Wafer processing equipment

Abstract

To provide a wafer processing apparatus that can improve the efficiency of wafer measurement. [Solution] The wafer processing apparatus 10 comprises a measuring table 82 that holds the wafer 40 and is configured to be rotatable, a first sensor 84 that detects the relative position of the wafer 40 with respect to the measuring table 82, a shape measuring unit 90 that is provided to be movable in the radial direction of the measuring table 82 and measures the three-dimensional shape of the outer edge 42 of the wafer 40 using a plurality of imaging data captured from the radial outside of the wafer 40 with different focal positions, and a control unit 160 that controls each part of the wafer processing apparatus 10. The control unit 160 adjusts the position of the shape measuring unit 90 in the radial direction based on the relative position.

Description

[Technical Field]

[0001] The present disclosure relates to a wafer processing apparatus that processes an outer peripheral edge of a wafer. [Background Art]

[0002] Wafers are used as materials for semiconductor devices, electronic components, and the like. A wafer is surface-processed by a polishing apparatus. The edge of a surface-processed wafer becomes sharp due to the surface processing, which can cause cracking and chipping. For this reason, wafers are subjected to a grinding process called chamfering to remove sharp edges at the periphery. Patent Document 1 discloses a wafer chamfering apparatus that performs chamfering on a wafer.

[0003] The shape and dimensions of the edge of a wafer formed by grinding are specified by standards established by industry associations or requirements from clients. In the wafer manufacturing process, after grinding, the shape of the edge of the wafer is measured, and shape measurement is performed to inspect whether the shape of the edge is within a specified range. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2009-78326 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] The time required for shape measurement can affect the throughput in wafer manufacturing. Therefore, there is a demand for improving the efficiency of wafer measurement. [Means for Solving the Problem]

[0006] A wafer processing apparatus according to one aspect of the present disclosure is a wafer processing apparatus for chamfering a wafer using a grinding wheel, comprising: a measuring table that holds the wafer and is configured to be rotatable; a first sensor that detects the relative position of the wafer with respect to the measuring table; a shape measuring unit that is provided to be movable in the radial direction of the measuring table and measures the three-dimensional shape of the outer edge of the wafer using a plurality of imaging data obtained by imaging the outer edge of the wafer from the outside in the radial direction with different focal positions; and a control unit that controls each part of the wafer processing apparatus, wherein the control unit adjusts the position of the shape measuring unit in the radial direction based on the relative position. [Effects of the Invention]

[0007] According to this disclosure, the efficiency of wafer measurement can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a plan view showing a schematic configuration of one embodiment of a wafer processing apparatus. [Figure 2] Figure 2 is a block diagram showing the schematic configuration of the wafer processing apparatus shown in Figure 1. [Figure 3] Figure 3 is an explanatory diagram showing the schematic configuration of the processing section in Figure 1. [Figure 4] Figure 4 is a schematic plan view showing the wafer measurement points in the measurement section of Figure 1, as well as the arrangement of the shape measurement section and each sensor. [Figure 5] Figure 5 is an explanatory diagram of wafer detection by the first and second sensors. [Figure 6] Figure 6 is an explanatory diagram of the shape measurement unit and the detection of the wafer by the third sensor. [Figure 7] Figure 7 is a block diagram showing the schematic configuration of the shape measuring unit. [Figure 8] Figure 8 is a block diagram showing the schematic configuration of the optical unit. [Figure 9] Figure 9 is an explanatory diagram of the shape of the outer edge of the wafer. [Figure 10]Figure 10 is an explanatory diagram showing the relationship between the imaging range of the optical unit and the outer edge of the wafer. [Figure 11] Figure 11 is an explanatory diagram of the wafer's appearance as detected by the third sensor. [Figure 12] Figure 12 is an explanatory diagram of the end shape of the Tsurua. [Figure 13] Figure 13 is an explanatory diagram illustrating the measurement of the end shape of the Turua by the shape measuring unit. [Figure 14] Figure 14 is a flowchart showing the wafer processing method. [Modes for carrying out the invention]

[0009] Embodiments and modifications of the wafer processing apparatus 10 of this disclosure will be described below with reference to the attached drawings. The attached drawings are merely illustrative of embodiments of this disclosure and should not be considered as limiting this disclosure. Terms such as “first,” “second,” and “third” in this disclosure are used solely to distinguish between objects and do not rank them.

[0010] (One embodiment) An embodiment of the wafer processing apparatus 10 will be described below with reference to Figures 1 to 14.

[0011] (Overview of wafer processing equipment) Figure 1 is a plan view showing the schematic configuration of the wafer processing apparatus 10. In the following description, of the mutually orthogonal XYZ axes shown in the figure, the X-axis and Y-axis directions represent the horizontal direction, and the Z-axis direction represents the height direction (vertical direction). In the following description, the Z-axis direction may also be considered the height direction.

[0012] As shown in Figure 1, the wafer processing apparatus 10 includes a supply and recovery unit 12, a processing unit 16, a cleaning unit 18, a measuring unit 20 for alignment and measurement, and a transport unit 22. The supply and recovery unit 12 includes a cassette table 32 and a supply and recovery robot 34. A wafer cassette 36 that accommodates wafers 40 is placed on the cassette table 32. The wafer cassette 36 accommodates unprocessed wafers 40.

[0013] The supply and recovery unit 12 supplies unprocessed wafers 40 from the wafer cassette 36 to the measurement unit 20 by means of the supply and recovery robot 34. Further, the supply and recovery unit 12 causes the supply and recovery robot 34 to accommodate processed wafers 40 from the measurement unit 20 into the wafer cassette 36.

[0014] The transfer unit 22 is configured to transfer wafers 40 to the processing unit 16, the cleaning unit 18, and the measurement unit 20. In one example, the transfer unit 22 is configured to transfer wafers 40 to the processing unit 16, the cleaning unit 18, and the measurement unit 20 in the order of the measurement unit 20, the processing unit 16, the cleaning unit 18, and the measurement unit 20. That is, the transfer unit 22 is configured to transfer an unprocessed wafer 40 from the measurement unit 20 to the processing unit 16. Next, the transfer unit 22 is configured to transfer the processed wafer 40 from the processing unit 16 to the cleaning unit 18. Then, the transfer unit 22 is configured to transfer the wafer 40 from the cleaning unit 18 to the measurement unit 20.

[0015] The wafer processing apparatus 10 includes two processing units 16 having the same configuration. In the following description, when distinguishing the two processing units 16 from each other, they are described as a first processing unit 16A and a second processing unit 16B.

[0016] The first processing unit 16A and the second processing unit 16B are arranged in parallel on the front portion of the wafer processing apparatus 10. The first processing section 16A and the second processing section 16B are configured to grind the edges of the wafer 40. In one example, the grinding process includes rough grinding and fine grinding. The first processing section 16A and the second processing section 16B include a wafer feeding device 62 and an outer edge grinding device 66. The outer edge grinding device 66 includes a grinding wheel for grinding the outer edge 42 of the wafer 40. The wafer feeding device 62 is configured to move the held wafer 40 relative to the outer edge grinding device 66.

[0017] The wafer feeding device 62 includes a grinding table 64 that holds the wafer 40. In one example, the transport unit 22 transports the wafer 40 from the measuring unit 20 to the first processing unit 16A and the second processing unit 16B. In one example, the transport unit 22 transports the wafer 40 so that the center of the wafer 40 detected by the measuring unit 20 is aligned with the rotation axis of the grinding table 64 of the processing unit 16. The processing unit 16 grinds the outer peripheral edge 42 of the wafer 40 held on the grinding table 64 using an outer peripheral grinding device 66. Then, the transport unit 22 transports the wafer 40 processed in the first processing unit 16A to the cleaning unit 18, and the wafer 40 processed in the second processing unit 16B to the cleaning unit 18. By providing two processing units 16 in this way, the processing time for one wafer 40 in the grinding process is shortened.

[0018] The cleaning unit 18 is configured to clean the processed wafer 40. In one example, the cleaning unit 18 includes a spin cleaning device. The cleaning unit 18 includes a cleaning table 72, which rotates the wafer 40 held on the cleaning table 72 and sprays cleaning fluid onto the surface of the wafer 40 to remove dirt adhering to the surface of the wafer 40. The wafer 40 cleaned by the cleaning unit 18 is transported to the measuring unit 20.

