Joining method and joining device

Abstract

The bonding method of the present invention includes: a first bonding stage, which is to form a first laminate by releasing the holding of a first substrate and bonding a first substrate and a second substrate; and a second bonding stage, which is to form a second laminate by bonding a thinned one of the bonded first substrate and the second substrate and a third substrate; when the first substrate is thinned, the holding of the third substrate is released in the second bonding stage; when the second substrate is thinned, the holding of the first laminate is released in the second bonding stage.

Description

Technical Field

[0001] This invention relates to a joining method and a joining device. Prior Technology

[0002] There are known methods for forming a multilayer by aligning and joining two substrates that have circuit patterns or the like (see, for example, Patent Document 1). Patent Document 1: Japanese Patent Application Publication No. 2016-213491 Summary of the Invention

[0003] (The problem the invention aims to solve)

[0004] Sometimes, one of the two substrates being joined is a laminate formed by joining multiple substrates. In this case, the strain generated during the formation of the laminate overlaps with the strain generated when the laminate is further joined with other substrates, resulting in an increase in strain in the final laminate. (Solutions)

[0005] The first type of bonding method of the present invention includes: a first bonding stage, which is to form a first laminate by releasing the holding of a first substrate and bonding a first substrate and a second substrate; and a second bonding stage, which is to form a second laminate by bonding a thinned one of the bonded first substrate and the second substrate and a third substrate; when the first substrate is thinned, the holding of the third substrate is released in the second bonding stage; when the second substrate is thinned, the holding of the first laminate is released in the second bonding stage.

[0006] The second aspect of the bonding method of the present invention includes: a first bonding stage, which is to bond a first substrate and a second substrate; and a second bonding stage, which is to bond one of the bonded first substrate and second substrate and a third substrate; in the second bonding stage, the one substrate and the third substrate are bonded in such a way that the positional deviation between the structure of the one substrate that has been strained in the first bonding stage and the structure of the third substrate is less than or equal to a specified size.

[0007] A third embodiment of the present invention provides a bonding method comprising: a first bonding stage in which a first substrate and a second substrate are bonded to form a first laminate; a second bonding stage in which one of the bonded first and second substrates is bonded to a third substrate to form a second laminate; and a determination stage in which a determination is made in the second bonding stage to release the holding of one of the first laminates and the third substrate, such that the positional deviation between the structure of the substrate that has been strained in the first bonding stage and the structure of the third substrate is less than or equal to a specified size.

[0008] The fourth aspect of the bonding method of the present invention includes: a first bonding stage, which is to bond a first substrate and a second substrate; and a second bonding stage, which is to bond one of the bonded first substrate and second substrate and a third substrate; in the second bonding stage, the first substrate and the third substrate are bonded in such a way that the stress distribution generated on the third substrate in the second bonding stage is the same as the stress distribution generated on the first substrate in the first bonding stage.

[0009] The bonding device of the fifth embodiment of the present invention comprises: a bonding portion for bonding: a laminate having a first substrate and a second substrate bonded together, wherein the laminate is thinned on one of the first substrate and the second substrate; and a third substrate; and a receiving portion for receiving and displaying an instruction on whether to release the holding of one of the laminate and the third substrate during bonding; the bonding portion releases the holding of one of the laminate and the third substrate according to the instruction received by the receiving portion, thereby bonding the laminate and the third substrate.

[0010] The sixth aspect of the present invention provides a bonding apparatus comprising: an acquisition unit that acquires information identifying which of the first and second substrates has been thinned when a third substrate is deposited on a first laminate formed by thinning one of the first and second substrates bonded by releasing the holding of the first substrate to form a second laminate; an identification unit that identifies the third substrate when the first substrate has been thinned, and the first laminate when the second substrate has been thinned, based on the information acquired by the acquisition unit; and a bonding unit that releases the holding of the first laminate or the third substrate identified by the identification unit and deposits the first laminate and the third substrate.

[0011] The seventh embodiment of the bonding device of the present invention includes a bonding portion that bonds: a laminate having a first substrate and a second substrate to be bonded, wherein one of the first substrate and the second substrate is thinned; and a third substrate; wherein the bonding portion determines which of the first substrate and the second substrate is thinned during bonding, thereby bonding the laminate and the third substrate.

[0012] The bonding device of the eighth embodiment of the present invention includes a bonding portion, which bonds a first substrate and a second substrate, and bonds one of the bonded first substrate and second substrate and a third substrate. The bonding portion bonds the first substrate and the third substrate in such a way that the positional deviation between the structure of the first substrate that generates strain during the bonding stage of the first substrate and the structure of the third substrate is less than or equal to a specified size.

[0013] The ninth aspect of the present invention provides a bonding device comprising: a bonding portion for bonding a first substrate and a second substrate to form a first laminate, and for bonding one of the bonded first substrate and the second substrate and a third substrate to form a second laminate; and a determination portion for determining whether to release the holding of one of the first laminate and the third substrate when the first substrate and the third substrate are bonded in such a manner that the positional deviation between the structure of the first substrate and the structure of the third substrate, which is strained by the bonding portion, is less than or equal to a specified size.

[0014] The bonding device of the tenth embodiment of the present invention includes a bonding portion that bonds a first substrate and a second substrate, and bonds one of the bonded first substrate and second substrate to a third substrate. The bonding portion bonds the first substrate and the third substrate in such a way that the stress distribution generated on the third substrate by bonding with the first substrate is the same as the stress distribution generated on the first substrate.

[0015] The above summary of the invention is not an exhaustive list of all the features of the invention. Sub-combinations of these features may also constitute inventions. Simple Explanation of the Diagram

[0016] The first figure is a schematic diagram of the substrate stacking device 100. The second figure is a schematic top view of substrate 210. The third figure is a schematic cross-sectional view of the joint 300. The fourth figure shows a flowchart of the operation procedure of the joint 300. The fifth figure is a schematic cross-sectional view showing the movement of the joint 300. Figure 6 is a schematic cross-sectional view showing the movement of the joint 300. Figure 7 is a schematic cross-sectional view showing the movement of the joint 300. Figure 8 is a cross-sectional view of the completed lamellar body 240. Figure 9 shows a flowchart of the manufacturing process for completing the laminate 240. Figure 10 shows a flowchart of the process of identifying the substrate 210 to be released first when bonding the intermediate laminate 230 to the substrate. Figure 11 shows the options table for completing the manufacturing process of laminate 240. Figure 12 shows the strain table of each substrate when the substrates are joined according to the options. Figure 13 shows the interlayer strain table generated on the completed laminate 240 when the substrate is bonded according to the option. Figure 14 shows the bonding process of CIS (CMOS image sensor, CMOS: complementary metal oxide semiconductor) substrate 211 and LOGIC (logic) substrate 212. Figure 15 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 16 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 17 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 18 is a cross-sectional view of intermediate lamination 230. Figure 19 shows a schematic diagram of the strain distribution of the intermediate laminate 230 during the manufacturing process. Figure 20 shows a schematic diagram of the strain distribution in the intermediate laminate 230. Figure 21 shows the bonding process between the intermediate multilayer 230 and the DRAM (Dynamic Random Access Memory) substrate 213. Figure 22 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 23 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 24 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 25 is a cross-sectional view of the completed lamellar body 240. Figure 26 shows a schematic diagram of the nonlinear strain distribution of the completed laminate 240 during the manufacturing process. Figure 27 shows a schematic diagram of the nonlinear strain distribution in the completed laminate 240. Figure 28 shows the magnification strain diagram generated during the bonding process of Example 1. Figure 29 shows the magnification strain diagram generated during the bonding process of Example 1. Figure 30 shows the magnification strain diagram generated during the bonding process of Example 1. Figure 31 shows the magnification strain diagram generated during the bonding process of Example 1. Figure 32 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 33 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 34 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 35 shows the bonding process of CIS substrate 211 and LOGIC substrate 212. Figure 36 is a cross-sectional view of intermediate lamination 230. Figure 37 shows a schematic diagram of the strain distribution of the intermediate laminate 230 during the manufacturing process. Figure 38 is a schematic diagram showing the strain distribution in the intermediate laminate 230. Figure 39 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 40 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 41 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 42 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 43 is a cross-sectional view of the completed lamellar body 240. Figure 44 shows a schematic diagram of the nonlinear strain distribution of the completed laminate 240 during the manufacturing process. Figure 45 shows a schematic diagram of the nonlinear strain distribution in the completed laminate 240. Figure 46 shows a magnification strain diagram of the bonding process in Example 2. Figure 47 shows the magnification strain diagram generated during the bonding process of Example 2. Figure 48 shows the magnification strain diagram generated during the bonding process of Example 2. Figure 49 shows the magnification strain diagram generated during the bonding process of Example 2. Figure 50 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 51 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 52 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 53 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 54 is a cross-sectional view of the completed lamellar body 240. Figure 55 shows a schematic diagram of the nonlinear strain distribution of the completed laminate 240 during the manufacturing process. Figure 56 shows a schematic diagram of the nonlinear strain distribution in the completed laminate 240. Figure 57 shows the magnification strain diagram generated during the bonding process of Comparative Example 1. Figure 58 shows the magnification strain diagram generated during the bonding process of Comparative Example 1. Figure 59 shows the ratio strain diagram generated during the bonding process of Comparative Example 1. Figure 60 shows the ratio strain diagram generated during the bonding process of Comparative Example 1. Figure 61 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 62 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 63 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 64 shows the bonding process between the intermediate laminate 230 and the DRAM substrate 213. Figure 65 is a cross-sectional view of the completed lamellar body 240. Figure 66 shows a schematic diagram of the nonlinear strain distribution of the completed laminate 240 during the manufacturing process. Figure 67 shows a schematic diagram of the nonlinear strain distribution in the completed laminate 240. Figure 68 shows the ratio strain diagram generated during the bonding process of Comparative Example 2. Figure 69 shows the ratio strain diagram generated during the bonding process of Comparative Example 2. Figure 70 shows the magnification strain diagram generated during the bonding process of Comparative Example 2. Figure 71 shows the scaling strain diagram generated during the bonding process of Comparative Example 2. Implementation

[0017] The present invention will now be described through embodiments thereof. These embodiments are not intended to limit the inventors to the scope of the patent application. Not all combinations of the features described in the embodiments are necessary in the invention.

