Processing method, method for creating judgment conditions, and processing apparatus

Abstract

This invention provides a new method that can appropriately detect whether or not an abnormality has occurred during processing. [Solution] A machining device is provided in which determination conditions for diagnosing the state during machining are stored in memory, which are created by classifying the first machining information according to the first load value, based on a first load value applied to the first workpiece or the first machining tool and first machining information other than the first load value related to the machining of the first workpiece, obtained during machining of the first workpiece with the first machining tool, and the machining method is provided comprising: machining a second workpiece with a second machining tool; acquiring a second load value applied to the second workpiece or the second machining tool and second machining information other than the second load value related to the machining of the second workpiece during machining of the second workpiece with the second machining tool; and diagnosing the state of machining of the second workpiece with the second machining tool according to the determination conditions for the first load value corresponding to the second load value.

Description

Technical Field

[0001] The present invention relates to a processing method for processing a workpiece with a processing tool, a method for creating determination conditions, and a processing apparatus for processing a workpiece.

Background Art

[0002] In the manufacturing process of semiconductor devices, a workpiece such as a semiconductor wafer may be polished with a polishing pad. In polishing, if abrasion of the polishing tool, sudden change in processing load, or other abnormalities occur, the workpiece may not be properly processed.

[0003] Therefore, conventionally, a skilled operator has judged the occurrence of an abnormality by a method of distinguishing the sound during processing. However, the method of distinguishing the sound during processing has problems that it requires a skilled operator, so the number of operators is very limited, and there is also a problem that the judgment varies based on the senses.

[0004] On the other hand, there is also a method of judging the occurrence of an abnormality by monitoring the value of the current flowing through a motor for rotating a spindle to which a tool is attached (that is, the spindle current value) (for example, see Patent Document 1).

[0005] However, during the period from the start to the end of processing of a single workpiece, the spindle current value generally tends to increase as it approaches the end of processing. Therefore, it is not always appropriate to judge that an abnormality in processing has occurred based on the criterion of whether the spindle current value exceeds a predetermined threshold value.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] This invention has been made in view of the aforementioned problems, and aims to provide a new method that can appropriately detect whether or not a processing abnormality has occurred. [Means for solving the problem]

[0008] According to one aspect of the present invention, a machining method for machining a workpiece with a machining tool is provided, comprising: a machining device in which determination conditions for diagnosing the state during machining are stored in memory, which are created by classifying the first machining information according to the first load value, based on a first load value obtained during machining of a first workpiece with a first machining tool, and first machining information other than the first load value relating to the machining of the first workpiece; machining a second workpiece with a second machining tool; acquiring a second load value applied to the second workpiece or the second machining tool, and second machining information other than the second load value relating to the machining of the second workpiece, during machining of the second workpiece with the second machining tool; and diagnosing the state of machining of the second workpiece with the second machining tool according to the determination conditions for the first load value corresponding to the second load value.

[0009] Preferably, storing the determination conditions in the memory includes classifying the data, which includes the first load value and the first processing information obtained when the first workpiece is processed, into a plurality of groups according to the first load value, and creating the determination conditions for each group based on the data classified into the plurality of groups.

[0010] Preferably, storing the determination conditions in the memory of the processing apparatus includes selecting and retaining a portion of the data to be used when classifying it into the plurality of groups, before classifying the data into the plurality of groups.

[0011] Preferably, the first machining tool and the second machining tool each have polishing pads, the determination condition is obtained when polishing one surface of the first workpiece with the first machining tool, and when diagnosing the state of the second workpiece during machining, one surface of the second workpiece is polished with the second machining tool, and the state of the second workpiece during polishing with the second machining tool is diagnosed according to the determination condition.

[0012] According to another aspect of the present invention, a method for creating determination conditions is provided, comprising: classifying data, which includes load values ​​applied to the workpiece or the processing tool and processing information other than the load values ​​related to the processing of the workpiece, obtained during the processing of the workpiece with the processing tool, into a plurality of groups according to the magnitude of the load values; and creating determination conditions for each group to diagnose the state of the workpiece during processing, based on the data classified into the plurality of groups.

[0013] According to yet another aspect of the present invention, a processing apparatus for processing a workpiece comprises a holding table for holding the workpiece, a spindle on which a processing tool is mounted, and a controller having a processor and memory for controlling the operation of the holding table and the spindle, wherein the memory contains a first load value obtained during the processing of the first workpiece with the first processing tool, applied to the first workpiece or the first processing tool, and first processing information other than the first load value relating to the processing of the first workpiece, and according to the first load value A processing device is provided in which a controller stores judgment conditions for diagnosing the state during processing, which are created by classifying the first processing information, and the controller acquires a second load value applied to the second workpiece or the second processing tool, and second processing information other than the second load value related to the processing of the second workpiece, while the second workpiece is being processed by the second processing tool mounted on the spindle, and diagnoses the state of the second workpiece during processing by the second processing tool according to the judgment conditions for the first load value corresponding to the second load value. [Effects of the Invention]

[0014] In one aspect of the present invention, a processing device is used in which a second workpiece is processed with a second processing tool. This device is used to process a first workpiece with a second processing tool. First, a second workpiece is processed with a second processing tool in a processing device in which a determination condition for diagnosing the processing state is stored in memory, created by classifying the first processing information according to the first load value, based on a first load value obtained during the processing of the first workpiece with the first processing tool, and first processing information other than the first load value related to the processing of the first workpiece.

[0015] Furthermore, during machining of the second workpiece with the second machining tool, a second load value applied to the second workpiece or the second machining tool, and second machining information other than the second load value related to the machining of the second workpiece are acquired. Then, according to the judgment conditions for the first load value corresponding to the second load value, the state of the second workpiece during machining with the second machining tool is diagnosed.

[0016] In this way, by using judgment conditions set individually according to the load value, it is possible to detect whether or not a machining abnormality has occurred more appropriately than when detecting a machining abnormality based solely on whether or not the spindle current value exceeds a threshold.

[0017] Another aspect of the present invention relates to a method for creating determination conditions, which includes classifying data obtained during machining of a workpiece with a machining tool, including load values ​​applied to the workpiece or the machining tool, and machining information other than load values ​​related to the machining of the workpiece, into multiple groups according to the magnitude of the load values, and creating determination conditions for each group based on the data classified into multiple groups, for diagnosing the state of the workpiece during machining. By diagnosing the state of the second workpiece during machining with a second machining tool according to these determination conditions, it is possible to more appropriately detect whether or not a machining abnormality has occurred.

[0018] Further, in the processing apparatus according to still another aspect of the present invention, during the processing of the second workpiece with the second processing tool, the controller of the processing apparatus acquires a second load value applied to the second workpiece or the second processing tool and second processing information other than the second load value related to the processing of the second workpiece, and diagnoses the state during the processing of the second workpiece with the second processing tool according to the determination condition at the first load value corresponding to the second load value. Therefore, it is possible to more appropriately detect whether or not an abnormality in processing has occurred.

