TW201816872A - Wafer processing method - Google Patents

Abstract

The present invention relates to a method for processing a wafer, and has a problem of reliably exposing all electrode posts to the back of the wafer. The solution is a method for processing a wafer in which a plurality of electrode posts are embedded and stretched to a thickness direction of a wafer forming a device on the surface, from the wafer surface to a specific depth position. The method includes: holding a wafer on a holding table; The surface-side holding step, and the back-side side of the wafer held by the holding table, thinning the wafer to a specific thickness, and after performing the thinning step, photographing the back of the wafer A photographic image is created, and a judgment step is performed to determine whether there is an electrode pillar that is not exposed on the back surface based on the photographic image. For the case where an electrode pillar that is not exposed on the back surface of the wafer is judged by this judgment step, a thinner wafer is implemented. Those who add engineering steps.

Description

Processing method of wafer

[0001] The present invention relates to a method for processing a wafer composed of a semiconductor or the like.

[0002] A wafer having a device such as an IC, an LSI, or the like is formed on the surface, and a wafer having a substantially circular plate shape in which a plurality of devices are divided is formed. The plurality of devices are formed in a plurality of ranges divided by predetermined division lines set in a grid shape on the surface of the wafer. After a plurality of devices are formed, the wafer is processed from the back side through a grinding device, a polishing device, or the like to be thinned to a specific thickness. The thinned wafer is ground by a cutting device or the like along a predetermined division line, and divided into individual wafers. [0003] Chips with devices are widely used in various electronic devices such as mobile phones and personal computers. The requirements for miniaturization or thinning of various electronic devices have continued to increase. Along with this, the miniaturization or thinning of wafers has also been reviewed, and the area required for chip mounting has been reduced. [0004] In recent years, as a technology for improving the integration degree of a device, a technology in which a plurality of chips are stacked and mounted is put to practical use. In addition, in order to realize the electrical connection between multiple overlapping wafers in a space-saving manner, the technology of electrically connecting the wafers through a through electrode (hereinafter referred to as an electrode post) buried in a hole penetrating the wafer is used. Be practical. Patent Documents 1 and 2 disclose techniques for electrically connecting the stacked wafers with electrode posts. [0005] For example, an electrode pillar is formed by forming a hole of a specific depth from a wafer surface before singulation, and burying a conductive material in the hole. After that, when a thin wafer is processed from the back surface, the bottom of the hole is removed, and the electrode post embedded in the hole is exposed on the back surface side. [Prior Art Document] [Patent Document] [0006] [Patent Document 1] Japanese Patent Laid-Open No. 2001-53218 [Patent Document 2] Japanese Patent Laid-Open No. 2005-136187

