JP2018140469A - Method for testing workpiece, apparatus for testing and processing workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more suitably and easily detect grinding marks of a workpiece.SOLUTION: A testing method of this invention comprises: a processing step of processing a workpiece with a grindstone or an abrasive pad; a projection step of projecting, on a screen, a projection image, where an irregularity state formed on a processing target plane in processing step by irradiating the processing target plane of the workpiece with light from a light source, and by making the light reflected on the processing plane reach the screen; an imaging step of forming an imaging image by imaging the projection image on the screen; and a judgment step of judging the quality of the workpiece by grasping the irregularity state of the workpiece on the basis of the imaging image.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an inspection method for inspecting grinding marks formed on a workpiece, an inspection apparatus for a workpiece, and a processing apparatus.

  There are known processes for grinding various flat plate-like workpieces made of materials such as silicon, SiC, and sapphire with a grinding wheel, and polishing with a polishing pad. The grinding wheel is formed by solidifying abrasive grains such as diamond with a binder such as resin or metal. Moreover, this polishing pad comprised with a nonwoven fabric or a urethane pad is used with an abrasive grain, and grind | polishes the to-be-polished surface of a to-be-processed object.

  In a grinding process using a grinding wheel or a polishing process using a polishing pad, the process proceeds when the grinding wheel or the polishing pad touches the workpiece. In such processing, abrasive grains that fall off from the grinding wheel, grinding scraps or agglomerated abrasive grains that have been scraped off from the workpiece may enter between the grinding wheel or polishing pad and the workpiece. As machining progresses, deep and long grinding marks (scratches) are formed on the workpiece.

  When the workpiece on which the grinding marks are formed is divided to form individual device chips, the bending strength of the device chip is lowered. Therefore, there are a method for detecting a grinding mark by imaging a workpiece during or after processing, and a method for detecting a grinding mark based on the intensity of a reflected laser beam by irradiating the workpiece with a laser beam. Proposed.

JP 2016-49581 A JP 2010-17792 A

  However, in any of the methods, the configuration of the apparatus that realizes the detection of grinding marks is complicated, and the problem is that the apparatus is expensive.

  The present invention has been made in view of such problems, and its object is to more appropriately and easily detect irregularities such as grinding marks (scratches) formed on the work surface of the work piece. A workpiece inspection method, a workpiece inspection device, and a processing device are provided.

  According to the first aspect of the present invention, a processing step of processing a workpiece with a grinding wheel or a polishing pad, and a light from a light source is irradiated on the processing surface of the workpiece and reflected by the processing surface. A projection step in which the projected light reflecting the state of the irregularities formed on the processing surface in the processing step is reflected on the screen by the light reaching the screen, and the projection image of the screen is captured. A workpiece comprising: an imaging step for forming a captured image; and a determination step for determining the quality of the workpiece by grasping the uneven state of the workpiece based on the captured image An inspection method is provided.

  According to the second aspect of the present invention, the processing step of processing the workpiece with a grinding wheel or a polishing pad, and the surface of the workpiece irradiated with light from the light source is reflected by the processing surface. An imaging step for imaging the reflected light to form a captured image in which an image of the unevenness formed on the processing surface is reflected in the processing step; and the workpiece based on the captured image A determination step of determining the quality of the workpiece by grasping the state of the unevenness of the workpiece.

  According to the third aspect of the present invention, the captured image includes a central region of the processed surface including the center of the processed surface, and the captured image surrounds the central region. An inspection method for a workpiece according to the first aspect or the second aspect of the present invention is provided, wherein the outer peripheral area of the workpiece surface is not copied.

  According to the fourth aspect of the present invention, the holding table that holds the workpiece in a state in which the workpiece surface of the workpiece processed by the grinding wheel or the polishing pad is exposed, and the holding table held by the holding table. A light source that irradiates light on the surface to be processed of the workpiece and the light reflected by the surface to be processed irradiates the irregularities formed by the processing on the surface to be processed of the workpiece. Provided is a workpiece inspection apparatus comprising: a screen on which a projected image reflecting a state is projected; and an imaging unit that captures the projected image projected on the screen to form a captured image. Is done.