Brief Description of the Drawings

[0019] [Figure 1] It is a flowchart of a processing method. [Figure 2] It is a flowchart showing a method of storing determination conditions in the memory of a polishing apparatus. [Figure 3] It is a partial cross-sectional side view of a chuck table and a polishing unit. [Figure 4] It is a top view of a chuck table and a polishing unit. [Figure 5] FIG. 5(A) is an example of a screen showing the whole data before selectively leaving, and FIG. 5(B) is an example of a screen showing the data included in the processing ID number 1. [Figure 6] It is an example of a screen showing the whole data selectively left. [Figure 7] FIG. 7(A) is an example of a screen showing an example of data classified into group 1, FIG. 7(B) is an example of a screen showing an example of data classified into group 2, and FIG. 7(C) is an example of a screen showing an example of data classified into group 300. [Figure 8] It is a diagram showing an example of determination conditions for group 1. [Figure 9] It is a diagram showing an example of the acquired second processing information. [Figure 10] It is a flowchart showing a method of diagnosing the state during the processing of a wafer. [Figure 11] It is a scatter diagram showing the quality of surface burning with the load value (horizontal axis) and load 3 (vertical axis). [Figure 12]This scatter plot shows the quality of surface burning using load values ​​(horizontal axis) and spindle current values ​​(vertical axis). [Figure 13] This is a scatter plot showing load values ​​(horizontal axis) and load 3 (vertical axis) according to the presence or absence of edge chipping. [Figure 14] This is a scatter plot showing load values ​​(horizontal axis) and spindle current values ​​(vertical axis) according to the presence or absence of edge chipping. [Modes for carrying out the invention]

[0020] An embodiment of one aspect of the present invention will be described with reference to the attached drawings. Figure 1 is a flowchart of a processing method in which a wafer (i.e., a workpiece or a second workpiece) 11 (see Figure 3) is processed with a polishing tool 50 (see Figure 3).

[0021] In this embodiment, as shown in Figure 1, the determination conditions are stored in the memory 54b of the polishing device 2 (see Figure 3) (S10), the wafer 11 is processed with the polishing tool 50, and the load value (i.e., second load value) and processing information (i.e., second processing information) are acquired, and the state of the wafer 11 during processing is diagnosed (S20).

[0022] As shown in Figure 2, storing the judgment conditions in the memory 54b of the polishing apparatus 2 (S10) includes the steps of preparing the data acquired when the wafer (i.e., the first workpiece) 11 was processed (S12), selecting and retaining some of the data to be used when classifying the data into multiple groups (S14), classifying the selected data into multiple groups according to the load value (S16), and creating judgment conditions for each group (S18).

[0023] First, with reference to Figures 3 and 4, the polishing apparatus (i.e., processing apparatus) 2 for polishing (i.e., processing) the wafer 11 will be described. Figure 3 is a partial cross-sectional side view of the chuck table 12 and the polishing unit 30, and Figure 4 is a top view of the chuck table 12 and the polishing unit 30. Note that in Figure 3, some of the components are shown as functional blocks. The arrow shown as the Z-axis in Figures 3 and 4 indicates the upward direction and is parallel to the vertical direction.

[0024] The chuck table (i.e., holding table) 12 is disc-shaped. The upper surface of the chuck table 12 (i.e., the holding surface 12a) protrudes slightly from the center (for example, by about 10 μm to 30 μm) compared to the outer edge, but in Figure 3, this protrusion is exaggerated.

[0025] The chuck table 12 has a non-porous, dense, disc-shaped frame made of ceramics such as alumina. A disc-shaped recess is provided in the center of the frame. A porous plate made of ceramics such as alumina is placed in this recess. The porous plate is fixed to the frame via an adhesive or the like.

[0026] The upper surfaces of the frame and the porous plate are substantially flush and constitute the holding surface 12a. A suction source (not shown), such as a vacuum pump, is connected to the frame via a rotary joint (not shown). When negative pressure is transmitted from the suction source to the holding surface 12a, the wafer 11 placed on the holding surface 12a is held in place by suction.

[0027] The chuck table 12 is mounted on a disc-shaped table base 14. The table base 14 is rotatably supported by an air bearing 16. The air bearing 16 has a rotor 16a and a stator 16b.

[0028] The rotor 16a has a disc-shaped large-diameter portion 16a1 and a cylindrical small-diameter portion 16a2 arranged concentrically directly below the large-diameter portion 16a1. A ring-shaped stator 16b is positioned below the large-diameter portion 16a1 and around the small-diameter portion 16a2.

[0029] The rotor 16a and the stator 16b are not in contact, and a small gap (not shown) is formed between them. This gap is formed by the supply of compressed air from an air supply source (not shown).

[0030] A driven pulley (not shown) is fixed to the lower end of the small-diameter portion 16a2 of the rotor 16a. A first motor 18, such as a servo motor, is provided near the small-diameter portion 16a2. A drive pulley (not shown) is fixed to the output shaft of the first motor 18, and an endless belt (not shown) is stretched over both the drive pulley and the driven pulley.

[0031] When the first motor 18 is operated, rotational power is transmitted to the rotor 16a. In Figure 3, the power transmission is simply shown with arrows. The rotor 16a rotates while maintaining a non-contact state with the stator 16b. The rotation of the rotor 16a causes the chuck table 12 to rotate.

[0032] The stator 16b is supported by an annular table base 20. A through hole 20a is formed in the radial center of the table base 20. A small-diameter portion 16a2 is inserted into the through hole 20a in a manner that does not contact the table base 20.

[0033] Multiple disc-shaped lower load sensors 22 are provided on the upper surface of the table base 20 and around the through hole 20a. In this example, three lower load sensors 22 are supported by the table base 20 and are arranged at approximately equal intervals along the circumferential direction of the through hole 20a.

[0034] Each lower load sensor 22 detects a downward load applied to the chuck table 12. However, the number of lower load sensors 22 is not limited to three. The table base 20 only needs to be provided with at least one lower load sensor 22 located near the contact area between the polishing pad 50b and the wafer 11.

[0035] The lower load sensor 22 is, for example, a diaphragm-type load cell, but it may also be a column-type load cell. The load cell includes a sensor that converts the load into an electrical signal. For example, the load cell is equipped with a piezoelectric sensor having a piezoelectric element, but instead, it may be equipped with a strain gauge type sensor or a capacitive type sensor, etc.

[0036] The upper surface of the lower load sensor 22 is in contact with the lower surface of the stator 16b. The force pushing the chuck table 12 downwards is transmitted to the lower load sensor 22 via the stator 16b. Since each lower load sensor 22 is connected to a controller 54 (described later), the controller 54 can acquire the downward load applied to the chuck table 12 in real time.

[0037] In this embodiment, the controller 54 handles the sum of the loads obtained by each lower load sensor 22 during the processing of the wafer 11 with the polishing tool 50 (i.e., load 1, load 2, and load 3 described later) as the load value related to the wafer 11.

[0038] In other words, the load value applied to the wafer 11 (i.e., the first load value or the second load value) means the sum of load 1 measured by the first lower load sensor 22, load 2 measured by the second lower load sensor 22, and load 3 measured by the third lower load sensor 22. Therefore, this load value may be read as the total load value.

[0039] In this embodiment, the polishing apparatus 2 has three lower load sensors 22, so the sum of load 1, load 2, and load 3 is treated as the load value applied to the wafer 11. However, if the polishing apparatus 2 has N lower load sensors 22 (where N is a natural number), the sum of loads 1 through N is treated as the load value applied to the wafer 11.

[0040] By the way, in Figure 3, for the sake of readability, one lower load sensor 22 and the controller 54 are connected by a dashed line, but in reality, all lower load sensors 22 and the controller 54 are connected by wire or wireless.

