Coating unit and substrate bonding device equipped with same

Abstract

This coating unit includes: a chuck that rotates about an axis that is orthogonal to a main surface of a bonded substrate, which is composed of two substrates bonded to each other, and passes through the center of the main surface, while holding the bonded substrate; and a filling liquid nozzle that ejects a plurality of droplets of a filling liquid, which changes into a solid or semi-solid filler, toward the bonded substrate that is held by the chuck, thereby supplying the filling liquid to an annular groove that is formed between the outer peripheral parts of the two substrates bonded to each other.

Description

Coating unit and substrate bonding device equipped with same

[0001] The present invention relates to a coating unit for coating two bonded substrates with a filler liquid, and a substrate bonding apparatus including the same. The substrates include, for example, semiconductor wafers, substrates for FPDs (Flat Panel Displays) such as liquid crystal displays and organic electroluminescence (EL) displays, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, and substrates for solar cells.

[0002] Patent Document 1 discloses an edge state checking device capable of determining the presence or absence of internal defects in a protective member formed on the outer peripheral edge of a substrate. Paragraph 0087 of Patent Document 1 states, "As shown in Figures 10 and 11 , an edge state checking device 1 according to a second embodiment includes, in addition to the configuration of the edge state checking device 1 according to the first embodiment, a protective member forming unit LN for forming a protective member w4 on the outer peripheral edge of the bonded substrate W. The protective member forming unit LN is connected to a supply system (not shown) that supplies a coating liquid for the protective member, and includes a nozzle member capable of ejecting the coating liquid supplied from the supply system."

[0003] JP 2023-43003 A

[0004] Patent Document 1 only describes "a nozzle member capable of ejecting a coating liquid supplied from a supply system," and does not clarify in what form the coating liquid is ejected from the nozzle member.

[0005] At least one embodiment of the present invention provides a coating unit that can precisely control the amount of filler liquid supplied to two bonded substrates, and a substrate bonding apparatus including the same.

[0006] One embodiment of the present invention provides an application unit including: a chuck that holds a bonded substrate, which is two bonded substrates, and rotates about an axis that is perpendicular to the main surfaces of the bonded substrates and passes through the center of the main surfaces; and a filler liquid nozzle that sprays a plurality of droplets of a filler liquid that transforms into a solid or semi-solid filler toward the bonded substrates held by the chuck, thereby supplying the filler liquid to an annular groove formed between the outer peripheries of the two bonded substrates. The bonded substrates include two flat surfaces that are parallel to each other. The two flat surfaces of the bonded substrates are non-bonded surfaces of the two bonded substrates. The main surface of the bonded substrate may be either of the two flat surfaces of the bonded substrates.

[0007] In the above embodiment, at least one of the following features may be added to the application unit.

[0008] The filler liquid nozzle is an inkjet nozzle that sprays a plurality of droplets of the filler liquid in substantially the same direction toward the annular groove.

[0009] The application unit further includes a position detector that detects the position of the outer periphery of the bonded substrate held by the chuck, and a nozzle actuator that moves the filling liquid nozzle in accordance with the position of the outer periphery detected by the position detector.

[0010] The application unit further includes a control device that performs at least one of position control, which causes the nozzle actuator to move the filling liquid nozzle in accordance with the position of the outer periphery detected by the position detector while causing the position detector to detect the position of the outer periphery, and flow rate control, which changes the amount of filling liquid sprayed from the filling liquid nozzle per unit time in accordance with the position of the outer periphery detected by the position detector while causing the position detector to detect the position of the outer periphery.

[0011] The coating unit further includes a void detector that detects voids within the filling liquid or filling body in the annular groove and voids between the bonding surfaces of the two bonded substrates when the chuck holds the bonded substrates.

[0012] The filling liquid nozzle includes a large-diameter nozzle that sprays multiple droplets of the filling liquid from a spray port toward the bonded substrate held by the chuck, and a small-diameter nozzle that sprays multiple droplets of the filling liquid from a spray port having a smaller area than the spray port of the large-diameter nozzle toward the bonded substrate held by the chuck.

[0013] Another embodiment of the present invention provides a substrate bonding apparatus including: a bonding unit that bonds two substrates together; and an application unit that applies a filling liquid that changes into a solid or semi-solid filler to a bonded substrate, which is the two substrates bonded by the bonding unit; wherein the application unit includes a chuck that holds the bonded substrate and rotates about an axis that is perpendicular to the main surfaces of the bonded substrates and passes through the centers of the main surfaces; and a filling liquid nozzle that sprays a plurality of droplets of the filling liquid toward the bonded substrate held by the chuck, thereby supplying the filling liquid to an annular groove formed between the outer peripheries of the two bonded substrates.

[0014] In the above embodiment, at least one of the following features may be added to the substrate bonding apparatus.

[0015] The bonding unit includes a first chuck and a second chuck that respectively hold the two substrates before they are bonded, and a bonding actuator that moves the first chuck and the second chuck relative to each other to bring the two substrates held by the first chuck and the second chuck into contact with each other, and the coating unit further includes a chamber that houses the chucks, the filling liquid nozzle, the first chuck, and the second chuck.

[0016] The bonding unit further includes a void detector for detecting voids between the bonding surfaces of the two bonded substrates and voids within the filling liquid or filling body in the annular groove.

[0017] 1 is a schematic diagram showing an example of the appearance of two substrates before and after bonding; FIG. 2 is a schematic diagram showing an example of cross sections of two substrates before and after bonding; FIG. 3 is a schematic diagram showing an example of cross sections of two substrates before and after supplying a filler liquid to the outer peripheries of the two bonded substrates; FIG. 4 is a schematic diagram showing an example of cross sections of two bonded substrates before and after thinning the two bonded substrates; FIG. 5 is a process diagram for explaining a substrate bonding method according to an embodiment of the present invention; FIG. 6 is a schematic plan view of a substrate bonding apparatus according to an embodiment of the present invention; FIG. 7 is a schematic diagram showing the interior of a pre-activation aligner viewed horizontally; FIG. 8 is a schematic diagram showing the interior of a pre-activation aligner viewed from directly above; FIG. 9 is a schematic diagram showing the interior of an activation unit viewed horizontally; FIG. 10 is a schematic diagram showing the interior of an activation unit viewed from directly above; FIG. 11 is a schematic diagram showing the interior of a pre-bonding cleaning unit viewed horizontally; FIG. 12 is a schematic diagram showing the interior of a pre-bonding cleaning unit viewed from directly above; FIG. 13 is a schematic diagram showing the interior of a coating unit viewed horizontally; FIG. 14 is a schematic diagram of a filling liquid nozzle; FIG. 15 is a schematic diagram showing the interior of a bonding unit viewed horizontally; FIG. 16 is a schematic diagram showing the interior of a bonding unit viewed horizontally; FIG. 17 is a schematic diagram showing the interior of a grinding unit viewed horizontally. FIG. 1 is a schematic view of the inside of a grinding unit as seen from directly above. FIG. 2 is a block diagram showing the electrical configuration of a substrate bonding apparatus. FIG. 3 is a schematic cross-sectional view of the outer periphery of a substrate. FIG. 4 is a schematic cross-sectional view of the inside of a coating unit as seen from directly above. FIG. 5 is a schematic cross-sectional view showing a state in which a filler liquid is being supplied to an annular groove formed between the outer peripheries of two bonded substrates. FIG. 6 is a schematic cross-sectional view showing a state in which a void between two bonded substrates is being detected by a void detector. FIG. 7 is a schematic horizontal view of the inside of a coating unit according to another embodiment of the present invention. FIG. 8 is a schematic view showing a state in which bonded substrates, filler liquid, and voids in a filler are being photographed. FIG. 9 is a schematic plan view of a substrate showing a device region and a non-device region.

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] In the following description, a bonded substrate W refers to two bonded substrates W, a pre-bonded substrate W refers to one substrate W before bonding, and a bonded substrate W refers to one substrate W after bonding. Bonding is synonymous with bonding.

[0020] The first substrate W1 refers to a pre-bonded substrate W. The second substrate W2 refers to another pre-bonded substrate W. The bonded first substrate W1 and second substrate W2 refer to a bonded substrate W. Two bonded substrates W also refer to a bonded substrate W. When it does not matter whether it is a bonded substrate W, a pre-bonded substrate W, or a bonded substrate W, it is simply referred to as a substrate W.

[0021] Fig. 1A is a schematic diagram showing an example of the appearance of two substrates W before and after bonding. Fig. 1B is a schematic diagram showing an example of the cross section of two substrates W before and after bonding. Fig. 1C is a schematic diagram showing an example of the cross section of two bonded substrates W before and after supplying a fill liquid FL to the outer peripheries of the two bonded substrates W. Fig. 1D is a schematic diagram showing an example of the cross section of two bonded substrates W before and after thinning the two bonded substrates W.

[0022] As shown in FIG. 1A , the first substrate W1 and the second substrate W2 are flat, circular plates with the same diameter. The diameters of the first substrate W1 and the second substrate W2 may be 300 mm or other diameters. The thermal expansion coefficient of the first substrate W1 may be the same as or different from the thermal expansion coefficient of the second substrate W2. The first substrate W1 includes a circular substrate WD1, and the second substrate W2 includes a circular substrate WD2. The substrate WD1 and the substrate WD2 are made of a semiconductor such as single crystal silicon. The substrate WD1 and the substrate WD2 may also be made of a material other than a semiconductor.

