JP6826750B2 - Imaging device and processing control system - Google Patents

Description

The present invention relates to an imaging device and a processing control system mounted on a work processing device.

The dicing device that cuts and groovs a workpiece such as a wafer on which a semiconductor device or an electronic component is formed includes at least a blade (rotary blade) that is rotated at high speed by a spindle, a work table that holds the workpiece, and a work table. The work is provided with X, Y, Z, and θ moving axes that change the relative positions of the work table and the blade, and cutting and grooving are performed on the work by the operation of each moving axis.

In such a dicing device, Patent Document 1 provides a second image pickup device that images a blade separately from the first image pickup device used for work alignment, and the second image pickup device is used for the first image pickup device. It has been proposed to detect the relative positional relationship between the image pickup device and the blade and adjust the relative positional relationship between the blade and the work (particularly the positional relationship regarding the groove pitch direction in grooving) so as to be appropriate. There is. According to this, with respect to the relative position of the blade with respect to the work, the positional deviation between the position recognized on the apparatus and the actual position can be detected and corrected, and the work recognized by the first imaging apparatus can be corrected. The tip of the blade (cutting edge) can be accurately aligned with the position of the planned cutting line.

International Publication No. 2009/081746

According to the method of Patent Document 1, it is not necessary to perform the conventional blade misalignment correction of detecting the blade misalignment by actually cutting the dummy work and measuring the cutting position, so that the dummy There is an advantage that the consumption of the work can be eliminated and the processing cost can be reduced.

However, in order to detect the misalignment of the blade, it is necessary to move the second image pickup device to the opposite position of the first image pickup device and the opposite position of the blade. Therefore, the detection accuracy is lowered due to the movement.

Further, since a process completely independent of the work alignment and cutting process is required, there is a problem that the processing time is increased. In particular, the position of the blade changes due to changes in the environment during machining (water temperature, air temperature, machining position of the workpiece, wear of the blade), but it is costly to provide a device that can maintain the machining environment at all times. Invite an increase. Therefore, in order to realize high-precision machining that does not depend on the machining environment, it is desirable to increase the frequency of blade misalignment correction, but in the method of Patent Document 1, the frequency of misalignment correction is increased. There is a drawback that the processing time increases.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a dicing apparatus capable of performing highly accurate blade misalignment correction without causing a significant increase in machining time. ..

In order to achieve the above object, the dicing apparatus according to one aspect of the present invention includes a work table for holding a work, a processing means for processing the work, and a moving mechanism for relatively moving the work and the processing means. An imaging device that simultaneously images the work and the processing means and acquires a composite image obtained by combining the image of the processing means and the image of the work, and a control unit that controls the relative position of the processing means with respect to the work based on the composite image. And have.

According to this aspect, since the relative position of the processing means with respect to the work can be simultaneously detected from the composite image without moving the imaging device, the high-precision blade can be detected without significantly increasing the processing time. Positional deviation correction can be performed.

In the dying apparatus according to another aspect of the present invention, the processing means is a blade rotated by a spindle, and the moving mechanism is at least the Y direction parallel to the rotation axis of the blade with respect to the work and the X direction orthogonal to the rotation axis. The image pickup device has an optical axis along the Z direction orthogonal to the surface of the work, and is orthogonal to the objective lens for the work that forms an image of the surface of the work in the Y direction. A blade objective lens that has an optical axis along the direction and forms an image of the tip of the blade on the same surface as the image of the surface of the work and in the same direction in the Y direction, and for the work. The control unit is provided with an imaging means for capturing an image formed by the objective lens and the objective lens for the blade and acquiring a composite image obtained by combining the image of the surface of the work and the image of the tip of the blade. Based on the misalignment detecting means for detecting the misalignment of the tip of the blade in the Y direction with respect to the position in the Y direction of the planned cutting line on the surface of the workpiece in the image, and the misalignment detected by the misalignment detecting means. A mode in which the blade is moved relative to the work in the Y direction by a moving mechanism to provide a misalignment correction means for matching the position of the planned cutting line in the Y direction with the position of the tip of the blade in the Y direction. Can be.

According to this aspect, it is possible to correct the positional deviation between the position of the planned cutting line on the surface of the work and the tip of the blade with respect to the position of the blade in the Y direction relative to the work, and high-precision machining is possible. It becomes.

Further, the image of the surface of the work and the image of the tip of the blade used for correcting the misalignment move the image pickup device including the work objective lens, the blade objective lens, and the image pickup means with respect to the work and the blade. Since the composite image can be acquired at the same time without causing the image to be moved, the detection accuracy does not decrease due to the movement of the image pickup apparatus, and the position shift correction can be performed with high accuracy.

Further, since it is possible to detect the misalignment of the blade immediately before the start of cutting the scheduled cutting line of the workpiece or even during cutting, a special process for detecting the misalignment of the blade becomes unnecessary. .. Therefore, the machining time does not increase due to the detection of the misalignment. From this, it is possible to increase the frequency of performing blade misalignment correction, and without taking measures such as maintaining a constant processing environment to prevent the blade misalignment from occurring, which causes an increase in cost. High-precision machining that does not depend on the machining environment can be realized.

In the dicing apparatus according to still another aspect of the present invention, the blade objective lens has an optical axis in a direction different from the direction intersecting the rotation axis of the blade, and the image of the tip of the blade acquired by the imaging apparatus is obtained. It can be an embodiment having a blade wear detecting means for detecting the amount of wear of the blade based on the above.