[0018] The first figure is a schematic top view of the substrate stacking apparatus 100. The substrate stacking apparatus 100 includes: a frame 110, substrate boxes 120 and 130 disposed outside the frame 110, a control unit 150, a transport unit 140 disposed inside the frame 110, a joining unit 300, a holder stocker 400, and a pre-aligner 500.

[0019] The substrate holders 120 and 130 can be individually attached to and detached from the frame 110. One substrate holder 120 houses the substrate 210 to be joined later, or a first laminate, i.e., an intermediate laminate 230, formed by joining multiple substrates 210. The other substrate holder 130 houses the intermediate laminate 230, or a second laminate, i.e., a completed laminate 240, formed by joining the substrate 210 and the intermediate laminate 230.

[0020] Here, substrate 210 includes semiconductor wafers such as single-crystal silicon wafers and compound semiconductor wafers, and also includes substrates other than semiconductor wafers such as glass substrates and sapphire substrates. Furthermore, intermediate laminates 230 are deposited on other substrates 210 or other intermediate laminates 230. While finished laminate 240 is a finished product in the lamination process, it further thins the intermediate laminates 230 or substrates 210 located on the surface. In addition, finished laminate 240 is sometimes supplied to downstream processes such as dicing, testing, and packaging.

[0021] Furthermore, the term "bonding of substrates 210" refers to the overlapping of multiple substrates 210 with their main surfaces parallel to each other, and fixing their relative positions with hydrogen bonds, van der Waals bonds, and covalent bonds. Additionally, the term "overlapping substrates 210" refers to a state where the main surfaces of multiple substrates 210 are in contact with each other, but is not limited to a state where their relative positions are fixed. Furthermore, the terms "layering" and "overlapping" are sometimes used interchangeably.

[0022] Furthermore, when bonding substrates 210, the two substrates 210 are aligned with each other before bonding. In particular, substrates 210 that form electronic circuits are precisely aligned in a manner that forms electrical connections with other substrates 210 to which they are bonded.

[0023] The transport unit 140 moves the individual substrate 210, individual substrate holders 221 and 222, intermediate laminate 230, and finished laminate 240 within the frame 110. In addition, the transport unit 140 may also transport the substrate holders 221 and 222 that hold the substrate 210, intermediate laminate 230, and finished laminate 240.

[0024] The control unit 150 controls the operation of each part of the substrate stacking apparatus 100 and coordinates the cooperation between the parts. Furthermore, the control unit 150 may also receive instructions from external users, such as instructions to the bonding part 300 regarding objects like the stacked substrate 210. Moreover, the control unit 150 may also have a user interface such as a display unit that shows the operating status of the substrate stacking apparatus 100 to the outside.

[0025] The joint 300 has a pair of opposing stages, aligning the substrates 210 and intermediate laminates 230 held on each stage. Here, "holding" refers to a state in which force is applied to the substrates 210, restricting their movement. Holding not only restricts the movement of the substrates 210 but sometimes also restricts deformation. Furthermore, "releasing the holding" refers to eliminating the force applied to the substrates 210 for the purpose of holding them.

[0026] Furthermore, the joining portion 300 forms an intermediate laminate 230 by bringing the aligned substrates 210 into contact with each other and joining them. Further, the joining portion 300 joins other substrates 210 on the intermediate laminate 230 to form a completed laminate 240. Details regarding the joining portion 300 will be described later in Figures 3 through 7.

[0027] Furthermore, when the substrate stacking apparatus 100 internally handles the substrate 210, intermediate stack 230, and finished stack 240, it uses substrate holders 221 and 222 housed in the holder storage cabinet 400. The substrate holders 221 and 222 are formed of hard materials such as alumina ceramic and have holding mechanisms such as vacuum chucks and electrostatic chucks. By using these holding mechanisms to hold the substrate 210, the substrate holders 221 and 222 protect the thin and fragile substrate 210, intermediate stack 230, and finished stack 240 from external impacts.

[0028] Furthermore, the substrate holders 221 and 222 hold the substrate 210 and intermediate laminate 230 in place, thereby maintaining the shape of the substrate 210 in accordance with the shape of the holding surfaces of the substrate holders 221 and 222. This allows the substrate 210 and intermediate laminate 230 to remain flat, or to remain deformed according to the shape of the holding surfaces. Unused substrate holders 221 and 222 are stored again in the holder storage cabinet 400 within the substrate stacking apparatus 100 and are not taken outside the substrate stacking apparatus 100 except for maintenance and replacement.

[0029] The pre-aligner 500 cooperates with the conveying section 140 to hold the brought-in substrate 210 in the substrate holders 221 and 222. In addition, the pre-aligner 500 can also be used when separating the intermediate laminate 230 that has been taken out from the joint section 300 from the substrate holders 221 and 222.

[0030] The second figure is a schematic top view showing an example of a substrate 210. The substrate 210 has: a substrate scribe line 217, markings 218, and circuit regions 219. A plurality of markings 218 and a plurality of circuit regions 219 are provided on the surface of the substrate 210.

[0031] Mark 218 is one example of a structure formed on the surface of substrate 210, and the illustrated example shows mark 218 overlapping on substrate cut lines 217 disposed between circuit regions 219. Mark 218 is used at least a portion as an alignment reference when bonding substrate 210 with other substrates 210.

[0032] Each circuit region 219 includes components, wiring, protective films, and other structures formed using photolithography or similar techniques. In addition, the circuit region 219 is also provided with pads, bumps, and other connecting parts that serve as connection terminals when the substrate 210 is electrically connected to other substrates 210, lead frames, etc.

[0033] The third figure is a schematic cross-sectional view showing the structure of the joint 300. The joint 300 shows the state after two substrates 210 have been moved in. The joint 300 includes: a frame 310, a fixed stage 321, and a movable stage 341.

[0034] The frame 310 has a horizontal top plate 311 and a bottom plate 313. The fixed platform 321 is fixed downward to the lower part of the top plate 311 in the figure, and has a holding mechanism for holding the substrate holder 222 that holds the substrate 210. The substrate holder 222 held on the fixed platform 321 is moved into the joint portion 300 with the joint surface of the substrate 210 facing downward in the figure, and is also held downward on the fixed platform 321.

[0035] Furthermore, in the example shown, the substrate holder 222 held on the fixed stage 321 has a shape with a raised center on the adsorption surface of the substrate 210. In this way, the substrate 210 held by the substrate holder 222 is also held in a state with the center raised towards the lower part of the figure, mimicking the shape of the substrate holder 222.

[0036] In the diagram below the top plate 311, the microscope 322 and activation device 323, fixed downwards, are positioned to the side of the fixed stage 321. The microscope 322 can observe the surface of other substrates 210 mounted on a movable stage 341 positioned opposite the fixed stage 321. The activation device 323 generates plasma, for example, to clean or activate the surface of the substrates 210 mounted on the movable stage 341.

[0037] In the diagram of the base plate 313 of the frame 310, an X-direction drive unit 331, a Y-direction drive unit 332, and a moving stage 341 are stacked on top. In the diagram of the moving stage 341, a substrate holder 221 is held on top, which holds the substrate 210. In the illustrated example, the substrate holder 221 has a flat adsorption surface, and the substrate 210 held in the substrate holder 221 is held in a flat state.

[0038] The X-direction drive unit 331 moves parallel to the base plate 313 in the direction indicated by arrow X in the figure. The Y-direction drive unit 332, on top of the X-direction drive unit 331, moves parallel to the base plate 313 in the direction indicated by arrow Y in the figure. By combining the actions of the X-direction drive unit 331 and the Y-direction drive unit 332, the moving platform 341 moves in a plane (two-dimensional) parallel to the base plate 313.

[0039] A Z-direction drive unit 333 is further disposed between the Y-direction drive unit 332 and the moving platform 341. The Z-direction drive unit 333 moves the moving platform 341 relative to the Y-direction drive unit 332 in the direction perpendicular to the base plate 313, as indicated by arrow Z. This causes the moving platform 341 to rise and fall. The movement of the moving platform 341 is precisely controlled using an interferometer or similar device by means of the X-direction drive unit 331, the Y-direction drive unit 332, and the Z-direction drive unit 333.

[0040] In the diagram above the Y-direction drive unit 332, a microscope 342 and an activation device 343 are mounted on the side of the movable stage 341. The microscope 342 moves together with the Y-direction drive unit 332 to observe the underside of the substrate 210 held on the fixed stage 321. The activation device 343 moves together with the Y-direction drive unit 332 and, similar to the previously described activation device 323, generates, for example, plasma irradiating the substrate 210 to purify or activate the underside of the substrate 210 held on the fixed stage 321.

[0041] Furthermore, the activation of substrate 210 includes the following: in order to form a solid bond without melting, at least one substrate's bonding surface is treated to create hydrogen bonds, van der Waals bonds, and covalent bonds when the bonding surface of substrate 210 contacts the bonding surface of other substrates 210. That is, activation includes forming dangling bonds on the surface of substrate 210 to facilitate bonding.

[0042] More specifically, activation devices 323 and 343, for example, plasmaify oxygen (used as a processing gas) under reduced pressure and irradiate it with oxygen ions onto the surfaces of the two substrates that serve as bonding surfaces. For example, if the substrate is a silicon (Si) substrate with a silicon oxide (SiO) film formed on it, irradiation with oxygen ions breaks the bonds of silicon oxide on the substrate surfaces that serve as bonding surfaces during lamination, thus forming dangling bonds between silicon (Si) and oxygen (O). Sometimes, forming such dangling bonds on the surface of substrate 210 is called activation.

[0043] When a substrate with dangling bonds is exposed to the atmosphere, moisture in the air combines with these dangling bonds, and the substrate surface is covered with hydroxyl groups (OH groups). The substrate surface becomes readily hydrophilic, readily combining with water molecules. In other words, activation results in a readily hydrophilic substrate surface. Furthermore, during solid-state bonding, impurities such as oxides and defects at the bonding interface can affect the bonding strength. Therefore, cleaning the bonding surface can also be considered part of the activation process.

