TW202517405A - Workpiece processing equipment - Google Patents

Abstract

To provide a workpiece processing apparatus that can process the surface of a workpiece to be flat and process the workpiece to be a target shape. The workpiece processing apparatus 1 comprises: the second measuring mechanism 32 that measures the thickness of the wafer W in a concentric circular manner at multiple measuring positions when the grinding is stopped during the finalized grinding of the wafer W; and the control mechanism 5 that is based on the measurement values obtained by the second measuring mechanism 32 to control the tilting mechanism 13. The control mechanism 5 calculates the concentric circular average values of the measuring positions measured by the second measuring mechanism 32, derives a polynomial curve of the surface shape of the wafer W from the average values, is based on the polynomial curve to control the tilting mechanism 13 to adjust the tilt angle [theta] of the chuck table 12, and then restarts the finalized grinding of the surface Ws of the wafer W.

Description

Workpiece processing equipment

The present invention relates to a workpiece processing device.

In the field of semiconductor manufacturing, workpiece grinding is performed to form a semiconductor wafer such as a silicon wafer (hereinafter also referred to as a "workpiece") into a thin film. As a workpiece processing device for performing such grinding, there is known a workpiece processing device that grinds the workpiece roughly to a thickness thicker than a target shape (target thickness) and then finish grinds the rough-ground workpiece to the target shape.

For example, as a workpiece processing device, there is known a workpiece processing device that temporarily stops grinding during the final grinding of the workpiece and optically measures the thickness of the workpiece at three locations in the radial direction of the grinding position. According to this workpiece processing device, when temporarily stopping grinding and measuring the thickness of the workpiece during the final grinding 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 measuring the thickness of the workpiece, the workpiece is tilted based on the measured thickness of the workpiece, and the final grinding of the workpiece is restarted after the tilt adjustment (for example, refer to Patent Document 1).

[Prior art literature] [Patent literature] [Patent literature 1] Japanese Patent Publication No. 2013-119123

[Problem to be solved by the invention] Here, during the grinding of a workpiece, there may be a portion where the workpiece is not ground to the desired shape, and the thickness may become 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, for example, there is a possibility that one of the three locations may be measured as a specific point.

In this case, the workpiece shape obtained from the measured values at three locations deviates greatly from the actual workpiece shape. Therefore, even if the workpiece is tilted based on the workpiece thickness measured at three locations, it is difficult to suppress the TTV (Total Thickness Variation) of the workpiece to less than or equal to 0.1 μm. Therefore, in the workpiece processing device of Patent Document 1, it is difficult to process the surface of the workpiece into a flat state, and there is a concern that the workpiece cannot be processed into a target shape.

The present invention is made in view of the above circumstances, and its purpose is to provide a workpiece processing device that can process the surface of a workpiece into a flat state and process the workpiece into a target shape.

[Means for Solving the Problem] In order to solve the aforementioned problem, the present invention proposes the following means. <1> A workpiece processing device in one aspect of the present invention is used to process the surface of a workpiece into a flat state, and comprises: a chuck table for rotationally holding the aforementioned workpiece; a workpiece grinding mechanism for grinding the aforementioned surface of the aforementioned workpiece; an optical non-contact measuring mechanism for measuring the thickness of the aforementioned workpiece in a concentric manner at a plurality of radial measuring positions when the aforementioned workpiece grinding mechanism is stopped during grinding; a tilting mechanism for adjusting the tilting angle of the aforementioned chuck table; and a control mechanism. The control mechanism controls the tilt mechanism based on the measured value obtained by the measuring mechanism to adjust the tilt angle of the chuck table; the control mechanism obtains the average values of the concentric circles in the plurality of measured positions measured by the measuring mechanism, obtains the polynomial line in the surface shape of the workpiece from the average values, controls the tilt mechanism based on the polynomial line to adjust the tilt angle of the chuck table, and restarts the grinding of the surface of the workpiece.

According to the workpiece processing device, each average value of the concentric circles in a plurality of measurement positions measured by the measuring mechanism is obtained, and a polynomial line in the surface shape of the workpiece is obtained from each average value. Based on this, the polynomial line can be approximated as the surface shape of the workpiece. Based on this approximated polynomial line, the tilt mechanism is controlled, and the tilt angle of the chuck table is adjusted. Based on this, 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, and the surface of the workpiece can be processed into a flat state. Therefore, the workpiece can be processed into a target shape.

