Blade tip state inspection method and wafer for inspection

Abstract

To provide a blade tip state inspection method which dissolves a problem that time for work for removing a resist film is required and has been troublesome, when a substrate constituting a wafer for inspection used in a blade tip state inspection method is recycled.SOLUTION: A blade tip state inspection method includes: a step of preparing a wafer for inspection of coating an upper face of a substrate with a water-soluble resin and forming the water-soluble resin, and preparing a wafer for inspection so that its surface is constituted by overlapping a resist film with the water-soluble resin film and coating the resist film; a holding step of holding a rear face of the wafer for inspection on the holding means; a turning mark formation step of rotating a cutting tool of cutting means, turning the surface of the wafer for inspection held by the holding means, and forming a turning mark on the resist film; and an inspection step of inspecting a blade tip state of the cutting tool from the turning mark.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a cutting edge condition inspection method for inspecting the cutting edge condition of a cutting tool, and to an inspection wafer. [Background technology]

[0002] A wafer has a plurality of devices such as ICs and LSIs formed on its surface along dividing lines, and the back surface is ground to the desired thickness. The wafer is then divided into individual device chips using a dicing machine and laser processing machine. These are then used in electrical equipment such as personal computers and mobile phones.

[0003] In addition, the applicant has proposed a processing device that rotates a cutting tool so as to cut the surface of the wafer parallel to the surface of the wafer in order to align the height of the heads of the bumps when multiple protruding electrodes called bumps are arranged on a device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-047651 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the cutting edge of the bit is chipped or worn, the turning cannot be performed properly.

[0006] Therefore, in order to inspect the condition of the cutting edge of a bit used in the processing equipment, a test wafer is prepared by coating the upper surface of a silicon substrate with a resist film, and the test wafer is held with the resist film side facing up on a chuck table that constitutes the processing equipment. The bit is then rotated to cut away the resist film, and the condition of the cutting marks formed in the resist film is checked to inspect the cutting edge condition of the bit.

[0007] As described above, the test wafer used for testing the cutting edge condition of the bit has a surface resist film turned over to form turning marks, and in order to reuse the silicon substrate constituting the test wafer, the test wafer is subjected to a considerable amount of time to remove the resist film using acetone. However, when using acetone to remove the resist film, care must be taken to prevent the acetone from harming the worker during the resist film removal work, and there is a problem that removing the resist film takes time and is troublesome.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and its main technical object is to provide a cutting edge condition inspection method and an inspection wafer which solve the problems that, in a cutting edge condition inspection method for inspecting the cutting edge condition of a bit of a processing device, when reusing a substrate constituting an inspection wafer used in the cutting edge condition inspection method, the operation of removing the resist film takes time and care must be taken not to be harmed by acetone, which is unbearable in terms of the hassle. [Means for solving the problem]

[0009] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a cutting edge condition inspection method for inspecting the cutting edge condition of a cutting edge of a cutting edge in a processing device comprising: a holding means for holding a plate-like object; and a cutting edge means equipped with a rotatable cutting edge that turns the upper surface of the plate-like object held by the holding means in parallel, the cutting edge condition inspection method comprising: an inspection wafer preparation step of preparing an inspection wafer having a surface formed by coating the upper surface of a substrate with a water-soluble resin to form a water-soluble resin film and coating a resist film on top of the water-soluble resin film; a holding step of holding the back surface of the inspection wafer in the holding means; a turning mark formation step of rotating the cutting edge of the cutting edge means to turn the upper surface of the inspection wafer held by the holding means to form turning marks in the resist film; and an inspection step of inspecting the cutting edge condition of the cutting edge from the turning marks.

[0010] It is preferable to include a resist film peeling step in which water is supplied to the inspection wafer after the inspection step, and the water-soluble resin film is dissolved from the substrate to peel off the resist film. It is also preferable that ultrasonic waves are applied via water in the resist film peeling step. Furthermore, after the water-soluble resin film is dissolved and the resist film is peeled off from the substrate, the substrate may be reused.