  According to the fifth aspect of the present invention, the holding table that holds the workpiece in a state where the processing surface of the workpiece processed by the grinding wheel or the polishing pad is exposed, and the holding table held by the holding table An inspection of a workpiece, comprising: a light source that irradiates light on a workpiece surface of the workpiece; and an imaging unit that detects the light reflected by the workpiece surface and forms a captured image. An apparatus is provided.

  In the fourth and fifth aspects of the present invention, the workpiece inspection apparatus includes a determination unit that determines the quality of the workpiece by grasping the state of the unevenness of the workpiece based on the captured image. Further, it may be provided. The determination unit may determine that the workpiece is defective when the concavity and convexity are detected continuously in a central region including the center of the processing surface and an outer peripheral region surrounding the central region. .

  In the fourth and fifth aspects of the present invention, the captured image includes a central region of the processing surface including the center of the processing surface, and the captured image surrounds the central region. The outer peripheral area of the surface to be processed may not be copied.

  A chuck table for holding a workpiece, a processing unit for processing the workpiece held on the chuck table with the grinding wheel or the polishing pad, and a processing surface of the processed workpiece. A cleaning unit, and an inspection unit for inspecting the unevenness state of a processing mark formed on the processed surface of the cleaned workpiece, the inspection unit inspecting the workpiece according to the present invention. A processing apparatus that is an apparatus is also one embodiment of the present invention.

  According to an inspection method, an inspection apparatus, and a processing apparatus according to an aspect of the present invention, a state of unevenness such as a grinding mark (scratch) formed on a processing surface of a workpiece by a light source, a screen, or a concave mirror Can be grasped based on a captured image captured using a simple configuration including. For capturing the captured image, light that is irradiated from the light source onto the processing surface of the workpiece and reflected from the processing surface is used.

  When unevenness is formed on the processing surface of the workpiece by processing, an image in which the unevenness is emphasized appears in the captured image formed by using the light irradiated and reflected on the processing surface. . Therefore, the state of the unevenness formed on the processing surface can be easily grasped, and the workpiece can be easily inspected. When it is confirmed that unevenness exceeding the allowable level is formed on the work surface of the work piece, the work piece is determined to be defective, the processing is stopped, and the state of the grinding wheel or polishing pad is changed. Can be confirmed.

  Therefore, according to one aspect of the present invention, a workpiece inspection method capable of more appropriately and easily detecting the state of irregularities such as grinding marks (scratches) formed on a workpiece surface of the workpiece, An inspection device and a processing device are provided.

FIG. 1A is a perspective view schematically showing a workpiece, and FIG. 1B is a perspective view schematically showing the workpiece to which a protective tape is attached. It is a perspective view which shows typically the processing apparatus containing an inspection apparatus. FIG. 3A is a side view schematically showing the grinding process, and FIG. 3B is a side view schematically showing the polishing process. It is a figure which shows the structural example of an inspection apparatus typically. FIG. 5A and FIG. 5B are diagrams schematically illustrating a configuration example of the inspection apparatus. It is a figure which shows the structural example of an inspection apparatus typically.

  Embodiments according to one aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1A is a perspective view schematically showing a workpiece inspection method, a workpiece inspection apparatus, or a workpiece in a machining apparatus according to an embodiment of the present invention.

  FIG. 1A schematically shows the workpiece 1. The workpiece 1 is, for example, a substantially disk-shaped substrate made of a material such as silicon, SiC (silicon carbide), or another semiconductor, or a material such as sapphire, glass, or quartz.

  The surface 1a of the workpiece 1 is divided into a plurality of regions by a plurality of division lines (streets) 3 arranged in a lattice pattern, and each region divided by the plurality of division lines 3 has an IC or the like. The device 5 is formed. Finally, the workpiece 1 is divided along the streets 3 to form individual device chips.

  Next, the protective tape stuck on the surface 1a of the workpiece 1 will be described with reference to FIG. FIG. 1B schematically shows the protective tape 7. The protective tape 7 has a function of protecting the device 5 and the like formed on the surface 1 a of the workpiece 1. The protective tape 7 protects the surface 1a side of the workpiece 1 from an impact applied during processing, conveyance, or the like on the back surface of the workpiece 1, and prevents the device 5 from being damaged.