According to this aspect, it is possible to detect the amount of wear of the blade together with the detection of the misalignment or independently by using the image pickup apparatus used for correcting the misalignment of the blade.

In the dicing apparatus according to still another aspect of the present invention, among the light passing through the work objective lens and the blade objective lens, a first polarizing plate for polarizing the light from the work passing through the work objective lens, and A second polarizing plate that polarizes the light from the blade that passes through the blade objective lens, and a second polarizing plate that polarizes the light from the workpiece that has passed through the first polarizing plate in a direction orthogonal to the polarization direction. , A third polarizing plate rotatably provided around the optical axis on the optical path through which the light from the work passing through the first polarizing plate and the light from the blade passing through the second polarizing plate pass. By rotating the third polarizing plate around the optical axis, the intensity ratio between the image of the surface of the work and the image of the tip of the blade in the composite image acquired by the imaging device can be adjusted. Can be done.

According to this aspect, in the composite image acquired by the image pickup apparatus, it is possible to adjust the intensity ratio between the image of the surface of the work and the image of the tip of the blade, and the intensity ratio is suitable according to the processing content and the like. can do.

According to the present invention, it is possible to perform highly accurate blade misalignment correction without causing a significant increase in processing time, and it is possible to realize highly accurate processing.

Overall configuration diagram illustrating the dicing apparatus to which the present invention is applied Perspective view showing the configuration of the machined part Configuration diagram of the optical system of the image pickup device The figure which illustrated the work image imaged by the image pickup apparatus The figure which exemplifies the blade image imaged by the image pickup apparatus The figure which illustrated the composite image which is taken by the image pickup apparatus Block diagram showing the configuration of the control unit The figure which illustrated the composite image which is taken by the image pickup apparatus

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram illustrating a dicing apparatus to which the present invention is applied.

The dicing device 1 includes a load port 51 on which a cassette containing a large number of work W mounted on the frame F is placed, a transport means 53 for transporting the work W, a processing unit 2 for processing the work W, and a processed portion 2. The work W is composed of a cleaning unit 52 that spin-cleans the work W, a control unit 7 that is arranged inside the dicing device 1 and controls the operation of each unit, and the like.

The unprocessed work W stored in the cassette placed on the load port 51 is conveyed to the processing section 2 by the conveying means 53, and the processing section 2 performs cutting, grooving, etc. for dividing into individual chips. Be given. Then, the processed work W processed by the processing unit 2 is conveyed to the cleaning unit 52 by the conveying means 53, cleaned by the cleaning unit 52, and then conveyed to the load port 51 by the conveying means 53 and stored in the cassette. Wash.

The processing unit 2 is configured as shown in FIG. 2, and the processing unit 2 includes spindles 22 and 22 with built-in high-frequency motors, which are arranged to face each other and have a blade 21 and a blade cover (not shown) attached to their tips. It has an image pickup device 23 that images the surface of the work W and the tip of the blade 21, and a work table 31 that sucks and holds the work W.

In the figure, only the image pickup device 23 provided in the vicinity of the spindle 22 of one (right side) of the two spindles 22 and 22 is shown, but the image pickup device 23 is in the vicinity of both spindles 22 and 22. It is provided in.

The processing section 2 is provided with an X table 33 which is guided by X guides 34 and 34 provided on the X base 36 and driven by a linear motor 35 in the X direction indicated by XX in the figure, and is provided on the X table 33. Is provided with a work table 31 via a rotary table 32 that rotates in the θ direction.

As a result, the work W conveyed from the load port 51 by the conveying means 53 is attracted and held by the work table 31 and moves together with the work table 31 to rotate in the θ direction during alignment and cut feed in the X direction during cutting. Etc. are performed.

Further, the processing portion 2 is provided with a gate-shaped Y base 44, and the side surface of the Y base 44 is guided by the Y guides 42 and 42. Y tables 41, 41 driven in the direction are provided. Each Y table 41 is provided with a Z table 43 that is driven in the Z direction indicated by ZZ in the figure by a driving means (not shown), and the Z table 43 has a built-in high frequency motor with a blade 21 attached to the tip. The spindle 22 and the image pickup device 23 are fixed. Further, a blade cover (not shown) is attached to the spindle 22, and the peripheral portion of the blade 21 is covered by the blade cover, and a supply nozzle for supplying cutting fluid and cooling water to the blade 21 is provided.

As a result, the blade 21 is rotated at high speed by the spindle 22 at, for example, 1,000 rpm to 80,000 rpm during cutting. Further, at the time of cutting, the blade 21 is index-fed in the Y direction and cut-fed in the Z direction with respect to the work W attracted and held by the work table 31.

The X, Y, and Z directions are orthogonal to each other, the rotation axis of the blade 21 is parallel to the Y direction, and the surface of the work W (the holding surface of the work W of the work table 31) is orthogonal to the Z direction. To do.

Further, the Y table 41, the Z table 43, the spindle 22, and the imaging device 23 are provided in two sets facing each other on the left and right sides, but since they have the same configuration and operation, only one (right side) is focused on below. I will explain.

The image pickup apparatus 23 is fixed to the Z table 43 together with the spindle 22 so that the position relative to the spindle 22 (blade 21) is fixed, and the spindle is driven by the Y table 41 and the Z table 43. It moves in the Y direction and the Z direction together with the 22 (blade 21).