<2> In the workpiece processing device of <1>, the workpiece grinding mechanism comprises at least: a rough grinding section for rough grinding the workpiece; and a fine grinding section for finishing grinding the rough ground workpiece; during the finishing grinding, the inclination angle of the chuck table can be adjusted by controlling the inclination mechanism.

The tilt angle of the chuck table is adjusted during the final grinding according to the workpiece processing device. This can effectively suppress the TTV of the workpiece to a small value and process the surface of the workpiece to a flat state.

<3> In the workpiece processing device of <1> or <2>, the measurement values of the plurality of measurement positions measured by the measurement mechanism may exclude specific points.

According to the workpiece processing device, among the plurality of measured values measured by the measuring mechanism, the tilt angle of the chuck table is adjusted except for the measured value of the specific point. Thus, the polynomial line can be more approximated to the surface shape of the workpiece. Thus, by adjusting the tilt angle of the chuck table, the TTV of the workpiece can be suppressed to a smaller value, and the surface of the workpiece can be processed to a flatter state.

<4> In the workpiece processing device of <3>, the aforementioned characteristic point may be a central portion of the aforementioned workpiece.

Here, when grinding a workpiece, a unique point may exist in the center of the workpiece. Therefore, among the multiple measured values measured by the measuring mechanism, the center of the workpiece is taken as the unique point and the measured value of the center is excluded. According to this, the polynomial line can be more approximated to the surface shape of the workpiece. According to this, by adjusting the tilt angle of the chuck table, the TTV of the workpiece can be suppressed to a smaller value, and the surface of the workpiece can be processed to a flatter state.

[Effect of the invention] According to the present invention, the surface of a workpiece can be processed into a flat state and the workpiece can be processed into a target shape.

In the following, the workpiece processing device of the embodiment of the present invention is described with reference to the drawings. In addition, in the following embodiments, when referring to the number, value, amount, range, etc. of the constituent elements, except for the case where it is specifically stated and the case where it is clearly limited to a specific number in principle, it is not limited to the specific number and may be greater than or equal to the specific number, or less than or equal to the specific number.

Furthermore, when referring to the shape or positional relationship of constituent elements, etc., except when expressly stated otherwise or when it is conceivable in principle that the relationship is obviously different, it includes those that are substantially similar or similar to the shape, etc.

In addition, in order to facilitate the understanding of features, the drawings may exaggerate the features, and the dimensional ratios of the components may not necessarily be the same as the actual ratios. In addition, in order to facilitate the understanding of the cross-sectional structure of the components, the hatching of some components may be omitted in the cross-sectional drawings.

FIG. 1 is a top view showing the basic structure of the workpiece processing device. FIG. 2 is a conceptual diagram illustrating the process of grinding a wafer using the workpiece processing device. As shown in FIG. 1 and FIG. 2, the workpiece processing device 1 is a device that holds the workpiece W at a specified grinding position, processes the surface Ws of the held workpiece W into a flat state, and grinds the workpiece W into a target shape (target thickness) with better accuracy. Hereinafter, the workpiece W is described as "wafer W". Wafer W may be a silicon wafer, a silicon carbide wafer, etc., but is not limited thereto.

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 includes 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.

The indexing table 11 is divided into four platforms, namely, the alignment platform ST1, the rough grinding platform ST2, the intermediate grinding platform ST3, and the fine grinding platform ST4, at equal intervals by the partition plate 15. The four platforms are arranged such that the alignment platform ST1, the rough grinding platform ST2, the intermediate grinding platform ST3, and the fine grinding platform ST4 are arranged in the counterclockwise direction on the paper surface of FIG. 1. Hereinafter, the counterclockwise direction on the paper surface of FIG. 1 may be referred to as the "counterclockwise direction". The partition plate 15 is used to prevent the machining fluid used on each platform from splashing to the adjacent platform.

