Work-piece processing device

Abstract

To provide a work-piece processing device that can adjust variation in thickness in a support member and a thickness of a work-piece in consideration of thermal effect on the work-piece, so as to improve productivity.SOLUTION: A work-piece processing device 1 comprises, as measurement mechanisms 4, a first measurement mechanism 31 that measures a thickness of a wafer W while conveying the wafer after the wafer is processed in a middle grinding stage ST3 and a second measurement mechanism 32 that measures a thickness of the wafer W while conveying the wafer after the wafer is processed in a fine grinding stage ST4. An inclination angle θ of a chuck table 12 in the fine grinding stage ST4 is adjusted on the basis of a measured value by the first measurement mechanism 31. A measured value by the second measurement mechanism 32 is added in adjusting the inclination angle θ of the chuck table 12 in the fine grinding stage ST4.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a workpiece machining device. [Background technology]

[0002] In the field of semiconductor manufacturing, semiconductor wafers such as silicon wafers (hereinafter sometimes referred to as "workpieces") are ground to form them into thin films. Known workpiece processing devices for performing such grinding include those that roughly grind the workpiece to a thickness greater than a target shape (target thickness) and then fine-grind the workpiece after rough grinding to the target shape.

[0003] For example, a workpiece processing device is known that measures the thickness of a workpiece at each grinding position after rough grinding and then fine grinding the workpiece. With this workpiece processing device, the shape of the workpiece after rough grinding can be reflected in tilt adjustment in fine grinding, and the shape of the workpiece after fine grinding can be reflected in grinding of the next workpiece (for example, see Patent Document 1).

[0004] Also, a workpiece processing device is known that includes a rough grinding stage for rough grinding the workpiece, a fine grinding stage for fine grinding the workpiece, and a thickness measuring means for measuring the thickness of the workpiece while the workpiece is being transported. This workpiece processing device makes it possible to correct the target shape after fine grinding based on the average thickness of the entire surface of the workpiece before fine grinding obtained from the measurement value of the thickness measuring means, and calculate the corrected target shape (see, for example, Patent Document 2).

[0005] Furthermore, there is known a workpiece processing device that temporarily stops grinding (finishing) the workpiece during the grinding and optically measures the thickness of the workpiece at three radial points at the grinding position. According to this workpiece processing device, the tilt of the workpiece is adjusted based on the thickness of the workpiece measured by temporarily stopping grinding, and fine grinding of the workpiece is resumed after the tilt adjustment (for example, see Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-201422 A [Patent Document 2] JP 2018-122368 A [Patent Document 3] JP 2013-119123 A Summary of the Invention [Problem to be solved by the invention]

[0007] Here, for example, in order to improve the performance of semiconductor devices, the thickness of the workpiece on which a functional layer is formed is being reduced, but the workpiece alone is too thin and difficult to handle. For this reason, it is necessary to attach the workpiece to a support member to facilitate handling such as transportation and grinding. When processing a workpiece attached to a support member using the workpiece processing device of Patent Documents 1 to 3, it is possible to measure the thickness of the workpiece by assuming the support member to be flat. However, the support member is not completely flat and has a variation in thickness. In particular, for example, when the TTV (Total Thickness Variation) of the workpiece is set to 0.1 μm, it is difficult to accurately adjust the thickness of the workpiece without considering the variation in the thickness of the support member.

[0008] On the other hand, in order to adjust the thickness of the workpiece with high precision, it is not enough to only adjust the thickness of the support member while considering the variation in thickness. That is, when grinding the workpiece, it is necessary to consider the influence of thermal expansion of the workpiece caused by friction. Specifically, the increase in temperature of the grinding wheel and the chuck table that holds the workpiece due to the operating time of the workpiece processing device, and the influence on the workpiece caused by the thermal expansion of various members due to this cannot be ignored. However, the workpiece processing devices of Patent Documents 1 to 3 do not adjust the thickness of the workpiece while considering the thermal influence.

[0009] Furthermore, the workpiece processing device of Patent Document 3 temporarily stops precision grinding of the workpiece to measure the thickness of the workpiece, and adjusts the tilt based on the measured thickness of the workpiece. Since this workpiece processing device temporarily stops precision grinding of the workpiece, it has a problem in terms of workpiece throughput (production volume).

