Processing method and processing device

Abstract

To properly improve the flatness of a substrate subjected to grinding.SOLUTION: A processing method for a substrate in a processing device includes steps of: holding a substrate on a substrate holding part; a finish-grinding unit performing a finish grinding process of the substrate held on the substrate holding part; measuring a distribution of finished thicknesses of the substrate; and determining a relative inclination between the substrate holding part and the finish grinding unit, on the basis of the measured distribution of finished thicknesses. After the steps, the relative inclination between the substrate holding part and the finish grinding unit is adjusted, and the finish grinding unit grinds a subsequent substrate to be ground held on the substrate holding part.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a processing method and a processing apparatus.

Background Art

[0002] Patent Document 1 discloses a wafer grinding apparatus including a wafer grinding means, an inclination adjusting means for adjusting the inclination of the rotation axis of the grinding means, and a grinding condition storage means for storing the grinding conditions of the wafer. According to the grinding apparatus described in Patent Document 1, by adjusting the inclination of the rotation axis of the grinding means based on the information stored in the grinding condition storage means, the variation in the thickness of the wafer is minimized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure appropriately improves the flatness of the substrate after the grinding process.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a method for processing a substrate in a processing apparatus, including holding the substrate in a substrate holding unit, performing a finish grinding process on the substrate held in the substrate holding unit using a finish grinding unit, measuring the finish thickness distribution of the substrate, determining the relative inclination between the substrate holding unit and the finish grinding unit based on the measured thickness distribution, and then adjusting the relative inclination between the substrate holding unit and the finish grinding unit to grind the next substrate to be ground held in the substrate holding unit using the finish grinding unit.

Advantages of the Invention

[0006] According to the present disclosure, the flatness of the substrate after grinding can be appropriately improved.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0008] In recent years, in the manufacturing process of semiconductor devices, with respect to a stacked substrate in which a semiconductor substrate (hereinafter referred to as "first substrate") having devices such as a plurality of electronic circuits formed on its surface and a second substrate are joined, the back surface of the first substrate is ground and thinned.

[0009] The thinning of the first substrate is performed by bringing a grinding wheel into contact with the back surface of the first substrate and grinding it while the back surface of the second substrate is held by a substrate holding portion. However, when grinding the first substrate in this manner, due to the relative inclination between the grinding wheel that contacts the back surface of the first substrate and the substrate holding surface that holds the second substrate, the flatness (TTV: Total Thickness Variation) of the first substrate after grinding may deteriorate. Specifically, for example, when the processing apparatus temporarily enters a standby state due to the replacement of the grinding wheel for grinding the first substrate, or when the grinding conditions in the processing apparatus are changed, before and after the standby of such a processing apparatus, before and after the change of the grinding conditions, due to changes in the apparatus characteristics and environmental characteristics (for example, changes in the apparatus temperature and the ambient temperature, changes in the surface state of the grinding wheel, etc.), the parallelism between the grinding wheel and the substrate holding surface changes. As a result, when the grinding process immediately after returning from the standby state is performed under the same conditions as the grinding process before the standby, since the parallelism between the grinding wheel and the substrate holding surface has changed, there is a risk that the TTV of the first substrate deteriorates.

[0010] The processing method described in Patent Document 1 mentioned above is a grinding apparatus for grinding the first substrate (wafer) to a uniform thickness by adjusting the inclination of the rotation axis of the grinding wheel (grinding means). However, Patent Document 1 does not have any description regarding considering the apparatus characteristics and environmental characteristics before and after the standby state of the processing apparatus as described above. Further, in the method described in Patent Document 1, it is necessary to grind a substrate (for example, a dummy wafer) for adjusting the inclination of the rotation axis of the grinding wheel (grinding means). In addition to taking time for adjusting the inclination of the rotation axis, it is necessary to discard the substrate used for the inclination adjustment. Thus, there is room for improvement in the conventional grinding process of the substrate.

[0011] Therefore, the technology according to the present disclosure appropriately improves the flatness of the substrate after grinding. Specifically, particularly after the processing apparatus returns from the standby state or after the grinding conditions are changed, the flatness of the first substrate held by the substrate holding unit is appropriately improved. Hereinafter, the processing apparatus and the processing method according to the present embodiment will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0012] In the processing apparatus 1 according to the present embodiment described below, as shown in FIG. 1, processing is performed on a laminated wafer T as a laminated substrate in which a first wafer W as a first substrate and a second wafer S as a second substrate are joined. Then, in the processing apparatus 1, the first wafer W is thinned. Hereinafter, in the first wafer W, the surface on the side joined to the second wafer S is referred to as the front surface Wa, and the surface on the side opposite to the front surface Wa is referred to as the back surface Wb. Similarly, in the second wafer S, the surface on the side joined to the first wafer W is referred to as the front surface Sa, and the surface on the side opposite to the front surface Sa is referred to as the back surface Sb.

