Method for diagnosing a holding table and method for processing objects to be processed

Abstract

This provides a method for accurately diagnosing the condition of a holding table. [Solution] A diagnostic method for diagnosing the condition of a holding table, comprising: a fluid supply step of supplying a liquid or a mixture of liquid and gas to the holding surface (26) of the holding table (13); a suction step of sucking up the liquid or mixture of fluid supplied to the holding surface after the fluid supply step; an imaging step of capturing an image of the holding surface after the suction step; and a detection step of processing the image to detect areas where liquid or mixture of fluid remains as abnormalities.

Description

Technical Field

[0001] The present invention relates to a method for diagnosing a holding table that holds a holding object and a method for processing a workpiece.

Background Art

[0002] In a processing apparatus that processes a workpiece, the workpiece, which is a holding object, is sucked and held on the holding surface of a holding table for processing. In this type of holding table, if foreign matter such as processing chips accumulates on the holding surface, there is a risk that the workpiece cannot be stably held.

[0003] In the processing apparatus disclosed in Patent Document 1, imaging is performed in a state where air and water are jetted onto the holding surface of the holding table, followed by image processing, and the clogging state of the holding table is detected based on the image of the holding surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A method of directly imaging the fluid jetted from the inside of the holding table onto the holding surface and determining the clogging on the holding surface as in Patent Document 1 has a problem that it cannot be detected unless the degree of clogging is large. Therefore, there has been a desire to detect abnormalities when sucking and holding a holding object on the holding table earlier and with higher accuracy.

[0006] An object of the present invention is to provide a method capable of accurately diagnosing the state of a holding table that holds a holding object and a method for processing a workpiece in a state where the state of the holding table is accurately diagnosed.

Means for Solving the Problems

[0007] One aspect of the present invention is a diagnostic method for diagnosing the condition of a holding table, comprising: a fluid supply step of supplying a liquid or a mixture of liquid and gas to the holding surface of a holding table having a holding surface for holding an object to be held; a suction step of sucking up the liquid or the mixture of fluid supplied to the holding surface after the fluid supply step; an imaging step of capturing an image of the holding surface after the suction step; and a detection step of processing the image to detect areas where the liquid or the mixture of fluid remains as abnormalities.

[0008] The imaging step may involve imaging only the outer peripheral region of the holding surface, excluding the central region.

[0009] One aspect of the present invention is a method for processing an object, comprising: a fluid supply step of supplying a liquid or a mixture of a liquid and a gas to the holding surface of a holding table having a holding surface; a suction step of sucking up the liquid or the mixture of fluids supplied to the holding surface after the fluid supply step; an imaging step of capturing an image of the holding surface after the suction step; a detection step of processing the image to detect areas where the liquid or the mixture of fluids remains as abnormalities; and a processing step of holding the object to be processed on the holding table free of abnormalities and processing the object to be processed by an arbitrary processing unit after the detection step.

[0010] In this processing step, for example, the workpiece to be processed is subjected to machining. [Effects of the Invention]

[0011] According to the present invention's method for diagnosing a holding table, by supplying a liquid or two fluids to the holding surface of the holding table, then aspirating the liquid or two fluids, and detecting abnormalities based on an image taken of the holding surface after aspiration, the condition of the holding table regarding the suction holding of the object to be held can be accurately diagnosed. Furthermore, according to the present invention's method for processing an object to be processed, the object to be processed can be processed while the condition of the holding table has been accurately diagnosed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of a processing apparatus equipped with a holding table. [Figure 2] This is a diagram showing the fluid supply step. [Figure 3] This is a diagram showing the fluid supply step. [Figure 4] This figure shows the suction step and the imaging step. [Figure 5] This figure shows the results of imaging a holding table in a state without abnormalities. [Figure 6] This figure shows the results of imaging the retention table in a state where an abnormality is occurring. [Figure 7] This is a flowchart showing an example of a diagnostic process. [Modes for carrying out the invention]

[0013] The diagnostic method for the holding table of this disclosure will be described below with reference to the attached drawings. The processing apparatus 10 shown in Figure 1 is a grinding apparatus equipped with a grinding mechanism (rough grinding mechanism 11, finish grinding mechanism 12) as a processing mechanism, and performs grinding on a workpiece 14 held by suction on a holding table 13. The workpiece 14 is the object to be held by suction on the holding table 13, and the diagnostic method described later diagnoses the condition of the holding table 13. The X-axis, Y-axis, and Z-axis directions shown in each figure are perpendicular to each other. The X-axis and Y-axis directions are horizontal. The Z-axis direction is vertical, with the +Z direction being upward and the -Z direction being downward.

[0014] The processing apparatus 10 of this embodiment is a device that performs rough grinding using a rough grinding mechanism 11 and finish grinding using a finish grinding mechanism 12, and is equipped with three holding tables 13, but the number of grinding mechanisms and holding tables is not limited, and for example, there may be only one grinding mechanism or one holding table each.

[0015] Furthermore, the holding table to be diagnosed using the diagnostic method of the present invention may be provided in processing equipment or processing devices other than grinding equipment. For example, it can be applied to the diagnosis of holding tables provided in polishing equipment, cutting equipment, laser processing equipment, etc. It can also be applied to the diagnosis of holding tables that hold objects during processing other than processing, and one example of such processing is the cleaning of objects to be held.

[0016] The processing apparatus 10 includes a control unit 15 which consists of a processor that performs various processes and a memory that stores programs. The processing apparatus 10 is configured to perform a series of operations on the workpiece 14, consisting of loading, rough grinding, finish grinding, cleaning, and unloading, all fully automatically under the control of the control unit 15.

[0017] A disc-shaped turntable 21 is provided on the base 20 of the processing apparatus 10. The turntable 21 is rotatably supported about an axis extending in the Z-axis direction and is rotated by a turntable rotation mechanism 22 equipped with a motor. Three holding tables 13 are supported on the turntable 21. The three holding tables 13 are arranged at equal intervals (120° intervals) in the circumferential direction of the turntable 21.

[0018] Referring to FIGS. 2 to 4, the configuration of each holding table 13 will be described. The holding table 13 includes a frame body 23 and a disc-shaped porous plate 25 attached in a recess 24 on the upper surface side of the frame body 23. The porous plate 25 is made of a porous material such as ceramics, and fine pores are formed throughout. With the porous plate 25 attached in the recess 24, the upper surface of the frame body 23 and the upper surface of the porous plate 25 are flush, constituting a holding surface 26 for placing and holding the workpiece 14. The holding surface 26 is composed of an annular upper surface 27 which is the upper surface of the frame body 23 and an inner upper surface 28 which is the upper surface of the porous plate 25. In a plan view as shown in FIGS. 5 and 6, the inner upper surface 28 is located inside the annular upper surface 27. Each holding table 13 can be rotated by a holding table rotation mechanism 29. Although the detailed structure of the holding table rotation mechanism 29 is not shown, the rotating shaft that supports the holding table 13 is rotatably supported with respect to a pedestal provided on the turntable 21 side via a ring-shaped bearing or the like. Then, by transmitting the rotation of the motor to the rotating shaft via a transmission mechanism such as a belt, the holding table 13 rotates.