  The protective tape 7 has a flexible film-like substrate and a glue layer (adhesive layer) formed on one surface of the substrate. For example, PO (polyolefin) is used for the base material. PET (polyethylene terephthalate), polyvinyl chloride, polystyrene, or the like having higher rigidity than PO may be used. For the glue layer (adhesive layer), for example, silicone rubber, acrylic material, epoxy material or the like is used.

  Next, a description will be given of a processing apparatus in which an inspection apparatus for inspecting the workpiece 1 on which irregularities are formed is incorporated. FIG. 2 is a perspective view schematically showing a grinding apparatus as a configuration example of a processing apparatus including an inspection apparatus.

  The grinding apparatus 2 includes a chuck table 8 installed on a disk-like turntable 6, a grinding unit 10 and a grinding unit 10 a on a substantially rectangular parallelepiped base 4. A column 12 and a column 12a are erected on the rear portion of the base 4, and a grinding unit 10 and a grinding unit 10a are provided on the column 12 and the column 12a, respectively.

  A disk-like turntable 6 is provided on the base 4 so as to be rotatable in a horizontal plane. Three chuck tables 8 are provided on the upper surface of the turn table 6 so as to be 120 degrees apart from each other in the circumferential direction. By rotating the turn table 6, each chuck table 8 has a workpiece loading / unloading area. The first grinding region and the second grinding region are positioned respectively. In the first grinding region, for example, rough grinding is performed, and in the second grinding region, for example, finish grinding is performed.

  The chuck table 8 has a suction path (not shown) having one end connected to a suction source (not shown) inside, and the other end of the suction path is connected to a holding surface 8 a on the chuck table 8. The holding surface 8a is composed of a porous member, and a negative pressure generated by the suction source is applied to the workpiece 1 placed on the holding surface 8a through the porous member, so that the chuck table 8 is covered. Hold the workpiece by suction.

  The grinding unit 10 includes a grinding wheel 18 held by a grinding wheel 16 that is rotationally driven by a spindle motor 14. The grinding unit 10a includes a grinding wheel 18a held by a grinding wheel 16a that is rotationally driven by a spindle motor 14a. The grinding wheels 18, 18 a held by the grinding wheels 16, 16 a are configured to be moved up and down by the processing feed units 20, 20 a, and contact the workpiece 1 held on the chuck table 8. The workpiece 1 is ground to a predetermined thickness.

  The portion on the front side of the base 4 is configured to be one step higher than the portion on which the turntable 8 is provided, and the cassette mounting tables 22 and 22 a are fixed to the front end of the base 4. A cassette 22 that accommodates the workpiece 1 before grinding is placed on the cassette placing table 22, and a cassette 24 a for placing the workpiece 1 that has been ground is placed on the cassette placing table 22 a. The

  A workpiece transfer robot 26 is installed on the base 4 adjacent to the cassette mounting tables 22 and 22a. The front portion of the base 4 further includes a positioning table 28 having a plurality of positioning pins, a workpiece loading mechanism (loading arm) 30, a workpiece unloading mechanism (unloading arm) 32, and a ground workpiece. And a spinner cleaning device 34 for cleaning and spin drying the workpiece.

  The grinding device 2 includes an inspection device 36 according to the present embodiment between the spinner cleaning device 34 and the cassette mounting table 22a. The inspection device 36 includes a holding table 38 that holds the workpiece 1 to be inspected, a light source 40, a screen 42, and an imaging unit 44.

  A light source 40 for emitting light to the entire workpiece 1 held by the holding table 38 is disposed obliquely above the holding table 38. As the light source 40, for example, an incandescent bulb or LED is used. However, there are no restrictions on the type and position of the light source 40. The light may be parallel light or non-parallel light. When the light is parallel light, for example, an optical element such as a concave mirror may be combined with the light source 40. Alternatively, parallel light or non-parallel light may be obtained using a light source that has a small light emitting area and can be regarded as a point light source.

  A screen 42 on which a projection image is formed by irradiating the reflected light is provided on the light path (optical path) reflected by the workpiece 1. The screen 42 is typically a flat screen, and is formed to have the same size as the workpiece 1 or the size that can display the central area of the workpiece. Since the unevenness formed on the surface to be processed by processing easily passes through the central region of the workpiece, for example, if a screen capable of projecting a range of about 50 mm in diameter near the center of the workpiece is used, the state of the unevenness Easy to check.