[0019] The measuring unit 20 measures the wafer 40 before and after processing. The measuring unit 20 is configured to measure the center and thickness of the wafer 40 before processing. The measuring unit 20 is configured to measure the diameter, thickness, edge shape, and edge roughness of the wafer 40 after processing.

[0020] The measurement unit 20 includes a measurement table 82, a first sensor 84, a second sensor 86, a third sensor 88, and a shape measurement unit 90. The measurement table 82 is configured to hold the wafer 40 and to be rotatable. The first sensor 84 is configured to detect the relative position of the wafer 40 with respect to the measurement table 82. The second sensor 86 is configured to detect the height of the outer edge 42 in the height direction intersecting the radial direction. The third sensor 88 is configured to detect the appearance of the outer edge 42. The shape measurement unit 90 is configured to measure the shape of the outer edge 42 of the processed wafer 40.

[0021] (Configuration of the processing section) Figure 2 is a block diagram showing the schematic configuration of the wafer processing apparatus 10. Figure 3 shows the schematic configuration of the processing unit 16.

[0022] As shown in Figure 3, the processing unit 16 includes a wafer feeding device 62 and an outer circumference grinding device 66. The wafer feeding device 62 includes a grinding table 64, a table drive unit 102, and a position control unit 104.

[0023] The grinding table 64 has a holding surface 64A for holding the wafer 40. The grinding table 64 is configured to rotate around a rotation axis G1 parallel to the Z-axis direction. The table drive unit 102 is composed of various actuators such as a motor drive mechanism. The table drive unit 102 rotates the grinding table 64 around the rotation axis G1 under the control of the control unit 160. As a result, the wafer 40 held on the grinding table 64 rotates around the rotation axis G1.

[0024] The position control unit 104 is composed of various actuators such as motor drive mechanisms and moving mechanisms such as linear sliders. The actuators and moving mechanisms are provided corresponding to the X, Y, and Z axes. The position control unit 104 moves the grinding table 64 along each of the X, Y, and Z axes under the control of the control unit 160. As a result, the wafer 40 held on the grinding table 64 moves along each of the X, Y, and Z axes.

[0025] The outer circumference grinding device 66 includes grinding wheels 112 and 114. The outer circumference grinding device 66 includes a grinding wheel drive unit 106. The grinding wheel drive unit 106 rotates the grinding wheels 112 and 114. In one example, grinding wheel 112 rough grinds the outer circumference edge 42 of the wafer 40. In another example, grinding wheel 114 fine grinds the outer circumference edge 42 of the wafer 40. The grinding wheels 112 and 114 have grinding grooves on their outer circumference for grinding the outer circumference edge 42 of the wafer 40. The grinding grooves are formed and shaped by a truing wheel (truing wheel) 300 shown in Figures 11 and 12. The truing wheel 300 deteriorates (wears) due to repeated formation and shaping of the grinding grooves. In one example, grinding wheel 112 has a master groove for shaping the truing wheel 300.

[0026] (Configuration of the measurement unit) Next, the measurement unit 20 will be described in accordance with Figures 4 to 8. The measuring unit 20 measures the processed wafer 40. The measuring unit 20 is configured to measure the diameter of the wafer 40, the thickness of the wafer 40, the shape of the edge of the wafer 40, the roughness of the edge of the wafer 40, and so on.

[0027] As shown in Figures 4 to 7, the measuring unit 20 includes a measuring table 82. The measuring table 82 has a holding surface 82A. In one example, the measuring table 82 adsorbs and holds a wafer 40 placed on the holding surface 82A. The measuring table 82 is configured to be rotatable around its rotation axis G2.

[0028] As shown in Figure 7, the measuring unit 20 includes a table drive unit 122. The table drive unit 122 is composed of various actuators, such as a motor drive mechanism. The table drive unit 122 rotates the measuring table 82 in one direction around the rotation axis G2 under the control of the control unit 160. As a result, the wafer 40 held on the holding surface 82A of the measuring table 82 rotates around the rotation axis G2 of the measuring table 82.

[0029] As shown in Figures 4 and 5, the measurement unit 20 includes a first sensor 84. The first sensor 84 is configured to detect the diameter, reference position, center position, eccentricity, etc., of a wafer 40. In one example, the reference position of the wafer 40 is a notch provided on the wafer 40. The notch is a cutout portion provided on a part of the circumferential edge of the outer edge of the wafer 40. In one example, the first sensor 84 is a laser sensor or a laser alignment sensor. As shown in Figure 5, the first sensor 84 includes an emission unit 84A and a light receiving unit 84B. The emission unit 84A and the light receiving unit 84B are arranged facing each other in the Z-axis direction on the radially outside of the measurement table 82. The emission unit 84A is configured to emit a line-shaped detection light extending in the radial direction of the measurement table. The light receiving unit 84B is configured to receive the detection light. The light-emitting unit 84A and the light-receiving unit 84B are positioned such that a portion of the detected light is blocked by the wafer 40 held on the measurement table 82. The light-receiving unit 84B is configured to detect the position of the outer edge 42 of the wafer 40 by the portion that receives the detected light and the portion that receives the detected light but is blocked by the wafer 40. The measurement result of the first sensor 84 is output to the measurement control unit 162 of the control unit 160 shown in Figure 2. The measurement control unit 162 calculates the center position of the wafer 40, the diameter of the wafer 40, the eccentricity of the wafer 40, the depth of the notch of the wafer 40, etc., based on the measurement result of the first sensor 84.

[0030] As shown in Figures 4 and 5, the measurement unit 20 includes a second sensor 86. The second sensor 86 is configured to detect the thickness of the wafer 40, etc. In one example, the second sensor 86 is a distance sensor. As shown in Figure 5, the second sensor 86 includes a first sensor unit 86A and a second sensor unit 86B. The first sensor unit 86A and the second sensor unit 86B are arranged to sandwich the wafer 40 at a predetermined distance apart in the height direction. The first sensor unit 86A and the second sensor unit 86B are arranged to measure the same position in the XY plane. The first sensor unit 86A measures the distance to the surface (top surface) of the wafer 40. The second sensor unit 86B measures the distance to the surface (bottom surface) of the wafer 40. The measurement results of the first sensor unit 86A and the second sensor unit 86B are output to the measurement control unit 162 shown in Figure 2. The measurement control unit 162 calculates the distance from the first sensor unit 86A and the second sensor unit 86B to the surface of the wafer 40, and the thickness of the wafer 40 and the Trua 300 (see Figure 11), based on the distance between the first sensor unit 86A and the second sensor unit 86B and the measurement results of the first sensor unit 86A and the second sensor unit 86B. Alternatively, the measurement control unit 162 may calculate the thickness of the wafer 40 and the Trua 300 based on the measurement results of the second sensor 86.

[0031] In the measurement unit 20, the first sensor 84 and the second sensor 86 measure the thickness of the wafer 40 before processing and perform pre-alignment. In addition, the measurement unit 20 measures the thickness, center position, and diameter of the wafer 40 after processing using the first sensor 84 and the second sensor 86.

[0032] Furthermore, the second sensor 86 is configured to detect the height position (or warp) of the outer edge 42 of the wafer 40 in the height direction. In one example, the height position of the outer edge 42 is the center position of the wafer 40 in the height direction at the detection position of the second sensor 86. Note that the height position of the outer edge 42 may be the height position of the bottom surface of the wafer 40, the height position of the top surface of the wafer 40, or the height position of another part of the wafer 40. For example, the measurement control unit 162 calculates the height position of the outer edge 42 of the wafer 40 based on the height of the holding surface 82A of the measurement table 82 and the measurement result of the second sensor 86, for example, the thickness of the wafer 40. The second sensor 86 may be a capacitance sensor, a confocal sensor, a spectroscopic interference laser displacement meter, etc.