[0019] A flow path 33 is provided for connecting each of the suction source 30, the air supply source 31, and the liquid supply source 32 to the porous plate 25. One end of the flow path 33 opens at the bottom of the recess 24 of the frame body 23. The flow path 33 has a portion that rotates together with the holding table 13 and a portion that is arranged outside the holding table 13 and does not rotate, which are connected via a rotary joint. The flow path 33 branches in the middle and has a portion connected to the suction source 30 via an on-off valve 34, a portion connected to the air supply source 31 via an on-off valve 35, and a portion connected to the liquid supply source 32 via an on-off valve 36.

[0020] The suction source 30 has a suction pump for sucking air. When the suction source 30 is operated to open the on-off valve 34, a suction force acts on the porous plate 25 in the recess 24. Due to the negative pressure generated on the inner upper surface 28 of the holding surface 26 by this suction force, the workpiece 14 is sucked and held on the holding surface 26.

[0021] The air supply source 31 has a compressor that compresses and delivers air. When the air supply source 31 is operated and the on-off valve 35 is opened, high-pressure air is supplied to the porous plate 25 in the recess 24 through the flow path 33, and air is ejected from the inner upper surface 28 of the holding surface 26. The liquid supply source 32 has a tank for storing liquid and a pump for delivering liquid from the tank. When the liquid supply source 32 is operated and the on-off valve 36 is opened, pressurized liquid is supplied to the porous plate 25 in the recess 24 through the flow path 33, and liquid is ejected from the inner upper surface 28 of the holding surface 26. When both the air supply source 31 and the liquid supply source 32 are operated and the on-off valves 35 and 36 are opened, a two-fluid mixture of air and liquid is ejected from the inner upper surface 28 of the holding surface 26. By ejecting air, liquid, or two-fluid material from the holding surface 26, it is possible to easily separate the workpiece 14 held by the holding surface 26 from the holding surface 26 after processing, and to remove foreign matter (dirt) such as processing debris that has entered the pores of the porous plate 25.

[0022] The three holding tables 13 are sequentially positioned at the loading / unloading position, the first processing position, and the second processing position by the rotation of the turntable 21 in 120° increments. At the loading / unloading position, the workpiece 14 before processing is loaded onto the holding table 13 and held by suction on the holding surface 26, and the processed workpiece 14 is unloaded from the holding table 13. At the first processing position, the workpiece 14 held on the holding table 13 is roughly ground by the rough grinding mechanism 50. At the second processing position, the workpiece 14 held on the holding table 13 is finish ground by the finish grinding mechanism 60. Referring to Figure 1, the overall configuration of the processing apparatus 10 and the series of processes performed by the processing apparatus 10 will be explained. The operation of each of the following parts in the processing apparatus 10 is performed by the control of the control unit 15.

[0023] A cassette 40 placed on a base 20 contains a workpiece 14 before processing. A transport robot 41 transports the workpiece 14 from the cassette 40 to a temporary placement table 42, and positions the workpiece 14 on the temporary placement table 42 by bringing multiple positioning pins 43 into contact with its outer circumference.

[0024] The first transport unit 44 is equipped with a transport pad at the tip of a transport arm that can rotate around an axis in the Z-axis direction and move up and down in the Z-axis direction, and is capable of suction and holding the upper surface of the workpiece 14. The first transport unit 44 suction and holds the upper surface of the workpiece 14 held on the temporary storage table 42 with the transport pad, and operates the transport arm to place and transfer the workpiece 14 onto the holding surface 26 of the holding table 13 at the loading / unloading position. The suction source 30 is operated to open the on / off valve 34, and the negative pressure acting on the holding surface 26 of the holding table 13 (the inner upper surface 28 of the porous plate 25) suction and holds the workpiece 14 to the holding surface 26.

[0025] The turntable 21 is rotated 120° to move the holding table 13, which holds the workpiece 14 before processing, to the first processing position. Above the first processing position, the rough grinding wheel 51 of the rough grinding mechanism 50 is positioned. The rough grinding wheel 51 is arranged in an annular shape on the lower surface of a grinding wheel 53, which is provided at the lower end of a spindle 52 extending in the Z-axis direction. The spindle 52 is rotated by a motor (not shown). The rough grinding mechanism 50 is supported by a lifting table 54 that is movable in the Z-axis direction, and a ball screw 55 extending in the Z-axis direction is screwed into the lifting table 54. By rotating the ball screw 55 with a motor 56, the lifting table 54 moves in the Z-axis direction, and the position of the rough grinding mechanism 50 changes in the Z-axis direction along with the lifting table 54.

[0026] During rough grinding, the spindle 52 is rotated, and the holding table 13 is rotated by the holding table rotation mechanism 29 (Figures 2 to 4), driving the motor 56 to lower the rough grinding mechanism 50. As a result, the rough grinding wheel 51 and the workpiece 14 rotate relative to each other, and the rough grinding wheel 51 is pressed against the upper surface of the workpiece 14, causing the workpiece 14 to be ground. Liquid (for example, pure water) is supplied from the liquid supply source 57 to the vicinity of the machining point where the rough grinding wheel 51 contacts the workpiece 14. The supplied liquid is used for cooling the vicinity of the machining point and for cleaning the machining chips generated by the machining process.

[0027] Once the workpiece 14 has been ground to the desired thickness by rough grinding, the motor 56 is driven to raise the rough grinding mechanism 50 and separate the rough grinding wheel 51 from the workpiece 14. Next, the turntable 21 is rotated 120° to move the holding table 13, which holds the workpiece 14 after rough grinding, to the second processing position. Above the second processing position, the finishing grinding wheel 61 of the finishing grinding mechanism 60 is positioned. The finishing grinding wheel 61 contains finer abrasive grains than those contained in the rough grinding wheel 51. The finishing grinding wheel 61 is arranged in an annular shape on the lower surface of a grinding wheel 63, which is provided at the lower end of a spindle 62 extending in the Z-axis direction. The spindle 62 is rotated by a motor (not shown). The finishing grinding mechanism 60 is supported by a lifting table 64 that is movable in the Z-axis direction, and a ball screw 65 extending in the Z-axis direction is screwed into the lifting table 64. The motor 66 rotates the ball screw 65, causing the lifting table 64 to move in the Z-axis direction, and the position of the finishing grinding mechanism 60 changes in the Z-axis direction along with the lifting table 64.