Further, the image pickup apparatus 23 has a microscope and an image pickup element, and has a surface of the work W (hereinafter referred to as a work surface) and an annular tip portion (blade edge: hereinafter referred to as a blade tip portion) which is an outer peripheral edge of the blade 21. ) And are simultaneously imaged via the corresponding optical systems. Then, a composite image in which the image of the work surface and the image of the blade tip are superimposed (composited) is acquired. Further, if not at the same time, it is possible to capture an image of only the work surface and an image of only the blade tip.

As a result, the image pickup device 23 acquires an image used for alignment of the work W and correction of misalignment of the blade 21, which will be described later.

FIG. 3 is a configuration diagram showing the configuration of the optical system of the image pickup apparatus 23. As shown in the figure, the image pickup apparatus 23 has an optical path (referred to as "straight optical path 70") along the Z direction, which is the vertical direction, and the linear optical path 70 is a work having an optical axis along the Z direction. An objective lens 72, a low-magnification imaging lens 74, and a low-magnification CCD camera 76 are arranged.

When capturing an image of the work surface, the work objective lens 72 is arranged above the work W, and the light from the work surface passes through the work objective lens 72 and the low magnification imaging lens 74 and is a low magnification CCD. It is incident on the camera 76. As a result, the image of the work surface is magnified by the work objective lens 72 and imaged, and the imaged image is further magnified by the low magnification imaging lens 74 and imaged by the low magnification CCD camera 76. Then, the image of the work surface is acquired by the low-magnification CCD camera 76 as an electric signal (image signal) and as a work image. Here, the work image refers to an image obtained by imaging the surface of the work.

The low-magnification CCD camera 76 includes a CCD (Charge Coupled Device) image sensor, which is a solid-state image sensor as an image pickup means, but is not limited to a CCD image sensor, such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor. The image pickup means of the above may be used. The same applies to the high-magnification CCD camera 88 described later.

In the straight optical path 70, a first beam splitter 80 is arranged between the low magnification imaging lens 74 and the work objective lens 72, and a first branch optical path 82 branched from the linear optical path 70 by the first beam splitter 80 is provided. Be split. As a result, a part of the light traveling in the linear optical path 70 from the work objective lens 72 side toward the low magnification imaging lens 74 side is guided to the first branch optical path 82 by the first beam splitter 80.

A mirror 84, a high magnification imaging lens 86, and a high magnification CCD camera 88 are arranged in the first branch optical path 82, and the light guided to the first branch optical path 82 is reflected by the mirror 84 and is reflected by the high magnification imaging lens 86. After passing through, it is incident on the high-magnification CCD camera 88. As a result, the image of the work surface imaged by the work objective lens 72 is magnified by the high magnification imaging lens 86 and imaged by the high magnification CCD camera 88, and is acquired by the high magnification CCD camera 88 as an image signal and a work image. ..

Here, the magnification of the image is different between the low magnification imaging lens 74 and the high magnification imaging lens 86, and the high magnification imaging lens 86 has a larger magnification than the low magnification imaging lens 74. Therefore, when comparing the low-magnification CCD camera 76 and the high-magnification CCD camera 88, the high-magnification CCD camera 88 acquires an image with a narrower viewing range (angle of view), and the low-magnification CCD camera 76 acquires a wider viewing range (image). Get the image of the corner). The image acquired by the low-magnification CCD camera 76 and the high-magnification CCD camera 88 has an appropriate magnification in the control unit 7 described later according to the size of the pattern (street, alignment mark, etc.) existing on the work surface and the processing content. The image to be used is appropriately selected and used, but it is not specified which image is used. Further, it may be provided with only one of the low magnification CCD camera 76 and the high magnification CCD camera 88.

FIG. 4 is a diagram illustrating a work image captured by the low-magnification CCD camera 76 or the high-magnification CCD camera 88 as the work image acquired by the imaging device 23. As shown in the figure, the work image includes a magnified image of a chip T formed on the work and a street S formed between the chips T which are scheduled cutting lines to be cut by the blade 21. Further, in the work image of the figure, the horizontal direction corresponds to the X direction in the real space, and in the work image of the figure, the vertical direction corresponds to the Y direction in the real space, and the work image of the figure extends in the horizontal direction. The image area of the street S corresponds to a part of the planned cutting line parallel to the X direction in the real space.

In this specification, the position of the planned cutting line in the Y direction specifically indicates the position of the center line CS of the planned cutting line (street S) in the Y direction, and the center line is shown on the work image. It corresponds to the vertical position of CS.

The correspondence between the vertical and horizontal directions of the image and the direction of the real space can be set and changed arbitrarily.

Further, as shown in FIG. 3, a second beam splitter 90 is arranged between the first beam splitter 80 of the linear optical path 70 and the work objective lens 72, and is branched from the linear optical path 70 by the second beam splitter 90. A second branch optical path 92 is provided along the X direction.

As a result, a part of the light traveling in the linear optical path 70 from the low magnification imaging lens 74 side toward the work objective lens 72 side is guided to the second branch optical path 92 by the second beam splitter 90, and the second The light traveling through the bifurcated optical path 92 toward the second beam splitter 90 enters the straight optical path 70 by the second beam splitter 90 and travels toward the low magnification imaging lens 74 side.

A blade objective lens 94 having an optical axis along the X direction is arranged in the second branch optical path 92. The blade objective lens 94 is arranged at a position fixed with respect to the blade 21 and is arranged along a direction orthogonal to the rotation axis of the blade 21 (the central axis of the spindle 22).

