 7m, so that the front side observation by the front surface observation unit 50A and the back side observation by the back surface observation unit 50B can be switched. ing. Thereby, the optimal observation according to the material and state of a workpiece can be performed flexibly and promptly. As for the moving mechanism 7m, it is more preferable for alignment and the like that the rotation (θ rotation) in the horizontal plane around the predetermined rotation axis can be performed independently of the horizontal drive.

  The surface observation unit 50A is also configured to irradiate the workpiece placed on the stage 7 with laser light. That is, the surface observation unit 50 </ b> A is also a laser beam irradiation unit in the laser processing apparatus 50. This is realized, for example, by configuring the laser irradiation system and the observation optical system coaxially. More specifically, the surface observation unit 50A can be realized by having the same configuration as the basic configuration of the laser processing apparatus disclosed in Patent Document 1.

  More specifically, in the surface observation unit 50A, the laser light LB is emitted from the laser light source SL, reflected by a half mirror 51 provided in a lens barrel (not shown), and then the laser light LB is subjected to surface observation. The light is condensed by the condenser lens 18 so as to be focused at the part to be processed of the work piece placed on the stage 7 with the stage 7 positioned on the part 50A, and is irradiated on the work piece. It is possible to realize processing of a workpiece, for example, formation or ablation of a melt-modified region that is a starting point of division.

  On the other hand, in the surface observation unit 50A, the epi-illumination light L5 emitted from the epi-illumination light source S5 is reflected by a half mirror 52 provided in a lens barrel (not shown) and collected by the condenser lens 18. In addition, the workpiece is irradiated coaxially with the laser beam LB (in a state where the stage 7 is positioned on the surface observation unit 50A). The surface observation unit 50A includes surface observation means 16 including a CCD camera 16a provided above the half mirror 52 (above the lens barrel) and a monitor 16b connected to the CCD camera 16a. The bright field image of the workpiece can be observed in real time in a state where the illumination light L5 is irradiated.

  When the processing position is determined based on the observation image obtained in the surface observation unit 50A, it is possible to continue processing by irradiation with the laser beam LB based on the determined content.

  It should be noted that the processing position can be determined using a GUI realized by a control means (not shown) while the operator of the laser processing apparatus 50 can visually recognize the image captured by the CCD camera 16a displayed on the monitor 16b. It is preferable to be made. That is, it is preferable that a predetermined instruction input for determining the machining position by the operator is given by the GUI, and the machining position is determined by the control means performing a predetermined calculation process based on the input content.

  The back surface observation unit 50B is based on the above-described principle configuration, and the coaxial illumination light source S1 from above the stage 7 with respect to the workpiece placed on the stage 7 with the stage 7 positioned on the back surface observation unit 50B. So that the workpiece can be observed from the lower side of the stage 7 by the back surface observation means 6 while performing the irradiation of the coaxial transmitted illumination light L1 and the oblique transmitted light L2 from the oblique illumination light source S2 in a superimposed manner. It is configured.

  Further, in the back surface observation unit 50B, a CCD camera 6a provided below the stage 7, more preferably below a half mirror 9 described below (below the lens barrel), and a monitor 6b connected to the CCD camera 6a. The back surface observation means 6 containing these is provided. Note that the monitor 6b and the monitor 16b provided in the surface observation means 16 may be the same.

  A workpiece is a device in which a device pattern 3 is formed on a transparent substrate 1, and an adhesive sheet 4 is attached to the side on which the device pattern 3 is formed, and then fixed to a stage 7. In the case of the laminated body 10, the stage 7 is arranged at a predetermined observation position of the back surface observation unit 50B, and is observed by the back surface observation means 6 in a state where the coaxial transmission illumination light L1 and the oblique light transmission illumination light L2 are irradiated in a superimposed manner. By performing the above, the device pattern 3 can be observed with a good contrast. That is, for example, an observation image capable of accurately specifying the device pattern 3 as shown in FIG. 1B can be obtained.

  When the processing position is determined based on the observation image obtained in the back surface observation unit 50B, the stage 7 is moved to the side of the surface observation unit 50A where the laser beam irradiation unit is located, and then the laser beam LB Processing by irradiation will be performed. Also in this case, the processing position is preferably determined by giving a predetermined instruction input by the operator based on the observation image using the GUI.

