Workpiece processing device

Abstract

The invention provides a workpiece machining device which can machine the surface of a workpiece to be flat so as to machine the workpiece into a target shape. The workpiece processing device (1) is provided with: a second measurement mechanism (32) for measuring the thickness of the wafer (W) in a concentric circle shape at a plurality of measurement positions of the wafer (W) in a state in which grinding is stopped during fine grinding of the wafer (W); and a control means (5) for controlling the tilting means (13) on the basis of the measurement value obtained by the second measurement means (32). The control mechanism (5) is configured to obtain the average values of the concentric circles of the plurality of measurement positions measured by the second measurement mechanism (32), obtain the polynomial line of the surface shape of the wafer (W) according to the average values, and control the inclination mechanism (13) based on the polynomial line to adjust the inclination angle (theta) of the chuck table (12). And resuming the fine grinding of the surface (Ws) of the wafer (W).

Description

Technical Field

[0001] The invention relates to a workpiece processing device. Background Art

[0002] In the field of semiconductor manufacturing, in order to form a semiconductor wafer such as a silicon wafer (hereinafter sometimes referred to as a "workpiece") into a thin film, the workpiece is ground. As a workpiece processing device for performing such grinding, there is known a workpiece processing device that roughly grinds the workpiece to be thicker than a target shape (target thickness) and then finely grinds the roughly ground workpiece to a target shape.

[0003] For example, as a workpiece processing device, there is known a device that temporarily stops grinding during fine grinding of a workpiece and optically measures the thickness of the workpiece at three locations in the radial direction at the grinding position. According to this workpiece processing device, when temporarily stopping grinding during fine grinding of a workpiece to measure the thickness of the workpiece, the rotation of the workpiece is stopped and the thickness of the workpiece is measured at three locations in the radial direction between the center and the outermost periphery of the workpiece. After the thickness of the workpiece is measured, the workpiece is tilted based on the measured thickness of the workpiece, and the fine grinding of the workpiece is restarted after the tilt adjustment (for example, refer to Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-119123

[0005] Here, when grinding a workpiece, sometimes the workpiece is not ground into a desired shape, and a portion of the workpiece is too thick or too thin. Therefore, as in the workpiece processing device of Patent Document 1, when the rotation of the workpiece is stopped and the thickness of the workpiece is measured at three locations in the radial direction, it is possible to measure a singular point at, for example, one of the three locations.

[0006] In this case, the shape of the workpiece obtained based on the measured values ​​at the three locations will deviate significantly from the actual shape of the workpiece. Therefore, even if the workpiece is tilted based on the thickness of the workpiece measured at the three locations, it is difficult to suppress the TTV (Total Thickness Variation) of the workpiece to a small amount of less than 0.1 μm. Therefore, it is difficult for the workpiece processing device of Patent Document 1 to process the surface of the workpiece flat, and it may not be possible to process the workpiece into a target shape. Summary of the invention

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a workpiece processing device that can process the surface of a workpiece to be flat, thereby processing the workpiece into a target shape.

[0008] In order to solve the above-mentioned problems, the present invention proposes the following means.

[0009] (1) A workpiece processing device according to one embodiment of the present invention is a workpiece processing device for processing the surface of a workpiece to be flat, comprising: a chuck table for rotating and holding the workpiece; a workpiece grinding mechanism for grinding the surface of the workpiece; an optical non-contact measuring mechanism for measuring the thickness of the workpiece in a concentric circle at a plurality of measuring positions in the radial direction of the workpiece while the grinding by the workpiece grinding mechanism is stopped halfway; a tilting mechanism for adjusting the tilt angle of the chuck table; and a control mechanism for controlling the tilting mechanism based on a measurement value obtained by the measuring mechanism to adjust the tilt angle of the chuck table, the control mechanism being configured to: obtain average values ​​of the concentric circles of the plurality of measuring positions measured by the measuring mechanism, obtain a polynomial line of the surface shape of the workpiece based on the average values, control the tilting mechanism based on the polynomial line to adjust the tilt angle of the chuck table, and restart grinding the surface of the workpiece.

