Curved surface photographing device and dicing device

Abstract

To provide a calf photographing device and a dicing device capable of recognizing a calf well at low cost within a short time.SOLUTION: A calf photographing device for photographing a calf formed along a street of a workpiece W from a surface side of the workpiece W comprises: a coaxial illumination unit 52 (first illumination unit) that illuminates a calf forming region CR with coaxial illumination light L1 (first illumination light) from the surface side of the workpiece W; an infrared light source 50 (second illumination unit) that illuminates the forming region CR with infrared light Li (second illumination light) of an infrared wavelength region different from a wavelength region of the coaxial illumination light L1 from a backside of the workpiece W; and an imaging unit into which mixed light LM of regular reflected light L1A of the coaxial illumination light L1 reflected in the forming region CR and transmission light LT of the infrared light Li passed from the backside of the workpiece W through the forming region CR and emitted from the front side of the workpiece W enters, and which separates the mixed light LM into the regular reflected light L1A and the transmission light LT to simultaneously image them.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a kerf photographing device and a dicing device that photograph a kerf formed along a street of a workpiece.

Background Art

[0002] There is known a dicing device that dices (cuts) a workpiece such as a silicon wafer with a disk-shaped blade rotated at high speed by a spindle (see Patent Document 1). This dicing device performs dicing processing to form a kerf (groove) along a street by moving a blade that rotates at high speed along a street (also referred to as a division planned line) formed in a grid pattern on the workpiece. Further, as such a dicing device, a twin spindle dicer having two spindles to which blades are attached is known. And, as a method of cutting or severing a workpiece by this twin spindle dicer, a meeting cutting method and a step cut method are known.

[0003] The meeting cutting method is a method of cutting two streets at once with two blades. Further, the step cut method is a method of cutting a workpiece along a street by cutting a first kerf having a predetermined depth along the street with a first blade, and then dicing the bottom of the first kerf with a second blade to form a second kerf.

[0004] Since the blade of such a dicing device wears out during use, chipping may occur on the cut surface of the workpiece by the blade. Further, due to the influence of thermal deformation of the blade, the position of the kerf formed in the workpiece by the blade may deviate from the center of the street. For this reason, in the dicing device, a kerf check of the blade is performed at a preset timing.

[0005] For example, in the dicing device described in Patent Document 1, the kerf formed on the workpiece is illuminated by coaxial illumination with a microscope and photographed while being illuminated by oblique light illumination from an oblique direction, and a kerf check is performed to measure the position of the kerf (displacement from the target value) based on the photographed image of this microscope.

[0006] Further, the dicing device described in Patent Document 2 above includes a white interferometer that emits white light toward the formation region (processing region) of the kerf formed on the workpiece and detects an interference signal between the white light reflected in this processing region and the white light reflected on the reference surface. This dicing device vertically scans the white interferometer in the Z-axis direction and acquires the interference signals output from each pixel of the white interferometer (pixels of the imaging element that images the interference signal) at each position in the Z-axis direction. Then, the dicing device performs a kerf check by generating a three-dimensional image of the processing region based on the interference signal for each pixel.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] FIG. 17 is an explanatory diagram for explaining the problems in the case of performing a kerf check based on a photographed image of a kerf photographed by a microscope. Here, a first kerf 25A and a second kerf 25B are formed on the workpiece W by a step cut method, and a dicing tape T is adhered to the back surface of the workpiece W.

[0009] In the dicing apparatus described in Patent Document 1 above, the kerf is photographed with a microscope. However, as shown in FIG. 17, for example, the processing depth of the kerfs (the first kerf 25A and the second kerf 25B) formed by the above-described step cut method becomes deeper. In this case, the reflected light of the coaxial illumination light L1 irradiated from the microscope toward the bottom of the first kerf 25A is not reflected upward. Also, the bottom of the second kerf 25B hardly reflects the coaxial illumination light L1. Furthermore, the oblique illumination light L2 irradiated from the microscope does not reach at least the bottom of the second kerf 25B. For this reason, in the photographed image of the microscope, the images of the first kerf 25A and the second kerf 25B become dark, and particularly, since there is no luminance difference at the edge of the second kerf 25B, it is difficult to detect the position of the second kerf 25B.

[0010] Therefore, it is conceivable to perform an overtake kerf check in which an uncut portion of the work W is cut by the first blade and another uncut portion of the work W is cut by the second blade, and the kerf check of each blade is performed based on the photographed images of the two kerfs formed by each blade photographed with a microscope. However, in the overtake kerf check, the positional relationship between the first kerf 25A formed by the first blade and the second kerf 25B formed by the second blade cannot be recognized.

[0011] Also, it is conceivable to use a microscope with a large NA (Numerical Aperture). In this case, however, the depth of focus of the microscope becomes shallow. For this reason, unless the focus position of the microscope is changed when photographing the pattern on the surface of the work W and each of the kerfs 25A and 25B, the image of either the pattern or each of the kerfs 25A and 25B will become unclear.

[0012] Furthermore, when performing a kerf check using a white interferometer as in the dicing apparatus described in Patent Document 2 above, a vertical scanning mechanism of the white interferometer is required, and furthermore, it is necessary to analyze a large-capacity interference signal, which has problems of high cost and time consumption.

[0013] The present invention has been made in view of such circumstances, and an object thereof is to provide a kerf imaging device and a dicing device that can recognize a kerf well at low cost and in a short time.

Means for Solving the Problems

[0014] A kerf imaging device for achieving the object of the present invention is a kerf imaging device that images a kerf formed along a street of a workpiece from the surface side of the workpiece. The kerf imaging device includes a first illumination unit that irradiates a first illumination light to a formation region of the kerf from the surface side of the workpiece, a second illumination unit that irradiates a second illumination light in an infrared wavelength range different from the wavelength range of the first illumination light to the formation region from the back side of the workpiece, and an imaging unit into which a mixed light of a reflected light of the first illumination light reflected in the formation region and a transmitted light of the second illumination light that has passed through the formation region from the back side of the workpiece and is emitted from the surface side of the workpiece is incident, and the imaging unit that separates the mixed light into the reflected light and the transmitted light and simultaneously images them.

[0015] According to this microscope, the pattern on the workpiece surface can be recognized based on the image obtained by imaging the reflected light, and the edge information of the kerf can be recognized based on the image obtained by imaging the transmitted light.

[0016] In a kerf imaging device according to another aspect of the present invention, the imaging unit is a color imaging device including a plurality of pixels arranged in a two-dimensional array and a plurality of color filters disposed on the plurality of pixels. The plurality of color filters include a plurality of first color filters that transmit only the first illumination light and a plurality of second color filters that transmit only the second illumination light. Thereby, the mixed light can be separated into the reflected light and the transmitted light and imaged simultaneously and coaxially.

[0017] In the kerf imaging device according to another aspect of the present invention, the imaging unit includes an optical separation element that separates mixed light into first light and second light, a first filter disposed on the optical path of the first light separated by the optical separation element and transmitting only reflected light, a first imaging element that images the reflected light transmitted through the first filter, a second filter disposed on the optical path of the second light separated by the optical separation element and transmitting only transmitted light, and a second imaging element that images the transmitted light transmitted through the second filter. Thereby, the mixed light can be separated into reflected light and transmitted light and imaged simultaneously and coaxially, and a higher-resolution image can be obtained.

[0018] In the kerf imaging device according to another aspect of the present invention, the imaging unit includes a wavelength separation element that wavelength-separates mixed light into reflected light and transmitted light, a first imaging element that images the reflected light wavelength-separated by the wavelength separation element, and a second imaging element that images the transmitted light wavelength-separated by the wavelength separation element. Thereby, the mixed light can be separated into reflected light and transmitted light and imaged simultaneously and coaxially, and a higher-resolution image can be obtained. Further, the number of components of the microscope can be reduced, so that the microscope can be miniaturized and cost-reduced.

[0019] In the kerf imaging device according to another aspect of the present invention, a table for holding the workpiece from the back side of the workpiece is provided, and a second illumination unit is provided on the table.

[0020] In the kerf imaging device according to another aspect of the present invention, the first illumination unit irradiates the formation region with coaxial illumination light as the first illumination light. Thereby, a bright-field image of the formation region can be obtained.

[0021] In the kerf imaging device according to another aspect of the present invention, the first illumination unit irradiates the forming region with coaxial illumination light as the first illumination light and oblique illumination light having a wavelength range different from that of the coaxial illumination light from an oblique direction. The reflected light includes the specular reflection light of the coaxial illumination light specularly reflected by the forming region and the scattered light of the oblique illumination light scattered by the forming region. The imaging unit separates and simultaneously images the specular reflection light and the scattered light. As a result, a bright-field image and a dark-field image of the forming region can be obtained, so that patterns that are difficult to recognize only with the bright-field image can also be recognized, and the kerf becomes easier to recognize.