[0011] According to the present invention, there is provided an inspection wafer having a surface constructed by coating a water-soluble resin on the upper surface of a substrate to form a water-soluble resin film, and then coating a resist film on top of the water-soluble resin film.

[0012] It is preferable that the substrate is a silicon substrate, the water-soluble resin film has a thickness of 2 to 5 μm, and the resist film has a thickness of 30 to 40 μm. Effect of the Invention

[0013] The cutting edge condition inspection method of the present invention is a cutting edge condition inspection method for inspecting the cutting edge condition of a cutting edge of a cutting edge in a processing device including a holding means for holding a plate-like object, and a cutting edge means equipped with a rotatable cutting edge for turning the top surface of the plate-like object held by the holding means, and includes an inspection wafer preparation step of preparing an inspection wafer having a surface configured by coating a water-soluble resin on the top surface of a substrate to form a water-soluble resin film and coating a resist film on top of the water-soluble resin film, a holding step of holding the back surface of the inspection wafer in the holding means, and a cutting edge condition inspection method for inspecting the cutting edge condition of a cutting edge in a processing device including a holding means and a cutting edge condition inspection method, the cutting edge condition inspection method comprising: and an inspection step of inspecting the condition of the cutting edge of the bit from the turning marks. Therefore, in a processing apparatus including a bit means having a rotatable bit that turns the top surface of a plate-like object held by a holding means in a parallel manner, the condition of the cutting edge of the bit, such as whether the tip of the cutting edge of the bit is chipped or worn, can be inspected, and the water-soluble resin film can be dissolved with water to easily remove the resist film, eliminating the problem that the resist film must be removed using acetone, which requires consideration for the safety of the worker, and is therefore unbearable in terms of time.

[0014] In addition, the inspection wafer of the present invention has a surface constructed by coating the upper surface of a substrate with a water-soluble resin to form a water-soluble resin film, and then coating a resist film on top of the water-soluble resin film. Therefore, in a processing apparatus comprising a bit means having a rotatable bit that cuts the upper surface of a plate-like object held by a holding means in a parallel manner, it is possible to inspect the condition of the bit cutting edge, such as whether the tip of the cutting edge of the bit is chipped or worn, and the water-soluble resin film can be dissolved with water to easily remove the resist film, eliminating the problem of the hassle of having to spend a considerable amount of time removing the resist film using acetone, which requires consideration for the safety of the worker. [Brief description of the drawings]

[0015] [Figure 1] FIG. [Diagram 2] FIG. 2(a) is a front view of a cutting tool attached to the processing device of FIG. 1, and FIG. 2(b) is a side view of the cutting tool shown in FIG. [Diagram 3] 11 is a perspective view showing a manner in which a substrate is held on a spinner table in a wafer preparation step for inspection. FIG. [Figure 4] FIG. 11 is a perspective view showing an aspect of forming a water-soluble resin film on a substrate in a test wafer preparation step. [Diagram 5] FIG. 11 is a perspective view showing an aspect in which a resist film is formed on a water-soluble resin film in a step of preparing a wafer for inspection. [Figure 6] FIG. 2A is a perspective view of a test wafer formed by a test wafer preparation step, and FIG. 2B is an enlarged cross-sectional view of a portion of the test wafer shown in FIG. [Figure 7] FIG. 13 is a perspective view showing an embodiment of a holding step. [Figure 8] FIG. 2A is a perspective view showing an embodiment of a turning mark forming step, and FIG. 2B is a perspective view of a test wafer on which turning marks are formed by the turning mark forming step. [Figure 9] FIG. 2A is a perspective view showing an embodiment of a resist film stripping step, and FIG. 2B is a perspective view of a substrate regenerated by the resist film stripping step shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cutting edge state inspection method configured based on the present invention and an inspection wafer suitable for the cutting edge state inspection method will be described in detail with reference to the accompanying drawings.