  In the present embodiment, the light source 40 is disposed obliquely above the holding table 38, and the screen 42 is disposed on the light path reflected by the workpiece 1. When light traveling obliquely downward from the light source 40 is radiated to the workpiece 1, this light is reflected by the exposed surface (here, the back surface 11 b) of the workpiece 1 and is applied to the screen 42. As a result, a projected image reflecting the state of the exposed surface of the workpiece 1 (that is, the back surface 1b) is formed on the screen 42.

  At a position where the screen 42 can be seen, an image pickup unit (image pickup means) 44 for picking up a projected image formed on the screen 42 and forming a picked-up image is arranged. The imaging unit 44 is, for example, a digital camera in which an imaging element such as a CCD or CMOS is combined with an optical element such as a lens, and outputs a captured image (video) formed by capturing a projection image to the outside. As the imaging unit 44, either a digital still camera that forms a still image or a digital video camera that forms a moving image can be used.

  Here, the inclination angle of the screen 42 will be described with reference to FIG. FIG. 4 schematically shows the positional relationship among the light source 40, the workpiece 1, the screen 42, and the imaging unit 44. As shown in FIG. 4, the screen 42 is preferably tilted so that the light reflected on the back surface 1 b of the workpiece 1 is perpendicularly incident on the screen 42.

  That is, the angle formed by the light incident on the workpiece 1 and the back surface 1b and the angle formed by the reflected light and the back surface 1b, the inclination angle of the screen 42 from the surface perpendicular to the back surface 1b of the workpiece 1, The screen 42 is tilted so as to match. In this case, since a projection image with extremely small distortion can be projected onto the screen 42, the state of the unevenness formed on the back surface 1b of the workpiece 1 can be grasped more accurately. At this time, the depth of field of the imaging unit 44 is appropriately adjusted in order to make a captured image formed by being captured by the imaging unit 44 clear.

  The imaging unit 44 confirms the state of unevenness formed on the processing surface (back surface 1b) of the workpiece 1 by processing from the captured image output from the imaging unit 44, and is processed based on the unevenness state. A determination unit (not shown) for determining the quality of the object 1 is connected.

  Note that the inspection apparatus 36 may include a concave mirror instead of the screen 42. If a concave mirror is provided in place of the screen 42, the light reflected from the processing surface of the workpiece 1 can be condensed on the imaging unit 44 by the concave mirror. Therefore, the amount of light reaching the imaging unit 44 increases and the imaging unit 44 can form a clearer captured image.

  In addition, the processing apparatus according to the present embodiment may not be a grinding apparatus that grinds a workpiece with a grinding unit that includes a grinding wheel, and may be a polishing apparatus that polishes a workpiece with a polishing unit that includes a polishing pad.

  Next, a workpiece inspection method according to this embodiment, which is performed by the inspection device 36 provided in the grinding device 2, will be described. In the inspection method, first, a processing step of processing a workpiece with a grinding wheel or a polishing pad is performed.

  The processing steps will be described with reference to FIGS. 3 (A) and 3 (B). FIG. 3A is a side view schematically showing the grinding process, and FIG. 3B is a side view schematically showing the polishing process.

  First, as shown in FIG. 3A, a case where the back surface 1b side of the workpiece 1 is ground by the grinding unit 10 provided in the grinding device 2 will be described. The workpiece 1 is placed on the holding surface 8a of the chuck table 8 through the protective tape 7 with the front surface 1a facing downward. Then, the workpiece 1 is sucked and held on the chuck table 8, and the back surface 1b side of the workpiece 1 is exposed upward. The chuck table 8 is positioned below the grinding unit 10 by rotating the turntable 6 (see FIG. 2) of the grinding device 2.

  Next, the spindle motor 14 of the grinding unit 10 is operated to rotate the grinding wheel 16. Further, the chuck table 8 is rotated around an axis perpendicular to the holding surface 8a. Then, when the machining feed unit 20 is operated to lower the grinding wheel 16 toward the workpiece 1 and the grinding wheel 18 mounted on the rotating grinding wheel 16 touches the back surface 1b side of the workpiece 1, the workpiece is processed. The object 1 is ground. When the grinding wheel 18 is positioned at a predetermined height by the processing feed unit 20, the workpiece 1 is thinned to a predetermined thickness.