Further, the peripheral portion of the blade 21 is covered with a blade cover (not shown), and the blade cover includes a blade objective lens 94 and a blade tip so that the blade tip can be imaged from the outside of the blade cover. An opening is provided to communicate as a space with the area to be imaged as a unit.

Further, the blade cover is provided with a shutter 96 that opens and closes the opening, and the shutter 96 is opened and closed by a motor controlled by the control unit 7. The shutter 96 is set to the open state when the image pickup device 23 images the tip of the blade, and the shutter 96 is set to the closed state when the image pickup is not performed to prevent cutting fluid and the like from splashing from the opening. To. A transparent plate may be installed in the opening instead of the shutter 96.

Therefore, when the opening of the blade cover is set to the open state by the shutter 96, the light from the tip of the blade passes through the opening of the blade cover and enters the objective lens 94 for the blade. Then, the light incident on the blade objective lens 94 passes through the blade objective lens 94 and is guided to the straight optical path 70 by the second beam splitter 90, and the image of the blade tip portion is magnified by the blade objective lens 94. The image is formed on the linear optical path 70 and on the same surface as the image of the work surface formed by the work objective lens 72.

The image of the blade tip imaged by the work objective lens 72 is passed through the low magnification imaging lens 74 of the straight optical path 70 and the high magnification imaging lens 86 of the first branch optical path 82, similarly to the image of the work surface. It is imaged by each of the low-magnification CCD camera 76 and the high-magnification CCD camera 88, and is acquired as an image signal and a blade image by each of the low-magnification CCD camera 76 and the high-magnification CCD camera 88. Here, the blade image refers to an image obtained by imaging the tip of the blade.

Further, in the region (imaging target region) to be imaged by the imaging device 23 as the blade tip portion, the position (height) in the Z direction is different from the position (height) of the rotation axis of the blade 21, and the blade 21 It is a position shifted in the Z direction with respect to the position (height) of the rotation axis of. That is, the optical axis of the blade objective lens 94 is oriented in a direction different from the direction intersecting the rotation axis of the blade 21, and the imaging direction of the blade 21 by the imaging device 23 (direction of the center of the imaging field) is the direction of the blade 21. The direction is shifted by a predetermined angle toward the outer peripheral side of the blade 21 with respect to the direction of the rotation axis. In the present embodiment, the range above the rotation axis of the blade 21 in the Z direction is set as the imaging target region.

As a result, in the imaging target region of the annular blade tip, the distance to the blade objective lens 94 increases as the position in the Z direction increases. The focusing distance is set so that the tip of the blade is reflected in the vicinity of the center on the blade image in the image target area with respect to the tip of the blade without wear, and the focus is set as an image of the tip 60 of the blade. An image is acquired in which the part where the image fits is the thinnest, and the farther away from that part, the thicker the image becomes due to defocusing. By acquiring such an image, it is possible to confirm the wear state of the blade tip portion as described later.

It should be noted that the function of checking the wear status of the blade tip as in the present embodiment may not be provided. In that case, the vicinity of the position of the blade tip where the rotation axis of the blade 21 and the position in the Z direction coincide with each other. The portion may be the imaging target region, or the other region of the blade tip portion may be the imaging target region.

FIG. 5 is a diagram illustrating a blade image captured by the low-magnification CCD camera 76 or the high-magnification CCD camera 88 as the blade image acquired by the imaging device 23. As shown in the figure, the blade image includes a magnified image of the blade tip 60 when a part of the annular blade tip is observed from a direction orthogonal to the rotation axis of the blade 21. Further, in the blade image of the figure, the horizontal direction corresponds to the Z direction in the real space, and in the blade image of the figure, the vertical direction corresponds to the Y direction in the real space, and the plane is orthogonal to the Y direction in the real space. The tip of the blade along the line appears as a strip-shaped image extending in the lateral direction in the blade image of the figure. Also, as shown in the figure, the central part that is in focus appears the thinnest, and the image becomes blurry and thicker toward the left and right edges.

In the present specification, the position of the blade tip (or blade 21) in the Y direction specifically indicates the position of the center of the blade tip in the thickness direction in the Y direction, and is laterally shown on the blade image. It is the position of the center line C60 of the extending band-shaped image, and corresponds to the position in the vertical direction of the center line C60.

Further, the images captured by the low-magnification CCD camera 76 and the high-magnification CCD camera 88 actually have a predetermined intensity ratio (brightness) between the work image as shown in FIG. 4 and the blade image as shown in FIG. Ratio) The superimposed (composited) composite image as shown in FIG. 6 is obtained.

In the composite image, the work image and the blade image are superimposed so that the Y direction of the work surface and the Y direction of the blade tip portion coincide with each other, and the X direction of the work surface and the Z direction of the blade tip portion coincide with each other. Then, when the position in the Y direction of the planned cutting line parallel to the X direction of the work surface and the position in the Y direction of the blade tip in the real space match, the composite image is also shown in the figure. The planned cutting lines (street S) and the vertical positions of the center lines CS and C60 of the blade tip 60 coincide with each other.

That is, the composite image is an image of the surface of the work, in which the image of the blade tip is superimposed on the position corresponding to the position of the blade tip in the Y direction in the real space, and the planned cutting line in the composite image ( The magnitude of the positional deviation between the vertical position of the center line CS of the street S) and the vertical position of the center line C60 of the blade tip 60 is the position of the planned cutting line and the blade tip in the Y direction in the real space. Indicates the magnitude of the deviation.