The indexing table 11 is supported so as to be able to rotate counterclockwise around the rotating shaft 18. Four chuck tables 12 are provided on the indexing table 11. The four chuck tables 12 are provided so as to be able to be arranged on the alignment platform ST1, the rough grinding platform ST2, the intermediate grinding platform ST3, and the fine grinding platform ST4. The indexing table 11 rotates in 90° segments in the counterclockwise direction. Accordingly, the chuck table 12 is sequentially transported (transferred) to the alignment platform ST1, the rough grinding platform ST2, the intermediate grinding platform ST3, and the fine grinding platform ST4 in a counterclockwise manner.

The chuck table 12 is configured to be rotatable around a rotation axis O as a center via a tilt mechanism 13 described later. The chuck table 12 has an adsorbent 12a, which is composed of a ceramic having a porous (porous) structure buried in the upper surface. The chuck table 12 adsorbs the wafer W placed on the adsorbent 12a with negative pressure. Accordingly, 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. That is, the wafer W rotates around the rotation axis O as a center.

The wafer W transported by a transport device (not shown) is held by suction in a state aligned with a designated position on the chuck table 12 of the alignment stage ST1. The wafer W held by suction on the chuck table 12 is rotated 90° counterclockwise by the index table 11 and transported to the rough grinding stage ST2.

The wafer W transferred to the rough grinding stage ST2 has its surface Ws roughly ground (processed) by the rough grinding unit 21 described later. The roughly ground wafer W is rotated 90 degrees counterclockwise by the indexing table 11 and transferred to the intermediate grinding stage ST3.

The wafer W transported to the intermediate grinding stage ST3 is intermediately ground (processed) on the surface Ws by the intermediate grinding section 22 described later. The intermediately ground wafer W is rotated 90° counterclockwise by the indexing table 11 and transported to the fine grinding stage ST4. The wafer W transported to the fine grinding stage ST4 is final ground (finely ground) on the surface Ws by the fine grinding section 23 described later.

The chuck table 12 is provided with a tilt mechanism 13. The tilt mechanism 13 adjusts the tilt angle (tilt angle) θ of the chuck table 12 by tilting the rotation axis O of the chuck table 12 toward the X-Y direction (see FIG. 1 ). Thus, the tilt mechanism 13 can adjust the tilt angle θ of the wafer W held on the chuck table 12.

The workpiece grinding mechanism 3 grinds the surface Ws of the wafer W held on the chuck table 12 in sequence at the rough grinding stage ST2, the intermediate grinding stage ST3, and the fine grinding stage ST4. The workpiece grinding mechanism 3 grinds the surface Ws of the wafer W and processes the wafer W to be thin. The workpiece grinding mechanism 3 includes a rough grinding section 21, an intermediate grinding section 22, and a fine grinding section 23.

The rough grinding section 21 includes a rough grinding grindstone 21a disposed above the rough grinding stage ST2. The rough grinding grindstone 21a is supported by a feeding device (not shown) so as to be able to move up and down. The rough grinding grindstone 21a roughly grinds the surface Ws of the wafer W held on the rough grinding stage ST2.

The middle grinding section 22 includes a middle grinding stone 22a disposed above the middle grinding table ST3. The middle grinding stone 22a is supported by a feeding device (not shown) so as to be able to move up and down. The middle grinding stone 22a grinds the surface Ws of the wafer W disposed on the middle grinding table ST3.

The fine grinding section 23 includes a fine grinding grindstone 23a disposed above the fine grinding table ST4. The fine grinding grindstone 23a is supported by a feeder (not shown) so as to be able to move up and down. The fine grinding grindstone 23a performs finish grinding on the surface Ws of the wafer W disposed on the fine grinding table ST4.

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 stage ST4. The first measuring mechanism 31 is a mechanism for measuring the thickness of the wafer W in an optical non-contact manner. For example, although a spectroscopic interferometer thickness gauge (NCIG, Non-contact In-process Gauge) is used, it is not limited to this. The first measuring mechanism 31 measures the thickness of the wafer W transported to the fine grinding stage ST4.

The second measuring mechanism 32 is, for example, disposed on the fine grinding table ST4. When the fine grinding section 23 of the workpiece grinding mechanism 3 is stopped during grinding, the thickness of the wafer W is measured by the second measuring mechanism 32. Specifically, the second measuring mechanism 32 is, for example, configured to be able to move radially along the surface Ws of the wafer W from the outermost periphery We of the wafer W to the central portion Wc of the wafer W.

