Processing apparatus and processing method

Abstract

The present invention provides a processing apparatus capable of appropriately cutting chamfered portions from the surface of a wafer. [Solution] A processing apparatus comprising at least a cutting means for cutting a chamfered portion Wc and a control means, wherein the apparatus includes an X-axis moving means for moving a chuck table 7 in the X-axis direction, a Y-axis moving means for moving the cutting means in the Y-axis direction perpendicular to the X-axis direction, and a measuring means 10 for measuring the thickness of the chamfered portion Wc cut by the cutting means, the chuck table having a holding surface defined by the X-axis and Y-axis and a rotation axis C1 at a position defined by coordinate C1(X1,Y1), the measuring means 10 being mounted at a position defined by coordinate C2(X2,Y2), and the control means positioning the measuring means at a desired position on the wafer W held on the chuck table based on coordinates C1(X1,Y1) and C2(X2,Y2).

Description

[Technical Field]

[0001] The present invention relates to a processing apparatus comprising at least a chuck table that holds and rotates a wafer, cutting means for positioning a cutting blade on the outer circumference of the wafer held on the chuck table to cut a chamfered portion, and control means, and a processing method for processing a wafer using the processing apparatus. [Background technology]

[0002] A wafer, on which multiple devices such as ICs and LSIs are divided by planned division lines and formed on its surface, is then ground on its back surface to form a predetermined thickness. After that, it is divided into individual device chips by a dicing machine and used in electrical equipment such as mobile phones and personal computers.

[0003] The grinding apparatus comprises a chuck table for holding a wafer, a grinding means equipped with a rotatable grinding wheel having grinding wheels arranged in an annular shape for grinding the wafer held on the chuck table, a feeding means for grinding and feeding the grinding means, and a measuring means for measuring the thickness of the wafer, and can process a wafer to a desired thickness.

[0004] However, a chamfered edge is formed on the outer edge of the wafer. When the back surface of the wafer is ground down to thin it, the chamfered edge becomes a sharp knife edge, causing cracks to form from the outer edge. These cracks can reach the central device area where multiple devices are formed, damaging the devices and potentially injuring the operator.

[0005] Therefore, in order to address the above-mentioned problems, the applicant has proposed a technique for removing the chamfered portion before grinding the back surface of the wafer (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2016-096295 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, in the case of a two-layer wafer formed by stacking two wafers, before stacking the two wafers, the chamfered portion of one wafer, whose back surface is ground, is sometimes removed, and then the surface of the wafer from which the chamfer has been removed is placed facing the other wafer. In this case, if the chamfered portion of the one wafer is completely removed, it becomes difficult to accurately align the center of the other wafer with the center of the one wafer with the smaller diameter from which the chamfer has been removed. Therefore, it is necessary to leave more than half of the chamfered portion of the one wafer. However, in this case, while leaving more than half of the chamfered portion of the one wafer, the chamfered portion is cut and removed from the surface of the one wafer in a manner that slightly exceeds the finished thickness obtained by grinding the back surface of the one wafer, which presents the problem of difficulty in precisely cutting and removing the chamfered portion.

[0008] The present invention has been made in view of the above facts, and its main technical problem is to provide a processing apparatus that can appropriately cut the chamfered portion from the surface of a wafer so as to slightly exceed the finished thickness obtained by grinding the back surface of the wafer, after positioning a cutting blade on the chamfered portion of the wafer to form a stepped portion (cutting groove) on the outer circumference, and then positioning a measuring means in an appropriate position to measure the remaining thickness of the chamfered portion, and a processing method for processing a wafer using the processing apparatus. [Means for solving the problem]

[0009] To solve the above-mentioned main technical problems, the present invention provides a processing apparatus comprising at least a chuck table that can hold and rotate a wafer, a cutting means for positioning a cutting blade on the outer circumference of the wafer held on the chuck table to cut a chamfered portion, and a control means, wherein the processing apparatus comprises an X-axis moving means for moving the chuck table in the X-axis direction, a Y-axis moving means for moving the cutting means in the Y-axis direction perpendicular to the X-axis direction, and a measuring means for measuring the thickness of the chamfered portion cut by the cutting means, the chuck table having a holding surface defined by the X-axis and Y-axis and a rotation axis at a position defined by coordinate (X1, Y1), the measuring means being mounted at a position defined by coordinate (X2, Y2), and the control means positioning the measuring means at a desired position on the wafer held on the chuck table based on coordinate (X1, Y1) and coordinate (X2, Y2).