[0028] During finish grinding, the spindle 62 is rotated, and the holding table 13 is rotated by the holding table rotation mechanism 29 (Figures 2 to 4), driving the motor 66 to lower the finish grinding mechanism 60. As a result, the finish grinding wheel 61 and the workpiece 14 rotate relative to each other, and the finish grinding wheel 61 is pressed against the upper surface of the workpiece 14, grinding the workpiece 14. Liquid (for example, pure water) is supplied from the liquid supply source 67 to the vicinity of the machining point where the finish grinding wheel 61 contacts the workpiece 14. The supplied liquid is used for cooling the vicinity of the machining point and for cleaning the machining chips generated by the machining process.

[0029] Once the workpiece 14 has been ground to the desired thickness by finish grinding, the motor 66 is driven to raise the finish grinding mechanism 60 and separate the finish grinding wheel 61 from the workpiece 14. Next, the turntable 21 is rotated 120° to move the holding table 13, which holds the workpiece 14 after finish grinding, to the loading / unloading position.

[0030] The second transport unit 45 is equipped with a transport pad at the tip of a transport arm that can rotate around an axis in the Z-axis direction and move up and down in the Z-axis direction, and is capable of suction and holding the upper surface of the workpiece 14. The second transport unit 45 suction and holds the upper surface of the workpiece 14 (in a state where rough grinding and finish grinding have been completed) on the holding table 13 positioned at the loading / unloading position with the transport pad, and operates the transport arm to place and transfer the workpiece 14 to the spinner table 46. The workpiece 14 is held by suction on the holding surface of the spinner table 46, and while the spinner table 46 is rotated, cleaning liquid is sprayed from the cleaning nozzle 47 toward the workpiece 14 to clean the workpiece 14 after processing. After cleaning, the workpiece 14 is dried by blowing air from the cleaning nozzle 47, and the transport robot 41 loads the cleaned workpiece 14 from the spinner table 46 and stores it in the cassette 48.

[0031] As described above, a series of processes are performed on the workpiece 14 in the processing device 10. The above explanation focused on the processing flow for one workpiece 14, but the processing device 10 can also perform rough grinding and finish grinding on two workpieces 14 simultaneously. Furthermore, it is possible to sequentially transport three or more workpieces 14 to the processing device 10 and perform a continuous process including rough grinding and finish grinding.

[0032] When processing a workpiece 14 with the processing device 10, it is required that the entire lower surface of the workpiece 14, which is the object to be held, be held in close contact with the holding surface 26 of the holding table 13. If the workpiece 14 is partially lifted away from the holding surface 26, problems may occur such as the inability to grind the entire workpiece 14 to a uniform thickness, or damage to the lifted portion of the workpiece 14 during grinding. As described above, the holding table 13 holds the workpiece 14 by suction by operating the suction source 30 and applying suction force to the porous plate 25. Therefore, in order to achieve stable holding of the workpiece 14 by the holding surface 26, the suction force from the suction source 30 must be applied evenly to the holding surface 26 (especially the inner upper surface 28 of the porous plate 25). However, if foreign matter such as processing debris generated when processing the workpiece 14 with the processing device 10 enters the interior (pores) of the porous plate 25 made of porous material and causes clogging, the suction holding performance of the workpiece 14 by the holding table 13 will decrease. For example, if the suction force in the outer peripheral region of the holding surface 26 is insufficient due to clogging of the porous plate 25, the edges of the workpiece 14 may easily lift away from the holding surface 26, potentially causing chipping or breakage of the edges. The diagnostic method of this disclosure, described below, detects with high accuracy whether or not clogging has occurred in the holding table 13.

[0033] [Fluid supply step] In the fluid supply step, a fluid that serves as an indicator for determining blockage in the holding table 13 is supplied to the holding surface 26 of the holding table 13. The fluid supplied in the fluid supply step is a fluid that can be imaged and detected in the imaging step and detection step described later, and specifically, is a liquid or a two-fluid mixture of liquid and gas. The liquid is, for example, pure water. As an example of a method of supplying fluid to the holding surface 26 in the fluid supply step, Figure 2 shows a configuration in which liquid is supplied from inside the holding table 13, and Figure 3 shows a configuration in which liquid is supplied from outside the holding table 13.

[0034] As shown in Figure 2, when supplying liquid to the holding surface 26 from inside the holding table 13, the on-off valve 36 is opened and liquid is discharged from the liquid supply source 32. At this time, the on-off valves 34 and 35 are set to closed, and suction from the suction source 30 and air supply from the air supply source 31 are not performed. The liquid discharged from the liquid supply source 32 is supplied to the porous plate 25 through the flow path 33, leaks onto the holding surface 26 through the pores in the porous plate 25, and forms a fluid layer Q that covers the holding surface 26.

[0035] Once a predetermined time has elapsed sufficient for the fluid layer Q to form, the on / off valve 36 is closed to stop the supply of liquid from the liquid supply source 32. As an example, the supply of liquid to the holding surface 26 in the fluid supply step is set to continue for about 5 seconds.

[0036] Alternatively, the amount of liquid discharged from the liquid supply source 32 may be monitored, and once a sufficient amount of liquid has been supplied to form the fluid layer Q, the on / off valve 36 may be closed to stop the discharge of liquid from the liquid supply source 32.

[0037] Alternatively, in the fluid supply step, the holding surface 26 may be imaged using an imaging unit capable of imaging the holding surface 26 (the imaging unit 72 used in the imaging step described later may also be used), and once it is confirmed from the image that the fluid layer Q has been formed, the system may control the flow of liquid from the liquid supply source 32 to stop. Since the reflectivity and refractive index of light differ between the state in which the holding surface 26 is exposed and the state in which the fluid layer Q has been formed on the holding surface 26, it is possible to determine whether or not the fluid layer Q has been formed by performing image processing such as binarization on the captured image.

[0038] Even if partial clogging occurs in the porous plate 25, preventing direct leakage of liquid from the inside of the porous plate 25 to a portion of the holding surface 26, or if the leakage time is longer than in other areas, it is still possible to form a fluid layer Q over the entire holding surface 26 by allowing the liquid supplied to other areas of the holding surface 26 to spread. In this case, the holding table 13 may be rotated at a low speed by the holding table rotation mechanism 29 to facilitate the spread of liquid over the holding surface 26 by centrifugal force.

[0039] In the fluid supply step, the on-off valve 35 may be opened simultaneously with the supply of liquid from the liquid supply source 32 to supply air from the air supply source 31, thereby supplying a two-fluid mixture of liquid and air (gas) to the porous plate 25. Even when the fluid layer Q formed on the holding surface 26 consists of two fluids, it can be used as a marker to determine clogging of the holding table 13. In other words, the fluid layer Q formed in the fluid supply step only needs to contain a liquid component that can be imaged (visualized) in the subsequent imaging step, and the fluid layer Q may consist only of liquid, or it may consist of two fluids.