In addition to the composite image as described later, the image pickup apparatus 23 can selectively acquire an image of only the work image as shown in FIG. 4 and an image of only the blade image as shown in FIG.

Further, as shown in FIG. 3, a third beam splitter 100 is arranged between the first beam splitter 80 and the second beam splitter 90 of the linear optical path 70, and the third beam splitter 100 branches off from the linear optical path 70. A third branch optical path 102 is provided. As a result, the light traveling through the third branch optical path 102 toward the third beam splitter 100 side enters the straight optical path 70 and travels toward the work objective lens 72 side.

An optical system 104 for Koehler illumination and a white LED light source 106 are arranged in the third branch optical path 102.

Therefore, the white illumination light emitted from the LED light source 106 enters the linear optical path 70 via the Koehler illumination optical system 104 and the third beam splitter 100, and travels toward the work objective lens 72 side. Then, the illumination light is split by the second beam splitter 90 as illumination light traveling in each of the straight optical path 70 and the second branch optical path 92, and then the illumination light traveling in the straight optical path 70 passes through the work objective lens 72. The work surface is illuminated through the work surface to illuminate the work surface. Further, the illumination light traveling through the second branch optical path 92 is irradiated to the blade tip portion via the blade objective lens 94 to illuminate the blade tip portion.

Further, since these illumination lights pass through the Koehler illumination optical system 104 of the third branch optical path 102, they are irradiated to the work surface and the blade tip as uniform illumination light with little brightness unevenness.

Then, the illumination light radiated to the work surface and the blade tip portion is reflected and incident on the work objective lens 72 of the linear optical path 70 as light from the work surface, and also as light from the blade tip portion. By incident on the blade objective lens 94 of the second branch optical path 92, each image is acquired as a composite image as described above.

The LED light source 106 may be a light source other than the LED, and considering that water (cutting liquid or the like) is attached to the tip of the blade, the wavelength of the illumination light is less absorbed by water. The wavelength is desirable.

Further, between the second beam splitter 90 and the work objective lens 72 in the straight light path 70, between the second beam splitter 90 and the blade objective lens 94 in the second branch light path 92, and the first beam splitter in the straight light path 70. A first polarizing plate 110, a second polarizing plate 112, and a third polarizing plate 114 that allow only light polarized in the direction of the transmission axis to pass are arranged between the 80 and the third beam splitter 100.

The transmission axes of the first polarizing plate 110 and the second polarizing plate 112 pass through each of the first polarizing plate 110 and the second polarizing plate 112, merge at the second beam splitter 90, and enter the third polarizing plate 114. The light is arranged so that the light is polarized in the direction orthogonal to each other. For example, when the transmission axis of the first polarizing plate 110 is arranged in the X direction parallel to the paper surface of FIG. 3, the transmission axis of the second polarizing plate 112 is oriented in the Y direction orthogonal to the paper surface of FIG. Is placed in.

The third polarizing plate 114 is rotatably provided around the optical axis, and the direction of the transmission axis can be changed. The rotation of the third polarizing plate 114 is performed by driving a motor controlled by the control unit 7.

According to these first polarizing plates 110 to third polarizing plates 114, the illumination light emitted from the LED light source 106 is polarized in the first polarizing plate 110 and the second polarizing plate 112 according to the direction of the respective transmission axes. The work surface and the tip of the blade are irradiated as illumination light polarized in the direction. Then, of the light incident on the work objective lens 72 from the work surface and reaching the first polarizing plate 110, the light polarized in the direction of the transmission axis of the first polarizing plate 110, that is, mainly the work surface is irradiated. The reflected light of the polarized illumination light passes through the first polarizing plate 110 and proceeds to the third polarizing plate 114 of the straight light path 70. Further, of the light incident on the blade objective lens 94 from the blade tip and reaching the second polarizing plate 112, the light polarized in the direction of the transmission axis of the second polarizing plate 112, that is, mainly irradiating the blade tip. The reflected light of the polarized illumination light is transmitted through the second polarizing plate 112 and travels to the third polarizing plate 114 of the linear light path 70.

The light from the surface of these workpieces traveling to the third polarizing plate 114 and the light from the tip of the blade are polarized with the direction orthogonal to each other as the polarization direction, and form the direction of the transmission axis of the third polarizing plate 114. It transmits through the third polarizing plate 114 with a transmittance corresponding to the angle.

Therefore, by rotating the third polarizing plate 114 to adjust the direction of the transmission axis, the transmittances of the light from the work surface and the light from the blade tip portion transmitted through the third polarizing plate 114 can be changed. Can be done. Thereby, in the composite image obtained by each of the low magnification CCD camera 76 and the high magnification CCD camera 88, the intensity ratio between the work image and the blade image can be adjusted.

For example, as in the above example, it is assumed that the transmission axis of the first polarizing plate 110 is arranged in the X direction and the transmission axis of the second polarizing plate 112 is arranged in the Y direction. At this time, if the directions of the transmission axes of the third polarizing plate 114 are aligned with the X direction, the images acquired by the low-magnification CCD camera 76 and the high-magnification CCD camera 88 are only the work images on which the blade images are not superimposed. Then, when the direction of the transmission axis of the third polarizing plate 114 is rotated from the X direction to the Y direction and gradually changed, the images acquired by the low magnification CCD camera 76 and the high magnification CCD camera 88 are work images. The image becomes a composite image in which the blade image is superimposed on the image, and the strength of the blade image gradually increases with respect to the work image. When the directions of the transmission axes of the third polarizing plate 114 are aligned with the Y direction, the images acquired by the low-magnification CCD camera 76 and the high-magnification CCD camera 88 are only blade images on which the work image is not superimposed.