[0041] The table base 20 is supported by a tilt adjustment mechanism 24. The tilt adjustment mechanism 24 adjusts the tilt of the table base 20 with respect to a plane perpendicular to the Z axis (i.e., the XY plane). The tilt adjustment mechanism 24 includes a fixed support mechanism 24a, a first movable support mechanism 24b, and a second movable support mechanism 24c.

[0042] The fixed support mechanism 24a, the first movable support mechanism 24b, and the second movable support mechanism 24c are each spaced approximately equally along the circumferential direction of the through hole 20a, and the top of each is fixed to the lower surface of the table base 20.

[0043] The fixed support mechanism 24a, the first movable support mechanism 24b, and the second movable support mechanism 24c are positioned so as not to overlap with the lower load sensors 22 in the Z-axis direction. For example, when the table base 20 is viewed from above, the fixed support mechanism 24a, the first movable support mechanism 24b, and the second movable support mechanism 24c, along with the three lower load sensors 22, are located at the vertices of a regular hexagon.

[0044] The fixed support mechanism 24a has a fixed shaft of a predetermined length, and this fixed shaft does not move along the Z-axis. In contrast, the first movable support mechanism 24b and the second movable support mechanism 24c each have a movable shaft with a male screw formed at its upper end.

[0045] The upper end of each movable shaft is rotatably connected to a screw hole in the upper support fixed to the lower surface of the table base 20. A drive source such as a servo motor or pulse motor is connected to the lower end of each movable shaft.

[0046] The movable shaft is rotatable by a drive source. The drive source adjusts the amount the movable shaft is screwed into the upper support, thereby adjusting the tilt of the table base 20 with respect to the XY plane. In accordance with the tilt of the table base 20, the rotor 16a tilts in accordance with the tilt of the table base 20.

[0047] The axis 16a3 of the rotor 16a is tilted by a small angle with respect to the Z-axis. More specifically, it is tilted by a small angle such that the arc-shaped region on the holding surface 12a (the region shown by the arc-shaped dashed line in Figure 4) is approximately parallel to the XY plane.

[0048] The first motor 18 is connected to the first power supply unit 28 via the first ammeter 26. The first ammeter 26 measures the current flowing through the first motor 18 and notifies the controller 54 of the current value. Therefore, the controller 54 can obtain the current value flowing through the first motor 18 in real time.

[0049] The first power supply unit 28 includes a DC power supply (not shown) and a predetermined circuit (not shown) for changing the voltage supplied from the DC power supply to the first motor 18. The predetermined circuit is, for example, a circuit that changes the voltage supplied from the DC power supply to the first motor 18 using a PWM (Pulse Width Modulation) method or a linear method. The rotational speed of the chuck table 12 is controlled by the controller 54 adjusting the voltage supplied to the first motor 18 through the first power supply unit 28.

[0050] A vibration sensor 20b is fixed to the side of the table base 20. The vibration sensor 20b may be a contact type, provided in contact with the object to be measured, or a non-contact type, provided away from the object to be measured and not in contact with it. The vibration sensor 20b in this embodiment is a contact type and includes acceleration sensors, velocity sensors, displacement sensors, etc.

[0051] The controller 54 uses the vibration sensor 20b to acquire the intensity, frequency, and other properties of vibrations caused by the combined vibration of the table base 20, table base 14, chuck table 12, etc.

[0052] A polishing unit 30 is provided above the chuck table 12. The polishing unit 30 is mounted to be movable along the Z-axis by a Z-axis feed mechanism (not shown) including a ball screw and a motor.

[0053] The polishing unit 30 has a bottomed cylindrical holding member 32. The Z-axis axial feed mechanism described above is connected to the holding member 32, and as the holding member 32 moves along the Z axis, the polishing unit 30 moves along the Z axis. A cavity is provided in the radial center of the holding member 32, and a cylindrical spindle housing 34 is provided in this cavity.

[0054] The spindle housing 34 is physically fixed to the bottom plate of the holding member 32. A vibration sensor 34a is fixed to the side of the spindle housing 34. The vibration sensor 34a is substantially the same as the vibration sensor 20b described above.

[0055] The controller 54 uses the vibration sensor 34a to acquire the intensity, frequency, etc., of vibrations caused by the combined vibration of the spindle 38, polishing tool 50, etc., which will be described later. A small gap is provided between the bottom plate and the side plate of the holding member 32. Multiple (three in this embodiment) upper load sensors 36 are provided in this gap.

[0056] The upper surface of each upper load sensor 36 is fixed to the lower surface of the side plate of the holding member 32, and the lower surface of each upper load sensor 36 is fixed to the upper surface of the bottom plate of the holding member 32. In other words, the bottom plate and side plate of the holding member 32 are fixed via multiple upper load sensors 36.

[0057] Each upper load sensor 36 is, for example, a diaphragm-type or column-type load cell. A downward force (i.e., tensile force) along the Z-axis is constantly acting on each upper load sensor 36 due to forces such as the weight of the polishing unit 30.

[0058] However, during polishing, the polishing unit 30, which is moved by the Z-axis feed mechanism, pushes the wafer 11 downward, and as a reaction, the polishing unit 30 receives an upward force.

[0059] At this time, an upward force (i.e., a compressive force) acts on each upper load sensor 36. This compressive force reduces the tensile force acting on the upper load sensors 36. In other words, an upward load acting on the polishing unit 30 is detected in accordance with the decrease in the tensile force acting on the upper load sensors 36.

[0060] Since each upper load sensor 36 is connected to the controller 54, the controller 54 can acquire the upward load applied to the polishing tool 50 in real time. The controller 54 treats the sum of the loads (load 1, load 2, and load 3) obtained by each upper load sensor 36 during the processing of the wafer 11 with the polishing tool 50 as the load value applied to the polishing tool (first processing tool, second processing tool) 50.

[0061] In other words, in this embodiment, the load value applied to the polishing tool 50 (i.e., the first load value or the second load value) means the sum of load 1 measured by the first upper load sensor 36, load 2 measured by the second upper load sensor 36, and load 3 measured by the third upper load sensor 36. Therefore, this load value may be read as the total load value.

[0062] In this embodiment, the polishing device 2 has three upper load sensors 36, so the sum of load 1, load 2, and load 3 is treated as the load value applied to the polishing tool 50. However, if the polishing device 2 has N upper load sensors 36 (where N is a natural number), the sum of loads 1 through N is treated as the load value applied to the polishing tool 50.

[0063] Note that in Figure 3, for the sake of clarity, one upper load sensor 36 and the controller 54 are connected by a dashed line; however, in reality, all upper load sensors 36 and the controller 54 are connected by wire or wireless.

[0064] A portion of a cylindrical spindle 38 is rotatably housed in the spindle housing 34. The longitudinal direction of the spindle 38 is aligned with the Z-axis. A second motor 40, such as a DC (Direct Current) servo motor, is provided inside the spindle housing 34.

[0065] The second motor 40 functions as a spindle motor. The second motor 40 includes a rotor fixed to the spindle 38 and a stator provided around the rotor. The second motor 40 is connected to the second power supply unit 44 via a second ammeter 42. The second ammeter 42 measures the current flowing through the second motor 40 and notifies the controller 54 of the current value.