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a workpiece processing device that can adjust the thickness of a workpiece by taking into account variations in thickness of the support member and the thermal effect on the workpiece when processing the workpiece by bonding it to a support member, and can further improve productivity. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention proposes the following means. <1> A workpiece machining apparatus according to one aspect of the present invention includes a workpiece grinding mechanism that grinds a surface of a workpiece stacked on a support member at least at a first machining position and a second machining position in sequence, a chuck table that rotates and holds the workpiece, a chuck table adjustment mechanism that adjusts an inclination angle of the chuck table, an index table that transports the chuck table to the first machining position and the second machining position in sequence, a measurement mechanism that optically and non-contactly measures a thickness of the workpiece after machining, and a control mechanism that adjusts the inclination angle by controlling the chuck table adjustment mechanism based on a measurement value by the measurement mechanism. The measuring mechanism includes a first measuring mechanism which measures the thickness of the workpiece while transporting it from the first processing position to the second processing position after processing at the first processing position is completed, and a second measuring mechanism which measures the thickness of the workpiece while transporting it from the second processing position to another position after processing at the second processing position is completed, and adjusts the inclination angle of the chuck table at the second processing position to adjust the thickness of the workpiece based on the measurement value of the first measuring mechanism, and adds the measurement value of the second measuring mechanism to the adjustment of the inclination angle of the chuck table at the second processing position for a new workpiece to be processed next.

[0012] According to the workpiece processing device, a workpiece stacked on a support member is ground (processed) at a first processing position, and the thickness of the workpiece is measured by a first measurement mechanism while the workpiece is transported from the first processing position to a second processing position. This allows the first measurement mechanism to measure the variation in the support member. Based on this measurement value, the control mechanism adjusts the inclination angle (tilt angle) of the chuck table at the second processing position so that the wafer can be ground into a target shape. Thus, the workpiece can be ground (processed) in a state that takes into account the variation in the thickness of the support member.

[0013] Furthermore, the second measuring mechanism measures the thickness of the workpiece while transporting the workpiece ground at the second processing position from the second processing position to another position. Here, the measured thickness of the workpiece differs (varies) from the target shape of the workpiece due to the thermal effect caused by grinding. The second measuring mechanism measures the variation in the thickness of the workpiece caused by the thermal effect. The control mechanism adds the variation in the thickness of the wafer W caused by the thermal effect measured by the second measuring mechanism 32 as information for adjusting the tilt angle of the chuck table 12 at the fine grinding stage ST4. Therefore, a new workpiece to be processed next can be ground (processed) at the second processing position in a state in which the variation caused by the thermal effect is taken into consideration.

[0014] This allows the thickness of the workpiece to be adjusted taking into consideration the variation in thickness of the support member and the thermal effect on the workpiece when processing the workpiece by bonding it to the support member, and therefore allows the workpiece stacked on the support member to be ground accurately and precisely to match the target shape.

[0015] In addition, the thickness of the workpiece ground at the first processing position can be measured by the first measuring mechanism while the workpiece is being transported from the first processing position to the second processing position. Also, the thickness of the workpiece ground at the second processing position can be measured by the second measuring mechanism while the workpiece is being transported from the second processing position to another position. This makes it possible to improve production volume, for example, by eliminating the need to stop grinding the workpiece to measure the thickness of the workpiece.

[0016] <2> the above <1> In the workpiece machining apparatus according to the present invention, the workpiece grinding mechanism may include a rough grinding unit that roughly grinds the workpiece, a medium grinding unit that medium grinds the workpiece that has been roughly ground, and a fine grinding unit that fine grinds the workpiece that has been medium ground, and the medium grinding unit may perform the medium grinding of the workpiece transported to the first machining position, and the fine grinding unit may perform the fine grinding of the workpiece transported to the second machining position.