[0010] The Y-axis movement means is operated on the outer circumference of the wafer held on the chuck table to position the cutting blade at a predetermined distance H from the coordinates (X1, Y1) of the rotation axis, and the chuck table is rotated to form an annular cutting groove on the outer circumference of the wafer, and the control means operates the X-axis movement means to position the coordinates (X3, Y2) of the first position and the coordinates (X4, Y2) of the second position of the cutting groove directly below the measuring means, {H 2 -[(X4-X3) / 2] 2} -2 The value of Y2 is determined by this method. (X3 + X4) / 2 It is preferable to determine the value of X2 and use it as the coordinate (X2, Y2) of the measuring means.

[0011] Furthermore, when a cutting groove formed on the outer circumference of a wafer held on the chuck table is formed at a radius R from the coordinates (X1, Y1) of the rotation axis, the control means shall Rsinθ=Y² Find θ such that The rotation axis of the chuck table is X2 - (Rcosθ + α) (α is the region to be detected) It is preferable to position the region to be detected directly below the measuring means by positioning it at a position defined by .

[0012] Also, according to the present invention, there is provided a processing method for processing a wafer by the above-described processing apparatus, including: a cutting groove forming step of forming an annular cutting groove on the outer periphery of the wafer held on the chuck table by operating the Y-axis direction moving means to position the cutting blade at a position of a predetermined distance H from the coordinates (X1, Y1) of the rotation axis and rotating the chuck table; and a positioning step of operating the X-axis direction moving means to position the coordinates (X3, Y2) of the first position and the coordinates (X4, Y2) of the second position of the cutting groove directly below the measuring means, {H 2 -[(X4 - X3) / 2] 2} -2 to obtain the coordinate Y2, (X3 + X4) / 2 to obtain the coordinate X2, and a measuring means coordinate calculation step of obtaining the coordinates (X2, Y2) of the measuring means.

Effects of the Invention

[0013] The processing apparatus of the present invention is a processing apparatus configured to include at least a chuck table that holds a wafer and is rotatable, cutting means for positioning a cutting blade on the outer periphery of the wafer held by the chuck table to cut a chamfered portion, and a control means. The processing apparatus includes X-axis direction moving means for moving the chuck table in the X-axis direction, Y-axis direction moving means for moving the cutting means in the Y-axis direction orthogonal to the X-axis direction, and measuring means for measuring the thickness of the chamfered portion cut by the cutting means. The chuck table includes a holding surface defined by the X-axis and the Y-axis, and has a rotation axis at a position defined by coordinates (X1, Y1). The measuring means is attached at a position defined by coordinates (X2, Y2). The control means positions the measuring means at a desired position of the wafer held by the chuck table based on the coordinates (X1, Y1) and the coordinates (X2, Y2). After positioning the cutting blade on the chamfered portion of the wafer to form a cutting groove (step portion), the measuring means for measuring the thickness based on the coordinates is positioned at an appropriate position to measure the remaining thickness of the chamfered portion, and it becomes possible to appropriately cut the chamfered portion from the surface of the wafer so as to slightly exceed the finished thickness obtained by grinding the back surface of the wafer.

[0014] Further, the processing method of the present invention is a processing method for processing a wafer by the above-described processing apparatus. In a cutting groove forming step, the Y-axis direction moving means is operated to position the cutting blade at a position of a predetermined distance H from the coordinates (X1, Y1) of the rotation axis on the outer periphery of the wafer held by the chuck table, and the chuck table is rotated to form an annular cutting groove on the outer periphery of the wafer. In a positioning step, the X-axis direction moving means is operated to position the coordinates (X3, Y2) of the first position and the coordinates (X4, Y2) of the second position of the cutting groove directly below the measuring means. {H 2 -[(X4 - X3) / 2] 2} -2 to obtain the coordinate Y2, (X3 + X4) / 2 The process includes a step of calculating the coordinates of the measuring means, which involves determining the coordinates X2 and the coordinates (X2, Y2) of the measuring means. This makes it possible to position a cutting blade on the chamfered portion of the wafer to form a cutting groove (step), and then position a measuring means that measures the thickness based on these coordinates in an appropriate position to measure the remaining thickness of the chamfered portion. This makes it possible to appropriately cut the chamfered portion from the surface of the wafer so that it slightly exceeds the finished thickness obtained by grinding the back surface of the wafer. [Brief explanation of the drawing]