The second measuring mechanism 32 is a mechanism for measuring the thickness of the wafer W in an optical non-contact manner. For example, although a spectroscopic interference thickness meter (NCIG) is used, it is not limited to this. While the finishing grinding of the wafer W is stopped on the way and the wafer W is rotated, the second measuring mechanism 32 moves radially along the surface Ws of the wafer W. Accordingly, the second measuring mechanism 32 can measure the thickness of the wafer W in a concentric manner at multiple radial measuring positions. The multiple radial measuring positions of the wafer W are preferably greater than or equal to four. Furthermore, the multiple radial measuring positions of the wafer W are preferably excluding special points. Here, the special point refers to a point where the thickness measurement value is significantly different from the thickness measurement values of other measurement positions. In addition, among the multiple radial measurement positions, the measurement position whose thickness measurement value is significantly different from that of other measurement positions is also called a unique point. In the embodiment, although the unique point is mainly described as the central part Wc of the wafer W, the unique point can also be the central part Wc and the outermost periphery of the wafer W.

Furthermore, in the embodiment, for example, eight or nine positions are used as an example of the plurality of measurement positions in the radial direction of the wafer W. In addition, an example of eight positions as the plurality of measurement positions is described in detail with reference to FIG3. In addition, an example of nine positions as the plurality of measurement positions is described in detail with reference to FIG5 and FIG6.

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. In addition, the function of the control mechanism 5 can be realized by using software control or by using hardware operation.

The control mechanism 5 adjusts the tilt angle θ of the chuck table 12 by controlling the tilt mechanism 13 based on the measured value obtained by the second measuring mechanism 32. That is, the control mechanism 5 obtains the average values of the concentric circles in the plurality of measurement positions measured by the second measuring mechanism 32 in the radial direction. In addition, the control mechanism 5 obtains a polynomial using the obtained average values as monomials, and obtains a polynomial line in the shape of the surface Ws of the wafer W from 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.

Furthermore, the control mechanism 5 controls the tilt mechanism 13 based on the calculated compensation value and adjusts 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 starts grinding the surface Ws of the wafer W again. Hereinafter, the shape of the surface Ws of the wafer W will also be referred to as the "surface shape of the wafer W".

Next, an example of using eight locations as multiple measurement positions in the radial direction of wafer W is described based on FIG3. FIG3 is a graph illustrating multiple measurement positions in the radial direction of wafer W. In FIG3, the vertical axis represents the thickness (THK) of wafer W, and the horizontal axis represents the measurement position of wafer W. G1 represents the surface shape of wafer W. The measurement position in the implementation form is represented by a black circular mark. The measurement position in the comparative example is represented by a white circular mark.

As shown in FIG3 , the comparison example uses three measurement points, namely, the measurement point P10 at the outermost periphery We, the measurement point P11 at the central part Wc, and the measurement point P12 at the center between the outermost periphery We and the central part Wc, in the wafer W. Furthermore, in this comparison example, the measurement is not performed in a concentric manner, but rather at three such points. In this case, any one 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 respect to the polynomial line obtained from the three measurement values of the measurement point P10 at the outermost periphery We, the measurement point P11 at the central part Wc, and the measurement point P12 at the center. Therefore, the tilt angle θ of the wafer W held on the chuck table 12 cannot be properly adjusted based on the polynomial line obtained from the three measured values. As a result, it is difficult to process the surface Ws of the workpiece W into a flat state, and the workpiece W cannot be processed into a target shape.

In this regard, the embodiment uses eight locations P1 to P8 between the outermost periphery We and the central portion Wc of the wafer W as measurement locations, and performs concentric measurements. By excluding the outermost periphery We and the central portion Wc that are likely to become characteristic points, the polynomial line obtained from the eight measurement locations P1 to P8 can approximate the surface shape G1 of the workpiece W. Furthermore, since the concentric measurement is performed, even if a characteristic point is generated in a part of the circumferential direction at any measurement location P1 to P8, its influence can be reduced. Alternatively, the polynomial line can be produced without considering the characteristic point. Accordingly, the correction value for correcting the surface shape of the wafer W is calculated based on the polynomial line obtained from the eight measured positions P1 to P8, and the tilt mechanism 13 is controlled based on the calculated correction value, so that the tilt angle θ of the chuck table 12 can be appropriately adjusted. Accordingly, the tilt angle θ of the wafer W held on the chuck table 12 can be appropriately adjusted. Thus, the surface Ws of the workpiece W can be processed into a flat state, and the workpiece W can be processed into a target shape.