[0013] The first wafer W is, for example, a semiconductor wafer such as a silicon substrate, and a device layer D including a plurality of devices is formed on the front surface Wa. A surface film Fw is further formed on the device layer D, and the surface film Fw is joined to the second wafer S through the surface film Fw. Examples of the surface film Fw include an oxide film (SiO 2 film, TEOS film), SiC film, SiCN film, or an adhesive.

[0014] The second wafer S is, for example, a wafer that supports the first wafer W. A surface film Fs is formed on the front surface Sa of the second wafer S, and the peripheral portion is chamfered. Examples of the surface film Fs include an oxide film (SiO 2Examples include a film (such as a TEOS film), a SiC film, a SiCN film, or an adhesive. Further, the second wafer S functions as a protective material (support wafer) that protects the device layer D of the first wafer W. Note that the second wafer S does not necessarily have to be a support wafer and may be a device wafer on which a device layer is formed in the same manner as the first wafer W. In such a case, a surface film Fs is formed on the surface Sa of the second wafer S via the device layer.

[0015] In the drawings used in the following description, for the sake of avoiding complexity in illustration, the illustration of the device layer D and the surface films Fw and Fs may be omitted.

[0016] As shown in FIG. 2, the processing apparatus 1 has a configuration in which a loading / unloading station 2 and a processing station 3 are integrally connected. In the loading / unloading station 2, for example, a cassette Ct capable of accommodating a plurality of polymerization wafers T is loaded and unloaded to and from the outside. The processing station 3 is provided with various processing apparatuses for performing desired processing on the polymerization wafer T.

[0017] The loading / unloading station 2 is provided with a cassette mounting table 10. In the illustrated example, a plurality of, for example, four cassettes Ct can be mounted on the cassette mounting table 10 in a row in the X-axis direction. Note that the number of cassettes Ct mounted on the cassette mounting table 10 is not limited to the present embodiment and can be arbitrarily determined.

[0018] The loading / unloading station 2 is provided with a wafer transfer region 20 adjacent to the cassette mounting table 10 on the positive Y-axis side of the cassette mounting table 10. The wafer transfer region 20 is provided with a wafer transfer device 22 configured to be movable on a transfer path 21 extending in the X-axis direction.

[0019] The wafer transfer device 22 has a transfer fork 23 that holds and transfers the polymer wafer T before and after the grinding process. The tip of the transfer fork 23 branches into two, and adsorbs and holds the polymer wafer T. Further, the transfer fork 23 is configured to be movable in the horizontal direction, the vertical direction, around the horizontal axis, and around the vertical axis. Note that the configuration of the wafer transfer device 22 is not limited to this embodiment, and any configuration can be adopted. And the wafer transfer device 22 is configured to be able to transfer the polymer wafer T to the cassette Ct of the cassette mounting table 10, the alignment unit 50, and the first cleaning unit 60.

[0020] In the processing station 3, processing such as grinding and cleaning is performed on the polymer wafer T. The processing station 3 includes a transfer unit 30 that transfers the polymer wafer T, a grinding unit 40 that performs grinding processing on the first wafer W, an alignment unit 50 that adjusts the horizontal orientation of the polymer wafer T before the grinding process, a first cleaning unit 60 that spin-cleans the first wafer W after the grinding process, and a second cleaning unit 70 that cleans the back surface Sb of the second wafer S after the grinding process.

[0021] The transfer unit 30 is an articulated robot including a plurality of, for example, three arms 31. Each of the three arms 31 is configured to be rotatable. A transfer pad 32 that adsorbs and holds the polymer wafer T is attached to the tip arm 31. Further, the base end arm 31 is attached to a lifting mechanism 33 that raises and lowers the arm 31 in the vertical direction. Note that the configuration of the transfer unit 30 is not limited to this embodiment, and any configuration can be adopted. And the transfer unit 30 is configured to be able to transfer the polymer wafer T to the delivery position A0 (described later) of the grinding unit 40, the alignment unit 50, the first cleaning unit 60, and the second cleaning unit 70.

[0022] The grinding unit 40 is provided with a rotary table 41. On the rotary table 41, four chucks 42 for sucking and holding the polymerized wafer T are provided. By the rotation of the rotary table 41, the four chucks 42 can be moved to the delivery position A0 and the processing positions A1 to A3. Further, each of the four chucks 42 is configured to be rotatable about a vertical axis by a rotation mechanism (not shown).

[0023] At the delivery position A0, the transfer unit 30 transfers the polymerized wafer T. At the processing position A1, a rough grinding unit 80 is arranged to rough grind the first wafer W. At the processing position A2, a medium grinding unit 90 is arranged to medium grind the first wafer W. At the processing position A3, a finish grinding unit 100 is arranged to finish grind the first wafer W.