[0017] According to the workpiece processing device, the workpiece grinding mechanism is provided with three grinding units, a rough grinding unit, a medium grinding unit, and a fine grinding unit. Furthermore, the workpiece transported to the first processing position is medium ground in the medium grinding unit, and the workpiece transported to the second processing position is fine ground in the fine grinding unit. Therefore, the workpiece can be roughly ground in the rough grinding unit before being medium ground in the medium grinding unit. This allows the workpiece to be medium ground with high precision when being medium ground in the medium grinding unit. Therefore, the workpiece can be ground more precisely and accurately to match the target shape.

[0018] <3> the above <2> In the workpiece machining apparatus according to the present invention, the control mechanism may add the measurement value of the second measuring mechanism to adjust the inclination angle of the chuck table in only the intermediate grinding, or in both the intermediate grinding and the fine grinding, for a new wafer to be machined next.

[0019] According to the above-described workpiece machining device, the results of shape measurement after fine grinding can be selectively reflected in the medium grinding and fine grinding of the next workpiece, allowing the next workpiece to be machined with even greater precision. Effect of the Invention

[0020] According to the present invention, when a workpiece is bonded to a support member and processed, the thickness of the workpiece can be adjusted taking into consideration variations in thickness of the support member and the thermal effect on the workpiece, thereby further improving productivity. [Brief description of the drawings]

[0021] [Figure 1] 1 is a plan view showing a basic configuration of a workpiece machining device according to an embodiment of the present invention. [Diagram 2] 4 is a conceptual diagram illustrating a process of grinding a wafer by the workpiece processing apparatus according to the embodiment. FIG. [Diagram 3] 4 is a cross-sectional view showing a state in which wafers in the laminated wafer according to the embodiment have been roughly ground and medium ground. FIG. [Figure 4] 11 is a cross-sectional view showing a state in which wafers in the laminated wafer according to the embodiment have been precision ground. FIG. [Diagram 5] 11 is a cross-sectional view showing a wafer having a target shape in the laminated wafer according to the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a workpiece machining device according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, when the number, value, amount, range, etc. of components are mentioned, the number is not limited to the specific number, and may be more or less than the specific number, unless otherwise specified or when it is clearly limited to a specific number in principle.

[0023] In addition, when referring to the shape or positional relationship of components, etc., this includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or considered to be clearly different in principle.

[0024] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional ratios of the components may not be the same as the actual ones. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0025] Fig. 1 is a plan view showing the basic configuration of a workpiece processing device. Fig. 2 is a conceptual diagram explaining a process of grinding a wafer by the workpiece processing device. Fig. 3 is a cross-sectional view showing a state in which a wafer in a stacked wafer has been roughly ground and medium ground.

[0026] As shown in FIGS. 1 to 3, the workpiece processing device 1 holds the workpiece W at a predetermined grinding position and grinds the surface Ws of the held workpiece W, thereby precisely grinding the workpiece W into a target shape (target thickness). Here, the thin, plate-like workpiece W is handled by being stacked on a stacking surface SWs of a support member (support wafer) SW. Hereinafter, the workpiece W will be described as a "wafer W." The wafer W may be a silicon wafer, a silicon carbide wafer, or the like, but is not limited to these. Also, a stack in which wafers W are stacked on the stacking surface SWs of the support member SW will be described as a "laminated wafer 100."

[0027] The workpiece machining device 1 includes a holding means 2, a workpiece grinding mechanism 3, a measuring mechanism 4, and a control mechanism 5. The holding means 2 includes an index table 11, a chuck table 12, and a tilt mechanism (chuck table adjustment mechanism) 13 (see FIG. 2). A partition plate 15 is provided above the index table 11. The partition plate 15 is formed in a cross shape.

[0028] The index table 11 is divided by partition plates 15 into four stages at equal intervals: an alignment stage ST1, a rough grinding stage ST2, a medium grinding stage (first machining position) ST3, and a fine grinding stage (second machining position) ST4. The four stages, the alignment stage ST1, the rough grinding stage ST2, the medium grinding stage ST3, and the fine grinding stage ST4, are arranged in this order in a counterclockwise direction on the paper surface of FIG. 1. Hereinafter, the counterclockwise direction on the paper surface of FIG. 1 may simply be referred to as the "counterclockwise direction." The partition plates 15 prevent the machining fluid used in each stage from splashing onto an adjacent stage.