The control unit 7 changes the rotation position of the third polarizing plate 114 according to the processing content or the like performed based on the image acquired by the image pickup device 23, so that the work image and the blade image have an appropriate intensity ratio. An image, an image of only a work image, or an image of only a blade image is acquired.

As shown in FIG. 3, a filter 116 is arranged between the second polarizing plate 112 of the second branch optical path 92 and the blade objective lens 94. The filter 116 is arranged to select the wavelength of the blade image with respect to the work image in the composite image. That is, the LED light source 106 emits white illumination light (light having a wide wavelength band) suitable for observing the surface of the work, whereas the LED light source 106 is transparent to water for observing the blade 21. Light of a certain wavelength (eg, light of a wavelength of about 400 to about 600 nm) is desirable. Further, light having a small wavelength scattered by silicon dust (for example, light having a wavelength around 600 nm) is more desirable. Therefore, the filter 116 is arranged. As the filter 116, for example, LPF (long wave pass filter), SPF (short wave pass filter) and the like are desirable.

In the image pickup apparatus 23 shown in FIG. 3, the optical path for forming an image of the work surface is a straight optical path 70, but the optical path for forming an image of the tip of the blade may be a straight optical path, and the optical system is configured. It can be changed as appropriate.

Next, various processes of the control unit 7 using the above-mentioned imaging device 23 will be described.

FIG. 7 is a block diagram showing the configuration of the control unit 7. As shown in the figure, the control unit 7 includes a driving means 200, an alignment means 202, a cutting control means 204, a misalignment detecting means 206, a misalignment correcting means 208, a blade wear detecting means 210, and the like.

The drive means 200 appropriately controls the motor of the moving mechanism that moves the work table 31 in the θ direction and the X direction and the motor of the moving mechanism that moves the spindle 22 in the Y direction and the Z direction in the processing portion 2 of FIG. The work W or the blade 21 is moved in the desired direction or position, and the work W and the blade 21 are relatively moved. Further, the moving mechanism is provided with position detecting means for detecting the position of each moving portion, and the position in the X direction and the θ direction of the work W and the Y direction of the blade 21 based on the position information from each position detecting means. And the position in the Z direction, etc. are detected.

Further, the driving means 200 controls a motor for rotating the third polarizing plate 114 in the imaging device 23, and changes the intensity ratio of the work image and the blade image in the composite image acquired by the imaging device 23. In addition, the operation of each operating unit in the dicing device 1 is controlled.

The alignment means 202 controls the rotation position of the third polarizing plate 114 of the image pickup apparatus 23 through the driving means 200 at the time of aligning the work W before the start of machining immediately after the unprocessed work W is attracted and held on the work table 31. Then, the third polarizing plate 114 is set at a rotation position where only the work image can be obtained by the low magnification CCD camera 76 and the high magnification CCD camera 88.

As a result, an image of only the work image as shown in FIG. 4 is acquired from the low-magnification CCD camera 76 or the high-magnification CCD camera 88, and a pre-registered pattern (street or alignment mark) on the work surface is acquired based on the acquired work image. Etc.) is detected. It is also possible to acquire a composite image from the low-magnification CCD camera 76 or the high-magnification CCD camera 88 instead of the image of only the work image and perform this processing based on the composite image.

Then, the work W is rotated in the θ direction through the drive means 200, the scheduled cutting line is arranged parallel to the X direction, and the work W is arranged at a predetermined position in the X direction. As a result, the work W is aligned.

When a plurality of rectangular chips arranged in a matrix of the work W are divided into individual chips, the planned cutting lines are a plurality of scheduled cuttings at predetermined intervals along each of the two directions orthogonal to each other. There is a line. Then, after all the cutting of the scheduled cutting line in one direction is completed, the work W is rotated by 90 ° in the θ direction to cut the scheduled cutting line in the other direction, but the alignment of the work W based on the work image is performed. Of those two-direction cutting schedule lines of W, the cutting schedule line may be performed only before the cutting start of the cutting schedule line in the first cutting direction, or both before the cutting start of the cutting schedule line in both directions. It may be what you do.

The cutting control means 204 moves the blade 21 in the Y direction through the drive means 200 after the alignment of the work W is completed and before the start of cutting of the cutting scheduled line (first scheduled cutting line) to be cut first in the work W. The position of the tip of the blade in the Y direction (Y coordinate value) is made to match the position of the first scheduled cutting line in the Y direction (Y coordinate value).

Then, the blade 21 is moved in the Z direction, the blade 21 is cut and fed to a position having a predetermined cutting amount with respect to the work W, and then the work W is moved in the X direction. As a result, the position of the first scheduled cutting line of the work W is cut by the blade 21.

After that, after separating the blade 21 from the work W in the Z direction, the blade 21 is index-fed in the Y direction, and the position of the blade tip in the Y direction coincides with the position in the Y direction of the cutting schedule line to be cut next. Let me. Then, the same control as when cutting the first scheduled cutting line is performed. By repeatedly performing such control on all scheduled cutting lines of the work W, the cutting of the work W is completed.