[0033] As shown in Figures 4 and 6, the measurement unit 20 includes a third sensor 88. The third sensor 88 is configured to detect the appearance of the wafer 40. In one example, the third sensor 88 is a camera that images the appearance of the wafer 40. The camera has a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) type image sensor. As shown in Figure 6, the third sensor 88 includes a first imaging unit 88A and a second imaging unit 88B. The first imaging unit 88A images the top surface of the wafer 40 as the appearance of the wafer 40. The second imaging unit 88B images the bottom surface of the wafer 40 as the appearance of the wafer 40. The third sensor 88 includes an illumination unit (not shown). The illumination unit is configured to irradiate the wafer 40 in the area imaged by the first imaging unit 88A and the second imaging unit 88B with suitable light. The imaging data from the first imaging unit 88A and the second imaging unit 88B are output to the shape and roughness analysis unit 164 shown in Figure 2. The shape and roughness analysis unit 164 analyzes the roughness of the wafer 40 based on the imaging data from the third sensor 88.

[0034] As shown in Figures 4, 6, 7, and 8, the measurement unit 20 includes a shape measurement unit 90. The shape measurement unit 90 is configured to measure the shape of the outer peripheral edge 42 of the wafer 40. As shown in Figure 6, the shape measurement unit 90 is configured to be movable in the radial direction of the measurement table 82. The shape measurement unit 90 is also configured to be movable in the height direction relative to the measurement table 82. The shape measurement unit 90 is configured to measure the shape of the outer peripheral edge 42 of the wafer 40 from the radial outside. Specifically, the shape measurement unit 90 is configured to measure the three-dimensional shape of the outer peripheral edge 42 of the wafer 40 using multiple imaging data obtained by imaging the outer peripheral edge 42 of the wafer 40 from the radial outside with different focal positions.

[0035] Figure 4 shows the measurement locations 220 on wafer 40. The wafer 40 is circular in shape when viewed from the height direction in a plan view. The outer edge 42 of the wafer 40 includes a circular outer portion 42A and a notch portion 42B, which is a cutout portion provided in a part of the wafer 40 in the circumferential direction. The measuring unit 20 sets a plurality of measurement points 220 in the circumferential direction with respect to the center O1 of the wafer 40. In one example, the plurality of measurement points 220 are set with respect to the notch portion 42B as the reference point, and are set at equal angular intervals in the circumferential direction from the notch portion 42B. However, the plurality of measurement points 220 may be set so as not to include the notch portion 42B.

[0036] The measurement unit 20 sets multiple measurement points 220 at predetermined measurement intervals in the circumferential direction. In one example, the measurement interval is the central angle with respect to the center O1 of the wafer 40. Figure 4 shows the state where the center O1 of the wafer 40 coincides with the rotation axis G2 of the measurement table 82. In one example, the measurement unit 20 sets multiple measurement points 220 so that the measurement intervals are equal, that is, so that the central angle θ11 is equal with respect to the center O1 of the wafer 40. In one example, the central angle θ11 is 45 degrees. Note that the central angle θ11 can be changed arbitrarily, for example, 90 degrees. The measurement unit 20 rotates the wafer 40 so as to measure the shape of the wafer 40 at each of the set measurement points 220.

[0037] Figure 4 also shows an example of the arrangement of the first sensor 84, second sensor 86, third sensor 88, and shape measuring unit 90 relative to the measurement table 82 (wafer 40), viewed from the height direction (above).

[0038] As shown in Figure 4, the measurement table 82 rotates in one direction indicated by arrow AR1 by the table drive unit 122 shown in Figure 2. Therefore, the wafer 40 held on the measurement table 82 rotates in one direction indicated by arrow AR1.

[0039] As shown in Figure 4, the first sensor 84, the second sensor 86, the third sensor 88, and the shape measuring unit 90 are arranged along the rotational direction of the measuring table 82. The first sensor 84, the third sensor 88, and the second sensor 86 are arranged in the rotational direction in the order described. In one example, the shape measuring unit 90 is located between the second sensor 86 and the first sensor 84.

[0040] The shape measuring unit 90 and the third sensor 88 are positioned at a distance of an integer multiple of the measurement interval in the circumferential direction of the measuring table 82 with respect to the rotation axis G2, which is the center of the measuring table 82. In one example, the shape measuring unit 90 and the third sensor 88 are positioned at a distance of twice the central angle θ11, which is the measurement interval. In other words, with respect to the rotation axis G2 of the measuring table 82, the shape measuring unit 90 and the third sensor 88 are positioned so that the central angle θ12 is 90 degrees. Therefore, when one measurement point 220 on the wafer 40, for example measurement point 220A, is positioned relative to the third sensor 88, another measurement point 220B on the wafer 40 is positioned relative to the shape measuring unit 90.

[0041] Furthermore, the third sensor 88 and the shape measuring unit 90 are arranged in the rotational direction in the order described above. Therefore, for each measurement point 220 of the wafer 40, the external appearance is detected by the third sensor 88, and then the three-dimensional shape is measured by the shape measuring unit 90.

[0042] The first sensor 84 and the third sensor 88 are positioned on a straight line passing through the rotation axis G2 of the measurement table 82, with the measurement table 82 in between, when viewed from the height direction (above). In other words, the first sensor 84 and the third sensor 88 are positioned at a central angle of 180 degrees with respect to the rotation axis G2 of the measurement table 82.

[0043] In one example, the second sensor 86 is positioned between the third sensor 88 and the shape measuring unit 90 in the rotational direction of the measurement table 82. In another example, the third sensor 88 is positioned midway between the third sensor 88 and the shape measuring unit 90 in the rotational direction of the measurement table 82. In other words, the second sensor 86 is positioned at a central angle of 45 degrees with respect to the rotation axis G2 of the measurement table 82.

[0044] The second sensor 86 detects the thickness of the wafer 40. In one example, the second sensor 86 is positioned to detect the thickness of the wafer 40 in the area inside the outer edge 42, but closer to the outer edge 42.

[0045] The second sensor 86 and the shape measuring unit 90 are positioned between the third sensor 88 and the first sensor 84 in the rotational direction of the measurement table 82, that is, in the rotational direction of the wafer 40. In other words, no sensors are positioned between the first sensor 84 and the third sensor 88 in the rotational direction of the measurement table 82. That is, the first sensor 84, second sensor 86, third sensor 88, and shape measuring unit 90 of the measurement unit 20 are positioned biased toward the side of the measurement table 82 where the shape measuring unit 90 is located, in the Y-axis direction. As shown in Figure 1, the shape measuring unit 90 is positioned on the opposite side of the measurement table 82 from the transport unit 22.

[0046] (Configuration of the shape measurement unit) The configuration of the shape measuring unit 90 will now be described. Figure 7 shows the schematic configuration of the shape measuring unit 90.

[0047] The shape measuring unit 90 includes an optical unit 132, an optical unit drive unit 134, and a control unit 160. As shown in Figure 2, the control unit 160 includes a measurement control unit 162 and a shape / roughness analysis unit 164 as functional blocks related to the shape measuring unit 90.

[0048] In one example, the optical unit 132 is comprised of a white light interference microscope. The optical unit 132 is positioned radially adjacent to the measurement table 82. Specifically, the optical unit 132 is positioned such that its optical axis LA is parallel (including approximately parallel) to the holding surface 82A of the measurement table 82. The optical unit 132 is positioned such that its optical axis LA is parallel (including approximately parallel) to the direction perpendicular to the rotation axis G2 of the measurement table 82. The optical unit 132 then images the outer edge 42 of the wafer 40 held on the measurement table 82 from a position facing the outer edge 42 of the wafer 40 in the radial direction of the wafer 40.

[0049] Next, the configuration of the optical unit 132 will be described. Figure 8 shows the configuration of the optical unit 132. The optical unit 132 is a white light interference microscope. The optical unit 132 includes a light source unit 136, a beam splitter 138, an interference objective lens 140, an imaging lens 142, and a camera 144. The beam splitter 138, interference objective lens 140, imaging lens 142, and camera 144 are arranged on the optical axis LA of the interference objective lens 140. The interference objective lens 140, beam splitter 138, imaging lens 142, and camera 144 are arranged in this order from the surface to be measured at the outer edge 42 of the wafer 40 which is the object to be measured. The light source unit 136 is positioned in a direction intersecting the optical axis LA of the interference objective lens 140, such that the measurement light L1 emitted from the light source unit 136 is incident on the beam splitter 138.