[0066] Therefore, the controller 54 can acquire the current value flowing to the second motor 40 in real time. The second power supply unit 44 includes a DC power supply (not shown) and a predetermined circuit (not shown) for changing the voltage supplied from this DC power supply to the second motor 40.

[0067] The predetermined circuit is, for example, a circuit that changes the voltage supplied from the DC power supply to the second motor 40 using a PWM method or a linear method. The rotational speed of the spindle 38 is controlled by the controller 54 adjusting the voltage supplied to the second motor 40 through the second power supply unit 44.

[0068] The lower end of the spindle 38 protrudes below the bottom surface of the retaining member 32 through a through-hole 32a provided in the bottom plate of the retaining member 32. A disc-shaped mounter 48 is fixed to the lower end of the spindle 38.

[0069] An annular polishing tool 50 is fixed to the bottom surface of the mount 48 using bolts (not shown). In other words, the polishing tool (machining tool, first polishing tool, second polishing tool) 50 is attached to the lower end of the spindle 38. The polishing tool 50 in this embodiment is a dry polishing wheel used for so-called dry polishing.

[0070] The polishing tool 50 comprises a disc-shaped base member 50a and an annular polishing pad 50b fixed to one surface of the base member 50a. The polishing pad 50b is a polishing layer in which abrasive grains formed of diamond or the like are dispersed in a base material such as hard polyurethane, and the abrasive grains are fixed to the base material with a bonding agent.

[0071] The polishing pad 50b has an opening 50b1 in the center, and the radial width of the polishing pad 50b is approximately the same as the radius of the wafer 11, but is slightly smaller than the radius of the wafer 11, as shown in Figure 4.

[0072] In this embodiment, with the holding surface 12a and the wafer 11 arranged concentrically, the rotation center 12b of the holding surface 12a (see Figure 4) is located at the edge of the opening 50b1 of the polishing pad 50b, and a portion of the wafer 11 is located outside the outer peripheral edge of the polishing pad 50b in the radial direction of the polishing pad 50b.

[0073] Returning to Figure 3, a temperature sensor 52 is provided near the chuck table 12 for non-contact measurement of the temperature of the contact area (also called the processing point) between the polishing pad 50b and the wafer 11. The temperature sensor 52 is either a radiation thermometer or an optical thermometer.

[0074] The temperature sensor 52 is, for example, an infrared sensor, which is a typical example of a radiation thermometer, and calculates the temperature of the contact area in response to the infrared light or heat emitted from the contact area between the polishing pad 50b and the wafer 11.

[0075] The polishing apparatus 2 has a controller 54 that controls the operation of the chuck table 12, tilt adjustment mechanism 24, spindle 38, Z-axis feed mechanism, etc. The controller 54 is composed of a computer having, for example, a processor 54a represented by a CPU (Central Processing Unit) and memory 54b.

[0076] Memory 54b includes a main memory such as DRAM (Dynamic Random Access Memory) and an auxiliary memory such as flash memory. Software containing a predetermined program is stored in the auxiliary memory. The functions of the controller 54 are realized by operating the processor 54a and other components according to this software.

[0077] The predetermined program executed by processor 54a may be stored on a non-temporary tangible recording medium such as a USB (Universal Serial Bus) memory, optical disk, SD memory card, or HDD (Hard Disk Drive) instead of an auxiliary storage device.

[0078] A touch panel display 56 is connected to the controller 54. The touch panel display 56 functions as an input device for the operator to input instructions to the controller 54, and also functions as a display device for showing processing conditions, log data, etc.

[0079] Alternatively, instead of the touch panel display 56, a display device that does not have input functionality may be provided on the polishing device 2. However, in this case, an input device (keyboard, mouse, trackball, touchpad, digitizer, etc.) for the operator to input instructions to the polishing device 2 will be provided separately.

[0080] When dry polishing is performed on the wafer 11, first, the wafer 11, with protective tape 13 attached to the other surface 11b so that one surface (i.e., the surface to be processed) 11a is exposed upwards, is held in place by suction on the holding surface 12a via the protective tape 13.

[0081] Next, while the chuck table 12 and the polishing tool 50 are rotated at predetermined speeds, the polishing unit 30 is pressed against the wafer 11 with predetermined pressure using the Z-axis feed mechanism. At this time, the area of ​​the wafer 11 located at the highest point of the holding surface 12a (the area shown by the arc-shaped dashed line in Figure 4) is polished by the polishing pad 50b.

[0082] In this embodiment, the wafer 11 (i.e., the first workpiece) is polished (i.e., processed) with the polishing tool 50 (i.e., the first polishing tool), and during the polishing (i.e., processing), a first load value applied to the wafer 11 and first processing information relating to the processing of the wafer 11 (i.e., first processing information other than the first load value) are obtained.

[0083] The first load value is obtained by processing the first processing information. Specifically, the controller 54 can obtain the first load value by acquiring the first processing information and then calculating the sum of loads 1 to 3 in the first processing information.

[0084] As described above, the first load value applied to the wafer 11 is the sum of load 1, load 2, and load 3 measured by the three lower load sensors 22, respectively. However, instead of the first load value applied to the wafer 11, the first load value applied to the polishing tool 50 obtained during polishing may be used. As described above, the first load value applied to the polishing tool 50 is the sum of load 1, load 2, and load 3 measured by the three upper load sensors 36, respectively.

[0085] Furthermore, the first processing information includes (1) load 1, (2) load 2, (3) load 3, (4) rotational speed of the spindle 38, (5) current value flowing to the second motor 40 (hereinafter sometimes simply referred to as the spindle current value), (6) relative Z-axis position of the polishing tool 50 with respect to the holding surface 12a (hereinafter sometimes simply referred to as the Z position), (7) temperature of the contact area between the polishing pad 50b and the wafer 11 (hereinafter sometimes simply referred to as temperature), (8) downward movement speed of the polishing unit 30, (9) load torque of the motor constituting the Z-axis feed mechanism, (10) load torque of the first motor 18 that rotates the chuck table 12, and (11) rotational speed of the chuck table 12.

[0086] In this embodiment, the spindle current value is calculated based on the current value flowing to the second motor 40 during air cut (i.e., when the polishing pad 50b is spinning freely above the wafer 11 without contacting the wafer 11), and the relative position of the polishing tool 50 in the Z-axis direction with respect to the holding surface 12a is calculated based on the position where the air cut was initiated.

[0087] Furthermore, the spindle current value does not necessarily have to be based on the current value flowing to the second motor 40 at the air cut start position. It may also be based on the current value flowing to the second motor 40 when the polishing tool 50 is located at a predetermined distance in the Z-axis direction from the upper surface of the wafer 11 (in this example, one surface 11a) and air cut is being performed.

[0088] The first machining information further includes (12) the vibration of the chuck table 12 measured by the vibration sensor 20b, (13) the vibration of the spindle 38 measured by the vibration sensor 34a, (14) the relative position of the chuck table 12 and the polishing tool 50 in a predetermined direction perpendicular to the Z axis (for example, the X axis direction), and (14) the room temperature of the room in which the polishing apparatus 2 is installed.

[0089] Furthermore, although not used in polishing apparatus 2 which performs dry polishing, when wet polishing or other processing (grinding, cutting, etc.) is performed, the first processing information further includes (15) the flow rate of polishing fluid or processing water supplied to each processing point, and the characteristics of the polishing fluid such as the concentration, type, and temperature of the polishing fluid.