[0029] The index table 11 is supported so as to be rotatable counterclockwise around a rotation shaft 18. The index table 11 is provided with four chuck tables 12. The four chuck tables 12 are provided on the index table 11 so as to be positionable on an alignment stage ST1, a rough grinding stage ST2, a medium grinding stage ST3, and a fine grinding stage ST4. The index table 11 rotates counterclockwise in steps of 90° each time, whereby the chuck table 12 is transported (transferred) counterclockwise to the alignment stage ST1, the rough grinding stage ST2, the medium grinding stage ST3, and the fine grinding stage ST4 in that order.

[0030] The chuck table 12 is disposed so as to be rotatable about a rotation axis O via a tilt mechanism 13 described later. The chuck table 12 is provided with an adsorption body 12a made of porous ceramic embedded on the upper surface. The chuck table 12 adsorbs the laminated wafers 100 placed on the adsorption body 12a with negative pressure. As a result, the center of the laminated wafers 100 is aligned with the rotation axis O of the chuck table 12, and the laminated wafers 100 are vacuum-adsorbed to the adsorption body 12a, so that the laminated wafers 100 are rotated and held together.

[0031] The laminated wafers 100 transported by a transport device (not shown) or the like are sucked and held in a predetermined aligned position on the chuck table 12 of the alignment stage ST1. The laminated wafers 100 sucked and held on the chuck table 12 are transported to the rough grinding stage ST2 by the index table 11 rotating 90° counterclockwise.

[0032] The laminated wafers 100 transported to the rough grinding stage ST2 have their surfaces Ws of the wafers W roughly ground (processed) to a first surface Ws1 by a rough grinding unit 21, which will be described later. The roughly ground laminated wafers 100 are transported to the intermediate grinding stage ST3 by the index table 11 rotating counterclockwise.

[0033] The laminated wafers 100 transported to the intermediate grinding stage ST3 have the surface Ws of the wafer W intermediately ground (processed) to a second surface Ws2 by the intermediate grinding unit 22 described later. The laminated wafers 100 that have been intermediately ground are transported to the fine grinding stage ST4 by the index table 11 rotating 90° counterclockwise.

[0034] The laminated wafers 100 transported to the precision grinding stage ST4 have the surface Ws of the wafer W precision ground (finish processed) to a third surface Ws3 by a precision grinding unit 23 described below. The precision ground laminated wafers 100 are transported to the alignment stage ST1 by the index table 11 rotating 90° counterclockwise. The laminated wafers 100 transported to the alignment stage ST1 are stored in a rack or the like (not shown) from the chuck table 12 by a transport device or the like (not shown).

[0035] The chuck table 12 is equipped 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 in the XY direction (see FIG. 1). Thus, the tilt mechanism 13 can adjust the tilt angle θ of the laminated wafers 100 held on the chuck table 12.

[0036] The workpiece grinding mechanism 3 grinds the surfaces of the laminated wafers 100 held on the chuck table 12 (i.e., the surfaces Ws of the wafers W) in sequence at a rough grinding stage ST2, a medium grinding stage ST3, and a fine grinding stage ST4. The workpiece grinding mechanism 3 grinds the surfaces Ws of the wafers W to thin the wafers W. The workpiece grinding mechanism 3 includes a rough grinding unit 21, a medium grinding unit 22, and a fine grinding unit 23.

[0037] The rough grinding unit 21 includes a rough grinding wheel 21a disposed above the rough grinding stage ST2. The rough grinding wheel 21a is supported by a feed device (not shown) so as to be movable up and down. The rough grinding wheel 21a roughly grinds the front surface Ws of the wafer W in the laminated wafer 100 held on the rough grinding stage ST2.

[0038] The medium grinding unit 22 includes a medium grinding wheel 22a disposed above the medium grinding stage ST3. The medium grinding wheel 22a is supported by a feed device (not shown) so that it can be raised and lowered in the vertical direction. The medium grinding wheel 22a medium grinds the front surface Ws of the wafer W in the laminated wafer 100 disposed on the medium grinding stage ST3.

[0039] The precision grinding unit 23 includes a precision grinding wheel 23a disposed above the precision grinding stage ST4. The precision grinding wheel 23a is supported by a feed device (not shown) so as to be movable up and down. The precision grinding wheel 23a precision-grinds the front surface Ws of the wafer W in the laminated wafers 100 disposed on the precision grinding stage ST4.