  Preferably, the surface observation unit 50A may include an oblique illumination light source S6 so that the workpiece on the stage 7 can be irradiated with the oblique illumination light L6. When the oblique illumination light L6 is irradiated, the surface observation means 16 can obtain a dark field image to be observed. By appropriately switching between the incident illumination light L5 and the oblique illumination light L6 according to the material and surface state of the workpiece, a suitable observation image can be obtained regardless of the material.

  Below the stage 7, the coaxial illumination light L 3 emitted from the coaxial illumination light source S 3 is reflected by a half mirror 9 provided in a lens barrel (not shown) and collected by a condenser lens 8. Thus, the workpiece may be irradiated via the stage 7. More preferably, the oblique illumination light source S4 may be provided below the stage 7, and the workpiece may be irradiated with the oblique illumination light L4 via the stage 7. The coaxial illumination light source S3 and the oblique illumination light source S4 have, for example, an opaque metal layer on the surface side of the workpiece, and are difficult to observe from the surface side by the surface observation unit 50A due to reflection from the metal layer. In such a case, it can be suitably used when the back surface side of the workpiece is observed by the back surface observation unit 50B.

  As described above, the laser processing apparatus 50 according to the present embodiment includes the surface observation unit 50A that performs irradiation and observation of illumination light from the surface side of the workpiece when processing with laser light, By providing a back surface observation unit 50B that can perform observation from the back surface side while irradiating transmitted illumination from the surface side of the workpiece, not only observation from the surface side of the workpiece by epi-illumination but also from the back surface Observation can also be performed, and a processing position can be specified based on each observation result, so that workpieces of various materials and states can be processed. In particular, for the laminate 10 in which the device pattern is formed on the transparent substrate, the adhesive sheet 4 is attached to the side on which the device pattern is formed, and then fixed to the transparent stage 7 to observe the back surface. By observing at the part 50B, the shape of the device pattern can be clearly specified. This makes it possible to determine the machining position with high accuracy based on the observation result.

<2. Second Embodiment>
In the above embodiment, for example, in the back surface observation unit 50B of the laser processing apparatus 50, the laminated body 10 is irradiated with the coaxial illumination light L1 having an incident angle of 90 ° and the oblique illumination light L2 having an acute incident angle at the same time. However, the observation method is not limited to this.

  FIG. 4 is a schematic diagram schematically showing a configuration of a laser processing apparatus 500 according to the second embodiment. In addition, about the structure similar to the laser processing apparatus 50 which concerns on 1st Embodiment, a same sign is attached | subjected and description is abbreviate | omitted suitably.

  The laser processing apparatus 500 includes a control unit C including a general computer. The control unit C is connected to each mechanism attached to the laser processing apparatus 500 by a cable (not shown), and controls each mechanism of the laser processing apparatus 500 based on an input instruction from an operator and signals from various sensors. .

  Although not shown in FIG. 3, the laser processing apparatus 50 according to the first embodiment also includes a control unit composed of a general computer or the like, and each control described above is controlled by the control unit. Done under. However, as will be described later, the control unit C used in the laser processing apparatus 500 according to the second embodiment performs the alternate irradiation control of two types of irradiation light and the case where each irradiation light is generated independently. It has a function different from that of the control unit in the first embodiment in that it performs an image composition calculation of two types of observation images.

  FIG. 5 is a diagram illustrating an example of an observation image I2 captured by the camera 6a when the coaxial illumination light L1 is irradiated. FIG. 6 is a diagram illustrating an example of an observation image I3 captured by the camera 6a when the oblique illumination light L2 is irradiated.

  In the present embodiment, the control unit C drives the coaxial illumination light source S1 and the oblique illumination light source S2 independently of each other, thereby separately supplying the coaxial illumination light L1 and the oblique illumination light L2 to the stacked body 10, That is, irradiation is performed with a time shift. When the control unit C irradiates only the coaxial illumination light L1 to the stacked body 10 and the observation image I2 captured by the camera 6a, and the oblique light illumination L2 only to the stacked body 10 The observation image I3 picked up by the camera 6a is stored in a storage unit (not shown) provided in the control unit C. Note that the order in which the observation image I2 and the observation image I3 are acquired may be first.

