JP7699328B2 - Kerf photography equipment and dicing equipment - Google Patents

Description

The present invention relates to a kerf imaging device and a dicing device that photographs kerfs formed along the streets of a workpiece.

There is known a dicing device that uses a disk-shaped blade rotated at high speed by a spindle to dice (cut) a workpiece such as a silicon wafer (see Patent Document 1). This dicing device performs dicing by moving a blade that rotates at high speed along streets (also called planned division lines) formed in a grid pattern on the workpiece, thereby forming kerfs (grooves) along the streets. Another known dicing device is a twin-spindle dicer that has two spindles on which the blades are attached. Two known methods for cutting or slicing a workpiece with this twin-spindle dicer are the meeting cutting method and the step cut method.

The meeting cutting method is a method in which two streets are cut at once using two blades. The step cut method is a method in which the first blade cuts a first kerf of a specified depth along the street, and then the second blade dices the bottom of the first kerf to form a second kerf, thereby cutting the workpiece along the street.

The blades of such dicing machines wear down with use, which can cause chipping on the surface of the workpiece cut by the blade. In addition, due to the influence of thermal deformation of the blade, the position of the kerf formed in the workpiece by the blade can shift from the center of the street. For this reason, dicing machines check the kerf of the blade at preset times.

For example, in the dicing device described in Patent Document 1, the kerf formed in the workpiece is illuminated by a microscope using coaxial lighting and oblique lighting from an oblique direction while being photographed, and a kerf check is performed to measure the kerf position (position deviation from the target value) based on the image captured by the microscope.

The dicing device described in Patent Document 2 above is equipped with a white interferometer that emits white light toward a kerf formation area (machining area) formed on the workpiece and detects an interference signal between the white light reflected from this machining area and the white light reflected on a reference surface. This dicing device vertically scans the white interferometer in the Z-axis direction and acquires interference signals output from each pixel (pixels of the imaging element that captures the interference signal) of the white interferometer at each position in the Z-axis direction. The dicing device then performs a kerf check by generating a three-dimensional image of the machining area based on the interference signal for each pixel.

JP 2011-165826 A JP 2021-84201 A

Figure 17 is an explanatory diagram for explaining the problems that arise when performing a kerf check based on an image of the kerf photographed by a microscope. In this example, a first kerf 25A and a second kerf 25B are formed in the workpiece W by the step cut method, and a dicing tape T is attached to the back surface of the workpiece W.

In the dicing device described in the above Patent Document 1, the kerf is photographed by a microscope, but as shown in FIG. 17, the processing depth of the kerf (first kerf 25A, second kerf 25B) formed by the above-mentioned step cut method is deep. 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. In addition, the bottom of the second kerf 25B does not easily reflect 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 image captured by the microscope, the images of the first kerf 25A and the second kerf 25B are dark, and since there is no difference in brightness especially at the edge of the second kerf 25B, it is difficult to detect the position of the second kerf 25B.

It is therefore conceivable to perform an overtaking kerf check in which an uncut portion of the workpiece W is cut with a first blade, another uncut portion of the workpiece W is cut with a second blade, and the kerf of each blade is checked based on images of the two kerfs formed by each blade photographed with a microscope. However, with the overtaking kerf check, it is not possible to recognize the positional relationship between the first kerf 25A formed by the first blade and the second kerf 25B formed by the second blade.

It is also possible to use a microscope with a large NA (Numerical Aperture), but in this case the focal depth of the microscope will be shallow. For this reason, if the focal position of the microscope is not changed when photographing the pattern on the surface of the workpiece W and each of the kerfs 25A, 25B, the image of either the pattern or each of the kerfs 25A, 25B will be unclear.

Furthermore, when performing a kerf check using a white light interferometer as in the dicing device described in Patent Document 2, a vertical scanning mechanism for the white light interferometer is required, and a large amount of interference signal must be analyzed, which creates problems of cost and time.

The present invention was made in consideration of these circumstances, and aims to provide a kerf imaging device and a dicing device that can clearly recognize kerfs at low cost and in a short time.

The kerf photographing device for achieving the object of the present invention is a kerf photographing device for photographing a kerf formed along the street of a workpiece from the surface side of the workpiece, and is equipped with a first illumination unit that irradiates a first illumination light from the surface side of the workpiece onto the kerf formation area, a second illumination unit that irradiates a second illumination light of an infrared wavelength range different from the wavelength range of the first illumination light onto the formation area from the back side of the workpiece, and an imaging unit into which a mixed light of the reflected light of the first illumination light reflected at the formation area and the transmitted light of the second illumination light that passes through the formation area from the back side of the workpiece and is emitted from the surface side of the workpiece is incident, and which separates the mixed light into reflected light and transmitted light and simultaneously images them.

This microscope can recognize the pattern on the workpiece surface based on the image obtained by capturing reflected light, and can recognize kerf edge information based on the image obtained by capturing transmitted light.

In another aspect of the calf imaging device of the present invention, the imaging unit is a color imaging element having a plurality of pixels arranged two-dimensionally and a plurality of color filters arranged on the plurality of pixels, and 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. This allows the mixed light to be separated into reflected light and transmitted light and imaged simultaneously and coaxially.

In a calf imaging device according to another aspect of the present invention, the imaging unit includes a light separation element that separates the mixed light into a first light and a second light, a first filter that is arranged on the optical path of the first light separated by the light separation element and transmits only reflected light, a first imaging element that images the reflected light that has passed through the first filter, a second filter that is arranged on the optical path of the second light separated by the light separation element and transmits only transmitted light, and a second imaging element that images the transmitted light that has passed through the second filter. This allows the mixed light to be separated into the reflected light and the transmitted light and imaged simultaneously and coaxially, resulting in an even higher resolution image.

In a calf imaging device according to another aspect of the present invention, the imaging unit includes a wavelength separation element that separates mixed light into reflected light and transmitted light, a first imaging element that images the reflected light that has been wavelength-separated by the wavelength separation element, and a second imaging element that images the transmitted light that has been wavelength-separated by the wavelength separation element. This allows the mixed light to be separated into reflected light and transmitted light and imaged simultaneously and coaxially, resulting in a higher-resolution image. In addition, the number of components in the microscope can be reduced, which allows the microscope to be made smaller and less expensive.

In another aspect of the present invention, a kerf imaging device is provided with a table that holds the workpiece from the back side of the workpiece, and a second illumination unit is provided on the table.