[0040] The measuring mechanism 4 optically and non-contactly measures the thickness of the wafer W that has been medium ground by the medium grinding wheel 22a of the medium grinding unit 22, and optically and non-contactly measures the thickness of the wafer W that has been fine ground by the fine grinding wheel 23a of the fine grinding unit 23. The measuring mechanism 4 includes a first measuring mechanism 31 and a second measuring mechanism 32.

[0041] The first measurement mechanism 31 is disposed, for example, at a position corresponding to the partition plate 15 that separates the intermediate grinding stage ST3 and the fine grinding stage ST4. Specifically, the first measurement mechanism 31 is disposed directly above the transfer trajectory of the center of the laminated wafers 100 when the index table 11 transfers the laminated wafers 100 from the intermediate grinding stage ST3 to the fine grinding stage ST4.

[0042] The first measuring mechanism 31 measures the thickness of the wafer W in an optical non-contact manner, and for example, a spectral interference type thickness gauge (NCIG: Non-contact In-process Gauge) is used, but is not limited to this. After intermediate grinding is completed at the intermediate grinding stage ST3, the first measuring mechanism 31 measures the thickness of the wafer W while transporting the laminated wafers 100 from the intermediate grinding stage ST3 to the fine grinding stage ST4.

[0043] The second measurement mechanism 32 is disposed, for example, at a position corresponding to the partition plate 15 that separates the precision grinding stage ST4 and the alignment stage ST1. Specifically, the second measurement mechanism 32 is disposed directly above the transfer trajectory of the center of the laminated wafers 100 when the index table 11 transfers the laminated wafers 100 from the precision grinding stage ST4 to the alignment stage ST1.

[0044] The second measurement mechanism 32 is configured similarly to the first measurement mechanism 31. That is, the second measurement mechanism 32 measures the thickness of the wafer W in an optical non-contact manner, and for example, a spectroscopic interference type thickness gauge (NCIG) is used, but is not limited to this. For example, after precision grinding is completed on the precision grinding stage ST4, the second measurement mechanism 32 measures the thickness of the wafer W while transporting the laminated wafers 100 from the precision grinding stage ST4 to the alignment stage ST1 (another position).

[0045] The control mechanism 5 controls the operation of each of the components constituting the workpiece machining device 1. The control mechanism 5 is composed of, for example, a CPU (Central Processing Unit), a memory, etc. The functions of the control mechanism 5 may be realized by control using software, or may be realized by operation using hardware.

[0046] The control mechanism 5 adjusts the tilt angle θ of the chuck table 12 by controlling the tilt mechanism 13 based on the measurement values ​​by the first measuring mechanism 31 and the second measuring mechanism 32. Specifically, the control mechanism 5 controls the tilt mechanism 13 in the fine grinding stage ST4 based on the measurement value of the first measuring mechanism 31. By controlling the tilt mechanism 13 with the control mechanism 5, the tilt angle θ of the chuck table 12 is adjusted to adjust the thickness of the wafer W. In addition, the control mechanism 5 adds the measurement value of the second measuring mechanism 32 as information for adjusting the tilt angle θ of the chuck table 12 in at least one of the intermediate grinding stage ST3 and the fine grinding stage ST4 for a new wafer W to be processed next. For example, when the shape of the laminated wafers 100 is significantly different from the target shape as a result of the shape measurement of the laminated wafers 100 by the second measuring mechanism 32, the control mechanism 5 preferably adds the measurement value of the second measuring mechanism 32 as information for adjusting the tilt angle θ of the chuck table 12 in the tilt adjustment of only the intermediate grinding stage ST3, or in the tilt adjustment of both the intermediate grinding stage ST3 and the fine grinding stage ST4, for the new wafer W to be processed next. Conventionally, the angle error (tilt error) of the intermediate grinding stage and the fine grinding stage is assembled and adjusted as small as possible, and the remaining small angle error is also adjusted in advance by taking the shape measurement result after intermediate grinding into account in the fine grinding. However, since the influence of grinding heat is different between intermediate grinding and fine grinding, the remaining small angle error varies for each grinding. In this embodiment, the shape measurement result after fine grinding is selectively reflected in the intermediate grinding and fine grinding of the next wafer W, so that processing can be performed with even higher accuracy. In addition, when the deviation between the shape of the laminated wafers 100 and the target shape is small, the control mechanism 5 may add the measurement value of the second measuring mechanism 32 as information for adjusting the inclination angle θ of the chuck table 12 in the tilt adjustment of the precision grinding stage ST4 for the new wafer W to be processed next.