[0024] For example, a porous chuck is used for the chuck 42 to suck and hold the back surface Sb of the second wafer S forming the polymerized wafer T. The surface of the chuck 42, that is, the holding surface of the polymerized wafer T, has a convex shape in which the central portion protrudes more than the end portions in a side view. Since the protrusion of this central portion is minute, the convex shape of the chuck 42 is omitted in the drawing.

[0025] As shown in FIG. 3, the chuck 42 is held by a chuck base 43. The chuck base 43 is provided with an inclination adjustment unit 44 for adjusting the inclination of the chuck 42 and the chuck base 43 in the horizontal direction. The inclination adjustment unit 44 has a fixed shaft 45 and a plurality of lifting shafts 46 provided on the lower surface of the chuck base 43. Each lifting shaft 46 is configured to be extendable and retractable to lift and lower the chuck base 43. By this inclination adjustment unit 44, with one end of the outer peripheral portion of the chuck base 43 (the position corresponding to the fixed shaft 45) as a base point, the other end is lifted and lowered in the vertical direction by the lifting shafts 46, so that the chuck 42 and the chuck base 43 can be inclined. Thereby, the relative inclination between the various grinding units at the processing positions A1 to A3 and the chuck 42, that is, the inclination of the back surface Wb of the first wafer W with respect to the grinding wheel provided in the various grinding units can be adjusted.

[0026] Note that the configuration of the inclination adjustment unit 44 is not limited to this, and it can be arbitrarily selected as long as the relative angle (parallelism) of the first wafer W with respect to the grinding wheel can be adjusted.

[0027] As shown in FIG. 3, the rough grinding unit 80 as the rough grinding processing unit or the first grinding unit includes a rough grinding wheel 81 having an annular rough grinding wheel on the lower surface, a mount 82 that supports the rough grinding wheel 81, a spindle 83 that rotates the rough grinding wheel 81 via the mount 82, and a drive unit 84 that incorporates, for example, a motor (not shown). The rough grinding unit 80 is configured to be movable in the vertical and horizontal directions along the support column 85 shown in FIG. 2. In the rough grinding unit 80, with a part of the arc of the annular rough grinding wheel in contact with the first wafer W of the polymerized wafer T held by the chuck 42, the chuck 42 and the rough grinding wheel 81 are rotated respectively, thereby rough grinding the back surface Wb of the first wafer W.

[0028] As shown in FIGS. 2 and 3, the semi-finishing grinding unit 90 as the first grinding unit has the same configuration as the rough grinding unit 80. That is, the semi-finishing grinding unit 90 includes a semi-finishing grinding wheel 91 having an annular semi-finishing grinding wheel, a mount 92, a spindle 93, a drive unit 94, and a support column 95. Note that the grain size of the abrasive grains of the semi-finishing grinding wheel is smaller than the grain size of the abrasive grains of the rough grinding wheel.

[0029] As shown in FIGS. 2 and 3, the finish grinding unit 100 as the second grinding unit has the same configuration as the rough grinding unit 80 and the semi-finishing grinding unit 90. That is, the finish grinding unit 100 includes a finish grinding wheel 101 having an annular finish grinding wheel, a mount 102, a spindle 103, a drive unit 104, and a support column 105. Note that the grain size of the abrasive grains of the finish grinding wheel is smaller than the grain size of the abrasive grains of the semi-finishing grinding wheel.

[0030] The processing station 3 is also provided with a thickness measurement unit 110 as a thickness distribution measurement unit that measures the thickness of the first wafer W after the grinding process by the finish grinding unit 100. The thickness measurement unit 110 is provided, for example, at the processing position A3 or the delivery position A0. The thickness measurement unit 110 has, for example, a non-contact sensor (not shown) and a calculation unit (not shown). In the thickness measurement unit 110, the thickness distribution of the first wafer W is obtained from the measurement results (thickness of the first wafer W) at a plurality of points by the sensor, and the TTV data of the first wafer W is calculated.

[0031] As shown in FIG. 2, the above-described processing apparatus 1 is provided with a control unit 120. The control unit 120 is a computer including, for example, a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the polymerized wafer T in the processing apparatus 1. Further, the program storage unit also stores a program for controlling the operations of the drive systems of the above-described various processing units and transfer devices, etc., to realize the processing described later in the processing apparatus 1. Note that the above program may be recorded on a computer-readable storage medium H and installed from the storage medium H to the control unit 120.

[0032] Next, a processing method performed using the processing apparatus 1 configured as described above will be described. In the present embodiment, the first wafer W and the second wafer S are joined in a bonding apparatus (not shown) outside the processing apparatus 1, and a polymerized wafer T is formed in advance.