[Problems to be Solved by the Invention] [0007] The holes in which the conductive material is embedded are formed to the same depth as the finished thickness of the wafer to be finally formed, but there is unevenness in the depth of each hole. Therefore, even if the back surface of the wafer having a plurality of the holes embedded with a conductive material is processed by a processing device such as a grinding device, a grinding device, or a cutter cutting device, and the wafer is thinned to a design value, all holes cannot be removed. The bottom of the electrode, and a part of the electrode post is not exposed on the back side. [0008] Therefore, when thinning a wafer, it is necessary to confirm whether all the electrode posts are exposed on the back side of the wafer. In the past, the operator visually confirmed the back of the wafer. However, for this purpose, the wafer must be moved from the place where the thinning is performed. When additional processes are required, the wafer must be returned to the original place. Become annoying. In addition, there is a problem that an electrode post or the like which is not exposed is overlooked. [0009] The present invention is constructed in view of the related problems, and an object thereof is to provide a method for processing a wafer that can efficiently determine whether all of the plurality of electrode posts are exposed on the back surface of the thinned wafer. . In addition, if there are unexposed electrode pillars, these are reliably detected and additional processes are performed to provide a processing method for a wafer that can expose all electrode pillars to the back surface. Means for solving the problem [0010] According to one aspect of the present invention, a method for processing a wafer is provided, which is embedded and stretched to a thickness direction of a wafer forming a device on a surface, from the wafer surface to a specific depth position. A method for processing a wafer of a plurality of electrode columns includes a holding step of holding a wafer on a surface side of a holding table, and a method of processing a wafer on a back surface side of the wafer held by the holding table. The thinning of the circle is a thinning step of a specific thickness, and after the thinning step is performed, a photographic image is created by photographing the back surface of the wafer, and based on the photographic image, a determination step is performed to determine whether there is an electrode column that is not exposed on the back surface; In this determination step, it is determined that there is an electrode post that is not exposed on the back of the wafer, and an additional process step for thinning the wafer is performed. [0011] However, in one aspect of the present invention, the determining step is performed while the wafer is held by the holding table, and the additional process step is holding the wafer by the holding table. It is also possible to implement the state. ADVANTAGE OF THE INVENTION [0012] When a wafer processing method related to one aspect of the present invention is adopted, after a thinning step of thinning a wafer to a specific thickness is performed, the back surface of the processed wafer is photographed to create a photographic image, The presence or absence of an electrode post that is not exposed on the back surface can be determined based on the photographed image. This determination is performed, for example, through a photographic image created by comparison and a photographic image in which all the electrode columns are exposed. Therefore, it can be judged in a shorter time than visually, and accurate judgment can be performed. [0013] In order to determine whether all the electrode posts are exposed on the back side of the wafer as soon as possible, and if an additional process is necessary, a judgment for implementing the additional process is given immediately. In addition, after the additional process is performed, it is possible to shorten the time required for the determination when the presence or absence of an electrode column that is not exposed is determined again. [0014] As a result of this judgment, it can be confirmed that all the electrode posts are exposed on the back of the wafer, and no additional process is required. Here, even if it is determined that no additional process is required, the time required for sending the wafer to the next process is shortened because the judgment that no additional process is performed is given immediately. [0015] Furthermore, for this determination, it is possible to determine that the wafer has not been moved from the position where the processing is performed by using a photographic image captured by a photographing unit provided in the processing device. The condition of the wafer is visually observed. Therefore, it is necessary to take out the wafer from the processing device, and when additional processes are performed, the operation of re-arranging the wafer becomes necessary. However, according to the present invention, such operations are not necessary, and the efficiency of processing is improved. [0016] As described above, according to one aspect of the present invention, there is provided a processing method that can efficiently determine whether all wafers having a plurality of electrode posts are exposed on the back surface of the thinned wafer. In addition, in the case where there are unexposed electrode posts, these are reliably detected and additional processing is performed to provide a processing method for a wafer in which all electrode posts are exposed on the back surface.