[0090] In addition, when the chuck table 12 is moved between the loading / unloading area and the machining area by an X-axis movement mechanism including a ball screw and a motor, the first machining information includes (16) the load torque of the motor of the X-axis movement mechanism.

[0091] Furthermore, if the loading arm provided on the processing device automatically transports the wafer 11 from the cassette to the chuck table 12 without the operator performing the transport, the first processing information other than the first load value includes (17) the load torque of the motor that moves the loading arm. The controller 54 can acquire the information from (1) to (17) at a constant time interval (for example, several ms to tens of ms).

[0092] In this embodiment, the first machining information includes (1) load 1, (2) load 2, (3) load 3, (5) spindle current value, (6) Z position, and (7) temperature (see Figure 5(B)). Of course, the first machining information may include other information as well.

[0093] Next, the method for processing the wafer 11 (and the method for creating the judgment conditions) will be described with reference to Figures 1 and 2, and Figures 5(A) to 14. In this embodiment, first, the judgment conditions are stored in the memory 54b of the polishing apparatus 2 (S10). Storing the judgment conditions in the memory 54b of the polishing apparatus 2 (S10) can be divided into the steps shown in Figure 2.

[0094] Figure 2 is a flowchart showing a method for storing the determination conditions in the memory 54b of the polishing apparatus 2. S10 includes preparing the data acquired when the wafer (i.e., the first workpiece) 11 is processed with the polishing tool (i.e., the first polishing tool) 50 (S12).

[0095] The data acquired at this time includes (1) through (17) above. Preparing the data (S12) means, for example, storing the data previously obtained with the same polishing device 2 in the memory 54b of the polishing device 2 to be used.

[0096] In S12, it is preferable to use previous data obtained using the same polishing device 2. Using previously obtained data from the same polishing device 2 allows for a higher reliability of the judgment compared to using previously obtained data from a different polishing device 2.

[0097] Furthermore, the old data can be automatically replaced with new data each time processing is completed, and judgment conditions can be created using this new data. In addition, data obtained by another polishing device 2 may be supplied to the polishing device 2 that will polish the wafer 11 from now on, via technical means such as wireless communication.

[0098] Of course, data exchange between the two polishing devices is not limited to direct data exchange via wireless communication; data may also be exchanged between the two polishing devices via a PC (Personal Computer), server, etc. After S12, select and retain some of the data to be used when classifying into multiple groups (S14).

[0099] Figure 5(A) is an example of the screen of the touch panel display 56 showing the entirety of the data before selective retention. Note that the dots shown in Figure 5(A) indicate that information is actually present, but for the sake of clarity, that information has been omitted. The same applies to subsequent figures.

[0100] Figure 5(A) shows an overview of the data acquired when the wafer 11 was processed with the polishing tool 50. The data overview shown in Figure 5(A) includes (i) the date and time the data was acquired, (ii) the processing ID (identification) number, (iii) the ID number of the wafer 11, (iv) the chuck table 12 used, and (v) a checkbox to specify whether or not to select it.

[0101] (ii) The processing ID number is a sequential number assigned to all polished wafers 11 in the order in which they were polished. (iii) The wafer 11 ID number is a unique identification number assigned to the wafer 11 before processing.

[0102] (iv) The chuck table 12 used refers to the type of chuck table 12 that was actually used when polishing the wafer 11. (v) A check mark is placed in the check box when the operator touches the box. The check mark can be removed when the operator touches the box again.

[0103] The worker selects and saves the data for wafers 11 that have been polished successfully (i.e., have become good products). Successful polishing means, for example, that, upon visual inspection by the worker, surface burning and chipping (i.e., breakage) are (a) below a predetermined tolerance, (b) almost absent, or (c) completely absent.

[0104] Alternatively, instead of relying on visual inspection by the worker, the surface burn, chipping, and in-plane thickness variations of the wafer 11 may be quantitatively evaluated by taking an image of the polished surface after polishing and applying image processing to the resulting image.

[0105] Incidentally, in order to selectively retain the data of wafers 11 that have achieved good polishing results, if good processing results are obtained in the most recent polishing, the data of wafers 11 that have achieved good processing results may be selectively retained in the polishing apparatus 2 in advance. This eliminates the need for the operator to make selections in S14.

[0106] Alternatively, instead of selecting the data of wafer 11 for which the polishing results were good, the operator may also select the data of wafer 11 (i.e., first workpiece) 11 that has specifications that are not exactly the same as, but close to, the specifications of the wafer to be polished (i.e., second workpiece) 11.

[0107] The specifications of wafer 11 include, for example, the thickness, size (e.g., diameter), material, shape, and structure (e.g., whether it is a single wafer or a stacked wafer).

[0108] By the way, in addition to selectively retaining data for wafers 11 that have been polished successfully, the condition of the wafer 11 before polishing (for example, whether or not there are edge chips) can also be recorded as history. If there is an abnormality in the wafer 11 before polishing (for example, edge chips), a check mark may not be placed, or a check mark that has been placed may be canceled. If the condition of the wafer 11 before processing is poor (for example, there are edge chips), there is a high possibility that an abnormality will occur in subsequent processing, so it is preferable to exclude it in advance.

[0109] In the example shown in Figure 5(A), the operator selects two data points, processing ID numbers 1 and 50, from the most recently acquired data (see the "Use as a criterion or not" column). After making the selection, the operator touches the "Save Selection" button, and processing ID numbers 1 and 50 are selected and remain as data points used for classification into multiple groups.

[0110] Alternatively, instead of checking the boxes next to the data you want to keep, you can selectively exclude data by checking the boxes next to the data you want to exclude.

[0111] Figure 5(B) shows an example of the screen of the touch panel display 56 displaying the data included in processing ID number 1. The data included in processing ID number 1 includes elapsed time (s), load value (i.e., the sum of load 1, load 2, and load 3) (N), load 1 (N), load 2 (N), load 3 (N), spindle current value (A), Z position (μm), and temperature (°C). Processing ID number 50 also includes similar data.

[0112] Figure 6 shows an example of the touch panel display 56 screen displaying all of the selectively retained data. When the "Select and Save" button is pressed with processing ID numbers 1 and 50 selected, the range of processing ID numbers 1 and 50 is highlighted.

[0113] After S14, the controller 54 classifies the data for machining ID numbers 1 and 50 into multiple groups according to the load value (S16). A predetermined program (first program) for performing the classification is stored in memory 54b (particularly in auxiliary storage), and the classification is performed when the processor 54a reads and executes the first program.

[0114] Figure 7(A) is an example of the screen of the touch panel display 56 showing an example of data classified into group 1. The data included in group 1 is data where the load value is between 0 (N) and 1 (N), and includes processing ID number 1, elapsed time (s), load 1 (N), load 2 (N), load 3 (N), spindle current value (A), Z position (μm), and temperature (°C).

[0115] Figure 7(B) shows an example of the screen of the touch panel display 56, illustrating an example of data classified as Group 2. The data included in Group 2 consists of load values ​​greater than 1(N) and less than or equal to 2(N), and contains the same type of information as Group 1.

[0116] Figure 7(C) shows an example of the screen of the touch panel display 56, illustrating an example of data classified into group 300. The data included in group 3 consists of load values ​​greater than 299(N) and less than or equal to 300(N), and contains the same type of information as group 1.