[0022] In the kerf imaging device according to another aspect of the present invention, when the kerf includes a first kerf formed on the surface side of the workpiece and a second kerf formed at the bottom of the first kerf, the imaging unit images the reflected light to generate a first captured image including an image of the pattern formed on the surface of the workpiece and an image of the first kerf, and images the transmitted light to generate a second captured image including an image of the second kerf. As a result, all of the pattern on the surface of the workpiece, the first kerf, and the second kerf with a deep processing depth can be recognized.

[0023] The kerf imaging device according to another aspect of the present invention includes an image processing unit that synthesizes the image of the second kerf in the second captured image with the first captured image to generate a synthesized image. As a result, all of the pattern on the surface of the workpiece, the first kerf, and the second kerf with a deep processing depth can be recognized.

[0024] A dicing device for achieving the object of the present invention is a dicing device that forms a kerf along the street of the workpiece from the surface side of the workpiece, and includes the above-described kerf imaging device.

Effects of the Invention

[0025] The present invention can recognize a kerf well at low cost and in a short time.

Brief Description of the Drawings

[0026]

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Figure 17

Mode for Carrying Out the Invention

[0027] [First Embodiment] FIG. 1 is a perspective view of a dicing apparatus 10 according to the first embodiment. In the figure, the XYZ axes are orthogonal to each other, the XY axes are parallel to the horizontal direction, and the Z axis is orthogonal to the horizontal direction.

[0028] As shown in FIG. 1, the dicing apparatus 10 includes a kerf photographing apparatus (such as the microscope 23 and the infrared light source 50 in FIG. 5) of the present invention, and dices a flat workpiece W such as a silicon wafer (semiconductor wafer). This dicing apparatus 10 includes a load port 12, a transfer mechanism 14, a processing unit 16, and a cleaning unit 18.

[0029] A cassette storing a large number of workpieces W mounted on the frame F is placed on the load port 12. The transfer mechanism 14 transfers the workpiece W. The processing unit 16 performs dicing processing on the workpiece W. The cleaning unit 18 spin-cleans the diced workpiece W. Further, inside the housing 10A of the dicing apparatus 10, a general control unit 60 (see FIG. 9) for controlling the operations of each part of the dicing apparatus 10 and the like are provided. Note that the general control unit 60 may be provided outside the housing 10A.

[0030] The unprocessed workpiece W stored in the cassette placed on the load port 12 is transferred to the processing unit 16 by the transfer mechanism 14, and dicing processing such as cutting or grooving is performed in the processing unit 16 to divide it into individual chips. Then, the workpiece W processed by the processing unit 16 is transferred to the cleaning unit 18 by the transfer mechanism 14, cleaned by the cleaning unit 18, and then transferred to the load port 12 by the transfer mechanism 14 and stored in the cassette.

[0031] FIG. 2 is an external perspective view of the processing unit 16. As shown in FIG. 2 and the aforementioned FIG. 1, the processing unit 16 is the aforementioned twin spindle dicer, and includes a pair of blades 21A and 21B, a blade cover (not shown), a pair of spindles 22A and 22B, a microscope 23, and a table 31.

[0032] The blades 21A and 21B are formed in a disk shape. Further, the tip shape of the blades 21A and 21B, that is, the cross-sectional shape of the outer peripheral portion (blade tip portion) of the blades along the radial direction is rectangular (other shapes such as V-shaped are also possible). The blades 21A and 21B are arranged to face each other in the Y-axis direction, and are rotatably held by the spindles 22A and 22B around the blade rotation axes parallel to the Y-axis direction, respectively.

[0033] The spindles 22A and 22B incorporate high-frequency motors and rotate the blades 21A and 21B at high speed around the blade rotation axes. As a result, the work W is diced from its surface (device formation surface) side by the blades 21A and 21B. A kerf (groove) is formed in the work W by the dicing of the work W by the blades 21A and 21B.

[0034] The microscope 23 is provided, for example, on the Z carriage 44 integrally with the spindle 22A (or the spindle 22B), and is held movably in the YZ-axis direction integrally with the spindle 22A by the Y carriage 43 and the Z carriage 44. The microscope 23 photographs the pattern and the kerf on the surface of the work W from the surface side of the work W. This microscope 23 is used for the alignment of the work W and the blades 21A and 21B and the kerf check for confirming the position of the kerf.

[0035] The table 31 has a work holding surface 31a formed in a porous shape. The work holding surface 31a adsorbs and holds the work W from its back surface side. At this time, a dicing tape T that can transmit infrared light Li (near-infrared light, see FIG. 4) is attached to the back surface of the work W, and the work holding surface 31a adsorbs and holds the work W via the dicing tape T. Note that the table 31 is held movably in the X-axis direction by an X carriage 36 described later, and is held rotatably around a rotation axis CA by a rotation unit 37 described later.

[0036] Also, inside the table 31, an infrared light source 50 that irradiates infrared light Li upward in the Z direction toward the back side of the work W is provided, which will be described in detail later (see FIG. 4). For this reason, the table 31 is made of a material that can transmit the infrared light Li, for example, infrared-transmitting glass.

[0037] The processing unit 16 is provided with an X base 32, an X guide 34, an X drive unit 35, an X carriage 36, and a rotation unit 37. The X base 32 has a flat plate shape extending in the X-axis direction, and the X guide 34 is provided on the upper surface in the Z-axis direction thereof. The X guide 34 has a shape extending in the X-axis direction and guides the X carriage 36 along the X-axis direction. The X drive unit 35 uses an actuator such as a linear motor, for example, to move (drive) the X carriage 36 along the X guide 34 in the X-axis direction.

[0038] The rotation unit 37 is provided on the upper surface of the X carriage 36. Also, the table 31 is provided on the upper surface of the rotation unit 37. The rotation unit 37 is rotationally driven by a rotation drive unit 38 (see FIG. 9) constituted by a motor, gears, and the like. Thereby, the rotation unit 37 rotates the table 31 in the θ direction about its rotation axis CA.

[0039] The work W conveyed from the load port 12 by the conveyance mechanism 14 is adsorbed and held by the table 31, and thus moves and rotates integrally with the table 31.

[0040] Further, the processing unit 16 is provided with a Y base 41, a Y guide 42, a pair of Y carriages 43, and a pair of Z carriages 44. The Y base 41 has a portal shape that straddles the X base 32 in the Y-axis direction. The Y guide 42 is provided on the side surface of the Y base 41 in the X-axis direction. The Y guide 42 has a shape extending in the Y-axis direction and guides the pair of Y carriages 43 along the Y-axis direction respectively. The pair of Y carriages 43 are independently driven along the Y guide 42 by a Y drive unit 46 (see FIG. 9), which is an actuator composed of, for example, a stepping motor and a ball screw.

[0041] A Z carriage 44 is movably provided in the Z-axis direction on each of the pair of Y carriages 43 via a Z drive unit 48 (see FIG. 9), which is an actuator composed of an actuator such as a stepping motor. One of the Z carriages 44 is provided with a spindle 22A and a microscope 23, and the other of the Z carriages 44 is provided with a spindle 22B.

[0042] By driving the X carriage 36, the rotation unit 37, each Y carriage 43, and each Z carriage 44, the blades 21A, 21B, and the microscope 23 can be relatively moved in the XYZ-axis directions and the θ direction with respect to the table 31 and the workpiece W. Thereby, the position adjustment of the microscope 23 with respect to the workpiece W before the start of alignment, and the alignment of the blades 21A, 21B with respect to the machining start position of the workpiece W after the alignment detection can be performed. Further, during the dicing process of the workpiece W by the blades 21A, 21B, the cutting feed of the workpiece W in the X direction, and the index feed of the blades 21A, 21B in the Y-axis direction and the plunge feed in the Z-axis direction can be performed.

[0043] Since the dicing device 10 is a so-called twin spindle dicer, the processing control unit 78 selectively executes, for example, a meeting cutting method and a step cutting method as the dicing process of the workpiece W. In this embodiment, the case of performing the dicing process by the step cutting method will be described as an example.

[0044] FIG. 3 is an explanatory diagram for explaining the step cut method. As shown in FIG. 3, the step cut method is selected when the workpiece W is a laminate in which a low dielectric constant insulating film (Low-k film) and a functional film for forming a circuit are laminated on the surface of a substrate such as silicon. In this step cut method, blades 21A and 21B having different thicknesses (or blades 21A and 21B having the same shape) are attached to the spindles 22A and 22B. And in the step cut method, for each street C by the blades 21A and 21B, first, the first kerf 25A (see FIG. 17) is formed along the street C by the blade 21A rotating at high speed, and then the second kerf 25B (see FIG. 17) is formed at the bottom of the first kerf 25A along the street C by the blade 21B rotating at high speed.