  In the processing step, as shown in FIG. 3B, the back surface 1b side of the workpiece 1 may be polished by the polishing unit 10b. The polishing unit 10b is provided in the grinding device 2, for example, instead of the grinding unit 10a of the grinding device 2 shown in FIG. The polishing unit 10b may be provided in a polishing apparatus that does not include a grinding unit.

  The polishing unit 10b has a polishing pad 18b attached to a polishing wheel 16b. By operating a spindle motor (not shown) having one end connected to the other end of the spindle connected to the polishing wheel 16b, the polishing wheel 16b is rotated.

  In the polishing process by the polishing unit 10b, the holding surface of the chuck table 8 through the protective tape 7 with the surface 1a side of the workpiece 1 facing the chuck table 8 in the same manner as the above-described grinding process. The workpiece 1 is placed on 8a. Then, the workpiece 1 is sucked and held by the chuck table 8, and the back surface 1b side of the workpiece 1 is exposed upward.

  Then, the polishing wheel 16b is rotated, the chuck table 8 is rotated around an axis perpendicular to the holding surface 8a, and the polishing wheel 16b is lowered toward the workpiece 1. When the polishing pad 18b attached to the polishing wheel 16b comes into contact with the back surface 1b side of the workpiece 1, polishing is performed.

  In the grinding process using the grinding wheel 18 and the polishing process using the polishing pad 18b, the abrasive grains that have fallen off from the grinding wheel 18 and the grinding scraps and agglomerated grains that have been scraped off from the workpiece 1 are removed from the grinding wheel 18 or polished. In some cases, the pad 18b and the workpiece 1 may enter, and if the processing proceeds as it is, deep and long grinding marks (scratches) are formed on the workpiece 1. If the workpiece 1 on which the grinding marks are formed is divided and individual device chips are formed, the bending strength of the device chip is reduced, or the device chip does not function as a device.

  Therefore, in the workpiece inspection method according to the present embodiment, a grinding mark (scratch) formed on the workpiece surface of the workpiece 1 by performing a projection step, an imaging step, and a determination step next. The quality of the workpiece is judged by grasping the unevenness state such as.

  In the projecting step, the processed surface of the workpiece 1 that has been processed is irradiated with light, and the reflected light is projected onto the screen. First, the workpiece 1 that has been processed is transferred from the chuck table 8 to the holding table 38 of the inspection device 36 (see FIG. 2). In the process, the processed surface of the workpiece 1 is cleaned by the spinner cleaning device 34. The workpiece 1 is placed on the holding table 38 via the protective tape 7 with the front surface 1a side of the workpiece 1 facing the holding table 38, and the processing surface (back surface 1b) is exposed upward.

  Next, as shown in FIG. 4, light 46 is emitted from the light source 40. The light source 40 is provided in a mode (position, orientation, etc.) capable of irradiating light 46 to the entire workpiece 1 held by the holding table 38. Therefore, the light 46 emitted from the light source 40 is reflected by the processing surface (back surface 1 b) of the workpiece 1.

  A screen 42 is disposed on the path of the light 46 reflected by the workpiece 1. Therefore, the light 46 reflected by the processing surface (back surface 1b) of the workpiece 1 is irradiated to the screen 42, and a projection image corresponding to the uneven state formed on the processing surface is formed by processing. . Here, when the angle formed between the light 46 reflected by the workpiece 1 and the back surface 1b coincides with the inclination angle of the screen 42 with respect to the plane perpendicular to the workpiece surface, the projection is performed. Image distortion is extremely small.

  Thereafter, an imaging step is performed. The projected image is captured by the imaging unit 44 to form a captured image. At this time, the depth of field of the imaging unit (camera) 44 is appropriately adjusted to make the captured image clear. Then, the captured image formed by the imaging unit 44 is sent to a determination unit (not shown).