[0010] According to the workpiece processing device, each average value of the concentric circles of the plurality of measurement positions measured by the measuring mechanism is obtained, and a polynomial line of the surface shape of the workpiece is obtained based on each average value. Therefore, the polynomial line can be approximated to the surface shape of the workpiece. The tilting mechanism is controlled based on the approximated polynomial line to adjust the tilt angle of the chuck table. Thus, the tilt angle of the workpiece can be adjusted based on the polynomial line. In this state, by restarting the grinding of the surface of the workpiece, the TTV of the workpiece can be suppressed to a small value, thereby processing the surface of the workpiece to be flat. Thus, the workpiece can be processed into a target shape.

[0011] (2) In the workpiece processing device of the above (1), the workpiece grinding mechanism may also include at least a rough grinding section for performing rough grinding on the workpiece and a fine grinding section for performing fine grinding on the workpiece after the rough grinding, and during the fine grinding, the inclination angle of the chuck table is adjusted by controlling the inclination mechanism.

[0012] According to the workpiece processing device, the inclination angle of the chuck table is adjusted during finish grinding, thereby making it possible to suppress the TTV of the workpiece to be small and process the surface of the workpiece to be flat.

[0013] (3) In the workpiece processing device according to (1) or (2) above, the measurement values ​​of the plurality of measurement positions measured by the measurement mechanism may be free of singular points.

[0014] According to the workpiece processing device, the measured value of the singular point is removed from the plurality of measured values ​​measured by the measuring mechanism to adjust the inclination angle of the chuck table. Therefore, the polynomial line can be further approximated as the surface shape of the workpiece. Thus, by adjusting the inclination angle of the chuck table, the TTV of the workpiece can be further suppressed to be small, thereby further processing the surface of the workpiece to be flat.

[0015] (4) In the workpiece processing device according to (3) above, the singular point may be a central portion of the workpiece.

[0016] Here, when grinding a workpiece, a singular point sometimes exists in the center of the workpiece. Therefore, among the multiple measurement values ​​measured by the measuring mechanism, the center of the workpiece is taken as the singular point to remove the measurement value of the center. Therefore, the polynomial line can be further approximated as the surface shape of the workpiece. Thus, by adjusting the inclination angle of the chuck table, the TTV of the workpiece can be further suppressed to a smaller value and the surface of the workpiece can be further processed to be flat.

[0017] According to the present invention, the surface of a workpiece can be processed to be flat, thereby processing the workpiece into a target shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a plan view showing the basic structure of the workpiece processing device according to the embodiment of the present invention.

[0019] Figure 2 This is a conceptual diagram for explaining the process of grinding a wafer using the workpiece processing apparatus according to this embodiment.

[0020] Figure 3 1 is a graph for explaining a plurality of measurement positions in the radial direction of the wafer W according to this embodiment.

[0021] Figure 4 This is a cross-sectional view showing the surface shape when grinding is temporarily stopped during finish grinding of the wafer according to this embodiment.

[0022] Figure 5 The second measuring mechanism is used to measure Figure 3 Shown is a graph of the first measured values ​​of the surface shape of the wafer.

[0023] Figure 6 The second measuring mechanism is used to measure the re-finishing grinding. Figure 3 Shown is a graph of the second measurement values ​​of the surface shape of the wafer. DETAILED DESCRIPTION

[0024] Hereinafter, a workpiece processing device according to an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that in the following embodiments, when the number, value, amount, range, etc. of structural elements are mentioned, except for cases where it is specifically stated or the case where it is obviously limited to a specific number in principle, it is not limited to the specific number and can be more than or less than the specific number.

[0025] Furthermore, when referring to the shape or positional relationship of a component or the like, shapes that are substantially close to or similar to the shape or the like are included, except for cases where it is particularly noted or where it is obvious that this is not the case in principle.