[0045] Among the first kerf 25A and the second kerf 25B formed by the step cut method, especially the processing depth of the second kerf 25B becomes deep. Therefore, as described with reference to FIG. 17 above, it is difficult to perform a kerf check (hereinafter simply abbreviated as kerf check) for confirming the positions of the first kerf 25A and the second kerf 25B using only the microscope 23. For this reason, in the present embodiment, the kerf check is performed using the infrared light source 50 and the microscope 23.

[0046] [Infrared light source] FIG. 4 is a schematic diagram of the infrared light source 50 provided on the table 31. As shown in FIG. 4, inside the table 31 formed of infrared transmitting glass or the like, an infrared light source 50 corresponding to the second illumination unit of the present invention is provided. As the infrared light source 50, for example, an infrared LED (light emitting diode) is used. This infrared light source 50 irradiates infrared light Li (including near-infrared light), which is the second illumination light of the present invention, toward the upper side in the Z direction during the kerf check, that is, the back side (dicing tape T) of the workpiece W held on the workpiece holding surface 31a.

[0047] Note that the number of infrared light sources 50 is not particularly limited. For example, a plurality of infrared light sources 50 may be two-dimensionally arranged in the table 31 so that the infrared light Li is irradiated to all measurement points (or even the entire area of the work W) where the kerf check is performed within the work W. Further, an infrared light source 50 may be provided at the end of the table 31, and a so-called edge type illumination method may be used in which the infrared light Li emitted from this infrared light source 50 is guided through a light guide plate to a position directly below each measurement point and then refracted upward in the Z direction.

[0048] The infrared light Li emitted from the infrared light source 50 enters the back side of the work W through the dicing tape T and transmits through the work W along the Z direction. As a result, the transmitted light LT of the infrared light Li is emitted from the front side of the work W upward in the Z direction. At this time, a part of the infrared light Li incident on the back side of the work W transmits through the formation regions CR of the first kerf 25A and the second kerf 25B within the work W. Note that the formation regions CR also include the pattern P (which may include a structure) on the surface of the work W formed around the first kerf 25A and the second kerf 25B.

[0049] When the infrared light Li transmits through the formation region CR in this way, a part of the infrared light Li transmits through the dicing tape T and then exits as the transmitted light LT from the front side of the work W through the space within the second kerf 25B. Also, another part of the infrared light Li transmits through the dicing tape T and the silicon region within the work W in sequence and then exits as the transmitted light LT from the front side of the work W through the space within the first kerf 25A. Furthermore, the remaining part of the infrared light Li transmits through the dicing tape TP, then transmits through the silicon region within the work W without passing through the spaces within the first kerf 25A and the second kerf 25B, and then exits as the transmitted light LT from the front side of the work W.

[0050] Here, as the distance that the infrared light Li travels through the silicon region within the work W increases, the amount of infrared light Li absorbed by the silicon region increases, so the amount of transmitted light LT decreases. Conversely, as the distance that the infrared light Li travels through the silicon region within the work W decreases, the amount of infrared light Li absorbed by the silicon region decreases, so the amount of transmitted light LT increases. For this reason, among the transmitted light LT that has passed through the formation region CR, the amount of the transmitted light LT that has passed through the space within the second kerf 25B, that is, the amount of the transmitted light LT indicating the edge information at the bottom of the second kerf 25B, is the largest. Next, the amount of the transmitted light LT that has passed through the first kerf 25A increases, and further, the amount of the transmitted light LT that has not passed through the first kerf 25A and the second kerf 25B is the smallest.

[0051] [Microscope] FIG. 5 is a side view of the microscope 23 of the first embodiment and shows the state during kerf checking. As shown in FIG. 5, the microscope 23 constitutes the kerf photographing device of the present invention together with the infrared light source 50. This microscope 23 performs coaxial illumination on the surface side of the work W during alignment detection (during alignment) of the work W and the blades 21A and 21B and during the aforementioned kerf checking, and photographs the work W from the surface side of the work W.

[0052] The microscope 23 includes a coaxial illumination unit 52 and a color camera 56.

[0053] The coaxial illumination unit 52 corresponds to the first illumination unit of the present invention and irradiates coaxial illumination light L1 (corresponding to the first illumination light of the present invention) onto the formation region CR on the surface of the work W during alignment detection and during kerf checking. This coaxial illumination unit 52 includes a coaxial illumination light source 52a, a half mirror 52b, and an objective lens 52c. The objective lens 52c is disposed at a position facing the surface of the work W and the work holding surface 31a, the half mirror 52b is disposed above the objective lens 52c in the Z direction, and further, the coaxial illumination light source 52a is disposed laterally of the half mirror 52b.

[0054] The coaxial illumination light source 52a uses, for example, an LED (light emitting diode) and emits coaxial illumination light L1 toward the half mirror 52b. For example, white light (visible light) is used as the coaxial illumination light L1. The coaxial illumination light L1 is not particularly limited as long as it has a different wavelength range from the infrared light Li, and visible light, infrared light, etc. may be used.

[0055] The half mirror 52b reflects the coaxial illumination light L1 incident from the coaxial illumination light source 52a toward the objective lens 52c. Further, the half mirror 52b transmits the regular reflection light L1A and the transmitted light LT, which will be described later, incident from the objective lens 52c as they are and emits them toward the color camera 56.

[0056] The objective lens 52c has an optical axis O1 parallel to the Z direction, and irradiates the formation region CR on the surface of the work W with the coaxial illumination light L1 incident from the half mirror 52b along the optical axis O1. As a result, the regular reflection light L1A of the coaxial illumination light L1 regularly reflected in the formation region CR passes through the objective lens 52c and the half mirror 52b in order and enters the color camera 56.

[0057] Further, the transmitted light LT that has passed through the formation region CR during the kerf check enters the objective lens 52c. The transmitted light LT incident on the objective lens 52c passes through the half mirror 52b and enters the color camera 56. Therefore, the mixed light LM of the regular reflection light L1A and the transmitted light LT enters the color camera 56 during the kerf check. Incidentally, if necessary, it is also possible to selectively perform the irradiation of the coaxial illumination light L1 on the surface of the work W by the coaxial illumination unit 52 and the irradiation of the infrared light Li on the back side of the work W by the infrared light source 50.

[0058] The color camera 56 captures the mixed light LM that has passed through the half mirror 52b during alignment detection. Also, during the kerf check, the color camera 56 wavelength-separates the mixed light LM that has passed through the half mirror 52b into the specularly reflected light L1A and the transmitted light LT, and then captures the specularly reflected light L1A and the transmitted light LT individually and simultaneously. Hereinafter, the imaging of the specularly reflected light L1A and the transmitted light LT by the color camera 56 during the kerf check will be specifically described.

[0059] The color camera 56 includes an imaging lens 56a and a color imaging device 56b. The imaging lens 56a forms an image of the mixed light LM incident from the half mirror 52b on the light-receiving surface of the color imaging device 56b.

[0060] FIG. 6 is an enlarged view of a color filter array 58 provided on the light-receiving surface of the color imaging device 56b. As shown in FIG. 6, the color imaging device 56b is, for example, a CCD (Charge Coupled Device) type or CMOS (Complementary Metal Oxide Semiconductor) type two-dimensional imaging device in which a plurality of pixels 57 (light-receiving elements) shown by the dotted frame in the figure are two-dimensionally arranged in the XY direction, and a color filter array 58 is provided on the light-receiving surface side thereof.

[0061] As shown in FIG. 6, the color filter array 58 is composed of a plurality of green color filters 58G indicated by "G" in the figure, blue color filters 58B indicated by "B" in the figure, red color filters 58R indicated by "R" in the figure, and color filters 58IR indicated by "IR" in the figure. Each of the color filters 58R, 58G, 58B, 58IR is arranged on each pixel 57 in an array pattern in which a part of the color filter 58G in a known Bayer array is replaced by the color filter 58IR.

[0062] The color filters 58R, 58G, and 58B correspond to the first color filter of the present invention and transmit only the specular reflection light L1A, which is white light, in the mixed light LM. More specifically, the color filter 58R transmits only red light in the specular reflection light L1A, the color filter 58G transmits only green light in the specular reflection light L1A, and the color filter 58B transmits only blue light in the specular reflection light L1A.

[0063] The color filter 58IR corresponds to the second color filter of the present invention and transmits only the transmitted light LT in the infrared wavelength range in the mixed light LM. As a result, the mixed light LM incident on the color filter array 58 is wavelength-separated into the specular reflection light L1A transmitted through each of the color filters 58R, 58G, and 58B and the transmitted light LT transmitted through the color filter 58IR. As a result, the specular reflection light L1A is imaged by a plurality of pixels 57 for each of the color filters 58R, 58G, and 58B of the color image sensor 56b, and the transmitted light LT is imaged by a plurality of pixels 57 for the color filter 58IR. That is, the specular reflection light L1A and the transmitted light LT are simultaneously imaged in a state where they are separated from each other by the color image sensor 56b.