[0018] An embodiment of the present invention will be described. First, a wafer of an object to be processed in the wafer processing method of the present embodiment will be described. FIG. 1 (A) is a schematic cross-sectional view showing a wafer 1 to be processed. The surface 1a of the wafer 1 is divided into a plurality of ranges by predetermined division lines (not shown) arranged in a grid pattern, and for each of the divided ranges, devices (not shown) such as ICs and LSIs are formed. ). Finally, the wafer 1 is divided along the predetermined division line to form a plurality of wafers. [0019] The wafer 1 is made of, for example, silicon, sapphire, glass, quartz, or the like, and is, for example, a substrate having a slightly circular plate shape. When a wafer made of a semiconductor material is used, the device is formed using, for example, a part of the wafer 1. When the wafer 1 is not made of a semiconductor material, for example, a semiconductor layer is provided on the surface 1 a of the wafer 1 and the semiconductor layer is processed to form a device. [0020] The wafer 1 is provided with a plurality of holes having a specific depth opening on the surface 1a side, a conductive material is introduced into each of the holes, and a plurality of electrode posts 3 elongated in the thickness direction of the wafer 1 are formed. The introduction of the conductive material into the holes is performed by an electrolytic plating method, a CVD method, a vapor deposition method, or the like. In addition, an electric paste containing the conductive material is introduced and cured. After the conductive material is introduced into the hole by these methods, the surface 1a side of the wafer 1 is planarized by a CMP method or the like in order to remove the excess conductive material that is supplied excessively and not contained in the hole. [0021] As the conductive material, for example, a material such as gold, silver, copper, or aluminum is used. The electrode post 3 is used because it is electrically connected between the stacked wafers. For the conductive material, a material having a low electrical impedance may be used. [0022] When the wafer 1 is processed from the back surface 1b side to be thinned to a specific thickness, the bottom of the hole into which the conductive material is introduced is removed, so that the electrode post 3 is exposed on the back surface 1b side. The completed thickness after the wafer 1 is thinned is formed deep. [0023] In the processing method related to this embodiment, before the back surface 1b of the wafer 1 is processed, as shown in FIG. 1 (B), the supporting wafer 5 of the device for protecting the surface 1a is attached to the supporting wafer 5. Surface 1a. As the support wafer 5, for example, a silicon wafer is used. Instead of supporting the wafer 5, a protective tape may be attached to the surface 1 a of the wafer 1. [0024] Next, a processing apparatus suitable for implementing a processing method for a wafer according to this embodiment will be described. FIG. 2 is a perspective view showing an example of the processing apparatus. The processing device 2 is a device that can perform processing such as grinding processing and polishing processing on wafers. [0025] The processing device 2 includes a stage 4 having a slightly rectangular parallelepiped shape. In the vicinity of the upper end of the table 4, a columnar shape 6 having a slightly rectangular parallelepiped shape is erected. The front surface of the processing device 2 of the column 6 is provided with two pairs of rails 8 and rails 10 extending in the up-down direction. [0026] The 8-track rough grinding unit 12 on one side is movably mounted in the up-down direction (Z-axis direction) via the rough-grinding unit transfer mechanism 14, and the 10-track precision grinding on the other side The unit 16 is movably mounted in the up-down direction via a precision grinding unit transfer mechanism 18. [0027] A detailed configuration of the rough grinding unit 12 will be described with reference to FIGS. 2 and 3 (B). The rough grinding unit 12 includes a cylindrical storage unit 20 and a motor 32 that is rotationally driven and rotatably stored in a spindle 22 of the storage unit 20. The front end of the mandrel 22 is exposed from the lower surface of the storage unit 20 to the outside. [0028] The rough grinding unit 12 further includes a disc-shaped wheel set seat 24 fixed to the front end of the spindle 22, and a grinding wheel set 26 that is freely mounted on the front end of the wheel set seat 24. The grinding wheel set 26 is composed of a disc-shaped wheel set base 28 having a diameter approximately equal to that of the wheel set seat 24, and a plurality of grinding wheels 30 fixedly mounted in a ring shape on the periphery of the lower end surface of the wheel set base 28. Make up. [0029] The fine grinding unit 16 is configured in the same manner as the rough grinding unit 12. However, the grinding wheel set of the fine grinding unit 16 is compared with the grinding wheel of the rough grinding unit 12, and a grinding wheel suitable