[0047] Next, a procedure for grinding the wafer W by the workpiece processing device 1 will be described with reference to FIGS. Fig. 4 is a cross-sectional view showing a state in which a wafer in the stacked wafers has been precision ground. Fig. 5 is a cross-sectional view showing a wafer in the stacked wafers having a target shape. Hereinafter, the wafer in the target shape shown in Fig. 5 may be referred to as "target wafer TW".

[0048] 1 to 3, the surface Ws of the wafer W is roughly ground to a first surface Ws1 by the rough grinding wheel 21a at the rough grinding stage ST2. After the wafer W is roughly ground, the index table 11 is rotated 90° counterclockwise in the direction of the arrow A. Thus, the laminated wafers 100 are transported from the rough grinding stage ST2 to the intermediate grinding stage ST3.

[0049] After the laminated wafers 100 are transported to the medium grinding stage ST3, the surface Ws of the wafer W is medium-ground to a second surface Ws2 by the medium grinding wheel 22a at the medium grinding stage ST3. After the wafer W is medium-ground, the index table 11 is rotated 90° counterclockwise in the direction of arrow A. Thus, the laminated wafers 100 are transported from the medium grinding stage ST3 to the fine grinding stage ST4.

[0050] During the transfer from the intermediate grinding stage ST3 to the fine grinding stage ST4, the center of the laminated wafers 100 passes directly below the first measuring mechanism 31 while rotating about the rotation axis O. When the laminated wafers 100 pass directly below while rotating about the rotation axis O, the first measuring mechanism 31 can expand the measurement points to the entire surface including the center of the wafer W. Therefore, the thickness of the entire surface of the wafer W can be measured by the first measuring mechanism 31. Also, the thickness variation in the support member SW can be measured over the entire area of ​​the support member SW. This makes it possible to measure the thickness of the wafer W taking into account the thickness variation in the support member SW.

[0051] Based on the variation in thickness of the support member SW, the control mechanism 5 adjusts the tilt angle θ of the chuck table 12 by controlling the tilt mechanism 13 in the precision grinding stage ST4. Specifically, the tilt angle θ of the chuck table 12 is adjusted by controlling the tilt mechanism 13 so that the wafer W transferred to the precision grinding stage ST4 can be ground into a target shape of the target wafer TW (see FIG. 5).

[0052] The measurement point of the first measuring mechanism 31 can be arbitrarily adjusted by the transport speed of the index table 11 and the rotation speed of the chuck table 12 (i.e., the laminated wafers 100). For example, by increasing the rotation speed of the chuck table 12, the number of times that the measurement point of the first measuring mechanism 31 is scanned in the radial direction of the wafer W can be increased.

[0053] 1, 2, 4, and 5, in a state in which the inclination angle θ of the chuck table 12 is adjusted in the precision grinding stage ST4, the surface Ws of the wafer W is precision ground to the third surface Ws3 by the precision grinding wheel 23a. This allows the surface Ws of the wafer W to be precision ground along the stacking surface SWs of the support member SW. Here, the precision grinding of the wafer W causes a thermal effect on the wafer W. As a result, the precision ground wafer W has a difference (variation) in thickness compared to the target wafer TW. After the wafers W are precision ground, the index table 11 is rotated counterclockwise by 90 degrees in the direction of the arrow A. Thus, the laminated wafers 100 are transferred from the precision grinding stage ST4 to the alignment stage ST1.