The misalignment detecting means 206 is, for example, of the first scheduled cutting line after the position (Y coordinate value) of the blade tip in the Y direction is matched with the position in the Y direction of the first scheduled cutting line by the cutting control means 204. Before the start of cutting, the rotation position of the third polarizing plate 114 of the imaging device 23 is controlled through the driving means 200, and the work image and the blade image have an appropriate intensity ratio by the low-magnification CCD camera 76 and the high-magnification CCD camera 88. The third polarizing plate 114 is set at a rotation position where an image can be obtained.

As a result, a composite image as shown in FIG. 6 is acquired from the image pickup apparatus 23. Then, based on the composite image, the displacement of the blade tip in the Y direction with respect to the planned cutting line of the work W is detected.

Here, when the position of the blade tip in the Y direction does not deviate from the planned cutting line, that is, when the position of the planned cutting line in the Y direction and the position of the blade tip in the Y direction match. As shown in FIG. 6, the vertical position of the center line CS of the planned cutting line (street S) and the vertical position of the center line CS of the blade tip 60 coincide with each other on the composite image.

On the other hand, when the misalignment occurs, as shown in FIG. 8, the vertical position of the center line CS of the planned cutting line (street S) and the vertical position of the center line CS of the blade tip 60 on the composite image. There is a deviation from the position in the direction.

Therefore, the misalignment detecting means 206 has the vertical position of the center line CS of the planned cutting line (street S) and the vertical position of the center line CS of the blade tip 60 on the composite image acquired from the imaging device 23. By detecting whether or not the items match with, it is determined whether or not the position shift has occurred. Further, when the misalignment occurs, the magnitude of the misalignment between the vertical position of the center line CS and the vertical position of the center line CS of the blade tip 60 on the composite image is detected. It is also possible to detect the magnitude (displacement amount) of the position deviation of the blade tip portion in the Y direction with respect to the planned cutting line of the work W in space.

When the misalignment detecting means 206 detects the misalignment of the blade tip, the misalignment correcting means 208 moves the blade 21 in the positive or negative direction in the Y direction through the driving means 200, and moves the blade 21 in the Y direction of the blade tip. The position of is matched with the position of the first scheduled cutting line in the Y direction to correct the misalignment.

For example, as the first method of misalignment correction, when the direction in which the blade 21 is separated from the main body of the spindle 22 is the positive direction, the misalignment of the blade tip in the Y direction with respect to the first scheduled cutting line is in the positive direction. If the above occurs, the blade 21 is moved in the negative direction, and if the misalignment occurs in the negative direction, the blade 21 is moved in the positive direction.

Then, while the blade 21 is being moved in the Y direction in this way, the misalignment detecting means 206 continuously acquires a composite image from the image pickup apparatus 23, and the work image and the blade image acquired at each time point are combined. Detects misalignment based on. The misalignment correcting means 208 stops the movement of the blade 21 when the misalignment detecting means 206 no longer detects the misalignment. As a result, the position of the blade 21 in the Y direction can be matched with the position of the first scheduled cutting line in the Y direction.

Further, as a second method of misalignment correction, the misalignment detecting means 206 also detects the size (displacement amount) when the misalignment of the blade tip portion with respect to the first scheduled cutting line is detected in the Y direction. It shall be. The misalignment correcting means 208 acquires the misalignment amount from the misalignment detecting means 206, and moves the blade 21 through the driving means 200 in the direction in which the misalignment is reduced by the amount of the misalignment. As a result, the position of the blade 21 in the Y direction can be matched with the position of the first scheduled cutting line in the Y direction.

The misalignment correction process as described above may be performed only once before the start of cutting of each work W, may be performed before the start of cutting of each scheduled cutting line, or a plurality of scheduled cuttings may be performed. It may be done for each line. Further, it is possible to detect the misalignment by the misalignment detecting means 206 even during cutting of each scheduled cutting line, and when the misalignment is detected by this, the cutting by the cutting control means 204 is interrupted and the position is positioned. The cutting may be restarted after the deviation correction is performed, or when the index feed of the blade tip to the next scheduled cutting line is performed after the cutting of the scheduled cutting line when the misalignment is detected is completed. , The misalignment correction may be performed as a feed amount that reflects the detected misalignment amount.

Further, when the misalignment detecting means 206 detects the misalignment, the misalignment correcting means 208 determines the position (recognition position) of the blade 21 in the Y direction recognized by the driving means 200 based on the amount of the misalignment. May be corrected.

For example, the driving means 200 recognizes the position of the blade tip in the Y direction based on, for example, the position of the Y table 41 in the Y direction actually measured by the position detecting means, and the recognized position is defined as YB (coordinate value YB). To do. Then, the amount of displacement when the tip of the blade is displaced in the positive direction in the Y direction is set as a positive value, and the amount of displacement when the position is displaced in the negative direction is defined as a negative value. It is assumed that the amount of deviation detected as described above is DY.

At this time, the misalignment correction means 208 corrects the recognition position of the blade tip portion recognized by the drive means 200 by the position detection means from YB to YB + DY. As a result, if the position of the blade 21 does not change due to an environmental change or the like after the recognition position is corrected, the Y-direction recognition position of the blade tip recognized by the driving means 200 and the Y-direction position actually set. It is possible to eliminate the misalignment with and, and the tip of the blade can be accurately aligned with the position of the planned cutting line.

Here, in the first method of misalignment correction, it is not always necessary to detect the misalignment amount DY based on the composite image before the misalignment correction, and when the misalignment amount DY based on the composite image is not detected, The recognition position can be corrected by detecting the movement amount DM of the blade 21 in the Y direction required for the position deviation correction and setting the deviation amount DY = −DM.