[0015] [Figure 1] This is an overall perspective view of the processing apparatus of this embodiment. [Figure 2] This is a conceptual diagram showing the positions of the chuck table and measuring means of the processing apparatus shown in Figure 1. [Figure 3] This is a plan view showing a dummy wafer held in place on a chuck table. [Figure 4] (a) A plan view showing a cutting process in which cutting grooves are formed on the outer circumference of a dummy wafer, and (b) A partially enlarged cross-sectional view showing the cutting process shown in (a). [Figure 5] (a) A plan view showing the cutting groove formed in a dummy wafer, and (b) A partially enlarged cross-sectional view showing the cutting groove of the dummy wafer shown in (a). [Figure 6] (a) A plan view showing the measuring means positioned at the first position of the cutting groove on the dummy wafer, and (b) A partially enlarged cross-sectional view showing the state shown in (a). [Figure 7] (a) A plan view showing the measuring means positioned at the second position of the cutting groove in the dummy wafer, and (b) A partially enlarged cross-sectional view showing the state shown in (a). [Figure 8] This is a plan view showing a configuration in which a measuring device is positioned within the measurement area of ​​a cutting groove on a wafer. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments relating to a processing apparatus configured according to the present invention and a processing method for processing wafers using the processing apparatus will be described in detail with reference to the attached drawings.

[0017] Figure 1 shows an overall perspective view of a dicing apparatus 1, which is an example of a processing apparatus of the present invention. The dicing apparatus 1 of this embodiment is a processing apparatus that performs cutting on a wafer W as shown in the figure. The wafer W has a surface Wa and a back surface Wb, and a plurality of devices D are formed on the surface Wa, partitioned by lines to be divided, and a chamfered portion Wc is formed on the outer circumference. The dicing apparatus 1 comprises at least a chuck table 7 that holds the wafer W and is rotatable by a rotational drive means (not shown), a cutting means 8 that positions a cutting blade 81 on the outer circumference of the wafer W held on the chuck table 7 to cut the chamfered portion Wc, and a control means 20. The chuck table 7 is made of a breathable material and comprises a holding surface 7a defined by the X axis and the Y axis perpendicular to the X axis, and a frame 7b surrounding the holding surface 7a. The frame 7b is connected to a suction means (not shown), and the suction means can generate negative pressure on the holding surface 7a.

[0018] The illustrated dicing apparatus 1 includes an X-axis moving means (not shown) that moves the chuck table 7 in the X-axis direction indicated by arrow X in the figure, and a Y-axis moving means (not shown) that moves the cutting means 8 in the Y-axis direction perpendicular to the X-axis direction. It also includes a non-contact measuring means 10 capable of measuring the thickness (height) of the wafer W held on the chuck table 7, and the measuring means 10 is positioned in a desired area of ​​the chamfered portion Wc cut by the cutting means 8 to measure the thickness of that area.

[0019] The dicing apparatus 1 includes a housing 2 with a substantially rectangular parallelepiped shape, and at a position adjacent to the measuring means 10 in the Y-axis direction, an alignment means 11 that performs alignment by imaging a workpiece held on the chuck table 7 to detect the area to be cut; a cassette 3a placed on a cassette table 3 of the housing 2; an loading / unloading means 4 that loads an unprocessed wafer W from the cassette 3a onto a temporary storage table 5; a transport means 6 having a swivel arm that transports the wafer W loaded onto the temporary storage table 5 to the chuck table 7; a cleaning / unloading means 13 that transports the wafer W from the loading / unloading position where the chuck table 7 is positioned in Figure 1 to a cleaning apparatus 12; and a display means 14.