  In the present embodiment, the camera 6a acquires a monochrome (binary) image using 1-bit representation (2 gradations). However, the present invention is not limited to this, and a plurality of bits is used. A binary image with monochrome multi-gradation (for example, 4 bits = 16 gradations, 8 bits = 256 gradations) may be acquired. However, “multi-gradation” here simply means that each pixel is represented by a plurality of bits, and actually two levels of “black” and “white” (for example, gradation in 4-bit representation). In a value = 0, 15, 8-bit expression, gradation value = 0, 255) is used. In addition, the back surface observation unit 50B may be configured to capture a gray scale (or full color) observation image with the camera 6a and to make the observation image monochrome (binarization) in the control unit C.

  When the laminated body 10 placed on the stage 7 is irradiated with the coaxial illumination light L1 from the upper side and imaged by the camera 6a from the lower side of the laminated body 10 (the side opposite to the irradiation), as shown in FIG. In addition, an observation image I2 of a bright field image is acquired. In the observed image I2, a dark (black) device pattern image IP2 is observed for the device pattern 3 portion. That is, the device pattern 3 itself is observed so as to be distinguishable with high contrast with respect to the transparent substrate 101. Furthermore, as shown in FIG. 5, the observation image IB2 corresponding to the bubble 5 is also observed dark due to the refraction of the illumination light.

  On the other hand, when the laminated body 10 placed on the stage 7 is irradiated with the oblique illumination light L2 from the upper side and imaged by the camera 6a from the lower side (the opposite side to the irradiation), FIG. As shown, an observation image I3 of a dark field image is acquired. When compared with the observation image 12, in the observation image I3, as shown in FIG. 5, the light and darkness of the part other than the device pattern image IP3 is reversed. That is, the portion corresponding to the device pattern 3 is observed as a dark device pattern image IP3, while the portion IB3 corresponding to the bubble 5 is observed brightly (as white).

  FIG. 7 is a diagram showing a composite image I4 synthesized based on the observation image I2 shown in FIG. 5 and the observation image I3 shown in FIG. The control unit C that stores the observation image I2 and the observation image I3 in the storage unit performs bit operation processing (specifically, logical sum operation processing) by a calculation unit (not shown) based on the observation images I2 and I3. . More specifically, the calculation unit determines that the gradation value of the specific pixel included in the observation image I2 and the gradation value of the pixel included in the observation image I3 that corresponds to the specific pixel are both “black”. When (gradation value = 0) ", processing for setting the gradation value of the specific pixel to 0 is performed. Further, other combinations (that is, at least one of the gradation value of the specific pixel included in the observation image I2 and the gradation value of the pixel included in the observation image I3 positionally corresponding to the specific pixel). When the tone value is “white (gradation value = 1)”), a process of always setting the gradation value of the specific pixel to 1 is performed. The control unit C obtains a composite image I4 as shown in FIG. 7 by performing the arithmetic processing as described above.

  As shown in FIG. 7, in the composite image I4, the portion IB4 corresponding to the bubble 5 has almost disappeared, and the portion corresponding to the device pattern 3 (device pattern image IP4) has a high contrast with respect to the transparent substrate 1. Identified by That is, in this embodiment, when observing the laminated body 10 in the back surface observation unit 50B, the coaxial illumination light L1 and the oblique illumination light L2 are separately irradiated, and the observation images I2 and I3 are acquired and controlled. The image is stored in the storage means in the part C, and thereafter, the observation images I2 and I3 are synthesized (OR operation processing) by arithmetic processing. This makes it possible to clearly identify the transparent portion of the transparent substrate 1 and the opaque portion of the device pattern 3.

  In the first embodiment, since the coaxial illumination light L1 and the oblique illumination light L2 are simultaneously irradiated, when adjusting the light amount or the like, one of the light amounts needs to be fixed and adjusted. For this reason, for example, when adjusting the amounts of both illumination lights in three stages, a total of nine (= 3 × 3) imaging operations are required. On the other hand, in the present embodiment, a total of nine patterns of images can be synthesized by the control unit C by performing a total of six (= 3 + 3) imaging operations, so that the illumination-related adjustment time in the back surface observation unit 50B is shortened. can do.

  Although detailed description is omitted, the observation method as described above can also be applied to the case where observation is performed by irradiating the laminated body 10 with the coaxial illumination light L3 and the oblique illumination light L4 in the back surface observation unit 50B. it can.

<3. Modification>
In the above-described embodiment, the oblique illumination light source S2 is, for example, a white LED or the like so that the irradiation direction of the coaxial transmitted illumination light L1 is a symmetric axis. An embodiment in which a surrounding donut-shaped illumination light source or a dome-shaped illumination light source is used as the oblique illumination light source S2 may be used.