[0044] In addition to free radical irradiation using DC plasma, RF plasma, or MW-excited plasma, methods for activating substrate 210 include sputtering etching using inert gases, ion beams, and high-speed atomic beams. Furthermore, activation methods using ultraviolet irradiation or ozone ashing are also examples. Moreover, chemical purification treatment using liquid or gaseous etchants is also an example.

[0045] Furthermore, a hydrophilization device (not shown) can be used to hydrophilize the surface of substrate 210 by coating the surface of substrate 210, which becomes the bonding surface, with pure water or the like. The surface of substrate 210 becomes a state where OH groups are attached, i.e., a state where OH groups are the terminals, due to this hydrophilization. Alternatively, other activation devices, replacing activation devices 323 and 343, can be placed at a different position than the bonding portion 300, and the pre-activated substrate 210 can be moved into the bonding portion 300.

[0046] The joint 300 further includes a control unit 150. The control unit 150 controls the operation of the X-direction drive unit 331, the Y-direction drive unit 332, the Z-direction drive unit 333, the activation device 323, and the activation device 343.

[0047] Furthermore, before bonding the substrate 210, the control unit 150 pre-calibrates the relative positions of the microscopes 322 and 342. The calibration of the microscopes 322 and 342 can, for example, involve focusing the microscopes 322 and 342 on a common focal point F, and this is performed by observing each other. Additionally, the microscopes 322 and 342 can also observe common standard indicators.

[0048] Figure 4 is a flowchart showing the procedure for performing one bonding operation using the bonding member 300. Furthermore, Figures 5 through 7 are schematic cross-sectional views showing the operation of the bonding member 300 at each stage. The illustration is based on an example where the bonding objects are two substrates 210; however, the bonding objects can also be substrate 210 and an intermediate laminate 230. Moreover, when bonding the substrates 210, substrates 210 with the same structure can be bonded, as can substrates with different structures.

[0049] First, the control unit 150 instructs the transport unit 140 to move the two substrates 210, which will be the objects of bonding, into the bonding unit 300 (step S101). Next, as shown in Figure 5, the control unit 150 uses microscopes 322 and 342 and a moving stage 341 to measure the position of the mark 218 on the substrate 210 (step S102). That is, by moving the moving stage 341, a specific position of the field of view of the microscopes 322 and 342 is aligned with the mark 218. Since the position of the microscope 322 and the initial position of the microscope 342 are known, the control unit 150 can measure the absolute position of the mark 218.

[0050] Next, the control unit 150 calculates the relative position of the substrate 210 based on the position of the mark 218 obtained in step S102 (step S103). Further, the control unit 150 calculates the amount of movement required for the moving stage 341 to align the substrate 210 based on the calculated relative position of the substrate 210. The amount of movement required for alignment is calculated, for example, using known methods such as EGA (Enhanced Global Alignment), to determine the amount of movement of the moving stage 341 in the x and y directions and the rotation angle θ. Thus, the control unit 150 can align the substrate 210 using the identified mark 218 as a reference.

[0051] Next, while maintaining the information on the amount of movement of the substrate 210 calculated for alignment, the control unit 150 activates the bonding surface of the substrate 210 by simultaneously moving the moving stage 341 while activating the activation devices 323 and 343, and by scanning the surface of the substrate 210 with plasma (step S104). After activation, the surface of the substrate 210 is in a state of bonding by contact without any inclusions such as adhesives, or without any processing such as welding or pressing.

[0052] Next, the control unit 150 moves the moving stage 341 according to the relative position calculated in step S103, and as shown in Figure 6, aligns the substrates 210 with each other (step S105). Further, as shown in Figure 7, the control unit 150 activates the Z-direction drive unit 333 to raise the moving stage 341.

[0053] In this way, shortly after the substrate 210 rises, a portion of the substrate 210 protruding downwards, held on the fixed stage 321, comes into contact with a portion of the substrate 210 held on the movable stage 341. The substrates 210, whose surfaces were activated in step S106, are bonded in the contact area by hydrogen bonds, van der Waals bonds, and covalent bonds. Furthermore, the entire substrate 210 is released from its holding position, and the bonding area is expanded by the adsorption force of the substrate 210 itself. Soon, the substrates 210 are almost completely bonded, forming an intermediate laminate 230 consisting of two bonded substrates 210 (step S106).

[0054] The intermediate laminate 230 thus formed is removed from the joint 300 (step S107). Furthermore, after the intermediate laminate 230 is separated from the substrate holder 221, it is housed in the substrate box 130.

[0055] In addition, when the two substrates 210 are hydrogen bonded together by contact with each other, after the intermediate laminate 230 is formed, covalent bonds can be generated between the substrates 210 by heating the intermediate laminate 230 in a heating device such as an annealing furnace. This can improve the bonding strength between the substrates 210.

[0056] Next, the control unit 150 checks from the substrate cassette 120 whether there are no more substrates 210 that need to be bonded (step S108). If there are still substrates 210 that need to be bonded (step S108: NO), the control unit 150 returns the program to step S101 and repeats the series of bonding procedures from steps S102 to S108. If it is determined in step S108 that there are no more substrates 210 that need to be bonded (step S108: YES), the control unit 150 ends the control of the substrate stacking apparatus 100.

[0057] Furthermore, the above example holds the substrate holder 222, which has a centrally raised adsorption surface, on the fixed stage 321. However, the substrate holder 222 can also be held on the movable stage 341. In addition, the adsorption surface of the substrate holder 222, used for the purpose of contacting a portion of the mating surface of the substrate 210, can have a curved shape overall, or it can have local protrusions. Furthermore, the substrate 210 can be partially contacted by pushing it through other components penetrating the substrate holder 222.

[0058] Furthermore, in the above example, two substrates 210 are joined to form an intermediate laminate 230. However, the intermediate laminate 230 is further joined with other substrates 210 using a joining portion 300 to form a finished laminate 240.

[0059] Figure 8 is a cross-sectional view showing a specific example of the final form of the completed stacked assembly 240. The completed stacked assembly 240 is a stacked image sensor having a CIS (CMOS image sensor, CMOS: Complementary Metal-Oxide-Semiconductor) substrate 211, a LOGIC substrate 212, and a DRAM substrate 213 sequentially bonded together. Here, the CIS substrate 211, the LOGIC substrate 212, and the DRAM substrate 213 are each an example of a separate substrate 210 to be stacked.

[0060] The CIS substrate 211 has a large number of light-receiving elements arranged in a planar, high-density configuration. It is a light-receiving element substrate that converts externally incident image light into electrical signals and outputs them. The LOGIC substrate 212 is a processing substrate that performs digital conversion and other processes on the electrical signals output from the CIS substrate 211 to convert them into image signals. Furthermore, the DRAM substrate 213 is a memory substrate that acts as a buffer. This buffer has a large number of memory cells that temporarily store the image signals generated by the LOGIC substrate 212, thereby mitigating the speed difference between the processing speed of the CIS substrate 211 and the LOGIC substrate 212 and the speed difference between the secondary memory medium that records the image signals.

[0061] The completed laminate 240 is formed by first forming an intermediate laminate 230 using a CIS substrate 211 and a LOGIC substrate 212, and then depositing the intermediate laminate 230 and the DRAM substrate 213. In addition, in the completed laminate 240 shown in the figure, the CIS substrate 211 and the LOGIC substrate 212 are thinned and are thinner than when they were bonded.

[0062] Figure 9 shows a flowchart of the manufacturing process of the completed laminate 240. First, the control unit 150 obtains information about the first manufactured completed laminate 240 (step S201).

[0063] The information obtained here includes information for identifying which layer will be thinned during the fabrication of the laminate 240, formed by the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213. Therefore, the control unit 150 can be said to function as an acquisition unit for obtaining information for identifying which layer will be thinned during the fabrication of the laminate 240, formed by the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213. Furthermore, the information obtained by the control unit 150 may also include information for identifying which layer's holding is released during the bonding process when the CIS substrate 211 and LOGIC substrate 212 are joined to form the intermediate laminate 230.

[0064] Next, based on the information obtained in step S201, the control unit 150 identifies which one to release when bonding the intermediate laminate 230 and the DRAM substrate 213 (step S202). The identification method will be described later in Figure 10.

[0065] Next, the control unit 150 joins the CIS substrate 211 and the LOGIC substrate 212 in the joining unit 300 according to the procedure shown in Figure 4 (step S203). Then, it instructs a thinning device, such as a mechanical-chemical polishing device disposed outside the substrate stacking apparatus 100, to thin the LOGIC substrate 212 (step S204). Thus, the first joining stage in the manufacturing of the stack 240 is completed, and the intermediate stack 230 is formed (step S205).

[0066] Here, the control unit 150 checks from the substrate holder 120 whether there is no CIS substrate 211 or LOGIC substrate 212 left (step S206). If both CIS substrate 211 and LOGIC substrate 212 are retained (step S206: No), the control unit 150 returns the program to step S203 and repeats the series of bonding procedures from steps S203 to S205. In step S206, if it is determined that there is no substrate 210 that needs to be bonded (step S206: Yes), the control unit 150 ends the first bonding in the bonding unit 300 and begins the second bonding as described below.

[0067] In the second bonding process, the control unit 150 bonds the intermediate multilayer 230 and the DRAM substrate 213 according to the procedure shown in Figure 4. First, the control unit 150 thins the intermediate multilayer 230 formed by the CIS substrate 211 and the LOGIC substrate 212 in the bonding section 300, that is, bonds the DRAM substrate 213 to the LOGIC substrate (step S207). In this bonding process, the control unit releases the holding of the intermediate multilayer 230 or the DRAM substrate 213 identified in step S202, so that bonding can be performed.

[0068] Next, the control unit 150 instructs a thinning device disposed outside the substrate stacking apparatus 100 to thin the CIS substrate 211 (step S208). Thus, the second bonding stage in the fabrication of the stacked body 240 is completed, and the completed stacked body 240 of the stacked image sensor is formed (step S209).