[0020] In addition to the X-axis movement means and Y-axis movement means described above, the dicing apparatus 1 is equipped with a Z-axis movement means that feeds the cutting means 8 in the Z-axis direction (vertical direction), which is perpendicular to the X-axis and Y-axis directions. The X-axis movement means, Y-axis movement means, and Z-axis movement means are all located inside the housing 2 and are not shown in the diagram.

[0021] The control means 20 is composed of a computer and includes a central processing unit (CPU) that performs calculations according to a control program, a read-only memory (ROM) for storing the control program and the like, a read-write random access memory (RAM) for temporarily storing values ​​measured by the dicing device 1, calculation results, and the like, as well as an input interface and an output interface (details are not shown in the illustration). At least the X-axis movement means, Y-axis movement means, Z-axis movement means, cutting means 8, rotational drive means for the chuck table 7, measuring means 10, alignment means 11, display means 14, etc. are connected to the control means 20 and are operated by a plurality of control programs stored in the control means 20. In Figure 1, the control means 20 is shown outside the housing 2 for illustrative purposes, but in reality it is located inside the housing 2.

[0022] As shown in Figure 2, the chuck table 7 has a rotation axis C1 defined by coordinates C1(X1,Y1) at the center of the chuck table 7, and the measuring means 10 is positioned at a location defined by coordinates C2(X2,Y2). In the dicing apparatus 1 of this embodiment, the chuck table 7 is moved in the X-axis direction by the control means 20, so the control means 20 positions the measuring means 10 at a desired position on the wafer W held by the chuck table 7 based on the coordinates C1(X1,Y1) of the rotation axis C1 of the chuck table 7 and the coordinates C2(X2,Y2) of the measuring means 10.

[0023] Here, although the coordinates C1(X1,Y1) of the rotation axis C1 of the chuck table 7 in this embodiment are known, the position C2 where the measuring means 10 is attached in the dicing device 1 may not be accurately known due to maintenance, replacement, etc. In order to reliably measure the thickness (height) of a desired area of ​​the wafer W held on the chuck table 7, for example, the area where a part of the chamfered portion Wc has been removed, it is necessary to accurately know the position of the measuring means 10 in the dicing device 1. Therefore, the control means 20 of the dicing device 1 in this embodiment obtains and stores the coordinates C2(X2,Y2) that define the position where the measuring means 10 is installed, for example, by following the procedure below. Note that the method for accurately determining the coordinates C2(X2,Y2) indicating the position of the measuring means 10 is not limited to the method described below, and it is possible to determine it by various methods.

[0024] In order to accurately determine the coordinates C2(X2,Y2) indicating the position of the measuring means 10, first, as shown in Figure 3, a dummy wafer WD is prepared with dimensions suitable for placement on the chuck table 7, for example, the same dimensions as the wafer W described above, and placed on the chuck table 7 to generate negative pressure on the holding surface 7a described above and hold it by suction. The surface WDa of the dummy wafer WD does not have a device D formed on it like the wafer W described above, and a chamfered portion WDc is formed on its outer circumference.

[0025] Next, as shown in Figure 4(a), the chuck table 7 holding the dummy wafer WD is positioned directly below the cutting means 8, and the Y-axis movement means described above is activated to position the cutting blade 81 of the cutting means 8 at a predetermined distance H from the coordinates C1(X1,Y1) of the rotation axis C1 of the chuck table 7. This H is set to a predetermined width smaller than the radius R0 of the dummy wafer WD, for example, 5 mm. Then, the rotation axis 8a to which the cutting blade 81 of the cutting means 8 is attached is rotated at high speed, and the chuck table 7 is rotated in the direction indicated by arrow R1, and the cutting means 8 is fed toward the dummy wafer WD to cut the chamfered portion WDc formed on the outer circumference of the dummy wafer WD, as shown in Figures 4(a) and (b). At this time, the chamfered portion WDc of the dummy wafer WD is not completely removed, and as shown in Figure 4(b), a part of the chamfered portion WDc, more specifically, more than half of the thickness of the chamfered portion WDc remains after cutting. As described above, the cutting groove forming process is performed by operating the Y-axis moving means to position the cutting blade 81 at a predetermined distance H from the rotation axis coordinates C1(X1, Y1) on the outer circumference of the dummy wafer WD held in the chuck table 7, and rotating the chuck table 7 to form an annular cutting groove WDd on the outer circumference of the dummy wafer WD. As shown in Figures 5(a) and (b), an annular cutting groove WDd with radius H centered at the rotation axis C1(X1, Y1) of the chuck table 7 is formed on the outer circumference of the dummy wafer WD. Note that the shapes of the configurations shown in Figures 4 and 5 above, and further in Figures 6-8 described below, are exaggerated for illustrative purposes and do not correspond to the actual dimensional ratios.