[0040] As shown in Figure 3, when supplying liquid to the holding surface 26 from outside the holding table 13, a first configuration in which the liquid is supplied from the rough grinding mechanism 50 or the finish grinding mechanism 60, or a second configuration in which the liquid is supplied from the liquid supply nozzle 70 can be applied. Although Figure 3 shows both the configuration for the first configuration and the configuration for the second configuration, it is not necessary to have both configurations; it is sufficient to have at least one of them.

[0041] As described above, when processing the workpiece 14, liquid is supplied from the rough grinding mechanism 50 and the finish grinding mechanism 60 to cool the processing point and its surroundings and to clean the processing chips. The first form of external liquid supply is to apply the liquid supply from the rough grinding mechanism 50 and the finish grinding mechanism 60 to the fluid supply step of the diagnostic method. The configuration for liquid supply is common to both the rough grinding mechanism 50 and the finish grinding mechanism 60, and will be explained together with reference to Figure 3.

[0042] As shown in Figure 3, channels 58 and 68 are formed that pass through the spindles 52 and 62 and the grinding wheels 53 and 63, and liquid supplied from liquid supply sources 57 and 67 enters the channels 58 and 68 from the inlets on the upper ends of the spindles 52 and 62. The outlets of the channels 58 and 68 are supply ports 59 and 69, which are openings formed on the lower sides of the grinding wheels 53 and 63. Multiple supply ports 59 and 69 are formed at predetermined intervals in the circumferential direction of the grinding wheels 53 and 63, and each supply port 59 and 69 is located radially inward of the grinding wheels 53 and 63 compared to the annularly arranged rough grinding wheels 51 and finish grinding wheels 61. The liquid that exits the supply ports 59 and 69 through the channels 58 and 68 falls onto the holding surface 26 and spreads, forming a fluid layer Q that covers the holding surface 26. In order to facilitate the distribution of the liquid discharged from the supply ports 59 and 69 across the entire holding surface 26 during the formation of the fluid layer Q, the holding table 13 may be rotated by the holding table rotation mechanism 29, and the grinding wheels 53 and 63 may also be rotated.

[0043] Alternatively, the motors 56 and 66 may be used to rotate the ball screws 55 and 65 to position the rough grinding mechanism 50 and the finish grinding mechanism 60 at a height in the Z-axis direction suitable for forming the fluid layer Q, and then the liquid may be supplied from the supply ports 59 and 69. At a minimum, by positioning the rough grinding wheel 51 and the finish grinding wheel 61 so that they are not in close contact with the holding surface 26 but are separated upward, the fluid layer Q can be formed without being obstructed by the rough grinding wheel 51 and the finish grinding wheel 61.

[0044] A second configuration for supplying liquid from a liquid supply nozzle 70 will be described. As shown in Figure 3, the liquid supply nozzle 70 is connected to a liquid supply source 71. The liquid supply source 71 has a tank for storing liquid and a pump for dispensing liquid from the tank, and the liquid dispensed from the liquid supply source 71 is ejected from the tip of the liquid supply nozzle 70. In the fluid supply step, a fluid layer Q covering the holding surface 26 is formed by the liquid ejected from the liquid supply nozzle 70.

[0045] The liquid supply nozzle 70 may be provided at a position corresponding to the loading / unloading position of the holding table 13, the first processing position, or the second processing position. If the liquid supply nozzle 70 is provided at a position corresponding to the first or second processing position of the holding table 13, the liquid supply nozzle 70 can also be used as a means to supply liquid to the vicinity of the processing point where the rough grinding wheel 51 or the finish grinding wheel 61 contacts the workpiece 14 during processing. The liquid supply nozzle 70 is located on the outer circumference side of the rough grinding wheel 51 or the finish grinding wheel 61, and when processing the workpiece 14, the liquid sprayed from the liquid supply nozzle 70 can be used to cool the processing point and its surroundings and to clean processing chips.

[0046] If the liquid supply nozzle 70 is provided at a position corresponding to the loading / unloading position of the holding table 13, the configuration will differ from that shown in Figure 3, and the rough grinding mechanism 50 and the finish grinding mechanism 60 will not be positioned above the holding table 13. Since the workpiece 14 is not processed at the loading / unloading position of the holding table 13, the liquid supply nozzle 70 in this case may not have a structure that sprays liquid horizontally toward the processing point as shown in Figure 3, but rather a structure that drips liquid downward or diagonally downward toward the holding surface 26 (a dedicated structure specialized for forming the fluid layer Q).

[0047] In both the first configuration, where liquid is supplied from the rough grinding mechanism 50 and the finish grinding mechanism 60, and the second configuration, where liquid is supplied from the liquid supply nozzle 70, the supply of liquid from the liquid supply sources 57, 67, and 71 is stopped once a predetermined time has elapsed sufficient for the fluid layer Q to form. Alternatively, the amount of liquid supplied from the liquid supply sources 57, 67, and 71 may be monitored, and the supply of liquid from the liquid supply sources 57, 67, and 71 may be stopped once a sufficient amount of liquid has been supplied for the formation of the fluid layer Q. Alternatively, the holding surface 26 may be imaged using an imaging unit capable of imaging the holding surface 26 (the imaging unit 72 used in the imaging step described later may be used), and once it is confirmed by the image that the fluid layer Q has been formed, the supply of liquid from the liquid supply sources 57, 67, and 71 may be stopped.

[0048] If the porous plate 25 is significantly clogged, even if liquid or two fluids are supplied to the porous plate 25 from inside the holding table 13 via the flow path 33, the fluid layer Q may not be properly formed on the holding surface 26. Specifically, the fluid layer Q may be formed sparsely on the holding surface 26, or almost not formed at all. In such cases, the fluid layer Q can be reliably formed on the holding surface 26 by supplying liquid from outside the holding table 13 using the method shown in Figure 3. Note that when forming the fluid layer Q on the holding surface 26, two fluids may be supplied from outside the holding table 13 instead of liquid.

[0049] As described above, in the fluid supply step, a liquid or two fluids are supplied from inside or outside the holding table 13 to form a fluid layer Q on the holding surface 26. The fluid layer Q only needs to be such that the success or failure of suction to the porous plate 25 in the next suction step can be determined based on an image taken of the holding surface 26, and this determination is possible even if the fluid layer Q consists of a transparent liquid.