[0023] Both the substrate WD1 and the substrate WD2 include a circular front surface and a back surface that are parallel to each other, and an annular end surface that connects the outer edges of the front surface and the back surface. The front surface and the back surface of the substrate WD1 are flat surfaces that are parallel to each other. The front surface and the back surface of the substrate WD2 are similar. The front surfaces of the substrate WD1 and the substrate WD2 are device formation surfaces on which devices such as transistors are formed. The back surfaces of the substrate WD1 and the substrate WD2 are non-device formation surfaces on which devices are not formed. Both the front surface and the back surface of the substrate WD1 or the substrate WD2 may be device formation surfaces.

[0024] The outer periphery of the substrate WD1 forms a V-shaped notch that opens at the end face of the substrate WD1 when the substrate WD1 is viewed in a direction perpendicular to the surface of the substrate WD1. The outer periphery of the substrate WD1 may form an orientation flat (so-called orientation flat) instead of a notch. The notch and orientation flat indicate the crystal orientation of the substrate WD1 or the substrate WD2. The first substrate W1 is positioned in the circumferential direction of the first substrate W1 based on the notch or orientation flat of the first substrate W1. The same applies to the second substrate W2.

[0025] As shown in FIG. 1B , the first substrate W1 includes a device layer WC1 covering the surface of the substrate WD1 and a bonding layer WB1 covering the surface of the device layer WC1. The second substrate W2 includes a device layer WC2 covering the surface of the substrate WD2 and a bonding layer WB2 covering the surface of the device layer WC2. Devices such as transistors are disposed in the device layers WC1 and WC2. The devices are covered by the bonding layers WB1 and WB2. The bonding layers WB1 and WB2 are transparent or semi-transparent insulating layers. The bonding layers WB1 and WB2 may be silicon oxide films or thin films made of a material other than silicon oxide. In the former case, the bonding layers WB1 and WB2 may be silicon oxide films made using TEOS (tetraethoxysilane).

[0026] The surface of the bonding layer WB1 of the first substrate W1 is the bonding surface WA1 of the first substrate W1. The surface of the bonding layer WB2 of the second substrate W2 is the bonding surface WA2 of the second substrate W2. The first substrate W1 and the second substrate W2 are bonded so that the bonding surface WA1 of the first substrate W1 faces the bonding surface WA2 of the second substrate W2. The surface of the first substrate W1 is the bonding surface WA1 that comes into contact with the atmosphere in the space in which the first substrate W1 is placed. The surface of the second substrate W2 is the bonding surface WA2 that comes into contact with the atmosphere in the space in which the second substrate W2 is placed.

[0027] 2 is a process diagram illustrating a substrate bonding method according to one embodiment of the present invention. When bonding a first substrate W1 and a second substrate W2, an activation step (step S1 in FIG. 2) is performed to activate the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2, followed by a cleaning step (step S2 in FIG. 2) to clean and dry the two activated substrates W. This is followed by an inversion step (step S3 in FIG. 2) to invert one of the first substrate W1 and the second substrate W2.

[0028] After one of the first substrate W1 and the second substrate W2 has been inverted, the following steps are performed: an alignment confirmation step (step S4 in FIG. 2 ) of confirming the alignment, which indicates the relative position and angle of the first substrate W1 and the second substrate W2; an alignment adjustment step (step S5 in FIG. 2 ) of adjusting the alignment of the first substrate W1 and the second substrate W2 based on the confirmed alignment; and a substrate contact step (step S6 in FIG. 2 ) of bonding the first substrate W1 and the second substrate W2 by bringing them into contact with each other after the alignment adjustment. This is followed by an inspection step (step S7 in FIG. 2 ) of inspecting the bonding accuracy of the first substrate W1 and the second substrate W2, i.e., the amount of misalignment between the two bonded substrates W and the amount of misalignment between the two bonded substrates W (the angle around the center of the substrate W).

[0029] The activation step may be a plasma treatment in which plasma such as oxygen plasma is applied to the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2. In this case, moisture in the air or moisture supplied to the substrate W during the cleaning step comes into contact with the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2 that have been irradiated with the plasma, forming hydrophilic groups such as hydroxyl groups (OH groups) on the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2. The plasma treatment is an example of surface modification that modifies the surface of the substrate W. The activation step may also be a wet treatment in which a hydrophilizing liquid that forms hydrophilic groups is supplied to the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2.

[0030] The substrate contacting step may be a step of directly bonding two substrates W in the atmosphere at room temperature (e.g., 20 to 30°C). The substrate contacting step may be a step of performing face-to-face bonding in which the two substrates W are bonded together so that their surfaces face each other. In this case, the surfaces of the two substrates W correspond to the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2. The substrate contacting step may be a step of bonding two substrates W together without pressing one of the two substrates W against the other of the two substrates W, or by pressing one of the two substrates W against the other of the two substrates W with a pressure that does not damage devices formed on the two substrates W.

[0031] 1B shows a cross section of the first substrate W1 and the second substrate W2 cut along a plane perpendicular to the first substrate W1 and the second substrate W2. The ratio of the thickness of the device layer WC1 and the device layer WC2 to the thickness of the bonding layer WB1 and the bonding layer WB2 shown in FIG. 1B is not necessarily the same as the actual ratio. FIG. 1B shows an example in which hydroxyl groups, which are an example of hydrophilic groups, are formed on the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2 before bonding. In this example, oxygen atoms (O) in the hydroxyl groups are bonded to silicon atoms (Si) in the bonding layers WB1 and WB2.

[0032] Before bonding, the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2 are terminated with multiple hydroxyl groups. When the bonding surface WA1 of the first substrate W1 and the bonding surface WA2 of the second substrate W2 are brought into contact, the first substrate W1 and the second substrate W2 are bonded together due to the intermolecular force acting between the two hydroxyl groups. In some cases, water molecules are released from the two hydroxyl groups, and silicon atoms in the bonding layer WB1 of the first substrate W1 and silicon atoms in the bonding layer WB2 of the second substrate W2 are bonded together via oxygen atoms. In this manner, the first substrate W1 and the second substrate W2 are bonded together.

[0033] As shown in FIG. 1C , after bonding the first substrate W1 and the second substrate W2, a coating process (step S8 in FIG. 2 ) is performed in which a filler liquid FL is applied to the annular groove WG formed between the outer peripheries of the bonded first substrate W1 and the second substrate W2. Then, as shown in FIG. 1D , a grinding process (step S9 in FIG. 2 ) is performed in which one of the bonded first substrate W1 and the second substrate W2 is ground to thin the bonded first substrate W1 and the second substrate W2, i.e., the bonded substrate W. Then, a cleaning process (step S10 in FIG. 2 ) is performed in which the thinned bonded substrate W is cleaned and dried. FIG. 1D illustrates an example in which the thickness of the bonded substrate W is reduced by grinding the first substrate W1. Instead of reducing the thickness of the first substrate W1, the thickness of the second substrate W2 may also be reduced.

[0034] The inspection process (step S7 in FIG. 2) may be performed after the coating process (step S8 in FIG. 2) rather than before. In this case, the inspection process may be performed before the grinding process (step S9 in FIG. 2) or after the grinding process. The inspection process may be performed before and after the grinding process. In this case, the bonding accuracy before and after the grinding process may be compared. A pass / fail judgment may be made based on whether the amount of change in bonding accuracy exceeds a threshold value. A pass rate may be calculated based on the pass / fail judgment, or a pass map may be created that shows the relationship between substrates W that have been passed or failed and substrates W that have passed, and at least one of the pass rate and the pass map may be recorded or displayed.

[0035] As shown in Figures 1C and 1D, the filler liquid FL is a liquid that changes into a solid or semi-solid filler FS. The filler liquid FL may be a solution in which the filler FS (corresponding to the solute) is dissolved in a solvent, or a liquid of the filler FS (a liquid in which the concentration of the filler FS is 100% or nearly 100%), or it may be any other liquid. When the filler liquid FL is a solution containing the filler FS and a solvent, the solvent may be a liquid of a substance more volatile than water, such as IPA (isopropyl alcohol). For example, the filler liquid FL may be a spin-on-glass (SOG) liquid containing a siloxane component (corresponding to the solute) and an alcohol (corresponding to the solvent).

[0036] When the grinding process is initiated, the filler liquid FL in the annular groove WG has been transformed into the filler FS. If necessary, a process for initiating or accelerating the transformation of the filler liquid FL into the filler FS may be performed before the grinding process. For example, when the filler liquid FL transforms into the filler FS by evaporation, a portion of the filler liquid FL may be evaporated by heating the filler liquid FL and / or reducing the air pressure. When the filler liquid FL transforms into the filler FS by hardening, the filler liquid FL may be hardened by heating the filler liquid FL and / or irradiating the filler liquid FL with light. These processes may be performed while the filler liquid FL is being supplied, after the supply of the filler liquid FL has been stopped, or both.

[0037] Next, the substrate bonding apparatus 1 that bonds two substrates W as described above will be described.