[0026] As described above, once an annular cutting groove WDd with radius H centered on the rotation axis C1 of the chuck table 7 is formed, the X-axis moving means described above is activated to move the chuck table 7 in the direction indicated by the arrow R2 in the X-axis direction, as shown in Figures 6(a) and (b), while the thickness is measured by the measuring means 10, and the first position P1 of the cutting groove WDd is detected. The first position P1 is the position at the center of the measuring means 10 where, when the chuck table 7 is moved in the X-axis direction as shown in the figure, a step difference is detected between the cutting groove WDd on one side of the dummy wafer WD and the surface WDa of the dummy wafer WD. As a result, the X coordinate X3 of the first position P1 is detected, and the value of the X coordinate X3 of the first position P1 is stored in a predetermined memory of the control means 20.

[0027] After positioning the first position P1 described above directly below the measuring means 10 and detecting the X coordinate, as shown in Figures 7(a) and (b), the X-axis movement means described above is further operated to move the chuck table 7 in the direction indicated by arrow R2 in the X axis direction, while measuring the thickness of the dummy wafer WD with the measuring means 10, and detecting the second position P2 of the cutting groove WDd that reappears directly below the measuring means 10. As shown in the figure, the second position P2 is the position at the center of the measuring means 10 where a step difference is detected between the cutting groove WDd on the other side of the dummy wafer WD and the surface WDa of the dummy wafer WD, and the X coordinate X4 of the second position P2 is determined. The X coordinate X4 of this second position P2 is also stored in a predetermined memory of the control means 20. As described above, by operating the X-axis moving means and performing a positioning step to position the coordinates (X3, Y2) of the first position P1 and the coordinates (X4, Y2) of the second position P2 of the cutting groove WDd directly below the measuring means 10, the X coordinate X3 of the first position P1 and the X coordinate X4 of the second position P2 are detected.

[0028] After performing the cutting groove formation process and positioning process described above, a measurement means coordinate calculation process is performed to determine the coordinates (X2, Y2) of the measurement means 10 as shown below. More specifically, the coordinates C2(X2, Y2) of the measurement means 10 can be calculated based on the following equations (a) and (b) using the X coordinate X3 of the first position P1 and the X coordinate X4 of the second position P2 described above. The value of these coordinates C2(X2, Y2) is stored in the control means 20.

[0029] X2 = (X3 + X4) / 2 ... (A) Y2={H 2 -[(X4-X3) / 2] 2} -2 ······(stomach)

[0030] The coordinates C2(X2,Y2) of the measuring means 10, calculated based on the above-mentioned equations (a) and (b), were obtained by actually measuring the cutting groove WDd, which is formed at an equal distance H from the known coordinates C1(X1,Y1) of the rotation axis of the chuck table 7, using the measuring means 10. Based on the coordinates C1(X1,Y1) of the rotation axis C1 of the chuck table 7 and the coordinates C2(X2,Y2) of the measuring means 10 described above, it is possible to accurately position the area to be detected on the chuck table 7 directly below the measuring means 10.

[0031] For example, a wafer W as shown in Figure 1 is prepared, placed on the chuck table 7 and held by suction, and following the cutting procedure described based on Figure 4, the cutting blade 81 of the cutting means 8 described above is positioned on the chamfered portion Wc on the outer circumference of the wafer W held on the chuck table 7 to form a cutting groove Wd at a radius R from the rotation axis C1 of the chuck table 7 (see Figure 8). The thickness of the cutting groove Wd thus formed is measured based on the coordinates C1(X1,Y1) of the rotation axis C1 of the chuck table 7 and the coordinates C2(X2,Y2) of the measuring means 10 described above, according to the procedure described below. Note that Figure 8 shows only a part of the wafer W held on the chuck table 7, and for the sake of explanation, the device D formed on the surface Wa is omitted.