[0054] While the laminated wafers 100 are being transferred from the precision grinding stage ST4 to the alignment stage ST1, the center of the laminated wafers 100 passes directly below the second measurement mechanism 32 while rotating about the rotation axis O. Similar to the first measurement mechanism 31, the second measurement mechanism 32 can expand the measurement point to the entire surface including the center of the wafer W when the laminated wafers 100 pass directly below while rotating about the rotation axis O. Therefore, the thickness of the entire surface of the wafer W can be measured by the second measurement mechanism 32. This makes it possible to measure the difference (variation) in thickness from the target wafer TW caused by thermal effects based on the thickness of the entire surface of the wafer W.

[0055] The measurement point of the second measuring mechanism 32 can be arbitrarily adjusted by the transport speed of the index table 11 and the rotation speed of the chuck table 12 (i.e., the laminated wafers 100), similarly to the first measuring mechanism 31. For example, by increasing the rotation speed of the chuck table 12, the number of times that the measurement point of the first measuring mechanism 31 is scanned in the radial direction of the wafer W can be increased.

[0056] The control mechanism 5 adds the thickness variation relative to the target wafer TW as information for adjusting the tilt angle θ of the chuck table 12 in the precision grinding stage ST4 for the next new wafer W to be processed. In other words, taking into consideration the thickness variation of the wafer W relative to the target wafer TW caused by thermal effects, the tilt angle θ of the chuck table 12 in the precision grinding stage ST4 is readjusted (adjusted) so that the wafer W can be ground to the target shape.

[0057] With the inclination angle θ of the chuck table 12 in the precision grinding stage ST4 readjusted, a new wafer W to be processed next is precision ground. Thus, the thickness of the new wafer W to be processed next can be adjusted taking into consideration the variation in thickness of the support member SW and the thermal effect on the wafer W. This allows the new wafer W to be processed next, which is stacked on the support member SW, to be precisely ground to match the target shape (see FIG. 5) with high precision.

[0058] 1 to 3, according to the workpiece processing apparatus 1 described above, the wafers W of the laminated wafers 100 are medium-ground to the second surface Ws2 on the medium-grinding stage ST3. While the medium-ground laminated wafers 100 are being transported from the medium-grinding stage ST3 to the fine grinding stage ST4, the thickness of the wafers W is measured by the first measuring mechanism 31. This allows the first measuring mechanism 31 to measure the variation in the support members SW. Based on the measured thickness of the wafer W and the variations in the support members SW, the inclination angle θ of the chuck table 12 in the precision grinding stage ST4 is adjusted so that the wafer W can be precision ground into the target shape of the target wafer TW (see FIG. 5). Thus, in the precision grinding stage ST4, the wafer W can be precision ground in a state in which the variations in the thickness of the support members SW are taken into consideration.

[0059] 1, 2 and 4, the wafer W ground on the precision grinding stage ST4 is transported from the precision grinding stage ST4 to the alignment stage ST1, while the thickness of the wafer W is measured by the second measurement mechanism 32. Here, a difference (variation) occurs in the measured thickness of the wafer W with respect to the target wafer TW (see FIG. 5) due to the thermal effect caused by the precision grinding. The variation in thickness of the wafer W caused by thermal influence is measured by the second measurement mechanism 32. The variation in thickness of the wafer W caused by thermal influence measured by the second measurement mechanism 32 is added as information for adjusting the tilt angle θ of the chuck table 12 in the precision grinding stage ST4. Thus, a new wafer W to be processed next can be precision ground in the precision grinding stage ST4 in a state in which the variation caused by thermal influence is taken into consideration.

[0060] As a result, when processing the wafers W as laminated wafers 100 bonded to the support members SW, the thickness of the wafers W can be adjusted taking into consideration the variation in thickness of the support members SW and the thermal effect on the wafers W. Therefore, the wafers W laminated on the support members SW can be accurately ground to match the target shape of the target wafer TW (see FIG. 5) with high precision.

[0061] 1 and 2, the thickness of the wafer W that has been medium ground at the medium grinding stage ST3 can be measured by the first measurement mechanism 31 while the wafer W is being transported from the medium grinding stage ST3 to the fine grinding stage ST4. Also, the thickness of the wafer W that has been fine ground at the fine grinding stage ST4 can be measured by the second measurement mechanism 32 while the wafer W that has been fine ground is being transported from the fine grinding stage ST4 to the alignment stage ST1. This makes it possible to improve production volume, for example, by eliminating the need to stop grinding of the wafer W to measure the thickness of the wafer W.