In another aspect of the present invention, in a kerf imaging device, the first illumination unit irradiates the formation area with coaxial illumination light as the first illumination light. This allows a bright-field image of the formation area to be obtained.

In a kerf imaging device according to another aspect of the present invention, the first illumination unit irradiates the formation area with coaxial illumination light as the first illumination light, and also irradiates the formation area with oblique illumination light having a wavelength range different from that of the coaxial illumination light from an oblique direction, and the reflected light includes specularly reflected light of the coaxial illumination light that is specularly reflected at the formation area, and scattered light of the oblique illumination light that is scattered at the formation area, and the imaging unit separates the specularly reflected light and the scattered light and simultaneously images them. This makes it possible to obtain bright-field and dark-field images of the formation area, making it possible to recognize patterns that are difficult to recognize using only bright-field images, and also making it easier to recognize the kerf.

In a kerf photographing 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 captures 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 captures transmitted light to generate a second captured image including an image of the second kerf. This makes it possible to recognize all of the pattern on the surface of the workpiece, the first kerf, and the second kerf with a deep machining depth.

In another aspect of the present invention, the kerf imaging device includes an image processing unit that generates a composite image by combining the image of the second kerf in the second captured image with the first captured image. This makes it possible to recognize the pattern on the surface of the workpiece, the first kerf, and the second kerf with a deep machining depth.

The dicing device for achieving the object of the present invention is a dicing device that forms kerfs along the streets of a workpiece from the surface side of the workpiece, and is equipped with the above-mentioned kerf imaging device.

The present invention allows for good recognition of kerfs at low cost and in a short time.

1 is a perspective view of a dicing device according to a first embodiment; FIG. FIG. 13 is an explanatory diagram for explaining a step cut method. FIG. 2 is a schematic diagram of an infrared light source provided on a table. FIG. 2 is a side view of the microscope according to the first embodiment, illustrating a state during a kerf check. 2 is an enlarged view of a color filter array provided on the light receiving surface of the color imaging element. FIG. 2 is an explanatory diagram showing an example of a bright-field image captured by a color camera. FIG. 2 is an explanatory diagram showing an example of a transmission image captured by a color camera. 2 is a functional block diagram of a general control unit of the dicing device of the first embodiment. FIG. FIG. 4 is an explanatory diagram showing an example of a composite image generated by an image processing unit. 5 is a flowchart showing a flow of a dicing process and a car check of a workpiece by the dicing device of the first embodiment. FIG. 11 is a block diagram of a dicing device according to a second embodiment. FIG. 11 is a side view of a microscope according to a second embodiment. FIG. 13 is a side view of a modified example of the microscope of the second embodiment. FIG. 13 is a side view of a microscope of the dicing apparatus of the third embodiment. FIG. 1 is a side view showing an example of a microscope of a dicing device that captures images of specularly reflected light and scattered light in a time-division manner. FIG. 1 is an explanatory diagram for explaining a problem that occurs when performing a kerf check based on an image of the kerf photographed by a microscope.

[First embodiment]
1 is a perspective view of a dicing apparatus 10 according to a first embodiment. Note that the X, Y and Z axes in the figure are mutually perpendicular, the X and Y axes are parallel to the horizontal direction, and the Z axis is perpendicular to the horizontal direction.

As shown in FIG. 1, the dicing device 10 is equipped with the kerf imaging device of the present invention (microscope 23 and infrared light source 50 in FIG. 5, etc.), and dices a flat workpiece W such as a silicon wafer (semiconductor wafer). This dicing device 10 is equipped with a load port 12, a transport mechanism 14, a processing section 16, and a cleaning section 18.

A cassette containing a large number of workpieces W mounted on a frame F is placed on the load port 12. The transport mechanism 14 transports the workpieces W. The processing unit 16 dices the workpieces W. The cleaning unit 18 spin-cleans the diced workpieces W. Inside the housing 10A of the dicing device 10, there is provided a general control unit 60 (see FIG. 9) that controls the operation of each part of the dicing device 10. The general control unit 60 may be provided outside the housing 10A.

The unmachined workpiece W stored in a cassette placed on the load port 12 is transported by the transport mechanism 14 to the processing section 16, where it is cut or diced, such as by grooving, to separate it into individual chips. The workpiece W that has been processed by the processing section 16 is then transported by the transport mechanism 14 to the cleaning section 18, where it is cleaned, and then transported by the transport mechanism 14 to the load port 12 and stored in a cassette.

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

Blades 21A and 21B are formed in a disk shape. The tip shape of blades 21A and 21B, i.e., the cross-sectional shape of the outer periphery (cutting edge) of blades 21A and 21B along the radial direction of blades 21A and 21B, is rectangular (other shapes such as V-shape are also acceptable). Blades 21A and 21B are arranged opposite each other in the Y-axis direction, and are held by spindles 22A and 22B so as to be rotatable about blade rotation axes parallel to the Y-axis direction.

The spindles 22A and 22B incorporate high-frequency motors and rotate the blades 21A and 21B at high speed around the blade rotation axis. This causes the blades 21A and 21B to dicing the workpiece W from its front surface (device forming surface). A kerf (groove) is formed in the workpiece W by dicing the workpiece W with the blades 21A and 21B.

The microscope 23 is mounted on the Z carriage 44 integrally with the spindle 22A (or spindle 22B), and is held by the Y carriage 43 and the Z carriage 44 so as to be movable in the YZ axis directions integrally with the spindle 22A. The microscope 23 photographs the pattern and kerf on the surface of the workpiece W from the surface side of the workpiece W. This microscope 23 is used for aligning the workpiece W and the blades 21A, 21B, and for a kerf check to confirm the position of the kerf.

The table 31 has a workpiece holding surface 31a formed in a porous shape. The workpiece holding surface 31a adsorbs and holds the workpiece W from its back side. At this time, a dicing tape T that is transmissible to infrared light Li (near-infrared light, see FIG. 4) is attached to the back side of the workpiece W, and the workpiece holding surface 31a adsorbs and holds the workpiece W via the dicing tape T. The table 31 is held by an X-carriage 36 (described later) so as to be movable in the X-axis direction, and is held by a rotation unit 37 (described later) so as to be rotatable about a rotation axis CA.

In addition, an infrared light source 50 is provided inside the table 31, which will be described in detail later, and which irradiates infrared light Li upward in the Z direction toward the back side of the workpiece W (see FIG. 4). For this reason, the table 31 is made of a material that can transmit the infrared light Li, such as infrared-transmitting glass.