[0032] First, the control means 20 uses the above equation (a) and the following equation Rsinθ=Y²······(U) Based on this, the angle θ that satisfies equation (c) above is calculated. The angle θ obtained by equation (c) above is the angle θ that matches the Y coordinate of the measurement means 10 described above when the X-axis moving means is operated to move the rotation axis C1 of the chuck table 7 in the X-axis direction, a half-line is drawn with the rotation axis C1 as the origin and the angle with respect to the X-axis direction is θ, as shown in Figure 8, and the Y coordinate of the intersection point P3 where the half-line intersects with the boundary between the surface Wa of the wafer W and the cutting groove Wd is the Y coordinate Y2 of the measurement means 10 described above. Then, in order to measure the thickness of the cutting groove Wd, the measurement means 10 is positioned in a desired region (indicated by α in the figure) that is α away in the X-axis direction from the intersection point P3 so that the thickness within the cutting groove Wd can be reliably detected. More specifically, the X coordinate position where the rotation axis C1 of the chuck table 7 is positioned is determined based on the X coordinate X2 of the measurement means 10 based on equation (a) above and the angle θ above, X2-(Rcosθ+α)····(d) The calculation is performed by the following equation (E). By positioning the rotation axis C1 of the chuck table 7 at the X coordinate calculated by this equation (E), the measuring means 10 can be positioned in a desired region on the wafer W held by the chuck table 7, at a distance of α in the X-axis direction from the intersection P3 where the thickness to be detected is to be detected, thereby reliably measuring the thickness of the cutting groove Wd.

[0033] According to the above-described embodiment of the processing apparatus and processing method, after positioning the cutting blade 81 in the chamfered portion Wc of the wafer W to form a cutting groove Wd that forms a step, it becomes possible to position the measuring means 10 in an appropriate position based on the above-described X coordinate to measure the remaining thickness of the chamfered portion Wc, and it becomes possible to cut into the chamfered portion Wc from the surface Wa side of the wafer W so as to slightly exceed the finished thickness obtained by grinding the back surface of the wafer W.

[0034] The method for determining the coordinates C2(X2,Y2) of the measuring means 10 based on the present invention is not limited to the method described above. In the method described above, a dummy wafer WD is prepared and held by a chuck table 7, a cutting blade 81 is positioned at a predetermined distance H from the rotation axis C1 of the chuck table 7, and the outer circumference of the dummy wafer WD is cut while rotating the chuck table 7 to form an annular cutting groove WDd at a certain distance H from the rotation axis C1 of the chuck table 7, and the coordinates of the position C2 of the measuring means 10 are determined based on the positions of the first position P1 and the second position P2 described above. However, the present invention is not limited to this, and it is possible to determine the coordinates in various ways, for example, as follows.

[0035] In the method described below, it is not necessary to cut the outer circumference of the wafer placed on the chuck table 7 to form cutting grooves when determining the position of the measuring means 10. Therefore, the wafer placed on the chuck table 7 when determining the position of the measuring means 10 does not need to be a dummy wafer WD, and the wafer W that is the workpiece may be used as is.

[0036] First, in the dicing apparatus 1 shown in Figure 1, a wafer W with radius R0 is placed on the chuck table 7 at the loading / unloading position where the chuck table 7 is positioned, and held in place by suction. Next, while performing measurements with the measuring means 10, the X-axis movement means described above is activated to move the chuck table 7 in the X-axis direction to the side where the measuring means 10 is located, and the measuring means 10 detects the X coordinate X11 of the outer edge of one end of the wafer W. The value of the X coordinate X11 thus detected is stored in an appropriate memory of the control means 20.

[0037] Furthermore, the X-axis movement mechanism is activated to move the chuck table 7 in the X-axis direction, and the measurement mechanism 10 detects the X-coordinate X12 of the outer edge on the other end of the wafer W. The value of the X-coordinate X12 detected in this way is also stored in an appropriate memory of the control mechanism 20.