  After the imaging step, a determination step for determining the quality of the workpiece by grasping the state of the unevenness of the workpiece based on the captured image formed by the imaging unit 44 is performed. In the present embodiment, the captured image formed by the imaging unit 44 of the inspection apparatus 36 includes a projection image projected on the screen 42 instead of the processing surface (back surface 1 b) of the workpiece 1.

  The projected image is an image formed by irradiating the screen 42 with the light 46 irradiated on the processing surface of the workpiece. Here, the surface to be processed is substantially a mirror surface, and the light 46 is specularly reflected on the surface to be processed. However, when the surface to be processed has minute irregularities, the light 46 is partially reflected by the irregularities. Is diffused or converged.

  Therefore, the projected image is an image in which brightness and darkness reflecting the state of minute unevenness formed on the processing surface appears. Note that the phenomenon in which light and darkness in which the state of the unevenness of the mirror surface is reflected in an image formed by projecting the specularly reflected light onto a screen or the like is called a magic mirror phenomenon. The captured image formed by capturing the projection image projected on the screen 42 is more in the state of the unevenness formed on the processing surface than the captured image formed by directly capturing the processing surface. It is more useful for grasping. This is because the uneven state is emphasized by the magic mirror phenomenon.

  Therefore, the unevenness state of the workpiece can be easily grasped based on the captured image in which the projected image is captured. For example, when unevenness is not formed on the processing surface, the processing surface shown in the captured image has uniform brightness as a whole. For example, when unevenness is formed on the processing surface, a light and dark pattern in which the state of the unevenness formed on the processing surface is emphasized appears in the projected image captured in the captured image. That is, the uneven state of the workpiece can be grasped from the captured image.

  By the way, the determination unit (not shown) connected to the imaging unit 44 has a sufficient bending strength of the workpiece 1 based on the unevenness of the workpiece surface grasped from the captured image. A condition for determining whether or not there is registered in advance. The determination unit determines that the workpiece 1 is a non-defective product when the bending strength of the workpiece 1 is sufficient. On the other hand, when the bending strength of the work piece 1 is insufficient due to the unevenness formed on the work surface of the work piece 1, the determination unit determines that the work piece 1 is a defective product. judge.

  For example, if the determination unit detects a continuous unevenness (processing trace) in a central region including the center of the processing surface of the workpiece 1 and an outer peripheral region surrounding the central region, The workpiece 1 is determined to be defective. Here, the central region is, for example, a circular region from the center of the processing surface to a position one third to one fourth of the radius of the workpiece, and the outer peripheral region is It is a region other than the central region of the work surface.

  Concavities and convexities (machining traces) continuous to the central region and the outer peripheral region are difficult to be formed by normal processing, so that when such irregularities are detected, it can be determined that some abnormality has occurred in the processing apparatus. The determination unit determines that the workpiece 1 in which the unevenness is detected is defective.

  When the workpiece 1 is determined to be defective by the determination unit, the workpiece 1 can be discarded without being sent to a subsequent process. Then, when it is determined that the unevenness formed on the surface to be processed is caused by the processing in the processing step, the processing conditions and the like in the processing step are inspected. Also, check if there are any abnormalities in the grinding wheel or polishing pad.

  When the above-described inspection method for a workpiece is performed, the state of unevenness such as a processing mark (scratch) formed on the processing surface of the workpiece 1 by processing is based on a captured image formed using a simple configuration. Can be easily grasped.

  In the above embodiment, the workpiece 1 is directly irradiated with light from the light source. However, the parallel mirror reflected by the concave mirror is irradiated on the workpiece 1 by irradiating the concave mirror with the light emitted from the light source. Irradiation is also possible. Such a case will be described with reference to FIG.

  FIG. 5A is a diagram schematically illustrating a configuration example of the inspection device 36a. The inspection apparatus 36a shown in FIG. 5A includes a light source 40a, a concave mirror 48a, a holding table 38a, a screen 42a, an imaging unit 44, and a PC 50.

  In the inspection device 36a, the light emitted from the light source 40a is applied to the concave mirror 48a. The concave mirror 48a reflects parallel light toward the workpiece 1 held by the holding table 38a. When the workpiece 1 is irradiated with the parallel light, the workpiece 1 reflects the parallel light toward the screen 42a, and a projection image reflecting the uneven state of the workpiece is formed on the screen 42a. . The imaging unit 44 forms the projection image and sends the captured image to the PC 50. The PC 50 functions as a determination unit, and determines the quality of the workpiece by grasping the unevenness state of the workpiece based on the captured image.

