Wafer processing method and wafer processing system

Abstract

To provide a method and a system for machining a wafer, which can remove machining chips stuck to the surface of the wafer.SOLUTION: The method for machining the wafer comprises: an outer edge removal step of removing the outer edge of a first wafer 100 having a first wiring layer 120 formed on the surface 101 from the surface 101 side; and a polishing step of polishing the first wiring layer 120 of the surface 101 side of the first wafer 100 after the execution of the outer edge removal step.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present invention relates to a method for processing a wafer and a wafer processing system. 【Background Art】 【0002】 A method of bonding the surface of a first wafer and the surface of a second wafer to form a bonded wafer is known (see, for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2021-068744 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 In a process of holding the back surface side of a wafer having a wiring layer formed on its surface on a holding table and performing trimming to remove the outer edge portion of the wafer from the front surface side, there was a risk that processing debris would remain on the surface of the wafer. In particular, when the wiring layer on the surface of the wafer was exposed and the wiring layer of the wafer was bonded to another wafer after trimming, there was a risk that bonding failure would occur if the processing debris during trimming adhered to the wiring layer. 【0005】 The present invention has been made in view of such problems, and an object thereof is to provide a method for processing a wafer and a wafer processing system capable of removing processing debris adhering to the surface of the wafer. 【Means for Solving the Problems】 【0006】 To solve the above-mentioned problems and achieve the objective, the wafer processing method of the present invention comprises: an outer edge removal step of removing the outer edge portion of a first wafer on which a first wiring layer is formed on its surface from the surface; and a polishing step of polishing the surface of the first wafer after the outer edge removal step has been performed. The polishing step begins with the processing fluid supplied in the edge removal step remaining on the surface of the first wafer. It is characterized by the following: 【0007】 The method further includes a bonding step of bonding the first wafer and a second wafer having a second wiring layer formed on its surface, wherein the first wiring layer and the second wiring layer may be joined in the bonding step. 【0008】 In the edge removal step, the thickness removed from the surface is greater than the finished thickness of the first wafer, and the process may further include a backside grinding step in which the back surface of the first wafer is ground to the finished thickness after the bonding step is performed. 【0009】 The polishing step may be wet polishing using a polishing solution. 【0011】 Furthermore, in order to solve the above-mentioned problems and achieve the objective, the wafer processing system of the present invention comprises: a holding table for holding the back side of a first wafer on which a wiring layer is formed on its surface; an outer edge removal unit for removing the outer edge from the front side of the first wafer held on the holding table; a polishing unit for polishing the surface of the first wafer from which the outer edge has been removed by the outer edge removal unit; a cleaning unit for cleaning the first wafer polished by the polishing unit; and a transport unit for transporting the first wafer between the outer edge removal unit, the polishing unit, and the cleaning unit. The polishing unit starts polishing while the processing fluid supplied by the outer edge removal unit remains on the surface of the first wafer. It is characterized by the following: 【0012】 The polishing unit may include a polishing pad that contacts the first wafer and a polishing fluid supply unit that supplies polishing fluid to the processing point. [Effects of the Invention] 【0014】 The wafer processing method of the present invention includes a polishing step after the outer edge removal step, which allows for the effective removal of processing debris adhering to the first wiring layer before it dries and hardens on the first wiring layer during the outer edge removal step. Furthermore, the polishing step removes processing debris adhering to the first wiring layer, as well as abnormal oxidation and corrosion layers, exposing a surface that is not abnormally oxidized or corroded for bonding. This reduces the risk of bonding defects caused by abnormal oxidation or corrosion layers in the first wiring layer. Additionally, since the outer edge of the first wafer is removed in the outer edge removal step to form a trimming groove deeper than the finished thickness before the back grinding step, the risk of the first wafer forming a sharp edge and chipping during the back grinding step can be prevented. Furthermore, since the polishing process performed by the polishing unit in the polishing step is a wet polishing process using polishing fluid supplied to the processing point by the polishing fluid supply unit, the polishing fluid removes the abnormal oxidation layer or corrosion layer formed on the exposed surface of the first wiring layer, exposing a surface that is not abnormally oxidized or corroded. This reduces the risk of bonding defects between the first wiring layer and the second wiring layer of the second wafer caused by the abnormal oxidation layer or corrosion layer of the first wiring layer. 