Thus, according to the embodiment, the polynomial line can be approximated with respect to the surface shape of the wafer W by measuring eight positions (P1 to P8) between the outermost periphery We and the central portion Wc in the wafer W. Accordingly, by calculating the shape correction value from the approximated polynomial line, correcting the tilt angle θ (i.e., the grinding angle), and finishing grinding the wafer W again, the surface Ws of the workpiece W can be processed into a flat state, and the workpiece W can be processed into a target shape.

In addition, in the embodiment of FIG3, although eight locations P1 to P8 are described as an example of a plurality of measurement locations, the plurality of measurement locations are not limited to the eight locations P1 to P8. In addition, in the embodiment of FIG3, although an example is described in which the measurement locations do not include both the outermost periphery We and the central portion Wc, the measurement locations may only include one location, the central portion Wc.

Next, the grinding sequence of the wafer W by the workpiece processing device 1 is described based on FIGS. 1 to 6. FIG. 4 is a cross-sectional view showing the surface shape when the grinding is temporarily stopped during the final grinding of the wafer. FIG. 5 is a graph showing the first measurement value of the surface shape of the wafer shown in FIG. 3 measured by the second measuring mechanism. FIG. 6 is a graph showing the second measurement value of the surface shape of the wafer shown in FIG. 3 that has been final-ground again measured by the second measuring mechanism.

Although the following describes an example in which the central portion Wc is used as a distinctive point on the surface Ws of the wafer W, the measurement position P29 of the central portion Wc is excluded, and the tilt angle θ of the chuck table 12 is adjusted, the present invention is not limited to this. For example, the outermost periphery We may be used as a distinctive point on the surface Ws of the wafer W, the measurement position P20 of the outermost periphery We may be excluded, and the tilt angle θ of the chuck table 12 may be adjusted. In addition, the tilt angle θ of the chuck table 12 may be adjusted including the central portion Wc and the outermost periphery We.

1 , in the rough grinding stage ST2 , the surface Ws of the wafer W is roughly ground by the rough grinding grindstone 21 a. After the wafer W is roughly ground, the indexing table 11 rotates 90° counterclockwise in the direction of arrow A. Thus, the wafer W is transferred from the rough grinding stage ST2 to the intermediate grinding stage ST3 .

After the wafer W is transferred to the intermediate grinding stage ST3, the surface Ws of the wafer W is ground by the intermediate grinding grindstone 22a in the intermediate grinding stage ST3. After the intermediate grinding of the wafer W, the indexing table 11 rotates 90 degrees counterclockwise in the direction of arrow A. Thus, the wafer W is transferred from the intermediate grinding stage ST3 to the fine grinding stage ST4.

As shown in FIG. 1 and FIG. 2 , the thickness of the wafer W transported to the fine grinding stage 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 surface Ws of the wafer W is finished ground by the fine grinding grindstone 23a. After the surface Ws of the wafer W is finished ground by the fine grinding grindstone 23a for a specified time (or a specified amount), the finishing grinding of the wafer W is stopped midway while the wafer W is rotated.

As shown in FIGS. 2 to 5 , after the final 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 arrow A while the wafer W is rotated. Accordingly, the thickness of the wafer W is measured for the first time in a concentric manner at the plurality of radial measuring positions P20 to P29 by the second measuring mechanism 32.

Here, in the embodiment, the central portion Wc of the wafer W is described as a unique point on the surface Ws of the wafer W. Accordingly, the measurement value of the measurement position P29 measured by the second measurement mechanism 32 is excluded, and the control mechanism 5 obtains the concentric average values of the measurement values of the measurement positions P20 to P28. In addition, in the embodiment, although the example of excluding the measurement value of the measurement position P29 after measuring a plurality of measurement positions P20 to P29 and obtaining the concentric average values is described, during the measurement, the measurement position P29 may be excluded and the measurement of the measurement positions P20 to P28 may be performed.