[0069] Next, the control unit 150 checks from the substrate cassette 120 whether there is no intermediate laminate 230 or DRAM substrate 213 remaining (step S210). If both the intermediate laminate 230 and DRAM substrate 213 are retained (step S210: No), the control unit 150 returns the program to step S207 and repeats the series of bonding procedures from steps S207 to S209. In step S210, if it is determined that the substrate 210 does not need to be bonded (step S210: Yes), the control unit 150 ends the second bonding in the bonding unit 300.

[0070] Figure 10 shows a flowchart of the control procedure for identifying the substrate to be released in step S202 above. First, the control unit 150 checks the procedure set for the first bonding based on the information obtained in step S201 to see if the substrate to be released in step S203 in CIS substrate 211 and LOGIC substrate 212 is the substrate to be thinned in step S204 (step S211).

[0071] In step S211, when it is determined that the holding of the LOGIC substrate 212 is released (step S211: Yes), the control unit 150 identifies the substrate released from holding in the second bonding as not being the intermediate stack 230, i.e., the DRAM substrate 213 (step S212). Furthermore, in step S211, when it is determined that the holding of the LOGIC substrate 212 is not released (step S211: No), the control unit 150 identifies the substrate released from holding in the second bonding as the intermediate stack 230 (step S213). In this case, the control unit 150 can be said to function as an identification unit that identifies the DRAM substrate 213 when the substrate in the first bonding is thinned, and identifies the intermediate stack 230 when the substrate in the first bonding is not thinned. The reason for identifying the substrate released from holding first in the second bonding using this procedure is explained below.

[0072] Furthermore, in the example described above, the control unit 150 has designated the substrate to be released first during the second bonding process according to the procedure shown in Figure 10. However, the control unit 150 can also receive the designation of the side to be released first during bonding from an external source. In other words, as long as the bonding section 300 allows the side to be released first during bonding, the following method can be performed even if it is not a dedicated device. In this case, the control unit 150 can be said to function as a receiving unit that receives instructions on whether to release the holding of the intermediate laminate 230 or the DRAM substrate 213 during bonding.

[0073] Figure 11 shows an option table for completing the manufacturing process of the laminate 240. When the laminate 240 is manufactured using the bonding part 300 under the control of the control unit 150, as shown in Figure 11, there are four specific combinations in which the substrate to be held is released first in the first bonding and the second bonding.

[0074] Furthermore, during the manufacturing process of the completed laminate 240 shown in Figure 8, the CIS substrate 211 is thinned after the DRAM substrate 213 is deposited on the intermediate laminate 230. Through this process, the LOGIC substrate 212 can be thinned using the CIS substrate 211 as a support before the DRAM substrate 213 is deposited on the intermediate laminate 230. Therefore, the process of attaching an additional support for thinning the LOGIC substrate 212 can be omitted. Thus, even in the assembly shown in Figure 11, the LOGIC substrate 212 is thinned in step S204 of the process shown in Figure 9, and the CIS substrate 211 is thinned in step S208 of the second bonding.

[0075] Figure 12 shows the strain appearing in each layer of the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213 when the laminate 240 is formed using the assembly process shown in Figure 11. Here, strain 1 refers to the relative difference in strain generated during the bonding process of the CIS substrate 211 and LOGIC substrate 212 bonded in the first bonding. Furthermore, strain 2 refers to the relative difference in strain generated during the bonding process of the intermediate laminate 230 and DRAM substrate 213 bonded in the second bonding. Strain 1' refers to the strain distribution along the Y-axis of the substrate surface that is reversed from strain 1 when the LOGIC substrate 212 is bonded in the second bonding by reversing the bonding process compared to the first bonding.

[0076] Furthermore, both strain 1 and strain 2 mentioned above refer to the strain of the substrate that is released from holding, with the sign of positive. When strain 1 and strain 2 are generated on the substrate that is held without being released during the bonding of CIS substrate 211 and LOGIC substrate 212, or LOGIC substrate 212 and DRAM substrate 213, and the strain is so small as to be negligible, then they are approximately equal to the strain generated on the substrate that is released from holding. In other words, strain 1 and strain 2 are the result of thinning after bonding the substrates in the first or second bonding process, and are the strains retained on the thinned substrate.

[0077] Furthermore, Figure 13 shows a table illustrating the interlayer strain differences generated on the completed laminate 240 when bonding is performed using the combination shown in Figure 11. Here, "layer" refers to the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213 that form the completed laminate 240. The strain generated in the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213 bonded to complete the laminate 240 is distributed according to the rigidity of each substrate.

[0078] Furthermore, the aforementioned strain corresponds to the stress distribution in each of the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213. The stress generated in the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213 causes deformation of the CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213 when the substrate holder 221 and the like release the restraint on the substrate, and causes the structures provided on each substrate to change position from the design coordinates, that is, from the design position.

[0079] In this embodiment, the strain generated by each substrate 210, including the CIS substrate 211, the LOGIC substrate 212, and the DRAM substrate 213, includes: plane strain and three-dimensional strain. Furthermore, the plane strain on the substrate 210 may include: magnification strain and orthogonal strain.

[0080] The rate strain is the linearly increasing strain in a certain diameter direction, measured from the center of the structure on substrate 210, representing the displacement of the structure from the center of substrate 210. When two substrates 210 are laminated, the rate strain generated by each substrate 210 is reflected in the positional deviation between the substrates 210. The value of the rate strain is obtained by dividing the deviation measured from a designed position at a distance r from the center of substrate 210 by the distance r, and the unit is ppm.

[0081] Furthermore, the rate strain includes both isotropic rate strain and anisotropic rate strain. When the rate strain is isotropic, the X and Y components of the displacement vector of the structure caused by the strain are equal. Therefore, when isotropic rate strain occurs, the rate change in the X direction of the substrate 210 is equal to the rate change in the Y direction. When the rate strain is anisotropic, the X and Y components of the displacement vector from the designed position of the structure are different, and the rate of increase in the X direction of the substrate 210 is different from the rate of increase in the Y direction.

[0082] Furthermore, plane strain can be classified into linear strain and nonlinear strain. Linear strain is the strain that, through linear transformation, represents the position of a structure on substrate 210 after it has changed position from its designed location due to strain. Nonlinear strain is strain that cannot be represented by linear transformation. Regarding the aforementioned scaling factor strain, anisotropic scaling factor strain is classified as nonlinear strain. Nonlinear strain is generated, for example, by the anisotropy of the crystal structure of substrate 210 and by the processing during the manufacturing process of substrate 210. In addition, nonlinear strain can sometimes also be generated by the rigid distribution of the arrangement of structures formed on substrate 210.

[0083] The orthogonal strain generated on the substrate 210 as plane strain is the strain caused by the structure changing position from its designed position in a direction parallel to the X-axis when an orthogonal coordinate system XY is set with the center of the substrate as the origin. The strain increases with distance from the origin along the Y-axis. Furthermore, the displacement caused by the orthogonal strain is equal in multiple regions that span the Y-axis parallel to the X-axis, and the absolute value of the displacement increases with distance from the X-axis. Additionally, the displacement caused by the orthogonal strain has opposite directions on the positive and negative sides of the Y-axis.

[0084] The aforementioned planar strain results in a three-dimensional strain in the substrate 210 that causes structural displacement in the direction intersecting the surface of the substrate 210, and manifests as bending of the substrate 210. Here, bending refers to distortion of the entire substrate 210 or a localized area. Distortion refers to a change in shape on the surface of the substrate 210 that includes points not existing on the plane defined by the three points on the surface of the substrate 210.

[0085] Furthermore, the strain that forms a curved surface on the bending substrate 210 includes warping. Warping refers to the strain remaining on the substrate 210 after removing the influence of gravity on the strain. When gravity causes warping, the distorted strain on the substrate 210 is referred to as flexure in this embodiment. Warping includes overall warping where the entire substrate 210 buckles with approximately the same curvature, and localized warping where a portion of the substrate 210 buckles due to a change in curvature.

[0086] The aforementioned rate strain can be classified according to its cause into initial rate strain, adsorption rate strain, and bonding process rate strain.

[0087] The initial rate strain is the strain that has already occurred in each substrate 210 before the stacking stage, and it occurs due to periodic rigidity changes caused by the arrangement of substrate dicing lines 217, circuit regions 219, etc. The initial rate strain reflects the deviation of the position of the structure on the substrate 210 from the designed position in the substrate 210. The initial rate strain can be known before the stacking of the substrate 210 begins. Information on the initial rate strain can also be obtained by measuring the substrate 210 just before stacking, or by obtaining information measured during the manufacturing stage of the substrate 210 during the stacking stage.

[0088] The adsorption ratio strain refers to the strain generated when the shape of the substrate 210 differs from the shape of the adsorption surface of the holding members such as the substrate holders 221 and 222 that hold the substrate 210. When the holding members adsorb the substrate 210 using holding mechanisms such as electrostatic chucks or vacuum chucks, the substrate 210 becomes shaped to mimic the adsorption surface of the holding members. Therefore, when the shape of the substrate 210 differs from the shape of the adsorption surface of the holding members, the substrate 210 deforms due to being adsorbed onto the holding members, resulting in a change in its strain state.

[0089] Furthermore, when the magnitude of the adsorption ratio strain causes warping or other strains on the substrate 210, the strain can be calculated from the state of strain, including the amount and shape of warping of the substrate 210, by checking the relationship between the strain and the adsorption ratio strain in advance. Therefore, by preparing multiple holding members with different adsorption surface shapes, the adsorption ratio strain can be actively utilized when correcting the strain of the substrate 210 by adjusting the shape of the adsorption surface.

[0090] The bonding process ratio strain refers to the ratio strain newly generated during the bonding process by overlapping and bonding the substrates 210. When bonding the substrates 210, the bonding of the substrates 210 begins to expand from a portion of the bonding surface and eventually extends to approximately the entire substrate 210. Therefore, during the bonding process, at least one of the substrates 210 deforms near the boundary between the area that has been bonded and is in close contact with the other substrate and the area that is not in contact with the other substrate but is subsequently bonded. A portion of this deformation becomes the bonding process ratio strain by bonding and fixing the substrates 210 together.

[0091] Among the various strains of the substrate 210, even when the substrate 210 is reversed for bonding, the strain distribution on the bonding surface remains unchanged. In addition, for example, the strain distribution during the bonding process is the same as the pattern distributed according to the bonding procedure, and it is possible to control whether positive or negative strain is generated.