【0015】 Furthermore, the wafer processing system of the present invention includes an outer edge removal unit for removing the outer edge of the first wafer, a polishing unit for polishing the first wiring layer, and a transport unit for transporting the first wafer between the outer edge removal unit and the polishing unit. As a result, the wafer processing method of the present invention described above can be implemented, and the polishing unit can polish the first wiring layer while the processing fluid supplied when the outer edge is removed by the outer edge removal unit remains on the first wiring layer of the first wafer. Therefore, processing debris adhering to the first wiring layer when the outer edge is removed can be suitably removed before it dries and hardens on the first wiring layer. This reduces the risk of bonding defects between the first wiring layer and the second wiring layer of the second wafer caused by processing debris. [Brief explanation of the drawing] 【0016】 [Figure 1]Figure 1 is a flowchart showing the processing procedure for the wafer processing method according to the embodiment. [Figure 2] Figure 2 is a top view showing an example of the configuration of a wafer processing system according to an embodiment. [Figure 3] Figure 3 is a cross-sectional view illustrating the holding table and outer edge removal unit shown in Figure 2. [Figure 4] Figure 4 is a cross-sectional view illustrating the polishing unit shown in Figure 2. [Figure 5] Figure 5 is a cross-sectional view illustrating the cleaning unit shown in Figure 2. [Figure 6] Figure 6 is a cross-sectional view illustrating the bonding step in Figure 1. [Figure 7] Figure 7 is a cross-sectional view illustrating the backside grinding step in Figure 1. [Modes for carrying out the invention] 【0017】 Embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention. 【0018】 [Embodiment] A wafer processing method and a wafer processing system 1 according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a flowchart showing the processing steps of the wafer processing method according to the embodiment. As shown in Figure 1, the wafer processing method according to the embodiment comprises an outer edge removal step 1001, a polishing step 1002, a cleaning step 1003, a bonding step 1004, and a back surface grinding step 1005. 【0019】 FIG. 2 is a top view showing a configuration example of a wafer processing system 1 according to an embodiment. The outer edge removal step 1001, polishing step 1002, and cleaning step 1003 of the wafer processing method according to the embodiment are performed, for example, by the wafer processing system 1 shown in FIG. 2. As shown in FIG. 2, the wafer processing system 1 includes a holding table 10, an outer edge removal unit 20, a back surface cleaning unit 30, a polishing unit 40, a cleaning unit 50, a transfer unit 60, a cassette mounting table 70, a temporary placement table 75, and a control unit 80. 【0020】 A first wafer 100 which is a processing target of the wafer processing method and the wafer processing system 1 according to the embodiment has a first wiring layer 120 laminated on a first substrate 110. The first substrate 110 is, for example, a disk-shaped semiconductor wafer, an optical device wafer, or a disk-shaped substrate such as glass, ceramics, resin, or metal, with a base material such as silicon, sapphire, silicon carbide (SiC), gallium arsenide, or glass. The first wafer 100 has, for example, a device formed of the chip-sized first wiring layer 120 in a region partitioned by a plurality of division planned lines formed in a grid pattern on the surface 111 of the first substrate 110. The first wiring layer 120 is formed of, for example, a metal such as copper (Cu). Thus, the surface 101 of the first wafer 100 is the exposed surface of the first wiring layer 120. The back surface 102 of the first wafer 100 is the back surface 112 (exposed surface) of the first substrate 110 in this embodiment, but the present invention is not limited thereto, and it may be supported by a support substrate or an adhesive tape not shown. 