[0017] FIG. 1 shows an overall oblique view of a processing apparatus 1 including a holding means 5 for holding a plate-like object (wafer W) and a cutting tool means 3 equipped with a rotatable cutting tool 31 for cutting the top surface of the plate-like object held by the holding means 5 in parallel. A cutting edge condition inspection method constructed based on the present invention, which will be described later, is carried out in this processing apparatus 1.

[0018] The processing apparatus 1 includes a substantially rectangular parallelepiped housing 2, which includes a cutting tool 3 for cutting a plate-like wafer W that is a workpiece, a holding means 5 including a chuck table 52 for holding the wafer W, a first cassette 6 arranged on the front side in the drawing for accommodating the wafer W before cutting, a second cassette 7 arranged on the other side in the X-axis direction in the drawing with respect to the first cassette 6 and accommodating the wafer W after cutting, an alignment means 8 arranged adjacent to the first cassette 6 in the Y-axis direction in the drawing for aligning the wafer W, and a wafer holder 5 arranged adjacent to the second cassette 7 in the Y-axis direction. The apparatus includes a cleaning means 9, a first transport means 10 for transporting the wafer W stored in the first cassette 6 to the alignment means 8 and transporting the wafer W that has been subjected to turning and cleaned and dried by the cleaning means 9 to the second cassette 7, a second transport means 11 for transporting the wafer W placed on the alignment means 8 and centered onto the chuck table 52 of the holding means 5 positioned in the carry-in / out area (front side in the figure), a third transport means 12 for transporting the wafer W after turning from the chuck table 52 positioned in the carry-in / out area to the cleaning means 9, and a control means (not shown). Furthermore, an operation panel 14 is provided on the front side of the apparatus housing 2 where the first transport means 10 is disposed, for instructing the control means (not shown) to start and stop turning and for specifying turning conditions, and a display means (not shown) for displaying processing information and the like is also connected to the control means.

[0019] The wafer W to be lathe-machined by the illustrated processing apparatus 1 is, for example, a wafer having a diameter of 300 mm and a thickness of 700 μm. As can be seen from the enlarged view shown in the lower right, the wafer W is a wafer on which a plurality of devices D are partitioned by planned division lines L and formed on the surface Wa, and as shown in a further enlarged view of some of the devices D, a plurality of protruding electrodes (bumps) B (eight in the illustrated example) are formed on the surface of the devices D. The cutting tool means 3 of the processing apparatus 1, which will be described below, rotates a cutting tool 31 so as to be parallel to the surface Wa of the wafer W to lathe the surface Wa, thereby aligning the height of the heads of the bumps B.

[0020] The tool bit means 3 is mounted on the inner surface of the support wall 21 erected on the rear end side of the device housing 2 so as to be movable in the vertical direction along a pair of guide rails 22, 22 extending in the vertical direction. The tool bit means 3 includes a unit housing 33, a turning wheel 32 disposed on the lower end of a rotating shaft 34 rotatably supported on the unit housing 33, a tool bit 31 mounted on the turning wheel 32 and fixed by a screw 32a from the side of the turning wheel 32, an electric motor 35 mounted on the upper end of the unit housing 33 for rotating the turning wheel 32, and a movable base 37 supporting the unit housing 33 via a support member 36. The movable base 37 is provided with a guided groove that slidably fits onto the above-mentioned guide rails 22, 22, and supports the tool bit means 3 so as to be movable in the vertical direction.