[0092] Figures 14 through 18 show nonlinear strain patterns generated on the CIS substrate 211 and the LOGIC substrate 212 during the first bonding process when the procedure of Embodiment 1 shown in Figure 11 is performed. As shown in Figure 11, Embodiment 1 first releases the holding of the LOGIC substrate 212 during the first bonding. In Embodiment 1, the LOGIC substrate 212 is the first substrate, and the CIS substrate 211 is the second substrate.

[0093] As shown in Figure 14, during the time when the LOGIC substrate 212 is released from holding and bonded, the CIS substrate 211 is adsorbed by the substrate holder 221 with a flat adsorption surface and fixed in a flat state.

[0094] Therefore, as shown in Figure 15, during the bonding stage of the CIS substrate 211 and the LOGIC substrate 212, the strain generated by bonding occurs in the LOGIC substrate 212, which is released from holding before the CIS substrate 211. Secondly, as shown in Figure 16, when the CIS substrate 211 is released from holding by the substrate holder 221, the stress generated in the layer of the LOGIC substrate 212 causes the bonded CIS substrate 211 and LOGIC substrate 212 to undergo deformation accompanied by warping, and the CIS substrate 211 and LOGIC substrate 212 generate strains in opposite directions.

[0095] Then, as shown in Figure 17, the CIS substrate 211 is attached to the flat substrate holder 223, which serves as a thinning jig, forcibly planarizing the CIS substrate 211 and the LOGIC substrate 212. This causes the bonded CIS substrate 211 and LOGIC substrate 212 to distribute strain according to their rigidity. Furthermore, as shown in Figure 18, when the substrate holder 223 is released from holding the intermediate laminate 230 formed by thinning the LOGIC substrate 212, the strain of the intermediate laminate 230 as a whole is biased towards the layer of the LOGIC substrate 212, whose rigidity has decreased due to thinning, and the strain of the CIS substrate 211 is significantly reduced.

[0096] Figure 19, as shown in Figure 15, is a schematic top view showing the distribution of nonlinear strain while the bonded CIS substrate 211 and LOGIC substrate 212 are held in the substrate holder 221. Furthermore, Figure 20 is a schematic top view showing the distribution of nonlinear strain in the intermediate laminate 230 shown in Figure 18. Comparing Figures 19 and 20, it is clear that much of the strain generated in the LOGIC substrate 212 by the first bonding is transferred to the LOGIC substrate 212 within the intermediate laminate 230.

[0097] Figures 21 to 25 show the nonlinear strain patterns generated in each layer of the CIS substrate 211 and LOGIC substrate 212 in the intermediate laminate 230 and in the DRAM substrate 213 during the second bonding process when performing the procedure of Embodiment 1 shown in Figure 11. As shown in Figure 11, in Embodiment 1, the holding of the DRAM substrate 213 is released first during the second bonding. The DRAM substrate 213 in Embodiment 1 is the third substrate.

[0098] As shown in Figure 21, when the DRAM substrate 213 is released from its holding position and bonding begins, the adsorption surface of the intermediate stack 230 is adsorbed onto the flat substrate holder 221 and fixed in a flat state. Therefore, as shown in Figure 22, during the bonding stage of the intermediate stack 230 and the DRAM substrate 213, the bonding strain is generated on the side of the DRAM substrate 213. However, at least a portion of this strain, as shown in Figure 18, is a strain of the same shape as the strain generated on the layer of the LOGIC substrate 212 of the intermediate stack 230. This reduces the positional deviation caused by the difference between the strain generated on the LOGIC substrate 212 and the strain generated on the DRAM substrate 213.

[0099] At this time, the strain generated in the DRAM substrate 213 and the strain generated in the layer of the LOGIC substrate 212 of the intermediate stack 230 can be of the same shape strain. Based on the information related to the strain generated in the DRAM substrate 213 when the intermediate stack 230 and the DRAM substrate 213 are joined in the second bonding, the bonding conditions for joining the CIS substrate 211 and the LOGIC substrate 212 in the first bonding can be determined. In addition, the bonding conditions for joining the intermediate stack 230 and the DRAM substrate 213 in the second bonding can also be determined based on the information related to the strain when the CIS substrate 211 and the LOGIC substrate 212 are joined in the first bonding.

[0100] The strain occurring on the LOGIC substrate 212 during the formation of the intermediate stack 230 and the strain occurring on the DRAM substrate 213 during the bonding of the intermediate stack 230 and the DRAM substrate 213 are strains that occur for the same reason. When the strain directions are the same, the positional deviation caused by the difference between the strain of the LOGIC substrate 212 and the strain of the DRAM substrate 213 of the intermediate stack 230 is reduced.

[0101] In the above example, at least the bonding process ratio strain generated during the bonding stage of the CIS substrate 211 and LOGIC substrate 212 forming the intermediate laminate 230, and the bonding process ratio strain generated during the bonding stage of the intermediate laminate 230 and DRAM substrate 213, are equivalent to strains of the same shape. Furthermore, even if the strains are generated from the same cause, but have the same sign (i.e., different directions), the difference in strain between the LOGIC substrate 212 and the DRAM substrate 213 is doubled compared to when the DRAM substrate 213 has no strain. Therefore, the positional deviation between the DRAM substrate 213 and the LOGIC substrate 212 increases in the completed laminate 240.

[0102] Secondly, as shown in Figure 23, when the substrate holder 221 is released, the stress generated on the DRAM substrate 213 causes the intermediate laminate 230 to warp along with the substrate. Consequently, the intermediate laminate 230 also warps along with the DRAM substrate 213. At this time, the CIS substrate 211 and LOGIC substrate 212 forming the intermediate laminate 230 experience strains opposite to those on the DRAM substrate 213.

[0103] Then, as shown in Figure 24, when the surface of the DRAM substrate 213 is attached to the substrate holder 223, which serves as a thinning jig, and the intermediate stack 230 is forcibly planarized, the bonded intermediate stack 230 and DRAM substrate 213 are subjected to strain according to rigidity. Furthermore, as shown in Figure 25, the rigidity of the thinned CIS substrate 211 decreases. Therefore, when the substrate holder 223 releases the holding of the completed stack 240, the strain distributed on the LOGIC substrate 212 and DRAM substrate 213 increases, while the strain on the DRAM substrate 213 decreases. The illustrated example is because the nonlinear strain generated in the LOGIC substrate 212 and DRAM substrate 213 is of the same shape, so the portion of the LOGIC substrate 212 corresponding to the portion of the DRAM substrate 213 that shrinks or amplifies due to release undergoes an equal amount of shrinkage or amplification deformation, thus relieving the nonlinear strain of the LOGIC substrate 212. Furthermore, because the nonlinear strain generated in the CIS substrate 211 has a different shape than the nonlinear strain generated in the DRAM substrate 213, the CIS substrate 211 is further deformed in the direction of the shrinking or amplifying deformation of the DRAM substrate 213 due to release.

[0104] Figure 26, as shown in Figure 22, is a schematic top view showing the distribution of nonlinear strain while the bonded intermediate laminate 230 and DRAM substrate 213 are held in the substrate holder 221. The state shown in Figure 26 is such that the strain generated by the first bonding is generated in the LOGIC substrate 212, and the strain generated by the second bonding is generated in the DRAM substrate 213.

[0105] Figure 27 is a top view schematically showing the distribution of nonlinear strain in the completed laminate 240 shown in Figure 25, and illustrates the state in which the strain of the DRAM substrate 213 is distributed between the CIS substrate 211 and the DRAM substrate 213 by thinning the CIS substrate 211. At this time, the strain distributed in the CIS substrate 211 is opposite to that in the DRAM substrate 213. Therefore, the strain generated during the first bonding in the LOGIC substrate 212 is offset, and the strain generated in the CIS substrate 211 is opposite to that in the DRAM substrate 213.

[0106] Figures 28 to 31 illustrate the scaling strain generated during the bonding process of Embodiment 1. In Figures 28 to 31, the arrows with hollow arrowheads pointing outwards at both ends of a straight line indicate that the spacing between structures on the substrate has increased, resulting in a scaling strain that expands the substrate outwards along the radial direction of the substrate. Conversely, when a pair of arrows with opposing arrowheads are shown, it indicates that the spacing between structures on the substrate has narrowed, resulting in a scaling strain that decreases the substrate outwards along the radial direction of the substrate towards the center, resulting in a scaling strain that shrinks the substrate.

[0107] When the CIS substrate 211, which is held in the substrate holder 221, is bonded to the LOGIC substrate 212, which is first released from holding, a bonding process ratio strain is generated on the LOGIC substrate 212 due to the deformation caused by the bonding process. The bonding process ratio strain of the LOGIC substrate 212 is an isotropic linear strain, and as shown in Figure 28, it is a strain in which the amount of deformation in the radial direction of the LOGIC substrate 212 increases linearly outward.

[0108] Continuing, when the LOGIC substrate 212 of the CIS substrate 211 and LOGIC substrate 212 is thinned, the rate strain of the LOGIC substrate 212, which has reduced rigidity due to thinning, has almost no effect on the CIS substrate 211. Therefore, in the intermediate laminate 230 formed by bonding the CIS substrate 211 and LOGIC substrate 212, the rate strain generated in the LOGIC substrate 212 is still retained in the LOGIC substrate 212 as shown in Figure 29.

[0109] Secondly, when the DRAM substrate 213 is bonded to the intermediate laminate 230 held in the substrate holder 221, a bonding process rate strain is generated on the DRAM substrate 213 that has been released from holding. The rate strain on the DRAM substrate 213, like the rate strain generated on the LOGIC substrate 212, is a strain resulting from a linear increase in the radial outward deformation of the DRAM substrate 213. As shown in Figure 30, a bonding process rate strain has already been generated on the LOGIC substrate 212, which is in contact with the DRAM substrate 213 in the intermediate laminate 230. Therefore, a positional deviation caused by the bonding process rate strain occurs between the bonded DRAM substrate 213 and the LOGIC substrate 212.