[0038] From the above coordinates X11 and X12, the X coordinate of the center C3 of wafer W is calculated by the following equation (O). (X11+X12) / 2······(O)

[0039] Furthermore, the Y-coordinate of the center C3 of wafer W can be expressed as follows, given that the Y-coordinate of the unknown measurement means 10 is Y2, as shown in equation (k). Y2-{R0 2 -[(X11-X12) / 2] 2} -2 ······(mosquito)

[0040] Here, in contrast to the embodiment described earlier, in this embodiment, the position of the measuring means 10 is determined without forming cutting grooves on the outer circumference of the wafer W. Therefore, the misalignment between the position of the rotation axis C1 of the chuck table 7 and the center C3 (not shown) of the wafer W held by the chuck table 7 becomes a problem. The amount of misalignment of the center C3 of the wafer W with respect to the rotation axis C1 of the chuck table 7 in the X-axis direction and the Y-axis direction is unknown. If the angle between the straight line r connecting the rotation axis C1 of the chuck table 7 and the center C3 of the wafer W and the straight line r with respect to the X-axis direction is θ, then it can be expressed as shown in the following equations (Ki) and (Ku). x = rcosθ ······(Ki) y=rsinθ ······(Ku)

[0041] Since the coordinates C1(X1,Y1) of the rotation axis of the chuck table 7 are known, and the coordinates C2(X2,Y2) of the center position C2 of the measuring means 10 are unknown, the coordinates C2(X2,Y2) of the measuring means can be expressed as follows, based on the above-mentioned coordinates X11 and X12, and the displacement between the rotation axis C1 of the chuck table 7 and the center C3 of the wafer W (see equations (Ki) and (Ku) above). X² = rcosθ + (X¹¹ + X¹²) / 2 ... (Ke) Y² = rsinθ + {R₀ 2 -[(X11-X12) / 2] 2} -2 ·····(Ko)

[0042] Here, since rcosθ and rsinθ are unknown, in order to determine X2 and Y2, the chuck table 7 is rotated by a predetermined angle (β), and the same process as above to determine coordinates X11 and X12 is performed. The measurement means 10 detects the X coordinate X13 of the outer edge on one end of the wafer W in the X-axis direction and the X coordinate X14 of the outer edge on the other end of the wafer W in the X-axis direction, and stores them in an appropriate memory of the control means 20. Note that the predetermined angle (β) can be a relatively small angle, for example, about 10 degrees.

[0043] By rotating the chuck table 7 described above by a predetermined angle β, the coordinates C2(X2,Y2) of the measuring means 10 can be shown as follows, based on the newly detected X coordinate X13 of the outer edge of one end and the X coordinate X14 of the outer edge of the other end in the X-axis direction of the wafer W. X2=rcos(θ-β)+(X13+X14) / 2...(Sa) Y² = rsin(θ - β) +{R0 2 -[(X13-X14) / 2] 2} -2 ...(shi)

[0044] From the above equations (Ke) and (Sa) that show the coordinates of X2, rcosθ+(X11+X12) / 2 =rcos(θ-β)+(X13+X14) / 2 ·····(S) This leads to the conclusion.

[0045] Furthermore, from the above equations (Ko) and (Shi) that show the coordinates of Y2, rsinθ+{R0 2 -[(X11-X12) / 2] 2} -2 =rsin(θ-β)+{R0 2 -[(X13-X14) / 2] 2} -2 ··(se) This leads to the conclusion.

[0046] In the two equations (S) and (Se) described above, all variables except r and θ are known, so the unknown variables r and θ can be determined. These are stored in the control means 20. Then, by substituting the r and θ stored in the control means 20 into the equations (Ke) and (Ko) described above, the coordinates C2(X2,Y2) of the measuring means 10 can be determined. The same result can be obtained by substituting them into the equations (Sa) and (Shi) described above. By determining the coordinates C2(X2,Y2) of the measuring means 10 in this way, similar to the embodiment described earlier, the control means 20 can position the measuring means 10 at a desired position on the wafer W held by the chuck table 7, more specifically in a desired area within the cutting groove Wd formed on the outer circumference, based on the coordinates C1(X1,Y1) of the rotation axis C1 of the chuck table 7 and the coordinates C2(X2,Y2) of the measuring means 10, and measure the thickness.