The polynomial line G2 in the surface shape of the surface Ws of the wafer W is obtained from each average value obtained by the control mechanism 5. Furthermore, the thickness THK1 of the wafer W and the difference TTV1 between the maximum and minimum values of the thickness of the wafer W are obtained from the polynomial line G2 by the control mechanism 5. In addition, the control mechanism 5 calculates the correction value for correcting the surface shape of the wafer W based on the obtained polynomial line G2. Furthermore, the control mechanism 5 controls the tilt mechanism 13 based on the calculated correction value and adjusts the tilt angle θ of the chuck table 12. Accordingly, the tilt angle θ of the wafer W held on the chuck table 12 can be adjusted. After adjusting the tilt angle θ of the wafer W, the finishing grinding of the surface Ws in the wafer W is started again by the fine grinding grindstone 23a.

As shown in FIG. 2 and FIG. 6, after the surface Ws of the wafer W is ground again with the fine grinding grindstone 23a, the thickness of the wafer W is measured for the second time in a concentric circle at a plurality of radial measurement positions (P20 to P29) by the second measurement mechanism 32. Here, the measurement position P29 in the central portion Wc of the wafer W, which is a characteristic point, is excluded, and the control mechanism 5 is used to obtain the concentric circle average values of the measurement values of the measurement positions P20 to P28. Alternatively, during the measurement, the measurement position P29 is excluded, and the measurement positions P20 to P28 are measured, and the control mechanism 5 is used to obtain the concentric circle average values of the measurement values of the measurement positions P20 to P28.

The control mechanism 5 obtains a polynomial line G3 in the surface shape of the surface Ws of the wafer W from the average values obtained. The control mechanism 5 obtains a thickness THK2 of the wafer W and a difference TTV2 between the maximum and minimum thicknesses of the wafer W from the polynomial line G3.

As shown in Fig. 5 and Fig. 6, 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 to a target shape.

According to the workpiece processing device 1 described above, as shown in FIG2, each average value of the concentric circles in the plurality of measurement positions measured by the second measurement mechanism 32 of the measurement mechanism 4 is obtained, and a polynomial line in the surface shape of the wafer W is obtained from each average value. Accordingly, the polynomial line can be approximated to the surface shape of the wafer W. Based on this approximated polynomial line, the tilt mechanism 13 is controlled, and the tilt angle θ of the chuck table 12 is adjusted. According to this, the tilt angle θ of the wafer W can be adjusted based on the polynomial line. In this state, by restarting the finishing grinding of the surface Ws of the wafer W, the TTV of the wafer W is suppressed to a small value, and the surface Ws of the wafer W can be processed into a flat state. Thus, the wafer W can be processed into a target shape.

In the final grinding of finish grinding the surface Ws of the wafer W, the tilt angle θ of the chuck table 12 is adjusted. This can satisfactorily suppress the TTV of the wafer W to be small, and the surface Ws of the wafer W can be satisfactorily processed to be flat.

Furthermore, the measurement values of the specific points are excluded from the plurality of measurement values measured by the second measurement mechanism 32 of the measurement mechanism 4, and the tilt angle θ of the chuck table 12 is adjusted. Thus, the polynomial line can be more approximated to 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 more effectively suppressed to a small value, and the surface Ws of the wafer W can be more effectively processed to a flat state.

Here, as shown in FIG. 2 and FIG. 4 , when the surface Ws of the wafer W is ground to completion, a characteristic point may exist in the central portion Wc of the wafer W. Therefore, among the multiple measurement values measured by the second measurement mechanism 32 of the measurement mechanism 4, the central portion Wc of the wafer W is used as the characteristic point and the measurement value of the central portion Wc is excluded. Accordingly, the polynomial line can be more approximated to the surface shape of the wafer W. Accordingly, by adjusting the tilt angle θ of the chuck table 12, the TTV of the wafer W can be more effectively suppressed to a small value, and the surface Ws of the wafer W can be more effectively processed to a flat state.

In addition, the technical scope of the present invention is not limited to the aforementioned implementation form, and various changes can be added within the scope that does not violate the purpose of the present invention. For example, in the aforementioned implementation form, as a workpiece grinding mechanism 3, although it is described that there are three grinding parts, namely, a rough grinding part 21, a middle grinding part 22, and a fine grinding part 23, and the wafer W is ground in stages in the rough grinding platform ST2, the middle grinding platform ST3, and the fine grinding platform ST4 of the three grinding platforms, it is not limited to this. As another example, for example, as a workpiece grinding mechanism 3, it can also be configured to have two grinding parts, namely, a rough grinding part 21 and a fine grinding part 23, and the wafer W is ground in stages in the two grinding platforms. Furthermore, the wafer W can be processed in stages in the order of rough grinding, fine grinding, and grinding by using a grinding cloth as the finishing step.