[0021] FIG. 2 shows the tool bit 31 removed from the turning wheel 32. FIG. 2(a) is a front view of the tool bit 31, and FIG. 2(b) is a side view. As shown in the figure, the tool bit 31 includes a tool bit cutting edge 31a and a tool bit body 31b in the shape of a rectangular column that holds the tool bit cutting edge 31a. The cutting edge tip 31d of the tool bit cutting edge 31a is made of, for example, a single crystal synthetic diamond. The tool bit cutting edge 31a is fixed to the tool bit body 31b by a screw 31c, and the tool bit cutting edge 31a can be replaced by loosening the screw 31c. When replacing the entire tool bit 31, the tool bit 31 is removed from the turning wheel 32 by loosening the screw 32a, and a new tool bit 31 is attached and then fixed by tightening the screw 32a. The configuration of the tool bit 31 is not limited to the embodiment shown in the figure. For example, a configuration corresponding to the tool bit body 31b shown in the figure may be fixed to the turning wheel 32, and only the tool bit cutting edge 31a may be replaceable. Furthermore, the cutting tool 31 may be provided with an angle adjustment means for adjusting the mounting angle of the cutting tool tip 31a.

[0022] Returning to Fig. 1, the illustrated processing device 1 is equipped with a vertical feed means 38 that raises and lowers a moving base 37 of the tool bit means 3 along the guide rails 22, 22. The vertical feed means 38 is equipped with a pulse motor 38a, a male screw rod 38b that is disposed in the vertical direction parallel to the guide rails 22, 22, rotatably supported by the support wall 21, and rotated by the pulse motor 38a, and a female screw block (not shown) that is attached to the moving base 37 and screws into the male screw rod 38b, and the male screw rod 38b is driven in forward and reverse directions by the pulse motor 38a to move the tool bit means 3 in the Z-axis direction (up and down direction).

[0023] The holding means 5 includes a cover table 51 and a chuck table 52 disposed at the center of the cover table 51 so as to protrude upward. A suction means (not shown) is connected to the chuck table 52, and by operating the suction means, a negative pressure can be generated on the holding surface on which the wafer W is held. A parallel feed means (not shown) for moving the chuck table 52 in the Y-axis direction indicated by the arrow Y and in a direction parallel to the horizontal plane is disposed in the device housing 2, and the chuck table 52 can be moved between a carry-in / out area on the front side in the Y-axis direction and a turning area directly below the tool bit means 3. The chuck table 52 does not rotate, but may be rotatable. However, when the wafer W is held on the chuck table 52 and the front surface Wa is turned, the chuck table 52 is not rotated.

[0024] When performing turning processing using the above-mentioned processing device 1, it is necessary to accurately control the height of the cutting edge tip 31d of the cutting tool cutting edge 31a, and a cutting edge height detection means (not shown) arranged near the chuck table 52 is used to detect the height of the cutting edge tip 31d. When detecting the height of the cutting edge tip 31d, the vertical feed means 38 is operated to lower the cutting tool means 3, and the turning wheel 32 is rotated to rotate the cutting edge tip 31d of the cutting tool cutting edge 31a and pass through the detection area of ​​the cutting edge height detection means. This makes it possible to accurately detect the height position of the cutting edge tip 31d, and the detected height position of the cutting edge tip 31d is stored in the above-mentioned control means. By controlling the vertical feed means 38 with the detected height position of the cutting edge tip 31d as a reference position, the height of the cutting edge tip 31d of the cutting tool cutting edge 31a can be precisely controlled.

[0025] Incidentally, the width of the cutting edge tip 31d of the cutting tool cutting edge 31a is, for example, about 20 μm, and even if the above-mentioned cutting edge height detection means is used, it is not possible to detect whether or not part of the cutting edge tip 31d of the cutting tool cutting edge 31a is chipped or partially worn. Therefore, the cutting edge condition inspection method configured based on the present invention described below is performed whenever it becomes necessary to check the condition of the cutting edge 31a, or periodically.

[0026] (Inspection wafer preparation process) When carrying out the cutting edge state inspection method of this embodiment, first, an inspection wafer preparation step is carried out to prepare an inspection wafer suitable for the cutting edge state inspection method configured based on the present invention. When preparing the inspection wafer, first, as shown in FIG. 3, a substrate 40 is prepared as a base of the inspection wafer having dimensions corresponding to the wafer W, which is the workpiece of the processing device 1. The substrate 40 is, for example, a circular silicon (Si) substrate formed with a thickness of 700 μm and a diameter of 300 mm. Although no devices or the like are formed on the substrate 40, for convenience of explanation, the upper surface of the substrate 40 shown in FIG. 3 is referred to as the front surface 40a, and the lower surface is referred to as the back surface 40b.