[0050] The light source unit 136 emits measurement light L1, which is white light in a parallel beam, under the control of the control unit 160. White light is low-coherence light with low coherence. The light source unit 136 includes a light source such as a light-emitting diode, semiconductor laser, halogen lamp, and high-intensity discharge lamp, and a collector lens that converts the measurement light L1 emitted from the light source into a parallel beam.

[0051] In one example, the beam splitter 138 is a half-mirror. The beam splitter 138 reflects a portion of the measurement light L1 incident from the light source 136 toward the interference objective lens 140. The beam splitter 138 also transmits a portion of the combined light L4, described later, incident from the interference objective lens 140.

[0052] The interference objective lens 140 is, in one example, a Michelson-type interference optical system. Therefore, the optical unit 132 of this embodiment can be described as a Michelson-type white-light interference microscope. However, the interference optical system is not limited to the Michelson type; known interference optical systems such as the Mirau type or Linik type can also be used.

[0053] The interference objective lens 140 includes an objective lens 146, a beam splitter 148, and a reference mirror 150. The objective lens 146 and the beam splitter 148 are positioned on the optical axis LA of the interference objective lens 140. The objective lens 146 and the beam splitter 148 are positioned in this order toward the surface to be measured at the outer edge 42 of the wafer 40 which is the object to be measured.

[0054] The reference mirror 150 is positioned in a direction intersecting the optical axis LA of the interference objective lens 140, and is where the reference light L2 is incident. In one example, the reference mirror 150 is a reflective mirror and has a reference surface 150A that reflects light. The reference mirror 150 is positioned so that the reference light L2 is incident on the reference surface 150A. It can be said that the reference mirror 150 is positioned so that the reference surface 150A faces the beam splitter 148. The distance between the beam splitter 148 and the reference surface 150A of the reference mirror 150 can be adjusted by an adjustment mechanism (not shown). The adjustment mechanism consists of a ball screw mechanism, an actuator, etc. This allows the optical path length of the reference light L2, i.e., the reference optical path length, to be adjusted.

[0055] The objective lens 146 has a light-gathering function. The objective lens 146 focuses the incident measurement light L1 onto the surface to be measured through the beam splitter 148. The beam splitter 148 splits a portion of the incident measurement light L1 into a reference light L2. In one example, the beam splitter 148 is a half-mirror. The beam splitter 148 reflects a portion of the incident measurement light L1 as reference light L2 in a direction intersecting the optical axis LA, and transmits the remaining measurement light L3. The measurement light L3 that has passed through the beam splitter 148 is irradiated onto the surface to be measured. The measurement light L3 is reflected from the surface to be measured and incident on the beam splitter 148.

[0056] The reference light L2 reflected by the beam splitter 148 is reflected by the reference plane 150A and incident on the beam splitter 148. The beam splitter 148 transmits a portion of the measurement light L3 reflected from the outer edge 42 of the wafer 40, which is the surface to be measured, and reflects a portion of the reference light L2 reflected from the reference surface 150A. This generates a combined light L4 of the measurement light L3 and the reference light L2. This combined light L4 can be described as interference light of the measurement light L3 and the reference light L2. The combined light L4 passes through the objective lens 146 and the beam splitter 138 and enters the imaging lens 142.

[0057] The imaging lens 142 forms an image of the incident multiplexed light L4 on the imaging surface of the camera 144. Specifically, the imaging lens 142 forms an image of a point on the focal plane of the objective lens 146 as an image point on the imaging surface of the camera 144.

[0058] Camera 144 includes a CCD or CMOS type image sensor. Camera 144 captures the multiplexed light L4 imaged on the image sensor's imaging surface by an imaging lens 142, and outputs an image signal by signal processing of the image signal of the multiplexed light L4 obtained by this capture. Camera 144 is an example of an imaging unit.

[0059] Figure 10 shows the relationship between the imaging range 420 of the optical unit 132 and the outer edge 42 of the wafer 40. The imaging range 420 is shown by a dotted line. The imaging range 420 of the optical unit 132 is set to correspond to the thickness T1 of the wafer 40. In one example, the imaging range 420 of the optical unit 132 is set by the magnification of the interference objective lens 140 shown in Figure 8 and the size of the image sensor of the camera 144 (size of the imaging surface, number of photodetectors). In one example, the imaging range 420 of the optical unit 132 is set so that imaging data of the entire outer edge 42 of the wafer 40 can be obtained in one shot in the height direction. If the imaging range 420 in the height direction is too large compared to the thickness T1 of the wafer 40, the measurement accuracy of the three-dimensional shape obtained from the imaging data will be low. On the other hand, if the imaging range 420 in the height direction is smaller than the thickness T1 of the wafer 40, more detailed imaging data can be obtained, but the position of the optical unit 132 must be changed in the height direction for each measurement point 220, which takes time.

[0060] The optical unit drive unit 134 is composed of various actuators such as a linear motor or a motor drive mechanism. The optical unit drive unit 134 holds the optical unit 132 so as to be movable in the Y-axis direction, which is the scanning direction. This makes it possible to adjust the relative position of the optical unit 132 in the radial direction (Y-axis direction) of the measurement table 82 with respect to the outer edge 42 of the wafer 40 which is the object to be measured. Then, under the control of the control unit 160, the optical unit drive unit 134 scans the optical unit 132 in the Y-axis direction, that is, in a direction parallel to the optical axis LA of the optical unit 132. The optical unit drive unit 134 is an example of a relative movement unit.

[0061] Furthermore, the optical unit drive unit 134 holds the optical unit 132 so that it can move not only in the Y-axis direction but also in the Z-axis direction, which is the height direction. The optical unit drive unit 134 may also hold the optical unit 132 so that it can move not only in the Y-axis and Z-axis directions but also in the X-axis direction. This makes it possible to adjust the relative position of the optical unit 132 in the height direction with respect to the outer edge 42 of the wafer 40 which is the object to be measured. In addition, it is possible to take multiple images while moving the optical unit 132 in the Z-axis direction or the X-axis direction. This makes it possible to image a wider range than the limitations of the measurement field of view of the interference objective lens 140.

[0062] The scale 152 is a position detection sensor that detects the position of the optical unit 132 in the Y-axis direction. The scale 152 is, for example, a linear scale. This scale 152 repeatedly detects the position of the optical unit 132 in the Y-axis direction and repeatedly outputs the position detection result to the control unit 160.

[0063] [Functions of wafer processing equipment] Figure 2 is a functional block diagram of the control unit 160 in the wafer processing apparatus 10. Note that Figure 2 shows the portion of the control unit 160 related to the processing unit 16 and the measurement unit 20 in the wafer processing apparatus 10. In the following description, functional blocks will sometimes be explicitly described, and sometimes multiple functional blocks will be collectively referred to as the control unit 160.

[0064] The control unit 160 includes a machining control unit 168 for controlling the machining unit 16. The machining control unit 168 is connected to the table drive unit 102, the position control unit 104, and the grinding wheel drive unit 106 of the machining unit 16.

[0065] The control unit 160 includes a measurement control unit 162 for controlling each part of the measurement unit 20, and a shape / roughness analysis unit 164 for obtaining measurement results of the object to be measured. The measurement control unit 162 is connected to a table drive unit 122, a first sensor 84, a second sensor 86, a third sensor 88, an optical unit drive unit 134, an optical unit 132, and a scale 152. The shape / roughness analysis unit 164 is connected to the camera 144 of the optical unit 132 and the third sensor 88.

[0066] Furthermore, the control unit 160 includes a feedback calculation unit 166 for providing feedback to the processing unit 16 based on the measurement results from the measurement unit 20. Furthermore, the control unit 160 is connected to an operation unit 172 and an output unit 174. The operation unit 172 includes an input device for receiving operator input to the control unit 160. The input device may be, for example, a touch panel, keyboard, mouse, etc. Non-contact devices such as sensors may also be used as input devices. The output unit 174 is a device for outputting data such as the execution results of a program and calculation results by the control unit 160. The output unit 174 includes, for example, an operation UI (User Interface) and a monitor (for example, a liquid crystal display, etc.) for displaying detection results. In addition to the monitor, or instead of the monitor, the output unit 174 may also include a printer or speaker, etc. The operation unit 172 and the output unit 174 may be composed of a personal computer or a portable terminal such as a tablet. Furthermore, in addition to the operation unit 172 and the output unit 174, a portable terminal may also be connected to the control unit 160.