[0038] 3 is a schematic plan view of a substrate bonding apparatus 1 according to one embodiment of the present invention. In the following description, the up-down direction, left-right direction, and front-rear direction refer to the up-down direction, left-right direction, and front-rear direction of the substrate bonding apparatus 1 unless otherwise specified. The up-down direction is the vertical direction. The left-right direction and the front-rear direction are two horizontal directions that are perpendicular to each other. The left-right direction is the arrangement direction of multiple carriers CA held on multiple load ports LP. Each carrier CA is held on the load port LP with the opening of the carrier CA facing rearward.

[0039] The substrate bonding apparatus 1 is an apparatus for bonding two disk-shaped substrates W. The substrate bonding apparatus 1 includes a plurality of load ports LP on each of which a plurality of carriers CA, such as FOUPs (Front-Opening Unified Pods), are placed, each carrier CA accommodating a plurality of substrates W, a plurality of processing units 2 for processing the substrates W transferred from the plurality of load ports LP, a transport system TS for transporting the substrates W between the plurality of load ports LP and the plurality of processing units 2, and an outer wall 1a forming an enclosed space accommodating the plurality of processing units 2 and the transport system TS. The substrate bonding apparatus 1 further includes a control device 3 for controlling the substrate bonding apparatus 1.

[0040] 3 shows an example in which three load ports LP are provided. The three load ports LP include a first load port LP1 on which a carrier CA accommodating a first substrate W1 is placed, a second load port LP2 on which a carrier CA accommodating a second substrate W2 is placed, and a third load port LP3 on which a carrier CA accommodating the bonded first and second substrates W1 and W2 is placed. The first load port LP1 and the second load port LP2 are load ports on which carriers CA accommodating substrates W to be bonded in the substrate bonding apparatus 1 are placed. The third load port LP3 is an unload port on which a carrier CA accommodating two substrates W bonded in the substrate bonding apparatus 1 is placed.

[0041] The multiple processing units 2 include a pre-activation aligner 10, an activation unit 20, a pre-bonding cleaning unit 30, a pre-bonding aligner, a coating unit 40, a bonding unit 50, a grinding unit 60, and a post-grinding cleaning unit 70. Fig. 3 shows an example in which two pre-activation aligners 10, two activation units 20, two pre-bonding cleaning units 30, two pre-bonding aligners, and two coating units 40 are provided, and the pre-bonding aligner is integrated with the coating unit 40.

[0042] The pre-activation aligner 10 is a unit that positions the substrate W in the circumferential direction of the substrate W based on the notch or orientation flat. The same is true for the pre-bonding aligner. The activation unit 20 is a unit that performs plasma treatment to activate the front or back surface of the substrate W by bringing plasma into contact with the front or back surface of the substrate W. The pre-bonding cleaning unit 30 is a unit that cleans the substrate W by supplying a cleaning liquid to the substrate W.

[0043] The bonding unit 50 is a unit that bonds two substrates W by bringing them into contact with each other. The coating unit 40 is a unit that supplies a filler liquid to an annular groove WG (see FIG. 1C ) formed between the outer peripheries of the two bonded substrates W. The grinding unit 60 is a unit that thins the two bonded substrates W by grinding the two bonded substrates W. The post-grinding cleaning unit 70 is a unit that cleans the two substrates W by supplying a cleaning liquid to the two substrates W that have been thinned by grinding.

[0044] The transport system TS transports substrates W from the first load port LP1 and the second load port LP2 to the plurality of processing units 2, and transports substrates W from the plurality of processing units 2 to the third load port LP3. The transport system TS further transports substrates W between the plurality of processing units 2. The transport system TS may include at least one transport robot TR that transports one or more substrates W in a horizontal position on a transport path TP indicated by a thick line in Figure 3.

[0045] The transport robot TR includes at least one hand TH that holds one substrate W in a horizontal position. The transport robot TR moves along the transport path TP while holding the substrate W horizontally with the hand TH. Figure 3 shows an example in which the transport path TP extends from each of the first load port LP1 and the second load port LP2 to a plurality of processing units 2, and returns from the plurality of processing units 2 to the third load port LP3.

[0046] The following describes the processing units 2. First, the pre-activation aligner 10 will be described.

[0047] 4A is a schematic diagram showing the interior of the aligner 10 as seen horizontally before activation, and FIG. 4B is a schematic diagram showing the interior of the aligner 10 as seen from directly above before activation.

[0048] 4A and 4B, the pre-activation aligner 10 includes a chamber 11 that forms an internal space in which the substrate W is placed and a passage opening through which the substrate W passes to enter and exit the internal space, and a chuck 14 that holds the substrate W horizontally within the chamber 11. The chamber 11 includes a partition wall 12 that forms the internal space and the passage opening, and a door 13 that moves relative to the partition wall 12 to open and close the passage opening.

[0049] The pre-activation aligner 10 further includes an electric motor 15 that rotates the chuck 14 to rotate the substrate W around a vertical center of rotation A1 that passes through the center of the substrate W held on the chuck 14, an outer periphery position sensor 16 that identifies the orientation of the notch or orientation flat by detecting the contour shape of the substrate W, and a control device 3 that causes the electric motor 15 to rotate the chuck 14 based on the detection value of the outer periphery position sensor 16, thereby stopping the substrate W at a position where the orientation of the notch or orientation flat coincides with a reference direction.

[0050] The chuck 14 may be a mechanical chuck that holds the substrate W horizontally by pressing multiple chuck pins horizontally against the edge surface of the substrate W, or a vacuum chuck that holds the substrate W horizontally by attracting the lower surface of the substrate W to the upper surface of a spin base arranged below the substrate W. Figures 4A and 4B show an example of the latter. In the latter case, the outer periphery position sensor 16 may identify the position of the center of the substrate W by detecting the contour shape of the substrate W. In this case, the pre-activation aligner 10 may further include a centering actuator that moves the chuck 14 horizontally to bring the center of the substrate W closer to the center of rotation A1 of the substrate W.

[0051] An actuator is a device that converts driving energy, such as electrical, fluid, magnetic, thermal, or chemical energy, into mechanical work, i.e., the movement of a tangible object. Actuators include electric motors (rotary motors), linear motors, air cylinders, and other devices. When the movement of the actuator differs from the movement of the object, a motion converter may be provided to convert the movement of the actuator into linear or rotational motion. For example, if the actuator is an electric motor that moves the object linearly, the rotation of the electric motor may be converted into linear motion by a motion converter such as a ball screw and ball nut.

[0052] Next, the activation unit 20 will be described.

[0053] Fig. 5A is a schematic diagram showing the inside of the activation unit 20 as seen horizontally. Fig. 5B is a schematic diagram showing the inside of the activation unit 20 as seen from directly above.

[0054] 5A and 5B , the activation unit 20 includes a chamber 21 that defines an internal space in which the substrate W is placed and a passage through which the substrate W passes to enter and exit the internal space, a lower electrode 24L that horizontally supports the substrate W within the chamber 21, an upper electrode 24u that is positioned above the substrate W held by the lower electrode 24L, a gas pipe 25p that supplies a processing gas between the upper electrode 24u and the lower electrode 24L, a gas valve 25v that opens and closes the gas pipe 25p, a power supply 26 that converts the processing gas between the upper electrode 24u and the lower electrode 24L into plasma, and a vacuum pump 27 that exhausts gas from the internal space. The chamber 21 includes a partition wall 22 that defines the internal space and the passage, and a door 23 that moves relative to the partition wall 22 to open and close the passage.

[0055] Although not shown, the gas valve 25v includes a valve body provided with an annular valve seat through which gas passes, a valve element movable relative to the valve seat, and an actuator that moves the valve element between a closed position in which the valve element contacts the valve seat and an open position in which the valve element is spaced from the valve seat. The actuator may be a pneumatic actuator, an electric actuator, or another type of actuator. The control device 3 (see FIG. 3) controls the actuator to open and close the gas valve 25v.

[0056] Next, the pre-bonding cleaning unit 30 will be described.

[0057] Fig. 6A is a schematic diagram of the interior of the pre-bonding cleaning unit 30 as viewed horizontally. Fig. 6B is a schematic diagram of the interior of the pre-bonding cleaning unit 30 as viewed from directly above.

[0058] 6A and 6B , the pre-bonding cleaning unit 30 includes a chamber 31 forming an internal space in which the substrate W is placed and a passage port through which the substrate W passes to enter and exit the internal space, a chuck 34 for horizontally holding the substrate W within the chamber 31, an electric motor 35 for rotating the chuck 34 to rotate the substrate W about a vertical rotation center A1 passing through the center of the substrate W held by the chuck 34, and one or more processing liquid nozzles 36 for discharging a processing liquid such as a cleaning liquid toward the substrate W held by the chuck 34. The chamber 31 includes a partition wall 32 forming the internal space and the passage port, and a door 33 that moves relative to the partition wall 32 to open and close the passage port. The cleaning liquid may be pure water (deionized water (DIW)) or a liquid other than pure water.