  Furthermore, in the said embodiment, the light reflected by the to-be-processed object 1 is irradiated to a screen, a projection image is formed, and this imaging image is imaged by an imaging unit, and the imaging image is formed. However, a concave mirror may be installed in place of the screen, and the light reflected by the workpiece 1 may be irradiated onto the concave mirror to collect the light toward the imaging unit. Such a case will be described with reference to FIG.

  FIG. 5B is a diagram schematically illustrating a configuration example of the inspection device 36b. The inspection apparatus 36b shown in FIG. 5B includes a light source 40b, a concave mirror 48b, a holding table 38b, a concave mirror 48c, an imaging unit 44, and a PC 50.

  In the inspection device 36b, the light emitted from the light source 40b is applied to the concave mirror 48b. The concave mirror 48b reflects parallel light toward the workpiece 1 held on the holding table 38b. When the parallel light is irradiated, the workpiece 1 reflects the parallel light toward the concave mirror 48c. The concave mirror 48c reflects and condenses the parallel light applied to the concave mirror 48c toward the imaging unit 44. The imaging unit 44 detects the light reflected by the concave mirror 48c.

  The imaging unit 44 sends a captured image obtained by imaging to the PC 50. The PC 50 functions as a determination unit, and determines the quality of the workpiece by grasping the unevenness state of the workpiece based on the captured image. Here, the captured image is not an image obtained by capturing a projection image formed by irradiating the screen with the light reflected by the workpiece 1, but the light is reflected by the concave mirror 48 c and condensed on the imaging unit 44. It is an image that directly captures the emitted light.

  Since the light reflected by the workpiece 1 is condensed on the image pickup unit 44, the amount of light reaching the picked-up image increases, and the obtained picked-up image becomes relatively clear. Then, the uneven | corrugated state of the to-be-processed surface of the to-be-processed object 1 can be evaluated more correctly, and fine determination can be implemented by PC50 which functions as a determination unit.

  Furthermore, light is incident perpendicularly to the back surface 1b of the workpiece 1, and the reflected light is captured by the imaging unit 44 disposed in front of the back surface 1b of the workpiece 1, so that there is no distortion. A captured image can be obtained. An inspection apparatus 36c that can obtain a captured image without such distortion will be described with reference to FIG. FIG. 6 is a diagram schematically illustrating a configuration example of the inspection device 36c.

  The inspection device 36c includes a light source 40c, a beam splitter 52, and an imaging unit 44. The light emitted from the light source 40 c is converted into parallel light by a lens 56 a between the light source 40 c and the beam splitter 52. When the parallel light is incident on the beam splitter 52 disposed in front of the workpiece 1 held by the holding table 38 c, a part of the parallel light is reflected toward the workpiece 1.

  Then, as shown in FIG. 6, light is incident on the back surface 1b of the workpiece 1 from the front. At this time, it is not necessary to irradiate the entire surface of the back surface 1b of the workpiece 1 and, for example, the light is irradiated to a range of 50 mm in diameter including the center of the back surface 1b. The workpiece 1 reflects the light incident on the back surface 1b in the front direction. The light reflected by the workpiece 1 enters the beam splitter 52, and a part of the light is transmitted.

  The light transmitted through the beam splitter 52 is condensed on the imaging unit 44 by a lens 56b disposed between the beam splitter 52 and the imaging unit 44. The light collected and incident on the imaging unit 44 is finally collected by the lens 56 c included in the imaging unit 44 and reaches the light receiving element 54. The imaging unit 44 forms a captured image by capturing the light that has reached the light receiving element 54.

  When the inspection device 36c is used, the distortion of the captured image formed by the imaging unit 44 becomes extremely small, so that the unevenness state of the back surface 1b of the workpiece 1 can be more accurately evaluated.