[0026] In addition, in the drawings, the features are sometimes exaggerated such as enlarged to facilitate understanding of the features, and the size ratios of the structural elements are not necessarily the same as the actual ones. In addition, in the cross-sectional views, the hatching of some structural elements is sometimes omitted to facilitate understanding of the cross-sectional structure of the structural elements.

[0027] Figure 1 It is a top view showing the basic structure of the workpiece processing device. Figure 2 This is a conceptual diagram for explaining the process of grinding a wafer using a workpiece processing apparatus.

[0028] like Figure 1 , Figure 2 As shown, the workpiece processing device 1 is a device that holds the workpiece W at a predetermined grinding position and grinds the workpiece W into a target shape (target thickness) with high precision by processing the surface Ws of the held workpiece W to be flat. Hereinafter, the workpiece W is described as a "wafer W". Although the wafer W is a silicon wafer, a silicon carbide wafer, etc., it is not limited thereto.

[0029] The workpiece processing device 1 includes a holding unit 2, a workpiece grinding mechanism 3, a measuring mechanism 4, and a control mechanism 5. The holding unit 2 has an indexing table 11, a chuck table 12, and a tilting mechanism 13. A partition plate 15 is provided above the indexing table 11. The partition plate 15 is formed in a cross shape.

[0030] The indexing table 11 is divided into four tables, namely, an alignment table ST1, a rough grinding table ST2, a medium grinding table ST3, and a fine grinding table ST4, at equal intervals by a partition plate 15. Figure 1 On the paper of FIG. 1, an alignment table ST1, a rough grinding table ST2, a medium grinding table ST3 and a fine grinding table ST4 are sequentially arranged in a counterclockwise direction. Figure 1 The counterclockwise direction on the paper surface of FIG. 1 is simply referred to as “counterclockwise direction.” The partition plate 15 prevents the machining fluid used in each worktable from scattering to the adjacent worktable.

[0031] The indexing table 11 is supported so as to be rotatable counterclockwise about the rotating shaft 18. Four chuck tables 12 are provided on the indexing table 11. The four chuck tables 12 are provided on the indexing table 11 so as to be arranged on the alignment table ST1, the rough grinding table ST2, the intermediate grinding table ST3, and the fine grinding table ST4.

[0032] The indexing table 11 rotates 90 degrees in each step in the counterclockwise direction. As a result, the chuck table 12 is sequentially conveyed (transferred) in the counterclockwise direction to the alignment table ST1, the rough grinding table ST2, the intermediate grinding table ST3, and the fine grinding table ST4.

[0033] The chuck table 12 is configured to be rotatable around the rotation axis O via a tilting mechanism 13 described later. The chuck table 12 has an adsorbent 12a made of ceramic with a porous structure buried in the upper surface. The chuck table 12 uses negative pressure to adsorb the wafer W placed on the adsorbent 12a. As a result, the center of the wafer W is aligned with the rotation axis O of the chuck table 12, and the wafer W is vacuum-adsorbed to the adsorbent 12a to be rotated and held as a whole. In other words, the wafer W rotates around the rotation axis O.

[0034] On the chuck table 12 of the alignment table ST1, the wafer W transported by a transport device (not shown) is held by suction in a predetermined position. The index table 11 is rotated 90° counterclockwise to transport the wafer W held by suction on the chuck table 12 to the rough grinding table ST2.

[0035] The surface Ws of the wafer W transferred to the rough grinding stage ST2 is roughly ground (processed) by the rough grinding unit 21 described later. The roughly ground wafer W is transferred to the intermediate grinding stage ST3 by the counterclockwise rotation of the indexing table 11.

[0036] The surface Ws of the wafer W transferred to the intermediate grinding table ST3 is intermediately ground (processed) by the intermediate grinding section 22 described later. The wafer W after the intermediate grinding is transferred to the finish grinding table ST4 by the index table 11 rotating counterclockwise by 90 degrees.

[0037] The surface Ws of the wafer W conveyed to the finishing grinding stage ST4 is finish ground (precision grinding) by the finishing grinding section 23 described later.