[0050] [Suction step] After the fluid supply step, a suction step is performed to suck the liquid supplied to the holding surface 26 of the holding table 13. As shown in Figure 4, in the suction step, the suction source 30 is operated to open the on-off valve 34 and suck the air in the porous plate 25 through the flow path 33. The on-off valves 35 and 36 are set to a closed state, so that air is not supplied from the air supply source 31 and liquid is not supplied from the liquid supply source 32. Once enough time has elapsed to suck the fluid layer Q, the on-off valve 34 is closed to stop the suction operation by the suction source 30. As an example, the suction in the suction step is set to continue for about 5 seconds.

[0051] If the porous plate 25 is free from blockages and the suction force can be applied evenly to the holding surface 26, then by performing the suction step, the liquid or two fluids forming the fluid layer Q will be sucked from the entire holding surface 26, and no fluid layer Q will remain on the holding surface 26. More specifically, no fluid layer Q will remain on the inner upper surface 28 of the holding surface 26. If there is a blockage in the porous plate 25, then when the suction step is performed, the liquid or two fluids will not be sucked in the area with the blockage and will remain on the holding surface 26. The portion of the fluid layer Q that remains on the holding surface 26 after the suction step is defined as the fluid residue region Q' (see Figures 4 and 6).

[0052] [Imaging step] After the suction step, an imaging step is performed to image the holding surface 26 of the holding table 13 and acquire an image. As shown in Figures 1 and 4, the processing apparatus 10 is equipped with an imaging unit 72 capable of imaging the holding surface 26. The imaging unit 72 shown in Figure 1 is positioned to image the holding surface 26 of the holding table 13 positioned at the loading / unloading position, and is attached to the tip of a movable arm that can rotate about an axis in the Z-axis direction. When the holding surface 26 is not being imaged, the movable arm can be operated to move the imaging unit 72 away from above the holding surface 26, so that the imaging unit 72 does not obstruct the loading and unloading of the workpiece 14 to and from the holding table 13. Alternatively, the imaging unit 72 may be supported to move in the Z-axis direction, and the imaging unit 72 may be moved upward (+Z direction) when not taking images. Note that the arrangement of the imaging unit 72 is not limited to that shown in Figure 1, and it may be arranged to image the holding surface 26 of the holding table 13 positioned at the first processing position or the second processing position.

[0053] Furthermore, the position of the holding table 13 performing the fluid supply step and the position of the holding table 13 performing the imaging step may be the same or different. For example, if the imaging unit 72 is positioned to image the holding surface 26 of the holding table 13 positioned at the loading / unloading position (i.e., the configuration shown in Figure 1), then with the holding table 13 at the loading / unloading position, liquid can be supplied to the holding surface 26 from the liquid supply source 32 or liquid supply nozzle 70 (Figure 3) to form a fluid layer Q (performing the fluid supply step), the holding table 13 can then be moved to the loading / unloading position, the suction step can be performed, and then the imaging unit 72 can image the holding surface 26 (performing the imaging step). In this case, the holding table 13 remains at the loading / unloading position from the fluid supply step to the imaging step.

[0054] As an example of how the holding table 13 is moved between the fluid supply step and the imaging step, it is possible to form a fluid layer Q on the holding surface 26 by supplying liquid from the rough grinding mechanism 50 at the first processing position of the holding table 13, or by supplying liquid from the finish grinding mechanism 60 at the second processing position of the holding table 13 (performing the fluid supply step), performing the suction step, and then rotating the turntable 21 to move the holding table 13 to the loading / unloading position, after which the holding surface 26 is imaged by the imaging unit 72 (performing the imaging step).

[0055] Furthermore, to prevent the loss of the fluid layer Q and fluid residue area Q' due to natural drying, it is desirable to complete the suction step and imaging step within a predetermined time from the fluid supply step. In particular, if the turntable 21 is rotated to move the holding table 13 between the fluid supply step and the imaging step, a time lag will occur before the imaging step is performed, so care must be taken to prevent the loss of the fluid layer Q and fluid residue area Q' due to natural drying.

[0056] In the imaging step, imaging is performed such that the imaging range includes the inner upper surface 28, which is the upper surface of the porous plate 25, of the holding surface 26. If the field of view that the imaging unit 72 can image is only a part of the holding surface 26, it is desirable to move the imaging unit 72 and the holding table 13 relative to each other to image the entire circumferential surface of the holding surface 26. This is because clogging of the porous plate 25 does not necessarily occur uniformly across the entire circumferential surface of the holding surface 26, and if only a part of the circumferential direction is imaged, there is a possibility of missing an abnormality in the holding table 13. As a method of moving the imaging unit 72 and the holding table 13 relative to each other, it is preferable to operate the holding table rotation mechanism 29 to rotate the holding table 13 once while the imaging unit 72 is held in a fixed position relative to the holding surface 26. This allows the entire circumferential surface of the holding surface 26 to be imaged in a short time. Alternatively, the imaging unit 72 may be supported so as to be movable in the horizontal direction, and the entire circumferential surface of the holding surface 26 may be imaged by moving the imaging unit 72 in the circumferential direction of the holding surface 26. If the imaging unit 72 is equipped with a wide-angle optical system, the entire holding surface 26 may be imaged at once during the imaging step without relative movement between the imaging unit 72 and the holding table 13.

[0057] It is not essential to image the entire radial region of the holding surface 26; it is also possible to image only specific radial regions where clogging of the holding table 13 is likely to occur. When grinding a workpiece 14 with the processing device 10, foreign matter is less likely to enter the porous plate 25 in the central region of the holding surface 26 covered by the workpiece 14, while foreign matter tends to enter and clog the porous plate 25 in the outer peripheral region of the holding surface 26 located outside the outer edge of the workpiece 14. For example, as shown in Figure 6, the outer peripheral portion of the inner upper surface 28, closer to the annular upper surface 27, is a common location for clogging of the porous plate 25, i.e., a location where a fluid residue region Q' is likely to exist after the suction step. Therefore, when imaging a part of the radial region of the holding surface 26 in the imaging step, it is preferable to image only the outer peripheral region excluding the central region of the holding surface 26, thereby efficiently detecting clogging of the porous plate 25. In this case, by positioning the imaging unit 72 above the outer peripheral region of the holding surface 26 and rotating the holding table 13 relative to the imaging unit 72, an image of one full rotation of the outer peripheral region of the holding surface 26 can be acquired in a short time.

[0058] [Detection step] Next, a detection step is performed in which the image captured in the imaging step is processed to detect areas where liquid remains as an anomaly. The control unit 15 includes an image processing unit 73 and a detection unit 74 as functional blocks (see Figure 1). The image processing unit 73 performs image processing, and the detection unit 74 detects an anomaly on the holding surface 26 based on the residual liquid or two fluids after the suction step from the processed image.

[0059] The image processing performed by the image processing unit 73 is a process that enhances the contrast between the holding surface 26 (especially the inner upper surface 28) and the fluid residue region Q', for example, a binarization process. When the imaging unit 72 performs imaging in the visible light region, the fluid residue region Q' has a lower brightness than the holding surface 26 and tends to appear darker. Therefore, when the image is binarized, the inner upper surface 28 of the holding surface 26 is displayed in white and the fluid residue region Q' is displayed in black.