[0064] In this embodiment, it is only necessary that the color image sensor 56b can simultaneously image the specular reflection light L1A and the transmitted light LT in a state where they are separated from each other. For example, an infrared cut filter (not shown) may be arranged instead of each of the color filters 58R, 58G, and 58B. In this case, by adjusting the arrangements of both the infrared cut filter and the color filter 58IR so that the number of pixels 57 for imaging the specular reflection light L1A and the number of pixels 57 for imaging the transmitted light LT are the same, the number of pixels of the bright-field image D1 and the transmitted image D2 shown in FIGS. 7 and 8 described later can be made the same.

[0065] FIG. 7 is an explanatory diagram showing an example of a bright-field image D1 captured by the color camera 56. As shown in FIG. 7, the bright-field image D1 (corresponding to the first captured image of the present invention) is obtained by imaging the specular reflection light L1A only with a plurality of pixels 57 for each color filter 58R, 58G, 58B of the color imaging device 56b. The bright-field image D1 is a front image of the formation region CR on the surface of the work W photographed under coaxial illumination. Therefore, in the bright-field image D1, the image of the region irradiated with the coaxial illumination light L1 becomes bright, while the image of the region not reached by the coaxial illumination light L1 becomes dark. Specifically, the image of the pattern P in the formation region CR and the image of the first kerf 25A (edge portion) become bright enough to be recognizable, while the image of the second kerf 25B (edge portion) in the formation region CR becomes dark and unrecognizable.

[0066] FIG. 8 is an explanatory diagram showing an example of a transmission image D2 captured by the color camera 56. As shown in FIG. 8, the transmission image D2 (corresponding to the second captured image of the present invention) is obtained by imaging the transmission light LT only with a plurality of pixels 57 for each color filter 58IR of the color imaging device 56b. The transmission image D2 is a monochrome image in which the luminance value for each pixel 57 changes according to the amount of the transmission light LT that has passed through the formation region CR.

[0067] As described above, among the transmission light LT that has passed through the formation region CR, the amount of the transmission light LT that has passed through the space in the second kerf 25B is the largest, and then in order, the transmission light LT that has passed through the space in the first kerf 25A, and the transmission light LT that has not passed through the first kerf 25A and the second kerf 25B, the amount of light becomes smaller. Therefore, in the transmission image D2, the image of the second kerf 25B (edge portion) and the image of the first kerf 25A (edge portion) become bright enough to be recognizable, while the image of the pattern P in the formation region CR becomes dark.

[0068] In this way, the color camera 56 can capture the bright-field image D1 and the transmission image D2 simultaneously and coaxially by separating and imaging the specular reflection light L1A and the transmission light LT from each other.

[0069] [Overall control unit] FIG. 9 is a functional block diagram of the overall control unit 60 of the dicing apparatus 10 according to the first embodiment. As shown in FIG. 9, the overall control unit 60 overall controls each part of the dicing apparatus 10 to execute various operations including alignment detection, alignment, dicing, kerf check, and correction of dicing.

[0070] Connected to the overall control unit 60 are an operation unit 62, a storage unit 64, a display unit 66, etc., in addition to the aforementioned spindles 22A, 22B, microscope 23, X drive unit 35, rotation drive unit 38, Y drive unit 46, and Z drive unit 48.

[0071] The operation unit 62 uses a keyboard, mouse, operation panel, operation buttons, etc., and receives input of various operations by the operator. The storage unit 64 stores a control program (not shown) of the dicing apparatus 10 and various setting information, etc. The display unit 66 uses various known monitors such as a liquid crystal display. This display unit 66 displays images (bright field image D1 and transmission image D2) taken by the microscope 23, a composite image DC generated by an image processing unit 80 described later, and various setting screens of the dicing apparatus 10.

[0072] The overall control unit 60 functions as a blade drive control unit 70, a movement control unit 72, a photographing control unit 74, a detection unit 76, a processing control unit 78, an image processing unit 80, and a measurement unit 82 by executing a control program (not shown) stored in the storage unit 64. Note that what is described as the "~ unit" of the overall control unit 60 may be a "~ circuit", "~ device", or "~ equipment". That is, what is described as the "~ unit" may be composed of any of firmware, software, and hardware or a combination thereof.

[0073] The blade drive control unit 70 controls the rotational drive of the blades 21A, 21B by the spindles 22A, 22B.

[0074] The movement control unit 72 drives the relative movement mechanism 49 including the X drive unit 35 (X carriage 36), the rotation drive unit 38 (rotation unit 37), the Y drive unit 46 (Y carriage 43), and the Z drive unit 48 (Z carriage 44), thereby relatively moving the blades 21A, 21B, and the microscope 23 with respect to the table 31 and the workpiece W.

[0075] For example, before the alignment detection between the workpiece W and the blades 21A, 21B, the movement control unit 72 drives the relative movement mechanism 49 to perform position adjustment of the microscope 23 to a position where the pattern for alignment detection formed on the surface of the workpiece W can be photographed.

[0076] Also, when performing alignment between the workpiece W and the blades 21A, 21B after alignment detection, the movement control unit 72 drives the relative movement mechanism 49 to perform alignment between the blades 21A, 21B and the machining start position of the workpiece W.

[0077] Furthermore, when cutting the workpiece W with the blades 21A, 21B, the movement control unit 72 drives the relative movement mechanism 49 to perform cutting feed of the workpiece W in the X direction, and index feed of the blades 21A, 21B in the Y-axis direction and cutting feed in the Z-axis direction.

[0078] Furthermore, when performing a kerf check after dicing, the movement control unit 72 drives the relative movement mechanism 49 to perform position adjustment of the microscope 23 to a position facing the formation region CR.

[0079] The imaging control unit 74 controls coaxial illumination and imaging of the workpiece W by the microscope 23, and irradiation of infrared light Li onto the workpiece W by the infrared light source 50. At the time of alignment detection, after the position adjustment of the microscope 23 described above, the imaging control unit 74 causes the coaxial illumination unit 52 to perform coaxial illumination and the color imaging element 56b to image the regular reflection light L1A. Thereby, the color camera 56 captures a bright-field image D1 and outputs this bright-field image D1 to the detection unit 76.

[0080] In addition, during the kerf check, the imaging control unit 74 causes the coaxial illumination unit 52 to perform coaxial illumination and the infrared light source 50 to irradiate the workpiece W with infrared light Li after the position adjustment of the microscope 23 as described above, and causes the color imaging device 56b to image the specularly reflected light L1A and the transmitted light LT. As a result, the color camera 56 simultaneously captures the bright-field image D1 and the transmitted image D2, and outputs these bright-field image D1 and transmitted image D2 to the image processing unit 80.

[0081] Based on the bright-field image D1 input from the color camera 56, the detection unit 76 performs alignment detection to detect the position of each street (not shown) of the workpiece W by detecting edge information of the alignment detection pattern of the workpiece W included in the bright-field image D1 by a known image recognition method. Then, the detection unit 76 outputs the alignment detection result to the movement control unit 72. As a result, the movement control unit 72 drives the relative movement mechanism 49 to perform alignment (position matching) between the processing target street C and the blades 21A, 21B.

[0082] After the alignment is completed, the processing control unit 78 drives the spindles 22A, 22B and the relative movement mechanism 49 via the blade drive control unit 70 and the movement control unit 72, and performs dicing processing on each street C of the workpiece W by the step-cut method using the blades 21A, 21B. When the dicing processing is performed, for the kerf check of the first kerf 25A and the second kerf 25B, after the position adjustment of the microscope 23 by the movement control unit 72 and the imaging of the bright-field image D1 and the transmitted image D2 by the color camera 56 by the imaging control unit 74 are executed, the bright-field image D1 and the transmitted image D2 are input from the color camera 56 to the image processing unit 80. In addition, when the kerf check result is input from the measurement unit 82 described later, the processing control unit 78 corrects the positions of the blades 21A, 21B when performing the dicing processing on the next street C.

[0083] FIG. 10 is an explanatory diagram showing an example of the composite image DC generated by the image processing unit 80. As shown in FIG. 10 and the aforementioned FIG. 9, the image processing unit 80 synthesizes the bright-field image D1 and the transmission image D2 input from the color camera 56 to generate the composite image DC. As described above, in the bright-field image D1, the image of the pattern P in the formation region CR and the image of the first kerf 25A (edge portion) become bright enough to be recognizable, but the image of the second kerf 25B (edge portion) becomes dark and unrecognizable. Conversely, in the transmission image D2, the image of the second kerf 25B and the image of the first kerf 25A become bright enough to be recognizable, but the image of the pattern P becomes dark.