[0067] The control unit 160 performs processing and measurement processing on the wafer 40 by the wafer processing apparatus 10 in response to the operation input from the operation unit 172. The control unit 160 includes a processor that performs various processes (e.g., a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc.), memory that serves as the processor's workspace (e.g., ROM (Read Only Memory) and RAM (Random Access Memory), etc.), and a storage device for saving various programs and data (e.g., an SSD (Solid State Drive) or an HDD (Hard Disk Drive), etc.).

[0068] The control unit 160 functions as a measurement control unit 162, a shape / roughness analysis unit 164, a feedback calculation unit 166, and a machining control unit 168 by executing a program stored on a storage device using a processor.

[0069] The machining control unit 168 controls the table drive unit 122, the position control unit 104, and the grinding wheel drive unit 106 to perform grinding on the wafer 40, that is, chamfering the outer edge 42 of the wafer 40. The machining control unit 168 also controls the table drive unit 122, the position control unit 104, and the grinding wheel drive unit 106 to perform maintenance on the grinding wheels 112 and 114 shown in Figure 3. The machining control unit 168 also controls the table drive unit 122, the position control unit 104, and the grinding wheel drive unit 106 to perform maintenance on the Tulua 300 shown in Figures 12 and 13.

[0070] The measurement control unit 162 controls the table drive unit 122, the first sensor 84, and the second sensor 86 to detect the relative position of the outer edge 42 of the wafer 40 held on the measurement table 82, as well as the diameter, thickness, and height of the wafer 40. Based on the detection results, the measurement control unit 162 sets up a plurality of measurement points 220. The plurality of measurement points 220 are set at predetermined measurement intervals in the circumferential direction of the wafer 40, which is the object to be measured.

[0071] The measurement control unit 162 controls the table drive unit 122 to rotate the wafer 40 held on the measurement table 82 at measurement intervals. This rotational movement positions the multiple measurement points 220 on the wafer 40 at positions corresponding to the third sensor 88 and the shape measurement unit 90, respectively, with each rotation. Specifically, the multiple measurement points 220 on the wafer 40 are positioned at positions where the appearance can be detected by the third sensor 88 with each rotation. Similarly, the multiple measurement points 220 on the wafer 40 are positioned at positions where the three-dimensional shape can be measured by the shape measurement unit 90 with each rotation. Therefore, it is possible to simultaneously perform appearance detection of the wafer 40 by the third sensor 88 and measurement of the three-dimensional shape of the outer edge 42 of the wafer 40 by the shape measurement unit 90.

[0072] [Visual inspection using a third sensor] The measurement control unit 162 controls the table drive unit 122 and the third sensor 88 to detect the appearance of the outer edge 42 of the wafer 40. Specifically, the measurement control unit 162 controls the table drive unit 122 to rotate the measurement table 82 so that the measurement point 220 of the wafer 40 is in a position corresponding to the third sensor 88. In one example, the measurement control unit 162 rotates the wafer 40 so that the measurement point 220 of the wafer 40 is located on a straight line passing through the center of the imaging range of the third sensor 88 and the rotation axis G2 of the measurement table 82. The measurement control unit 162 controls the table drive unit 122 and the third sensor 88 to obtain imaging data of the outer edge 42 of the wafer 40 from the upper surface 201 side of the wafer 40 and imaging data of the outer edge 42 from the lower surface 202 side of the wafer 40.

[0073] Figure 4 shows the imaging ranges 402 and 404 by the third sensor 88 as dotted rectangles. The imaging range 402 at measurement point 220A and the imaging range 404 at measurement point 220C, which is located a distance equal to the measurement interval in the rotational direction of the wafer 40 from measurement point 220, overlap in part. In other words, the imaging range of the third sensor 88 is configured so that a portion of the imaging range overlaps before and after the wafer 40 is rotated by the measurement table 82. With this imaging range setting, the third sensor 88 can obtain imaging data that captures the entire outer edge 42 of the wafer 40 in the circumferential direction.

[0074] The shape and roughness analysis unit 164 shown in Figure 2 detects the presence or absence of defects such as cracks and chipping on the outer edge 42 of the wafer 40 using imaging data obtained by the third sensor 88. Figure 11 shows imaging data 410 of a wafer 40 in which a defective area 412 has occurred. In one example, a defective area 412 on the wafer 40 can be detected as a region with a different brightness from the rest of the wafer. The shape and roughness analysis unit 164 shown in Figure 2 detects the number of defective areas 412 on the wafer 40. The shape and roughness analysis unit 164 also calculates the area of ​​the defective areas 412 on the wafer 40. The control unit 160 stores the presence, number, and area of ​​the defective areas 412 detected by the shape and roughness analysis unit 164 in a storage device for each wafer 40. The control unit 160 also outputs the presence, number, and area of ​​the defective areas 412 to the output unit 174.

[0075] [Measurement by shape measuring unit] The shape measuring unit 90 controls the table drive unit 122, the optical unit drive unit 134, the light source unit 136, and the camera 144 to measure the three-dimensional shape of the outer edge 42 of the wafer 40 using multiple imaging data obtained by imaging the outer edge 42 of the wafer 40 from the radially outer side with different focal positions.

[0076] More specifically, the measurement control unit 162 of the shape measurement unit 90 controls the table drive unit 122 to sequentially bring each measurement point 220 of the wafer 40 into contact with the optical unit 132. The measurement control unit 162 then controls the optical unit drive unit 134, the light source unit 136, and the camera 144 to scan the optical unit 132 in the radial direction (Y-axis direction) of the wafer 40, while repeatedly imaging the surface of the object to be measured, i.e., the outer edge 42 of the wafer 40, with the camera 144 at regular intervals. This results in obtaining multiple image data with the focal position of the optical unit 132 changed at regular intervals.

[0077] Specifically, the measurement control unit 162 controls the table drive unit 122 to rotate the measurement table 82 so that the measurement point 220 on the wafer 40 is positioned opposite the optical unit 132. After the measurement control unit 162 starts emitting measurement light L1 from the light source unit 136, it controls the optical unit drive unit 134 to scan the optical unit 132 radially across the wafer 40. Based on the detection result of the Y-axis position of the optical unit 132 by the scale 152, the measurement control unit 162 repeatedly performs imaging of multiplexed light L4 by the camera 144 and outputs the imaging data to the control unit 160 each time the optical unit 132 moves by a certain pitch in the Y-axis direction.

[0078] The shape and roughness analysis unit 164 acquires imaging data output from the camera 144 each time the camera 144 captures multiplexed light L4, and generates three-dimensional shape data of the outer edge 42 of the wafer 40. The shape and roughness analysis unit 164 measures the three-dimensional shape of the outer edge 42 of the wafer 40 at the measurement location 220 using the three-dimensional shape data.

[0079] Figure 9 shows the cross-sectional shape of the outer edge 42 of the wafer 40 and an example of the measurement results of the outer edge 42. The wafer 40 has an upper surface 201 and a lower surface 202 opposite to the upper surface 201. The outer peripheral edge 42 of the wafer 40 has an end surface 203 that is substantially perpendicular to the upper surface 201 and the lower surface 202, an upward sloping surface 204 extending from the upper surface 201 to the end surface 203, and a downward sloping surface 205 extending from the lower surface 202 to the end surface 203. The wafer 40 also has an upper curved surface 206 between the upper curved surface 204 and the end surface 203, and a lower curved surface 207 between the downward sloping surface 205 and the end surface 203.

[0080] The shape and roughness analysis unit 164 shown in Figure 2 uses the three-dimensional shape data obtained by the shape measurement unit 90 to determine the upper intersection point 211 between the extension line of the upper inclined surface 204 and the extension line of the end face 203, and the lower intersection point 212 between the extension line of the lower inclined surface 205 and the extension line of the end face 203. The shape and roughness analysis unit 164 then calculates the distance between the upper intersection point 211 and the upper surface 201 as the height dimension X1 of the upper inclined surface 204, the distance between the upper intersection point 211 and the lower intersection point 212 as the length dimension X3 of the end face 203, and the distance between the lower intersection point 212 and the lower surface 202 as the height dimension X2 of the lower inclined surface 205. The shape and roughness analysis unit 164 calculates the width dimension A1 of the upper inclined surface 204 as the distance from the upper intersection 211 to the upper surface 201 in the radial direction (Y-axis direction), and the width dimension A2 of the lower inclined surface 205 as the distance from the lower intersection 212 to the lower surface 202. The width dimensions A1 and A2 may also be determined from the imaging data obtained by the third sensor 88 (see Figure 11). The shape and roughness analysis unit 164 calculates the inclination angle θ1 of the upper inclined surface 204 with respect to the upper surface 201, and the inclination angle θ2 of the lower inclined surface 205 with respect to the lower surface 202. The shape and roughness analysis unit 164 also calculates the radius R1 of the upper curved surface 206 and the radius R2 of the lower curved surface 207.