Furthermore, within the scope not violating the spirit of the present invention, the constituent elements in the present embodiment can be appropriately replaced with known constituent elements.

1: Workpiece processing device 2: Holding unit 3: Workpiece grinding mechanism 4: Measuring mechanism 5: Control mechanism 11: Indexing table 12: Chuck table 12a: Adsorption body 13: Tilt mechanism 15: Partition plate 18: Rotation axis 21: Rough grinding section 21a: Rough grinding grindstone 22: Intermediate grinding section 22a: Intermediate grinding grindstone 23: Finishing grinding section 23a: Finishing grinding grindstone 31: First measuring mechanism 32: Second measuring mechanism A: Arrow G1: Surface shape G2: Polynomial line G3: Polynomial line O: Rotation axis P1~P8, P20~P29: Measuring position P10~P12: Measuring point ST1: Alignment platform ST2: Rough grinding platform ST3: Intermediate grinding platform ST4: Fine grinding platform TTV1: Difference TTV2: Difference W: Wafer (workpiece) Wc: Center We: Outermost Ws: Surface θ: Tilt angle

FIG. 1 is a top view showing the basic structure of a workpiece processing device according to an embodiment of the present invention. FIG. 2 is a conceptual diagram showing a process of grinding a wafer by a workpiece processing device according to an embodiment of the present invention. FIG. 3 is a diagram showing a plurality of measurement positions in the radial direction of a wafer W according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing the surface shape when grinding is temporarily stopped during the final grinding of a wafer according to an embodiment of the present invention. FIG. 5 is a diagram showing the first measurement value of the surface shape of the wafer shown in FIG. 3 measured by a second measurement mechanism. FIG. 6 is a diagram showing the second measurement value of the surface shape of the wafer shown in FIG. 3 which has been final-ground again by a second measurement mechanism.

1: Workpiece processing device

4: Measurement mechanism

5: Control mechanism

12: Chuck table

12a: Adsorbent

13: Tilt mechanism

22: Middle grinding department

22a: Medium grinding stone

23: Fine grinding department

23a: Fine grinding grinding stone

31: First measurement agency

32: Second measurement mechanism

A: Arrow

O: Rotation axis

ST3: Medium grinding platform

ST4: Fine grinding platform

W: Wafer (workpiece)

Wc: Central

We: outermost periphery

Ws: surface

θ: Tilt angle

Claims (4)

A workpiece processing device, which is used to process the surface of a workpiece into a flat state, comprises: a chuck table, which rotatably holds the workpiece; a workpiece grinding mechanism, which grinds the surface of the workpiece; an optical non-contact measuring mechanism, which measures the thickness of the workpiece in a concentric manner at a plurality of radial measuring positions while the workpiece grinding mechanism is stopped during grinding; a tilting mechanism, which adjusts the tilt angle of the chuck table; and a control mechanism, which controls the tilting mechanism based on the measured value obtained by the measuring mechanism, thereby adjusting the tilt angle of the chuck table; The control mechanism is to obtain the average values of the concentric circles in the plurality of measurement positions measured by the measurement mechanism, obtain the polynomial line in the surface shape of the workpiece from the average values, control the tilt mechanism based on the polynomial line to adjust the tilt angle of the chuck table, and restart the grinding of the surface of the workpiece. The workpiece processing device as described in claim 1, wherein the workpiece grinding mechanism at least comprises: a rough grinding section for rough grinding the workpiece; and a fine grinding section for finishing the rough ground workpiece; during the finishing grinding, the inclination angle of the chuck table is adjusted by controlling the inclination mechanism. For a workpiece processing device as described in claim 1 or claim 2, the measurement values of the aforementioned multiple measurement positions measured by the aforementioned measuring mechanism exclude specific points. A workpiece processing device as described in claim 3, wherein the aforementioned characteristic point is the central part of the aforementioned workpiece.