The processing section 16 is provided with an X base 32, an X guide 34, an X drive section 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 its upper surface in the Z-axis direction. 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 section 35 uses an actuator such as a linear motor, and moves (drives) the X carriage 36 in the X-axis direction along the X guide 34.

The rotation unit 37 is provided on the upper surface of the X-carriage 36. The table 31 is provided on the upper surface of the rotation unit 37. The rotation unit 37 is rotated by a rotation drive section 38 (see FIG. 9) that is composed of a motor, gears, etc. As a result, the rotation unit 37 rotates the table 31 in the θ direction around its rotation axis CA.

The workpiece W transported from the load port 12 by the transport mechanism 14 is adsorbed and held by the table 31, and moves and rotates integrally with the table 31.

The processing unit 16 is also 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 gate-like shape that straddles the X base 32 in the Y-axis direction. The Y guide 42 is provided on the side of the Y base 41 in the X-axis direction. The Y guide 42 has a shape that extends in the Y-axis direction, and guides each of the pair of Y carriages 43 along the Y-axis direction. 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.

A Z carriage 44 is provided on each of the pair of Y carriages 43 so as to be movable in the Z-axis direction via a Z drive unit 48 (see FIG. 9) that is configured with an actuator such as a stepping motor. A spindle 22A and a microscope 23 are provided on one side of the Z carriage 44, and a spindle 22B is provided on the other side of the Z carriage 44.

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 moved in the X, Y, and Z-axis directions and the θ direction relative to the table 31 and the workpiece W. This allows the position of the microscope 23 to be adjusted relative to the workpiece W before alignment begins, and the blades 21A, 21B to be aligned relative to the processing start position of the workpiece W after alignment detection. In addition, when dicing the workpiece W with the blades 21A, 21B, 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 can be performed.

Since the dicing device 10 is a so-called twin spindle dicer, the processing control unit 78 selectively performs, for example, the meeting cutting method and the step cut method as the dicing process for the workpiece W. Note that in this embodiment, the case where dicing is performed using the step cut method will be described as an example.

Figure 3 is an explanatory diagram for explaining the step cut method. As shown in Figure 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 forming a circuit are laminated on the surface of a substrate such as silicon. In this step cut method, blades 21A and 21B (or blades 21A and 21B of the same shape) with different thicknesses are attached to spindles 22A and 22B. In the step cut method, the blades 21A and 21B first form a first kerf 25A (see Figure 17) along the street C with the blade 21A rotating at high speed for each street C, and then form a second kerf 25B (see Figure 17) at the bottom of the first kerf 25A along the street C with the blade 21B rotating at high speed.

The machining depth of the first kerf 25A and the second kerf 25B formed by the step cut method is particularly deep for the second kerf 25B, so it is difficult to perform a kerf check (hereinafter simply referred to as kerf check) to confirm the positions of the first kerf 25A and the second kerf 25B using only the microscope 23 as described above in FIG. 17. For this reason, in this embodiment, the kerf check is performed using the infrared light source 50 and the microscope 23.

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

The number of infrared light sources 50 is not particularly limited, and for example, multiple infrared light sources 50 may be two-dimensionally arranged in the table 31 so that infrared light Li is irradiated to all measurement points (or the entire area of the workpiece W) where the kerf check is performed in the workpiece W. In addition, a so-called edge-type illumination method may be used in which the infrared light source 50 is provided at the end of the table 31 and the infrared light Li emitted from the infrared light source 50 is guided to a position directly below each measurement point via a light guide plate and then refracted upward in the Z direction.

The infrared light Li emitted from the infrared light source 50 is incident on the back side of the workpiece W through the dicing tape T and passes through the workpiece W in the Z direction. As a result, transmitted light LT of the infrared light Li is emitted from the front side of the workpiece W toward the upper side in the Z direction. At this time, a portion of the infrared light Li incident on the back side of the workpiece W passes through the formation region CR of the first kerf 25A and the second kerf 25B within the workpiece W. The formation region CR also includes the pattern P (which may include a structure) on the surface of the workpiece W formed around the first kerf 25A and the second kerf 25B.

When the infrared light Li passes through the formation region CR in this manner, a portion of the infrared light Li passes through the dicing tape T, then passes through the space in the second kerf 25B, and is emitted as transmitted light LT from the surface side of the workpiece W. Another portion of the infrared light Li passes through the dicing tape T and the silicon region in the workpiece W in sequence, then passes through the space in the first kerf 25A, and is emitted as transmitted light LT from the surface side of the workpiece W. The remainder of the infrared light Li passes through the dicing tape TP, then passes through the silicon region in the workpiece W without passing through the spaces in the first kerf 25A and the second kerf 25B, and is emitted as transmitted light LT from the surface side of the workpiece W.

Here, the longer the distance that the infrared light Li passes through the silicon region in the workpiece W, the greater the amount of infrared light Li absorbed by the silicon region, and the less the amount of transmitted light LT. Conversely, the shorter the distance that the infrared light Li passes through the silicon region in the workpiece W, the less the amount of infrared light Li absorbed by the silicon region, and the more the amount of transmitted light LT increases. For this reason, of the transmitted light LT that passes through the formation region CR, the transmitted light LT that passes through the space in the second kerf 25B, i.e., the transmitted light LT that indicates edge information of the bottom of the second kerf 25B, has the greatest amount of light. Next, the transmitted light LT that passes through the first kerf 25A has the greatest amount of light, and the transmitted light LT that does not pass through the first kerf 25A and the second kerf 25B has the smallest amount of light.

[microscope]
Fig. 5 is a side view of the microscope 23 of the first embodiment, showing 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 front surface side of the workpiece W and photographs the workpiece W from the front surface side when detecting the alignment of the workpiece W and the blades 21A, 21B (during alignment) and when performing the above-mentioned kerf check.

The microscope 23 is equipped with a coaxial illumination unit 52 and a color camera 56.

The coaxial illumination unit 52 corresponds to the first illumination unit of the present invention, and irradiates the formation area CR on the surface of the workpiece W with coaxial illumination light L1 (corresponding to the first illumination light of the present invention) during alignment detection and 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 in a position facing the surface of the workpiece W and the workpiece holding surface 31a, the half mirror 52b is disposed above the objective lens 52c in the Z direction, and the coaxial illumination light source 52a is disposed to the side of the half mirror 52b.

The coaxial illumination light source 52a is, 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 this coaxial illumination light L1. Note that the coaxial illumination light L1 is not particularly limited as long as it is light having a different wavelength range from the infrared light Li, and visible light and infrared light may be used.