[0081] The measurement control unit 162 shown in Figure 2 obtains the thickness T1 of the wafer 40 based on the detection result of the second sensor 86. The control unit 160 stores the measurement results of the outer edge 42 detected by the shape and roughness analysis unit 164, the detection results of the measurement control unit 162, etc., in a storage device for each wafer 40. The control unit 160 also outputs the measurement results of the outer edge 42, the detection results of the measurement control unit 162, etc., to the output unit 174.

[0082] The control unit 160 performs a first step of detecting the wafer 40 using the first sensor 84 and the second sensor 86, and a second step of detecting the wafer 40 using the third sensor 88 and the shape measuring unit 90. In the first step, the control unit 160 uses the first sensor 84 and the second sensor 86 to obtain the thickness of the wafer 40, the relative position of the outer edge 42 of the wafer 40 in the radial direction, and the height of the outer edge 40 of the wafer 40 in the height direction. In the second step, the control unit 160 uses the third sensor 88 to detect the appearance of the outer edge 42 of the wafer 40 and uses the shape measuring unit 90 to measure the three-dimensional shape of the outer edge 42 of the wafer 40.

[0083] In the second step, the control unit 160 adjusts the position of the shape measuring unit 90 in the radial direction based on the relative position of the wafer 40 with respect to the measuring table 82. More specifically, the control unit 160 adjusts the position of the optical unit 132 with respect to the outer peripheral edge 42 of the wafer 40 in the radial direction based on the relative position of the wafer 40 with respect to the measuring table 82.

[0084] As described above, the shape measuring unit 90 obtains multiple imaging data each time the optical unit 132, which includes an interference optical system, changes the focal position relative to the surface of the outer edge 42 of the wafer 40 by a certain pitch in the radial direction of the wafer 40. For this reason, the optical unit 132 has a shallow depth of field and a short focal length.

[0085] When a wafer 40 is transported to the measurement table 82 by the transport unit 22, the center of the wafer 40 may not coincide with the rotation axis G2 of the measurement table 82. In this case, the distance between the outer edge 42 of the wafer 40 and the measurement table 82 in the radial direction of the measurement table 82 changes due to the rotational movement of the measurement table 82 and the wafer 40. For this reason, before rotating the wafer 40, it is necessary to move the optical unit 132 away from the measurement table 82 to a position where it does not interfere with the wafer 40. The time required for such movement of the optical unit 132 increases the time required to measure one wafer 40 and affects the throughput of the wafer processing apparatus 10.

[0086] Furthermore, when the shape measuring unit 90 starts measuring a single measurement point 220, it is necessary to move the optical unit 132 to a position where the wafer 40 can be imaged. One possible method for moving the optical unit 132 is to utilize the image data of the measurement point 220 obtained by the optical unit 132. However, this method takes time to acquire the image data and to determine whether or not the surface of the outer edge 42 of the wafer 40 is being imaged, so the movement speed of the optical unit 132 must be slowed down. For this reason, the method of using image data requires a lot of time to move the optical unit 132 to a position where the wafer 40 can be imaged. Moreover, the movement of the optical unit 132 using image data is necessary for each measurement point 220 of the wafer 40. As a result, the method of using image data takes a long time to measure a single wafer 40.

[0087] In contrast, the control unit 160 (shape measuring unit 90) of this embodiment adjusts the position of the optical unit 132 in the radial direction based on the relative position of the outer peripheral edge 42 of the wafer 40 with respect to the measurement table 82, which is obtained by the first sensor 84. This allows the movement speed of the optical unit 132 to be increased. Furthermore, the optical unit 132 can be easily moved to a position where the wafer 40 can be imaged. Consequently, the time required to move the optical unit 132 to a position where the wafer 40 can be imaged is shortened. In this way, the wafer processing apparatus 10 of this embodiment can improve the efficiency of wafer 40 measurement. This shortens the time required to measure one wafer 40 and improves the throughput of the wafer processing apparatus 10.

[0088] Furthermore, in this embodiment, the control unit 160 adjusts the position of the optical unit 132 in the radial direction based on the relative position of the outer peripheral edge 42 at the measurement point 220 while the table drive unit 122 rotates the measurement table 82 and the wafer 40. In other words, there is a period in which the rotation of the measurement table 82 and the adjustment of the position of the optical unit 132 in the radial direction are performed in parallel. Therefore, the time required to start measurement is shortened compared to the case where the relative position of the optical unit 132 is adjusted after the measurement point 220 is facing the optical unit 132. In this way, the wafer processing apparatus 10 of this embodiment can improve the efficiency of wafer 40 measurement. And the time required to measure one wafer 40 can be shortened, improving the throughput of the wafer processing apparatus 10.

[0089] The outer edge 42 of the wafer 40 may move in the height direction due to warping or undulation of the wafer 40. Furthermore, the height position of the outer edge 42 of the wafer 40 may differ in the circumferential direction of the wafer 40 due to warping or undulation. In such cases, a portion of the wafer 40 may fall outside the imaging range of the optical unit 132 in the height direction, making measurement impossible or requiring adjustment of the height position of the optical unit 132 after measurement has started. This can increase the time required for wafer measurement.

[0090] In this embodiment, the control unit 160 adjusts the position of the optical unit 132 in the height direction based on the height position of the wafer 40 obtained by the second sensor 86, specifically the height position of the outer edge 42 at the measurement point 220. This prevents the outer edge 42 of the wafer 40 from going outside the imaging range of the optical unit 132. Furthermore, the height position of the optical unit 132 does not need to be adjusted after measurement of the outer edge 42 has started. As a result, the time required for measuring the wafer 40 can be shortened, that is, the efficiency of measuring the wafer 40 can be improved. And the throughput of the wafer processing apparatus 10 can be improved.

[0091] Furthermore, in this embodiment, the control unit 160 adjusts the position of the optical unit 132 based on the height position of the outer edge 42 at the measurement location 220 while the table drive unit 122 rotates the measurement table 82 and the wafer 40. In other words, there is a period in which the rotation of the measurement table 82 and the adjustment of the position of the optical unit 132 in the height direction are performed in parallel. The height position of the optical unit 132 is adjusted so that the outer edge 42 of the wafer 40 is within the imaging range of the optical unit 132 in the height direction. Therefore, the time required to start measurement is shortened compared to when the height position of the optical unit 132 is adjusted after the measurement location 220 is facing the optical unit 132. As a result, the time required to measure one wafer 40 can be shortened, that is, the efficiency of wafer 40 measurement can be improved. And the throughput of the wafer processing apparatus 10 can be improved.

[0092] [Turua's Measurement and Feedback] During the grinding process, defects may occur in the shape of the outer edge 42 of the wafer 40. These defects include deviations from the processing target in the shape of the outer edge 42, and the occurrence of cracks and chipping on the outer edge 42. The grinding wheels 112 and 114 used in the grinding process are shaped by grinding them with the Tulua 300 to achieve the shape required for the outer edge 42 of the wafer 40. The Tulua 300 deteriorates (wears down) with repeated use. When the Tulua 300 deteriorates, it becomes impossible to adequately shape the grinding wheels 112 and 114, which can lead to defects in the outer edge 42 of the wafer 40. Therefore, shaping of the grinding wheels 112 and 114, and shaping / replacement of the Tulua 300 become necessary.

[0093] The shape and roughness analysis unit 164 generates three-dimensional shape data of the outer peripheral end 302 of the Tsurua 300 by using the Tsurua 300, which is placed on the measurement table 82 of the measurement unit 20, as the object to be measured.