Further, in the second method of position shift correction, the recognition position is corrected by correcting the recognition position instead of directly moving the blade 21 by the shift amount DY detected based on the composite image, so that the recognition position is the same as before the correction. The blade 21 may be moved to the surface, and as a result, the blade 21 may be moved by the amount of deviation.

The blade wear detecting means 210 controls the rotation position of the third polarizing plate 114 of the image pickup apparatus 23 through the driving means 200, and is located at the rotation position where only the blade image can be obtained by the low magnification CCD camera 76 and the high magnification CCD camera 88. 3 The polarizing plate 114 is set. As a result, only the blade image as shown in FIG. 5 is acquired from the low magnification CCD camera 76 or the high magnification CCD camera 88.

Here, as described above, in the blade image, the focused portion of the image of the blade tip portion is the thinnest.

On the other hand, the focused portion of the imaging target region of the blade tip portion changes depending on the diameter of the blade 21, and when the blade tip portion is worn, the position of the thinnest portion on the blade image also changes. That is, the thinnest portion on the blade image as shown in FIG. 5 moves to the right side (corresponding to the lower side in the Z direction in the real space) with the wear of the blade tip portion.

Therefore, the blade wear detecting means 210 detects the position where the blade tip portion appears the finest in the blade image acquired from the imaging device 23, and the amount of wear (wear amount) of the blade tip portion (blade edge) based on the detected position. ) Is detected. Specifically, the lateral position of the position where the tip of the blade is most thinly reflected on the blade image of FIG. 5 is detected. Then, the amount of wear on the tip of the blade is detected by detecting how much the detected lateral position has moved on the image with respect to the position when no wear has occurred.

As a result, when the amount of wear exceeds a predetermined threshold value, a warning display or the like prompting the replacement of the blade 21 is displayed on a monitor or the like (not shown).

It is also possible to obtain a composite image from the low-magnification CCD camera 76 or the high-magnification CCD camera 88 instead of only the blade image, and the composite image is acquired at the time of misalignment correction or the like. At that time, it is also possible to perform it in combination with other processing such as misalignment correction processing.

In the above embodiment, the case where the present invention is applied to a dicing apparatus using a blade 21 rotated by a spindle 22 as a processing means has been described. However, as a processing means, a laser irradiation means for irradiating a work W with laser light or the like has been described. The present invention can be similarly applied to a dicing apparatus using other means. In that case, if it is not possible to directly image the processing position in the processing means corresponding to the position of the blade tip, even if a specific part such as a mark provided corresponding to the processing position is imaged. Good.

S ... Street, T ... Chip, W ... Work, 1 ... Dying device, 2 ... Machining unit, 7 ... Control unit, 21 ... Blade, 22 ... Spindle, 23 ... Imaging device, 31 ... Work table, 32 ... Rotating table, 33 ... X table, 34 ... X guide, 35 ... linear motor, 36 ... X base, 41 ... Y table, 42 ... Y guide, 43 ... Z table, 44 ... Y base, 51 ... load port, 52 ... cleaning unit, 53 ... Conveying means, 60 ... Blade tip, 70 ... Straight optical path, 72 ... Work objective lens, 74 ... Low magnification imaging lens, 76 ... Low magnification CCD camera, 80 ... First beam splitter, 84 ... Mirror, 86 ... High magnification imaging lens, 88 ... High magnification CCD camera, 90 ... Second beam splitter, 94 ... Blade objective lens, 96 ... Shutter, 100 ... Third beam splitter, 104 ... Koehler illumination optical system, 106 ... LED light source, 110 ... 1st polarizing plate, 112 ... 2nd polarizing plate, 114 ... 3rd polarizing plate, 116 ... filter, 200 ... processing means, 202 ... alignment means, 204 ... cutting control means, 206 ... misalignment detecting means, 208 ... Misalignment correction means, 210 ... Blade wear detection means

Claims (6)

An imaging device mounted on a work processing device that processes a work with a rotatable blade.
The first objective lens facing the work and
A second objective lens facing the blade and having an optical axis in a direction different from the direction intersecting the rotation axis of the blade.
A photosynthetic optical system that synthesizes light from the work that passes through the first objective lens and light from the blade that passes through the second objective lens.
An imaging means for capturing light that has passed through the photosynthetic optical system,
An imaging device comprising. A first polarizing plate having a first transmission axis provided between the first objective lens and the photosynthetic optical system,
A second polarizing plate provided between the second objective lens and the photosynthetic optical system and having a second transmission axis different from the first transmission axis,
A rotatable third polarizing plate provided between the imaging means and the photosynthetic optical system,
The imaging device according to claim 1. A wavelength selection filter is provided between the second objective lens and the photosynthetic optical system.
The imaging device according to claim 1 or 2. The imaging device according to any one of claims 1 to 3,
A control device that controls the relative position of the blade and the work based on the image acquired by the image pickup device, and
A machining control system equipped with. The control device is
A misalignment detecting means for detecting a relative misalignment between the blade and the work based on an image acquired by the imaging device, and
Based on the detection result of the misalignment detecting means, the misalignment correcting means for correcting the misalignment, and
The machining control system according to claim 4. The control device includes blade wear detecting means for detecting the amount of wear of the blade based on an image acquired by the imaging device.
The machining control system according to claim 4 or 5.

Images