[0038] The chuck table 12 is provided with a tilting mechanism 13. The tilting mechanism 13 tilts the rotation axis O of the chuck table 12 in the XY direction (see Figure 1 ) is tilted upward to adjust the tilt angle (inclination angle) θ of the chuck table 12. Therefore, the tilt mechanism 13 can adjust the tilt angle θ of the wafer W held by the chuck table 12.

[0039] The workpiece grinding mechanism 3 grinds the surface Ws of the wafer W held by the chuck table 12 on the rough grinding table ST2, the intermediate grinding table ST3, and the fine grinding table ST4 in sequence. The workpiece grinding mechanism 3 grinds the surface Ws of the wafer W to make the wafer W thinner. The workpiece grinding mechanism 3 includes a rough grinding section 21, an intermediate grinding section 22, and a fine grinding section 23.

[0040] The rough grinding section 21 includes a rough grinding tool 21a disposed above the rough grinding table ST2. The rough grinding tool 21a is supported by a feed device (not shown) so as to be able to move up and down. The rough grinding tool 21a rough grinds the surface Ws of the wafer W held on the rough grinding table ST2.

[0041] The intermediate grinding section 22 includes an intermediate grinding tool 22a disposed above the intermediate grinding table ST3. The intermediate grinding tool 22a is supported by a feed device (not shown) so as to be able to move up and down. The intermediate grinding tool 22a performs intermediate grinding on the surface Ws of the wafer W disposed on the intermediate grinding table ST3.

[0042] The fine grinding section 23 includes a fine grinding tool 23a disposed above the fine grinding table ST4. The fine grinding tool 23a is supported by a feed device (not shown) so as to be able to move up and down in the vertical direction. The fine grinding tool 23a fine grinds the surface Ws of the wafer W disposed on the fine grinding table ST4.

[0043] The measuring mechanism 4 includes a first measuring mechanism 31 and a second measuring mechanism 32. The first measuring mechanism 31 is, for example, disposed on the fine grinding table ST4. The first measuring mechanism 31 measures the thickness of the wafer W in an optical non-contact manner, for example, using a spectral interference thickness gauge (NCIG: Non-contact In-process Gauge), but is not limited thereto. The first measuring mechanism 31 measures the thickness of the wafer W transported to the fine grinding table ST4.

[0044] The second measuring mechanism 32 is disposed, for example, on the fine grinding table ST4. The second measuring mechanism 32 measures the thickness of the wafer W in a state where the fine grinding unit 23 of the workpiece grinding mechanism 3 is stopped midway. Specifically, the second measuring mechanism 32 is configured to be movable radially from the outermost periphery We of the wafer W along the surface Ws of the wafer W to the center Wc of the wafer W, for example.

[0045] The second measuring mechanism 32 measures the thickness of the wafer W in an optical non-contact manner, for example, using a spectral interference thickness gauge (NCIG), but the present invention is not limited thereto.

[0046] The second measuring mechanism 32 moves radially along the surface Ws of the wafer W while stopping the fine grinding of the wafer W midway and rotating the wafer W. Thus, the second measuring mechanism 32 can measure the thickness of the wafer W in a concentric circle at multiple radial measuring positions. The multiple radial measuring positions of the wafer W are preferably four or more, for example. Furthermore, it is preferred to remove singular points from the multiple radial measuring positions of the wafer W. Here, the so-called singular point refers to a point where the thickness measurement value is significantly different from the thickness measurement values ​​at other measuring positions. In addition, among the multiple radial measuring positions, the measuring position where the thickness measurement value is significantly different from the thickness measurement values ​​at other measuring positions is also referred to as a singular point. In the embodiment, the singular point is mainly set to the central part Wc of the wafer W for explanation, but the singular point may also be set to the central part Wc and the outermost periphery We of the wafer W.