The half mirror 52b reflects the coaxial illumination light L1 incident from the coaxial illumination light source 52a toward the objective lens 52c. The half mirror 52b also transmits the specularly reflected light L1A and transmitted light LT (described below) incident from the objective lens 52c and emits them toward the color camera 56.

The objective lens 52c has an optical axis O1 parallel to the Z direction, and irradiates the coaxial illumination light L1 incident from the half mirror 52b along the optical axis O1 onto the formation area CR on the surface of the workpiece W. As a result, the specularly reflected light L1A of the coaxial illumination light L1 specularly reflected at the formation area CR passes through the objective lens 52c and the half mirror 52b in order and enters the color camera 56.

In addition, transmitted light LT that has passed through the forming area CR during kerf checking is incident on the objective lens 52c. The transmitted light LT that has entered the objective lens 52c passes through the half mirror 52b and enters the color camera 56. Therefore, a mixed light LM of the specularly reflected light L1A and the transmitted light LT is incident on the color camera 56 during kerf checking. If necessary, it is also possible to selectively irradiate the front side of the workpiece W with coaxial illumination light L1 by the coaxial illumination unit 52 and irradiate the back side of the workpiece W with infrared light Li by the infrared light source 50.

When detecting alignment, the color camera 56 captures the mixed light LM that has passed through the half mirror 52b and is incident thereon. When checking the kerf, the color camera 56 separates the mixed light LM that has passed through the half mirror 52b and is incident thereon into specularly reflected light L1A and transmitted light LT, and then captures the specularly reflected light L1A and transmitted light LT separately and simultaneously. The following is a detailed explanation of how the color camera 56 captures the specularly reflected light L1A and transmitted light LT during the kerf check.

The color camera 56 includes an imaging lens 56a and a color image sensor 56b. The imaging lens 56a images the mixed light LM incident from the half mirror 52b on the light receiving surface of the color image sensor 56b.

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

6, the color filter array 58 is composed of multiple 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, and 58IR is arranged on each pixel 57 in an array pattern in which, for example, a portion of the color filter 58G is replaced with the color filter 58IR in a known Bayer array.

Color filters 58R, 58G, and 58B correspond to the first color filter of the present invention, and transmit only the specularly reflected light L1A, which is white light, from the mixed light LM. More specifically, color filter 58R transmits only the red light from the specularly reflected light L1A, color filter 58G transmits only the green light from the specularly reflected light L1A, and color filter 58B transmits only the blue light from the specularly reflected light L1A.

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 from the mixed light LM. As a result, the mixed light LM incident on the color filter array 58 is separated into specular reflected light L1A that transmits through each color filter 58R, 58G, 58B, and transmitted light LT that transmits through the color filter 58IR. As a result, the specular reflected light L1A is imaged by the multiple pixels 57 for each color filter 58R, 58G, 58B of the color imaging element 56b, and the transmitted light LT is imaged by the multiple pixels 57 for the color filter 58IR. In other words, the specular reflected light L1A and the transmitted light LT are simultaneously imaged by the color imaging element 56b while being separated from each other.

In this embodiment, since it is sufficient that the color image sensor 56b can simultaneously capture the specularly reflected light L1A and the transmitted light LT while separating them from each other, for example, an infrared cut filter (not shown) may be disposed instead of each of the color filters 58R, 58G, and 58B. In this case, the number of pixels in the bright field image D1 and the transmitted image D2 shown in Figures 7 and 8 described below can be made uniform by adjusting the arrangement of both the infrared cut filter and the color filter 58IR so that the number of pixels 57 capturing the specularly reflected light L1A is the same as the number of pixels 57 capturing the transmitted light LT.

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

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

As described above, among the transmitted light LT that has passed through the formation region CR, the amount of transmitted light LT that has passed through the space in the second kerf 25B is the greatest, followed by the transmitted light LT that has passed through the space in the first kerf 25A, and then the transmitted light LT that has not passed through the first kerf 25A or the second kerf 25B. 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) are bright enough to be recognized, but the image of the pattern P in the formation region CR is dark.

In this way, the color camera 56 captures the specularly reflected light L1A and the transmitted light LT separately, thereby simultaneously and coaxially capturing the bright field image D1 and the transmitted image D2.

[General Control Unit]
Fig. 9 is a functional block diagram of the general control unit 60 of the dicing apparatus 10 of the first embodiment. As shown in Fig. 9, the general control unit 60 generalizes and controls each unit of the dicing apparatus 10 to execute various operations including alignment detection, alignment, dicing, kerf check, and correction of the dicing.

In addition to the spindles 22A and 22B, microscope 23, X drive unit 35, rotation drive unit 38, Y drive unit 46, and Z drive unit 48, an operation unit 62, a memory unit 64, and a display unit 66 are connected to the general control unit 60.

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

The overall control unit 60 executes a control program (not shown) stored in the memory unit 64, and functions as a blade drive control unit 70, a movement control unit 72, an imaging control unit 74, a detection unit 76, a processing control unit 78, an image processing unit 80, and a measurement unit 82. Note that the "unit" of the overall control unit 60 may be a "circuit", a "device", or a "equipment". In other words, the "unit" may be composed of firmware, software, hardware, or a combination of these.

The blade drive control unit 70 controls the rotational drive of the blades 21A and 21B by the spindles 22A and 22B.

The movement control unit 72 drives the relative movement mechanism 49, which includes 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), to move the blades 21A, 21B, and the microscope 23 relative to the table 31 and the workpiece W.

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

In addition, when aligning the workpiece W with the blades 21A and 21B after alignment detection, the movement control unit 72 drives the relative movement mechanism 49 to align the blades 21A and 21B with the processing start position of the workpiece W.

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

Furthermore, when checking the kerf after dicing, the movement control unit 72 drives the relative movement mechanism 49 to adjust the position of the microscope 23 to a position facing the formation region CR.

The photography control unit 74 controls the coaxial illumination and photography of the workpiece W by the microscope 23, and the irradiation of infrared light Li onto the workpiece W by the infrared light source 50. During alignment detection, after adjusting the position of the microscope 23 as described above, the photography control unit 74 executes coaxial illumination by the coaxial illumination unit 52 and imaging of the specularly reflected light L1A by the color image sensor 56b. As a result, the color camera 56 captures a bright-field image D1, and outputs this bright-field image D1 to the detection unit 76.