[0027] Once the above-described substrate 40 is prepared, the substrate 40 is transferred to a spinner table 60 shown in Fig. 3. The spinner table 60 includes a chuck table 61 having an air-permeable holding member 61a and a frame portion 61b surrounding the holding member 61a, a rotating shaft 62 supporting the chuck table 61 on the lower surface side, and an electric motor 63 rotating the rotating shaft 62. A suction means (not shown) is connected to the holding member 61a of the chuck table 61 via the rotating shaft 62. By operating the suction means, a negative pressure can be generated on the upper surface of the holding member 61a.

[0028] Once the substrate 40 has been transported to the spinner table 60, it is placed on the chuck table 61, and the suction means is activated to suck and hold the substrate 40 on the upper surface of the chuck table 61 (see FIG. 4).

[0029] Next, as shown in FIG. 4, the supply nozzle 72 of the water-soluble resin supplying means 70 (only a part of which is shown) is positioned above the center of the substrate 40 held on the spinner table 60. Then, the electric motor 63 of the spinner table 60 is operated to rotate the substrate 40 in the direction indicated by the arrow R1 at a predetermined rotation speed (for example, 2000 rpm). Next, while the substrate 40 is rotating, a predetermined amount of water-soluble resin 74 is dropped onto the surface 40a from the nozzle tip 72a of the supply nozzle 72. The water-soluble resin 74 is, for example, polyvinyl alcohol (PVA), but the present invention is not limited to this, and may be, for example, polyacrylamide (PAA). In this way, the water-soluble resin 74 is dropped onto the surface n40a of the substrate 40 and rotated for a predetermined time (for example, 90 seconds), thereby forming a water-soluble resin film 74' of a predetermined thickness (for example, 5 μm) made of the water-soluble resin 74 on the surface 40a of the substrate 40 (see FIG. 5). The water-soluble resin 74 may be dropped once, or may be dropped multiple times. Whichever method is used, it is important to finally form the resist film 84' to the desired thickness (preferably 2 to 5 μm). By setting the resist film 84' to the desired thickness, the resist film 84' can be well formed and well peeled off when the resist film peeling step is performed.

[0030] As described above, after the water-soluble resin film 74' is formed on the surface 40a of the substrate 40, a PMMA supplying means 80 (only a part of which is shown) that supplies a molten resist resin, for example, polymethyl methacrylate (PMMA) 84, is positioned above the center of the substrate 40 held on the spinner table 60, as shown in Fig. 5. After the PMMA supplying means 80 is positioned above the substrate 40 held on the spinner table 60, the electric motor 63 of the spinner table 60 is operated to rotate the spinner table 60 in the direction shown by the arrow R1, while a predetermined amount of molten PMMA 84 is dropped from the nozzle tip 82a of the supply nozzle 82 of the PMMA supplying means 80 to coat the substrate 40 on which the water-soluble resin film 74' has been formed, thereby forming a resist film 84' (see Fig. 6(a)). In this way, when the PMMA 84 is dropped from the nozzle tip 82a of the supply nozzle 82 to form the resist film 84' on the substrate 40, it is preferable to drop the PMMA 84 in several times while gradually changing the rotation speed of the spinner table 60 that suction-holds the substrate 40. For example, the substrate is first rotated in the direction indicated by the arrow R1 at a first rotation speed (e.g., 100 rpm), the first drop of PMMA 84 is applied and coated, and the substrate is rotated for 5 seconds, then rotated at a second rotation speed (e.g., 500 rpm), the second drop is applied and coated, and the substrate is rotated for 10 seconds, and further rotated at a third rotation speed (e.g., 1000 rpm), the third drop is applied and coated, and the substrate is rotated for 7 seconds. As a result, a resist film 84' with a uniform thickness of 30 μm is formed as shown in FIG. 6(b).