[0060] The detection unit 74 performs a process to detect abnormalities in areas where a fluid residue region Q' is visible, i.e., areas where liquid or two fluids remain, based on the image processed by the image processing unit 73. Figure 5 shows an image obtained after the suction step followed by the imaging step, where there is no fluid residue region Q' on the holding surface 26. In this case, the detection unit 74 determines that there is no abnormality. Figure 6 shows an image obtained after the suction step followed by the imaging step, where there is a fluid residue region Q' on the holding surface 26 (where liquid or two fluids remain). When a fluid residue region Q' like the one in Figure 6 is present, the detection unit 74 determines that there is an abnormality.

[0061] When only the outer peripheral region of the holding surface 26 is targeted for detection in the detection step, the range of the outer peripheral region (the radial region of the holding surface 26) for determining the presence or absence of the fluid residue region Q' can be set arbitrarily. As an example, if the fluid residue region Q' exists with a width of 1 to 1.5 mm or more from the outer edge of the inner upper surface 28 (the boundary between the annular upper surface 27 and the inner upper surface 28) toward the radial center of the inner upper surface 28, it is determined to be abnormal.

[0062] Furthermore, as shown in Figure 6, during the detection step, one or more fluid residue regions Q' may exist partially (discontinuously) in the circumferential direction of the holding surface 26. Even if it is only a partial area in the circumferential direction, if clogging occurs in the porous plate 25, it can cause the edges of the workpiece 14 in that area to lift, so it is desirable to determine this as an abnormality in the detection step.

[0063] If the detection step targets the entire holding surface 26, including not only the outer peripheral region but also the central region, a predetermined threshold can be set for the area of ​​the fluid residue region Q' on the holding surface 26. Even if a fluid residue region Q' exists, if its area is less than the threshold, it will not be judged as abnormal (it will be determined that there is no impairment to the practical suction performance). For example, as shown in Figure 6, if the fluid residue region Q' extends circumferentially around the holding surface 26, it will be judged as abnormal, but if it is an extremely small, spot-like fluid residue region, it will not be judged as abnormal as long as its size does not exceed the threshold.

[0064] Furthermore, if multiple fluid residue regions Q' exist, the ratio of the total area of ​​the fluid residue regions Q' to the area of ​​the inner upper surface 28 on the holding surface 26 may be detected. If the ratio of the total area of ​​the fluid residue regions Q' is greater than or equal to a threshold, it may be determined that there is an abnormality, and if the ratio of the total area of ​​the fluid residue regions Q' is less than the threshold, it may be determined that there is no abnormality.

[0065] Furthermore, it is possible to differentiate the weighting of detection decisions regarding the fluid residue area Q' between the outer peripheral region and the central region of the holding surface 26. For example, in the outer peripheral region, where damage to the edges of the workpiece 14 is likely to occur, even a minute fluid residue area Q' may be judged as abnormal, while in the central region, a fluid residue area Q' that is slightly larger than that in the outer peripheral region may not be judged as abnormal.

[0066] If the detection unit 74 detects an abnormality, the control unit 15 performs a process to notify the abnormality of the holding table 13 via the notification unit (display monitor, indicator lamp, speaker, etc.) of the processing device 10 or via communication equipment (server, personal computer, tablet computer, smartphone, etc.) that can communicate with the processing device 10.

[0067] As described above, in areas where the porous plate 25 is clogged, the liquid or two-fluid mixture is not sucked from the holding surface 26 during the suction step and remains. Therefore, most of the abnormalities detected by the detection unit 74 in the detection step are due to clogging of the porous plate 25. The holding table 13 is equipped with an internal cleaning function that supplies two-fluid mixtures to the porous plate 25 by sending air from the air supply source 31 and liquid from the liquid supply source 32. The internal cleaning operation is performed periodically, using the pressure of the supplied two-fluid mixture to push foreign matter inside the porous plate 25 onto the holding surface 26. In addition, superficial clogging of the holding surface 26 can sometimes be resolved by self-grinding, which involves grinding the inner upper surface 28 of the porous plate 25 with a grinding wheel to adjust the shape of the holding surface. However, even after performing such normal maintenance, if residual liquid or two-fluid mixtures are detected on the holding surface 26 in the detection step, it is assumed that foreign matter has penetrated deep into the porous plate 25 and cannot be removed. In this condition, it becomes necessary to remove the holding table 13 for disassembly and cleaning, or to replace the porous plate 25. Therefore, the control unit 15 may recommend replacing the holding table 13 as part of the notification regarding the abnormality of the holding table 13.

[0068] However, suction abnormalities in the holding table 13 may occur due to causes other than clogging of the porous plate 25. For example, suction failure may be caused by a malfunction of the suction source 30 or the on / off valve 34, or by a leak in the flow path 33. Abnormalities in the holding table 13 caused by such reasons can also be detected in the detection step.

[0069] An example of a diagnostic method including each of the above steps will be explained with reference to the flowchart in Figure 7. In the flowchart in Figure 7, "fluid" refers to a liquid or a two-fluid system. In this example, the processing apparatus 10 is equipped with a structure that supplies fluid to the holding surface 26 from inside the holding table 13 (see Figure 2) and a structure that supplies fluid to the holding surface 26 from outside the holding table 13 (see Figure 3), and the use of these fluid supply structures can be selected as appropriate.

[0070] The control unit 15 receives a signal to transition to diagnostic mode for diagnosing the holding table 13, which initiates the process shown in Figure 7. The transition to diagnostic mode may be performed at any time by the operator, or it may be performed automatically when the processing device 10 is started up or after a predetermined usage time has elapsed.

[0071] In step 100, liquid or two fluids are supplied from inside the holding table 13 to the holding surface 26. If there are no problems such as significant clogging of the porous plate 25, a fluid layer Q is formed on the holding surface 26 by the supply of liquid or two fluids from inside.

[0072] In step 101, it is determined whether or not a fluid layer Q is properly formed on the holding surface 26. For example, the holding surface 26 can be imaged by the imaging unit 72, and the formation of the fluid layer Q can be determined based on the image. If the imaging unit 72 is not a wide-angle camera, the holding table 13 and the imaging unit 72 can be moved relative to each other by using the holding table rotation mechanism 29 to image a wide area of ​​the holding surface 26 and determine the presence or absence of the fluid layer Q.

[0073] If the determination in step 101 indicates that the fluid layer Q is properly formed on the holding surface 26 (YES in step 101), the process proceeds to step 103. If the determination in step 101 indicates that the fluid layer Q is not properly formed on the holding surface 26 (NO in step 101), the process proceeds to step 102, in which liquid or two fluids are supplied to the holding surface 26 from outside the holding table 13. Then, the process proceeds to step 103. Steps 100 to 102 correspond to the fluid supply step described above.