[0059] Although not shown, the post-grinding cleaning unit 70 (see FIG. 3) has a configuration similar to that of the pre-bonding cleaning unit 30. Therefore, the post-grinding cleaning unit 70 includes a chamber 31, a chuck 34, an electric motor 35, and a processing liquid nozzle 36. The chamber 31 includes a partition wall 32 and a door 33. The pre-bonding cleaning unit 30 and the post-grinding cleaning unit 70 differ from each other in that the pre-bonding cleaning unit 30 cleans the first substrate W1 or the second substrate W2, whereas the post-grinding cleaning unit 70 cleans the first substrate W1 or the second substrate W2 that has been bonded and ground.

[0060] Next, the coating unit 40 will be described.

[0061] Fig. 7A is a schematic diagram of the interior of the coating unit 40 as viewed horizontally. Fig. 7B is a schematic diagram of the interior of the coating unit 40 as viewed from directly above. Figs. 7C and 7D are schematic diagrams of the filling liquid nozzle 49.

[0062] The application unit 40 includes a pre-bonded aligner. The pre-bonded aligner has a configuration similar to the pre-activated aligner 10 (see FIGS. 4A and 4B ). Therefore, the application unit 40 includes a chamber 11, a partition 12, a door 13, a chuck 14, an electric motor 15, and an outer periphery position sensor 16. In the following, to distinguish between the configuration of the pre-activated aligner 10 and the configuration of the application unit 40, the chamber 11, partition 12, door 13, chuck 14, electric motor 15, and outer periphery position sensor 16 for the application unit 40 will be referred to as a chamber 41, a partition 42, a door 43, a chuck 44, an electric motor 45, and an outer periphery position sensor 46. The chuck 44 is the vacuum chuck described above.

[0063] The coating unit 40 includes at least one filling liquid nozzle 49 that ejects filling liquid toward the substrate W held by the chuck 44. Fig. 7B shows an example in which two filling liquid nozzles 49 are provided. The two filling liquid nozzles 49 are arranged at an interval in the rotation direction Dr of the chuck 44. The two filling liquid nozzles 49 eject filling liquid toward two target positions spaced apart in the rotation direction Dr of the chuck 44. Each target position is a position within the annular groove WG (see Fig. 1C).

[0064] Filler liquid nozzle 49 is a droplet nozzle that generates multiple droplets of filler liquid that are sprayed toward the object to be coated. The droplet nozzle may be a mist nozzle that ejects liquid in a mist, an inkjet nozzle that forms a line of multiple droplets, or other types of nozzles. Figures 7C and 7D show an example in which filler liquid nozzle 49 is an inkjet nozzle.

[0065] The mist nozzle may be an external-mixing or internal-mixing two-fluid nozzle that generates mist by colliding liquid and gas, or a spray nozzle that generates mist by discharging compressed liquid from an orifice or by utilizing the Venturi effect.

[0066] The inkjet nozzle may be a piezoelectric or thermal inkjet nozzle, or may be an inkjet nozzle other than a piezoelectric or thermal type. The inkjet nozzle may be a large-diameter nozzle 49X having a relatively large diameter nozzle 49x for ejecting droplets, or a small-diameter nozzle 49Y having a relatively small diameter nozzle 49y for ejecting droplets.

[0067] FIG. 7C shows an example of a large-diameter nozzle 49X. FIG. 7D shows an example of a small-diameter nozzle 49Y. The diameter of the injection port 49x of the large-diameter nozzle 49X may be within any of the ranges of 10 μm or less, 8 μm or less, and 3 μm or less, or may be outside these ranges. The same applies to the diameter of the injection port 49y of the small-diameter nozzle 49Y. The area of ​​the injection port 49y of the small-diameter nozzle 49Y is smaller than the area of ​​the injection port 49x of the large-diameter nozzle 49X. When the diameter of the injection port 49x of the large-diameter nozzle 49X exceeds 10 μm, the diameter of the injection port 49y of the small-diameter nozzle 49Y may be within the range of 0.01 μm to 10 μm.

[0068] The filling liquid nozzle 49 may be fixed to the partition wall 42 or may be movable relative to the partition wall 42. When multiple filling liquid nozzles 49 are provided in one application unit 40, at least one filling liquid nozzle 49 may be fixed to the partition wall 42 and the remaining at least one filling liquid nozzle 49 may be movable relative to the partition wall 42.

[0069] 7A and 7B , when the filling liquid nozzles 49 are movable relative to the partition walls 42, the application unit 40 may include nozzle actuators 49a that move the filling liquid nozzles 49 relative to the partition walls 42. One nozzle actuator 49a may be provided for each filling liquid nozzle 49, or one nozzle actuator 49a may be provided for each of a plurality of filling liquid nozzles 49. FIGS. 7A and 7B show an example of the former.

[0070] The nozzle actuator 49a may include at least one of a horizontal actuator that moves the filling liquid nozzle 49 horizontally, a vertical actuator that moves the filling liquid nozzle 49 vertically, and an attitude-changing actuator that changes the attitude of the filling liquid nozzle 49. When moving the filling liquid nozzle 49 in the horizontal and vertical directions, the filling liquid nozzle 49 may be directly or indirectly connected to the horizontal actuator, and the horizontal actuator may be directly or indirectly connected to the vertical actuator.

[0071] 7A and 7B, the coating unit 40 includes a height sensor 47 that measures the height of the substrate W held by the chuck 44. The height sensor 47 measures the height of the upper or lower surface of the substrate W held by the chuck 44. Fig. 7A shows an example in which the height sensor 47 is disposed above the substrate W held by the chuck 44 and measures the height of the upper surface of the substrate W. The height sensor 47 may be a laser sensor or another sensor.

[0072] The height sensor 47 is an optical non-contact sensor that detects the vertical position of the substrate W. When the chuck 44 rotates around the rotation center A1 of the chuck 44 while holding the substrate W, the substrate W moves in the rotation direction Dr of the chuck 44 relative to the height sensor 47, and the position detected by the height sensor 47 moves in the opposite direction to the rotation direction Dr of the chuck 44 relative to the substrate W. Therefore, if the substrate W and the chuck 44 are rotated 360 degrees or more while the height sensor 47 is measuring the height of the substrate W, the height of the substrate W can be measured around the entire circumference of the substrate W.

[0073] By measuring the height of the upper surface of the substrate W over the entire circumference of the substrate W, it is possible to measure the shape of the upper surface of the substrate W over the entire circumference of the substrate W. For example, by measuring the height of the outer periphery of the upper surface of the substrate W, more specifically, the height in the range from the edge of the substrate W to a position inside the edge, over the entire circumference of the substrate W, it is possible to measure the shape of the outer periphery of the upper surface of the substrate W including the edge of the substrate W. Because the shape of the outer periphery of the upper surface of the substrate W is measured for each rotation angle about the rotation center A1 of the chuck 44, it is also possible to measure how the shape of the outer periphery of the upper surface of the substrate W changes depending on the position in the circumferential direction of the substrate W.

[0074] The outer periphery position sensor 46 is an optical non-contact sensor that detects the horizontal position of the outer periphery of the substrate W. When the chuck 44 rotates around the rotation center A1 of the chuck 44 while holding the substrate W, the substrate W moves in the rotation direction Dr of the chuck 44 relative to the outer periphery position sensor 46, and the position detected by the outer periphery position sensor 46 moves in the opposite direction to the rotation direction Dr of the chuck 44 relative to the substrate W. Therefore, if the substrate W and the chuck 44 are rotated 360 degrees or more while the outer periphery position sensor 46 is detecting the outer periphery position of the substrate W, the outer periphery position of the substrate W in the horizontal direction can be detected all around the circumference of the substrate W. This makes it possible to measure the shape of the outer periphery of the substrate W.

[0075] By measuring the shape of the outer periphery of the substrate W held by the chuck 44, it is possible to measure the amount and direction of eccentricity of the substrate W relative to the rotation center A1 of the chuck 44. It is also possible to measure the orientation of the notch or orientation flat relative to the chuck 44. In addition, because the position of the outer periphery of the substrate W is measured for each rotation angle about the rotation center A1 of the chuck 44, it is also possible to measure how the position of the outer periphery of the substrate W in the horizontal direction changes depending on the position of the substrate W in the circumferential direction.

[0076] The coating unit 40 includes a void detector 48 that captures an image of voids in at least one of the filling liquid and the filler in the annular groove WG (see FIG. 1C ) of the bonded substrate W (two bonded substrates W) held by the chuck 44. The void detector 48 may be an infrared camera or a camera other than an infrared camera, as long as it can capture an image of the voids in the filling liquid and the filler. When the void detector 48 is a camera, the image sensor may be either a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS).

[0077] When the void detector 48 is an infrared camera, the coating unit 40 may include a light source 48s (see FIG. 7A ) that irradiates the outer periphery of the bonded substrate W with infrared light. The light source 48s may be disposed inside or outside the coating unit 40. In the latter case, the light from the light source 48s may be guided into the coating unit 40 by a guide such as an optical fiber. If the presence or absence of voids in the filler liquid and filler can be detected without the light source 48s, the light source 48s is not necessary.

[0078] 7B shows an example in which one void detector 48 is provided for each filling liquid nozzle 49. Therefore, in this example, two void detectors 48 are provided. However, this is not limited to this, and one void detector 48 may be provided for each of a plurality of filling liquid nozzles 49. In the example shown in FIG. 7B, the void detector 48 is disposed upstream of the filling liquid nozzle 49 in the rotation direction Dr of the chuck 44. The filling liquid nozzle 49 and the void detector 48 may be disposed within a range of less than 45 degrees with respect to the angle around the rotation center A1 of the chuck 44.