【0021】 FIG. 3 is a cross-sectional view for explaining the holding table 10 and the outer edge removal unit 20 of FIG. 2. The holding table 10 is a so-called chuck table in the present embodiment, and includes a disk-shaped frame body in which a concave portion is formed, and a disk-shaped suction portion fitted into the concave portion. The suction portion of the holding table 10 has a porous portion formed of a porous ceramic or the like provided with a large number of porous holes, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). The upper surface of the suction portion of the holding table 10 is a holding surface 11 on which the first wafer 100 is placed and the placed first wafer 100 is sucked and held by the negative pressure introduced from the vacuum suction source. As shown in FIG. 3, in the present embodiment, the first wafer 100 is placed with the surface 101 side facing upward, and the back surface 102 side of the placed first wafer 100 is sucked and held on the holding surface 11. The holding surface 11 and the upper surface of the frame body of the holding table 10 are arranged on the same plane and are formed parallel to the XY plane which is a horizontal plane. 【0022】 The holding table 10 is provided so as to be movable in the X-axis direction parallel to the horizontal direction between the loading / unloading area 17 and the processing area 18 by the third transfer unit 63 (see FIG. 2) of the transfer unit 60, and is provided so as to be rotatable around the Z axis orthogonal to the horizontal plane (XY plane) and parallel to the vertical direction by a rotation drive source (not shown). Here, the loading / unloading area 17 is an area where the first wafer 100 is loaded and unloaded by the second transfer unit 62 and the fourth transfer unit 64 of the transfer unit 60. The processing area 18 is an area where the first wafer 100 is subjected to a cutting process by the outer edge removal unit 20. 【0023】 As shown in FIGS. 2 and 3, the outer edge removal unit 20 is provided in the processing area 18, and includes a spindle 22 to which a cutting blade 21 is attached at the tip, and a processing liquid supply unit 23, and performs a cutting process on the first wafer 100 held on the holding table 10 positioned in the processing area 18. The outer edge removal unit 20 is provided so as to be movable in the Y-axis direction parallel to the horizontal direction and orthogonal to the X-axis direction by a Y-axis direction movement unit 25, and is provided so as to be movable in the Z-axis direction by a Z-axis direction movement unit 26. 【0024】 As shown in Figure 3, the outer edge removal unit 20 supplies processing fluid 29 onto the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100 by the processing fluid supply unit 23. The rotational movement of the spindle 22 applies rotational motion of the cutting blade 21 around an axis parallel to the Y-axis direction. The cutting blade 21 is positioned to cut into the outer edge of the first wafer 100, held by the holding table 10, to a predetermined depth deeper than the finished thickness 150 (see Figures 3 and 7) of the first wafer 100, from the surface 101. The rotational drive source is then controlled to rotate the holding table 10 holding the first wafer 100 around the Z-axis, thereby performing an outer edge removal process (so-called edge trimming process) to cut and remove the entire circumference of the outer edge of the first wafer 100 in an annular shape, deeper than the finished thickness 150 of the first wafer 100, to form a trimming groove 140. Here, the processing fluid 29 is, for example, pure water. Furthermore, the finished thickness 150 of the first wafer 100 refers to the thickness of the first wafer 100 after the back grinding step 1005 is performed, and in this embodiment, for example, it is thinner than the combined thickness of the first substrate 110 and the first wiring layer 120 before the back grinding step 1005 is performed. The wafer processing system 1, as shown in Figure 2, is equipped with two sets of outer edge removal units 20, that is, a two-spindle die, a so-called facing dual type processing system. 【0025】 As shown in Figure 2, the back surface cleaning unit 30 includes a wafer support section 31 and a cleaning section 32. In this embodiment, there are multiple wafer support sections 31 (four at 90-degree intervals in the example shown in Figure 2). The multiple wafer support sections 31 support the outer peripheral surface of the edge of the first wafer 100 by clamping it from the outer peripheral side. The multiple wafer support sections 31 rotate in conjunction with each other, thereby allowing the first wafer 100 to rotate. The cleaning section 32 is installed below the wafer support sections 31 and facing upward, and contacts the back surface 102 of the first wafer 100 supported by the wafer support sections 31 to clean the back surface 102. The cleaning section 32 is made of a material that is softer and more deformable than the first substrate 110, and can deform to conform to the first substrate 110 and make surface contact with it, such as a sponge or a brush. 