[0047] Furthermore, in the embodiment, for example, eight or nine locations are used as the plurality of measurement locations in the radial direction of the wafer W. It should be noted that, regarding the example of setting the plurality of measurement locations to eight locations, Figure 3 In addition, regarding the example of setting the multiple measurement positions to nine, Figure 5 , Figure 6 The details are explained in detail in .

[0048] The control mechanism 5 controls the operation of the components constituting the workpiece processing device 1. The control mechanism 5 is composed of, for example, a CPU (Central Processing Unit), a memory, etc. It should be noted that the function of the control mechanism 5 can be realized by control using software or by operation using hardware.

[0049] The control mechanism 5 controls the tilt mechanism 13 based on the measurement value obtained by the second measurement mechanism 32, thereby adjusting the tilt angle θ of the chuck table 12. That is, the control mechanism 5 obtains the average values ​​of the concentric circles at the plurality of measurement positions measured by the second measurement mechanism 32 in the radial direction. In addition, the control mechanism 5 obtains a polynomial in which the obtained average values ​​are set as a monomial, and obtains a polynomial line of the shape of the surface Ws of the wafer W based on the polynomial. Furthermore, the control mechanism 5 calculates a correction value for correcting the surface shape of the wafer W based on the obtained polynomial line.

[0050] In addition, the control mechanism 5 controls the tilt mechanism 13 based on the calculated correction value to adjust the tilt angle θ of the chuck table 12. Furthermore, after adjusting the tilt angle θ of the chuck table 12, the control mechanism 5 restarts the grinding of the surface Ws of the wafer W. Hereinafter, the shape of the surface Ws of the wafer W is sometimes referred to as the "surface shape of the wafer W".

[0051] Next, based on Figure 3 An example in which the number of measurement positions on the wafer W in the radial direction is set to eight will be described.

[0052] Figure 3 Graphs are provided to illustrate multiple measurement positions of the wafer W in the radial direction. Figure 3 In FIG. 1 , the vertical axis indicates the thickness (THK (Thickness)) of the wafer W, and the horizontal axis indicates the measurement position of the wafer W. The surface shape of the wafer W is indicated by G1. The measurement position in the embodiment is indicated by a black circle. The measurement position in the comparative example is indicated by a white circle.

[0053] like Figure 3 As shown in FIG. 1 , in the comparative example, three points are set as measurement points: the measurement point P10 at the outermost periphery We of the wafer W, the measurement point P11 at the central portion Wc, and the measurement point P12 at the center between the outermost periphery We and the central portion Wc. Furthermore, in this comparative example, the measurement is not performed in a concentric circle shape, but these three points are set as measurement points. In this case, any of the three measurement points P10, P11, and P12 may become a unique point. Therefore, it is impossible to approximate the surface shape G1 of the workpiece W with the polynomial line obtained from the measurement values ​​of the three points: the measurement point P10 at the outermost periphery We, the measurement point P11 at the central portion Wc, and the measurement point P12 at the center.

[0054] Therefore, the inclination angle θ of the wafer W held by the chuck table 12 cannot be appropriately adjusted based on the polynomial line obtained from the measured values ​​at three locations. As a result, it is difficult to flatten the surface Ws of the workpiece W, and the workpiece W cannot be processed into a target shape.

[0055] In contrast, in the embodiment, eight positions P1 to P8 are set as measurement positions between the outermost periphery We and the central portion Wc of the wafer W, and the measurement is performed in a concentric circle shape. By removing the outermost periphery We and the central portion Wc that are likely to become singular points, the polynomial line obtained from the eight measurement positions P1 to P8 can be approximated with respect to the surface shape G1 of the workpiece W. Furthermore, since the measurement is performed in a concentric circle shape, even if a singular point occurs in a part of the circumferential direction at any measurement position P1 to P8, its influence can be reduced. Alternatively, the polynomial line can be prepared without considering the singular point.