[0079] The void detector 48 photographs the interior of the annular groove WG of the bonded substrate W. If at least one of the filler liquid and the filler is present in the annular groove WG, the void detector 48 also photographs the filler liquid and the filler. If the substrate W and the chuck 44 are rotated 360 degrees or more while the void detector 48 photographs the substrate W, the annular groove WG and the like are photographed over the entire circumference of the substrate W. This makes it possible to inspect the entire circumference of the substrate W for the presence or absence of voids in the filler liquid or filler supplied to the bonded substrate W. Furthermore, the void detector 48 can observe how the shape of the annular groove WG and the shapes of the filler liquid and the filler in the annular groove WG change depending on the circumferential position of the substrate W.

[0080] Next, a description will be given of the bonding unit 50. Unless otherwise specified, the bonding unit 50 described in this specification bonds substrates under atmospheric pressure.

[0081] 8A and 8B are horizontal schematic views of the inside of the bonding unit 50. Fig. 8A shows the state before the first substrate W1 and the second substrate W2 are bonded, and Fig. 8B shows the state after the first substrate W1 and the second substrate W2 have been bonded.

[0082] 8A and 8B , the bonding unit 50 includes a chamber 51 that forms a passage opening through which the first substrate W1 and the second substrate W2 pass before and after bonding and an internal space in which the first substrate W1 and the second substrate W2 that have passed through the passage opening are placed, a first chuck 54A that holds the first substrate W1 horizontally within the chamber 51, and a second chuck 54B that holds the second substrate W2 horizontally within the chamber 51. The chamber 51 includes a partition wall 52 that forms the internal space and the passage opening, and a door 53 that moves relative to the partition wall 52 to open and close the passage opening.

[0083] The bonding unit 50 further includes a plurality of bonding actuators 55 that bond the first substrate W1 and the second substrate W2 by moving the first chuck 54A and the second chuck 54B relative to each other while they are holding the first substrate W1 and the second substrate W2, and at least one camera 56 that detects the alignment of the first substrate W1 and the second substrate W2 at least either before or after bonding the first substrate W1 and the second substrate W2 by photographing at least one of the first substrate W1 and the second substrate W2.

[0084] The multiple joining actuators 55 may include a horizontal actuator that moves the first chuck 54A and the second chuck 54B relatively in the horizontal direction, a vertical actuator that moves the first chuck 54A and the second chuck 54B relatively in the vertical direction, and a rotational actuator that rotates the first chuck 54A and the second chuck 54B relatively around a vertical line.

[0085] The multiple bonding actuators 55 may include an inversion actuator that rotates the first chuck 54A about a horizontal line to invert the first substrate W1 held by the first chuck 54A upside down. The inversion actuator may also invert the first substrate W1 held by a chuck other than the first chuck 54A upside down. The inversion actuator may also invert the first substrate W1 upside down outside the bonding unit 50. When the hand TH (see FIG. 3) of the transport robot TR can hold the first substrate W1 horizontally facing downward (when the hand TH is a vacuum hand, Bernoulli hand, or the like), the inversion actuator may be part of the transport robot TR.

[0086] The at least one camera 56 may include a first camera 56A that photographs the first substrate W1 before it is bonded to the second substrate W2, a second camera 56B that photographs the second substrate W2 before it is bonded to the first substrate W1, and a third camera 56C that photographs the bonded first substrate W1 and second substrate W2. The first camera 56A may photograph the first substrate W1 held by the first chuck 54A, or may photograph the first substrate W1 held by a chuck other than the first chuck 54A. The same applies to the second camera 56B. The third camera 56C may photograph the bonded substrate W (bonded first substrate W1 and second substrate W2) held by the first chuck 54A or the second chuck 54B, or may photograph the bonded substrate W held by a chuck other than the first chuck 54A or the second chuck 54B. At least one camera 56 may capture an image of at least one of the first substrate W1 and the second substrate W2 outside the bonding unit 50.

[0087] The first camera 56A and the second camera 56B are alignment cameras used to check and adjust the alignment of the first substrate W1 and the second substrate W2 before they are bonded. The third camera 56C is an inspection camera used to check the alignment of the bonded first substrate W1 and the second substrate W2. The inspection camera is an infrared camera that converts infrared light into an electrical signal to generate electronic data of still images or videos. The alignment camera may be an infrared camera or a visible light camera that converts visible light into an electrical signal to generate electronic data of still images or videos.

[0088] Next, the grinding unit 60 will be described.

[0089] Fig. 9A is a schematic diagram of the interior of the grinding unit 60 as seen horizontally. Fig. 9B is a schematic diagram of the interior of the grinding unit 60 as seen from directly above.

[0090] 9A and 9B , grinding unit 60 includes a chamber 61 that forms a passage opening through which bonded substrate W, i.e., bonded first substrate W1 and second substrate W2, passes and an internal space in which bonded substrate W that has passed the passage opening is placed, a chuck 64 that holds bonded substrate W horizontally within chamber 61, and an electric motor 65 that rotates chuck 64 to rotate bonded substrate W about a vertical center of rotation A1 that passes through the center of bonded substrate W held by chuck 64. Chamber 61 includes a partition wall 62 that forms the internal space and the passage opening, and a door 63 that moves relative to partition wall 62 to open and close the passage opening.

[0091] Grinding unit 60 further includes a grindstone 66 that is pressed against the upper surface of bonded substrate W held by chuck 64, a horizontal, disc-shaped wheel 67 that holds grindstone 66, an electric motor 68 that rotates grindstone 66 and wheel 67 around a vertical center of rotation that passes through the center of wheel 67, and an elevation actuator 69 that vertically moves grindstone 66 and wheel 67. When grindstone 66 is brought into contact with the upper surface of bonded substrate W while rotating chuck 64 and wheel 67, the entire upper surface of bonded substrate W is ground by grindstone 66.

[0092] Next, the electrical configuration of the substrate bonding apparatus 1 will be described.

[0093] 10 is a block diagram showing the electrical configuration of the substrate bonding apparatus 1. The substrate bonding apparatus 1 includes a control device 3 that controls the electrical and electronic devices provided in the substrate bonding apparatus 1. The control device 3 controls the substrate bonding apparatus 1 to operate as described below. In other words, the control device 3 is programmed to perform the operations described below.

[0094] The control device 3 includes at least one computer. The computer includes a computer main body 3a and a peripheral device 3d connected to the computer main body 3a. The computer main body 3a includes a CPU 3b (central processing unit) that executes various instructions and a memory 3c that stores information. The peripheral device 3d includes a storage 3e that stores information to be transmitted and received between the memory 3c, such as a program P, a reader 3f that reads information from removable media RM, and a communication device 3g that communicates with other devices, such as a host computer HC. The memory 3c and the storage 3e are both examples of storage devices that store information to be transmitted and received between the CPU 3b and the CPU 3b.

[0095] The control device 3 is connected to an input device 3h and a display device 3i. The input device 3h is operated when an operator such as a user or a maintenance technician inputs information into the substrate bonding apparatus 1. The information is displayed on the screen of the display device 3i. The input device 3h may be any of a keyboard, a pointing device, and a touch panel, or may be a device other than these. The substrate bonding apparatus 1 may be provided with a touch panel display that serves as both the input device 3h and the display device 3i.

[0096] The CPU 3b executes a program P stored in the storage 3e. The program P in the storage 3e may be one that has been pre-installed in the control device 3, one that has been sent from a removable medium RM to the storage 3e via the reader 3f, or one that has been sent to the storage 3e from an external device such as a host computer HC via a communication device 3g.

[0097] The memory 3c is a volatile memory that retains its memory only when power is supplied. The storage 3e and the removable medium RM are non-volatile memories that retain their memory even when power is not supplied. The storage 3e is, for example, a magnetic storage device such as a hard disk drive. The removable medium RM is, for example, an optical disk such as a compact disk or a semiconductor memory such as a memory card. The removable medium RM is an example of a computer-readable recording medium on which the program P is recorded. The removable medium RM is a non-transitory tangible recording medium.

[0098] The storage 3e stores a plurality of recipes RC. The recipes RC are information that specifies the processing content, processing conditions, and processing procedures for the substrates W. The plurality of recipes RC differ from one another in at least one of the processing content, processing conditions, and processing procedures for the substrates W. The control device 3 controls the substrate bonding apparatus 1 so that the substrates W are processed in accordance with the recipes RC specified by the host computer HC. The control device 3 is programmed to execute each of the processes described below.

[0099] The recipe RC includes the application amount (total amount of filler liquid supplied to one substrate W), the application start position (position where supply of filler liquid to the substrate W starts), and the application end position (position where supply of filler liquid to the substrate W starts to end). In other words, the application amount, etc. are specified in the recipe RC. When the filling liquid nozzle 49 is moved, the path through which the filling liquid nozzle 49 passes is also included in the recipe RC. The user can change the application amount, etc. by editing the recipe RC. The recipe RC may be edited by the user operating the input device 3h, or by the user operating a device other than the substrate bonding apparatus 1, such as a personal computer. In the latter case, the edited recipe RC can be sent to the control device 3 via the communication device 3g.