[0062] Furthermore, the workpiece grinding mechanism 3 includes three grinding units, a rough grinding unit 21, a medium grinding unit 22, and a fine grinding unit 23. Therefore, the wafer W can be roughly ground in the rough grinding unit 21 before being medium ground in the medium grinding unit 22. This allows the wafer W to be medium ground with high precision when being medium ground in the medium grinding unit 22. Therefore, the wafer W can be ground more precisely and accurately to match the target shape.

[0063] 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 spirit of the present invention. For example, in the above embodiment, the workpiece grinding mechanism 3 is provided with three grinding units, i.e., the rough grinding unit 21, the medium grinding unit 22, and the fine grinding unit 23, and the wafer W is ground in stages at the three grinding stages ST2, ST3, and ST4. However, the present invention is not limited to this. As another example, the workpiece grinding mechanism 3 may be provided with two grinding units, and the wafer W may be ground in stages at the two grinding stages. Furthermore, the finishing process may be polishing with an abrasive cloth, and the wafer W may be processed in stages in the order of rough grinding, fine grinding, and polishing.

[0064] Furthermore, in the above-described embodiment, the first measuring mechanism 31 is arranged at a position corresponding to the partition plate 15 that separates the medium grinding stage ST3 and the fine grinding stage ST4, but it may also be arranged at a position corresponding to the partition plate 15 that separates the rough grinding stage ST2 and the medium grinding stage ST3.

[0065] In addition, the components in this embodiment can be replaced with well-known components as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0066] 1 Workpiece processing equipment 2 Holding means 3 Workpiece grinding mechanism 4 Measuring mechanism 5 Control Mechanism 11 Index Table 12 Chuck table 13 Tilt mechanism (chuck table adjustment mechanism) 21 Rough grinding section 22 Medium grinding section 23 Precision grinding department 31 First measurement mechanism 32 Second measurement mechanism ST2 Rough grinding stage ST3 Medium grinding stage (first processing position) ST4 Precision grinding stage (second processing position) SW support material W Wafer (work) Ws Wafer surface Ws1 first surface Ws2 second surface Ws3 third surface θ Tilt angle

Claims

1. a workpiece grinding mechanism that sequentially grinds a surface of a workpiece stacked on a support member at least at a first processing position and a second processing position; A chuck table that rotates and holds the workpiece; a chuck table adjustment mechanism for adjusting an inclination angle of the chuck table; an index table that sequentially transports the chuck table to the first processing position and the second processing position; A measuring mechanism for optically measuring the thickness of the workpiece after machining in a non-contact manner; a control mechanism for adjusting the tilt angle by controlling the chuck table adjustment mechanism based on the measurement value by the measurement mechanism, The measuring mechanism includes: a first measuring mechanism that measures a thickness of the workpiece while transporting the workpiece from the first processing position to the second processing position after the processing at the first processing position is completed; a second measuring mechanism for measuring a thickness of the workpiece while transporting the workpiece from the second processing position to another position after processing at the second processing position is completed; adjusting a tilt angle of the chuck table at the second processing position to adjust a thickness of the workpiece based on a measurement value of the first measuring mechanism; adding the measurement value of the second measuring mechanism to an adjustment of the tilt angle of the chuck table at the second processing position for a new workpiece to be processed next; A workpiece machining device characterized by the above.

2. The workpiece grinding mechanism includes: A rough grinding unit that roughly grinds the workpiece, a medium grinding unit that medium grinds the workpiece that has been roughly ground, and a fine grinding unit that fine grinds the workpiece that has been medium ground, The medium grinding unit performs the medium grinding on the workpiece transported to the first processing position, The precision grinding unit performs precision grinding on the workpiece transported to the second processing position.

2. The workpiece machining apparatus according to claim 1 .

3. 3. The workpiece processing device according to claim 2, wherein the control mechanism adds the measurement value of the second measuring mechanism to adjustment of a tilt angle of a chuck table in only the intermediate grinding or in both the intermediate grinding and the fine grinding for a new wafer to be processed next.

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