[0110] Continuing, as shown in Figure 31, when the CIS substrate 211 is thinned, the rate strain of the LOGIC substrate 212 and DRAM substrate 213 is concentrated on the CIS substrate 211, roughly eliminating the rate strain of the LOGIC substrate 212 and DRAM substrate 213. However, although the rate strain in the opposite direction to that generated in the DRAM substrate 213 is generated in the CIS substrate 211, the already bonded CIS substrate 211, LOGIC substrate 212, and DRAM substrate 213 will not have positional deviations between them.

[0111] Figures 32 to 36 show the nonlinear strain generated in the CIS substrate 211 and LOGIC substrate 212 during the first bonding process when performing the procedure of Embodiment 2 shown in the table of Figure 11. As shown in Figure 11, in Embodiment 2, the holding of the CIS substrate 211 is released first during the first bonding. The CIS substrate 211 in Embodiment 2 is the first substrate, and the LOGIC substrate 212 is the second substrate.

[0112] As shown in Figure 32, when the CIS substrate 211 is released and bonding begins, the LOGIC substrate 212 is adsorbed onto the substrate holder 221 with a flat adsorption surface and fixed in a flat state.

[0113] Therefore, as shown in Figure 33, during the bonding stage of the CIS substrate 211 and the LOGIC substrate 212, the strain generated by the bonding is generated in the CIS substrate 211. Secondly, as shown in Figure 34, when the substrate holder 221 is released, the stress generated in the layer of the CIS substrate 211 causes the bonded CIS substrate 211 and LOGIC substrate 212 to undergo deformation accompanied by warping, and the CIS substrate 211 and LOGIC substrate 212 both generate strains in opposite directions.

[0114] Then, as shown in Figure 35, the CIS substrate 211 is attached to the substrate holder 223, which serves as a thinning fixture, forcibly planarizing the CIS substrate 211 and the LOGIC substrate 212. This causes the bonded CIS substrate 211 and LOGIC substrate 212 to respectively distribute strain according to rigidity. Furthermore, as shown in Figure 36, when the substrate holder 223 is released from holding the intermediate laminate 230 formed by the thinned LOGIC substrate 212, the strain of the entire intermediate laminate 230 is biased towards the layer of the LOGIC substrate 212, whose rigidity has decreased due to thinning, while the strain of the CIS substrate 211 decreases.

[0115] Figure 37, as shown in Figure 33, is a schematic top view showing the distribution of nonlinear strain while the bonded CIS substrate 211 and LOGIC substrate 212 are held in the substrate holder 221. Furthermore, Figure 38 is a schematic top view showing the distribution of nonlinear strain in the intermediate laminate 230 shown in Figure 36. Comparing Figures 37 and 38, it is clear that the strain generated in the CIS substrate 211 by the first bonding is almost entirely transferred to the LOGIC substrate 212 in the intermediate laminate 230.

[0116] Figures 39 to 43 show the nonlinear strain of each layer of the CIS substrate 211 and LOGIC substrate 212, and the DRAM substrate 213, generated in the intermediate multilayer 230 during the second bonding process when performing the procedure of Embodiment 2 shown in the table of Figure 11. As shown in Figure 11, Embodiment 2 first releases the holding of the intermediate multilayer 230 during the second bonding process.

[0117] As shown in Figure 39, when the intermediate laminate 230 is released and bonding begins, the adsorption surface of the DRAM substrate 213 is adsorbed onto the substrate holder 221 and fixed in a flat state. The DRAM substrate 213 of Embodiment 2 is a third substrate.

[0118] Therefore, as shown in Figure 40, during the bonding stage of the intermediate laminate 230 and the DRAM substrate 213, the strain generated by the bonding occurs in each layer of the intermediate laminate 230. Furthermore, as shown in Figure 41, when the substrate holder 221 is released, the stress of the intermediate laminate 230 generates the opposite stress on the bonded DRAM substrate 213, and the whole substrate undergoes deformation accompanied by warping.

[0119] Then, as shown in Figure 42, when the DRAM substrate 213 is attached to the substrate holder 223, which serves as a thinning jig, and the intermediate stack 230 is forcibly planarized, the bonded intermediate stack 230 and DRAM substrate 213 are subjected to strain according to rigidity. Furthermore, as shown in Figure 43, when the completed stack 240 formed by thinning the CIS substrate 211 is released from the holding of the substrate holder 223, the strain distribution on the LOGIC substrate 212 and CIS substrate 211 increases, while the strain on the DRAM substrate 213 decreases.

[0120] Figure 44, as shown in Figure 40, is a schematic top view showing the distribution of nonlinear strain in the state where the intermediate laminate 230 and the DRAM substrate 213 are held in the substrate holder 221. Furthermore, Figure 45 is a schematic top view showing the distribution of nonlinear strain in the completed laminate 240 shown in Figure 43.

[0121] Comparing Figures 44 and 45, it is understood that the strain generated by the second bonding cancels out the strain in the layer of the LOGIC substrate 212 retained in the intermediate laminate 230, and the strain is generated only in the layer of the CIS substrate 211. Therefore, even in the final completed laminate 240, the strain is still retained only in the layer of the CIS substrate 211.

[0122] Figures 46 to 49 show the scaling strain generated during the bonding process in Embodiment 2. Figures 28 to 31 show arrows with hollow arrowheads. When the arrows at both ends of a straight line point outwards, it indicates that the spacing between structures on the substrate has increased, resulting in a scaling strain with increased scaling. Conversely, when a pair of arrows with opposing arrows are shown, it indicates that the spacing between structures on the substrate has narrowed, resulting in a scaling strain with decreased scaling of the substrate.

[0123] When the CIS substrate 211, which is held in the substrate holder 221, is bonded to the LOGIC substrate 212 and released from its holding, as shown by the arrow in Figure 46, a scaling factor strain is generated in the CIS substrate 211 during the bonding process, increasing the scaling factor of the CIS substrate 211. Continuing, as the LOGIC substrate 212 is thinned, as shown in Figure 47, the scaling factor strain generated in the CIS substrate 211 is transferred to the thinned LOGIC substrate 212 as a scaling factor strain that reduces the scaling factor. This eliminates the scaling factor strain in the CIS substrate 211.

[0124] Secondly, when the intermediate laminate 230 is released from the DRAM substrate 213 held in the substrate holder 221 for bonding, bonding process scaling strain is generated in the intermediate laminate 230, which increases its scaling factor. However, the LOGIC substrate 212 of the intermediate laminate 230 contains scaling strain that decreases its scaling factor during the initial bonding process when it is transferred from the CIS substrate 211.

[0125] Therefore, as shown in Figure 48, the scaling strain of the LOGIC substrate 212 cancels out the scaling strain generated during the bonding process with the DRAM substrate 213. Thus, no positional deviation caused by scaling strain occurs between the DRAM substrate 213 and the LOGIC substrate 212 in a fixed state where no scaling strain occurs.

[0126] Furthermore, the newly generated bonding process strain remains on the CIS substrate 211 even after the scaling strain has been eliminated. Continuing, when the CIS substrate 211 is thinned, as shown by the arrow symbol in Figure 49, although the scaling strain of the CIS substrate 211 is still retained, no positional deviation occurs between the CIS substrate 211 and the LOGIC substrate 212.

[0127] Figures 50 to 54 show the nonlinear strain of each layer of the CIS substrate 211 and LOGIC substrate 212 and the DRAM substrate 213 generated in the intermediate laminate 230 during the second bonding process when the procedure shown in the table of Figure 11 is performed. As shown in Figure 11, in Comparative Example 1, the holding of the intermediate laminate 230 is released during the second bonding.

[0128] Furthermore, the first bonding process in Comparative Example 1 is performed in the same manner as in Example 1. That is, in Comparative Example 1, the LOGIC substrate 212 is the first substrate, the CIS substrate 211 is the second substrate, and the DRAM substrate 213 is the third substrate. Therefore, the strain state in the intermediate laminate 230 formed by the first bonding is the same as that shown in Figures 18 and 20. Thus, all the strain generated by the first bonding occurs in the LOGIC substrate 212.

[0129] As shown in Figure 50, when the intermediate stack 230 is released and bonding begins, the adsorption surface of the DRAM substrate 213 is adsorbed onto the substrate holder 221 and fixed in a flat state. Therefore, as shown in Figure 51, during the bonding stage of the intermediate stack 230 and the DRAM substrate 213, the strain generated by bonding is generated in each layer of the intermediate stack 230. As a result, as shown in Figure 12, in Comparative Example 1, during the bonding stage of the intermediate stack 230 to the fixed DRAM substrate 213, the strain generated in the LOGIC substrate 212 layer of the intermediate stack 230 is doubled due to the superposition of the strain generated in the LOGIC substrate 212 layer by the first bonding and the strain generated in the entire intermediate stack 230 by the second bonding.

[0130] As shown in Figure 52, strain is also distributed on the DRAM substrate 213 when the substrate holder 221 is released. As shown in Figure 53, after being forcibly planarized by the substrate holder 223, which acts as a thinning jig, the CIS substrate 211 is thinned as shown in Figure 54. When the completed laminate 240 is released from the substrate holder 223, it returns to a state of doubled strain on the layers of the LOGIC substrate 212. Therefore, if an error is identified in the second bonding process when the substrate that was released from holding is found to be faulty, a large amount of strain will remain on the completed laminate 240.

[0131] Figure 55 is a schematic top view showing the distribution of nonlinear strain in the stacked DRAM substrate 213 and the intermediate stack 230 after the intermediate stack 230 is released while the DRAM substrate 213 is fixed to the substrate holder 221. Figure 56 is a schematic top view showing the distribution of nonlinear strain in the completed stack 240 as shown in Figure 54. From Figures 55 and 56, it can be seen that when the second bonding is performed using the procedure of Comparative Example 1, strain cannot be reduced by offsetting the second bonding.

[0132] Figures 57 to 60 show the scaling strain generated during the bonding process of Comparative Example 1. In Figures 57 to 60, the arrow symbols with hollow arrowheads, when showing outward-pointing arrows at both ends of a straight line, indicate that the spacing between structures on the substrate has increased, resulting in a scaling strain with increased scaling. Conversely, when a pair of arrow symbols with opposing arrows are shown, it indicates that the spacing between structures on the substrate has narrowed, resulting in a scaling strain with decreased substrate scaling.