【0026】 Figure 4 is a cross-sectional view illustrating the polishing unit 40 shown in Figure 2. As shown in Figures 2 and 4, the polishing unit 40 comprises a holding table 41, a spindle 42, a polishing pad 44 attached to a mount 43, and a polishing fluid supply unit 45. The holding table 41 has a structure similar to that of the holding table 10, with a suction portion and a porous portion, and holds the back surface 102 of the first wafer 100, which is placed with its surface 101 facing upward, by suction with the holding surface 46. The holding table 41 is rotatable around the Z axis by a rotation drive source (not shown). 【0027】 The spindle 42 is cylindrical in shape, with a disc-shaped mount 43 fixed to its lower end, and a circular polishing pad 44 mounted on the lower surface of the mount 43. The spindle 42 rotates around an axis parallel to the vertical Z-axis direction. The polishing unit 40 performs a polishing process in which the first wiring layer 120 is polished by the polishing pad 44. This is achieved when the mount 43 and polishing pad 44 are subjected to rotational motion around the axis parallel to the Z-axis direction by the rotational motion of the spindle 42, causing the polishing pad 44 to contact and press against the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100 held on the holding table 41. The polishing fluid supply unit 45 supplies polishing fluid 49 to the processing point through a polishing fluid channel 47 that extends in the Z-axis direction from the inside of the mount 43 to the inside of the spindle 42. Here, the processing point refers to any position within the region where the exposed surface of the first wiring layer 120 of the first wafer 100 is being polished by the polishing pad 44. 【0028】 The spindle 42 is provided to be movable between a polishing position in which a mount 43 fixed to its lower end and a polishing pad 44 attached to the mount 43 perform polishing on the first wafer 100 held on the holding table 41, and an loading / unloading position in which it is retracted from the holding table 41 to enable loading the first wafer 100 onto the holding table 41 and unloading the first wafer 100 from the holding table 41. 【0029】 In this embodiment, the polishing pad 44 is made of, for example, a nonwoven fabric or an elastic resin such as urethane. The polishing pad 44 may or may not contain fixed abrasive grains. In this embodiment, the polishing unit 40 may perform wet polishing on the first wiring layer 120 using the polishing pad 44 while supplying polishing fluid 49 from the polishing fluid supply unit 45, or it may perform dry polishing on the first wiring layer 120 using the polishing pad 44 without supplying polishing fluid 49 from the polishing fluid supply unit 45. The polishing unit 40 may perform wet polishing by supplying a slurry containing abrasive particles as polishing fluid 49 from the polishing fluid supply unit 45 and polishing the first wiring layer 120 with the polishing pad 44; or it may perform polishing using a polishing pad 44 containing fixed abrasive particles while supplying pure water as polishing fluid 49 from the polishing fluid supply unit 45; or it may perform chemical mechanical polishing (CMP) using the polishing pad 44 while supplying an alkaline polishing fluid as polishing fluid 49 from the polishing fluid supply unit 45. 【0030】 Figure 5 is a cross-sectional view illustrating the cleaning unit 50 shown in Figure 2. As shown in Figures 2 and 5, the cleaning unit 50 comprises a spinner table 51 and a cleaning fluid supply nozzle 52. The spinner table 51 has a structure similar to that of the holding tables 10 and 41, comprising an adsorption portion and a porous portion, and holds the back surface 102 of the first wafer 100, which is placed with its surface 101 facing upward, by suction with its holding surface 53. The spinner table 51 is rotatable around the Z axis by a rotation drive source (not shown). The cleaning fluid supply nozzle 52 supplies cleaning fluid 59 to the surface 101 of the first wafer 100 held on the spinner table 51. The cleaning fluid 59 is, for example, pure water or a mixed fluid of pure water and air. The cleaning unit 50 rotates the spinner table 51 and supplies cleaning liquid 59 to the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100 held on the spinner table 51 using the cleaning liquid supply nozzle 52, thereby performing a cleaning process to clean the first wiring layer 120 with the cleaning liquid 59. 【0031】 The cleaning solution supply nozzle 52 is provided to be movable between a cleaning position in which a cleaning process is performed on the first wafer 100 held on the spinner table 51, and an loading / unloading position in which it is retracted from the spinner table 51 to enable loading the first wafer 100 onto the spinner table 51 and unloading the first wafer 100 from the spinner table 51. 