for smooth grinding of the wafer is used. [0030] As shown in FIG. 2, the processing device 2 includes a turntable 34 which is slightly parallel to the upper surface of the table 4 before the pillar 6. The turntable 34 is rotated in a direction indicated by an arrow 36 via a rotation driving mechanism (not shown). The four holding tables 38 on the turntable 34 which are 90 degrees apart from each other in the circumferential direction are arranged rotatably in a horizontal plane. [0031] A porous member 38a is disposed on the upper portion of the holding table 38, and the upper surface of the porous member 38a becomes a holding surface (see FIG. 4). The holding table 38 has a suction path 38b inside which one end is connected to a suction source (not shown). The other end of the suction path 38b is connected to the porous member 38a (see FIG. 4). The holding table 38 is a wafer 1 that is placed on the holding surface through the porous member 38a, and a negative pressure generated by the suction source acts to suck and hold the wafer 1. [0032] The four holding tables 38 of the turntable 34 arranged on the turntable 34 are sequentially moved to the wafer loading / unloading range A, the rough grinding processing range B, the fine grinding processing range C, and the grinding processing through suitable ones. Range D. Each of the holding tables 38 is provided around a vertical axis on which the holding surface can be rotated, and is rotated when the wafer 1 is ground or the like to rotate the wafer 1. [0033] A first polishing unit 40 is provided for the polishing processing range D. The first grinding unit 40 includes a stationary block (not shown) fixed on the table 4 and an X-axis movement that can be moved in the X-axis direction through an X-axis moving mechanism (not shown) mounted on the stationary block. A block (not shown) and a Z-axis moving block (not shown) that can be moved in the Z-axis direction through a Z-axis moving mechanism (not shown) mounted on the X-axis moving block. [0034] A cylindrical storage unit (not shown) is provided for the Z-axis moving block, and the storage unit 42 is rotatably received in the storage unit as shown in FIG. 4. The front end of the mandrel 42 is exposed to the outside from below the storage unit. A disc-shaped wheel set seat 44 is fixed to the front end of the mandrel 42, and a grinding wheel set 46 is detachably attached to the wheel set seat 44. [0035] The polishing wheel set 46 is composed of a disc-shaped base 48 having a diameter approximately equal to that of the wheel base 44 and a polishing pad 50 attached to the base 48. The abutment 48 side of the grinding wheel set 46 is mounted on the wheel set seat 44. The polishing pad 50 is, for example, a felt material in which abrasive particles are dispersed in a polyurethane or a felt and fixed with an adhesive. A polishing liquid supply path 52 is formed in the center of the base 48 and the polishing pad 50. Furthermore, a plurality of grooves (not shown) are formed on the polishing surface (lower surface) of the polishing pad 50 to hold a plurality of polishing liquids. [0036] A second polishing unit 40a is provided between the wafer loading / unloading range A and the polishing processing range D. The second polishing unit 40 a is configured in the same manner as the first polishing unit 40. [0037] For the opposite side of the column 6 of the stage 4 of the processing apparatus 2, for example, a first cassette 62 for detachably storing and storing wafers before processing, and, for example, a wafer for storing processed wafers The second cassette 64. [0038] The wafer transfer robot arm 66 transfers the wafers stored in the first cassette 62 to the temporary placement table 68. In addition, the processed wafers that have been cleaned by the rotary cleaning unit 70 are transferred to the second cassette 64. [0039] The transfer unit 72 transfers wafers from a temporary placement table 68 to a holding table 38 placed in a wafer transfer / unloading range A. In addition, the processed wafer is sucked and transferred from the holding table 38 to the rotary cleaning unit 70. The transfer unit 72 can move the wafer to the X-axis direction, the Y-axis direction, and the Z-axis direction. [0040] At least one of the rough grinding unit 12, the fine grinding unit 16, the first grinding unit 40, and the second grinding unit 40a of the processing device 2 is further provided with a photograph used for confirming the state or processing position of the workpiece. unit. In addition, this imaging unit can also be used in the determination step regarding the processing method of this embodiment. This imaging unit is formed by, for example, a line sensor including a plurality of imaging elements arranged linearly in a rod-shaped housing. [0041] As shown in FIG. 5 (A), the long axis of the rod-shaped frame of the photographing unit 54 is parallel to the wafer 1, and is disposed above the end of the wafer 1. The photographing unit 54 is moved in a horizontal plane in a direction perpendicular to the long axis of the frame (the direction of the arrow in