[0133] When the CIS substrate 211, which is held in the substrate holder 221, is bonded to the LOGIC substrate 212 which is no longer held, as shown by the arrow in Figure 57, the magnification strain during the bonding process is generated in the LOGIC substrate 212, and the magnification of the LOGIC substrate 212 increases. When the LOGIC substrate 212 is thinned, as shown in Figure 58, since the magnification strain generated in the LOGIC substrate 212 does not affect the CIS substrate 211, the magnification strain of the LOGIC substrate 212 is maintained.

[0134] Secondly, when the intermediate laminate 230 is released from the DRAM substrate 213 held in the substrate holder 221 for bonding, a bonding process strain with increased magnification is generated on the intermediate laminate 230. Here, the LOGIC substrate 212 in the intermediate laminate 230 already contains a magnification strain with increased magnification generated by the initial bonding. Therefore, the bonding process strain overlaps, and as shown in Figure 59, a deformation with increased magnification is generated on the LOGIC substrate 212 in the radial direction outward, resulting in a magnification strain larger than that of the CIS substrate 211.

[0135] As described above, due to the large magnification strain generated on the LOGIC substrate 212, a positional deviation caused by the magnification strain occurs between the LOGIC substrate 212 and the DRAM substrate 213 in the completed laminate 240. The magnification strain generated on the CIS substrate 211 and the LOGIC substrate 212, as shown in Figure 60, remains even after the CIS substrate 211 is thinned, and the positional deviation between the CIS substrate 211 and the LOGIC substrate 212 cannot be eliminated.

[0136] Figures 61 to 65 show the nonlinear strain of each layer of the CIS substrate 211 and LOGIC substrate 212, and the DRAM substrate 213, generated in the intermediate laminate 230 during the second bonding process when the procedure of Comparative Example 2 shown in the table of Figure 11 is executed. As shown in Figure 11, Comparative Example 2 releases the holding of the DRAM substrate 213 during the second bonding. That is, in Comparative Example 2, the CIS substrate 211 is the first substrate, the LOGIC substrate 212 is the second substrate, and the DRAM substrate 213 is the third substrate.

[0137] As shown in Figure 61, when the DRAM substrate 213 is released from its holding position and bonding begins, the adsorption surface of the intermediate stack 230 is adsorbed onto the flat substrate holder 221 and fixed in a flat state. As shown in Figure 62, during the bonding stage of the intermediate stack 230 and the DRAM substrate 213, strain in the opposite direction to the strain generated on the LOGIC substrate 212 of the intermediate stack 230 is generated on the DRAM substrate 213. This increases the positional deviation due to the difference between the strain generated on the LOGIC substrate 212 and the strain generated on the DRAM substrate 213. Furthermore, as shown in Figure 63, when the substrate holder 221 is released from its holding position, the strain generated on the DRAM substrate 213 in the opposite direction to that of the CIS substrate 211 causes warping deformation throughout the bonded intermediate stack 230 and the DRAM substrate 213.

[0138] As shown in Figure 64, when the intermediate laminate 230 and the DRAM substrate 213 are held in place by the substrate holder 223, which acts as a thinning jig, and forced to planarize, the intermediate laminate 230 and the DRAM substrate 213 are rigidly distributed with strain. However, as shown in Figure 65, when the completed laminate 240 formed by thinning the CIS substrate 211 is released from the substrate holder 223, the strain of the entire completed laminate 240 overlaps on the LOGIC substrate 212 and the DRAM substrate 213. Therefore, the strain of each layer of the completed laminate 240 also increases.

[0139] Figure 66, as shown in Figure 62, is a schematic top view showing the strain distribution with the intermediate laminate 230 and DRAM substrate 213 held in the substrate holder 221. Furthermore, Figure 67 is a schematic top view showing the strain distribution in the completed laminate 240 shown in Figure 65.

[0140] Comparing Figures 66 and 67, it is understood that the strain generated by the second bonding initially occurs on the DRAM substrate 213. However, in the final completed laminate 240, the strain of the LOGIC substrate 212 is doubled due to the thinning of the CIS substrate 211, and strain is also generated on the CIS substrate 211.

[0141] Figures 68 to 71 show the magnification strain generated during the bonding process of Comparative Example 2. In Figures 68 to 71, the arrow symbols with hollow arrowheads, when showing outward-pointing arrows at both ends of a straight line, indicate that the spacing between the structures on the substrate has increased, resulting in a magnification strain that increases the magnification. Conversely, when a pair of arrow symbols with opposing arrows are shown, it indicates that the spacing between the structures on the substrate has narrowed, resulting in a magnification strain that decreases the magnification of the substrate.

[0142] When the CIS substrate 211, which is held in the substrate holder 221, is released from its holding position on the LOGIC substrate 212, as shown by the arrow in Figure 68, the scaling factor strain generated during the bonding process occurs in the CIS substrate 211, and the scaling factor strain of the CIS substrate 211 increases. Continuing, as the LOGIC substrate 212 is thinned, as shown in Figure 69, the scaling factor strain generated in the CIS substrate 211 is transferred to the thinned LOGIC substrate 212 as a scaling factor strain that reduces the scaling factor. This eliminates the scaling factor strain of the CIS substrate 211.

[0143] Secondly, when the intermediate laminate 230 having the aforementioned CIS substrate 211 and LOGIC substrate 212 is held in the substrate holder 221, and the DRAM substrate 213 is released from its holding to bond, a bonding process scaling strain occurs on the DRAM substrate 213, increasing the scaling factor. Additionally, the LOGIC substrate 212, which is in direct contact with the DRAM substrate 213, experiences a scaling strain that decreases the scaling factor, as described above. Therefore, as shown in Figure 70, a positional deviation occurs between the LOGIC substrate 212 and the DRAM substrate 213 due to the difference in scaling strain.

[0144] Continuing, during the thinning of the CIS substrate 211, the scaling strain generated on the DRAM substrate 213 is distributed to the thinned CIS substrate 211 and the LOGIC substrate 212. Therefore, as shown in Figure 71, the scaling strain generated during the secondary bonding process on the LOGIC substrate 212 is greater in the opposite direction to the scaling strain generated on the DRAM substrate 213, i.e., along the radial direction towards the center. Furthermore, once the scaling strain is eliminated, a scaling strain also occurs on the CIS substrate 211 along the radial direction towards the center.

[0145] As described above, in the second bonding process when the completed laminate 240 is manufactured, by first releasing the holding of the intermediate laminate 230 or the DRAM substrate 213 identified according to the procedure shown in Figure 10, a completed laminate 240 with reduced strain on the layers of the LOGIC substrate 212 and the DRAM substrate 213 can be formed. Furthermore, although the strain on the layers of the CIS substrate 211 is retained, the strain on the layers of the CIS substrate 211 can also be reduced by the method described below.

[0146] The first method involves, in the second bonding process of the methods described in Embodiments 1 and 2 above, bonding a DRAM substrate 213, which forms a structure, to a crystal orientation parallel to the bonding surface on the bonding surface of the CIS substrate 211, which is not thinned in the intermediate multilayer 230, at an angle of, for example, 45°. This cancels out the strain caused by the rigid distribution of the intermediate multilayer 230 and the DRAM substrate 213, reduces the strain generated by the second bonding, and ultimately reduces the strain retained on the CIS substrate 211.

[0147] Here, the angular deviation of the surface orientation refers to, for example, setting the state where the crystal orientation of the intermediate laminate 230 is consistent with the crystal orientation of the DRAM substrate 213 to 0°, maintaining the state where the center of the intermediate laminate 230 is consistent with the center of the DRAM substrate 213, and rotating the DRAM substrate 213 around the central axis of the intermediate laminate 230, and expressing it as an angle. Furthermore, the crystal orientation of each substrate can be known from the grooves, orientation planes, datasheets, etc. of the substrate 210. Moreover, by observing the position of the grooves, etc., relative to the center of the bonding surface of the substrate 210 or the intermediate laminate 230, the crystal orientation of the substrate 210 or the intermediate laminate 230 during bonding can be known. The rotation angle is not limited to 45°; as long as it is in the range of 22.5° to 67.5°, compared with aligning the crystal orientation, the strain generated by the second bonding can be reduced. By bonding the DRAM substrate 213 thus manufactured with the intermediate stack 230, the strain caused by the rigid distribution due to the anisotropy of the crystal orientation can be offset, and the strain generated by the bonding can be suppressed.

[0148] Furthermore, a second method to reduce the strain retained on the CIS substrate 211 can also be to further bond other substrates as support substrates to the DRAM substrate 213 after bonding the DRAM substrate 213 in the second bonding, and then thin the CIS substrate 211. In this way, by suppressing the strain generated in the DRAM substrate 213 in the second bonding to migrate to the CIS substrate 211 by the support substrate, the strain distributed to the CIS substrate 211 can be reduced.

[0149] Furthermore, in the third method, after bonding the DRAM substrate 213 in the second bonding, the DRAM substrate 213 is thinned before the CIS substrate 211 is thinned, and other support substrates are further bonded on the thinned DRAM substrate 213 before the CIS substrate 211 is thinned. In this way, most of the strain is transferred to the DRAM substrate 213, which can reduce the strain on the CIS substrate 211.

[0150] Furthermore, in the second and third methods described above, a support substrate that is not prone to strain should be used. Specifically, the second method may also use a crystal orientation on the bonding surface of the DRAM substrate 213, where the bonding surface has, for example, a crystal orientation rotated by 45°, and the third method may also use a crystal orientation on the bonding surface of the CIS substrate 211, where the bonding surface has, for example, a crystal orientation rotated by 45°. In addition, a circuit substrate that forms another layer of the laminate, such as a substrate with circuitry for performing processing connected to the DRAM substrate 213, may also be used as the support substrate. Furthermore, a multilayer is formed by bonding CIS substrate 211 and LOGIC substrate 212 together, where one of the CIS substrate 211 and LOGIC substrate 212 is tilted at, for example, 45° to the other substrate using the aforementioned crystal orientation. A multilayer is also formed by bonding DRAM substrate 213 and support substrate together, where one of the DRAM substrate 213 and support substrate is tilted at, for example, 45° to the other substrate using the aforementioned crystal orientation. The multilayer is then bonded to LOGIC substrate 212 and DRAM substrate 213 facing each other.