[0084] Therefore, the image processing unit 80 detects the image of the second kerf 25B from within the transmission image D2 using a known method such as a pattern matching method, and trims the image of the second kerf 25B (including its peripheral portion) from within the transmission image D2. Here, in the present embodiment, the image of the first kerf 25A is also included in the aforementioned peripheral portion, and the image processing unit 80 trims the images of both the first kerf 25A and the second kerf 25B from within the transmission image D2, but it may also trim only the image of the second kerf 25B. Next, the image processing unit 80 superimposes the trimmed image of the second kerf 25B on the image region of the second kerf 25B that is blacked out in the bright-field image D1. In the present embodiment, the image of the first kerf 25A trimmed from within the transmission image D2 is also superimposed on the image region of the first kerf 25A in the bright-field image D1.

[0085] At this time, since the bright-field image D1 and the transmission image D2 are images taken coaxially by the color camera 56, the position range of the image of the second kerf 25B in the transmission image D2 and the position range of the image of the second kerf 25B in the bright-field image D1 coincide with each other. For this reason, the image processing unit 80 can easily determine the position range of the second kerf 25B that is blacked out in the bright-field image D1 based on the position range of the image of the second kerf 25B in the transmission image D2, and the trimmed image of the second kerf 25B can be accurately superimposed on the image area of the second kerf 25B that is blacked out in the bright-field image D1. As a result, a composite image DC in which the pattern P on the surface of the workpiece W, the edge of the first kerf 25A, and the edge of the second kerf 25B can be recognized respectively is obtained. Then, the image processing unit 80 outputs the composite image DC to the measurement unit 82.

[0086] Based on the composite image DC input from the image processing unit 80, the measurement unit 82 detects, for example, the positions of the first kerf 25A and the second kerf 25B with respect to the pattern P on the surface of the workpiece W. Next, the measurement unit 82 performs a kerf check to detect the amount of positional deviation (Y-direction positional deviation) between the actually measured value and the target value of the position for each of the first kerf 25A and the second kerf 25B. Then, the measurement unit 82 outputs the kerf check result to the processing control unit 78. As a result, based on the kerf check result input from the measurement unit 82, the processing control unit 78 controls the movement control unit 72 to correct the positions (Y-direction positions) of the blades 21A and 21B when dicing the next street C.

[0087] Note that, as the kerf check, the measurement unit 82 may also execute, in addition to the amount of positional deviation of the first kerf 25A and the second kerf 25B, the detection of the width of each of the first kerf 25A and the second kerf 25B and the detection of the processing quality such as the presence or absence of chipping.

[0088] [Operation of the First Embodiment] FIG. 11 is a flowchart showing the flow of dicing processing and kerf check of the work W by the dicing apparatus 10 of the first embodiment having the above configuration. As shown in FIG. 11, when the work W is sucked and held on the table 31, each part of the overall control unit 60 operates. Then, the movement control unit 72 drives the relative movement mechanism 49 to position-adjust the microscope 23 to a position where the alignment detection pattern on the surface of the work W can be photographed (step S1).

[0089] When the position adjustment of the microscope 23 is completed, the imaging control unit 74 starts the emission of the coaxial illumination light L1 from the coaxial illumination light source 52a and the imaging of the specular reflection light L1A by the color imaging element 56b. As a result, a bright-field image D1 including an image of the alignment detection pattern is output from the color camera 56 to the detection unit 76.

[0090] Then, the detection unit 76 performs alignment detection for detecting the position of each street C of the work W by a known method based on the bright-field image D1 input from the color camera 56, and outputs the alignment detection result to the movement control unit 72 (step S2).

[0091] Next, the movement control unit 72 drives the relative movement mechanism 49 based on the alignment detection result by the detection unit 76 to perform alignment between the street C to be processed and the blades 21A, 21B (step S3).

[0092] When the alignment is completed, the processing control unit 78 drives the spindles 22A, 22B and the relative movement mechanism 49 via the blade drive control unit 70 and the movement control unit 72, and performs dicing processing on each street C of the work W by the step-cut method using the blades 21A, 21B (step S4).

[0093] Then, when the dicing processing for one or a plurality of streets C is completed, the kerf check is started. First, the movement control unit 72 drives the relative movement mechanism 49 to position-adjust the microscope 23 to a position where the formed region CR formed on the work W by the dicing processing can be photographed (step S5).

[0094] When the position adjustment of the microscope 23 is completed, the imaging control unit 74 starts the emission of the coaxial illumination light L1 from the coaxial illumination light source 52a and the emission of the infrared light Li from the infrared light source 50, and also starts imaging by the color imaging device 56b. As a result, the coaxial illumination light L1 is irradiated from the front surface side of the workpiece W by the coaxial illumination unit 52 to the formation region CR, and the infrared light Li is irradiated from the back surface side of the workpiece W by the infrared light source 50 to the formation region CR, simultaneously (step S6).

[0095] The mixed light LM of the specular reflection light L1A of the coaxial illumination light L1 specularly reflected in the formation region CR and the transmitted light LT transmitted through the formation region CR enters the color camera 56 through the objective lens 52c and the half mirror 52b, and further enters the color filter array 58 of the color imaging device 56b through the imaging lens 56a.

[0096] The mixed light LM incident on the color filter array 58 is wavelength-separated into the specular reflection light L1A transmitted through each color filter 58R, 58G, 58B and the transmitted light LT transmitted through each color filter 58IR. Then, the specular reflection light L1A is imaged by a plurality of pixels 57 for each color filter 58R, 58G, 58B of the color imaging device 56b. At the same time, the transmitted light LT is imaged by a plurality of pixels 57 for each color filter 58IR of the color imaging device 56b. As a result, the specular reflection light L1A and the transmitted light LT are imaged simultaneously and coaxially in a state where they are separated from each other by the color imaging device 56b (step S7). As a result, the bright-field image D1 obtained by imaging the specular reflection light L1A and the transmitted image D2 obtained by imaging the transmitted light LT are simultaneously output from the color camera 56 to the image processing unit 80.

[0097] Thus, in the present embodiment, when imaging the formation region CR by the microscope 23 from the front surface side of the workpiece W, by irradiating the formation region CR with the infrared light Li from the back surface side of the workpiece W by the infrared light source 50, a bright-field image D1 in which the pattern P and the first kerf 25A can be recognized and a transmitted image D2 in which at least the second kerf 25B can be recognized are obtained.

[0098] When the image processing unit 80 acquires the bright-field image D1 and the transmission image D2 from the color camera 56 (step S8), for example, as described in FIG. 10 above, the image of the second kerf 25B is detected and trimmed from within the transmission image D2. Next, the image processing unit 80 generates a composite image DC by superimposing the trimmed image of the second kerf 25B on the image area of the second kerf 25B that is blacked out in the bright-field image D1, and outputs it to the measurement unit 82 (step S9). As a result, the pattern P on the surface of the workpiece W, the edge of the first kerf 25A, and the edge of the second kerf 25B can be recognized from the composite image DC, so that the positional relationship of the edge of the second kerf 25B with respect to the pattern P becomes clear. Also, the positional relationship of the second kerf 25B with respect to the first kerf 25A becomes clear.

[0099] Furthermore, in the present embodiment, since the bright-field image D1 and the transmission image D2 are coaxially captured by the color camera 56, it is possible to omit the positional deviation correction when synthesizing the image of the second kerf 25B in the transmission image D2 with respect to the bright-field image D1. As a result, the generation of the composite image DC can be performed easily and in a short time.

[0100] Then, based on the composite image DC input from the image processing unit 80, the measurement unit 82 performs a kerf check to detect the amount of positional deviation between the actually measured values and the target values of the positions of the first kerf 25A and the second kerf 25B with respect to the pattern P, and outputs the kerf check result to the processing control unit 78 (step S10). At this time, since the positional relationship of the edge of the second kerf 25B with respect to the pattern P and the positional relationship of the second kerf 25B with respect to the first kerf 25A can be clearly recognized based on the composite image DC, it is possible to perform the kerf check with higher accuracy than before, particularly for the second kerf 25B with a deeper processing depth.

[0101] Based on the kerf check result input from the measurement unit 82, the processing control unit 78 controls the movement control unit 72 to correct the positions of the blades 21A and 21B when dicing the next street C (step S11). As a result, the first kerf 25A and the second kerf 25B can be formed with high precision along the subsequent streets C. In particular, in the present embodiment, since the kerf check for the second kerf 25B can be performed with higher precision than in the prior art, the processing accuracy of the second kerf 25B can be improved.