【0032】 As shown in Figure 2, the transport unit 60 includes a first transport section 61, a second transport section 62, a third transport section 63, a fourth transport section 64, and a fifth transport section 65. The first transport section 61 is located in the area between the cassette 73 placed on the cassette mounting table 70, the temporary storage table 75, and the washing unit 50, and transports the first wafer 100 between the cassette 73 placed on the cassette mounting table 70, the temporary storage table 75, and the spinner table 51 of the washing unit 50. The second transport section 62 is movably located between the temporary storage table 75 and the loading / unloading area 17, and transports the first wafer 100 between the temporary storage table 75 and the holding table 10 located in the loading / unloading area 17. 【0033】 The third transport unit 63 is located in an area spanning the loading / unloading area 17 and the processing area 18, and transports the first wafer 100 held on the holding table 10 by moving the holding table 10 between the loading / unloading area 17 and the processing area 18. The fourth transport unit 64 is located so as to be movable between the loading / unloading area 17 and the back surface cleaning unit 30, and transports the first wafer 100 between the holding table 10 located in the loading / unloading area 17 and the back surface cleaning unit 30. The fifth transport unit 65 is located so as to be movable between the back surface cleaning unit 30, the polishing unit 40 and the cleaning unit 50, and transports the first wafer 100 between the back surface cleaning unit 30, the holding table 41 of the polishing unit 40 and the spinner table 51 of the cleaning unit 50. 【0034】 In this manner, the transport unit 60 transports the first wafer 100 between the cassette 73 placed on the cassette mounting table 70, the temporary storage table 75, the outer edge removal unit 20 provided in the processing area 18, the back surface cleaning unit 30, the holding table 41 of the polishing unit 40, and the spinner table 51 of the cleaning unit 50, using the first transport section 61, the second transport section 62, the third transport section 63, the fourth transport section 64, and the fifth transport section 65. 【0035】 The cassette mounting table 70 is a mounting table on which a cassette 73 containing one or more first wafers 100 is placed, and the mounted cassette 73 is raised and lowered in the Z-axis direction. The temporary placement table 75 is a table on which the first wafers 100 removed from the cassette 73 placed on the cassette mounting table 70 are temporarily placed and used for centering the wafers. 【0036】 The control unit 80 controls the operation of each component of the wafer processing system 1 to cause the wafer processing system 1 to perform operational processes such as the outer edge removal step 1001, the polishing step 1002, and the cleaning step 1003 in the wafer processing method according to the embodiment. In this embodiment, the control unit 80 includes a computer system. The computer system included in the control unit 80 includes an arithmetic processing unit having a microprocessor such as a CPU (Central Processing Unit), a storage device having memory such as ROM (Read Only Memory) or RAM (Random Access Memory), and an input / output interface device. The arithmetic processing unit of the control unit 80 performs arithmetic processing according to a computer program stored in the storage device of the control unit 80 and outputs control signals for controlling the wafer processing system 1 to each component of the wafer processing system 1 via the input / output interface device of the control unit 80. 【0037】 In the wafer processing method according to the embodiment, before performing the outer edge removal step 1001, the first transport unit 61 and the second transport unit 62 transport the first wafer 100 from the cassette 73 placed on the cassette mounting table 70, via the temporary storage table 75, onto the holding table 10 located in the loading / unloading area 17. The holding table 10 then holds the first wafer 100 that has been transported onto the holding table 10 by suction with the holding surface 11, and the third transport unit 63 positions the holding table 10 holding the first wafer 100 in the processing area 18. 【0038】 The outer edge removal step 1001 is a step in which the outer edge of the first wafer 100, on which the first wiring layer 120 is formed, is removed from the surface 101. In the outer edge removal step 1001, as shown in Figure 3, the outer edge removal unit 20 performs an outer edge removal process on the first wafer 100, which is held on a holding table 10 positioned in the processing area 18, to form a trimming groove 140 that is deeper than the finished thickness 150. In the outer edge removal step 1001, processing debris is generated when the outer edge of the first wafer 100 is processed from the surface 101 side with the cutting blade 21, and this debris may adhere to the surface 101 of the first wafer 100 (the exposed surface of the first wiring layer 120). 