During kerf checking, the imaging control unit 74 adjusts the position of the microscope 23 as described above, and then 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, while also causing the color imaging element 56b to capture the regular reflection 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 the bright field image D1 and the transmitted image D2 to the image processing unit 80.

The detection unit 76 detects the edge information of the alignment detection pattern of the workpiece W contained in the bright field image D1 input from the color camera 56 using a known image recognition method to perform alignment detection to detect the position of each street (not shown) of the workpiece W. The detection unit 76 then 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 (alignment) between the street C to be machined and the blades 21A and 21B.

After completing the alignment, 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 to perform dicing processing by the step cut method using the blades 21A, 21B for each street C of the workpiece W. After the dicing processing is performed, the movement control unit 72 adjusts the position of the microscope 23 and the photography control unit 74 photographs the bright field image D1 and the transmission image D2 with the color camera 56 to check the first kerf 25A and the second kerf 25B. The bright field image D1 and the transmission image D2 are then input from the color camera 56 to the image processing unit 80. When the processing control unit 78 receives the kerf check result from the measurement unit 82 described below, it corrects the position of the blades 21A, 21B when dicing the next street C.

Figure 10 is an explanatory diagram showing an example of a composite image DC generated by the image processing unit 80. As shown in Figure 10 and the already described Figure 9, the image processing unit 80 generates a composite image DC by combining the bright field image D1 and the transmission image D2 input from the color camera 56. As already described, 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) are bright enough to be recognized, but the image of the second kerf 25B (edge portion) is dark and cannot be recognized. Conversely, in the transmission image D2, the image of the second kerf 25B and the image of the first kerf 25A are bright enough to be recognized, but the image of the pattern P is dark.

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 this embodiment, the image of the first kerf 25A is also included in the peripheral portion, and the image processing unit 80 trims both the images of the first kerf 25A and the second kerf 25B from within the transmission image D2, but it is also possible to 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 crushed in the bright field image D1. Note that in this 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.

At this time, since the bright-field image D1 and the transmission image D2 are images captured coaxially by the color camera 56, the position range of the image of the second kerf 25B in the transmission image D2 coincides with the position range of the image of the second kerf 25B in the bright-field image D1. Therefore, the image processing unit 80 can easily determine the position range of the second kerf 25B that is crushed in black 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 can accurately superimpose the trimmed image of the second kerf 25B on the image area of the second kerf 25B that is crushed in black in the bright-field image D1. As a result, a composite image DC is obtained 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. Then, the image processing unit 80 outputs the composite image DC to the measurement unit 82.

The measuring unit 82 detects the positions of the first kerf 25A and the second kerf 25B relative to the pattern P on the surface of the workpiece W, for example, based on the composite image DC input from the image processing unit 80. Next, the measuring unit 82 performs a kerf check to detect the amount of positional deviation (Y-direction positional deviation) between the actual position value and the target value for each of the first kerf 25A and the second kerf 25B. The measuring unit 82 then outputs the kerf check result to the processing control unit 78. As a result, based on the kerf check result input from the measuring 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.

The measuring unit 82 may perform a kerf check by detecting the width of each of the first kerf 25A and the second kerf 25B, as well as the amount of positional deviation between the first kerf 25A and the second kerf 25B, and detecting the processing quality, such as the presence or absence of chipping.

[Operation of the First Embodiment]
Fig. 11 is a flow chart showing the flow of dicing processing and car checking of the workpiece W by the dicing device 10 of the first embodiment having the above-mentioned configuration. As shown in Fig. 11, when the workpiece W is attracted and held on the table 31, each part of the general control unit 60 operates. Then, the movement control unit 72 drives the relative movement mechanism 49 to adjust the position of the microscope 23 to a position where the alignment detection pattern on the surface of the workpiece W can be photographed (step S1).

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 specularly reflected 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.

Then, the detection unit 76 performs alignment detection to detect the position of each street C of the workpiece W using 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).

Next, the movement control unit 72 drives the relative movement mechanism 49 based on the alignment detection result by the detection unit 76 to align the street C to be machined with the blades 21A and 21B (step S3).

Once the alignment is complete, 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 to perform dicing processing using the step cut method with the blades 21A, 21B for each street C of the workpiece W (step S4).

Then, when the dicing process for one or more streets C is completed, the kerf check is started. First, the movement control unit 72 drives the relative movement mechanism 49 to adjust the position of the microscope 23 to a position where the formation region CR formed in the workpiece W by the dicing process can be photographed (step S5).

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 starts imaging by the color image sensor 56b. This simultaneously irradiates the formation area CR from the front side of the workpiece W with the coaxial illumination light L1 by the coaxial illumination unit 52, and irradiates the formation area CR from the back side of the workpiece W with the infrared light Li by the infrared light source 50 (step S6).

The mixed light LM, which is the specularly reflected light L1A of the coaxial illumination light L1 specularly reflected at the formation region CR and the transmitted light LT that has passed through the formation region CR, enters the color camera 56 via the objective lens 52c and the half mirror 52b, and then enters the color filter array 58 of the color image sensor 56b via the imaging lens 56a.

The mixed light LM incident on the color filter array 58 is separated into specularly reflected light L1A that passes through each color filter 58R, 58G, 58B, and transmitted light LT that passes through each color filter 58IR. The specularly reflected light L1A is then captured by a plurality of pixels 57 for each color filter 58R, 58G, 58B of the color image sensor 56b. At the same time, the transmitted light LT is captured by a plurality of pixels 57 for each color filter 58IR of the color image sensor 56b. As a result, the specularly reflected light L1A and the transmitted light LT are captured simultaneously and coaxially by the color image sensor 56b while being separated from each other (step S7). As a result, a bright field image D1 obtained by capturing the specularly reflected light L1A and a transmitted image D2 obtained by capturing the transmitted light LT are simultaneously output from the color camera 56 to the image processing unit 80.

In this embodiment, when the microscope 23 photographs the formation area CR from the front side of the workpiece W, the infrared light source 50 irradiates the formation area CR from the back side of the workpiece W with infrared light Li, thereby obtaining a bright field image D1 in which the pattern P and the first kerf 25A can be recognized, and a transmission image D2 in which at least the second kerf 25B can be recognized.

When the image processing unit 80 acquires the bright-field image D1 and the transmission image D2 from the color camera 56 (step S8), it detects and trims the image of the second kerf 25B from the transmission image D2, for example, as described in FIG. 10 above. Next, the image processing unit 80 superimposes the trimmed image of the second kerf 25B on the image area of the second kerf 25B that is blackened in the bright-field image D1, thereby generating a composite image DC and outputting 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 to the pattern P becomes clear. In addition, the positional relationship of the second kerf 25B to the first kerf 25A also becomes clear.