[0117] By the way, the closed and open intervals for the load values ​​in each group described above are just examples. The load values ​​for Group 1 could be set to 0(N) or more and less than 1(N), the load values ​​for Group 2 could be set to 1(N) or more and less than 2(N), and similarly, the load values ​​for Group 300 could be set to 299(N) or more and less than 300(N).

[0118] In this embodiment, data including load values ​​(i.e., first load values) and processing information (first processing information) obtained when the wafer (first workpiece) 11 is processed is classified into multiple groups according to the load value (i.e., first load value).

[0119] After S16, the controller 54 creates a determination condition for each group based on the data classified into multiple groups (S18). A predetermined program (second program) for creating the determination condition is stored in memory 54b (particularly in auxiliary storage), and the creation is performed when the processor 54a reads and executes the second program.

[0120] In this embodiment, since the distribution of numerical values ​​for each item, such as Load 1, Load 2, etc., in the data for each group is approximately a normal distribution, a judgment condition is created in which the range of 3σ (i.e., the range of mean μ ± (3 × standard deviation σ)) among the numerical values ​​of each item is considered to be within the normal range.

[0121] Note that instead of 3σ, the minimum value X MIN From the maximum value X MAX The range up to (minimum value X) can be considered the normal range, MIN -α) from (maximum value X MAX The normal range may be defined as a range up to +α) (where α is a predetermined value), or a range obtained by machine learning on a computer may also be defined as the normal range.

[0122] The judgment conditions created for each group according to the load value are stored in a separate area of ​​memory 54b from the data as judgment conditions for diagnosing the state during processing. For example, the judgment conditions are stored in a specially labeled judgment condition folder in memory 54b.

[0123] Figure 8 shows an example of the screen of a touch panel display 56, illustrating an example of the judgment criteria for Group 1 among several groups. The numerical ranges for each item are filtered within a 3σ range. The numerical ranges shown for Load 1 (N), Load 2 (N), etc., indicate the upper and lower limits of the 3σ range, which is considered to indicate a good condition during processing.

[0124] Of course, the criteria for determining all groups are stored in memory 54b, such as Group 2 for loads greater than 1(N) and 2(N) or less, Group 3 for loads greater than 2(N) and 3(N) or less, and so on.

[0125] The judgment criteria created in this manner are formed by selectively using data from wafer 11, which showed good polishing results, and can therefore be considered to represent the normal range within the first processing information in which normal polishing (i.e., processing) can be performed.

[0126] After the completion of S10, the polishing tool (i.e., the second processing tool) 50 mounted on the spindle 38 of the polishing apparatus 2, which has the judgment conditions stored in it, polishes (i.e., processes) one surface 11a of the wafer (i.e., the second workpiece) 11, and the controller 54 acquires the second load value and the second processing information, and diagnoses the state of the wafer (i.e., the second workpiece) 11 during processing by the processing tool (i.e., the second processing tool) 50 (S20).

[0127] Furthermore, since the second load value is obtained by processing the second processing information, the controller 54 can obtain the second load value by calculating the sum of loads 1 to 3 in the second processing information after acquiring the second processing information.

[0128] In this embodiment, the polishing tool 50 used when polishing one surface 11a of the wafer 11 to obtain the determination conditions (i.e., the first processing tool) 50 and the polishing tool 50 used when polishing one surface 11a of the wafer 11 and diagnosing the processing condition using the determination conditions (i.e., the second processing tool) 50 are the same (i.e., the type of abrasive grain, the grit size of the abrasive grain, the bonding material, the diameter of the polishing pad 50b, the hardness of the polishing pad 50b, etc. are the same).

[0129] Normally, polishing tools 50 of the same material and diameter are used to make the most effective use of the judgment criteria. For example, the polishing tool used to polish one surface 11a of the wafer 11 in order to obtain the judgment criteria is also used when diagnosing the condition during processing.

[0130] However, the polishing tool 50 used to obtain the judgment conditions and the polishing tool 50 used to diagnose the state during processing using the judgment conditions may be different. For example, an old and a new polishing tool 50 of the same material and diameter can be used.

[0131] In this embodiment, the wafer polished when obtaining the determination conditions (i.e., the first workpiece) 11 and the wafer polished when diagnosing the processing state using the determination conditions (i.e., the second workpiece) 11 are usually different wafers 11.

[0132] Generally, wafer 11 (i.e., the first workpiece) and wafer 11 (i.e., the second workpiece) are identical in thickness, size, shape, and material, but have different ID numbers; in other words, they are different wafers 11.

[0133] However, the wafer (i.e., the second workpiece) 11 may be another wafer 11 that is similar to the wafer (i.e., the first workpiece) 11. A similar wafer 11 means that at least two or three of the following are the same: thickness, size, shape, and material.

[0134] During the polishing (i.e., processing) of the wafer (i.e., the second workpiece) 11 with the polishing tool (i.e., the second processing tool) 50, a second load value applied to the wafer 11 and second processing information related to the processing of the wafer 11 (i.e., second processing information other than the second load value) are acquired simultaneously.

[0135] In this embodiment, the first load value applied to the wafer 11 is used as the first load value, and similarly, the second load value applied to the wafer 11 is used as the second load value. However, if the first load value applied to the polishing tool 50 is used as the first load value, then similarly, the second load value applied to the polishing tool 50 may be used as the second load value.

[0136] However, since the load value applied to the wafer 11 and the load value applied to the polishing tool 50 are in an action-reaction relationship, the first load value applied to the wafer 11 may be used as the first load value, and the second load value applied to the polishing tool 50 may be used as the second load value. Conversely, the first load value applied to the polishing tool 50 may be used as the first load value, and the second load value applied to the wafer 11 may be used as the second load value.

[0137] Incidentally, the second processing information includes, for example, only the load 1 (N), load 2 (N), load 3 (N), spindle current value (A), Z position (μm), and temperature (°C) that are included in the judgment conditions, respectively.

[0138] In this case, the load on the processor 54a can be reduced compared to the case where the second processing information includes all of (1) to (17) above. However, if the load on the processor 54a is not a problem, the second processing information may include all of (1) to (17) above.

[0139] As the acquisition of the second load value and the second processing information progresses, the controller 54 diagnoses the state of the wafer (i.e., the second workpiece) 11 during processing with the processing tool (i.e., the second processing tool) 50, according to the determination conditions for the first load value corresponding to the second load value.

[0140] The judgment condition for the first load value corresponding to the second load value means the judgment condition for the same first load value as the second load value. For example, if the second load value is between 0(N) and 1(N), the controller 54 diagnoses the state of the wafer 11 during processing according to the judgment condition for group 1, where the first load value is between 0(N) and 1(N).

[0141] Figure 9 shows an example of the acquired second processing information. In the example shown in Figure 9, load 1 is 0.8 (N), load 2 is 0.05 (N), and load 3 is 0.1 (N), so the first load value is 0.095 (N).

[0142] In this case, the controller 54 refers to the determination conditions for group 1 (see Figure 8) and determines whether each of the load 1, load 2, load 3, spindle current value, Z position, and temperature shown in Figure 9 falls within the numerical range shown in Figure 8.

[0143] In the example shown in Figure 9, load 1 is between 0.3(N) and 0.8(N), loads 2 and 3 are both between 0.0(N) and 0.1(N), the Z position is between 8(μm) and 20(μm), and the temperature is between 20(°C) and 30(°C). However, the spindle current value exceeds 0.09(A), so the controller 54 diagnoses that the machining conditions are not good.