[0100] Next, a description will be given of application of the filler liquid to the substrate W. First, the shape of the substrate W will be described, and then application of the filler liquid to the substrate W will be described.

[0101] Fig. 11A is a schematic cross-sectional view of the outer periphery of a substrate W. Fig. 11B is a schematic view of the inside of the coating unit 40 as seen from directly above. Fig. 11C is a schematic cross-sectional view showing a state in which fill liquid FL is being supplied to an annular groove WG formed between the outer peripheries of two bonded substrates W. Fig. 11D is a schematic cross-sectional view showing a state in which voids V1 and V2 between the two bonded substrates W are being detected by a void detector 48.

[0102] As described above, after two substrates W are bonded together, a filler liquid FL is applied to the outer peripheries of the two bonded substrates W. The outer peripheries of the substrates W are also called bevel portions. Fig. 11A shows an example in which the cross section of the outer peripheries of the substrate W is semicircular or parabolic. The cross section of the outer peripheries of the substrate W may have a shape other than semicircular or parabolic, such as a trapezoidal shape. The following describes a state in which the front and back surfaces of the substrate W are horizontal.

[0103] The outer surface of the substrate W includes a bonding surface WA that comes into contact with another substrate W, a non-bonding surface WN that does not come into contact with another substrate W, and a tip WE that is located outermost on the outer surface of the substrate W. The tip WE of the substrate W is a circular line or surface that connects the outer periphery of the bonding surface WA and the outer periphery of the non-bonding surface WN. The edge surface of the substrate W is a region of a predetermined range that includes the tip WE of the substrate W.

[0104] The bonding surface WA of the substrate W includes a horizontal, flat, circular flat portion F1 and an annular outer periphery O1 extending from the outer periphery of the flat portion F1 to the tip WE so as to descend as it approaches the tip WE. The non-bonding surface WN of the substrate W includes a horizontal, flat, circular flat portion F2 and an annular outer periphery O2 extending from the outer periphery of the flat portion F2 to the tip WE so as to ascend as it approaches the tip WE.

[0105] The flat portion F1 of the bonding surface WA corresponds to a device formation region where a device is formed. The flat portion F1 of the bonding surface WA is parallel to the flat portion F2 of the non-bonding surface WN. The center of the flat portion F1 of the bonding surface WA is located on the center line of the substrate W. The same is true for the center of the flat portion F2 of the non-bonding surface WN. The diameter of the flat portion F1 of the bonding surface WA is equal to or approximately equal to the diameter of the flat portion F2 of the non-bonding surface WN. When the cross section of the outer periphery of the substrate W is semicircular or parabolic, the cross sections of the outer periphery O1 and O2 are arc-shaped. When the cross section of the outer periphery of the substrate W is trapezoidal, the cross sections of the outer periphery O1 and O2 are linear.

[0106] 11A , when two substrates W are bonded together, the outer peripheries of the two bonded substrates W form an annular groove WG that opens at the edge faces of the two substrates W. The annular groove WG is formed between the two bonded substrates W by the outer peripheries of the two substrates W. The annular groove WG is continuous around the entire periphery of the bonded substrate W. The thickness direction of the two bonded substrates W corresponds to the width direction of the annular groove WG, and the radial direction of the two bonded substrates W (the direction perpendicular to the center line of the substrates W) corresponds to the depth direction of the annular groove WG. The depth of the annular groove WG increases continuously or stepwise as one approaches the center of the annular groove WG in the width direction of the annular groove WG.

[0107] As described above, after two substrates W are bonded together, the bonded substrate W, i.e., one of the two bonded substrates W, is ground down using a grindstone 66 (see FIG. 9A ). The thickness of the outer periphery of the substrate W decreases toward the edge of the substrate W. Near the edge of the substrate W, the outer peripheries of the two bonded substrates W are separated from each other, forming a gap corresponding to the annular groove WG. If the bonded substrate W is ground without a filler FS (see FIG. 11D ) in the annular groove WG, a force is applied to the outer periphery of the substrate W from the grindstone 66, which may cause the outer periphery of one substrate W to bend toward the outer periphery of the other substrate W. To mitigate this, a filler liquid FL that changes into a solid or semi-solid filler FS must be supplied to the annular groove WG.

[0108] 11B, when the filling liquid FL is supplied to the annular groove WG of the bonded substrate W, the bonded substrate W is carried into the coating unit 40 by the transport robot TR (see FIG. 3) and held horizontally by the chuck 44. This allows the substrate W to be held horizontally with the front surface of the substrate W, which is the bonding surface WA, facing upward. In this state, the substrate W is rotated by the chuck 44, and the filling liquid FL is discharged from the filling liquid nozzle 49 toward the annular groove WG of the bonded substrate W.

[0109] The filler liquid FL ejected from the filler liquid nozzle 49 is applied to the inner surface of the annular groove WG. Fig. 11C shows an example in which the filler liquid nozzle 49 is an inkjet nozzle. In this example, multiple droplets of the filler liquid FL ejected from the filler liquid nozzle 49 are scattered in approximately the same direction toward the annular groove WG of the bonded substrate W. These droplets enter the annular groove WG and collide with the bonded substrate W within the annular groove WG. As a result, the filler liquid FL is applied to the inner surface of the annular groove WG.

[0110] The droplets of filler liquid FL applied to the bonded substrate W remain at or near the position where they collided with the bonded substrate W due to the viscosity of the filler liquid FL and the force acting on the filler liquid FL from the bonded substrate W. Subsequent droplets of filler liquid FL collide with at least one of the inner surface of the annular groove WG and the filler liquid FL adhering to the inner surface of the annular groove WG, and remain at or near the position where they collided. As this phenomenon is repeated, the filler liquid FL gradually reduces the space within the annular groove WG, i.e., the space between the outer peripheries of the two bonded substrates W.

[0111] The filler liquid FL in the annular groove WG changes into a solid or semi-solid filler FS within the annular groove WG. If the filler liquid FL has changed into the filler FS when grinding of the bonded substrate W begins, the filler liquid FL may change into the filler FS while the filler liquid nozzle 49 is discharging the filler liquid FL, or may change into the filler FS after the filler liquid nozzle 49 stops discharging the filler liquid FL. In either case, a process may be performed to cause or promote the change from the filler liquid FL to the filler FS.

[0112] The filling liquid nozzle 49 may be kept stationary or may be kept moving from the start to the end of the discharge of the filling liquid FL from the filling liquid nozzle 49. There may be a period in which the filling liquid nozzle 49 is made to discharge the filling liquid FL while the filling liquid nozzle 49 is kept stationary, and a period in which the filling liquid nozzle 49 is made to discharge the filling liquid FL while the filling liquid nozzle 49 is moving.

[0113] The radial distance from the center of rotation A1 of the bonded substrate W to the outer periphery of the bonded substrate W can change depending on the angle around the center of rotation A1 of the bonded substrate W. The height of the outer periphery of the bonded substrate W can also change depending on the angle around the center of rotation A1 of the bonded substrate W. Therefore, the position of the annular groove WG can change in at least one of the radial and vertical directions depending on the angle around the center of rotation A1 of the bonded substrate W.

[0114] 11C , the control device 3 may reduce the change in the distance from the filling liquid nozzle 49 to the annular groove WG of the bonded substrate W by causing the nozzle actuator 49a to move the filling liquid nozzle 49 in response to a change in the position of the annular groove WG in at least one of the radial and vertical directions. In this case, the control device 3 may measure the change in the position of the annular groove WG over the entire circumference of the bonded substrate W and then cause the filling liquid nozzle 49 to start discharging the filling liquid FL toward the rotating bonded substrate W, or may cause the filling liquid nozzle 49 to discharge the filling liquid FL toward the rotating bonded substrate W while measuring the change in the position of the annular groove WG.

[0115] The outer periphery position sensor 46, the height sensor 47, and the void detector 48 are examples of position detectors that detect the position of the outer periphery of the bonded substrate W. Changes in the position of the annular groove WG may be detected by any one of the outer periphery position sensor 46, the height sensor 47, and the void detector 48, or by two or more of them. The void detector 48 can also detect changes in the position of the annular groove WG in the radial and vertical directions by detecting changes in the shape of the annular groove WG relative to the angle around the center of rotation A1 of the bonded substrate W.

[0116] 11B shows an example in which the filling liquid nozzle 49 is caused to discharge the filling liquid FL toward the rotating bonded substrate W while measuring changes in the position and shape of the annular groove WG with the void detector 48. In this example, the void detector 48 is disposed upstream of the filling liquid nozzle 49 in the rotation direction Dr of the bonded substrate W. Since the difference in rotation angle between the void detector 48 and the filling liquid nozzle 49 (the difference in angle about the rotation center A1 of the bonded substrate W) and the rotation speed of the bonded substrate W are known, the filling liquid nozzle 49 can be moved relative to the bonded substrate W in accordance with these and the amount and direction of change in the position of the annular groove WG.