[0033] First, a cassette Ct containing a plurality of polymerized wafers T is placed on the cassette mounting table 10 of the loading / unloading station 2. Next, the first polymerized wafer T is taken out from the cassette Ct by the transfer fork 23 of the wafer transfer device 22 and transferred to the alignment unit 50 of the processing station 3. In the alignment unit 50, the horizontal orientation of the polymerized wafer T is adjusted by adjusting the position of a notch portion (not shown) formed in the first wafer W (step P1 in FIG. 5).

[0034] The polymerized wafer T with its horizontal orientation adjusted is then conveyed from the alignment unit 50 by the conveyance unit 30 and delivered to the chuck 42 at the delivery position A0 as shown in Fig. 4(a). Subsequently, the rotary table 41 is rotated to sequentially move the chuck 42 to the machining positions A1 to A3.

[0035] At the machining position A1, the back surface Wb of the first wafer W is roughly ground by the rough grinding unit 80 (step P2 in Fig. 5). At the machining position A2, the back surface Wb of the first wafer W is semi-finished ground by the semi-finishing grinding unit 90 (step P3 in Fig. 5). Further, at the machining position A3, the back surface Wb of the first wafer W is finish ground by the finish grinding unit 100 (step P4 in Fig. 5).

[0036] Here, in the finish grinding of step P4, for example, due to device characteristics such as wear of the finish grinding wheel and temperature of the grinding unit 40, or environmental characteristics such as the ambient temperature of the processing apparatus 1, the parallelism between the finish grinding unit 100 and the chuck 42 may deteriorate. In particular, when the polymerized wafer T on which the grinding process is performed is the first polymerized wafer T immediately after the processing apparatus 1 resumes from the standby state or immediately after the grinding conditions are changed, there is a risk that the parallelism may change significantly from the state before the standby of the processing apparatus 1 as described above. And if the first wafer W is finish ground to the final finish thickness in such a state where the parallelism between the finish grinding unit 100 and the chuck 42 has deteriorated, as shown in Fig. 6, the flatness (TTV) of the first wafer W1 after the finish grinding process may deteriorate.

[0037] Therefore, in the processing method according to the present embodiment, in the grinding process of the first polymerized wafer T by the finish grinding unit 100 in step P4, as shown in Fig. 4(b), the thickness of the first wafer W is not allowed to reach the final finish thickness H, and then, by further re-grinding the first wafer W, the TTV of the first wafer W is improved.

[0038] Specifically, first, as shown in FIG. 4(c), the thickness distribution of the first wafer W after the grinding process in step P4 is obtained by measuring the thickness of the first wafer W at a plurality of points by the thickness measurement unit 110, and the TTV data is calculated from the thickness distribution (step P5 in FIG. 5). The calculated TTV data is output to the control unit 120.

[0039] When the TTV data of the first wafer W is calculated, subsequently, the rotation table 41 is rotated to sequentially move the chuck 42 to the machining positions A2 and A3.

[0040] At the machining position A2, the back surface Wb of the first wafer W is re-ground (intermediate grinding) by the intermediate grinding unit 90 (step P6 in FIG. 5). Note that the re-grinding of the first wafer W by the intermediate grinding unit 90 is performed under the same conditions as the first intermediate grinding of the first wafer W in step P3. Specifically, the re-grinding by the intermediate grinding unit 90 is performed without changing the relative inclination between the intermediate grinding unit 90 and the chuck 42.

[0041] When the re-grinding of the first wafer W by the intermediate grinding unit 90 is performed, next, as shown in FIG. 4(d), based on the TTV data of the first wafer W calculated in step P5, the relative inclination between the chuck 42 and the finish grinding unit 100 is adjusted (step P7 in FIG. 5). Specifically, the grinding amount is increased at the position where the thickness is determined to be large in the thickness distribution of the first wafer W and decreased at the position where the thickness is determined to be small so that the in-plane thickness of the first wafer W1 after re-grinding in the finish grinding unit 100 becomes uniform. That is, based on the thickness distribution of the first wafer W, the relative inclination between the chuck 42 and the finish grinding unit 100 is adjusted, thereby adjusting the re-grinding amount of the first wafer W by the finish grinding unit 100.

[0042] When the relative inclination between the finish grinding unit 100 and the chuck 42 is adjusted, at the machining position A3, as shown in FIG. 4(e), the back surface Wb of the first wafer W is re-ground (finish ground) to the final finish thickness H by the finish grinding unit 100 (step P8 in FIG. 5).