[0144] In response, the controller 54 determines that the machining conditions are good if the load 1 (N), load 2 (N), load 3 (N), spindle current value (A), Z position (μm), and temperature (°C) are all within the range shown in Figure 8 for the corresponding items.

[0145] Figure 10 is a flowchart showing a method for diagnosing the state of wafer 11 during processing. In the flowchart shown in Figure 10, the load value recorded as a judgment condition is clearly indicated as the first load value, and the load value acquired during processing is clearly indicated as the second load value to distinguish them.

[0146] When diagnosing the processing condition of the wafer 11, the polishing tool 50 polishes one surface 11a of the wafer 11, and the controller 54 acquires the current second load value and second processing information at a fixed time interval (for example, several ms to tens of ms) (S21).

[0147] The controller 54 then identifies a group of first load values ​​that corresponds to the current second load value in the determination conditions (S22). Next, the controller 54 determines whether the current second machining information satisfies the determination conditions of the corresponding group (i.e., whether the machining conditions are good or not).

[0148] In other words, the controller 54 diagnoses the state of the wafer 11 during polishing with the polishing tool 50 according to the corresponding determination conditions. In this embodiment, if the second processing information is within the numerical range of the determination conditions, it is diagnosed that the state during polishing is good, and if it is outside the numerical range of the determination conditions, it is diagnosed that the state during polishing is not good.

[0149] Furthermore, the diagnosis of the polishing condition is not limited to a binary diagnosis of good or bad. In addition to whether or not it falls within the numerical range specified in the judgment conditions, the degree to which it deviates from the numerical range specified in the judgment conditions may be indicated in steps or continuously using an index.

[0150] If the diagnostic result is favorable (YES in S23), the controller 54 waits for a predetermined time (e.g., 1 s) without acquiring a new second load value and second processing information (S24), and then returns to S21. However, if YES is obtained in S23, the predetermined waiting time (S24) may be omitted and the system may return to S21.

[0151] In contrast, if the diagnostic result is not favorable (NO in S23), the controller 54 increments a predetermined variable (S25). Note that incrementing a predetermined variable can be interpreted as increasing the count of some numerical value by a predetermined number.

[0152] After incrementing a predetermined variable (S25), the controller 54 determines whether the predetermined variable is equal to or greater than a threshold. If the predetermined variable is less than the threshold (NO in S26), the controller waits for a predetermined time (S24). If NO is obtained in S26, the controller may skip the predetermined waiting time (S24) and return to S21.

[0153] In response to this, if a predetermined variable exceeds a threshold (YES in S26), the controller 54 indicates that an abnormality has occurred in the processing and notifies the operator of the abnormality through sound, light, images, etc. via a speaker, LED (Light Emitting Diode) lamp, touch panel display 56, etc. (S27).

[0154] If an abnormality is reported, the polishing device 2 will suspend processing, the wafer 11 will be removed from the chuck table 12, and the polishing device 2 will be inspected by the operator.

[0155] Furthermore, after the controller 54 notifies the operator of an abnormality in S27, the operator may interrupt the machining process, perform recovery work such as dressing the polishing pad 50b, and then resume machining. Alternatively, after notifying the operator of an abnormality, the operator may continue machining without interrupting the process, simply logging the occurrence of the abnormality.

[0156] Incidentally, in S21, moving averages of the second load value and the second machining information may be obtained over a time span of 1 (s) to several (s). By making the determination in S23 based on this moving average, the influence of instantaneous abnormalities occurring in load 1, load 2, load 3, spindle current value, Z position, temperature, etc., can be reduced, and the occurrence of a machining abnormality can be detected.

[0157] In this embodiment, by using judgment conditions set individually according to the load value, it is possible to detect whether or not a machining abnormality has occurred more appropriately than when detecting a machining abnormality based solely on whether or not the spindle current value exceeds a threshold.

[0158] In addition, by monitoring the actual contact between the polishing tool 50 and the wafer 11 through the load value, and by cumulatively determining whether the judgment conditions, which are defined in stages according to the load value, are met using predetermined variables, it is possible to provide a highly reliable diagnosis that is not affected by temporary abnormalities.

[0159] Next, referring to Figures 11 to 14, the reason for adopting load values ​​to create the judgment conditions in this embodiment will be explained. The inventors of the present application investigated the causes of processing defects such as surface burning and chipping that occur as a result of polishing (i.e., processing) in the polishing apparatus 2 described above.

[0160] While various causes of machining defects are possible, we created judgment conditions according to the machining time (e.g., initial, middle, and late stages). However, we could not find a good correlation between the satisfaction of the judgment conditions and the quality of the machining results. Furthermore, we could not find a good correlation even when creating judgment conditions according to various parameters such as spindle current values.

[0161] Therefore, based on the assumption that a higher correlation could be found between the satisfaction of the judgment conditions and the quality of the processing results by basing the judgment conditions on the degree of direct contact between the wafer 11 and the polishing pad 50b, the judgment conditions were created according to the load value, which is the sum of load 1 to load 3, as described above.

[0162] Figure 11 is a scatter plot showing the quality of surface burning using load value (horizontal axis) and load 3 (vertical axis). In Figure 11, data where surface burning occurred (i.e., the processing conditions were poor) are indicated by light "x" marks, and data where surface burning did not occur (i.e., the processing conditions were good) are indicated by dark circles.

[0163] As shown in Figure 11, when the quality of surface burning is visualized using load value (horizontal axis) and load 3 (vertical axis), it can be seen that although there is some overlap in the data for poor and good processing conditions, they are reasonably separated according to the load value. In other words, Figure 11 indicates that there is relatively high technical significance in creating judgment conditions according to the load value.

[0164] Furthermore, as shown in Figure 11, even at relatively low load values ​​(i.e., in the early stages of processing), a tendency for defects (×) and good products (〇) to be separated can be observed. In other words, this suggests that abnormalities can be detected as early as the start of processing.

[0165] Incidentally, as shown in Figure 11, when the load value is relatively large, the degree of separation between good and bad processing is greater than when the load value is relatively small. Therefore, when diagnosing the processing condition of the wafer (i.e., the second workpiece) 11 (S20), a range of load values ​​in which the defect to be detected (surface burning in the example of Figure 11) is easily detected may be selectively used.

[0166] Figure 12 is a scatter plot showing the quality of surface burning using load value (horizontal axis) and spindle current value (vertical axis). In Figure 12, data where surface burning occurred (i.e., the machining conditions were poor) are indicated by light "x" marks, and data where surface burning did not occur (i.e., the machining conditions were good) are indicated by dark circles.

[0167] Furthermore, when diagnosing the state of wafer 11 during processing (S20), a range of load values ​​that is easily detected (surface burning in the example of Figure 12) may be selectively used. Incidentally, when the horizontal axis is time, the spindle current value tends to increase as the polishing of wafer 11 approaches its end, and defective and good data are mixed together and not separated as much as shown in Figure 12.

[0168] Figure 13 is a scatter plot showing load values ​​(horizontal axis) and load 3 (vertical axis) according to the presence or absence of edge chipping. In Figure 13, data obtained by polishing wafer 11 with polishing apparatus 2 when chipping (i.e., chipping) occurred on the edge of wafer 11 (i.e., the condition before processing was poor) is shown with a light "x", and data obtained by similar polishing when chipping did not occur on the edge (i.e., the condition before processing was good) is shown with a dark circle.