FIG. 5 (A)). At the same time, the processed wafer 1 is photographed to create a photographic image, and the photographic image is transmitted to A controller (control unit) 56 of the processing device 2. [0042] As shown in FIG. 2, the processing device 2 includes a controller (control unit) 56 connected to the stage 4. The controller (control unit) 56 has a function of controlling each component of the processing device 2. In addition, in a determination step described later, the controller (control unit) 56 receives a photographed image from the photographing unit 54 and determines whether all the electrode columns 3 are exposed on the back surface 1 b side of the wafer 1 based on the photographed image. However, the configuration and function of the controller (control unit) 56 may be implemented as software on a PC. [0043] The controller (control unit) 56 includes a determination unit 58 and a standard image storage unit 60. The standard image storage unit 60 holds a photographic image of the back surface 1b side of the wafer 1 that is correctly processed as a standard image. In the determination step described later, the determination unit 58 compares the standard image read from the standard image storage unit 60 with the photographed image transmitted from the photographing unit 54 and determines whether or not the electrode post 3 is not exposed on the back surface. [0044] When it is determined by the determination unit 58 that the electrode post 3 is not exposed, the controller (control unit) 56 transfers the wafer 1 to the next step. When it is determined by the determination unit 58 that the electrode post 3 is not exposed, the wafer is processed again in a processing unit (grinding processing or polishing processing) in which the photographing unit 54 is mounted. However, after the wafer is processed again, a determination is made to create a photographic image for the imaging unit 54 again. [0045] Next, a method for processing a wafer according to this embodiment will be described. First, as shown in FIG. 3 (A), the wafer 1 having a plurality of devices formed on the surface 1a is subjected to a holding step for holding the wafer 38 in the wafer loading / unloading range A located in the processing device 2. The surface 1a of the wafer 1 is provided with a surface protection member supporting the wafer 5 in advance, and the wafer 1 is placed on the holding table 38 with the surface 1a side facing the holding surface of the holding table 38. Attract keep. [0046] Next, a thinning step of thinning the wafer 1 is performed by processing the back surface 1b side of the wafer 1 held on the holding table 38. In this thinning step, at the same time as the wafer 1 is thinned, the bottom of the hole in which the electrode pillar 3 of the wafer 1 is buried is removed, and the electrode pillar 3 is exposed on the back surface 1 b side of the wafer 1. [0047] The thinning step of exposing the electrode column 3 is performed using, for example, the rough grinding unit 12, the fine grinding unit 16, the first grinding unit 40, and the second grinding unit 40a of the processing device 2. Processing of the wafer 1 in each of these units will be described below. [0048] First, the turntable 34 is rotated, the holding table 38 is transferred to the rough grinding processing range B, and then the wafer 1 is moved. Then, the back surface 1 b of the wafer 1 is roughly ground by the rough grinding unit 12. FIG. 3 (B) is a side view illustrating rough grinding. [0049] In rough grinding, first, the holding table 38 and the grinding wheel set 26 are each rotated in the direction of the arrow shown in FIG. 3 (B). Then, in a state where both are rotated, the rough grinding unit conveying mechanism is operated, and the grinding wheel set 26 is machined and conveyed downward. In addition, when the grinding stone 30 held by the grinding wheel group 26 is in contact with the wafer 1, the back surface 1 b side of the wafer 1 is roughly ground. When the rough grinding of the wafer 1 reaches a specific thickness, the rough grinding is finished. [0050] Next, the turntable 34 of the processing device 2 is rotated, and the holding table 38 is transferred to the fine grinding processing range C. Then, the wafer 1 is finely ground through the fine grinding unit 16. However, the fine grinding by the fine grinding unit 16 is performed in the same manner as the rough grinding by the rough grinding unit 12. [0051] Fine grinding is carried out at a slower feed speed than rough grinding, and the ground surface after grinding is smoothly implemented. The back surface 1b of the wafer 1 is thinned to a thickness of the finished thickness of the wafer through rough grinding and fine grinding. [0052] After finishing grinding, the turntable 34 is rotated, and the holding table 38 is transferred to the polishing processing range D. Then, the back surface 1 b side of the wafer 1 is polished by the first polishing unit 40. FIG. 4 is a cross-sectional view schematically showing polishing on the back surface 1b side of the wafer 1 passing through the first polishing unit 