[0102] As described above, in the first embodiment, the irradiation of the coaxial illumination light L1 to the formation region CR by the coaxial illumination unit 52 and the irradiation of the infrared light Li to the formation region CR by the infrared light source 50 are executed simultaneously, and the color camera 56 wavelength-separates and images the regular reflection light L1A and the transmitted light LT, so that a bright-field image D1 in which the pattern P and the first kerf 25A can be recognized and a transmitted image D2 in which the second kerf 25B can be recognized are obtained. As a result, based on the bright-field image D1 and the transmitted image D2, the first kerf 25A and the second kerf 25B can be recognized better at a lower cost and in a shorter time than in the prior art without using a microscope 23 with a large NA or a white interferometer.

[0103] [Second Embodiment] FIG. 12 is a block diagram of the dicing apparatus 10 according to the second embodiment. FIG. 13 is a side view of the microscope 23 according to the second embodiment. In the first embodiment described above, the color imaging element 56b of the color camera 56 wavelength-separates and images the regular reflection light L1A and the transmitted light LT, but in the second embodiment, the regular reflection light L1A and the transmitted light LT are wavelength-separated and imaged without using the color imaging element 56b.

[0104] As shown in FIGS. 12 and 13, the dicing apparatus 10 of the second embodiment is basically the same as that of the first embodiment, except that a half mirror 52d, a transmission filter 52e, and a transmission filter 52f are provided in the microscope 23, and a first camera 59A and a second camera 59B are provided instead of the color camera 56. Therefore, the same reference numerals are given to those having the same functions or configurations as those in the first embodiment, and the description thereof is omitted. In the second embodiment, the imaging unit of the present invention is constituted by the half mirror 52d, the transmission filter 52e, the transmission filter 52f, the first camera 59A, and the second camera 59B.

[0105] The half mirror 52d corresponds to the light separation element of the present invention and is disposed above the half mirror 52b in the Z direction. This half mirror 52d transmits a part of the mixed light LM (corresponding to the first light of the present invention) incident from the half mirror 52b upward in the Z direction, and reflects the remainder of the mixed light LM (corresponding to the second light of the present invention) laterally, here in the X direction. Note that various light separation elements other than the half mirror 52d may be used as long as the mixed light LM can be split into two.

[0106] The transmission filter 52e (corresponding to the first filter of the present invention) is disposed at a position above the half mirror 52b in the Z direction and on the optical path of the mixed light LM, and is a band-pass filter that transmits only light in the wavelength range of the specularly reflected light L1A (coaxial illumination light L1). Thereby, when the mixed light LM is incident from the half mirror 52d, the transmission filter 52e transmits only the specularly reflected light L1A and emits it toward the first camera 59A described later.

[0107] The transmission filter 52f (corresponding to the second filter of the present invention) is disposed laterally of the half mirror 52b (on the reflection direction side of the mixed light LM) and on the optical path of the mixed light LM, and is a band-pass filter that transmits only light in the wavelength range of the transmitted light LT (infrared light Li). Thereby, when the mixed light LM is incident from the half mirror 52d, the transmission filter 52f transmits only the transmitted light LT and emits it toward the second camera 59B described later.

[0108] The first camera 59A is disposed above the transmission filter 52e in the Z direction. The first camera 59A is a so-called monochrome camera and includes a first imaging lens 90a and a first image sensor 92a that does not have a color filter array 58.

[0109] The first imaging lens 90a forms an image of the specularly reflected light L1A transmitted through the transmission filter 52e on the light-receiving surface of the first image sensor 92a. Thereby, the first image sensor 92a captures only the specularly reflected light L1A and outputs a bright-field image D1 to the overall control unit 60. At this time, unlike the color image sensor 56b of the first embodiment, the first image sensor 92a uses all the pixels 57 within the light-receiving surface (within the effective region) to capture the specularly reflected light L1A, so a bright-field image D1 with higher resolution than that of the first embodiment can be obtained. Note that the transmission filter 52e may be provided on the light-receiving surface of the first image sensor 92a. In this case, the first camera 59A becomes a camera sensitive to the specularly reflected light L1A.

[0110] The second camera 59B is disposed at a position facing the exit surface of the transmission filter 52f and includes a second imaging lens 90b and a second image sensor 92b that does not have a color filter array 58. The second imaging lens 90b forms an image of the transmitted light LT transmitted through the transmission filter 52f on the light-receiving surface of the second image sensor 92b. Thereby, the second image sensor 92b captures only the transmitted light LT and outputs a transmitted image D2 to the overall control unit 60. At this time, the second image sensor 92b can also use all the pixels 57 within the light-receiving surface to capture the transmitted light LT, so a transmitted image D2 with higher resolution than that of the first embodiment can be obtained. Note that the transmission filter 52f may also be provided on the light-receiving surface of the second image sensor 92b. In this case, the second camera 59B becomes a camera sensitive to the transmitted light LT.

[0111] In the second embodiment, the imaging control unit 74 causes the coaxial illumination unit 52 to perform coaxial illumination, and the first imaging device 92a to image the specular reflection light L1A during alignment detection. As a result, the first camera 59A captures the bright-field image D1 and outputs the bright-field image D1 to the detection unit 76. As a result, similar to the first embodiment, alignment detection by the detection unit 76 and alignment by the movement control unit 72 are performed.

[0112] Further, during the curl check, the imaging control unit 74 causes the coaxial illumination unit 52 to perform coaxial illumination, the infrared light source 50 to irradiate the workpiece W with infrared light Li, the first imaging device 92a to image the specular reflection light L1A, and the second imaging device 92b to image the transmitted light LT. As a result, after the first camera 59A captures the bright-field image D1 and the second camera 59B captures the transmitted image D2 simultaneously, the bright-field image D1 and the transmitted image D2 are output from the first camera 59A and the second camera 59B to the image processing unit 80. As a result, similar to the first embodiment, generation of the composite image DC by the image processing unit 80, curl check by the measurement unit 82, and correction of the processing position by the processing control unit 78 are performed.

[0113] As described above, in the second embodiment, by combining the half mirror 52d, the transmission filters 52e and 52f, the first camera 59A, and the second camera 59B, the specular reflection light L1A and the transmitted light LT can be easily wavelength-separated and imaged simultaneously, similar to the first embodiment. As a result, the same effect as the first embodiment is obtained. Further, by using the first camera 59A and the second camera 59B (monochrome cameras), bright-field images D1 and transmitted images D2 with higher resolution than the first embodiment can be obtained, so that the accuracy of the curl check of the first curl 25A and the second curl 25B (especially the second curl 25B) can be further improved.

[0114] [Modification Example of the Second Embodiment] FIG. 14 is a side view of a modified example of the microscope 23 according to the second embodiment. In the above-described second embodiment, the mixed light LM is wavelength-separated into the specular reflection light L1A and the transmitted light LT using the half mirror 52d and the transmission filters 52e and 52f. However, as shown in FIG. 14, the above-described wavelength separation may be performed using a dichroic mirror 52g (corresponding to the wavelength separation element of the present invention). In this case, the imaging unit of the present invention is configured by the dichroic mirror 52g, the first camera 59A, and the second camera 59B.

[0115] Note that various wavelength separation elements other than the dichroic mirror 52g may be used as long as the mixed light LM can be wavelength-separated into the specular reflection light L1A and the transmitted light LT.

[0116] As described above, in the modified example of the second embodiment, by wavelength-separating the mixed light LM into the specular reflection light L1A and the transmitted light LT using the dichroic mirror 52g, the number of components of the microscope 23 can be reduced compared to the second embodiment, so that the microscope 23 can be miniaturized and the cost can be reduced.

[0117] [Third Embodiment] FIG. 15 is a side view of the microscope 23 of the dicing apparatus 10 according to the third embodiment. The microscope 23 of each of the above embodiments performs coaxial illumination for irradiating the surface (formation region CR, etc.) of the workpiece W with coaxial illumination light L1. However, the microscope 23 of the third embodiment simultaneously performs coaxial illumination and oblique illumination (also referred to as inclined illumination) on the surface of the workpiece W.

[0118] Note that the dicing apparatus 10 according to the third embodiment has basically the same configuration as the dicing apparatus 10 according to the first embodiment, except that the coaxial illumination unit 52 (coaxial illumination light source 52a) emits light in a specific wavelength range λA (for example, red light) in white light (visible light) as the coaxial illumination light L1 and includes a ring illumination unit 54.