Furthermore, in this embodiment, the bright-field image D1 and the transmission image D2 are captured coaxially by the color camera 56, so that it is possible to omit positional deviation correction when synthesizing the image of the second kerf 25B in the transmission image D2 with the bright-field image D1. As a result, the synthetic image DC can be generated easily and in a short time.

Then, the measuring unit 82 performs a kerf check to detect the amount of positional deviation between the actual measured value and the target value of each of the first kerf 25A and the second kerf 25B relative to the pattern P based on the composite image DC input from the image processing unit 80, and outputs the kerf check result to the processing control unit 78 (step S10). At this time, the positional relationship of the edge of the second kerf 25B relative to the pattern P and the positional relationship of the second kerf 25B relative to the first kerf 25A can be clearly recognized based on the composite image DC, so that the kerf check can be performed with higher accuracy than before, especially for the second kerf 25B, which has a deep processing depth.

The machining control unit 78 controls the movement control unit 72 based on the kerf check result input from the measurement unit 82 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 accuracy along the next and subsequent streets C. In particular, in this embodiment, the kerf check can be performed with higher accuracy than in the past for the second kerf 25B, improving the machining accuracy of the second kerf 25B.

As described above, in the first embodiment, the coaxial illumination unit 52 irradiates the formation area CR with the coaxial illumination light L1, and the infrared light source 50 irradiates the formation area CR with the infrared light Li, and the color camera 56 separates the specular reflection light L1A and the transmitted light LT by wavelength and captures them, thereby obtaining 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. As a result, the first kerf 25A and the second kerf 25B can be recognized well based on the bright-field image D1 and the transmitted image D2 at a lower cost and in a shorter time than in the past, without using a microscope 23 with a large NA or a white light interferometer.

[Second embodiment]
Fig. 12 is a block diagram of a dicing apparatus 10 according to the second embodiment. Fig. 13 is a side view of a microscope 23 according to the second embodiment. In the first embodiment, the specular reflected light L1A and the transmitted light LT are wavelength-separated and imaged by the color image sensor 56b of the color camera 56, but in the second embodiment, the specular reflected light L1A and the transmitted light LT are wavelength-separated and imaged without using the color image sensor 56b.

As shown in Figures 12 and 13, the dicing device 10 of the second embodiment has basically the same configuration as the first embodiment, except that the microscope 23 is provided with a half mirror 52d, a transmission filter 52e, and a transmission filter 52f, and a first camera 59A and a second camera 59B are provided instead of the color camera 56. Therefore, the same reference numerals are used for components that are functionally or structurally the same as those of the first embodiment, and their description is omitted. In the second embodiment, the imaging unit of the present invention is composed of the half mirror 52d, the transmission filter 52e, the transmission filter 52f, the first camera 59A, and the second camera 59B.

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 portion of the mixed light LM (corresponding to the first light of the present invention) incident from the half mirror 52b to the upper side in the Z direction, and reflects the remainder of the mixed light LM (corresponding to the second light of the present invention) to the side, in this case, in the X direction. Note that various light separation elements other than the half mirror 52d may be used as long as they can split the mixed light LM into two.

The transmission filter 52e (corresponding to the first filter of the present invention) is disposed above the half mirror 52b in the Z direction and on the optical path of the mixed light LM, and is a bandpass filter that transmits only light in the wavelength range of the specularly reflected light L1A (coaxial illumination light L1). As a result, when the mixed light LM is incident on the transmission filter 52e from the half mirror 52d, only the specularly reflected light L1A is transmitted and emitted toward the first camera 59A described below.

The transmission filter 52f (corresponding to the second filter of the present invention) is disposed to the side of the half mirror 52b (the reflection direction side of the mixed light LM) and on the optical path of the mixed light LM, and is a bandpass filter that transmits only light in the wavelength range of the transmitted light LT (infrared light Li). As a result, when the mixed light LM is incident on the transmission filter 52f from the half mirror 52d, only the transmitted light LT is transmitted and emitted toward the second camera 59B described below.

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 include a color filter array 58.

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. As a result, the first image sensor 92a captures only the specularly reflected light L1A and outputs a bright field image D1 to the general control unit 60. At this time, unlike the color image sensor 56b of the first embodiment, the first image sensor 92a captures the specularly reflected light L1A using all pixels 57 within the light receiving surface (within the effective area), and therefore a bright field image D1 with a 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 that has sensitivity to the specularly reflected light L1A.

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 imaging element 92b that does not have a color filter array 58. The second imaging lens 90b forms an image of the transmitted light LT that has passed through the transmission filter 52f on the light receiving surface of the second imaging element 92b. As a result, the second imaging element 92b captures only the transmitted light LT and outputs the transmitted image D2 to the general control unit 60. At this time, the second imaging element 92b can also capture the transmitted light LT using all the pixels 57 in the light receiving surface, so that a transmitted image D2 with a higher resolution than that of the first embodiment can be obtained. The transmission filter 52f may also be provided on the light receiving surface of the second imaging element 92b. In this case, the second camera 59B becomes a camera that has sensitivity to the transmitted light LT.

In the second embodiment, the imaging control unit 74 executes coaxial illumination by the coaxial illumination unit 52 and imaging of the specularly reflected light L1A by the first imaging element 92a during alignment detection. This causes the first camera 59A to capture a bright field image D1, and outputs this 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 executed.

During the kerf check, the photography control unit 74 executes coaxial illumination by the coaxial illumination unit 52, irradiation of the workpiece W with infrared light Li by the infrared light source 50, imaging of the regular reflection light L1A by the first imaging element 92a, and imaging of the transmitted light LT by the second imaging element 92b. As a result, after the bright field image D1 is simultaneously captured by the first camera 59A and the transmitted image D2 is simultaneously captured by the second camera 59B, 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, the image processing unit 80 generates a composite image DC, the measurement unit 82 performs a kerf check, and the machining position is corrected by the machining control unit 78.

In this way, 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 reflected light L1A and the transmitted light LT can be easily wavelength-separated and simultaneously imaged, as in the first embodiment. As a result, the same effect as in the first embodiment can be obtained. In addition, by using the first camera 59A and the second camera 59B (monochrome cameras), a bright field image D1 and a transmitted image D2 with higher resolution than in the first embodiment can be obtained, so that the accuracy of the kerf check of the first kerf 25A and the second kerf 25B (particularly the second kerf 25B) can be further improved.