40. [0053] While the wafer 1 held on the holding table 38 is supplied with the polishing liquid through the polishing liquid supply path 52, the holding table 38 and the polishing pad 50 are each rotated by the arrows shown in FIG. 4. direction. Then, the Z-axis moving mechanism is operated to bring the polishing pad 50 into contact with the back surface 1 b of the wafer 1, and the polishing pad 50 is directly pressed toward the back surface 1 b of the wafer 1 to perform polishing. [0054] Next, the turntable 34 is rotated to transfer the holding table 38 to the wafer loading / unloading area A. The wafer 1 is further polished by the second polishing unit 40a. However, the polishing by the second polishing unit 40 a is performed in the same manner as the polishing by the first polishing unit 40. When the back surface 1b of the wafer 1 is further thinned by polishing performed by the first polishing unit 40 and the second polishing unit 40a, the polishing warpage of the back surface 1b of the wafer 1 is removed. [0055] Here, any of the grinding performed by the rough grinding unit 12, the grinding performed by the fine grinding unit 16, the grinding performed by the first grinding unit 40, or the grinding performed by the second grinding unit 40a. In one process, the bottom of the hole in which the electrode post 3 is buried is removed. The electrode post 3 is exposed on the back surface 1b side of the wafer 1. However, the hole system formed in the wafer 1 has unevenness in depth and is processed under specific conditions. In some cases, all of the plurality of electrode posts 3 are not exposed on the back surface 1 b side of the wafer 1. [0056] If the electrode pillars 3 are not exposed on the back surface 1b side of the wafer 1, when a plurality of wafers formed by dividing the wafer 1 are laminated to form a laminated body, the electrode pillars 3 cannot be properly formed. Because of the connection between the wafers, the layered system does not function properly. Therefore, all of the electrode posts 3 formed on the wafer 1 must be exposed on the back surface 1 b of the wafer 1. [0057] Therefore, in the wafer processing method related to this embodiment, a thinning step of exposing the electrode post 3 to the back surface 1b side is performed, and then a determination step is performed. In this determination step, the back surface 1b of the wafer 1 is photographed to create a photographic image, and the presence or absence of the electrode post 3 not exposed on the back surface 1b is determined based on the photographed image. [0058] As described above, the rough grinding unit 12, the fine grinding unit 16, the first grinding unit 40, or the second grinding unit 40a is provided with the photographing unit 54. Via this imaging unit 54, the back surface 1 b side of the processed wafer 1 is photographed to create a photographic image. FIG. 5 (A) is a side view showing the imaging on the back surface 1b side of the wafer 1 using the imaging unit 54. FIG. The photographing step is performed directly after the wafer 1 is held on the holding table 38 after the thinning step. [0059] In the judging step, first, the rod-shaped frame of the photographing unit 54 is oriented in parallel with the wafer 1 and placed above the end of the wafer 1. In addition, the photographing unit 54 is moved in a horizontal plane in a direction perpendicular to the long axis of the frame (the direction of the arrow in FIG. 5 (A)), and the processed wafer 1 is photographed to create a photographic image, and the photographic image is taken. It is transmitted to the controller (control part) of the processing apparatus 2. [0060] FIGS. 5 (B) and 5 (C) each show an example of a photographic image captured by the photographing unit 54. FIG. 5 (B) is a photographic image 7 showing that a part of the plurality of electrode posts 3 formed on the wafer 1 is not exposed on the back surface 1b side of the wafer 1, and FIG. 5 (C) shows all the electrode posts 3 Photographic image 9 of the wafer 1 exposed on the back surface 1b side. [0061] The photographic image 9 shown in FIG. 5 (C) is a standard image that shows a state where the thinning step is normally performed, and is stored in advance in the standard image of the controller (control unit) 56 of the processing device 2. Department 60. [0062] The determination unit 58 of the controller (control unit) 56 that receives the photographed image from the self-photographing unit 54 is connected to the standard image storage unit 60. When the self-photographing unit 54 receives the photographic image, it saves it from the standard image. The unit 60 reads a standard portrait as shown in FIG. 5 (C). Then, the photographic image is compared with the standard image, and it is determined whether all the electrode columns 3 can be exposed on the back surface of the wafer 1. [0063] This determination is performed, for example, by comparing two images. When the two images are determined to be the same through this comparison, the determination unit determines that there is no electrode post 3 that is not exposed on the back surface 1 b