[0074] In the flowchart of Figure 7, the process proceeds from step 102 to step 103, based on the assumption that the fluid layer Q is reliably formed by the fluid supply from outside the holding table 13. However, considering the possibility of errors occurring during the formation of the fluid layer Q using the fluid supply from outside the holding table 13, it may be possible to return to step 101 after step 102 to check the formation of the fluid layer Q again. If the formation of the fluid layer Q cannot be detected even after the second check, it may be determined that the holding table 13 cannot be diagnosed, and the process may be exited from the process shown in Figure 7.

[0075] Step 103 corresponds to the suction step described above. In step 103, the liquid or two fluids on the holding surface 26 are suctioned, and the process proceeds to step 104.

[0076] Step 104 corresponds to the imaging step described above. In step 104, the holding surface 26 is imaged to acquire an image, and the process proceeds to step 105.

[0077] In step 105, the captured image is processed by the image processing unit 73, and based on the processed image, the detection unit 74 detects the fluid residue area Q' on the holding surface 26. Then, based on the detection result, in step 106, it is determined whether or not there is any residual liquid or two fluids on the holding surface 26. Steps 105 and 106 correspond to the detection steps described above.

[0078] If the detection results show that no liquid or two fluids are present on the holding surface 26 (NO in step 106), the diagnosis is that there is no abnormality in the suction holding performance of the holding table 13, and the flowchart in Figure 7 is exited. Note that after proceeding to NO in step 106, a step to notify the system of the diagnosis of "no abnormality" may be included.

[0079] If the detection results in a residual fluid area Q' of liquid or two fluids on the holding surface 26 (YES in step 106), the diagnosis is that there is an abnormality in the suction holding performance of the holding table 13, and the process proceeds to step 107. Alternatively, as described above, a predetermined threshold can be set for the area of ​​the residual fluid area Q' on the holding surface 26, and if the area is less than the threshold, it may not be judged as abnormal. In step 107, any abnormality response processing is performed, such as notification by the notification unit described above. After the execution of step 107, the process exits the flowchart in Figure 7.

[0080] As described above, according to the diagnostic method for the holding table of this embodiment, a liquid or two fluids are supplied to the holding surface 26 of the holding table 13, and then the liquid or two fluids are aspirated. Based on the image of the holding surface after aspiration, the presence or absence of an abnormality in the holding table is detected. Since the presence or absence of an abnormality is determined by imaging the holding surface 26 after aspiration has been performed, rather than at the stage when the liquid or two fluids are supplied to the holding surface 26, it is possible to accurately detect the status of the suction holding performance of the holding table 13.

[0081] Unlike this embodiment, if the liquid or two-fluid mixture supplied from inside the holding table 13 to the holding surface 26 is imaged directly, the information may not accurately reflect the localized suction state (area where suction is possible) on the holding surface 26 due to reasons such as the liquid or two-fluid mixture spreading on the holding surface 26. In other words, an abnormality cannot be detected unless there is a sufficiently large blockage in the porous plate 25, and there is a risk that the accuracy required to detect localized or minute blockages in the porous plate 25 cannot be obtained. In contrast, in the diagnostic method for the holding table according to this embodiment, the liquid or two-fluid mixture is spread throughout the area of ​​the holding surface 26 to be detected, suction is performed, and then the area of ​​the holding surface 26 is imaged to detect an abnormality. Therefore, information that accurately reflects the success or failure of suction on the holding surface 26 can be obtained. In particular, the state after aspirating the liquid or two-fluid mixture, compared to the state immediately after supplying the liquid or two-fluid mixture from inside the holding table 13 to the holding surface 26, shows a reduction in the excess amount and spread of the liquid or two-fluid mixture, and the traces of aspiration are clearly indicated. Therefore, the diagnostic method of this embodiment has the advantage of being able to precisely detect even localized or minute blockages in the porous plate 25, and thus obtain highly accurate diagnostic results.

[0082] Furthermore, if the holding table 13 is severely clogged, even if liquid or two fluids are supplied from inside the holding table 13 toward the holding surface 26 to detect the clogged state, the supply itself may be obstructed, making it impossible to perform an accurate diagnosis. In contrast, the method for diagnosing the holding table according to this embodiment makes a judgment based on the results of suction after supplying the liquid or two fluids, regardless of how the liquid or two fluids are supplied to the holding surface 26. Therefore, by switching to supplying the liquid or two fluids from outside the holding table 13, this problem can be avoided, and abnormalities in the holding table can be reliably detected.

[0083] In the above embodiment, the fluid layer Q is formed evenly across the entire surface of the holding surface 26. However, if only the outer peripheral region of the holding surface 26 is imaged in the imaging step, excluding the central region, and abnormalities are detected only in the outer peripheral region in the detection step, the fluid layer may be formed only in the outer peripheral region of the holding surface 26 (the region included in the imaging range in the imaging step). For example, unlike the liquid supply nozzle 70 shown in Figure 3, a liquid supply nozzle with a structure that drops liquid downward or diagonally downward toward the holding surface 26 can be used. By positioning the liquid supply nozzle above the outer peripheral region of the holding surface 26 and dropping the liquid, while rotating the holding table 13 with the holding table rotation mechanism 29, a fluid layer can be formed only in the outer peripheral region of the holding surface 26. Forming a fluid layer only in the outer peripheral region of the holding surface 26 reduces the amount of liquid or two fluids supplied, thus saving resources.

[0084] The holding table 13 in the above embodiment has a structure in which one porous plate 25 is placed in a recess 24 of the frame 23. However, it may also have a structure in which multiple porous plates are placed in the recess of the frame, and the spaces between each porous plate are partitioned so that fluid cannot pass through. For example, a holding table is known in which a substantially circular porous plate is placed in the center of the recess of the frame, and at least one annular porous plate is placed concentrically around it. The present invention can also be applied to the diagnosis of a holding table of such a structure. In this case, it is possible to select the area to which the suction force is applied on a per-porous plate basis, and to apply the above diagnostic method to each individual porous plate.

[0085] The holding table 13 in the above embodiment is equipped with a porous plate 25 made of a porous material to apply suction force to the entire inner upper surface 28. However, this method can also be applied to the diagnosis of a holding table in which grooves or suction holes for suction are partially formed on the holding surface instead of the porous plate 25.