[Modification of the second embodiment]
Fig. 14 is a side view of a modified example of the microscope 23 of the second embodiment. In the second embodiment, the mixed light LM is wavelength-separated into the specularly reflected light L1A and the transmitted light LT using the half mirror 52d and the transmission filters 52e and 52f, but the above-mentioned wavelength separation may be performed using a dichroic mirror 52g (corresponding to the wavelength separation element of the present invention) as shown in Fig. 14. 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.

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 specularly reflected light L1A and the transmitted light LT.

As described above, in the modified example of the second embodiment, the dichroic mirror 52g is used to separate the mixed light LM into the specularly reflected light L1A and the transmitted light LT, which reduces the number of components of the microscope 23 compared to the second embodiment, thereby making the microscope 23 smaller and less expensive.

[Third embodiment]
15 is a side view of the microscope 23 of the dicing apparatus 10 of the third embodiment. The microscope 23 of each of the above embodiments performs coaxial illumination by irradiating the surface (such as the formation region CR) of the workpiece W with coaxial illumination light L1, but the microscope 23 of the third embodiment simultaneously performs coaxial illumination and oblique illumination (also referred to as tilt illumination) on the surface of the workpiece W.

The dicing device 10 of the third embodiment has a basically the same configuration as the dicing device 10 of the first embodiment, except that the coaxial illumination unit 52 (coaxial illumination light source 52a) emits light (e.g., red light) in a specific wavelength range λA within white light (visible light) as coaxial illumination light L1, and is equipped with a ring illumination unit 54.

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

The general control unit 60 of the third embodiment simultaneously executes the irradiation of the surface of the workpiece W with coaxial illumination light L1 by the coaxial illumination unit 52, the irradiation of the surface of the workpiece W with oblique illumination light L2 by the ring illumination unit 54, and the irradiation of the back side of the workpiece W with infrared light Li by the infrared light source 50. As a result, a mixed light LM of the specular reflected light L1A, scattered light L2A, and transmitted light LT is incident on the color camera 56 of the third embodiment. Note that, if necessary, it is also possible to selectively perform the irradiation of the surface of the workpiece W with coaxial illumination light L1 by the coaxial illumination unit 52 and the irradiation of the surface of the workpiece W with oblique illumination light L2 by the ring illumination unit 54.

The color camera 56 of the third embodiment separates the mixed light LM that is incident after passing through the half mirror 52b into specularly reflected light L1A, scattered light L2A, and transmitted light LT, and then simultaneously captures the specularly reflected light L1A, scattered light L2A, and transmitted light LT.

Specifically, in the third embodiment, the mixed light LM incident on the color filter array 58 is separated into specularly reflected light L1A that passes through each color filter 58R, scattered light L2A that passes through each color filter 58B, and transmitted light LT that passes through each color filter 58IR. As a result, the specularly reflected light L1A is imaged by the multiple pixels 57 for each color filter 58R of the color imaging element 56b, the scattered light L2A is imaged by the multiple pixels 57 for each color filter 58B, and the transmitted light LT is imaged by the multiple pixels 57 for each color filter 58IR.

In this way, in the third embodiment, the color imaging element 56b simultaneously captures the specularly reflected light L1A, the scattered light L2A, and the transmitted light LT while separating them from one another. As a result, as in the above embodiments, a bright field image D1 and a transmitted image D2 are obtained, and a dark field image (not shown, same below) of the surface of the workpiece W is obtained by capturing the scattered light L2A only with a plurality of pixels 57 for the color filter 58B. Therefore, the color camera 56 can capture the bright field image D1, the transmitted image D2, and the dark field image simultaneously and coaxially.

In the third embodiment, during the alignment detection described above, the imaging control unit 74 executes coaxial illumination by the coaxial illumination unit 52, oblique illumination by the ring illumination unit 54, and imaging of the regular reflection light L1A and the scattered light L2A by the color image sensor 56b. As a result, the color camera 56 captures a bright field image D1 and a dark field image, and outputs these bright field image D1 and dark field images to the detection unit 76.

In addition, during the kerf check described above, the photography control unit 74 of the third embodiment executes coaxial illumination by the coaxial illumination unit 52, oblique illumination by the ring illumination unit 54, irradiation of infrared light Li by the infrared light source 50 onto the workpiece W, and imaging of the regular reflection light L1A, scattered light L2A, and transmitted light LT by the color image sensor 56b. As a result, the color camera 56 simultaneously captures a bright field image D1, a transmission image D2, and a dark field image, and outputs these bright field image D1, transmission image D2, and dark field image to the image processing unit 80.

The detection unit 76 of the third embodiment performs the alignment detection described above based on the bright field image D1 and dark field image input from the color camera 56. Here, the surface of the workpiece W contains both a pattern that is easier to recognize in the bright field image D1 created by coaxial illumination, and a pattern that is easier to recognize in the dark field image created by oblique illumination. Therefore, in the third embodiment, a pattern that is difficult to recognize using only the bright field image D1 can be recognized 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 the above embodiments.

The image processing unit 80 of the third embodiment generates a composite image DC by synthesizing the bright-field image D1, the transmission image D2, and the dark-field image input from the color camera 56. Here, the dark-field image is obtained by capturing an image of at least a portion of the scattered light L2A scattered at the bottom of the first kerf 25A by the color image sensor 56b. Therefore, the image of the first kerf 25A (edge portion) in the formation region CR is easier to recognize in the dark-field image than in the bright-field image D1. Therefore, the image processing unit 80 trims the image of the first kerf 25A (including its peripheral portion) from within 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. This makes the positional relationship of the edge of the first kerf 25A to the pattern P clearer than in the above embodiments.

In addition, the image processing unit 80 of the third embodiment, like the above embodiments, trims the image of the second kerf 25B from within the transmission image D2 and superimposes this trimmed image of the second kerf 25B on the image area of the second kerf 25B within the bright-field image D1. This completes the generation of the composite image DC by the image processing unit 80. Even in this case, since the bright-field image D1, the transmission image D2, and the dark-field image are captured coaxially by the color camera 56, it is possible to omit positional deviation correction when combining these images, and as a result, the composite image DC can be generated easily and in a short time.