【0039】 In the wafer processing method according to this embodiment, after the outer edge removal step 1001 and before the polishing step 1002, the third transport unit 63 positions the holding table 10, which holds the first wafer 100 with the trimming groove 140 formed in the outer edge removal step 1001, in the loading / unloading area 17, and the fourth transport unit 64 transports this first wafer 100 from the holding table 10 positioned in the loading / unloading area 17 to the back surface cleaning unit 30. The back surface cleaning unit 30 then supports this first wafer 100, which has been transported to the back surface cleaning unit 30, with the wafer support unit 31, and the cleaning unit 32 cleans the back surface 102 side of this first wafer 100, which is supported by the wafer support unit 31. Then, the fifth transport unit 65 transports the first wafer 100, whose back surface 102 side has been cleaned by the back surface cleaning unit 30, from the back surface cleaning unit 30 onto the holding table 41 of the polishing unit 40. This transport is carried out while maintaining the state in which the processing fluid 29 supplied in the outer edge removal step 1001 remains on the surface 101 of the first wafer 100 (the exposed surface of the first wiring layer 120), that is, while maintaining the state in which the first wiring layer 120 is not completely dry. 【0040】 The polishing step 1002 is a step in which the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100 is polished after the outer edge removal step 1001 has been performed. In the polishing step 1002, as shown in Figure 4, the polishing unit 40 performs a polishing process on the first wafer 100 held on the holding table 41. In the polishing step 1002, the amount of polishing of the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100 is in the range of 3 nm to 5 nm. 【0041】 In polishing step 1002, the polishing process is started with the processing fluid 29 supplied in the outer edge removal step 1001 remaining on the surface 101 of the first wafer 100 (the exposed surface of the first wiring layer 120). In polishing step 1002, the polishing process is performed in this manner, so that processing debris adhering to the first wiring layer 120, which is difficult to remove by washing with a mixed fluid of pure water and air, or by washing with a sponge or brush, can be removed. In addition, in polishing step 1002, since the polishing process is started with the processing fluid 29 remaining on the surface 101 of the first wafer 100 (the exposed surface of the first wiring layer 120), the processing debris adhering to the first wiring layer 120 can be suitably removed before it dries and hardens on the first wiring layer 120. 【0042】 Furthermore, in this embodiment, the polishing process performed by the polishing unit 40 in polishing step 1002 is wet polishing using polishing liquid 49 supplied to the processing point by the polishing liquid supply unit 45. Therefore, the polishing liquid 49 removes the abnormal oxidation layer and corrosion layer formed on the exposed surface of the first wiring layer 120, exposing a surface that is not abnormally oxidized or corroded. 【0043】 In the wafer processing method according to this embodiment, after the polishing step 1002 and before the cleaning step 1003, the fifth transport unit 65 transports the first wafer 100, which has undergone polishing in the polishing step 1002, from the holding table 41 of the polishing unit 40 to the spinner table 51 of the cleaning unit 50. 【0044】 The cleaning step 1003 is a step in which the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100 that was polished in the polishing step 1002 is cleaned. In the cleaning step 1003, as shown in Figure 5, the cleaning unit 50 performs a cleaning process on the first wafer 100 held on the spinner table 51 to remove polishing debris and remaining polishing liquid 49 generated in the polishing step 1002 from the surface 101 (exposed surface of the first wiring layer 120) of the first wafer 100. 【0045】 In the wafer processing method according to this embodiment, after the cleaning step 1003 and before the bonding step 1004, the first transport unit 61 transports the first wafer 100, which has undergone cleaning in the cleaning step 1003, from the spinner table 51 of the cleaning unit 50 into a cassette 73 placed on the cassette mounting base 70, and moves this first wafer 100, which has been brought into the cassette 73, to a predetermined bonding apparatus for performing the bonding step 1004. Also, before the bonding step 1004 is performed, a second wafer 200 (see Figure 6) to be bonded with the first wafer 100, which has undergone the outer edge removal step 1001, polishing step 1002, and cleaning step 1003, is prepared. 