[0031] As a result of the above, as shown in Figures 6(a) and (b), a water-soluble resin film 74' and a resist film 84' are formed on the surface 40a of the substrate 40, completing the inspection wafer WA and completing the inspection wafer preparation process. Note that the thicknesses of the layers shown in Figure 6(b) are exaggerated for the sake of explanation and do not represent the actual thicknesses. Also, the above-mentioned inspection wafer preparation process is performed before the holding process, turning mark forming process, and inspection process described below are performed, and the inspection wafer WA is prepared in advance.

[0032] (holding process) The inspection wafer WA prepared by the above-mentioned inspection wafer preparation step is transported to the processing device 1 shown in Fig. 1, and the back surface of the inspection wafer WA (back surface 40b of the substrate 40) is held by the holding means 5 as shown in Fig. 7. More specifically, the inspection wafer WA is placed on the chuck table 52 of the holding means 5 positioned in the carry-in / out area with the side on which the resist film 84' is formed facing upward and the back surface 40b side of the substrate 40 facing downward, and the suction means (not shown) is operated to hold the wafer by suction, completing the holding step.

[0033] (Cutting mark formation process) After the holding step is performed as described above, the parallel feed means (not shown) is operated to move the holding means 5 to the turning area. At this time, the surface height of the inspection wafer WA is detected by a contact or non-contact height detection means (not shown) and stored in the control means. Next, the electric motor 35 of the cutting tool means 3 is operated to rotate the turning wheel 32 at a predetermined rotation speed (e.g., 6000 rpm), and the vertical feed means 38 is operated to position the resist film 84' formed on the surface of the inspection wafer WA at a height position where the resist film 84' formed on the surface of the inspection wafer WA is turned by about 10 μm. Then, as shown in FIG. 8(a), the chuck table 52 is moved by the parallel feed means at a predetermined speed (e.g., 1.9 mm / sec) in the direction indicated by the arrow Y1, and the surface of the inspection wafer WA, i.e., the resist film 84', is turned by the cutting tool 31 which is rotated in the direction indicated by R2 in the figure in accordance with the rotation of the turning wheel 32. For ease of explanation, the turning wheel 32 is omitted in FIG. 8(a), and only the cutting tool 31 is shown.

[0034] Since the rotation speed of the turning wheel 32 is 6000 rpm, the cutting tool 31 passes over the chuck table 52 100 times per second, and the chuck table 52 moves in the direction indicated by the arrow Y1 at a speed of 1.9 mm per second, so that the cutting edge tip 31d of the cutting tool 31 moves 19 μm per second in the Y-axis direction on the chuck table 52. Since the width of the cutting edge tip 31d of the cutting tool 31 is 20 μm, the entire resist film 84' formed on the upper surface of the inspection wafer WA is turned without any gaps. As a result, as shown in FIG. 8(b), the entire resist film 84' formed on the inspection wafer WA is turned to a depth of 10 μm, forming a plurality of arc-shaped turning marks 90, and the turning mark forming process is completed.

[0035] (Inspection process) As described above, after the turning mark forming step is performed and the turning marks 90 are formed on the resist film 84' of the inspection wafer WA, the turning marks 90 formed on the resist film 84' of the inspection wafer WA are inspected. The resist film 84' in this embodiment is formed of a resist resin (PMMA 84), which is a resin with extremely high hardness and transparency. For this reason, if there is a defect such as a chip in a part of the cutting edge tip 31d of the cutting tool cutting edge 31a, the surface of the resist film 84' is not turned smoothly, and the turning marks 90 are clearly visible due to the diffuse reflection of light at the turning marks 90. As a result, it is possible to easily determine whether there is a defect such as a chip or wear on the cutting edge tip 31d. Conversely, when the cutting edge tip 31d of the cutting tool cutting edge 31a is normal, the resist film 84' of the test wafer WA is smoothly turned, there is almost no diffuse reflection of light due to the turning marks 90, and the turning marks 90 are almost invisible, so that it can be determined that the cutting tool cutting edge 31a is in a proper state. Note that the turning marks 90 may be confirmed by visual inspection by an operator in the inspection process, but it may also be possible to image the surface of the test wafer WA with a camera or the like, determine the state of light reflection through image processing, and determine the state of light reflection through the control means described above. This completes the inspection process and the cutting edge condition inspection method of this embodiment.