The measurement unit 82 of the third embodiment, like the above embodiments, performs a kerf check of the first kerf 25A and the second kerf 25B against the pattern P based on the composite image DC input from the image processing unit 80. At this time, the positional relationship of the edge of the first kerf 25A against the pattern P is also made clearer in the composite image DC of the third embodiment, so that the measurement unit 82 can perform a kerf check of the first kerf 25A with higher accuracy than the above embodiments.

In the second embodiment and its modified examples, oblique illumination and acquisition of dark field images may be performed during alignment detection and kerf checking. In this case, a configuration (a combination of a half mirror and a transmission filter, a dichroic mirror, etc.) for wavelength-separating the mixed light LM into specularly reflected light L1A, scattered light L2A, and transmitted light LT, and a third camera (not shown) for capturing the scattered light L2A are added to the second embodiment and its modified examples.

In addition, in the third embodiment, the ring illumination unit 54 provides oblique illumination of the workpiece W, but various types of oblique illumination units capable of providing oblique illumination may be used instead of the ring illumination unit 54.

Furthermore, in the above third embodiment, red light is used as the coaxial illumination light L1 and blue light (short wavelength) that is 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 as the oblique illumination light L2. In other words, 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.

In the above embodiments, the case where the bright field image D1 and the transmission image D2 are synthesized to generate the synthesized image DC 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 of the second kerf 25B relative to the first kerf 25A is clear based on the positional relationship between the image of the first kerf 25A in the bright field image D1 and the image of the second kerf 25B in the transmission image D2, it is not necessarily necessary to synthesize the bright field image D1 and the transmission image D2. In this case, the measurement unit 82 performs a kerf check based on the bright field image D1 and the transmission image D2.

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

The microscope 110 has basically the same configuration as the microscope 23 of the second embodiment (see FIG. 13) except that it has a filter switching mechanism 111 instead of the half mirror 52d, the transmission filter 52e, the transmission filter 52f, and the second camera 59B. For this reason, the same reference numerals are used for components that are functionally or structurally the same as those in the second embodiment, and their description will be omitted.

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

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

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

As described above, by driving the filter switching mechanism 111 to sequentially place 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 specular reflected light L1A and the transmitted light LT in a time-division manner. Even in this case, alignment detection and kerf checks can be performed in the same manner as in the above embodiments, based on the bright field image D1 and the transmitted image D2 captured by the first camera 59A.

When the color image sensor 56b of the microscope 23 of the first embodiment is a COMS type, the color image sensor 56b can be controlled to capture the regular reflected light L1A by the multiple pixels 57 corresponding to each of the color filters 58R, 58G, and 58B, and capture the transmitted light LT by the multiple pixels 57 corresponding to each of the color filters 58IR, in a time-division manner.

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 can be added to the filter switching mechanism 111.

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

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

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

In each of the above embodiments, a dicing tape T is attached to the back surface of the workpiece W, and the workpiece holding surface 31a adsorbs and holds the workpiece W via the dicing tape T, but the workpiece holding surface 31a may also directly adsorb and hold the back surface of the workpiece W.

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

10 Dicing apparatus 10A Housing 12 Load port 14 Transport mechanism 16 Processing section 18 Cleaning section 21A, 21B Blade 22A, 22B Spindle 23 Microscope 31 Table 31a Workpiece holding surface 32 X base 34 X guide 35 X drive section 36 X carriage 37 Rotation unit 38 Rotation drive section 41 Y base 42 Y guide 43 Y carriage 44 Z carriage 46 Y drive section 48 Z drive section 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 Overall control unit 62 Operation unit 64 Memory unit 66 Display unit 70 Blade drive control unit 72 Movement control unit 74 Photography 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 imaging element 92b Second imaging element 110 Microscope 111 Filter switching mechanism 112A, 112B Transmission filter 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 Transmitted light LM Mixed light O1 Optical axis W Workpiece λA Wavelength range λB Wavelength range

Claims (10)

A kerf photographing device for photographing a kerf formed along a street of a workpiece from a surface side of the workpiece,
a first illumination unit that irradiates a first illumination light onto a formation region of the kerf from a front surface side of the workpiece;
A second illumination unit that irradiates the formation area from the back side of the work with second illumination light having an infrared wavelength range different from the wavelength range of the first illumination light;
an imaging unit into which a mixed light of a reflected light of the first illumination light reflected at the formation area and a transmitted light of the second illumination light which passes through the formation area from the back side of the work and is emitted from the front side of the work is incident, and which separates the mixed light into the reflected light and the transmitted light and simultaneously images them;
A calf imaging device comprising: the imaging unit is a color imaging element including a plurality of pixels arranged two-dimensionally and a plurality of color filters disposed on the plurality of pixels,
2. The calf imaging device according to claim 1, wherein 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 imaging unit,
a light separation element that separates the mixed light into a first light and a second light;
a first filter that is disposed on an optical path of the first light separated by the light separation element and transmits only the reflected light;
a first image sensor configured to capture an image of the reflected light that has passed through the first filter;
a second filter that is disposed on an optical path of the second light separated by the light separation element and transmits only the transmitted light;
a second image sensor configured to capture an image of the transmitted light that has passed through the second filter;
The calf imaging device according to claim 1 . The imaging unit,
a wavelength separation element that separates the mixed light into the reflected light and the transmitted light;
a first image sensor configured to capture an image of the reflected light that has been wavelength-separated by the wavelength separation element;
a second image sensor configured to capture an image of the transmitted light that has been wavelength-separated by the wavelength separation element;
The calf imaging device according to claim 1 . A table is provided to hold the workpiece from a back side thereof,
The calf imaging device according to claim 1 , wherein the second illumination unit is provided on the table. The kerf imaging device according to any one of claims 1 to 5, wherein the first illumination unit irradiates the formation area with coaxial illumination light as the first illumination light. the first illumination unit irradiates the formation region with coaxial illumination light as the first illumination light, and irradiates the formation 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 specularly reflected light of the coaxial illumination light specularly reflected at the formation region and scattered light of the oblique illumination light scattered at the formation region,
The calf imaging device according to claim 1 , wherein the imaging section separates the specularly reflected light and the scattered light and simultaneously captures the images. The kerf imaging device according to any one of claims 1 to 7, wherein 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 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 image including an image of the second kerf. The calf imaging device according to claim 8, further comprising an image processing unit that generates a composite image by combining the image of the second calf in the second captured image with the first captured image. A dicing apparatus for forming a kerf along a street of a workpiece from a surface side of the workpiece,
A dicing machine comprising the kerf photographing device according to any one of claims 1 to 9.

Images