side of the wafer 1. On the other hand, when it is determined that the two images are not consistent, the determination unit determines that there is an electrode post 3 that is not exposed on the back surface 1 b side of the wafer 1. However, in the comparison of the two images, the two may be completely the same. For example, in the error range of the formation position of each electrode column 3, a position deviation is allowed. [0064] The determination unit 58 determines that there is no electrode post 3 that is not exposed on the back surface 1b side of the wafer 1, and the processing device 2 performs the thinning step subsequent to the wafer 1. In this way, even if the thinning step is normally performed without additional engineering, in the wafer processing method related to this embodiment, the judgment of the necessity of no processing engineering is immediately issued, and the processing related to this embodiment is passed. The method can speed up the project. [0065] The determination unit 58 determines that the electrode post 3 is not exposed on the back surface 1b side of the wafer 1, and performs additional processing on the wafer 1 maintained and held on the holding table 38. The additional processing is performed so that all the electrode posts 3 are exposed on the back surface 1 b side of the wafer 1. The additional processing is directly performed using a processing unit used in the thinning step. [0066] In the method for processing a wafer according to this embodiment, it is not necessary to move the holding table 38 or the wafer 1 when determining or performing additional processing, and it is possible to quickly perform additional processing on the wafer 1. The additional process is the same process as the process performed in the thinning step, for example, to reduce the processing time and the like. After the additional process is performed, the above-mentioned determination step is performed again, and after the determination that all the electrode columns 3 are exposed is obtained, the next step is performed. [0067] In the method for processing a wafer according to this embodiment, the back surface 1b of the wafer 1 is photographed via the imaging unit 54 to create a photographic image, and the presence or absence of the electrode post 3 not exposed on the back surface 1b is determined based on the photographic image . Therefore, compared with the case where the wafer 1 is peeled from the holding table 38 and the operator makes a visual judgment, the judgment can be performed quickly and reliably. Furthermore, since the determination can be performed without moving the holding table 38, the additional process can be performed on the wafer 1 at the original position even if the implementation of the additional process is necessary. [0068] However, the present invention is not limited to the description of the embodiment described above, but can be implemented with various changes. For example, in a case where an additional process is performed in accordance with the determination of the determination unit 58, in order to determine the degree of the additional process to be performed, the ratio of the electrode posts 3 exposed on the back surface 1 b side among the plurality of electrode posts 3 may be derived. Considering the general distribution of the depth of the holes in which the electrode posts 3 are embedded, the lower the ratio, the greater the distance from the back surface 1b at the bottom of the shallowest hole. Therefore, the content of the additional work may be determined by considering the correlation between the ratio and the intensity of the necessary additional work. [0069] For example, the number of electrode posts 3 reflected on a standard image and the number of electrode posts 3 reflected on a photographic image created by a photographing unit are detected. Then, the ratio of the exposed electrode post 3 is derived for the whole. If the ratio of the exposed electrode columns 3 is relatively low, an additional process may be performed with high strength in order to expose all the electrode columns 3. On the other hand, the ratio of the exposed electrode pillars 3 is relatively high, and it is only necessary to perform additional engineering with low strength. [0070] In this way, when the content of the additional process can be determined using a photographic image, the minimum necessary additional process can be performed on the exposed electrode post 3, and the time required for the additional process can be suppressed and suppressed. The cost of money. [0071] In one aspect of the present invention, the judging step may be performed at a place different from the thinning step, and reprocessing may be performed. For example, when fine grinding is performed as a thinning step, the determination step may be performed after grinding, and re-processing may be performed from rough grinding. [0072] In addition, the structures, methods, etc. of the above-mentioned embodiments can be appropriately modified and implemented as long as they do not depart from the scope of the present invention.