[0036] As described above, by carrying out the turning mark forming step, the resist film 84 of the inspection wafer WA is turned to a depth of 10 μm, and turning marks 90 are formed. Here, as described above, the thickness of the resist film 84' formed when the inspection wafer WA is prepared is 30 μm, so 20 μm of the resist film 84' still remains. Therefore, the inspection wafer WA that has been subjected to the turning mark forming step and the inspection step can be repeatedly (a total of two times) used in the cutting edge state inspection method according to the present invention. In this way, by setting the thickness of the resist film 84' formed on the inspection wafer WA to be greater than twice the turning depth in the turning mark forming step, for example, 30 to 40 μm, the cutting edge state inspection method using the inspection wafer WA can be carried out multiple times.

[0037] (Resist film stripping process) When the above-mentioned inspection step is performed and the resist film 84' of the inspection wafer WA is turned to a thickness at which the turning mark forming step cannot be performed any further, the resist film peeling step described below is preferably performed. The resist film peeling step is a step of supplying water to the inspection wafer WA after the inspection step to dissolve the water-soluble resin film 74' from the substrate 40 described above and peeling off the resist film 84'. The resist film peeling step will be described in more detail with reference to FIG. 9.

[0038] When performing the resist film peeling step, a water supplying means 100 for supplying water to the test wafer WA as shown in FIG. 9(a) is prepared. The water supplying means 100 is configured to include a water tank 102 shown in cross section. A base 104 for adsorbing and supporting the test wafer WA is disposed in the water tank 102, and the water tank 102 is filled with pure water G. The back surface (the back surface 40b side of the substrate 40) of the test wafer WA that has completed the inspection step is adsorbed and supported by the base 104 in the water tank 102, and the resist film 84' side is exposed upward and immersed in the pure water G in the water tank 102. Over time, the water-soluble resin film 74' dissolves and the resist film 84' can be peeled off, but preferably, ultrasonic waves are applied as follows.

[0039] More specifically, the ultrasonic wave applying means 110 is submerged in the pure water G and brought close to the inspection wafer WA, and ultrasonic waves P of a predetermined frequency (for example, 20000 to 30000 Hz) are applied through the pure water G. As a result, the pure water G penetrates more efficiently from the side of the inspection wafer WA into the area of ​​the water-soluble resin film 74' between the substrate 40 and the resist film 84', dissolving the water-soluble resin film 74' and peeling off the resist film 84' as shown by the arrow R3 in the figure. When applying the ultrasonic waves P, it is preferable to move the ultrasonic wave applying means 110 in the direction shown by the arrow F to apply ultrasonic waves to the entire upper surface of the inspection wafer WA. As a result, as shown in FIG. 9(b), the substrate 40 from which the water-soluble resin film 74' and the resist film 84' have been removed is obtained. This substrate 40 can be reused by the above-mentioned inspection wafer preparation process.

[0040] The resist film peeling step is not limited to the above-mentioned one using the water tank 102 and the ultrasonic wave applying means 110. For example, a shower means (not shown) for spraying pure water G can be used to spray the pure water G onto the outer periphery of the inspection wafer WA that has completed the inspection step, thereby supplying the pure water G to the water-soluble resin film 74' between the resist film 84' and the substrate 40, and at the same time, vibrations are applied by the pure water G sprayed from the shower means to peel off the resist film 84'.