  In the first embodiment described above, the coaxial illumination light L1 and the oblique illumination light L2 are superposed as transmitted illumination light from the upper side of the stage, and observation is performed by the back surface observation means 6 provided below the stage. However, instead of this, in the state where the laminate 10 in which the device pattern 3 is formed on the transparent substrate 1 is fixed to the stage 7 using the adhesive sheet 4 in the same manner as described above. Alternatively, the coaxial illumination light L1 and the oblique illumination light L2 may be applied in a superimposed manner from below the observation light 7 and the observation unit 26 provided above the stage 7 may be used for observation. FIG. 8 is a diagram for explaining an observation method in such a case. Also in this case, in the observation image, a dark (black) device pattern image is observed corresponding to the device pattern 3, and portions other than the device pattern image IP1 are observed brightly. Further, the portion IB1 corresponding to the bubble 5 is also observed sufficiently brightly. That is, even when observation is performed with the configuration shown in FIG. 8, the black device pattern image is clearly identified with sufficient contrast from other portions. Also, the observation method described in the second embodiment may be applied to the configuration of the observation apparatus according to such a modification.

  Note that this aspect can be realized, for example, by providing irradiation light sources of the coaxial illumination light L1 and the oblique illumination light L2 below the stage 7 in the surface observation unit 50A of the laser processing apparatus 50 described above. In some cases, the laser light that is sometimes irradiated passes through the stage 7 and reaches these irradiation light sources, which may adversely affect these illumination light sources. It is necessary to devise the arrangement of the illumination light source. This also causes a demerit that the device configuration becomes complicated. It can be said that the above-described embodiment is superior in that such consideration is unnecessary.

  Alternatively, the stage arrangement need not be horizontal, but may be provided vertically or inclined. In such a case, the illumination light source and the observation means may be arranged so that the relative positional relationship with the stage is the same as that shown in FIG.

  In the above-described embodiment, the laminate to be observed is fixed on the transparent stage. Instead, the observation means irradiates the coaxial transmission illumination light and the oblique transmission illumination light. As long as the pattern can be obtained, the fixing method is not limited to this. For example, the laminated body other than the observation target part (for example, only the end part) is held together with the adhesive sheet by a predetermined supporting means, and the observation target part (the adhesive sheet) is directly exposed to the observation means. Even if it performs, it is possible to obtain the observation result similar to the above-mentioned embodiment.

  In the above-described embodiment, the device pattern 3 is the main observation target, but the observation is aimed at discriminating the more general opaque portion formed on the transparent substrate from the surrounding portion. When performing the above, the above-described observation method can be similarly applied.

  Moreover, in the laser processing apparatuses 50 and 500 which concern on the above-mentioned embodiment, the position of the device pattern 3 (opaque part) is pinpointed in detail in the back surface observation part 50B. Then, the laser processing apparatuses 50 and 500 move the stage 7 toward the surface observation unit 50A by the moving mechanism 7m, thereby conveying the stacked body 10 to the surface observation unit 50A and forming a division starting point on the transparent substrate 1. For laser processing. That is, in the laser processing apparatuses 50 and 500, the back surface observation unit 50B and the moving mechanism 7m mainly have a function as a positioning mechanism. When an opaque part such as the device pattern 3 is formed on the transparent substrate 1, the substrate can be accurately positioned by applying such a positioning mechanism.