[0056] Therefore, the correction value for correcting the surface shape of the wafer W can be calculated based on the polynomial line obtained from the eight measurement positions P1 to P8, and the tilt mechanism 13 can be controlled based on the calculated correction value to appropriately adjust the tilt angle θ of the chuck table 12. Therefore, the tilt angle θ of the wafer W held by the chuck table 12 can be appropriately adjusted. As a result, the surface Ws of the workpiece W can be processed to be flat and the workpiece W can be processed into a target shape.

[0057] Thus, according to the embodiment, the polynomial line can be approximated with respect to the surface shape of the wafer W by using the eight measurement positions P1 to P8 between the outermost periphery We and the central portion Wc of the wafer W. Thus, the shape correction value can be calculated based on the approximated polynomial line, and the tilt angle θ (i.e., the grinding angle) can be corrected, and the wafer W can be finely ground again, thereby processing the surface Ws of the workpiece W to be flat and processing the workpiece W to a target shape.

[0058] It should be noted that Figure 3 In the embodiment of the present invention, although eight locations P1 to P8 are used as an example of multiple measurement locations, the multiple measurement locations are not limited to the eight locations P1 to P8. Figure 3 In the embodiment, although the case where the measurement position does not include both the outermost periphery We and the central portion Wc is described as an example, the measurement position may only not include the central portion Wc.

[0059] Next, based on Figure 1 to Figure 6 The steps of grinding the wafer W by the workpiece processing apparatus 1 will be described.

[0060] Figure 4 This is a cross-sectional view showing the surface shape when grinding is temporarily stopped during finish grinding of the wafer. Figure 5 The second measuring mechanism is used to measure Figure 3 Shown is a graph of the first measured values ​​of the surface shape of the wafer. Figure 6 The second measuring mechanism is used to measure the Figure 3 The graph of the second measurement value of the surface shape of the wafer after fine grinding is shown.

[0061] In the following, although an example is described in which the singular point on the surface Ws of the wafer W is set as the central portion Wc, and the measurement position P29 of the central portion Wc is excluded to adjust the inclination angle θ of the chuck table 12, the present invention is not limited thereto. For example, the singular point on the surface Ws of the wafer W may be set as the outermost periphery We, and the measurement position P20 of the outermost periphery We may be excluded to adjust the inclination angle θ of the chuck table 12. In addition, the inclination angle θ of the chuck table 12 may be adjusted including the central portion Wc and the outermost periphery We.

[0062] like Figure 1 As shown, the surface Ws of the wafer W is roughly ground by the rough grinding tool 21a on the rough grinding table ST2. After the wafer W is roughly ground, the indexing table 11 is rotated 90° counterclockwise in the direction of arrow A. Thus, the wafer W is transferred from the rough grinding table ST2 to the intermediate grinding table ST3.

[0063] After the wafer W is transferred to the intermediate grinding station ST3, the intermediate grinding tool 22a performs intermediate grinding on the surface Ws of the wafer W. After the intermediate grinding of the wafer W, the indexing table 11 is rotated 90 degrees counterclockwise in the direction of arrow A. Thus, the wafer W is transferred from the intermediate grinding station ST3 to the fine grinding station ST4.

[0064] like Figure 1 , Figure 2 As shown, the thickness of the wafer W transported to the fine grinding worktable ST4 is measured by the first measuring mechanism 31. Based on the thickness of the wafer W measured by the first measuring mechanism 31, the fine grinding of the surface Ws of the wafer W is started by the fine grinding tool 23a. After the surface Ws of the wafer W is fine ground by the fine grinding tool 23a for a predetermined time (or a predetermined amount), the fine grinding of the wafer W is stopped midway while the wafer W is rotated.

[0065] like Figures 2 to 5 As shown in the figure, after the fine grinding of the wafer W is stopped midway, the second measuring mechanism 32 is moved radially along the surface Ws of the wafer W as indicated by the arrow A while the wafer W is rotated. Thus, the thickness of the wafer W is first measured concentrically at the plurality of radial measurement positions P20 to P29 by the second measuring mechanism 32.