[0119] The ring illumination unit 54 corresponds to the oblique illumination unit of the present invention. This ring illumination unit 54 has light sources 54a such as a plurality of LEDs arranged at equal angular pitches along the circumferential direction centered on its optical axis O1 so as to surround the objective lens 52c, for example. Each light source 54a performs oblique illumination that irradiates oblique illumination light L2 from an oblique direction onto the surface of the workpiece W and the workpiece holding surface 31a. As this oblique illumination light L2, light in a wavelength range λB different from the wavelength range λA in visible light, for example, blue light, is used. When the oblique illumination light L2 is irradiated onto the surface of the workpiece W from an oblique direction, the oblique illumination light L2 is scattered on this surface, and a part of the scattered light L2A passes through the objective lens 52c, further passes through the half mirror 52b, and enters the color camera 56.

[0120] The overall control unit 60 of the third embodiment causes the coaxial illumination unit 52 to irradiate the surface of the workpiece W with the coaxial illumination light L1, the ring illumination unit 54 to irradiate the surface of the workpiece W with the oblique illumination light L2, and the infrared light source 50 to irradiate the back surface side of the workpiece W with the infrared light Li, all at the same time. As a result, mixed light LM of the specular reflection light L1A, the scattered light L2A, and the transmitted light LT enters the color camera 56 of the third embodiment. Incidentally, if necessary, it is also possible to selectively perform the irradiation of the coaxial illumination light L1 onto the surface of the workpiece W by the coaxial illumination unit 52 and the irradiation of the oblique illumination light L2 onto the surface of the workpiece W by the ring illumination unit 54.

[0121] The color camera 56 of the third embodiment wavelength-separates the mixed light LM that has entered through the half mirror 52b into the specular reflection light L1A, the scattered light L2A, and the transmitted light LT, and then simultaneously images the specular reflection light L1A, the scattered light L2A, and the transmitted light LT.

[0122] Specifically, in the third embodiment, the mixed light LM incident on the color filter array 58 is wavelength-separated into the specular reflection light L1A transmitted through each color filter 58R, the scattered light L2A transmitted through each color filter 58B, and the transmitted light LT transmitted through each color filter 58IR. As a result, the specular reflection light L1A is imaged by a plurality of pixels 57 for each color filter 58R of the color image sensor 56b, the scattered light L2A is imaged by a plurality of pixels 57 for each color filter 58B, and the transmitted light LT is imaged by a plurality of pixels 57 for each color filter 58IR.

[0123] Thus, in the third embodiment, the color image sensor 56b simultaneously images the specular reflection light L1A, the scattered light L2A, and the transmitted light LT in a state where they are separated from each other. As a result, similar to the above-described embodiments, a bright-field image D1 and a transmitted image D2 are obtained, and a dark-field image (not shown, the same applies hereinafter) of the surface of the workpiece W is obtained by imaging the scattered light L2A only with a plurality of pixels 57 for the color filter 58B. Therefore, the color camera 56 can simultaneously and coaxially image the bright-field image D1, the transmitted image D2, and the dark-field image.

[0124] The imaging control unit 74 of the third embodiment causes the coaxial illumination unit 52 to perform coaxial illumination, the ring illumination unit 54 to perform oblique illumination, and the color image sensor 56b to image the specular reflection light L1A and the scattered light L2A during the above-described alignment detection. As a result, the color camera 56 captures the bright-field image D1 and the dark-field image, and outputs these bright-field image D1 and dark-field image to the detection unit 76.

[0125] Also, the imaging control unit 74 of the third embodiment causes the coaxial illumination unit 52 to perform coaxial illumination, the ring illumination unit 54 to perform oblique illumination, the infrared light source 50 to irradiate the workpiece W with infrared light Li, and the color image sensor 56b to image the specular reflection light L1A, the scattered light L2A, and the transmitted light LT during the above-described kerf check. As a result, the color camera 56 simultaneously captures the bright-field image D1, the transmitted image D2, and the dark-field image, and outputs these bright-field image D1, transmitted image D2, and dark-field image to the image processing unit 80.

[0126] The detection unit 76 of the third embodiment performs the above-described alignment detection based on the bright-field image D1 and the dark-field image input from the color camera 56. Here, on the surface of the workpiece W, both a pattern that is easier to recognize in the bright-field image D1 by coaxial illumination and a pattern that is easier to recognize in the dark-field image by oblique illumination are included. Therefore, in the third embodiment, it is possible to recognize a pattern that is difficult to recognize only with the bright-field image D1 based on the dark-field image. As a result, the detection unit 76 of the third embodiment can improve the accuracy of alignment detection compared to each of the above embodiments.

[0127] The image processing unit 80 of the third embodiment synthesizes the bright-field image D1, the transmission image D2, and the dark-field image input from the color camera 56 to generate a composite image DC. Here, the dark-field image is obtained by imaging at least a part of the scattered light L2A scattered at the bottom of the first kerf 25A by the color imaging element 56b. Therefore, in the dark-field image, the image of the first kerf 25A (edge portion) in the formation region CR becomes easier to recognize than the bright-field image D1. Therefore, the image processing unit 80 trims the image of the first kerf 25A (including its peripheral portion) from the dark-field image. Next, the image processing unit 80 superimposes the trimmed image of the first kerf 25A on the image region of the first kerf 25A in the bright-field image D1. Thereby, the positional relationship of the edge of the first kerf 25A with respect to the pattern P becomes clearer than in each of the above embodiments.

[0128] Also, the image processing unit 80 of the third embodiment trims the image of the second kerf 25B from the transmission image D2 and superimposes the trimmed image of the second kerf 25B on the image region of the second kerf 25B in the bright-field image D1, in the same manner as in each of the above embodiments. Thereby, the generation of the composite image DC by the image processing unit 80 is completed. Also in this case, since the bright-field image D1, the transmission image D2, and the dark-field image are coaxially photographed by the color camera 56, it is possible to omit the positional deviation correction when synthesizing these images, and as a result, the composite image DC can be generated easily and in a short time.

[0129] Similar to the above embodiments, the measurement unit 82 of the third embodiment performs a curvature check of the first curvature 25A and the second curvature 25B with respect to the pattern P based on the composite image DC input from the image processing unit 80. At this time, in the composite image DC of the third embodiment, the positional relationship of the edge of the first curvature 25A with respect to the pattern P becomes clearer, so the measurement unit 82 can perform a curvature check of the first curvature 25A with higher accuracy than in the above embodiments.

[0130] In addition, also in the second embodiment and its modification, it is also possible to perform oblique light illumination and acquisition of a dark field image at the time of alignment detection and curvature check. In this case, for the second embodiment and its modification, a configuration for wavelength-separating the mixed light LM into the specularly reflected light L1A, the scattered light L2A, and the transmitted light LT (a combination of a half mirror and a transmission filter, a dichroic mirror, etc.), and a third camera (not shown) for imaging the scattered light L2A are added.

[0131] Also, in the third embodiment, the ring illumination unit 54 performs oblique light illumination on the workpiece W, but various oblique light illumination units capable of oblique light illumination may be used instead of the ring illumination unit 54.

[0132] Furthermore, in the third embodiment, red light is used as the coaxial illumination light L1 and blue light (short wavelength and easily scattered on the surface of the workpiece W) is used as the oblique illumination light L2, but blue light may be used as the coaxial illumination light L1 and red light may be used as the oblique illumination light L2. That is, the wavelength range λA of the coaxial illumination light L1 and the wavelength range λB of the oblique illumination light L2 are not particularly limited as long as they are different from each other. Furthermore, the wavelength range λA and the wavelength range λB are not limited to the visible wavelength range as long as they are different from the wavelength range of the infrared light Li, and may be, for example, the infrared wavelength range.

[0133] In the previous embodiments, the case of generating the composite image DC by synthesizing the bright-field image D1 and the transmission image D2 has been described. However, the bright-field image D1 and the transmission image D2 are images obtained by coaxial imaging of the microscope 23. Therefore, if the positional relationship between the second curve 25B with respect to the first curve 25A becomes clear based on the positional relationship between the image of the first curve 25A in the bright-field image D1 and the image of the second curve 25B in the transmission image D2, it is not always necessary to synthesize the bright-field image D1 and the transmission image D2. In this case, the measurement unit 82 performs a curve check based on the bright-field image D1 and the transmission image D2.

[0134] [Other Modification Examples of Microscope] FIG. 16 is a side view showing an example of a microscope 110 of a dicing apparatus 10 that images the specularly reflected light L1A and the scattered light L2A in a time-division manner. The microscope 23 of each of the above embodiments simultaneously images the specularly reflected light L1A and the transmitted light LT (including the scattered light L2A in the third embodiment), but as in the microscope 110 shown in FIG. 16, the specularly reflected light L1A and the transmitted light LT may be imaged in a time-division manner.

[0135] The microscope 110 has basically the same configuration as the microscope 23 (see FIG. 13) of the second embodiment described above, except that it includes a filter switching mechanism 111 instead of the half mirror 52d, the transmission filter 52e, the transmission filter 52f, and the second camera 59B. Therefore, those that are the same as those in the second embodiment in terms of function or configuration are denoted by the same reference numerals and their description is omitted.