[0043] In the present embodiment, before the first wafer W is formed to the final finish thickness in this way, the thickness distribution of the first wafer W is acquired, and further TTV data is calculated. Then, based on this, the relative inclination between the finish grinding unit 100 and the chuck 42 is adjusted. And since the first wafer W is re-ground after the relative inclination is adjusted in this way, even when, for example, the parallelism between the finish grinding unit 100 and the chuck 42 is deteriorated, it is possible to appropriately suppress the deterioration of the TTV of the first wafer W. And in order to improve the TTV of the bonded wafer T based on the thickness distribution of the first wafer W to be ground in this way, it is not necessary to previously grind an inclination adjustment wafer (for example, a dummy wafer), that is, it is not necessary to discard the inclination adjustment wafer as in the conventional case.

[0044] When the first wafer W is formed to the final finish thickness by re-grinding (finish grinding), subsequently, the thickness of the first wafer W after the re-grinding process in step P8 is measured at a plurality of points by the thickness measurement unit 110, thereby acquiring the final finish thickness distribution of the first wafer W, and calculating TTV data from the final finish thickness distribution (step P9 in FIG. 5). The calculated TTV data is output to the control unit 120.

[0045] The bonded wafer T for which the TTV data has been calculated is transported from the delivery position A0 to the second cleaning unit 70 by the transport unit 30, and the back surface Sb of the second wafer S is cleaned and dried while being held by the transport pad 32 (step P10 in FIG. 5).

[0046] Next, the bonded wafer T is transported from the second cleaning unit 70 to the first cleaning unit 60 by the transport unit 30, and the back surface Wb of the first wafer W is finish cleaned using a cleaning liquid nozzle (not shown) (step P11 in FIG. 5).

[0047] After that, the polymerized wafer T on which all processes have been performed is transported to the cassette Ct on the cassette mounting table 10 by the transport fork 23 of the wafer transport device 22. Then, when the first polymerized wafer T is carried into the cassette Ct, subsequently, the processes in the processing device 1 are performed on the second and subsequent polymerized wafers T accommodated in the cassette Ct.

[0048] The processes for the second and subsequent, the nth (n is a natural number of 2 or more) polymerized wafers T in the processing device 1 are sequentially performed by the alignment unit 50, the grinding unit 40, the second cleaning unit 70, and the first cleaning unit 60.

[0049] Here, in the grinding process of the first polymerized wafer T in the grinding unit 40, in order to consider the influence of the deterioration of the parallelism before and after the standby state of the processing device 1 as described above, based on the obtained thickness distribution of the first wafer W, a re-grinding process (steps P5 to P8 in FIG. 5) was performed. However, in the grinding process of the nth polymerized wafer T in the processing device 1, since the parallelism between the finish grinding unit 100 and the chuck 42 has been adjusted by the grinding process of the first polymerized wafer T, it is not necessary to perform the re-grinding process of the first wafer W.

[0050] Therefore, in the grinding process for the nth polymerized wafer T, the re-grinding process (steps P5 to P8 in FIG. 5) for the polymerized wafer T is not performed, and only feedback control based on the final finish thickness distribution obtained in step P9 of FIG. 5 is performed.

[0051] Specifically, the nth polymerized wafer T carried out from the cassette Ct is first adjusted in the horizontal direction in the alignment unit 50 (step Q1 in FIG. 7).

[0052] The polymerized wafer T with its horizontal orientation adjusted is then delivered by the transfer unit 30 from the alignment unit 50 to the chuck 42 at the delivery position A0. Subsequently, the rotary table 41 is rotated to sequentially move the chuck 42 to the processing positions A1 to A3.

[0053] At the processing position A1, the back surface Wb of the first wafer W is roughly ground by the rough grinding unit 80 (step Q2 in FIG. 7). At the processing position A2, the back surface Wb of the first wafer W is semi-finished ground by the semi-finishing grinding unit 90 (step Q3 in FIG. 7).

[0054] When the semi-finishing grinding process is performed on the polymerized wafer T, next, based on the thickness distribution of the first first wafer W obtained in step P9 of FIG. 5, the relative inclination between the chuck 42 and the finish grinding unit 100 is adjusted (step Q4 in FIG. 7). Thereby, the change in the parallelism between the finish grinding unit 100 and the chuck 42 due to the change in the apparatus characteristics (e.g., wear of the grinding wheel and apparatus temperature) and environmental characteristics (e.g., ambient temperature) during the finish grinding of the first polymerized wafer T is adjusted, that is, the result of the finish grinding process of the first polymerized wafer T is fed back to the finish grinding process of the nth polymerized wafer T.

[0055] And when the relative inclination between the finish grinding unit 100 and the chuck 42 is adjusted, at the processing position A3, the first wafer W is finish ground to the final finish thickness (step Q5 in FIG. 7).

[0056] Thereafter, after the TTV data is calculated from the thickness distribution obtained by the thickness measurement unit 110 for the polymerized wafer T subjected to the finish grinding process (step Q6 in FIG. 7), cleaning by the second cleaning unit 70 (step Q7 in FIG. 7) and cleaning by the first cleaning unit 60 (step Q8 in FIG. 7) are sequentially performed, and it is accommodated in the cassette Ct. And when the processing for all the polymerized wafers T accommodated in the cassette Ct is completed, a series of processing in the processing apparatus 1 is completed.