  The captured image includes a central area of the processed surface including the center of the processed surface, and the captured image includes an outer peripheral area of the processed surface surrounding the central area. It does not have to be. In the central region of the processing surface including the center of the processing surface, since a processing mark formed on the processing surface of the workpiece is easily passed by grinding or the like, the state of unevenness formed in the central region It may be possible to determine the quality of the workpiece by grasping the above. For example, the central region is a circular region having a diameter of 50 mm.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 1 Workpiece 1a Front surface 1b Back surface 3 Line to be divided 5 Device 7 Protective tape 2 Grinding device 4 Base 6 Turntable 8 Chuck table 8a Holding surface 10, 10a Grinding unit 10b Polishing unit 12, 12a Column 14, 14a Spindle motor 16 , 16a Grinding wheel 16b Polishing wheel 18, 18a Grinding wheel 18b Polishing pad 20, 20a Processing feed unit 22, 22a Cassette mounting table 24, 24a Cassette 26 Workpiece transport robot 28 Positioning table 30 Workpiece loading mechanism (loading arm)
32 Workpiece unloading mechanism (unloading arm)
34 Spinner cleaning device 36, 36a, 36b, 36c Inspection device 38, 38a, 38b, 38c Holding table 40, 40a, 40b, 40c Light source 42, 42a Screen 44 Imaging unit 46 Light 48a, 48b, 48c Concave mirror 50 PC
52 Beam splitter 54 Light receiving element 56a, 56b, 56c Lens

Claims (9)

A processing step of processing the workpiece with a grinding wheel or a polishing pad;
Irradiation of the light from the light source onto the work surface of the workpiece, and the light reflected by the work surface reaches the screen, so that the unevenness formed on the work surface in the processing step is A projecting step of projecting the reflected projected image on the screen;
An imaging step of capturing the projected image of the screen to form a captured image;
A determination step of determining the quality of the workpiece by grasping the state of the unevenness of the workpiece based on the captured image, and a method for inspecting the workpiece. A processing step of processing the workpiece with a grinding wheel or a polishing pad;
Irradiation of the light from the light source onto the work surface of the workpiece, and imaging the light reflected by the work surface reflects the state of irregularities formed on the work surface in the processing step. An imaging step for forming a captured image in which the captured image is shown;
A determination step of determining the quality of the workpiece by grasping the state of the unevenness of the workpiece based on the captured image, and a method for inspecting the workpiece. In the captured image, a central region of the processing surface including the center of the processing surface is copied,
3. The workpiece inspection method according to claim 1, wherein the captured image does not include an outer peripheral area of the processing surface surrounding the central area. A holding table for holding the work piece in a state in which a work surface of the work piece processed with a grinding wheel or a polishing pad is exposed;
A light source for irradiating light on a work surface of the work piece held by the holding table;
A screen on which a projection image reflecting the state of the irregularities formed by the processing is reflected on the processing surface of the workpiece by irradiating the light reflected by the processing surface;
An imaging unit that captures a projected image projected on the screen to form a captured image;
A workpiece inspection apparatus comprising: A holding table for holding the work piece in a state in which a work surface of the work piece processed with a grinding wheel or a polishing pad is exposed;
A light source for irradiating light on a work surface of the work piece held by the holding table;
An imaging unit that detects the light reflected by the processing surface and forms a captured image;
A workpiece inspection apparatus comprising:   6. The workpiece inspection apparatus according to claim 4, further comprising a determination unit that determines the quality of the workpiece by grasping the state of the unevenness of the workpiece based on the captured image. .   The determination unit detects the unevenness when the concavity and convexity are detected continuously in a central region of the processing surface including the center of the processing surface and an outer peripheral region of the processing surface surrounding the central region. The workpiece inspection apparatus according to claim 6, wherein the workpiece is determined to be defective. In the captured image, a central region of the processing surface including the center of the processing surface is copied,
7. The workpiece inspection apparatus according to claim 4, wherein an outer peripheral region of the processing surface surrounding the central region is not copied in the captured image. A chuck table for holding the workpiece;
A processing unit for processing the workpiece held on the chuck table with the grinding wheel or the polishing pad;
A cleaning unit for cleaning the processed surface of the processed workpiece;
An inspection unit for inspecting the unevenness state of the processing mark formed on the processing surface of the cleaned workpiece,
The processing apparatus according to claim 4, wherein the inspection unit is a workpiece inspection apparatus according to claim 4.