[0041] According to the above-described embodiment, in the processing apparatus 1 including the bit means 3 having the rotatable bit 31 for parallelly cutting the upper surface of the wafer W held by the holding means 5, the condition of the bit cutting edge 31a of the bit 31, such as chipping or wear of the cutting edge tip 31d, can be inspected, and the water-soluble resin film 74' can be dissolved with water (pure water G) to easily remove the resist film 84', eliminating the problem that it is necessary to take a considerable amount of time to remove the resist film 84' using acetone, which requires consideration for the safety of the worker, and is thus troublesome.

[0042] Furthermore, the inspection wafer WA formed according to the present invention described above has a water-soluble resin film 74' formed on the upper surface of the substrate 40, and a resist film is coated on top of the water-soluble resin film 74' to form a surface. Therefore, the condition of the cutting edge of the cutting edge 31a of the cutting edge 31 of the cutting edge 31, such as chipping or wear of the cutting edge tip 31d, can be inspected, and the water-soluble resin film 74' can be dissolved with water (pure water G) to easily remove the resist film 84'. This eliminates the problem that it is necessary to take a considerable amount of time to remove the resist film 84' using acetone, which requires consideration for the safety of the worker, and this is troublesome. [Explanation of symbols]

[0043] 1: Processing equipment 2: Device housing 3: Byte method 31: Byte 31a: cutting edge 31b: Byte body 31c: Fixing screw 31d: Tip of cutting edge 32: Turning wheel 33: Unit housing 34: Rotation axis 35: Electric motor 36: Support member 37: Mobile base 38: Vertical feed means 38a: Pulse motor 38b: Male threaded rod 5: Holding means 51: Cover table 52: Chuck table 6: First Cassette 7: Second Cassette 8: Alignment means 9: Cleaning method 10: First conveyance means 11: Second conveyance means 12: Third conveyance means 14: Operation panel 40: Substrate 70:Water-soluble resin supply means 72: Supply nozzle 72a: Nozzle tip 74: Water-soluble resin 74': Water-soluble resin film 80:PMMA supply means 82: Supply nozzle 82a: Nozzle tip 84: PMMA 84': Resist film 90: Turning marks 100: Water supply means 102: Aquarium 104: Foundation 110: Ultrasonic wave applying means W: Wafer WA: Wafer for inspection

Claims

1. A cutting edge condition inspection method for inspecting a cutting edge condition of a cutting tool in a processing device including a holding means for holding a plate-like object and a cutting tool means having a rotatable cutting tool for cutting a top surface of the plate-like object held by the holding means in parallel, comprising: a test wafer preparation step of preparing a test wafer having a surface configured by coating a water-soluble resin on an upper surface of a substrate to form a water-soluble resin film and coating a resist film on the water-soluble resin film; a holding step of holding the back surface of the inspection wafer on the holding means; a turning mark forming step of turning the front surface of the inspection wafer held by the holding means by rotating the bit of the bit means to form turning marks on the resist film; an inspection step of inspecting the cutting edge state of the cutting tool from the turning marks; A cutting edge condition inspection method comprising the steps of:

2. 2. The cutting edge condition inspection method according to claim 1, further comprising a resist film stripping step of supplying water to the inspection wafer after the inspection step to dissolve the water-soluble resin film from the substrate and strip the resist film.

3. 3. The method for inspecting a cutting edge condition according to claim 2, wherein the ultrasonic wave is applied via water in the resist film removing step.

4. 3. The method for inspecting a cutting edge state according to claim 2, wherein the substrate is reused after the water-soluble resin film is dissolved from the substrate and the resist film is peeled off.

5. The inspection wafer has a surface constructed by coating a water-soluble resin on the upper surface of a substrate to form a water-soluble resin film, and then coating a resist film on the water-soluble resin film.

6. 6. The inspection wafer according to claim 5, wherein the substrate is a silicon substrate, the water-soluble resin film has a thickness of 2 to 5 μm, and the resist film has a thickness of 30 to 40 μm.

Images