[0057] Note that the adjustment of the relative inclination between the chuck 42 and the finish grinding unit 100 in step Q4 may be performed based on the final finish thickness distribution of the m-th polymerized wafer T (m is a natural number of 1 or more and n - 1 or less) obtained in step Q6, instead of the final finish thickness distribution of the first polymerized wafer T as described above. That is, it may be performed based on the final finish thickness distribution of the polymerized wafer T processed before at least the n-th polymerized wafer T.

[0058] In the above embodiments, the processing of the polymerized wafer T in the processing apparatus 1 has been described by taking the case where the processing of the polymerized wafer T is performed one by one, that is, the processing of another polymerized wafer T is started after the processing of one polymerized wafer T is completed. However, the processing of a plurality of polymerized wafers T may be continuous, that is, the processing of a plurality of polymerized wafers T may be performed simultaneously.

[0059] Note that when the grinding unit 40 includes a plurality (four in this embodiment) of chucks 42 as in the processing apparatus 1 according to the present embodiment, the plurality of chucks 42 are independently deformed and the parallelism deteriorates when the processing apparatus 1 is in the standby state. For this reason, it is desirable that the adjustment of the relative inclination between the finish grinding unit 100 and the chuck 42 according to the present embodiment and the regrinding process (steps P5 to P8 in FIG. 5) be performed in the processing of the first polymerized wafer T held by each of the chucks 42 after the return from the standby state of the processing apparatus 1.

[0060] As described above, according to the processing method according to the present embodiment, in the processing of the first polymerized wafer T held by each chuck 42 immediately after the return from the standby state of the processing apparatus 1, the thickness distribution before the first wafer W is formed to the final finish thickness is acquired, and the inclination of the chuck 42 is adjusted based on this. Then, since the regrinding process of the first wafer W is performed in a state where the inclination of the chuck 42 is adjusted in this way, even when the parallelism between the finish grinding unit 100 and the chuck 42 deteriorates due to the standby of the processing apparatus 1, the TTV of the first wafer W can be appropriately improved.

[0061] In addition, in order to improve the TTV of the first wafer W to be ground based on the thickness distribution before the final finishing thickness of the first wafer W to be ground is formed in this way, it is not necessary to previously grind an inclination adjustment wafer (for example, a dummy wafer), and it is possible to appropriately suppress the occurrence of waste of the inclination adjustment wafer as in the prior art.

[0062] In addition, in the re-grinding process of the first wafer W in the present embodiment, the re-grinding process is performed by two grinding units, that is, an intermediate grinding unit 90 and a finishing grinding unit 100. Here, for example, when the re-grinding process is performed only by the finishing grinding unit 100, the state of the first wafer W at the start of the first grinding process and the second grinding process (re-grinding process) performed by the finishing grinding unit 100 changes. Specifically, in the first grinding process, the grinding process by the finishing grinding unit 100 is performed after the intermediate grinding process, while in the second grinding process, the grinding process by the finishing grinding unit 100 is performed after the first finishing grinding process. Therefore, the surface grain size of the first wafer W at the start of the second grinding process by the finishing grinding unit 100 is smaller than the surface grain size at the start of the first grinding process. And when the surface state of the first wafer W at the start of the grinding process by the finishing grinding unit 100 changes in this way, even if the re-grinding process of the first wafer W is performed as in the present embodiment, there is a possibility that a desired TTV cannot be obtained.

[0063] In this regard, in the present embodiment, since the re-grinding process is performed by the intermediate grinding unit 90 and the finishing grinding unit 100, the state of the first wafer W during the first grinding process can be preferably reproduced at the start of the re-grinding process by the finishing grinding unit 100, and thereby, the TTV of the first wafer W can be further appropriately improved.

[0064] Furthermore, in the present embodiment, the inclination adjustment between the grinding unit and the chuck 42 during the re-grinding process is performed only by the finish grinding unit 100, and not by the intermediate grinding unit 90. Thereby, the state of the first wafer W at the start of the grinding process by the finish grinding unit 100 can be reproduced more preferably, and the TTV of the first wafer W can be improved more appropriately.

[0065] In the above embodiment, when the grinding unit 40 is configured with three axes, that is, when the grinding unit 40 includes three grinding units (rough grinding unit 80, intermediate grinding unit 90, and finish grinding unit 100), the description has been given by way of example. However, the grinding unit 40 may be configured with two axes, that is, two grinding units (rough grinding unit 80 and finish grinding unit 100). In such a case, the re-grinding process according to the present embodiment is preferably performed in the rough grinding unit 80 and the finish grinding unit 100 based on the thickness distribution of the first wafer W after the first finish grinding.