[0151] Furthermore, this embodiment illustrates an example where structures are formed on the two substrates joined in the first bonding process. However, it is also possible to use a substrate without structures, such as a bare silicon wafer, where one of the two substrates joined in the first bonding process is not released during bonding. In this case, even if a positional deviation occurs between the other substrate and the first substrate due to strain generated during the bonding process, it will not be a problem. Therefore, it is not necessary to pre-deform the first substrate to correspond to the strain generated in the other substrate. In this case, the bonding conditions in the first bonding process can be determined based on information in the second bonding process regarding the strain estimated to be generated in the third substrate, where the strain generated in the first bonding process and the strain generated on the third substrate containing the intermediate laminate are of the same shape. Similarly, the bonding conditions in the second bonding process can be determined based on information in the first bonding process regarding the strain generated in the first substrate.

[0152] Furthermore, this embodiment shows an example of sequentially stacking a CIS substrate 211, a LOGIC substrate 212, and a DRAM substrate 213. However, it is also possible to stack the CIS substrate 211, DRAM substrate 213, and LOGIC substrate 212 in that order instead. Additionally, at least two of the three or more substrates stacked may be of the same type. In this case, for example, two DRAM substrates may be bonded together to form an intermediate stack, and then a LOGIC substrate may be stacked on this intermediate stack. In this case, of the two DRAM substrates, the one released during bonding is the first substrate, and the other is the second substrate, and either DRAM substrate is thinned.

[0153] The above description uses embodiments to illustrate the present invention; however, the technical scope of the present invention is not limited to the scope described in the above embodiments. Those skilled in the art will understand that the above embodiments can be modified or improved in various ways. As will be clear from the claims, such modifications or improvements are still included within the technical scope of the present invention.

[0154] It should be noted that the execution order of actions, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, specification, and drawings can be arbitrary unless specifically stated as "before" or "beforehand," or unless the output of a previous process is used in a later process. Regarding the action flow in the claims, specification, and drawings, even if terms such as "firstly" or "secondly" are used expediently, it does not imply that the actions must be performed in that specific order.

[0155] 100: Substrate stacking device 110: Frame 120, 130: Baseboard box 140:Transportation Department 150: Control Department 210:Substrate 211:CIS substrate 212:LOGIC substrate 213:DRAM substrate 217: Substrate cutting line 218: Mark 219: Circuit Area 221:Substrate holder 222:Substrate holder 223:Substrate holder 230: Intermediate laminate 240: Complete the laminated body 300: Joint 310: Frame 311: Top Plate 313: Base Plate 321: Fixed platform 322: Microscope 323: Activation device 331: X-direction drive unit 332: Y-direction drive unit 333: Z-direction drive unit 341: Mobile platform 342: Microscope 343: Activation device 400: Holder Storage Cabinet 500: Pre-aligner

Claims

1. A bonding method comprising: a first bonding stage in which a first substrate is released from holding a second substrate to bond the first substrate and the second substrate to form a first laminate; a holding stage in which the first laminate is held on the side of the second substrate after the second substrate of the first laminate is released; a stage of thinning the first substrate after the holding stage; and a second bonding stage in which a second laminate is formed by bonding the first substrate and the third substrate thinned in the thinning stage; and releasing the third substrate from holding in the second bonding stage.

2. The bonding method as described in claim 1, wherein in the first bonding stage, after the protruding area of ​​the first substrate comes into contact with a portion of the second substrate, the first substrate and the second substrate are bonded by releasing the holding of the first substrate; and in the second bonding stage, after the protruding area of ​​the third substrate comes into contact with a portion of the first substrate, the first substrate and the third substrate are bonded by releasing the holding of the third substrate.

3. A bonding method comprising: a first bonding stage in which a first substrate is released from holding a second substrate, and the first substrate and the second substrate are bonded to form a first laminate; a holding stage in which the first laminate is held on the side of the first substrate after the second substrate of the first laminate is released; a stage of thinning the second substrate after the holding stage; and a second bonding stage in which a second laminate is formed by bonding the second substrate and the third substrate thinned in the thinning stage; and releasing the first laminate from holding in the second bonding stage.

4. The bonding method as described in claim 3, wherein in the first bonding stage, after the protruding area of ​​the first substrate comes into contact with a portion of the second substrate, the first substrate and the second substrate are bonded by releasing the holding of the first substrate; and in the second bonding stage, after the protruding area of ​​the second substrate comes into contact with a portion of the third substrate, the second substrate and the third substrate are bonded by releasing the holding of the first laminate.

5. A bonding method comprising: a first bonding stage, wherein a first substrate and a second substrate are bonded to form a first laminate by releasing the holding of a first substrate while holding a second substrate; a holding stage, wherein the first laminate is held on one side of the first substrate and the second substrate after the holding of the second substrate of the first laminate is released; a stage after the holding stage for thinning the other of the first substrate and the second substrate that is not held; and a second bonding stage, wherein a second laminate is formed by bonding the other substrate thinned in the thinning stage to a third substrate; wherein when the first substrate is thinned in the thinning stage, the holding of the third substrate is released in the second bonding stage; and when the second substrate is thinned in the thinning stage, the holding of the first laminate is released in the second bonding stage.

6. The bonding method as described in any one of claims 1, 3, and 5, wherein the aforementioned first laminate comprises: a light-receiving element substrate having a plurality of light-receiving elements; and a processing substrate for processing signals generated by the aforementioned light-receiving element substrate.

7. The bonding method as described in claim 6, wherein the aforementioned third substrate is a memory substrate having a plurality of memory cells.

8. The bonding method as described in claim 7, wherein the crystal orientation of the surface on which the first substrate is bonded to the second substrate in the direction parallel to the surface is rotated at an angle of 22.5° to 67.5°.

9. The bonding method as described in claim 7, further comprising: a third bonding stage in which a support substrate is bonded on the memory substrate preceding the second laminate; and a thinning stage in which the light-receiving element substrate is thinned after the third bonding stage.

10. The bonding method as described in claim 7, further comprising: a memory thinning stage, which thins the memory substrate preceding the second laminate; a third bonding stage, which bonds a support substrate onto the memory substrate thinned in the memory thinning stage; and a thinning stage, which, after the third bonding stage, thins the light-receiving element substrate.

11. The bonding method as described in claim 9, wherein when bonding the aforementioned support substrate, after forming a third region where a portion of the aforementioned memory substrate and a portion of the aforementioned support substrate are bonded, the holding of the aforementioned support substrate is released, thereby expanding the aforementioned third region.

12. The bonding method as described in claim 10, wherein when bonding the aforementioned support substrate, after forming a third region where a portion of the aforementioned memory substrate and a portion of the aforementioned support substrate are bonded, the holding of the aforementioned support substrate is released, thereby expanding the aforementioned third region.

13. The bonding method as described in claim 7, further comprising: a memory thinning stage, which involves thinning the memory substrate preceding the aforementioned second laminate; and a third bonding stage, which involves bonding a support substrate onto the thinned memory substrate after the aforementioned memory thinning stage; on the bonding surface of the thinned memory substrate and the aforementioned support substrate, the directions of the crystal orientations parallel to that surface of the aforementioned memory substrate and the aforementioned support substrate are rotated by 45° relative to each other.

14. The bonding method as described in claim 13, wherein the aforementioned support substrate has circuitry connected to the aforementioned memory substrate.

15. The bonding method as described in any one of claims 1, 3, and 5, wherein after forming a first bonding region by bonding a portion of the first substrate and a portion of the second substrate in the first bonding stage, the first bonding region is expanded by releasing the holding of the first substrate to form the first laminate; and after forming a second bonding region by bonding a portion of the substrate thinned in the thinning stage to a portion of the third substrate in the second bonding stage, the second bonding region is expanded by releasing the holding of either the first laminate or the third substrate to form the second laminate.

16. A bonding apparatus comprising: a first holding portion for holding a laminate of the first substrate and the second substrate bonded by releasing the holding of the first substrate while holding the second substrate, after the holding of the second substrate is released; a second holding portion for holding the laminate formed by thinning the first substrate; and a third holding portion for holding a third substrate bonded to the thinned first substrate of the laminate; wherein when the thinned first substrate of the laminate is bonded to the third substrate, the holding of the third substrate caused by the third holding portion is released.

17. The bonding device as claimed in claim 16, wherein after the protruding region of the first substrate comes into contact with a portion of the second substrate, the first substrate and the second substrate are bonded by releasing the holding of the first substrate; and after the protruding region of the third substrate comes into contact with a portion of the first substrate, the first substrate and the third substrate are bonded by releasing the holding of the third substrate.

18. A bonding apparatus comprising: a first holding portion for holding a laminate of the first substrate and the second substrate bonded by releasing the holding of the first substrate while holding the second substrate, after the holding of the second substrate is released; a second holding portion for holding the laminate formed by thinning the second substrate; and a third holding portion for holding a third substrate bonded to the thinned second substrate of the laminate; wherein when the thinned second substrate of the laminate is bonded to the third substrate, the holding of the laminate caused by the second holding portion is released.

19. The bonding device as claimed in claim 18, wherein after the protruding region of the first substrate comes into contact with a portion of the second substrate, the first substrate and the second substrate are bonded by releasing the holding of the first substrate; and after the protruding region of the second substrate comes into contact with a portion of the third substrate, the second substrate and the third substrate are bonded by releasing the holding of the first laminate.

20. A bonding apparatus comprising: a holding unit that holds the first laminate, which is bonded by releasing the holding of the first substrate and the second substrate while holding the second substrate, on one side of the first substrate and the second substrate after the holding of the second substrate is released; an obtaining unit that obtains information identifying which of the first substrate and the second substrate has been thinned when the other of the first substrate and the second substrate is thinned to form a second laminate by bonding a third substrate to the first laminate; an identification unit that identifies the third substrate when the first substrate is thinned and the first laminate when the second substrate is thinned, based on the information obtained by the obtaining unit; and a bonding unit that releases the holding of the first laminate or the third substrate identified by the identification unit and laminates the thinned one of the first substrate and the second substrate with the third substrate.

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