[0047] The method for determining the coordinates C2(X2,Y2) indicating the position of the measurement means 10 described above is not limited to the method described above. For example, the dummy wafer WD described above is placed on the chuck table 7 of the dicing device 1 and held by suction, and the cutting blade 81 of the cutting means 8 is positioned at predetermined distances H1 and H2 from the rotation axis C1 of the chuck table 7, which is known, and while moving the chuck table 7 in the X-axis direction, a plurality of linear cutting grooves are formed on the dummy wafer WD. The positions where these linear cutting grooves are formed are known. Then, the chuck table 7 is rotated so that the linear cutting grooves are oriented in the Y-axis direction, and the X-axis direction moving means is activated to position the cutting grooves in the measurement means 10 and detect the cutting grooves formed on the dummy wafer WD. In this way, the coordinates C2(X2,Y2) of the position C2 of the measurement means 10 can be determined based on the rotation angle of the chuck table 7 and the plurality of X coordinates where the cutting grooves are detected. [Explanation of Symbols]

[0048] 1: Dicing device 2: Housing 3: Cassette Table 3a: Cassette 4: Carrying in / out means 5: Temporary placement table 6: Conveying means 7: Chuck Table 7a: Holding surface 7b: Frame 8: Cutting means 8a: Rotation axis 81: Cutting blade 10: Measuring means 11: Alignment Methods 12: Washing equipment 13: Washing and conveying means 14:Display means 20: Control means C1: Rotation axis D: Device W: Waha Wa: Surface Wb:Back side Wc: Chamfered part Wd: Cutting groove WD: Dummy wafer WDa: Surface WDc: Chamfered part WDd: Cutting groove

Claims

1. A processing apparatus comprising at least a chuck table that holds and rotates a wafer, cutting means for positioning a cutting blade on the outer circumference of the wafer held on the chuck table to cut a chamfered portion, and control means, X-axis movement means for moving the chuck table in the X-axis direction, A Y-axis moving means that moves the cutting means in the Y-axis direction perpendicular to the X-axis direction, The cutting means comprises a measuring means for measuring the thickness of the chamfered portion cut by the cutting means, The chuck table has a holding surface defined by the X and Y axes, and a rotation axis at a position defined by coordinates (X1, Y1). The measuring means is mounted at a position defined by the coordinates (X2, Y2), The control means is a processing apparatus that positions the measuring means at a desired position on the wafer held in the chuck table based on the coordinates (X1, Y1) and (X2, Y2).

2. The Y-axis movement mechanism is operated on the outer circumference of the wafer held on the chuck table to position the cutting blade at a predetermined distance H from the coordinates (X1, Y1) of the rotation axis, and the chuck table is rotated to form an annular cutting groove on the outer circumference of the wafer. The control means is, The X-axis movement means is activated to position the coordinates of the first position (X3, Y2) and the second position (X4, Y2) of the cutting groove directly below the measuring means. {H ２ -[(X4-X3) / 2] ２ } －２ The value of Y2 is determined by this, (X3 + X4) / 2 The processing apparatus according to claim 1, wherein the value of X2 is determined by this and the coordinates (X2, Y2) of the measuring means are set.

3. When a cutting groove formed on the outer circumference of a wafer held on the chuck table is formed at a position with radius R from the coordinates (X1, Y1) of the rotation axis, The control means finds θ such that Rsinθ = Y², The rotation axis of the chuck table is X² - (Rcosθ + α) (α is the region to be detected) The processing apparatus according to claim 2, wherein the measurement means is positioned at a position defined by the measurement means, and the area to be detected is positioned directly below the measurement means.

4. A processing method for processing a wafer using the processing apparatus described in claim 1, A cutting groove forming step is performed by operating the Y-axis moving means to position the cutting blade at a predetermined distance H from the coordinates (X1, Y1) of the rotation axis on the outer circumference of the wafer held on the chuck table, and then rotating the chuck table to form an annular cutting groove on the outer circumference of the wafer. A positioning step involves operating the X-axis moving means to position the coordinates of the first position (X3, Y2) and the coordinates of the second position (X4, Y2) of the cutting groove directly below the measuring means. {H ２ -[(X4-X3) / 2] ２ } －２ The coordinate Y2 is determined by this, (X3 + X4) / 2 A processing method comprising: a step of calculating the coordinates of a measuring means, which involves determining the coordinates X2 and the coordinates (X2, Y2) of the measuring means.

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