[0066] As a result of intensive studies by the inventors on the re-grinding process according to the above embodiment, it has been found that the TTV of the first wafer W can be improved more appropriately by making the first grinding amount and the second (re-grinding) amount in the grinding unit 40 uniform. More specifically, for example, when the grinding unit 40 is configured with three axes, the first grinding amount and the second re-grinding amount in the intermediate grinding unit 90, and the first grinding amount and the second re-grinding amount (finish grinding amount) in the finish grinding unit 100 are made uniform, respectively, whereby the TTV of the first wafer W can be appropriately improved.

[0067] As shown in FIG. 8, the inventors performed a grinding process on the first wafer W having a thickness of 775 μm so that the thickness after finish grinding would be 100 μm, and measured the in-plane thickness distribution of the first wafer W after finish grinding. Also, as shown in FIG. 8, in the comparative example and Examples 1 to 3, the grinding amounts in each grinding unit were changed respectively.

[0068] First, as shown in the comparative example of Fig. 8(a), in the grinding unit 40, in the first grinding process, a first grinding process of 635 μm was performed in the pre-finishing grinding unit, and a second grinding process of 20 μm was performed in the finishing grinding unit 100. Further, in the second re-grinding process, only the second re-grinding process of 20 μm was performed in the finishing grinding unit 100. As shown in Fig. 8(a), when the re-grinding process was performed only by the finishing grinding unit 100 in the grinding unit 40, the TTV calculated from the final finishing thickness distribution of the first wafer W was not appropriately improved as compared with the case where the conventional re-grinding process was not performed.

[0069] Next, as shown in Example 1 of Fig. 8(b), in the grinding unit 40, in the first grinding process, a first grinding process of 605 μm was performed in the pre-finishing grinding unit, and a second grinding process of 20 μm was performed in the finishing grinding unit 100. Further, in the second re-grinding process, a first re-grinding process of 30 μm was performed in the pre-finishing grinding unit that performed the first grinding process, and a second re-grinding process of 20 μm was performed in the finishing grinding unit 100. As shown in Fig. 8(b), when the re-grinding process of the first wafer W was performed not only in the finishing grinding unit 100 but also in the pre-finishing grinding unit, the TTV calculated from the final finishing thickness distribution of the first wafer W was improved as compared with the comparative example shown in Fig. 8(a).

[0070] Furthermore, as shown in Example 2 of Fig. 8(c), in the grinding unit 40, in the first grinding process, a first grinding process of 317.5 μm was performed in the pre-finishing grinding unit, and a second grinding process of 20 μm was performed in the finishing grinding unit 100. Further, in the second re-grinding process, a first re-grinding process of 317.5 μm was performed in the pre-finishing grinding unit that performed the first grinding process, and a second re-grinding process of 20 μm was performed in the finishing grinding unit 100. As shown in Fig. 8(c), when the grinding amounts of the first and second times in the pre-finishing grinding unit and the finishing grinding unit 100 were made uniform, the TTV calculated from the final finishing thickness distribution of the first wafer W was improved more than that in Example 1.

[0071] Furthermore, as shown in Example 3 of FIG. 8(d), in the grinding unit 40, in the first grinding process, rough grinding of 575 μm was performed in the rough grinding unit 80, intermediate grinding as the first grinding of 30 μm was performed in the intermediate grinding unit 90, and finish grinding as the second grinding of 20 μm was performed in the finish grinding unit 100. Further, in the second re-grinding process, intermediate grinding as the first re-grinding of 30 μm was performed in the intermediate grinding unit 90, and finish grinding as the second re-grinding of 20 μm was performed in the finish grinding unit 100. As shown in FIG. 8(d), by aligning the grinding amounts of the intermediate grinding unit 90 in the grinding unit 40 and the first and second grindings in the finish grinding unit 100, respectively, the TTV calculated from the final finish thickness distribution of the first wafer W was further improved compared to Example 2.

[0072] As described above, as shown in FIG. 8, by aligning the grinding amount of the first grinding and the grinding amount of the second (re-grinding) in the grinding unit 40, the TTV of the first wafer W can be more appropriately improved.

[0073] Also, as described above, the TTV of the first wafer W after the finish grinding process in Example 3 was further improved compared to the TTV of the first wafer W after the finish grinding process in Example 2. From such a comparison, it is preferable that the grinding amounts in the "first re-grinding" and "second re-grinding" of the first wafer W subjected to the grinding process first on the chuck 42 are the same as the grinding amounts in the "first grinding" as the pre-finish grinding process and the "second grinding" as the finish grinding process of the first wafer W subjected to the grinding process on the nth sheet.