It is a figure for demonstrating the observation method which concerns on the 1st Embodiment of this invention. It is a figure shown in detail about irradiation of the coaxial transmission illumination light L1 and irradiation of the oblique transmission illumination light L2. 2 is a schematic diagram schematically showing the configuration of a laser processing apparatus 50. FIG. It is a schematic diagram which shows schematically the structure of the laser processing apparatus 500 which concerns on 2nd Embodiment. It is a figure which shows an example of the observation image I2 imaged by CCD camera 6a when irradiated with the coaxial illumination light L1. It is a figure which shows an example of the observation image I3 imaged with the CCD camera 6a when the oblique illumination light L2 is irradiated. FIG. 7 is a diagram showing a composite image I4 synthesized based on the observation image I2 shown in FIG. 5 and the observation image I3 shown in FIG. It is a figure for demonstrating the observation method which concerns on a modification. It is a figure for demonstrating the case where the laminated body in which the diffusion layer is provided between the device pattern and the transparent substrate is observed using epi-illumination. It is a figure for demonstrating the case where the laminated body in which the diffusion layer is provided between the device pattern and the transparent substrate is observed using transmitted illumination.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Transparent substrate 2,102 Diffusion layer 3,103 Device pattern 4,104 Adhesive sheet 5,105 Air bubble 6 Back surface observation means 6a, 16a CCD camera 6b, 16b Monitor 10, 100 Laminate 16 Surface observation means 7, 107 207 Stage 7m Moving mechanism 26, 106 Observation means 50, 500 Laser processing device 50A Front surface observation unit 50B Back surface observation unit C Control unit D Diffusion plate I1, I2, I3, I1001, I1002 Observation image I4 Composite image IP1, IP2, IP3 , IP1001, IP1002 Device pattern image L1 Coaxial (transmitted) illumination light L1t, L1002t Transmitted light L2 Oblique light (transmitted) illumination light L3 Coaxial illumination light L4, L6 Oblique light illumination L5, L1001 Incident illumination light L1002 Transmitted illumination light LB Laser light S1 , S3 coaxial lighting Source S2, S4, S6 oblique illumination light source S5 epi-illumination light source SL laser source

Claims (23)