[0094] Figure 12 shows the cross-sectional shape of the outer peripheral end 302 of the Tulua 300. The Tulua 300, like the wafer 40, has an upper surface 311, a lower surface 312, an end surface 313, an upper inclined surface 314, a lower inclined surface 315, an upper curved surface 316, and a lower curved surface 317. The shape and roughness analysis unit 164 sets the upper intersection 321 and the lower intersection 322, and calculates the length dimension X3 of the end surface 313, the height dimension X1 of the upper inclined surface 314, the height dimension X2 of the lower inclined surface 315, the inclination angle θ1 of the upper inclined surface 314, the inclination angle θ2 of the lower inclined surface 315, the radius R1 of the upper curved surface 316, and the radius R2 of the lower curved surface 317.

[0095] As shown in Figure 13, the thickness T2 of the Tsurua 300 is greater than the thickness T1 of the wafer 40. Therefore, the outer edge 302 of the Tsurua 300 is larger than the imaging range 420 of the optical unit 132, which is shown by the dotted line in Figure 13. For this reason, the measurement control unit 162 and the optical unit drive unit 134 adjust the relative position of the optical unit 132 in the height direction (Z-axis direction) with respect to the outer edge 302 of the Tsurua 300, which is the object to be measured. As shown in Figure 13, by moving the optical unit 132 upward from the center of the Tsurua 300, it becomes possible to image the entire upper inclined surface 314 of the Tsurua 300. Also, by moving the optical unit 132 downward from the center of the Tsurua 300, it becomes possible to image the entire lower inclined surface 315 of the Tsurua 300. In this way, by adjusting the relative position of the optical unit 132 with respect to the trua 300 in the height direction, it becomes possible to generate three-dimensional shape data of the outer peripheral end 302 of the trua 300, which has a thickness T2 greater than the imaging range 420 of the optical unit 132.

[0096] The feedback calculation unit 166 performs feedback control according to the measurement results from the shape and roughness analysis unit 164. Traditionally, detecting the deterioration of a tuller (measuring the degree of wear) required external measurement using a separate device from the wafer grinding section, making the tuller deterioration detection process cumbersome. To avoid this complexity, a quantity-based management system was implemented where tullers were replaced when a predetermined number of grinding wheels were used. However, when tullers are replaced uniformly based on quantity management, regardless of their actual deterioration, tullers that are not deteriorated may be replaced.

[0097] Therefore, the wafer processing apparatus 10 of this embodiment periodically measures the Trua 300. For example, at regular intervals from the start of operation of the wafer processing apparatus 10, and each time the number of times the grinding wheels 112 and 114 have been processed using the Trua 300 reaches a predetermined number, the Trua 300 is transported to the measurement unit 20 and the shape of the edge of the Trua 300 is measured.

[0098] The shape and roughness analysis unit 164 generates three-dimensional shape data of the outer peripheral end 302 of the Tulua 300 and calculates the amount of wear. The feedback calculation unit 166, in accordance with the measurement results from the shape and roughness analysis unit 164, outputs (e.g., displays) to the output unit 174 that the Tulua 300 needs to be replaced, or stops the processing of the wafer 40, if the amount of wear exceeds a threshold (e.g., 5 μm). The threshold is not limited to the above; for example, the Tulua 300 may be judged as defective (NG) if the ratio of the degree of wear to the thickness T1 of the wafer 40 is greater than or equal to the threshold (e.g., 1%).

[0099] According to the wafer processing apparatus 10 of this embodiment, by periodically measuring the Trua 300, the degree of wear of the Trua 300 can be parameterized and numerically evaluated. This reduces wasted maintenance costs for the Trua 300 and prevents the replacement of Trua 300 that are not deteriorated. Furthermore, according to the wafer processing apparatus 10 of this embodiment, the probability of processing defects in the wafer 40 can be reduced, thereby improving the reliability of the processing.

[0100] If the measurement result of the wafer 40 shape is unsatisfactory (NG), it is necessary to promptly investigate the cause and restore the system. If the wafer 40 shape is unsatisfactory, the following measures can be considered, for example: Grind the grinding wheels 112 and 114 with the Tulua 300, then grind the wafer 40 again and measure the wafer 40. If the result of the second measurement is also unsatisfactory, replace the Tulua 300 or take other appropriate measures.

[0101] However, with the above approach, if there is a defect in the Tulua 300, the process from grinding wheel maintenance to re-evaluation becomes wasted. In addition, wafer 40 that fails the re-evaluation is also wasted.

[0102] Therefore, in the wafer processing apparatus 10 of this embodiment, if the shape of the wafer 40 is unacceptable, the Trua 300 is measured. This eliminates the need for grinding wheel maintenance and the waste of wafers 40.

[0103] Figure 14 is a flowchart showing a wafer processing method related to the wafer processing apparatus 10 of the embodiment. As shown in Figure 14, in the wafer processing apparatus 10 of this embodiment, first, the shape of the edge of the wafer 40 is measured by the shape measuring unit 90 (step S10). If the measurement result of the wafer 40 is NG, the truing wheel 300 used for maintenance (truing) of the grinding wheels 112 and 114 that ground the wafer 40 is transported to the measuring unit 20, and the shape of the outer edge 302 of the truing wheel 300 is measured by the shape measuring unit 90 (step S12).

[0104] Next, if the shape of the outer peripheral end 302 of the truing tool 300 is good (OK), the truing tool 300 is used to maintain the grinding wheels 112 and 114 (step S14). On the other hand, if the shape of the end of the truing tool 300 is poor (NG), the truing tool 300 is maintained (step S16). For example, the feedback calculation unit 166 notifies the operator via the output unit 174 (e.g., a display prompting replacement of the truing tool 300) to prevent truing from being performed.

[0105] According to the wafer processing apparatus 10 of this embodiment, the steps of truing and re-measurement of the wafer 40 can be omitted, making it possible to identify the cause of defects in the shape of the wafer 40 at an early stage. Furthermore, according to the wafer processing apparatus 10 of this embodiment, since truing is not performed with a defective truing tool 300, no damage occurs to the grinding wheels 112 and 114. Therefore, the running costs of the wafer processing apparatus 10 can be reduced.

[0106] (Effects and Effects of the Embodiment) The operation and effects of this embodiment will now be described. (1) The shape measuring unit 90 is configured to be movable in the radial direction of the measuring table 82, and measures the three-dimensional shape of the outer edge 42 of the wafer 40 held on the measuring table 82 by imaging data obtained from the radial outside with different focal positions. The first sensor 84 detects the relative position of the wafer 40 with respect to the measuring table 82. The control unit 160 adjusts the position of the shape measuring unit in the radial direction based on the relative position. In the wafer processing apparatus 10 of this embodiment, the time required to move the optical unit 132 to a position where the wafer 40 can be imaged is short. In this way, the wafer processing apparatus 10 of this embodiment can improve the efficiency of wafer measurement.

[0107] (2) The second sensor 86 detects the height position of the outer edge in the height direction. The shape measuring unit 90 is provided to be movable in the height direction, and the control unit 160 adjusts the position of the shape measuring unit 90 in the height direction based on the height position. The height position of the optical unit 132 can be adjusted so that the outer edge 42 moves in the height direction due to warping or undulation in the wafer 40, so that the outer edge 42 is within the imaging range of the optical unit 132. Therefore, compared to the case in which the height position of the optical unit 132 is adjusted after the measurement point 220 is positioned opposite the optical unit 132, the time required to start measurement is shortened, and the efficiency of measurement can be improved.

[0108] (3) The third sensor 88 detects the appearance of the outer edge 42. The third sensor 88 and the shape measuring unit 90 are positioned at a distance of an integer multiple of the measurement interval measured by the shape measuring unit 90 in the rotational direction of the measuring table 82 around the rotation axis G2. Therefore, when one measurement point 220 of the wafer 40 is positioned relative to the shape measuring unit 90, for example, measurement point 220, other measurement points 220 of the wafer 40 are positioned relative to the third sensor 88. For example, if the third sensor 88 and the shape measuring unit 90 are positioned at positions that are integer multiples different, it is necessary to rotate the measuring table 82 between the measurement by the third sensor 88 and the measurement by the shape measuring unit 90. In contrast, in the wafer processing apparatus 10 of this embodiment, the three-dimensional shape measurement by the shape measuring unit 90 and the appearance inspection by the third sensor 88 can be performed without rotating the wafer 40. This reduces the time required to rotate the wafer 40 for measurement.