[0086] The above embodiment is applied to the holding table 13 of a grinding machine 10. Normally, during grinding, the object to be held is held so that it does not protrude outside the holding surface of the holding table. As a result, clogging of processing debris and other materials is likely to occur in the outer peripheral region of the holding surface that is outside the outer edge of the object to be held. Therefore, there is a high demand for accurately diagnosing abnormalities such as clogging in the holding table that holds the object to be held during grinding, and the diagnostic method for the holding table according to the present invention is highly useful. However, the application of the present invention is not limited to grinding machines, and it can also be applied to the diagnosis of holding tables that hold objects when performing various other processes (e.g., polishing, cutting, laser processing, etc.).

[0087] Furthermore, the diagnostic method of the present invention can also be applied to holding tables that hold objects during processes other than machining. For example, the spinner table 46 shown in Figure 1 holds the workpiece 14 by suction when cleaning the workpiece 14. When the workpiece 14 after grinding is transported to the spinner table 46, if dirt such as liquid containing machining debris adheres to the underside of the workpiece 14, the dirt on the underside of the workpiece 14 will be sucked into the spinner table 46, causing it to clog. Therefore, there is a need to accurately diagnose abnormalities such as clogging in the spinner table 46 as well, and the present invention is applicable to this as well. In the case of the spinner table 46, the fluid supply step can be performed using the fluid supply from the cleaning nozzle 47. Furthermore, if the temporary storage table 42 shown in Figure 1 has a structure that holds the workpiece 14 by suction on its holding surface, the diagnostic method of the present invention may also be applied to the temporary storage table 42.

[0088] Furthermore, the present invention is not limited to stationary processing and processing equipment, but can also be applied to diagnostics of holding tables in conveying equipment that transports objects while holding them by suction.

[0089] In the method for processing the workpiece, after diagnosing the holding table using the diagnostic method described above, the workpiece is held in the holding table, and a processing step is performed to process the workpiece on the holding table using an arbitrary processing unit. The holding table used to hold the workpiece in the processing step is a holding table that was not determined to be abnormal in the detection step of the diagnostic method described above, or a holding table that was determined to be abnormal in the detection step of the diagnostic method described above, but has since been replaced or maintained to resolve the abnormality. In other words, a holding table without abnormalities is used in the processing step.

[0090] The processing performed on the workpiece in the processing step can vary. For example, both processing methods that change the properties or shape of the workpiece, such as grinding, polishing, cutting, and laser processing, and processing methods that do not change the properties or shape of the workpiece, such as inspection, imaging, and transport, are included in the scope of processing performed in the processing step. When processing is performed on a workpiece, it can also be applied as a manufacturing method for producing the product obtained as a result of the processing. Cleaning can involve removing protective members attached to the workpiece, which significantly changes its shape, or simply removing debris from the workpiece without significantly changing its shape. In either case, it is included in the scope of processing performed in the processing step.

[0091] In the case of the processing apparatus 10 of the above embodiment, the processing step involves holding the workpiece 14, which is the work to be processed, in the holding table 13, which has been diagnosed and found to have no abnormalities in suction holding performance, and grinding the workpiece 14 using the processing units, namely the rough grinding mechanism 50 and the finish grinding mechanism 60. In other words, when the above diagnostic method is applied to the holding table 13, the processing step performed in the processing apparatus 10 involves grinding the workpiece 14 and producing a product that has been thinned by grinding. This product may be an intermediate product before it becomes a product that is ultimately distributed in the market. For example, this can also be applied when the workpiece 14 is a semiconductor wafer with multiple chips, and the workpiece 14 (intermediate product) after grinding in the processing apparatus 10 is divided along a planned division line in a processing apparatus other than the processing apparatus 10 to produce multiple chips (final products).

[0092] The processing step in the processing apparatus 10 may involve holding the workpiece 14, which is the object to be processed, on the spinner table 46, which has been diagnosed and found to have no abnormalities in suction holding performance, and cleaning the workpiece 14 using the cleaning nozzle 47 that constitutes the processing unit. Alternatively, the processing step may involve holding the workpiece 14, which is the object to be processed, on the temporary placement table 42, which has been diagnosed and found to have no abnormalities in suction holding performance, and positioning the workpiece 14 using the positioning pin 43 that constitutes the processing unit.

[0093] Furthermore, the embodiments of the present invention are not limited to the embodiments and modifications described above, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Moreover, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial applicability]

[0094] According to the present invention, the condition of the holding table can be accurately diagnosed, contributing to the proper holding of objects in various devices. [Explanation of symbols]

[0095] 10: Processing equipment 11: Rough grinding mechanism 12: Finishing grinding mechanism 13: Holding Table 14: Workpiece (object to be held, object to be processed) 15: Control Unit 21: Turntable 23:Frame body 24: Recess 25: Porous board 26: Holding surface 27: Annular upper surface 28:Inner top surface 30: Suction source 31: Air supply source 32 :Liquid supply source 33: Flow path 34: Shut-off valve 35: Shut-off valve 36: Shut-off valve 41: Transport robot 42: Temporary Table 44: First Conveyor Department 45: Second Conveyor Unit 46: Spinner Table 47: Cleaning nozzle 50: Rough grinding mechanism (processing unit) 51: Coarse grinding wheel 53: Grinding Wheel 57 :Liquid supply source 58: Flow channel 59: Supply port 60: Finishing grinding mechanism (processing unit) 61: Finishing grinding wheel 63: Grinding Wheel 67 :Liquid supply source 68: Flow channel 69: Supply port 70: Liquid supply nozzle 71 :Liquid supply source 72: Imaging Unit 73: Image Processing Unit 74: Detection unit Q:Fluid layer Q' :Fluid residual area

Claims

1. A diagnostic method for diagnosing the state of a holding table, A fluid supply step involves supplying a liquid, or a mixture of liquid and gas, to the holding surface of a holding table having a holding surface for holding an object to be held. Following the fluid supply step, a suction step is performed to suction the liquid or the two fluids supplied to the holding surface, After the suction step, an imaging step is performed to capture an image of the holding surface, A detection step of processing the image to detect areas where the liquid or the two fluids remain as abnormalities, A diagnostic method for a storage table that includes the following features.

2. The diagnostic method for a retaining table according to claim 1, characterized in that the imaging step images only the outer peripheral region excluding the central region of the retaining surface.

3. A fluid supply step of supplying a liquid, or a mixture of liquid and gas, to the holding surface of a holding table having a holding surface, Following the fluid supply step, a suction step is performed to suction the liquid or the two fluids supplied to the holding surface, After the suction step, an imaging step is performed to capture an image of the holding surface, A detection step of processing the image to detect areas where the liquid or the two fluids remain as abnormalities, Following the detection step, a processing step is performed in which the object to be processed is held in the holding table that is free of abnormalities, and the object to be processed is processed by an arbitrary processing unit. A method for processing an object to be processed, comprising the following components.

4. The method for processing an object to be processed according to claim 3, characterized in that the processing step involves processing the object to be processed.

Images