[0074] That is, for example, when the grinding process of the first wafer W is performed by a three-axis grinding unit 40, the re-grinding process is not performed on the n-th first wafer W as described above. Instead, for example, rough grinding of 625 μm, intermediate grinding of 30 μm, and finish grinding of 20 μm are sequentially performed. Here, in the grinding of the n-th first wafer W, such intermediate grinding and finish grinding correspond to "first grinding" and "second grinding", respectively. By making the grinding amounts of the "first re-grinding" and "second re-grinding" for the first first wafer W coincide with the "intermediate grinding amount" and "finish grinding amount" of this n-th wafer, respectively, as shown in the comparison results between Example 2 and Example 3, the TTV of the first wafer W can be further appropriately improved.

[0075] And, in view of the above results, it is desirable that the grinding amount of the first first wafer W by each grinding unit be determined by the following method. That is, first, the grinding amounts of the "first re-grinding" and "second re-grinding" in the second re-grinding process of the first first wafer W are determined so as to match the actual grinding amount of the n-th first wafer W. Next, the grinding amounts of the "first grinding" and "second grinding" in the first grinding process are determined so as to match the grinding amounts in the second re-grinding process. And finally, the difference from the desired grinding amount in the grinding unit 40 is determined as the grinding amount by rough grinding.

[0076] In the above embodiments, the regrinding process is performed only on the first polymer wafer T held by the chuck 42. However, the regrinding process may be similarly performed on the n-th polymer wafer T. Thus, by performing the regrinding process on the n-th polymer wafer T, the TTV of the n-th polymer wafer T can be further improved. However, as described above, in the process of the first polymer wafer T, the inclination of the chuck 42 has already been adjusted, and the change in the parallelism between the finishing grinding unit 100 and the chuck 42 due to the finishing grinding of the polymer wafer T is sufficiently small compared to the change in the parallelism during the standby state of the processing apparatus 1. In view of this point, for the process of the n-th polymer wafer T, instead of performing the regrinding process, by only feeding back the finishing grinding result of the m-th polymer wafer T, the deterioration of the TTV can be appropriately suppressed. Also, compared to the case where the regrinding process is performed on all the polymer wafers T, the grinding process time in the processing apparatus 1 can be shortened.

[0077] In the above embodiments, the relative inclination between the finishing grinding unit 100 and the chuck 42 is adjusted by inclining the chuck base 43 by the inclination adjustment unit 44. However, for example, the relative inclination may be adjusted by inclining the finishing grinding unit 100. Also, for example, if the finishing grinding amount of the first wafer W can be adjusted, the inclination adjustment unit 44 may not be used.

[0078] Also, in the above embodiments, in the polymer wafer T in which the first wafer W and the second wafer S are bonded in the processing apparatus 1, the case where the first wafer W is ground and thinned has been described as an example. However, the first wafer W to be thinned may not be bonded to the second wafer S.

[0079] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

Explanation of Reference Numerals

[0080] 1 Processing apparatus 40 Grinding unit 80 Rough grinding unit 90 Medium grinding unit 100 Finish grinding unit 120 Control unit W First wafer

Claims

1. A method for processing a substrate in a processing apparatus, comprising: holding a substrate on a substrate holding part; performing a finish grinding process on the substrate held by the substrate holding unit in a finish grinding unit; Measuring a finish thickness distribution of the substrate; determining a relative inclination between the substrate holding part and the finish grinding unit based on the measured thickness distribution; Including, Thereafter, the relative inclination between the substrate holding portion and the finish grinding unit is adjusted, and the substrate to be next ground, which is held by the substrate holding portion, is ground by the finish grinding unit.

2. The processing method according to claim 1 , wherein the finish thickness distribution is calculated by a non-contact sensor and a calculation unit, by acquiring a thickness distribution of the substrate from a plurality of measurement results obtained by the non-contact sensor.

3. The processing method according to claim 1 , wherein the substrate held by the substrate holder is subjected to a grinding process in a rough grinding unit before being subjected to a finish grinding process in the finish grinding unit.

4. 4. The processing method according to claim 1, wherein the substrate is a laminated substrate in which a first substrate and a second substrate are bonded together, and the first substrate is subjected to a grinding process.

5. A processing apparatus for performing a grinding process on a substrate, a grinding unit that performs a grinding process on the substrate; A substrate holder for holding the substrate; a thickness distribution measuring unit that measures a thickness distribution of the substrate after the grinding process is performed; A control unit, The control unit is Controlling the operation of the thickness distribution measuring unit so as to measure the thickness distribution of the substrate; The processing apparatus further determines a relative inclination between the substrate holding unit and the grinding unit based on the measured thickness distribution, and then adjusts the relative inclination between the substrate holding unit and the grinding unit to control the grinding process of the substrate so that the substrate to be next ground, which is held by the substrate holding unit, is ground by the grinding unit.

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