[0117] Not only the position of the annular groove WG but also the shape of the annular groove WG can change depending on the angle around the rotation center A1 of the bonded substrate W. When measuring changes in the position and shape of the annular groove WG using the void detector 48, the flow rate of the filler liquid FL discharged from the filler liquid nozzle 49 (the amount of filler liquid FL discharged from the filler liquid nozzle 49 per unit time) may be changed in response to the changes. This can reduce changes in the radial distance from the rotation center A1 of the bonded substrate W to the outer end of the filler liquid FL in the annular groove WG. The control device 3 may change the flow rate of the filler liquid FL regardless of whether or not changes in the position and shape of the annular groove WG are measured.

[0118] When filling liquid FL is applied to a plurality of bonded substrates W, the position of the annular groove WG may change in the same manner among these bonded substrates W. Therefore, the control device 3 may cause the nozzle actuator 49a to move the filling liquid nozzle 49 in accordance with the change in the position of the annular groove WG of another bonded substrate W. In other words, the control device 3 may store measurement data D1 obtained when measuring the change in the position of the annular groove WG of another bonded substrate W, and cause the nozzle actuator 49a to move the filling liquid nozzle 49 based on this measurement data D1. Alternatively, the control device 3 may cause the void detector 48 or the like to measure the change in the position and shape of the annular groove WG each time the bonded substrate W held by the chuck 44 is changed.

[0119] In this manner, the filler liquid FL is applied to the inner surface of the annular groove WG. After the supply of the filler liquid FL is stopped, the inside of the annular groove WG may be observed with the void detector 48 to detect the presence or absence of coating defects. As shown in FIG. 11D , the void detector 48 can detect voids V1 in the filler liquid FL or filler FS in the annular groove WG of the bonded substrate W held by the chuck 44. The void detector 48 may be configured to detect voids V2 between the bonding surfaces WA1 and WA2. To detect voids V2, the void detector 48 may be moved above or below the bonded substrate W held by the chuck 44, or another void detector 48 may be positioned above or below the bonded substrate W held by the chuck 44.

[0120] When two substrates W are bonded together, a gap corresponding to the annular groove WG is formed between the outer peripheries of the two substrates W. When two substrates W without a filler FS in the annular groove WG are being ground, a force is applied from the grindstone to the outer periphery of the substrate W, which can cause the outer periphery of the substrate W to bend toward the annular groove WG. By placing a filler FS in the annular groove WG, such bending can be reduced. A void V1 (see FIG. 11D ) within the filler FS can cause stress concentration in the filler FS when two substrates W are being ground. The void V1 can be reduced or made smaller by supplying droplets of filler liquid FL to the annular groove WG.

[0121] After the annular groove WG is filled with the filler liquid FL, the bonded substrate W is ground. When grinding of the bonded substrate W begins, the filler liquid FL in the annular groove WG has changed into a solid or semi-solid filler FS. When the bonded substrate W, i.e., one of the two bonded substrates W, is ground with a grindstone 66 (see FIG. 9A ), the outer periphery of the bonded substrate W is supported by the filler FS. Therefore, chipping, in which the edge of the thinned substrate W breaks off, and the associated generation of particles can be prevented or reduced. As a result, the number of particles adhering to devices can be reduced, and device yield can be increased.

[0122] Next, the effects of this embodiment will be described.

[0123] In this embodiment, while the bonded substrate W is being rotated, multiple droplets of filler liquid are sprayed toward the annular groove WG formed between the outer peripheries of the two bonded substrates W. This allows the filler liquid to be supplied to the annular groove WG. In addition, the range of the filler liquid supplied to the annular groove WG can be controlled by controlling the rotation angle of the chuck 44 holding the bonded substrate W. The filler liquid changes into a solid or semi-solid filler. Therefore, the filler can restrict the relative movement of the outer peripheries of the two bonded substrates W. Furthermore, because multiple droplets of filler liquid are sprayed, the amount of filler liquid supplied to the annular groove WG can be more precisely controlled than when the filler liquid is continuously sprayed.

[0124] In this embodiment, droplets of filler liquid are intermittently sprayed from the filler liquid nozzle 49, which is an inkjet nozzle. The multiple droplets of filler liquid sprayed from the filler liquid nozzle 49 fly in the same or almost the same direction toward the annular groove WG. Therefore, the position where the filler liquid is supplied can be controlled with greater precision than when multiple droplets of filler liquid fly in various directions.

[0125] In this embodiment, the position of the outer periphery of the bonded substrate W held by the chuck 44 is detected, and the nozzle actuator 49a is caused to move the filler liquid nozzle 49 in accordance with the detected position. This causes the filler liquid nozzle 49 to move in at least one of the horizontal and vertical directions in accordance with changes in the position of the outer periphery of the bonded substrate W, thereby minimizing changes in the distance from the filler liquid nozzle 49 to the bonded substrate W that occur as the bonded substrate W rotates. This allows for accurate control of the position to which the filler liquid is supplied. When the amount of filler liquid FL discharged per unit time from the filler liquid nozzle 49 is changed in accordance with the detected position, changes in the radial distance from the rotation center A1 of the bonded substrate W to the outer edge of the filler liquid FL in the annular groove WG can be reduced.

[0126] In this embodiment, the nozzle actuator 49a moves the filling liquid nozzle 49 while detecting the position of the outer periphery of the bonded substrate W, rather than after detecting the position of the outer periphery of the bonded substrate W. Therefore, the time required to complete the supply of filling liquid to the annular groove WG can be shortened compared to when the nozzle actuator 49a moves the filling liquid nozzle 49 after detection of the position of the outer periphery of the bonded substrate W has been completed but before the detection is being performed.

[0127] In this embodiment, while the chuck 44 holds the bonded substrate W, the void detector 48 detects voids in the filling liquid or filler in the annular groove WG. This makes it possible to detect voids in the filling liquid or filler in the annular groove WG while the filling liquid is being supplied to the annular groove WG. In addition, the void detector 48 can be configured to detect not only voids in the filling liquid or filler but also voids between the bonding surfaces WA of the two bonded substrates W. This shortens the time required to complete void detection compared to detecting voids between the bonding surfaces WA of the two substrates W after the bonded substrate W is moved from the chuck 44.

[0128] In this embodiment, a coating unit 40 is provided in a substrate bonding apparatus 1 that bonds two substrates W. The coating unit 40 coats the two substrates W bonded by the bonding unit 50 with filler liquid. As described above, the coating unit 40 sprays a plurality of droplets of filler liquid toward the annular groove WG formed between the outer peripheries of the two bonded substrates W while rotating the bonded substrates W. This not only shortens the time from bonding the two substrates W to supplying the filler liquid to the two bonded substrates W, but also enables precise control of the amount of filler liquid supplied to the annular groove WG.

[0129] In this embodiment, the substrate bonding apparatus 1 is provided with not only the bonding unit 50 and the coating unit 40, but also a grinding unit 60 that grinds the bonded substrates W coated with the filler liquid. This reduces the time required from bonding two substrates W to grinding the two bonded substrates W. The filler liquid applied to the bonded substrates W changes into a solid or semi-solid filler. This allows the bonded substrates W to be ground while preventing the outer peripheries of the substrates W from being bent by the force applied by the grindstone 66.

[0130] Next, another embodiment will be described.

[0131] As shown in FIG. 12A, the application unit 40 may be integrated with the bonding unit 50 rather than being a pre-bonding aligner.

[0132] 8A and 8B. Therefore, the coating unit 40 includes a first chuck 54A, a second chuck 54B, a bonding actuator 55, etc. The first chuck 54A, the second chuck 54B, the chuck 44, etc. are disposed in the chamber 41 of the coating unit 40.

[0133] When the coating unit 40 is integrated with the bonding unit 50, after the first substrate W1 held by the first chuck 54A and the second substrate W2 held by the second chuck 54B are bonded, the first substrate W1 and the second substrate W2 are held by the second chuck 54B so that the first substrate W1 is positioned above the second substrate W2. The bonding actuator 55 horizontally moves the second chuck 54B between an imaging position (center position) where the bonded substrate W held by the second chuck 54B is imaged by the third camera 56C, a bonding position (left position) where the first substrate W1 held by the first chuck 54A is bonded to the second substrate W2 held by the second chuck 54B, and a receiving position (right position) where the bonded substrate W is received by the second chuck 54B or the chuck 44.

[0134] The chuck 44 has an adsorption surface that contacts the bonded substrate W facing downward. The coating unit 40 includes a chuck lifting actuator 44a that moves the chuck 44 vertically. The chuck lifting actuator 44a moves the chuck 44 vertically between a receiving position where the substrate W is received by the second chuck 54B or the chuck 44, and an application position (position shown in FIG. 12A ) where the filler liquid is applied to the bonded substrate W held by the chuck 44. The application position is a position above the receiving position. The receiving position of the chuck 44 is a position above the receiving position of the second chuck 54B.

[0135] The bonded substrate W held by the second chuck 54B is received by the chuck 44 when the second chuck 54B and the chuck 44 are located at the receiving position. The chuck 44 rises from the receiving position to the application position while holding the bonded substrate W. Thereafter, the filling liquid is supplied to the annular groove WG of the bonded substrate W held by the chuck 44. When the supply of the filling liquid starts, the second chuck 54B may be located at the receiving position or may be retracted from the receiving position.