[0169] If there is an edge chip in the wafer 11 before processing (i.e., an abnormality), there is a possibility of defects such as surface burning, or the polishing pad 50b may be gouged out, requiring dressing. As shown in Figure 13, it can be seen that the load 3 relative to the load value serves as an indicator for detecting whether or not there is an abnormality in the wafer 11 before processing.

[0170] Figure 14 is a scatter plot showing load values ​​(horizontal axis) and spindle current values ​​(vertical axis) according to the presence or absence of edge chipping. In Figure 14, data obtained by polishing wafer 11 with polishing apparatus 2 when chipping occurred on the edge of wafer 11 (i.e., the condition before processing was poor) is shown with a light "x", and data obtained by similar polishing when chipping did not occur on the edge (i.e., the condition before processing was good) is shown with a dark circle.

[0171] As can be seen in the example shown in Figure 14, the spindle current value relative to the load value serves as an indicator for detecting the presence or absence of abnormalities in the wafer 11 before processing. Incidentally, the structure, method, etc., according to the above embodiment can be modified as appropriate without departing from the scope of the object of the present invention.

[0172] In the above-described embodiment, an example of a dry polishing apparatus 2 was explained as the processing apparatus. However, the processing apparatus may also be a wet polishing apparatus, grinding apparatus, cutting apparatus (i.e., surface planer), cutting apparatus, water jet saw, etc.

[0173] The wet polishing apparatus is the same as the dry polishing apparatus 2 described above, except that a polishing liquid containing free abrasive particles or a polishing liquid without free abrasive particles is supplied to the contact area between the polishing pad 50b and the workpiece.

[0174] The grinding device basically has the same configuration as the polishing device 2, but differs in that a grinding wheel (i.e., a machining tool) is mounted on the spindle 38 via a mounter 48, and a polishing fluid such as pure water is supplied to the contact area between the grinding wheel and the workpiece.

[0175] The cutting machine basically has the same configuration as the grinding machine 2, but differs in that a cutting wheel with a diamond cutting tool (i.e., a machining tool) is mounted on the spindle 38 via a mounter 48.

[0176] The cutting device is positioned along a predetermined direction (for example, the Y-axis direction) where the longitudinal direction of the spindle is perpendicular to the Z-axis, and an annular cutting blade (i.e., a machining tool) is mounted on the tip of the spindle.

[0177] In cutting machines, measuring the load on the cutting blade is difficult, so the load on the workpiece is measured by a load sensor via the chuck table of the cutting machine. Unlike the chuck table 12 described above, the chuck table of the cutting machine has a frame and a porous plate with a substantially flat upper surface, and is positioned substantially parallel to the XY plane perpendicular to the Z axis.

[0178] A water jet saw does not have a spindle. It has a nozzle that opens downwards and a jig (i.e., a holding table) for holding the workpiece. A through-hole can be formed in the workpiece held by the jig by discharging a liquid mixture of pure water and abrasive particles downwards along the Z-axis from the nozzle opening.

[0179] Furthermore, by moving the nozzle and the jig holding the workpiece relatively along the XY plane perpendicular to the Z axis, the workpiece can be cut along this movement path. In a water jet saw, a load sensor is provided on the bottom surface of the jig, and the load applied to the workpiece is measured by the load sensor via the jig. [Explanation of symbols]

[0180] 2: Polishing equipment (processing equipment) 11: Wafer (workpiece, first workpiece, second workpiece) 11a: One side, 11b: The other side, 13: Protective tape 12: Chuck table (holding table), 12a: Holding surface, 12b: Center of rotation 14: Table base 16: Air bearing 16a: Rotor, 16a1: Large diameter part, 16a2: Small diameter part, 16a3: Axis center 16b: Stator 18: First motor 20: Table base, 20a: Through hole, 20b: Vibration sensor 22: Lower load sensor 24: Tilt adjustment mechanism 24a: Fixed support mechanism, 24b: First movable support mechanism, 24c: Second movable support mechanism 26: First ammeter, 28: First power supply unit 30: Polishing Unit 32: retaining member, 32a: through opening 34: Spindle housing, 34a: Vibration sensor 36: Upper load sensor 38: Spindle 40: Second motor, 42: Second ammeter, 44: Second power supply unit 48: Mounter 50: Grinding tools (grinding tool, first grinding tool, second grinding tool) 50a: Base member, 50b: Polishing pad, 50b1: Opening 52: Temperature sensor 54: Controller, 54a: Processor, 54b: Memory 56: Touch panel display

Claims

1. A machining method in which a workpiece is machined with a machining tool, In a machining apparatus in which determination conditions for diagnosing the state during machining are stored in memory, based on a first load value obtained during machining of a first workpiece with a first machining tool, applied to the first workpiece or the first machining tool, and first machining information other than the first load value related to the machining of the first workpiece, the apparatus performs machining of a second workpiece with a second machining tool, During the machining of the second workpiece with the second machining tool, a second load value applied to the second workpiece or the second machining tool, and second machining information other than the second load value related to the machining of the second workpiece are acquired. The process involves diagnosing the state of the second workpiece during machining with the second machining tool, in accordance with the determination conditions for the first load value corresponding to the second load value. A processing method characterized by comprising the following:

2. Storing the determination condition in the memory means The data, including the first load value and the first processing information obtained when the first workpiece is processed, is classified into multiple groups according to the first load value. The processing method according to claim 1, characterized in that it includes creating a determination condition for each group based on the data classified into the plurality of groups.

3. Storing the determination conditions in the memory of the processing device is, The processing method according to claim 2, characterized in that, before classifying the data into the multiple groups, a portion of the data to be used when classifying it into the multiple groups is selected and kept.

4. The first machining tool and the second machining tool each have an abrasive pad, The determination condition is obtained when polishing one surface of the first workpiece with the first processing tool. The machining method according to any one of claims 1 to 3, characterized in that, when diagnosing the state of the second workpiece during machining, one surface of the second workpiece is polished with the second machining tool, and the state of the second workpiece during polishing with the second machining tool is diagnosed according to the determination conditions.

5. A method for creating judgment conditions, The data, which includes the load value applied to the workpiece or the machining tool, and machining information other than the load value related to the machining of the workpiece, obtained during machining of the workpiece with the machining tool, is classified into multiple groups according to the magnitude of the load value. Based on the data classified into these multiple groups, a determination condition is created for each group to diagnose the state of the workpiece during processing. A method for creating a judgment condition that includes the following.

6. A processing device for processing a workpiece, A holding table for holding the workpiece, The spindle on which the machining tool is mounted, A controller having a processor and memory, which controls the operation of the holding table and the spindle, Equipped with, The memory stores determination conditions for diagnosing the state during machining, which are created by classifying the first machining information according to the first load value, based on the first load value obtained during machining of the first workpiece with the first machining tool, the first load value applied to the first workpiece or the first machining tool, and the first machining information other than the first load value related to the machining of the first workpiece. The controller is characterized in that, while the second workpiece is being processed by the second processing tool mounted on the spindle, it acquires a second load value applied to the second workpiece or the second processing tool, and second processing information other than the second load value relating to the processing of the second workpiece, and diagnoses the state of the processing of the second workpiece by the second processing tool according to the determination conditions for the first load value corresponding to the second load value.

Images