[0109] (4) The control unit 160 simultaneously performs measurement by the shape measuring unit 90 and detection by the third sensor 88 at each measurement interval. Therefore, compared to when these measurements are performed at separate times, the time required for measurement can be shortened, and the efficiency of measuring the wafer 40 can be improved.

[0110] (5) The control unit 160 adjusts the position of the radial shape measuring unit 90 while the wafer 40 is rotating. This shortens the time required to start the measurement compared to the case where the relative position of the optical unit 132 is adjusted after the measurement location 220 is facing the optical unit 132. In this way, the wafer processing apparatus 10 of this embodiment can improve the efficiency of measuring the wafer 40.

[0111] (6) The control unit 160 adjusts the position of the shape measuring unit 90 in the height direction while the wafer 40 is rotated. Therefore, the time required to start measurement is shortened compared to the case where the height position of the optical unit 132 is adjusted after the measurement point 220 is facing the optical unit 132. Therefore, the time required to measure one wafer 40 can be shortened, in other words, the efficiency of wafer 40 measurement can be improved.

[0112] (7) The measuring table 82 rotates in one direction by the table drive unit 122. In a mechanical mechanism, changing the rotation direction of the measuring table 82 can cause backlash. Backlash in the measuring table 82 can cause a misalignment of the actual measurement location relative to the set multiple measurement locations 220. In addition, the spacing of the actually measured locations may differ in the circumferential direction of the wafer 40. In contrast, the measuring unit 20 in the wafer processing apparatus 10 of this embodiment rotates the wafer 40 held on the measuring table 82 in one direction. This allows the shape of the set measurement locations 220 relative to the outer peripheral edge 42 of the wafer 40 to be measured. In other words, the wafer processing apparatus 10 of this embodiment can suppress the misalignment between the measurement locations 220 relative to the wafer 40 and the actual measurement locations.

[0113] (8) In the measurement unit 20, the first sensor 84 and the third sensor 88 are positioned on a straight line passing through the rotation axis G2 of the measurement table 82, with the measurement table 82 in between, when viewed from the height direction (above). In other words, the first sensor 84 and the third sensor 88 are positioned at a central angle of 180 degrees with respect to the rotation axis G2 of the measurement table 82. The second sensor 86 and the shape measurement unit 90 are positioned between the third sensor 88 and the first sensor 84 in the rotation direction of the measurement table 82, that is, in the rotation direction of the wafer 40. In other words, no sensors are positioned between the first sensor 84 and the third sensor 88 in the rotation direction of the measurement table 82. For this reason, the wafer 40 can be easily placed on the holding surface 82A of the measurement table 82 from the side where no sensors are positioned.

[0114] (9) With respect to the rotation axis G2 of the measurement table 82, the shape measuring unit 90 and the third sensor 88 are positioned so that their central angle θ12 is 90 degrees. Therefore, even if the measurement points 220 of the wafer 40 are set at 90-degree intervals, this can be accommodated without changing the arrangement.

[0115] (Example of change) This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0116] In the above embodiment, the diameter and other properties of the wafer 40 before processing were detected by the measuring unit 20. However, a separate section for measuring the wafer 40 before processing may be provided in addition to the measuring unit 20.

[0117] The positions of the first sensor 84, the second sensor 86, the third sensor 88, and the shape measuring unit 90 may be changed as appropriate. For example, the second sensor 86 may be positioned between the shape measuring unit 90 and the first sensor 84. Also, the shape measuring unit 90 and the third sensor 88 may be positioned in this order in the rotational direction of the measuring table 82.

[0118] In the above embodiment, the measurement unit 20 was described using as an example a configuration in which a shape measuring device having a white light interference microscope is provided. However, it is not limited to this, and for example, a shape measuring device having a microscope such as a focus variation type microscope or a laser confocal type microscope may be provided, or a shape measuring device using optical projection measurement may be provided. [Explanation of symbols]

[0119] 10...Wafer processing machine, 12...Supply and recovery unit, 16...Processing unit, 16A...First processing unit, 16B...Second processing unit, 18...Cleaning unit, 20...Measurement unit, 22...Transport unit, 32...Cassette table, 34...Supply and recovery robot, 36...Wafer cassette, 40...Wafer, 42...Outer edge, 42A...Outer edge portion, 42B...Notch portion, 62...Wafer feeding device, 64...Grinding table, 64A...Holding surface, 66...Outer edge grinding device, 72...Cleaning table, 82...Measurement table, 82A...Holding surface, 84...First sensor, 84A...Ejection unit, 84B...Light receiving unit, 86...Second sensor, 86 A...First sensor unit, 86B...Second sensor unit, 88...Third sensor, 88A...First imaging unit, 88B...Second imaging unit, 90...Shape measurement unit, 102...Table drive unit, 104...Position control unit, 106...Grinding wheel drive unit, 112...Grinding wheel, 114...Grinding wheel, 122...Table drive unit, 132...Optical unit, 134...Optical unit drive unit, 136...Light source unit, 138...Beam splitter, 140...Interference objective lens, 142...Imaging lens, 144...Camera, 146...Objective lens, 148...Beam splitter, 150...Reference mirror, 150A...Reference surface, 152...S Scale, 160...Control unit, 162...Measurement control unit, 164...Shape / roughness analysis unit, 166...Feedback calculation unit, 168...Processing control unit, 172...Operation unit, 174...Output unit, 201...Top surface, 202...Bottom surface, 203...End surface, 204...Upper inclined surface, 205...Lower inclined surface, 206...Upper curved surface, 207...Lower curved surface, 211...Upper intersection, 212...Lower intersection, 220...Measurement location, 220A...Measurement location, 220B...Measurement location, 220C...Measurement location, 300...Trueing wheel (Trua), 302...Outer circumference end, 311...Top surface, 312...Bottom surface, 313...End surface, 314...Upper inclined surface Surface, 315...downward inclined surface, 316...upward curved surface, 317...downward curved surface, 321...upper intersection, 322...lower intersection, 402...imaging range, 404...imaging range, 410...imaging data, 412...defect area, 420...imaging range, θ1...inclination angle, θ2...inclination angle, A1...width dimension, A2...width dimension, L1...measurement light, L2...reference light, L3...measurement light, L4...composite light, LA...optical axis, R1...radius, R2...radius, T1...thickness, T2...thickness, UI...operation, X1...height dimension, X2...height dimension, X3...length dimension, AR1...arrow, G1, G2...rotation axis, O1...center, θ11, θ12...central angle.

Claims

1. A wafer processing apparatus for chamfering wafers using a grinding wheel, A measuring table that holds the wafer and is configured to be rotatable, A first sensor for detecting the relative position of the wafer with respect to the measurement table, A shape measuring unit is provided so as to be movable in the radial direction of the measuring table and measures the three-dimensional shape of the outer edge of the wafer using a plurality of imaging data obtained by imaging the outer edge of the wafer from the outside in the radial direction with different focal positions, The wafer processing apparatus comprises a control unit that controls each part of the wafer processing apparatus, The control unit adjusts the position of the shape measuring unit in the radial direction based on the relative position, in a wafer processing apparatus.

2. The system includes a second sensor for detecting the height position of the outer peripheral end in the height direction intersecting the radial direction, The shape measuring unit is provided so as to be movable in the height direction, The wafer processing apparatus according to claim 1, wherein the control unit adjusts the position of the shape measuring unit in the height direction based on the height position.

3. The system includes a third sensor for detecting the appearance of the outer peripheral end, The wafer processing apparatus according to claim 2, wherein the third sensor and the shape measuring unit are positioned at a distance of an integer multiple of the measurement interval measured by the shape measuring unit in the rotational direction of the measuring table around the rotation axis.

4. The wafer processing apparatus according to claim 3, wherein the first sensor, the third sensor, and the second sensor are arranged in the order described above in the rotational direction of the measuring table.

5. The wafer processing apparatus according to claim 3, wherein the control unit simultaneously performs measurement by the shape measuring unit and detection by the third sensor at each measurement interval.

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