【0046】 Figure 6 is a cross-sectional view illustrating the bonding step 1004 of Figure 1. The second wafer 200, prepared before the bonding step 1004 is shown in Figure 6, comprises a second substrate 210 and a second wiring layer 220. The second substrate 210 has a flat surface 211 on which the second wiring layer 220 is formed. Thus, the surface 201 of the second wafer 200 is the exposed surface of the second wiring layer 220, and the back surface 202 of the second wafer 200 is the back surface 212 (exposed surface) of the second substrate 210. Preferably, the second wafer 200 is subjected to the same processing as the polishing step 1002 and cleaning step 1003 described above, so that any abnormal oxidation or corrosion layers formed on the exposed surface of the second wiring layer 220 are removed, exposing a surface that is not abnormally oxidized or corroded, and then cleaned. 【0047】 The bonding step 1004 is a step in which the first wafer 100, which has been polished in the polishing step 1002 and whose first wiring layer 120 has been cleaned in the cleaning step 1003, is bonded to the second wafer 200, on which the second wiring layer 220 has been formed on the surface 211 of the second substrate 210. In the bonding step 1004, for example, the first wafer 100 is held from the back surface 102 side, and the second wafer 200 is held from the back surface 202 side, and the exposed surface of the first wiring layer 120 of the first wafer 100 and the exposed surface of the second wiring layer 220 of the second wafer 200 are brought facing each other and aligned in the plane direction, then brought close together, and as shown in Figure 6, the exposed surface of the first wiring layer 120 and the exposed surface of the second wiring layer 220 are brought into contact and bonded. In this way, by joining the first wiring layer 120 and the second wiring layer 220, a bonded wafer 300 is obtained in which the first wafer 100 and the second wafer 200 are bonded together. In bonding step 1004, the exposed surface of the first wiring layer 120 and the exposed surface of the second wiring layer 220 may be directly joined by direct contact, or they may be indirectly joined via an electrically conductive adhesive. By joining the first wiring layer 120 and the second wiring layer 220 in bonding step 1004, the first wiring layer 120 and the second wiring layer 220 become electrically connected. 【0048】 Figure 7 is a cross-sectional view illustrating the back surface grinding step 1005 of Figure 1. The back surface grinding step 1005 is a step in which the back surface 102 of the first wafer 100 is ground to a finished thickness of 150 after the bonding step 1004 has been performed. The back surface grinding step 1005 is performed, for example, by the grinding apparatus 90 shown in Figure 7. 【0049】 The grinding apparatus 90 that performs the backside grinding step 1005 comprises, as shown in Figure 7, a holding table 91, a spindle 92, and a grinding wheel 93 with grinding wheels 94 arranged in an annular shape. The holding table 91 has a structure with a suction part and a porous part similar to the holding tables 10 and 41, and holds the backside 202 side of the second wafer 200 of the bonded wafer 300, which is placed with the backside 102 side of the first wafer 100 facing upward, by suction on the holding surface 96. The holding table 91 is rotatable around the Z axis by a rotation drive source (not shown). The spindle 92 is formed in a cylindrical shape, and a grinding wheel 93 is mounted at its lower end with the grinding wheel 94 facing downward. The spindle 92 rotates around an axis parallel to the Z axis. The spindle 92 is movable in the Z axis direction by a grinding feed unit (not shown). 【0050】 In the back surface grinding step 1005, as shown in Figure 7, the grinding wheel 93 of the grinding device 90 is subjected to rotational motion around an axis parallel to the Z-axis direction by the rotational motion of the spindle 92, and the grinding wheel 94 of the grinding wheel 93 comes into contact with and presses against the back surface 102 side of the first wafer 100 of the bonded wafer 300 held on the holding table 91 below, thereby performing a grinding process in which the first wafer 100 is ground to a finishing thickness of 150 with the grinding wheel 94. 【0051】 Before performing the back grinding step 1005, the outer edge of the first wafer 100 is removed in the outer edge removal step 1001 to form a trimming groove 140 deeper than the finished thickness 150. This prevents the first substrate 110 from forming a sharp edge and chipping when the back grinding step 1005 is performed. 