[0066] Here, in the embodiment, the central portion Wc of the wafer W is described as a singular point on the surface Ws of the wafer W. Therefore, excluding the measurement value of the measurement position P29 measured by the second measurement mechanism 32, the control mechanism 5 obtains the concentric average values ​​of the measurement values ​​of the measurement positions P20 to P28.

[0067] It should be noted that, in the embodiment, an example is described in which after measuring a plurality of measurement positions P20 to P29, the measurement value of measurement position P29 is removed to obtain concentric circle average values. However, measurement positions P20 to P28 may be measured while removing measurement position P29.

[0068] The polynomial line G2 of the surface shape of the surface Ws of the wafer W is obtained based on the average values ​​obtained by the control mechanism 5. Furthermore, the thickness THK1 of the wafer W and the difference TTV1 between the maximum value and the minimum value of the thickness of the wafer W are obtained by the control mechanism 5 based on the polynomial line G2. In addition, the control mechanism 5 calculates a correction value for correcting the surface shape of the wafer W based on the obtained polynomial line G2. In addition, the control mechanism 5 controls the tilt mechanism 13 based on the calculated correction value, thereby adjusting the tilt angle θ of the chuck table 12.

[0069] This makes it possible to adjust the tilt angle θ of the wafer W held by the chuck table 12. After the tilt angle θ of the wafer W is adjusted, the finish grinding of the surface Ws of the wafer W is resumed using the finish grinding stone 23a.

[0070] like Figure 2 , Figure 6 As shown in FIG. 1 , after the surface Ws of the wafer W is finely ground again by the fine grinding tool 23a, the thickness of the wafer W is secondly measured in a concentric circle at a plurality of radial measurement positions P20 to P29 by the second measuring mechanism 32. Here, the measured value at the measurement position P29 at the center portion Wc of the wafer W as a singular point is excluded, and the control mechanism 5 obtains the concentric average values ​​of the measured values ​​at the measurement positions P20 to P28.

[0071] Alternatively, measurement is performed at measurement positions P20 to P28 excluding measurement position P29 , and the control mechanism 5 obtains concentric circle average values ​​of the measurement values ​​at measurement positions P20 to P28 .

[0072] The polynomial line G3 of the surface shape of the surface Ws of the wafer W is obtained from the average values ​​obtained by the control mechanism 5. Furthermore, the thickness THK2 of the wafer W and the difference TTV2 between the maximum and minimum values ​​of the thickness of the wafer W are obtained by the control mechanism 5 from the polynomial line G3.

[0073] like Figure 5 , Figure 6 As shown, TTV2 in the second measurement can be suppressed to be smaller than TTV1 in the first measurement. Thus, the surface Ws of the workpiece W can be processed to be flat, and the workpiece W can be processed into a target shape.

[0074] According to the workpiece processing device 1 described above, Figure 2 As shown, each average value of the concentric circles of the plurality of measurement positions measured by the second measurement mechanism 32 of the measurement mechanism 4 is obtained, and a polynomial line of the surface shape of the wafer W is obtained based on each average value. Therefore, the polynomial line can be approximated to the surface shape of the wafer W. The tilt mechanism 13 is controlled based on the approximated polynomial line to adjust the tilt angle θ of the chuck table 12.

[0075] Thus, the tilt angle θ of the wafer W can be adjusted based on the polynomial line. In this state, the finish grinding of the surface Ws of the wafer W is started again, so that the TTV of the wafer W can be suppressed to a small level and the surface Ws of the wafer W can be processed flat. Thus, the wafer W can be processed into a target shape.

[0076] In addition, the inclination angle θ of the chuck table 12 is adjusted during the finish grinding of the surface Ws of the wafer W. Thus, the TTV of the wafer W can be satisfactorily suppressed to be small and the surface Ws of the wafer W can be satisfactorily processed to be flat.