[0073]

1‧‧‧ wafer

1a‧‧‧ surface

1b‧‧‧ back

3‧‧‧ electrode post

5‧‧‧Support Wafer

7, 9‧‧‧ Photography portraits

2‧‧‧Processing equipment

4‧‧‧ units

6‧‧‧ cylinder

8,10‧‧‧track

12‧‧‧ Rough grinding unit

14‧‧‧ Rough grinding unit transfer mechanism

16‧‧‧Fine grinding unit

18‧‧‧ Conveying mechanism of precision grinding unit

20‧‧‧Storage unit

22‧‧‧ mandrel

24‧‧‧ Wheel Block Seat

26‧‧‧Grinding wheel set

28‧‧‧ Wheel Abutment

30‧‧‧grinding stone

32‧‧‧ Motor

34‧‧‧ Turntable

36‧‧‧ Arrow

38‧‧‧holding table

38a‧‧‧Porous member

38b‧‧‧attraction path

40, 40a‧‧‧grinding unit

42‧‧‧ mandrel

44‧‧‧ Wheel Block Seat

46‧‧‧Grinding wheel set

48‧‧‧ abutment

50‧‧‧Grinding pad

52‧‧‧Grinding fluid supply path

54‧‧‧Photography Unit

56‧‧‧Controller (Control Department)

58‧‧‧Judging Department

60‧‧‧Standard portrait preservation department

62, 64‧‧‧ Cassette

66‧‧‧ Wafer Transfer Robot

68‧‧‧Temporary placement table

70‧‧‧Rotary washing unit

72‧‧‧ transport unit

[0017] FIG. 1 (A) is a schematic cross-sectional view showing a wafer in which a plurality of electrode columns are embedded, and FIG. 1 (B) is a cross-sectional schematic view showing a case where a supporting wafer is provided on a wafer surface. FIG. 2 is a perspective view schematically showing an example of a processing device. FIG. 3 (A) is a side view illustrating a holding step, and FIG. 3 (B) is a side view illustrating an example of a thinning step. FIG. 4 is a cross-sectional view illustrating another example of the thinning step. FIG. 5 (A) is a side view explaining the determination procedure, FIG. 5 (B) is a schematic diagram showing one example of a photographic portrait, and FIG. 5 (C) is a schematic diagram showing another example of a photographic portrait.

Claims (2)

A wafer processing method is a method for processing a wafer in which a plurality of electrode posts extending from the surface of the wafer to a specific depth are stretched in the thickness direction of the wafer in which a device is formed on the surface, and is characterized by: A holding step of holding the wafer to hold the surface side of the wafer, and a thinning step of thinning the wafer to a specific thickness by processing the back side of the wafer held by the holding table, and then performing the thinning step. A photographic image is prepared by photographing the back surface of the wafer, and a determination step is performed based on the photographic image to determine whether there is an electrode pillar that is not exposed on the back surface; Additional engineering steps for thinner wafers. For example, the method for processing a wafer described in the first patent application range, wherein the determination step is performed while the wafer is held by the holding table, and the additional engineering step is held by the holding table. The state of the wafer is executed.