【0052】 The wafer processing system 1 according to the embodiment having the above configuration includes an outer edge removal unit 20 for removing the outer edge of the first wafer 100, a polishing unit 40 for polishing the first wiring layer 120, and a transport unit 60 (third transport unit 63, fourth transport unit 64, and fifth transport unit 65) for transporting the first wafer 100 between the outer edge removal unit 20 and the polishing unit 40. Therefore, the wafer processing method according to the embodiment can be carried out in which the polishing unit 40 polishes the first wiring layer 120 while the processing fluid 29 supplied when the outer edge is removed by the outer edge removal unit 20 remains on the first wiring layer 120 of the first wafer 100. Therefore, the wafer processing system 1 according to the embodiment and the wafer processing method according to the embodiment performed by the wafer processing system 1 according to the embodiment have the effect of being able to suitably remove processing debris adhering to the first wiring layer 120 before the processing debris adhering to the first wiring layer 120 dries and hardens on the first wiring layer 120 when the outer edge is removed, which was difficult to remove by washing performed by supplying a mixed fluid of pure water and air, or by washing using a sponge or brush. As a result, the risk of bonding defects caused by processing debris occurring between the first wiring layer 120 and the second wiring layer 220 of the second wafer 200 can be reduced. 【0053】 Furthermore, in the wafer processing system 1 and wafer processing method according to the embodiment, the polishing process performed by the polishing unit 40 in the polishing step 1002 is wet polishing using polishing liquid 49 supplied to the processing point by the polishing liquid supply unit 45. Therefore, the polishing liquid 49 removes the abnormal oxidation layer and corrosion layer formed on the exposed surface of the first wiring layer 120, exposing a surface that is not abnormally oxidized or corroded. This reduces the risk of bonding defects occurring between the first wiring layer 120 and the second wiring layer 220 of the second wafer 200 due to the abnormal oxidation layer or corrosion layer of the first wiring layer 120. 【0054】 It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core principles of the present invention. [Explanation of Symbols] 【0055】 1. Wafer processing system 10 Retention Table 20. Outer edge removal unit 40 polishing units 44 polishing pads 45 Polishing fluid supply unit 49 Polishing liquid 50 Washing Units 60 transport units 100 First wafer 101,111,201,211 surface 102,112,202,212 Back side 110 First substrate 120 First wiring layer 140 trimming grooves 150 Finishing thickness 200 Second wafer 210 Second substrate 220 Second wiring layer 300 Laminated wafers

Claims

[Claim 1] An outer edge removal step of removing the outer edge portion of a first wafer on which a first wiring layer is formed on the surface, After the outer edge removal step, a polishing step is performed to polish the surface of the first wafer, Equipped with, A wafer processing method characterized in that the polishing step is started while the processing fluid supplied in the outer edge removal step remains on the surface of the first wafer. [Claim 2] The method further includes a bonding step of bonding the first wafer and a second wafer having a second wiring layer formed on its surface, The wafer processing method according to claim 1, characterized in that the first wiring layer and the second wiring layer are joined together in the bonding step. [Claim 3] In the outer edge removal step, the thickness removed from the surface is deeper than the finished thickness of the first wafer. The wafer processing method according to claim 2, further comprising a back surface grinding step of grinding the back surface of the first wafer to a finish thickness after performing the bonding step. [Claim 4] The wafer processing method according to claim 1, characterized in that the polishing step is wet polishing using a polishing solution. [Claim 5] A holding table that holds the back side of a first wafer on which a wiring layer is formed on the surface, An edge removal unit for removing the outer edge from the surface side of a first wafer held on the holding table, A polishing unit for polishing the surface of the first wafer from which the outer edge has been removed by the outer edge removal unit, A cleaning unit for cleaning the first wafer polished by the polishing unit, A transport unit that transports the first wafer between the outer edge removal unit, the polishing unit, and the cleaning unit, Equipped with, The polishing unit is a wafer processing system characterized in that polishing is started while the processing fluid supplied by the outer edge removal unit remains on the surface of the first wafer. [Claim 6] The polishing unit is A polishing pad that contacts the first wafer, A polishing fluid supply unit that supplies polishing fluid to the processing point, A wafer processing system according to claim 5, characterized by comprising the following:

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