[0136] The filter switching mechanism 111 is disposed between the half mirror 52b and the first camera 59A. Under the control of the overall control unit 60, the filter switching mechanism 111 selectively arranges the transmission filter 112A and the transmission filter 112B on the optical path of the mixed light LM.

[0137] The transmission filter 112A is basically the same as the transmission filter 52e of the second embodiment, and transmits only light in the wavelength range of the specularly reflected light L1A (coaxial illumination light L1). Thus, when the transmission filter 112A is disposed on the optical path of the mixed light LM, only the specularly reflected light L1A enters the first camera 59A. As a result, a bright-field image D1 is output from the first camera 59A to the overall control unit 60.

[0138] The transmission filter 112B is basically the same as the transmission filter 52f of the second embodiment, and transmits only light in the wavelength range of the transmitted light LT (infrared light Li). Thus, when the transmission filter 112B is disposed on the optical path of the mixed light LM, only the transmitted light LT enters the first camera 59A. As a result, a transmitted image D2 is output from the first camera 59A to the overall control unit 60.

[0139] As described above, by driving the filter switching mechanism 111 to sequentially dispose the transmission filter 112A and the transmission filter 112B on the optical path of the mixed light LM, the first camera 59A can capture the specularly reflected light L1A and the transmitted light LT in a time-division manner. Also in this case, based on the bright-field image D1 and the transmitted image D2 captured by the first camera 59A, alignment detection, kerf check, etc. can be executed in the same manner as in the above embodiments.

[0140] When the color imaging device 56b of the microscope 23 of the first embodiment is of the CMOS type, by controlling the color imaging device 56b, imaging of the specularly reflected light L1A by a plurality of pixels 57 corresponding to the color filters 58R, 58G, 58B and imaging of the transmitted light LT by a plurality of pixels 57 corresponding to the color filters 58IR can be performed in a time-division manner.

[0141] Also, when imaging the scattered light L2A as in the third embodiment, a transmission filter (not shown) that transmits only light in the wavelength range λB corresponding to the scattered light L2A may be added to the filter switching mechanism 111.

[0142] [Others] In each of the above embodiments, the infrared light Li is irradiated from the back side of the workpiece W. However, as the second illumination light of the present invention, light in a wavelength range that can pass through the workpiece W and is different from the coaxial illumination light L1 (including the oblique illumination light L2) may be light other than the infrared light Li (including visible light).

[0143] In each of the above embodiments, the infrared light source 50 is provided inside the table 31. However, the infrared light source 50 may be provided separately from the table 31.

[0144] In each of the above embodiments, the case of performing the kerf check of the first kerf 25A and the second kerf 25B formed by the step cut type dicing process has been described as an example. However, the present invention can also be applied to the case of performing the kerf check of the kerf formed by the meeting cut type dicing process, and it is particularly effective for the kerf check of a kerf with a deep processing depth. Furthermore, instead of performing the dicing process using the two blades 21A and 21B, the present invention can also be applied to the kerf check of the kerf formed using one or three or more blades.

[0145] In each of the above embodiments, the dicing tape T is adhered to the back surface of the workpiece W, and the workpiece holding surface 31a sucks and holds the workpiece W via the dicing tape T. However, the workpiece holding surface 31a may directly suck and hold the back surface side of the workpiece W.

[0146] In each of the above embodiments, the dicing apparatus 10 and its microscope 23 that perform the dicing process of the workpiece W using the blades 21A and 21B have been described as an example. However, the present invention can also be applied to a laser processing apparatus (corresponding to a dicing apparatus) that performs laser grooving along the street C of the wafer using laser light.

Explanation of Reference Numerals

[0147] 10 Dicing apparatus 10A Housing 12 Load port 14 Conveying mechanism 16 Processing section 18 Cleaning section 21A, 21B Blades 22A, 22B Spindles 23 Microscope 31 Table 31a Workholding surface 32 X - base 34 X - guide 35 X - drive unit 36 X - carriage 37 Rotation unit 38 Rotation drive unit 41 Y - base 42 Y - guide 43 Y - carriage 44 Z - carriage 46 Y - drive unit 48 Z - drive unit 49 Relative movement mechanism 50 Infrared light source 52 Coaxial illumination section 52a Coaxial illumination light source 52b Half - mirror 52c Objective lens 52d Half - mirror 52e Transmission filter 52f Transmission filter 52g Dichroic mirror 54 Ring illumination section 54a Light source 56 Color camera 56a Imaging lens 56b Color imaging element 57 Pixel 58 Color filter array 58B Color filter 58G Color filter 58R Color filter 58IR Color filter 59A First camera 59B Second camera 60 Integrated control unit 62 Operation section 64 Memory section 66 Display section 70 Blade Drive Control Unit 72 Movement Control Unit 74 Shooting Control Unit 76 Detection Unit 78 Processing Control Unit 80 Image Processing Unit 82 Measurement Unit 90a First Imaging Lens 90b Second Imaging Lens 92a First Image Sensor 92b Second Image Sensor 110 Microscope 111 Filter Switching Mechanism 112A, 112B Transmission Filters C Street CA Rotation Axis D1 Bright-Field Image D2 Transmission Image DC Composite Image F Frame L1 Coaxial Illumination Light L1A Regular Reflection Light L2 Oblique Illumination Light L2A Scattered Light Li Infrared Light LT Transmission Light LM Mixed Light O1 Optical Axis W Workpiece λA Wavelength Range λB Wavelength Range

Claims

1. In a kerf imaging device that images a kerf formed along a street of a workpiece from the surface side of the workpiece, a first illumination unit that irradiates a first illumination light to a formation region of the kerf from the surface side of the workpiece; a second illumination unit that irradiates a second illumination light in an infrared wavelength region different from the wavelength region of the first illumination light to the formation region from the back side of the workpiece; an imaging unit that receives a mixed light of the reflected light of the first illumination light reflected in the formation region and the transmitted light of the second illumination light that passes through the formation region from the back side of the workpiece and exits from the surface side of the workpiece, and that separates the mixed light into the reflected light and the transmitted light and simultaneously images them; A kerf imaging device comprising the above.

2. The imaging unit is a color imaging device including a plurality of pixels arranged in a two-dimensional array and a plurality of color filters disposed on the plurality of pixels, The plurality of color filters include a plurality of first color filters that transmit only the first illumination light and a plurality of second color filters that transmit only the second illumination light. The kerf imaging device according to claim 1.

3. The imaging unit an optical separation element that separates the mixed light into first light and second light; a first filter disposed on the optical path of the first light separated by the optical separation element and transmitting only the reflected light; a first imaging element that images the reflected light transmitted through the first filter; a second filter disposed on the optical path of the second light separated by the optical separation element and transmitting only the transmitted light; a second imaging element that images the transmitted light transmitted through the second filter; The kerf imaging device according to claim 1, comprising the above.

4. The imaging unit a wavelength separation element that wavelength-separates the mixed light into the reflected light and the transmitted light; a first imaging element that images the reflected light wavelength-separated by the wavelength separation element; a second imaging element that images the transmitted light wavelength-separated by the wavelength separation element; The kerf imaging device according to claim 1, comprising the above.

5. Comprising a table that holds the workpiece from the back side of the workpiece, The kerf imaging device according to any one of claims 1 to 4, wherein the second illumination unit is provided on the table.

6. The kerf imaging device according to any one of claims 1 to 5, wherein the first illumination unit irradiates the formation region with coaxial illumination light as the first illumination light.

7. The first illumination unit irradiates the forming region with coaxial illumination light as the first illumination light and irradiates the forming region with oblique illumination light having a wavelength range different from that of the coaxial illumination light from an oblique direction, The reflected light includes specular reflection light of the coaxial illumination light specularly reflected by the forming region and scattered light of the oblique illumination light scattered by the forming region, The imaging device according to any one of claims 1 to 5, wherein the imaging unit separates and simultaneously images the specular reflection light and the scattered light.

8. When the kerf includes a first kerf formed on the surface side of the workpiece and a second kerf formed at the bottom of the first kerf, the imaging unit images the reflected light to form an image of a pattern formed on the surface of the workpiece and an image of the first kerf. A kerf imaging device according to any one of claims 1 to 7, which generates a first captured image including the image, and images the transmitted light to generate a second captured image including an image of the second kerf.

9. The kerf imaging device according to claim 8, further comprising an image processing unit that synthesizes an image of the second kerf in the second captured image with the first captured image to generate a synthesized image.

10. In a dicing device that forms a kerf along a street of a workpiece from the surface side of the workpiece, A dicing device comprising the kerf imaging device according to any one of claims 1 to 9.

Images