[0136] The supply of filling liquid to the annular groove WG is the same as described above, except that the bonded substrate W is positioned below the chuck 44. If necessary, the position of the outer periphery of the bonded substrate W held by the chuck 44 may be detected by at least one of the outer periphery position sensor 46, the height sensor 47, and the void detector 48 shown in Figures 7A and 7B. After the supply of filling liquid to the annular groove WG is completed, the transport robot TR (see Figure 3) may receive the bonded substrate W from the chuck 44 located at any position within the range from the receiving position to the application position, or may receive the bonded substrate W from the second chuck 54B located at any position within the range from the receiving position to the imaging position.

[0137] 12B , after the filling liquid FL is supplied to the annular groove WG, the bonded substrate W held by the second chuck 54B may be photographed by the third camera 56C, which is an infrared camera. Specifically, after the bonded substrate W held by the chuck 44 is received by the second chuck 54B, the second chuck 54B may be moved from the receiving position to the photographing position. The bonded substrate W held by the second chuck 54B may then be photographed by the third camera 56C. In this case, the third camera 56C may detect not only the gap V2 between the bonding surfaces WA1 and WA2, but also the gap V1 within the filling liquid FL or filler FS in the annular groove WG.

[0138] 12A , the chamber 41 of the coating unit 40 accommodates not only the chuck 44 and the filling liquid nozzle 49, but also the first chuck 54A and the second chuck 54B of the bonding unit 50. This allows the substrate bonding apparatus 1 to be more compact than when a dedicated chamber 51 is provided for the bonding unit 50. In addition, since the filling liquid is supplied to the bonded substrate W held by a chuck 44 separate from the first chuck 54A and the second chuck 54B, the filling liquid nozzle 49 can be located away from the first chuck 54A and the second chuck 54B, making it difficult for the filling liquid to adhere to the first chuck 54A and the second chuck 54B.

[0139] 12B , the void detector 48 detects not only voids between the bonding surfaces WA of the two bonded substrates W, but also voids within the fill liquid or filler in the annular groove WG. In other words, the void detector 48 that detects voids between the two substrates W can also be used as a void detector 48 that detects voids within the fill liquid or filler. Therefore, it is not necessary to provide a dedicated void detector 48 that detects only voids within the fill liquid or filler in the annular groove WG.

[0140] 13 , the filling liquid may be applied only to a partial area in the circumferential direction of the substrate W, rather than being applied to the entire periphery of the substrate W. The area surrounded by the two-dot chain line in Fig. 13 indicates the area to which the filling liquid is applied. In this example, the filling liquid is applied only to four areas spaced apart in the circumferential direction of the substrate W.

[0141] Devices such as transistors are formed on the surface of the substrate W, which corresponds to the device formation surface. The device region and non-device region are both regions within the surface of the substrate W. In FIG. 13 , the outer edge of the device region is indicated by a thick line. The device region is a region where devices such as transistors and patterns exist. The non-device region is a region where no devices or patterns exist. The non-device region is a ring-shaped region around the device region.

[0142] The shortest distance from the outer periphery of the substrate W to the outer edge of the device region may vary depending on the position on the outer periphery of the substrate W. If this shortest distance is relatively short, a relatively large force is likely to be applied from the grinding wheel 66 (see FIG. 9A ) to devices located at the edge of the device region when the bonded substrate W is being ground. If cracks or chips that occur on the outer periphery of the bonded substrate W during grinding reach devices located at the edge of the device region, the devices (including the cracks, etc.) will become defective. The shorter this shortest distance, the more likely device defects will occur. As shown in FIG. 13 , the filler liquid may be applied only to multiple areas (areas surrounded by two-dot chain lines) where the shortest distance is relatively short. This prevents large forces from being applied to devices located at the edge of the device region, while shortening the time required to apply the filler liquid compared to applying the filler liquid to the entire periphery of the substrate W.

[0143] The filling liquid nozzle 49 may continuously eject the filling liquid so as to form a continuous liquid column from the filling liquid nozzle 49 to the substrate W, or may spray a plurality of droplets of the filling liquid toward the substrate W and then continuously eject the filling liquid so as to form a continuous liquid column from the filling liquid nozzle 49 to the substrate W. In the latter case, a droplet nozzle that sprays a plurality of droplets of the filling liquid toward the substrate W and a liquid column nozzle that continuously ejects the filling liquid so as to form a continuous liquid column from the filling liquid nozzle 49 to the substrate W may be provided.

[0144] If the filling liquid is continuously discharged so as to form a continuous liquid column from the filling liquid nozzle 49 to the substrate W after a plurality of droplets of the filling liquid are sprayed toward the substrate W, the position to which the filling liquid is supplied can be precisely controlled at first, and the filling liquid can be supplied at high speed thereafter. Therefore, the time required to complete the supply of the filling liquid can be shortened compared to the case where a plurality of droplets of the filling liquid are sprayed from start to finish.

[0145] The filler liquid nozzle 49 may be configured with a large-diameter nozzle 49X and a small-diameter nozzle 49Y as shown in FIGS. 7C and 7D . In this case, droplets of the filler liquid sprayed from the nozzle 49y of the small-diameter nozzle 49Y may be supplied to the bottom (deep) of the annular groove WG, i.e., a position that is difficult for the filler liquid to reach. Then, droplets of the filler liquid sprayed from the nozzle 49x of the large-diameter nozzle 49X may be supplied to the annular groove WG. This can reduce the likelihood of voids forming at the bottom of the annular groove WG and shorten the time required to apply the filler liquid.

[0146] Grinding unit 60 may be omitted from substrate bonding apparatus 1. Coating unit 40 may be omitted from substrate bonding apparatus 1. In other words, coating unit 40 may be a device separate from substrate bonding apparatus 1 and arranged outside outer wall 1 a of substrate bonding apparatus 1.

[0147] The substrate bonding apparatus 1 is not limited to an apparatus for bonding two disk-shaped substrates W, but may also be an apparatus for bonding two polygonal substrates W.

[0148] Any two or more of the above-described features may be combined. Any two or more of the above-described steps may be combined.

[0149] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples. The spirit and scope of the present invention are limited only by the appended claims.

[0150] This application claims priority based on Japanese Patent Application No. 2023-188940 filed on November 2, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. An application unit comprising: a chuck that holds a bonded substrate, which is two bonded substrates, and rotates about an axis that is perpendicular to a main surface of the bonded substrate and passes through the center of the main surface; and a filling liquid nozzle that supplies filling liquid to an annular groove formed between the outer peripheries of the two bonded substrates by spraying a plurality of droplets of filling liquid that changes into a solid or semi-solid filling body toward the bonded substrate held by the chuck.

2. The application unit according to claim 1, wherein the filler liquid nozzle is an inkjet nozzle that sprays a plurality of droplets of the filler liquid in substantially the same direction toward the annular groove.

3. The coating unit described in claim 1 or 2, further comprising: a position detector that detects the position of the outer periphery of the bonded substrate held by the chuck; and a nozzle actuator that moves the filling liquid nozzle in accordance with the position of the outer periphery detected by the position detector.

4. The application unit described in claim 3, further including a control device that performs at least one of the following: position control, in which the nozzle actuator moves the filling liquid nozzle in accordance with the position of the outer periphery detected by the position detector while causing the position detector to detect the position of the outer periphery; and flow rate control, in which the amount of the filling liquid sprayed per unit time from the filling liquid nozzle in accordance with the position of the outer periphery detected by the position detector while causing the position detector to detect the position of the outer periphery.

5. A coating unit as described in any one of claims 1 to 4, further comprising a void detector that detects voids within the filling liquid or filling body in the annular groove and voids between the bonding surfaces of the two bonded substrates when the chuck is holding the bonded substrates.

6. A coating unit as described in any one of claims 1 to 5, wherein the filling liquid nozzle includes a large-diameter nozzle that sprays multiple droplets of the filling liquid from a spray opening toward the bonded substrate held by the chuck, and a small-diameter nozzle that sprays multiple droplets of the filling liquid from a spray opening having an area smaller than the spray opening of the large-diameter nozzle toward the bonded substrate held by the chuck.

7. A substrate bonding device comprising: a bonding unit for bonding two substrates; and an application unit for applying a filling liquid that changes into a solid or semi-solid filling body to a bonded substrate, which is the two substrates bonded by the bonding unit, wherein the application unit includes: a chuck that holds the bonded substrate and rotates about an axis that is perpendicular to the main surface of the bonded substrate and passes through the center of the main surface; and a filling liquid nozzle that supplies the filling liquid to an annular groove formed between the outer peripheries of the two bonded substrates by spraying a plurality of droplets of the filling liquid toward the bonded substrate held by the chuck.

8. The substrate bonding apparatus of claim 7, wherein the bonding unit includes a first chuck and a second chuck for respectively holding the two substrates before being bonded, and a bonding actuator for bringing the two substrates held by the first chuck and the second chuck into contact with each other by moving the first chuck and the second chuck relatively, and the application unit further includes a chamber for accommodating the chuck, the filling liquid nozzle, and the first chuck and the second chuck.

9. The substrate bonding apparatus of claim 7 or 8, wherein the bonding unit further includes a void detector for detecting voids between the bonding surfaces of the two bonded substrates and voids within the filling liquid or filler in the annular groove.

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