[0077] Furthermore, the tilt angle θ of the chuck table 12 is adjusted by removing the measured value of the singular point from the plurality of measured values ​​measured by the second measuring mechanism 32 of the measuring mechanism 4. Therefore, the polynomial line can be further approximated as the surface shape of the wafer W. Thus, by adjusting the tilt angle θ of the chuck table 12, the TTV of the wafer W can be further suppressed to be small and the surface Ws of the wafer W can be further processed to be flat.

[0078] Here, if Figure 2 , Figure 4 As shown in FIG. 1 , when the surface Ws of the wafer W is finely ground, a singular point may exist in the central portion Wc of the wafer W. Therefore, among the plurality of measurement values ​​measured by the second measurement mechanism 32 of the measurement mechanism 4, the central portion Wc of the wafer W is set as the singular point and the measurement value of the central portion Wc is removed. Therefore, the polynomial line can be further approximated as the surface shape of the wafer W. Thus, by adjusting the inclination angle θ of the chuck table 12, the TTV of the wafer W can be further suppressed to be small and the surface Ws of the wafer W can be further processed to be flat.

[0079] It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

[0080] For example, in the above-mentioned embodiment, although the example in which the three grinding parts of the rough grinding part 21, the intermediate grinding part 22 and the fine grinding part 23 are provided as the workpiece grinding mechanism 3, and the wafer W is ground in stages on the three grinding workstations ST2, ST3, and ST4 is described, it is not limited to this. As another example, for example, it is also possible to configure that the two grinding parts of the rough grinding part 21 and the fine grinding part 23 are provided as the workpiece grinding mechanism 3, and the wafer W is ground in stages on the two grinding workstations. Furthermore, the fine processing step can also be set as a grinding process performed by a grinding cloth, and the wafer W can be processed in stages in the order of rough grinding, fine grinding, and grinding.

[0081] Furthermore, the components in the present embodiment can be appropriately replaced with known components without departing from the spirit of the present invention.

[0082] Description of Reference Numerals

[0083] 1Workpiece processing device

[0084] 2 Holding unit

[0085] 3. Workpiece grinding mechanism

[0086] 4. Measurement mechanism

[0087] 5 Control mechanism

[0088] 11 Indexing table

[0089] 12 chuck tables

[0090] 13. Tilt mechanism

[0091] 21 Rough grinding department

[0092] 22 Grinding Department

[0093] 23 Fine grinding department

[0094] 32 Second measurement mechanism

[0095] W wafer (workpiece)

[0096] Wc The center of the wafer

[0097] We The outermost periphery of the chip

[0098] Surface of Ws wafer

[0099] θ Tilt angle

Claims

1. A workpiece processing device for processing the surface of a workpiece into a flat surface, characterized in that: have: A chuck table, used for rotating and holding the workpiece; A workpiece grinding mechanism, used for grinding the surface of the workpiece; An optical non-contact measuring mechanism for measuring the thickness of the workpiece in a concentric circle at a plurality of measuring positions in the radial direction of the workpiece while the grinding by the workpiece grinding mechanism is stopped midway; A tilting mechanism, used to adjust the tilting angle of the chuck table; as well as a control mechanism for controlling the tilting mechanism based on the measurement value obtained by the measuring mechanism to adjust the tilting angle of the chuck table, The control mechanism is configured to: calculate the concentric circle average values ​​of the multiple measurement positions measured by the measuring mechanism, calculate the polynomial line of the surface shape of the workpiece based on the average values, control the tilting mechanism based on the polynomial line to adjust the tilt angle of the chuck table, and start grinding the surface of the workpiece again.

2. The workpiece processing device according to claim 1, characterized in that: The workpiece grinding mechanism includes at least a rough grinding section for performing rough grinding on the workpiece and a fine grinding section for performing fine grinding on the workpiece after the rough grinding. In the finish grinding, the tilting mechanism is controlled to adjust the tilting angle of the chuck table.

3. The workpiece processing device according to claim 1 or 2, characterized in that: The measurement values ​​of the plurality of measurement positions measured by the measurement mechanism are free of singular points.

4. The workpiece processing device according to claim 3, characterized in that: The singular point is a central portion of the workpiece.

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