A laser processing apparatus comprising an observation device for observing an opaque portion formed on one main surface side of a transparent substrate that is a workpiece,
The observation device includes:
A support means for supporting the transparent substrate;
A coaxial illumination light source that emits coaxial illumination light;
An oblique illumination light source for irradiating oblique illumination light;
Observation means for observing the transparent substrate from the first main surface side of the transparent substrate;
With
The support means supports the transparent substrate so that the observation means can observe,
The coaxial illumination light source and the oblique light source are the coaxial illumination light and the oblique light with respect to the transparent substrate from the second principal surface side which is the principal surface opposite to the first principal surface of the transparent substrate. Irradiate each with illumination light,
Laser processing equipment characterized by that. The laser processing apparatus according to claim 1,
Laser processing characterized in that the observation means acquires an observation image of the transparent substrate in a state where the coaxial substrate and the oblique illumination light are superimposedly irradiated on the transparent substrate. apparatus. The laser processing apparatus according to claim 2,
A first observation image observed by the imaging unit when the coaxial substrate is irradiated with the coaxial illumination light, and a second observation image observed by the imaging unit when the oblique illumination light is irradiated on the transparent substrate. A synthesis means for obtaining a composite image with the observation image;
A laser processing apparatus, further comprising: A positioning device including an observation device for observing an opaque portion formed on one main surface side of a transparent substrate,
The observation device includes:
A support means for supporting the transparent substrate;
A coaxial illumination light source that emits coaxial illumination light;
An oblique illumination light source for irradiating oblique illumination light;
Observation means for observing the transparent substrate from the first main surface side of the transparent substrate;
With
The support means supports the transparent substrate so that the observation means can observe,
The coaxial illumination light source and the oblique light source are the coaxial illumination light and the oblique light with respect to the transparent substrate from the second principal surface side which is the principal surface opposite to the first principal surface of the transparent substrate. Irradiate each with illumination light,
A positioning device characterized by that. The positioning device according to claim 4,
The positioning apparatus, wherein the observation means acquires an observation image of the transparent substrate in a state where the coaxial illumination light and the oblique illumination light are superimposedly irradiated on the transparent substrate. . The positioning device according to claim 4,
A first observation image observed by the imaging unit when the coaxial substrate is irradiated with the coaxial illumination light, and a second observation image observed by the imaging unit when the oblique illumination light is irradiated on the transparent substrate. A synthesis means for obtaining a composite image with the observation image;
A positioning device further comprising: An observation device for observing an opaque portion formed on one main surface side of a transparent substrate,
A support means for supporting the transparent substrate;
A coaxial illumination light source that emits coaxial illumination light;
An oblique illumination light source for irradiating oblique illumination light;
Observation means for observing the transparent substrate from the first main surface side of the transparent substrate;
With
The support means supports the transparent substrate so that the observation means can observe,
The coaxial illumination light source and the oblique light source are the coaxial illumination light and the oblique light with respect to the transparent substrate from the second principal surface side which is the principal surface opposite to the first principal surface of the transparent substrate. Irradiate each with illumination light,
An observation apparatus characterized by that. The observation device according to claim 7,
An observation apparatus, wherein the observation means acquires an observation image of the transparent substrate in a state where the coaxial illumination light and the oblique illumination light are superimposedly irradiated on the transparent substrate. . The observation device according to claim 7,
A first observation image observed by the imaging unit when the coaxial substrate is irradiated with the coaxial illumination light, and a second observation image observed by the imaging unit when the oblique illumination light is irradiated on the transparent substrate. A synthesis means for obtaining a synthesized image by arithmetic synthesis with the observed image;
An observation apparatus further comprising: An observation apparatus according to any one of claims 7 to 9,
By adjusting the irradiation state of at least one of the coaxial illumination light and the oblique illumination light on the transparent substrate, the amount of light in the observation region grasped by the observation means can be adjusted.
An observation apparatus characterized by that. The observation device according to claim 10,
For at least one of the coaxial illumination light source and the oblique illumination light source, the distance from the opaque substrate is adjustable.
An observation apparatus characterized by that. The observation device according to claim 10,
The brightness of at least one of the coaxial illumination light source and the oblique illumination light source is configured to be adjustable.
An observation apparatus characterized by that. The observation device according to claim 10,
It is configured such that an irradiation angle of the oblique illumination light to the opaque substrate can be adjusted.
An observation apparatus characterized by that. An observation apparatus according to any one of claims 7 to 13,
The support means is a transparent stage;
The observation means observes the transparent substrate through the stage;
An observation apparatus characterized by that. The observation device according to any one of claims 7 to 14,
Irradiating the coaxial illumination light and the oblique illumination light toward the transparent substrate from above the transparent substrate supported by the support means,
The observation means observes the transparent substrate from below the transparent substrate;
An observation apparatus characterized by that. A method of observing an opaque portion formed on one main surface side of a transparent substrate,
In a state where the transparent substrate is supported by a predetermined support means,
While irradiating coaxial illumination light and oblique illumination light in a superimposed manner from one side of the transparent substrate toward the transparent substrate, the transparent substrate is applied from the other side of the transparent substrate by a predetermined observation means. Observe,
A method for observing an opaque portion on a transparent substrate. The observation method according to claim 16, wherein
About at least one of the coaxial illumination light and the oblique illumination light so that the amount of light other than the opaque portion of the transparent substrate in the observation region grasped by the observation means is substantially the same for the entire observation region. Adjusting the irradiation status of
A method for observing an opaque portion on a transparent substrate. The observation method according to claim 17,
Adjusting the irradiation state by adjusting a distance between at least one of the coaxial illumination light source for irradiating the coaxial illumination light and the oblique illumination light source for irradiating the oblique illumination light and the transparent substrate;
A method for observing an opaque portion on a transparent substrate. The observation method according to claim 17,
Adjusting the irradiation state by adjusting at least one of the luminance of the coaxial illumination light source that irradiates the coaxial illumination light and the luminance of the oblique illumination light source that irradiates the oblique illumination light;
A method for observing an opaque portion on a transparent substrate. The observation method according to claim 17,
Adjusting the irradiation state by adjusting an irradiation angle of the oblique illumination light to the opaque substrate;
A method for observing an opaque portion on a transparent substrate. The observation method according to any one of claims 16 to 20,
The support means is a transparent stage;
Support the transparent substrate by fixing the transparent substrate to the stage with the other side facing the stage,
The observation means observes the transparent substrate through the stage;
A method for observing an opaque portion on a transparent substrate. The observation method according to any one of claims 16 to 21,
Irradiating the coaxial illumination light and the oblique illumination light toward the transparent substrate from above the transparent substrate supported by the support means,
The observation means observes the transparent substrate from below the transparent substrate;
A method for observing an opaque portion on a transparent substrate. A method of observing an opaque portion formed on one main surface side of a transparent substrate,
In a state where the transparent substrate is supported by a predetermined support means,
(a) imaging a first observation image by a predetermined imaging means from the other side of the transparent substrate while irradiating coaxial illumination light from one side of the transparent substrate toward the transparent substrate;
(b) imaging a second observation image by a predetermined imaging means from the other side of the transparent substrate while irradiating oblique illumination light from one side of the transparent substrate toward the transparent substrate;
(c) creating a composite image of the first observation image and the second observation image;
A method for observing an opaque portion on a transparent substrate, comprising: