Bonding substrate manufacturing method and bonding apparatus

Abstract

To efficiently manufacture a bonded substrate by ultrasonically inspecting the bonded state of the bonded substrate without deteriorating the bonded state. [Solution] A method for manufacturing a bonded substrate, comprising: a bonding step of bonding two substrates to form a bonded substrate; a sealing step of sealing the bonded interface exposed on the outer periphery of the bonded substrate from the atmosphere; and an inspection step of inspecting the bonded substrate. In the inspection step, ultrasonic inspection is carried out using an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium that transmits ultrasonic waves between the ultrasonic sensor and the bonded substrate. In the ultrasonic inspection, the medium is supplied from the supply nozzle to the underside of the bonded substrate, and ultrasonic waves are sent from the ultrasonic oscillator to the bonded substrate via the medium supplied to the underside of the bonded substrate, and the ultrasonic waves returning from the bonded substrate are received by the ultrasonic receiver.

Description

[Technical Field]

[0001] The present invention relates to a manufacturing method and a bonding apparatus for manufacturing a bonded substrate by bonding two substrates. [Background technology]

[0002] In the manufacturing process of semiconductor device chips installed in various electronic devices such as mobile phones and personal computers, two substrates such as semiconductor wafers are sometimes stacked and bonded to form a bonded substrate. If the two substrates in the manufactured bonded substrate are not properly bonded over the entire surface facing each other, for example, if a non-bonded area such as a gap occurs between the bonding surfaces of the substrates, problems such as peeling can easily occur in the films and functional layers that make up the substrates. In other words, this can result in the manufacture of low-quality semiconductor device chips.

[0003] Therefore, in a bonded substrate formed by bonding two substrates, the bonding state of the two substrates is inspected (see Patent Document 1). The bonded state is inspected by an infrared camera or ultrasonic testing. Ultrasonic testing allows for more detailed inspection of the bonded state and can detect even smaller bonding defects. However, when performing ultrasonic testing, it is necessary to supply a medium (liquid) such as pure water, which acts as a transmission medium for ultrasonic waves, between the inspection device and the bonded substrate. For example, ultrasonic testing is performed by submerging the bonded substrate in water.

[0004] When manufacturing a bonded substrate, a bonding process is performed to bond two substrates together, and a bond strengthening process is performed to strengthen the bond between the bonded substrates. If ultrasonic testing is performed before the bond strengthening process, water (medium) will get between the two substrates, deteriorating the bond. Therefore, the bond condition is inspected using an infrared camera before the bond strengthening process, and then using ultrasonic waves after the bond strengthening process.

[0005] If an infrared camera confirms that the bonded state does not meet the required quality before the bond strengthening process, the bonded substrates can be released and reused. On the other hand, if ultrasonic testing confirms that the bonded state does not meet the required quality after the bond strengthening process, it is difficult to release the bonded substrates without damaging each substrate, and the substrates cannot be reused. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-42431 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, if a bonding defect occurs that cannot be detected by an infrared camera but can be detected by ultrasonic testing, the bonding defect will not be detected before the bond strengthening process but will be detected after the bond strengthening process. If such a bonding defect is detected before the bond strengthening process, the bonded substrate can be disassembled to obtain substrates, allowing the substrates to be reused. Furthermore, if ultrasonic testing of the bonded substrate can be performed regardless of whether it is before or after the bond strengthening process, an infrared camera for inspecting the bonding state will be unnecessary, thereby reducing the manufacturing cost of the bonded substrate.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a method and a bonding apparatus for manufacturing a bonded substrate that can efficiently manufacture bonded substrates by ultrasonically inspecting the bonding state of the bonded substrates without deteriorating the bonding state. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a method for manufacturing a bonded substrate, comprising: a bonding step of bonding two substrates to form a bonded substrate; and an inspection step of inspecting the bonded substrate, wherein the inspection step involves performing an ultrasonic inspection using an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium that transmits ultrasonic waves between the ultrasonic sensor and the bonded substrate, wherein the medium is supplied from the supply nozzle to the underside of the bonded substrate, ultrasonic waves are sent from the ultrasonic oscillator to the bonded substrate through the medium supplied to the underside of the bonded substrate, and the ultrasonic waves returning from the bonded substrate are received by the ultrasonic receiver.

[0010] According to another aspect of the present invention, there is provided a method for manufacturing a bonded substrate, comprising: a bonding step of bonding two substrates to form a bonded substrate; a sealing step of sealing the bonded interface exposed on the outer periphery of the bonded substrate from the atmosphere; and an inspection step of inspecting the bonded substrate, wherein the inspection step is performed by an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium that transmits ultrasonic waves between the ultrasonic sensor and the bonded substrate, and wherein the ultrasonic inspection involves supplying the medium from the supply nozzle to the underside of the bonded substrate, transmitting ultrasonic waves from the ultrasonic oscillator to the bonded substrate through the medium supplied to the underside of the bonded substrate, and receiving the ultrasonic waves returning from the bonded substrate by the ultrasonic receiver.

[0011] According to yet another aspect of the present invention, there is provided a method for manufacturing a bonded substrate, comprising: a bonding step of bonding two substrates to form a bonded substrate; a sealing step of sealing the bonded interface exposed on the outer periphery of the bonded substrate from the atmosphere; and an inspection step of inspecting the bonded substrate, wherein the inspection step is performed by an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium that transmits ultrasonic waves between the ultrasonic sensor and the bonded substrate, and wherein the ultrasonic inspection involves supplying the medium from the supply nozzle to the bonded substrate, transmitting ultrasonic waves from the ultrasonic oscillator to the bonded substrate through the medium supplied to the bonded substrate, and receiving the ultrasonic waves returning from the bonded substrate by the ultrasonic receiver.

[0012] Preferably, the ultrasonic inspection is carried out with the bonded substrate in at least one of a rotated state, a vibrated state, and a tilted state relative to the supply nozzle.

[0013] Preferably, the method further comprises a plasma treatment step of plasma treating one or both of the surfaces to be bonded of the two substrates before the bonding step, and a bonding preparation step of supplying a fluid containing water to the plasma-treated surfaces to be bonded to form hydroxy groups on the surfaces to be bonded before the bonding step.

[0014] Preferably, the method further comprises, after the inspection step, a determination step of determining whether the bonded state of the bonded substrate is good or bad based on the inspection result of the inspection step, and a bond strengthening step of performing a process to strengthen the bond of the bonded substrate whose bonded state is determined to be good in the determination step.

[0015] Alternatively, after the inspection step, the method may further include a determination step of determining whether the bonded state of the bonded substrate is good or bad based on the inspection result of the inspection step, a separation step of separating the bonded substrate whose bonded state is determined to be poor in the determination step into two substrates, and a re-bonding step of bonding two new substrates including one or both of the two substrates obtained by separation in the separation step to form a new bonded substrate.

[0016] According to another aspect of the present invention, there is provided a bonding device comprising: a bonding portion for bonding two substrates together; and an inspection portion for inspecting the bonded substrates bonded at the bonding portion, wherein the inspection portion includes an ultrasonic inspection portion having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle for supplying a medium between the ultrasonic sensor and the bonded substrates, wherein the ultrasonic inspection portion supplies the medium from the supply nozzle to the underside of the bonded substrates, transmits ultrasonic waves from the ultrasonic oscillator to the bonded substrates through the medium supplied to the underside of the bonded substrates, and receives the ultrasonic waves returning from the bonded substrates with the ultrasonic receiver, thereby performing ultrasonic inspection.

[0017] According to another aspect of the present invention, there is provided a bonding device comprising: a joining portion for joining two substrates together; and an inspection portion for inspecting the bonded substrates joined at the joining portion, wherein the inspection portion has an ultrasonic inspection portion including a holding portion for holding the bonded substrates; a tube surrounding the bonded substrates and capable of expanding and contracting in response to internal pressure; an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver; and a supply nozzle for supplying a medium between the ultrasonic sensor and the bonded substrates, wherein the tube is connected to a pressure supply source for controlling the internal pressure, and the tube deforms when pressure is supplied from the pressure supply source to seal the bonded interface exposed at the outer periphery of the bonded substrates at the holding portion, and the ultrasonic inspection portion supplies the medium from the supply nozzle to the underside of the bonded substrates, transmits ultrasonic waves from the ultrasonic oscillator to the bonded substrate through the medium supplied to the underside of the bonded substrates, and receives the ultrasonic waves returning from the bonded substrates with the ultrasonic receiver, thereby performing ultrasonic inspection.

[0018] According to yet another aspect of the present invention, there is provided a bonding device comprising: a joining portion for joining two substrates together; and an inspection portion for inspecting the bonded substrates joined at the joining portion, wherein the inspection portion has an ultrasonic inspection portion including a holding portion for holding the bonded substrates; a tube surrounding the bonded substrates and capable of expanding and contracting in response to internal pressure; an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver; and a supply nozzle for supplying a medium between the ultrasonic sensor and the bonded substrates, wherein a pressure supply source for controlling the internal pressure is connected to the tube, and the tube deforms when pressure is supplied from the pressure supply source to seal the bonded interface exposed at the outer periphery of the bonded substrates at the holding portion, and the ultrasonic inspection portion supplies the medium from the supply nozzle to the bonded substrates, transmits ultrasonic waves from the ultrasonic oscillator to the bonded substrates through the medium supplied to the bonded substrates, and receives the ultrasonic waves returning from the bonded substrates with the ultrasonic receiver, thereby performing ultrasonic inspection.

[0019] Preferably, the inspection unit further includes one or more of a rotation unit that rotates the bonded substrate relative to the supply nozzle, a vibration unit that vibrates the bonded substrate, and a position change unit that positions the bonded substrate in an inclined position.

[0020] Preferably, the apparatus further comprises a plasma processing section that plasma-treats one or both of the surfaces to be bonded of the two substrates, and a bonding preparation section that supplies a fluid containing water to the plasma-treated surfaces to be bonded to form hydroxyl groups on the surfaces to be bonded, and the bonding section forms the bonded substrate by contacting the two substrates with their surfaces to be bonded facing each other. [Effects of the Invention]

[0021] In a method and apparatus for manufacturing a bonded substrate according to one aspect of the present invention, ultrasonic testing is performed using an ultrasonic testing unit having a supply nozzle that supplies a medium for transmitting ultrasonic waves between an ultrasonic sensor and the bonded substrate. In this case, ultrasonic testing can be performed while supplying the medium from the supply nozzle to areas required for testing, without supplying the medium to areas not required for testing. Therefore, it is not necessary to submerge the entire bonded substrate in the medium, and the medium does not need to come into contact with the bonding interface, so ultrasonic testing can be performed without deteriorating the bonding condition of the bonded substrate.

[0022] Furthermore, because ultrasonic testing can be performed before the bond between the bonded substrates is strengthened, any bond defects can be detected before the bond is strengthened. Before the bond is strengthened, the bonded substrates can be separated relatively easily, and the resulting substrates can be used to manufacture new bonded substrates. This improves the manufacturing efficiency of bonded substrates.

[0023] Therefore, according to one aspect of the present invention, there is provided a method for manufacturing a bonded substrate and a bonding apparatus that can efficiently manufacture bonded substrates by ultrasonically inspecting the bonding state of the bonded substrates without deteriorating the bonding state. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1(A) is a perspective view that schematically shows how two substrates are bonded together, and FIG. 1(B) is a perspective view that schematically shows the bonded substrates. [Figure 2] FIG. 2 is a plan view schematically showing the configuration of the joining device. [Figure 3] FIG. 2 is a partial cross-sectional front view showing a plasma processing unit included in the bonding apparatus. [Figure 4] FIG. 2 is a cross-sectional view schematically showing a joining preparation unit provided in the joining device. [Figure 5] FIG. 2 is a cross-sectional view schematically showing a joining section provided in the joining device. [Figure 6] 1 is a cross-sectional view schematically showing an inspection unit (ultrasonic inspection unit) provided in a bonding device. [Figure 7] FIG. 7(A) is a cross-sectional view that schematically shows an inspection section (ultrasound inspection section) according to a modified example, and FIG. 7(B) is a cross-sectional view that schematically shows a manner in which the inspection section according to the modified example is used. [Figure 8] 10 is a perspective view schematically illustrating a state in which a bonded substrate is carried into a bonding strengthening section included in the bonding device. FIG. [Figure 9] 1 is a flowchart showing the flow of each step of a method for manufacturing a bonded substrate. DETAILED DESCRIPTION OF THE INVENTION

[0025] An embodiment of the present invention will be described with reference to the accompanying drawings. In a bonding apparatus and a method for manufacturing a bonded substrate according to this embodiment, two substrates are bonded together to form a bonded substrate. FIG. 1(A) is a perspective view that schematically shows how two substrates are brought into contact with each other, and FIG. 1(B) is a perspective view that schematically shows the bonded substrate. First, the substrates that are the constituent materials of the bonded substrate will be described.

[0026] 1(A) schematically shows two substrates (a first substrate 11 and a second substrate 13). The substrates 11 and 13 are, for example, wafers formed into a disk shape from a semiconductor material such as silicon (Si). A plurality of mutually intersecting division lines (not shown) are set on the front surfaces (bonding surfaces) 11a and 13a or the back surfaces 11b and 13b of the substrates 11 and 13, and devices (not shown) are formed in each region defined by the division lines.

[0027] Each of the multiple devices includes, for example, an element for constituting an IC, a semiconductor memory, or an image sensor. By bonding substrates 11 and 13 so that their planned dividing lines overlap, and then cutting bonded substrate 15 along the planned dividing lines, device chips each equipped with a device can be manufactured.

[0028] There are no limitations on the material, shape, structure, size, etc. of the substrates 11 and 13. The substrates 11 and 13 may be made of, for example, a semiconductor material other than silicon (e.g., silicon carbide (SiC) or gallium nitride (GaN)). Similarly, there are no limitations on the type, number, shape, structure, size, or arrangement of devices. Furthermore, the substrates 11 and 13 do not have to have devices formed thereon. Furthermore, the substrates 11 and 13 do not have to be disk-shaped wafers, and may be rectangular plates.

[0029] Furthermore, the first substrate 11 and the second substrate 13 do not have to be the same type of substrate. One of the first substrate 11 and the second substrate 13 may have a device and the other may not. One of the first substrate 11 and the second substrate 13 may function as a support substrate for the other.

[0030] An insulating film may be provided on one or both of the front surface 11a, 13a and the back surface 11b, 13b of the substrates 11, 13. The insulating film may be made of, for example, a silicon oxide film (SiO film), a silicon nitride film (SiN film), a silicon oxynitride film (SiON film), a nitrogen-added silicon carbide film (SiCN film), or an organic resin film.

[0031] Furthermore, in the substrates 11 and 13, the front surfaces 11a and 13a and the back surfaces 11b and 13b opposite to the front surfaces 11a and 13a are parallel to each other, and local variations in thickness are extremely small. For example, if a device is provided on the substrates 11 and 13, the insulating film covers the device. The upper surface of the insulating film may be planarized by a method such as CMP (Chemical Mechanical Polishing).

[0032] In the method for manufacturing a bonded substrate according to this embodiment, there are cases where a material such as an adhesive is not used to bond first substrate 11 and second substrate 13. As will be described in detail later, the bonding state of bonded substrate 15 formed by bonding two substrates 11, 13 is inspected.

[0033] Ultrasonic testing is suitable for inspecting the bonding condition. However, when performing ultrasonic testing, it is necessary to supply a medium (liquid) such as pure water, which acts as a transmission medium for ultrasonic waves, between the inspection device (inspection unit, ultrasonic sensor) and the bonded substrate 15. For example, conventional ultrasonic testing is performed by submerging the bonded substrate 15 in water.

[0034] When manufacturing the bonded substrate 15, a bonding process for bonding the two substrates 11, 13 and a bond strengthening process for strengthening the bond of the bonded substrate 15 are performed. If a conventional ultrasonic inspection is performed before the bond strengthening process, water (medium) will get between the two substrates 11, 13 (at the bonding interface), deteriorating the bonded state. Therefore, in the bonding apparatus and bonded substrate manufacturing method according to this embodiment, the ultrasonic inspection is performed so that water (medium) does not come into contact with the two substrates 11, 13.

[0035] The method for manufacturing the bonded substrate is carried out, for example, by a bonding apparatus. As described below, the bonding apparatus brings two substrates 11 and 13 into contact with each other to bond them, and then ultrasonically inspects the bonded substrate 15. Next, the bonding apparatus will be described. Note that the bonding apparatus described below is a bonding apparatus that bonds the substrates 11 and 13 by plasma processing, but the bonding apparatus is not limited to this. The substrates 11 and 13 may also be bonded at room temperature without plasma processing. Also, an adhesive may be used to bond the substrates 11 and 13.

[0036] First, an overview of the bonding apparatus 2 will be described. Fig. 2 is a plan view that schematically shows the configuration of the bonding apparatus 2. In Fig. 2, each unit included in the bonding apparatus 2 is shown as a block. Each unit included in the bonding apparatus 2 is supported by a rectangular parallelepiped apparatus base 4. The bonding apparatus 2 includes, on the apparatus base 4, a bonding unit 14 that bonds two substrates 11, 13 together, and an inspection unit 16 that inspects the bonded substrate 15 bonded by the bonding unit 14.

[0037] More specifically, the bonding apparatus 2 has a plasma processing unit 10, a bonding preparation unit 12, and a bonding unit 14 as components contributing to bonding. The plasma processing unit 10 plasma-treats one or both of the surfaces to be bonded (surfaces 11a, 13a) of the two substrates 11, 13. The bonding preparation unit 12 supplies a water-containing fluid to the plasma-treated surfaces to be bonded (surfaces 11a, 13a) to form hydroxyl groups on the surfaces to be bonded. The bonding unit 14 then contacts the two substrates 11, 13 with their surfaces to be bonded (surfaces 11a, 13a) facing each other to form a bonded substrate 15.

[0038] Furthermore, the inspection unit 16 has an ultrasonic inspection unit that applies ultrasonic waves to the bonded substrate 15 to obtain information about the bonded state of the bonded substrate 15. If the ultrasonic inspection by the ultrasonic inspection unit of the inspection unit 16 confirms that there is no problem with the bonded state of the bonded substrate 15, a process for strengthening the bond strength is carried out on the bonded substrate 15. The bonding device 2 is provided with a bond strengthening unit 18 that carries out the bond strengthening process.

[0039] Furthermore, bonding apparatus 2 is provided with transport paths 20a, 20b, 20c, 20d, 20e, and 20f that connect each part. Substrates 11 and 13 to be bonded by bonding apparatus 2 and the formed bonded substrate 15 are transported through these transport paths 20a, 20b, 20c, 20d, 20e, and 20f.

[0040] Cassette mounting tables 6 and 8 are provided on the outer periphery of the apparatus base 4. Cassettes (not shown) containing multiple substrates 11 and 13 are placed on the cassette mounting tables 6 and 8. The cassette mounting tables 6 and 8 can be raised and lowered by an elevator (not shown). The elevator adjusts the height of the cassette mounting tables 6 and 8, thereby adjusting the height of the substrates 11 and 13 being carried in and out of the bonding apparatus 2 by the transport mechanism.

[0041] The bonding apparatus 2 also has a plurality of internal transport mechanisms for transporting the substrates 11 and 13. The substrates 11 and 13 may be transported manually by an operator. In this case, the transport mechanisms for transporting the substrates 11 and 13 can be omitted.

[0042] The bonding apparatus 2 includes a controller (control unit) 22 that controls each of the components. The plasma processing section 10, the bonding preparation section 12, the bonding section 14, the inspection section 16, the bonding strengthening section 18, the cassette mounting tables 6 and 8, the transport mechanism, etc. are controlled by the controller 22.

[0043] The controller 22 is configured by a computer including, for example, a processor represented by a CPU (Central Processing Unit) and a memory. The memory includes a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a flash memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive).

[0044] The auxiliary storage device stores software including a predetermined program. The functions of the controller 22 are realized by operating a processor or the like in accordance with this program. Further details of the configuration, functions, etc. of the controller 22 will be described later.

[0045] 2 includes a plasma processing unit 10, a bonding preparation unit 12, a bonding unit 14, an inspection unit 16, a bonding strengthening unit 18, cassette mounting tables 6 and 8, a controller 22, and the like. However, the bonding apparatus 2 does not need to include all of these components, and some of the components may be omitted. Furthermore, one of these components may also serve the function of another component. Next, each component of the bonding apparatus 2 will be described in detail.

[0046] 3 is a partial cross-sectional front view showing the plasma processing unit 10. The plasma processing unit 10 includes a chamber (processing chamber) 26 in which the substrates 11 and 13 are accommodated. The chamber 26 is made of a conductive material such as metal and is grounded. The interior of the chamber 26 corresponds to a processing space 28 in which the plasma processing of the substrates 11 and 13 is carried out.

[0047] An opening 26a for transporting the substrates 11 and 13 is provided in the side wall of the chamber 26. A gate (opening / closing door) 30 for opening and closing the opening 26a is provided outside the opening 26a. A moving mechanism (not shown) such as an air cylinder is connected to the gate 30, and the moving mechanism raises and lowers the gate 30 along the side wall of the chamber 26.

[0048] By lowering the gate 30 to expose the opening 26a, the substrates 11 and 13 can be loaded into or unloaded from the processing space 28 through the opening 26a. In addition, by raising the gate 30 to close the opening 26a, the processing space 28 is sealed.

[0049] An opening 26b that connects the inside and outside of the chamber 26 is provided in the bottom wall of the chamber 26. The opening 26b is connected to an exhaust device 34 such as a vacuum pump via piping 32. When the exhaust device 34 is operated with the processing space 28 sealed, the processing space 28 is evacuated and reduced in pressure.

[0050] A holding table (chuck table) 36 for holding the substrates 11 and 13 is provided in the processing space 28. The upper surface of the holding table 36 is a flat surface that is approximately parallel to the horizontal plane and forms a holding surface 36a for holding the substrates 11 and 13.

[0051] The holding table 36 may be an electrostatic chuck that holds the substrates 11, 13 by electrical force. For example, the holding table 36 is made of a dielectric material such as ceramics, and a disk-shaped electrode 38 is provided inside the holding table 36. The electrode 38 is disposed generally parallel to the holding surface 36a and is connected to a high-frequency power supply 42 via a matching box 40. A cooling path (not shown) through which a coolant such as water flows may be provided inside the holding table 36. The holding table 36 is cooled by flowing the coolant through the cooling path.

[0052] A gas ejection head 44 is provided above the holding table 36. The gas ejection head 44 is made of a conductive material such as metal, and is inserted into an opening 26c provided in the upper wall of the chamber 26. An annular bearing 46 made of an insulating material is provided between the chamber 26 and the gas ejection head 44. The bearing 46 is provided so as to surround the gas ejection head 44, and insulates the chamber 26 from the gas ejection head 44.

[0053] The gas ejection head 44 is connected to a high-frequency power supply 50 via a matching box 48. An elevator mechanism (not shown) that raises and lowers the gas ejection head 44 in the vertical direction is connected to the gas ejection head 44. The distance between the holding table 36 and the gas ejection head 44 is adjusted by raising and lowering the gas ejection head 44 with the elevator mechanism.

[0054] A gas diffusion space 44a to which plasma processing gas is supplied is provided inside the gas ejection head 44. A plurality of gas supply paths 44b that connect the processing space 28 of the chamber 26 to the gas diffusion space 44a are provided on the lower surface of the gas ejection head 44. A pair of gas supply paths 44c and 44d are provided on the upper surface of the gas ejection head 44. The gas supply path 44c is connected to a gas supply source 54a via a pipe 52a, and the gas supply path 44d is connected to a gas supply source 54b via a pipe 52b.

[0055] The gas supply source 54a supplies a gas for plasma processing to the gas diffusion space 44a via the pipe 52a and the gas supply path 44c. Similarly, the gas supply source 54b supplies a gas for plasma processing to the gas diffusion space 44a via the pipe 52b and the gas supply path 44d. This causes the two gases to be mixed in the gas diffusion space 44a. Note that while FIG. 3 illustrates a configuration in which gas is supplied to the gas ejection head 44 from two gas supply sources 54a and 54b, the number of gas supply sources connected to the gas ejection head 44 may be one or three or more.

[0056] When plasma processing is performed on substrates 11 and 13 using plasma processing unit 10, gate 30 first descends to expose opening 26a. Then, substrates 11 and 13 are loaded into processing space 28 through opening 26a by a transport mechanism (not shown) and placed on holding surface 36a of holding table 36. Note that when loading substrates 11 and 13, it is preferable to raise gas ejection head 44 and widen the gap between holding table 36 and gas ejection head 44.

[0057] Next, the gate 30 is raised to close the opening 26a, sealing the processing space 28. Then, a predetermined voltage is applied to the electrode 38 by the high-frequency power supply 42. This generates dielectric polarization on the holding surface 36a side of the holding table 36, and an electrostatic attraction force acts between the holding surface 36a and the substrates 11 and 13. As a result, the substrates 11 and 13 are attracted and held by the holding surface 36a.

[0058] The height of the gas ejection head 44 is adjusted so that the holding table 36 and the gas ejection head 44 are spaced apart at a distance suitable for plasma processing. The exhaust device 34 is then activated to reduce the pressure in the processing space 28.

[0059] Next, gas for plasma processing is supplied from gas supply source 54a and / or gas supply source 54b to gas diffusion space 44a. Furthermore, high-frequency power is applied to gas ejection head 44 by high-frequency power supply 50. As a result, the gas in gas diffusion space 44a is converted into plasma, and the plasma-state gas is supplied and dispersed into processing space 28 via multiple gas supply paths 44b. This allows the plasma-state gas to be supplied to substrates 11 and 13 on holding table 36, and a predetermined plasma processing is performed on substrates 11 and 13.

[0060] 4 is a cross-sectional view schematically showing the bonding preparation unit 12. The bonding preparation unit 12 includes a holding table 56 that holds the substrates 11 and 13, and a water supply unit 82 that supplies water to the substrates 11 and 13 held by the holding table 56. When water (a fluid containing water) is supplied to the outer surfaces of the substrates 11 and 13 whose outer surfaces have been plasma-treated, hydroxyl groups (-OH) can be formed on the outer surfaces of the substrates 11 and 13. Next, each component of the bonding preparation unit 12 will be described in detail.

[0061] FIG. 4 includes a cross-sectional view that schematically shows the holding table 56. The holding table 56 has a disk-shaped frame 58 made of metal. A disk-shaped recess is formed on the upper surface of the frame 58. A disk-shaped porous plate 60 having approximately the same diameter as the recess is fixed to this recess. The porous plate 60 is made of, for example, porous ceramics. The upper surface of the porous plate 60 functions as a holding surface 56a that holds the substrates 11 and 13 by suction.

[0062] A spindle 62 extending in a direction intersecting the holding surface 56a is connected to the underside of the holding table 56. The lower end of the spindle 62 is connected to a rotary drive source 66 formed of a motor or the like, and an encoder 68 is attached to the rotary drive source 66. When the rotary drive source 66 is operated to rotate the spindle 62, the holding table 56 rotates around an axis intersecting the holding surface 56a. At this time, the operating status of the rotary drive source 66 is monitored and controlled by the encoder 68.

[0063] A suction passage 70 is formed inside the frame 58, one end of which communicates with the porous plate 60 and the other end of which is exposed on the outer surface of the frame 58. A suction path provided in the spindle 62 is connected to this suction passage 70, which is connected to a suction source 72 and an air supply source 74 via a rotary joint 64 attached to the spindle 62.

[0064] More specifically, a suction source 72 such as a vacuum pump is connected to the suction path 70 via a gate valve 76a and an adjustment valve 78a. The air pressure between the suction source 72 and the suction path 70 is monitored by a pressure gauge 80. When the suction source 72 is activated, the gate valve 76a is opened, and a negative pressure adjusted to a predetermined level by the adjustment valve 78a is applied to the holding surface 56a through the suction path 70, the substrates 11 and 13 placed on the holding surface 56a are held by suction on the holding table 56.

[0065] An air supply source 74, such as a cylinder or a pump, is connected to the suction path 70 via a gate valve 76b and an adjustment valve 78b. The air pressure between the air supply source 74 and the suction path 70 is monitored by a pressure gauge 80. When the air supply source 74 is activated, the gate valve 76b is opened, and air adjusted to a predetermined pressure by the adjustment valve 78b is applied to the holding surface 56a through the suction path 70, the air causes the substrates 11 and 13 placed on the holding surface 56a to float up. This makes it easy to carry the substrates 11 and 13 out of the holding table 56.

[0066] The water supply unit 82 of the joining preparation section 12 includes a rotating shaft 86 erected outside the holding table 56, an arm 88 extending horizontally from the upper end of the rotating shaft 86, and a nozzle 90 provided at the tip of the arm 88. A rotational drive source 84 such as a motor is connected to the lower end of the rotating shaft 86. An encoder 94 is attached to the rotational drive source 84, which monitors and controls the operation of the rotational drive source 84. A water supply source 96 and an air supply source 98 are connected to the nozzle 90 via piping such as a tube.

[0067] When the rotary drive source 84 is operated, the rotary shaft 86 rotates in the direction of extension, and the nozzle 90 moves with the radius of the arm 88. The length of the arm 88 is determined so that the moving nozzle 90 can pass above the center of the holding surface 56a of the holding table 56.

[0068] In the bonding preparation section 12, the substrates 11 and 13, the outer surfaces of which have been plasma-treated, are carried onto the holding table 56. At this time, the holding table 56 holds the substrates 11 and 13 by suction. As a result, the surfaces 11a and 13a of the substrates 11 and 13, which will be the surfaces to be bonded, are exposed upward. Next, the rotary drive source 66 is actuated to start rotating the holding table 56, and the rotary drive source 84 is actuated to reciprocate the nozzle 90 above the holding table 56.

[0069] In this state, when the water supply source 96 and the air supply source 98 are operated, pressurized water 92 is sprayed from the nozzle 90 toward the substrates 11, 13 held on the holding table 56. When the water comes into contact with the plasma-treated substrates 11, 13, hydroxy groups are arranged on the surfaces (bonding surfaces) 11a, 13a of the substrates 11, 13.

[0070] 5 is a cross-sectional view schematically showing the bonding portion 14. In the bonding portion 14, the bonding surfaces of the substrates 11 and 13, which have been plasma-treated and have hydroxy groups disposed on their bonding surfaces (surfaces 11a and 13a), are brought into contact with each other, and the substrates 11 and 13 are bonded together.

[0071] The bonding section 14 bonds the substrates 11, 13 inside a bonding chamber 100 to prevent particles such as dust from entering between the substrates 11, 13 to be bonded. The bonding chamber 100 is a space shielded from the external atmosphere. Inside the bonding chamber 100, there are provided a first holding unit 102 that supports one of the two substrates 11, 13 from below, and a second holding unit 104 that supports the other of the two substrates 11, 13 from above above the first holding unit 102.

[0072] The first holding unit 102 and the second holding unit 104 are, for example, chuck tables configured similarly to the holding table 56 of the bonding preparation section 12. The upper surface of the first holding unit 102 serves as a holding surface 102a that applies negative pressure to the substrates 11 and 13. The lower surface of the second holding unit 104 serves as a holding surface 104a that applies negative pressure to the substrates 11 and 13.

[0073] The second holding unit 104 is also capable of moving up and down. A lifting shaft 108 constituting a ball screw or air cylinder type lifting mechanism (not shown) is connected to the upper end of the second holding unit 104. Note that the lifting mechanism is not limited to the ball screw type or air cylinder type. A shrinkable cover 106 is provided at the upper end of the bonding chamber 100 to keep the bonding chamber 100 isolated from the external atmosphere while responding to the lifting shaft 108 moving up and down. For example, when the lifting shaft 108 moves down, the shrinkable cover 106 shrinks, and when the lifting shaft 108 moves up, the shrinkable cover 106 extends.

[0074] When bonding two substrates 11, 13 in bonding section 14, first, the two substrates 11, 13 are carried into bonding chamber 100. Then, one of substrates 11, 13 is placed on holding surface 102a of first holding unit 102. Thereafter, the suction source of first holding unit 102 is activated, and this one of substrates 11, 13 is held by suction in first holding unit 102. In FIG. 5, second substrate 13 is placed on holding surface 102a of first holding unit 102 and is held by suction in first holding unit 102.

[0075] Furthermore, the other of the two substrates 11, 13 is transported by a transport unit (not shown) and brought into contact with the holding surface 104a of the second holding unit 104. Next, the other of the two substrates 11, 13 is suction-held by the second holding unit 104. Thereafter, the transport unit is retracted from the bonding chamber 100. At this time, the other of the substrates 11, 13 does not fall because it is being suction-held by the second holding unit 104. In FIG. 5, the first substrate 11 is being suction-held by the second holding unit 104.

[0076] When the first holding unit 102 and the second holding unit 104 respectively hold the substrates 11 and 13 by suction, the substrates 11 and 13 are aligned with high precision to predetermined positions so that the two substrates 11 and 13 overlap with high precision along the movement direction of the lifting shaft 108. In addition, the orientations of the two substrates 11 and 13 are determined so that the surfaces to be bonded (surfaces 11a and 13a) of the two substrates 11 and 13 face each other.

[0077] Next, in the bonding section 14, the first holding unit 102 and the second holding unit 104 are brought relatively close to each other so that the surfaces to be bonded (surfaces 11a, 13a) of the two substrates 11, 13 come into contact with each other. For example, the lifting shaft 108 is lowered to bring the second holding unit 104 closer to the first holding unit 102. Alternatively, the first holding unit 102 may be provided with a lifting mechanism, and the first holding unit 102 may be lifted toward the second holding unit 104.

[0078] When the surfaces to be bonded (surfaces 11a, 13a) of the two substrates 11, 13 come into contact with each other, hydrogen bonds are formed between the two surfaces via hydroxy groups arranged on the surfaces by the plasma processing unit 10. This bonds the substrates 11, 13 to form a bonded substrate 15 (see FIG. 1(B)). However, at this stage, the bond strength of the bonded substrate 15 is relatively low. Therefore, as described below, a step of strengthening the bond of the bonded substrate 15 is carried out.

[0079] The inspection unit 16 included in the bonding device 2 inspects the bonding state of the bonded substrate 15. In particular, the inspection unit 16 performs an ultrasonic inspection of the bonded substrate 15. Although ultrasonic inspection generally requires a relatively long time, it can detect minute void defects (bonding defects) of about several tens to 100 μm.

[0080] The inspection unit 16 is mainly composed of an ultrasonic inspection unit that performs ultrasonic inspection of the bonded substrate 15. Fig. 6 is a cross-sectional view that schematically shows the inspection unit (ultrasonic inspection unit) 16 provided in the bonding apparatus 2. The ultrasonic inspection unit provided in the inspection unit 16 includes a holder 110 that holds the bonded substrate 15, an ultrasonic sensor 118 that includes an ultrasonic oscillator 120 and an ultrasonic receiver 122, and a supply nozzle 126 that supplies a medium between the ultrasonic sensor 118 and the bonded substrate 15.

[0081] The holding unit 110 of the ultrasonic inspection unit (inspection unit 16) is mainly composed of an annular holding frame 112 having a through-hole 114 with a diameter smaller than that of the bonded substrate 15. The upper surface of the holding frame 112 is flat, and the bonded substrate 15 is placed on this upper surface so as to close the through-hole 114. The holding unit 110 may also include a clamping mechanism (not shown) for fixing the bonded substrate 15 placed on the holding frame 112.

[0082] The ultrasonic inspection section (inspection section 16) includes an inspection unit 116 that performs ultrasonic inspection of the bonded substrate 15 held by the holder 110. The inspection unit 116 is configured, for example, with a tray section 124, an ultrasonic sensor 118 supported by the tray section 124, and a supply nozzle 126 that surrounds the ultrasonic sensor 118 above the tray section 124.

[0083] Cylindrical supply nozzle 126 has openings at the top and bottom, with the bottom opening being closed by tray portion 124 and the top opening being open. A pipe-like medium supply path 132 is provided on the side of supply nozzle 126, which serves as a path for supplying water or the like, which serves as an ultrasonic wave transmission medium, into supply nozzle 126. A medium supply source 134 is connected to medium supply path 132 via a tube or the like.

[0084] A liquid such as water (pure water), methanol, ethanol, or acetone is supplied as a medium for transmitting ultrasonic waves from medium supply source 134 through medium supply path 132 into the internal space of supply nozzle 126. When the medium is supplied into the internal space of supply nozzle 126, the internal space is filled with the medium. As a result, ultrasonic sensor 118 located inside supply nozzle 126 is submerged in the medium.

[0085] When the entire internal space is filled with medium and more medium is supplied to this internal space, the medium overflows from the opening at the top of the supply nozzle 126. The overflowing medium is received by the tray portion 124. The tray portion 124 has an outer peripheral wall 130 provided on the outer periphery to prevent the received medium from leaking out. The medium overflowing from the supply nozzle 126 accumulates in the area surrounded by the outer peripheral wall 130 of the tray portion 124.

[0086] A medium recovery path 138, which serves as a path for discharging the medium, is provided on the bottom wall of the tray section 124, and the medium recovery path 138 is connected to the medium recovery tank 136 via a tube or the like. The medium accumulated in the tray section 124 is recovered into the medium recovery tank 136 via the medium recovery path 138.

[0087] The inspection unit 116 is connected to a driving unit (not shown) such as a ball screw type or air cylinder type, and is movable in a direction along the penetration direction of the through-hole 114 of the holding frame 112 of the holding unit 110 and in a direction along the upper surface of the holding frame 112. Alternatively, the driving unit may be connected to the holding unit 110, and the holding unit 110 may be movable. Alternatively, both the inspection unit 116 and the holding unit 110 may be movable.

[0088] When ultrasonic testing is performed on the bonded substrate 15 held by the holder 110, the testing unit 116 is brought close to the lower surface of the bonded substrate 15 (the back surface 13b of the second substrate 13) from below. The medium is continuously supplied into the internal space of the supply nozzle 126, filling this internal space with the medium, and the space between the bonded substrate 15 and the ultrasonic testing unit (ultrasonic sensor 118) with the medium. This forms a transmission path for ultrasonic waves. At this time, the medium overflowing from the supply nozzle 126 is collected in the tray unit 124.

[0089] The ultrasonic wave oscillator 120 and ultrasonic wave receiver 122 of the ultrasonic sensor 118 are made of piezoelectric ceramics or the like. The ultrasonic wave oscillator 120 generates ultrasonic waves and sends them to the bonded substrate 15 through a medium filled in a supply nozzle 126. The ultrasonic waves are reflected by the bonded interface 17 of the bonded substrate 15 (see FIG. 7(A) and the like) and travel through the medium toward the ultrasonic wave receiver 122.

[0090] The ultrasonic wave receiving unit 122 receives the ultrasonic waves reflected at the bonding interface 17 and generates an electric signal that reflects the vibration characteristics of the ultrasonic waves. For example, the generated electric signal is transmitted to a controller 22 (see FIG. 2) included in the bonding device 2.

[0091] The vibration characteristics of the ultrasonic waves that reach the bonded interface 17 and are reflected at the bonded interface 17 reflect the bonded state of the two substrates 11, 13 at the bonded interface 17. For example, the vibration characteristics of the reflected ultrasonic waves differ depending on whether or not there are bond defects (voids) or poor bonding at the bonded interface 17 in the area reached by the ultrasonic waves. Therefore, by receiving the reflected ultrasonic waves with the ultrasonic wave receiver 122 and obtaining the vibration characteristics of the ultrasonic waves, information regarding the bonded state at the bonded interface 17 can be obtained.

[0092] As described above, the ultrasonic inspection section of the inspection unit 16 supplies a medium from the supply nozzle 126 to the underside of the bonded substrate 15 (the back surface 13b of the second substrate 13), and transmits ultrasonic waves from the ultrasonic oscillator 120 to the bonded substrate 15 via the medium supplied to the underside of the bonded substrate 15. Then, the ultrasonic receiver 122 receives the ultrasonic waves returning from the bonded substrate 15, thereby enabling ultrasonic inspection.

[0093] In this way, the bonding apparatus 2 according to this embodiment performs ultrasonic inspection of the bonded substrate 15 by locally supplying a medium, such as water, that transmits ultrasonic waves to the underside of the bonded substrate 15. Therefore, there is no need to submerge the bonded substrate 15 in the medium, and the medium does not reach the bonded interface 17 exposed on the side of the bonded substrate 15. In other words, ultrasonic inspection can be performed on the bonded substrate 15 before the bond strengthening step is performed, and the quality of the bonded state can be confirmed. At this time, the bonded state of the bonded substrate 15 does not deteriorate.

[0094] For example, if the bonding state of bonded substrate 15 is inspected before the bond strengthening step is performed and it is found as a result that the bonding state does not meet a predetermined standard, bonded substrate 15 can be separated (peel) back into two substrates 11, 13. If it is found that the bonding state does not meet the predetermined standard after the bond strengthening step is performed, it is difficult to separate bonded substrate 15 without damaging substrates 11, 13. Substrates 11, 13 that have been separated before the bond strengthening step can be used to re-form bonded substrate 15.

[0095] In the bonding device 2 according to this embodiment, the inspection unit 16 may be further configured to make it even more difficult for the medium used in the ultrasonic inspection to reach the bonding interface 17 of the bonded substrates 15. Fig. 7(A) is a cross-sectional view schematically showing an inspection unit (ultrasonic inspection unit) 16a according to a modified example, and Fig. 7(B) is a cross-sectional view schematically showing a usage mode of the inspection unit 16a according to the modified example.

[0096] 7(A) and 7(B), the inspection unit 116 of the inspection section 16a is omitted, but the inspection section 16a according to the modified example also includes the inspection unit 116 similar to the above-described inspection section 16. Therefore, a description of the configuration and usage of the inspection unit 116 will be omitted.

[0097] The inspection unit (ultrasonic inspection unit) 16a according to the modified example includes a holding unit 140. The holding unit 140 is mainly composed of an annular holding frame 142 having a through-hole 144 with a diameter smaller than that of the bonded substrate 15. The upper surface of the holding frame 142 is flat, and the bonded substrate 15 is placed on this upper surface so as to close the through-hole 144.

[0098] Furthermore, the holding frame 142 is provided with a holding mechanism, which will be described below, for fixing the bonded substrate 15 placed on the holding frame 142. The holding unit 140 includes, as the holding mechanism, a tube 148 arranged in an annular shape on the holding frame 142, and an annular housing portion 146 provided on the holding frame 142 for housing the tube 148.

[0099] The inner diameter of the tube 148 (the diameter of the inner peripheral surface of the annular tube 148) is set to be larger than the outer diameter of the bonded substrate 15. The annular housing portion 146 does not open to the outer peripheral surface of the holding frame 142, and when the tube 148 is housed in the annular housing portion 146, the tube 148 is exposed toward the center of the holding portion 140. When the bonded substrate 15 is placed on the holding frame 142, the tube 148 surrounds the bonded substrate 15.

[0100] Furthermore, tube 148 can expand and contract depending on the pressure (internal pressure) in internal space 150. A pressure supply source such as a pump that controls the internal pressure is connected to tube 148, and tube 148 can be deformed by operating the pressure supply source to change the internal pressure. For example, tube 148 deforms so that its inner diameter becomes smaller as the internal pressure increases, and so that its inner diameter becomes larger as the internal pressure decreases. Alternatively, tube 148 deforms so that its inner diameter becomes larger as the internal pressure increases, and so that its inner diameter becomes smaller as the internal pressure decreases.

[0101] When bonded substrate 15 is placed on holding frame 142, tube 148 is deformed by pressure supplied from the pressure supply source, thereby sealing bonded interface 17 exposed on the outer periphery of bonded substrate 15 in holding part 140. In other words, tube 148 seals bonded interface 17 from the outer periphery, preventing bonded interface 17 from being exposed to the outside.

[0102] Note that the tube 148 may be deformed by a method that does not depend on a change in internal pressure. For example, the tube 148 may be deformed by having a portion of the tube 148 pulled outward. When a portion of the tube 148 is pulled, the diameter of the remaining portion of the tube 148 becomes smaller. This may seal the bonding interface 17 of the bonded substrates 15. Alternatively, the tube 148 may be pressed radially inward from the radially outer side over the entire circumference to seal the bonding interface 17. In either case, the bonding interface 17 is sealed by the holding portion 140.

[0103] In this state, if an ultrasonic inspection of bonded substrate 15 is performed by the ultrasonic inspection section (inspection unit 116) while supplying a medium such as water between ultrasonic sensor 118 and bonded substrate 15, even if the medium scatters in an unexpected location, it will not reach bonded interface 17. In other words, tube 148 prevents the medium such as water from entering bonded interface 17.

[0104] Bonded substrate 15 may be fixed to holding unit 140 by tube 148 when tube 148 is deformed to seal bonded interface 17. Furthermore, holding unit 140 may have a fixing device such as a clamp mechanism in addition to tube 148, and bonded substrate 15 may be fixed by the fixing device regardless of whether tube 148 seals bonded interface 17 or not.

[0105] Furthermore, if the holding unit 140 can seal the bonded interface 17 with the tube 148, the inspection unit 16a does not need to use the inspection unit 116 for ultrasonic inspection, which locally supplies a medium between the ultrasonic sensor 118 and the bonded substrate 15 as described in Fig. 6. For example, if the bonded interface 17 is sealed with the tube 148, the ultrasonic inspection may be performed by submerging the bonded substrate 15 in a medium.

[0106] The bonding apparatus 2 according to this embodiment performs an ultrasonic inspection of the bonded substrate 15 using the inspection units 16, 16a described above, and determines whether the bonded state of the bonded substrate 15 is good or bad. For example, the controller 22 (see FIG. 2) of the bonding apparatus 2 includes a determination unit 24 that determines whether the bonded state of the bonded substrate 15 is good or bad based on the inspection results of the ultrasonic inspection.

[0107] For example, the determination unit 24 receives an electrical signal reflecting information related to the bonding state of the bonded substrate 15 from the inspection units 16, 16a. Furthermore, for example, determination conditions for determining whether the bonding state is good are stored in the memory unit of the controller 22. The determination unit 24 determines that the bonding state of the bonded substrate 15 is good if the bonding state of the bonded substrate 15 satisfies the determination conditions, and determines that the bonding state of the bonded substrate 15 is poor if the bonding state of the bonded substrate 15 does not satisfy the determination conditions.

[0108] More specifically, for example, the storage unit of the controller 22 stores, as a judgment condition, that no bonding defects are detected at the bonded interface 17. The judgment unit 24 judges the bonded state to be good when no bonding defects are detected from the inspection result of the bonded state by ultrasonic testing. On the other hand, the judgment unit 24 judges the bonded state to be poor when any bonding defects are detected.

[0109] If the determining unit 24 determines that the bonded state is good, the bonding device 2 performs a bond strengthening process on the bonded substrate 15 in the bond strengthening unit 18, which will be described next. On the other hand, if the determining unit 24 determines that the bonded state is poor, the bonded substrate 15 is not subjected to the bond strengthening process, and the bonded substrate 15 is conveyed to a cassette by passing through the bond strengthening unit 18. In this case, by separating the bonded substrate 15 into the two substrates 11 and 13, the substrates 11 and 13 can be reused.

[0110] 8 is a perspective view schematically showing how the bonded substrate 15 is carried into the bond strengthening section 18 included in the bonding device 2. The bond strengthening section 18 will be described. The bond strengthening section 18 is configured by, for example, a heating and holding table 152 with a built-in heater.

[0111] The heating and holding table 152 has a porous member exposed on its upper surface and having a diameter equal to that of the bonded substrate 15, and has a suction path formed therein, one end of which leads to the porous member and the other end of which leads to a suction source (not shown). The upper surface of the porous member serves as a holding surface 154 on which the bonded substrate 15 to be suction-held is placed. A heater (not shown) made of an electric heating wire or the like is also provided inside the heating and holding table 152.

[0112] 8, the bonded substrate 15 is placed on the holding surface 154 of the heating and holding table 152, and the suction source is activated to hold the bonded substrate 15 by suction on the heating and holding table 152. Next, the heater is activated to transfer heat to the bonded substrate 15, heating the bonded substrate 15 to a predetermined temperature.

[0113] When one or both of the two substrates 11, 13 are plasma-treated to form a bonded substrate 15 through hydrogen bonding, the adhesion between the two substrates 11, 13 improves when the bonded substrate 15 is heated to a certain temperature. This is thought to be due in part to the fact that a dehydration condensation reaction occurs involving the hydroxy groups that constitute the hydrogen bonds, forming a covalent bond via oxygen atoms between the surface (bonded surface) 11a of the first substrate 11 and the surface (bonded surface) 13a of the second substrate 13. This bond is stronger than a hydrogen bond.

[0114] The bonded substrates 15 whose bonding state has been strengthened in the bond strengthening section 18 are placed in a cassette placed on the cassette mounting table 8 and carried out from the bonding apparatus 2. Note that for bonded substrates 15 whose bonding state is determined to be poor by the determining section 24 of the controller 22, no heat treatment or the like for strengthening the bond is performed in the bond strengthening section 18. In this case, the bonded substrates 15 are placed in a cassette without being subjected to heat treatment or the like in the bond strengthening section 18.

[0115] As described above, in the bonding apparatus 2 according to this embodiment, ultrasonic testing can be performed while supplying a medium such as water from a supply nozzle to an area required for the testing, without supplying the medium to areas not targeted for ultrasonic testing. Therefore, when performing ultrasonic testing, it is not necessary to submerge the entire bonded substrate 15 in the medium, and the medium does not need to come into contact with the bonded interface 17. Therefore, ultrasonic testing can be performed without deteriorating the bonding state of the bonded substrate 15.

[0116] Next, a description will be given of a method for manufacturing a bonded substrate according to this embodiment, which is carried out using the bonding apparatus 2. In the method for manufacturing a bonded substrate according to this embodiment, two substrates 11, 13 are bonded to form a bonded substrate 15 (bonding step S30), and the bonded substrate 15 is inspected (inspection step S50). FIG. 9 is a flowchart showing the flow of each step in the method for manufacturing a bonded substrate according to this embodiment. Each step in the method for manufacturing a bonded substrate according to this embodiment will be described in detail below.

[0117] In the method for manufacturing a bonded substrate according to this embodiment, it is preferable to perform a plasma treatment step S10 and a bonding preparation step S20 before the bonding step S30, which will be described later. In the plasma treatment step S10, the bonding surfaces (surfaces 11a, 13a) of one or both of the two substrates 11, 13 are plasma-treated. In the bonding preparation step S20, a fluid containing water is supplied to the plasma-treated bonding surfaces to form hydroxyl groups on the bonding surfaces.

[0118] The plasma treatment step S10 is performed by the plasma treatment unit 10 (see FIG. 3). One of the substrates 11, 13 is carried into the plasma treatment unit 10. At this time, the surfaces to be bonded (front surfaces 11a, 13a) of the substrates 11, 13 are exposed upward, and the substrates 11, 13 are placed on the holding table 36 so that the surfaces opposite to the surfaces to be bonded (rear surfaces 11b, 13b) face the holding surface 36a of the holding table 36. The substrates 11, 13 are then held by the holding table 36.

[0119] Next, gas for plasma processing is supplied to the gas diffusion space 44a (see FIG. 3) of the gas injection head 44, and high-frequency power is applied to the gas injection head 44. This converts the gas in the gas diffusion space 44a into plasma, generating a gas in a plasma state containing ions and radicals.

[0120] Then, while the plasma gas is irradiated onto surfaces 11a, 13a of substrates 11, 13 under predetermined conditions, holding table 36 is rotated one or more times around a table rotation axis intersecting holding surface 36a, thereby subjecting surfaces 11a, 13a of substrates 11, 13 to plasma processing. Note that after plasma processing is performed on one of substrates 11, 13, the other of substrates 11, 13 may be subjected to plasma processing in the same manner.

[0121] 4, in the bonding preparation step S20, the plasma-treated substrates 11 and 13 are carried onto the holding table 56 of the bonding section 14. At this time, the substrates 11 and 13 are placed on the holding table 56 so that the surfaces 11a and 13a of the substrates 11 and 13 to be bonded are exposed upward, and the holding table 56 holds the substrates 11 and 13 by suction. Next, rotation of the holding table 56 is started, and pressurized water 92 is sprayed from a nozzle 90 toward the substrates 11 and 13. When the water comes into contact with the plasma-treated substrates 11 and 13, hydroxy groups are arranged on the surfaces (bonded surfaces) 11a and 13a of the substrates 11 and 13.

[0122] Next, a description will be given of the bonding step S30 in which two substrates 11, 13 are bonded together to form bonded substrate 15. The bonding step S30 is performed in bonding unit 14. Fig. 4 is a cross-sectional view schematically showing bonding unit 14 when bonding step S30 is performed.

[0123] 5, in the bonding step S30, one of the substrates 11, 13 is suction-held by a first holding unit 102, and the other of the substrates 11, 13 is suction-held by a second holding unit 104. At this time, the surfaces to be bonded (surfaces 11a, 13a) of the two substrates 11, 13 face each other. Then, the first holding unit 102 and the second holding unit 104 are brought relatively close to each other, so that the surfaces to be bonded (surfaces 11a, 13a) come into contact with each other.

[0124] In this case, hydrogen bonds are formed between the surface 11a of the first substrate 11 and the surface 13a of the second substrate 13 via hydroxy groups formed on one or both of the surfaces 11a and 13a by the plasma treatment step S10 and the bonding preparation step S20. This bonds the two substrates 11 and 13 together to form a bonded substrate 15. However, before the bonding strengthening step S70, which will be described later, is performed, it is relatively easy to peel off the bonded substrate 15 (separate the two substrates 11 and 13).

[0125] In the method for manufacturing a bonded substrate according to this embodiment, an inspection step S50 is performed after the bonding step S30. Note that before the bonding step S30 is performed, a sealing step S40 may be performed to seal the bonded interface 17 exposed on the outer periphery of the bonded substrate 15 from the atmosphere. Fig. 7(A) is a cross-sectional view schematically showing the bonded substrate 15 before the bonded interface 17 is sealed, and Fig. 7(B) is a cross-sectional view schematically showing the bonded substrate 15 after the bonded interface 17 has been sealed.

[0126] In the sealing step S40, bonded substrate 15 is placed on the upper surface of holding frame 142 so as to close through-hole 144. At this time, tube 148 surrounds bonded substrate 15. Thereafter, the pressure (internal pressure) in internal space 150 of tube 148 is changed to deform tube 148. More specifically, by making the inner diameter of tube 148 equal to or smaller than the diameter of bonded substrate 15, bonded interface 17 exposed on the outer periphery of bonded substrate 15 is sealed along the entire periphery. As a result, bonded interface 17 is closed from the outer periphery and is no longer exposed to the outside.

[0127] Next, the inspection step S50 will be described. In the inspection step S50, bonded substrate 15 is inspected. More specifically, in the inspection step S50, bonded substrate 15 is ultrasonically inspected by the above-described inspection units 16, 16a. Fig. 6 includes a cross-sectional view that schematically shows bonded substrate 15 being ultrasonically inspected.

[0128] In the ultrasonic inspection performed in the inspection step S50, a medium such as water is supplied to the supply nozzle 126 of the inspection unit 116 to fill the supply nozzle 126 with the medium, and the medium is supplied to the underside of the bonded substrate 15 (rear surface 13b of substrate 13) from the supply nozzle 126 from which the medium overflows. Then, ultrasonic waves are sent from the ultrasonic oscillator 120 of the ultrasonic sensor 118 to the bonded substrate 15 via the medium supplied to the underside of the bonded substrate 15.

[0129] The ultrasonic waves travel through bonded substrate 15 and are reflected by bonded interface 17. At this time, the vibration characteristics of the ultrasonic waves reflect the bonding state of bonded interface 17. Then, the ultrasonic waves returning from bonded substrate 15 are received by ultrasonic receiver 122, which generates an electrical signal reflecting the vibration characteristics of the ultrasonic waves and sends it to controller 22.

[0130] The inspection step S50 may be performed while the inspection unit 116 and the holder 110 are moved relatively in a direction parallel to the upper surface of the holder frame 112. Furthermore, the ultrasonic inspection may be performed while the bonded substrate 15 is rotated relatively to the supply nozzle 126. That is, the bonding apparatus 2 may include a moving unit that moves the inspection unit 116 and the holder 110, and a rotating unit that rotates the inspection unit 116 and the holder 110 relatively. This allows the bonding state of the bonded interface 17 over the entire area of ​​the bonded substrate 15 to be inspected.

[0131] Furthermore, the ultrasonic inspection in the inspection step S50 may be performed with the bonded substrate 15 tilted relative to the supply nozzle 126. In this case, a mechanism for changing the orientation (position changing unit) is provided in one or both of the inspection unit 116 and the holder 110. Furthermore, the ultrasonic inspection may be performed with the bonded substrate 15 vibrated relative to the supply nozzle 126. In this case, a vibration generating source (vibration unit) is provided in one or both of the inspection unit 116 and the holder 110.

[0132] When ultrasonic testing is performed with bonded substrate 15 tilted relative to supply nozzle 126, the outflow direction of the medium, such as water, can be controlled, making it easier to recover the medium. Furthermore, when ultrasonic testing is performed with bonded substrate 15 vibrating relative to supply nozzle 126, detachment of the medium from bonded substrate 15 is promoted, making it less likely that the medium will remain on bonded substrate 15.

[0133] As described above, in the manufacturing method of the bonded substrate according to this embodiment, the inspection step S50 is preferably carried out in at least one of a state in which the bonded substrate 15 is rotated, vibrated, or tilted relative to the supply nozzle 126.

[0134] After the inspection step S50, a determination step S60 is performed to determine whether the bonded state of the bonded substrate 15 is good or bad based on the inspection results of the inspection step S50. The determination step S60 is performed, for example, by the determination unit 24 of the controller 22 of the bonding apparatus 2. In the determination step S60, the determination unit 24 reads out the determination conditions stored in the memory unit of the controller 22, and compares the determination conditions with the inspection results to perform a determination.

[0135] For example, the storage unit stores as a judgment condition that no bonding defects (poor bonding, voids) are found at the bonding interface 17 of the bonded substrate 15. When the ultrasonic inspection results in no bonding defects being found at the bonding interface 17 of the bonded substrate 15, the judgment unit 24 judges that the bonding state is good. On the other hand, when the ultrasonic inspection results in any bonding defects being found at the bonding interface 17, the judgment unit 24 judges that the bonding state is poor.

[0136] However, the criteria for determining whether the bonded state is good or bad are not limited to this. For example, there may be an area in the bonded interface 17 where a certain degree of bond defects are allowed, and in this case, the bonded state may be determined to be good if the bond defects confirmed by ultrasonic testing are found only in that area. Also, a certain tolerance range may be set for the size or amount of the bond defects, and the bonded state may be determined to be good if the bond defects confirmed by ultrasonic testing fall within this tolerance range.

[0137] If the bonding state of bonded substrate 15 is determined to be good in determination step S60, it is preferable to carry out bond strengthening step S70, which performs a process to strengthen the bonding strength of bonded substrate 15. Bond strengthening step S70 is carried out by heating bonded substrate 15 in bond strengthening unit 18 of bonding apparatus 2. Fig. 8 is a perspective view that schematically shows how bonded substrate 15 determined to be good in bonding state is placed on heating holding table 152. Heating holding table 152 has a heater (heat source) such as an electric heating wire inside.

[0138] In the bonding strengthening step S70, the bonded substrate 15 is placed on the holding surface 154 of the heating and holding table 152, and the suction source is activated to hold the bonded substrate 15 by suction on the heating and holding table 152. Next, the heater is activated to transfer heat to the bonded substrate 15, heating the bonded substrate 15 to a predetermined temperature.

[0139] When the bonded substrate 15 is formed by bonding two substrates 11 and 13 together through hydrogen bonding, the adhesion between the two substrates 11 and 13 is improved when the bonded substrate 15 is heated to a predetermined temperature. This is partly because a dehydration condensation reaction occurs involving the hydroxy groups that constitute the hydrogen bonds, forming a covalent bond via oxygen atoms between the surface (bonded surface) 11a of the substrate 11 and the surface (bonded surface) 13a of the substrate 13. This bond is stronger than a hydrogen bond. Therefore, performing the bond strengthening step S70 improves the bond strength of the bonded substrate 15, making the two substrates 11 and 13 less likely to peel off when the bonded substrate 15 is subsequently processed.

[0140] The bond strengthening step S70 may be performed by a method other than heating the bonded substrate 15 by the bond strengthening unit 18 including the heating and holding table 152. For example, the bonded substrate 15 may be heated by laser annealing or by heating with a heat gun.

[0141] After the bonding strengthening step S70 is performed, the bonded substrate 15 is placed in a cassette placed on the cassette mounting table 8 and carried out from the bonding apparatus 2. Finally, the bonded substrate 15 is divided along the planned division lines to obtain individual device chips.

[0142] On the other hand, if the bonding state of bonded substrate 15 is determined to be poor in determination step S60, bond strengthening step S70 is not performed. If bond strengthening step S70 is not performed and the bond is not strengthened, bonded substrate 15 can be separated relatively easily, and substrates 11 and 13 separated from bonded substrate 15 can be used to manufacture a new bonded substrate.

[0143] If the bonding state of bonded substrate 15 is determined to be poor in determination step S60, a separation step S80 may be performed to separate bonded substrate 15 into two substrates 11 and 13. Separation step S80 may be performed, for example, by applying water to bonding interface 17 exposed on the side of bonded substrate 15 to deteriorate the bonding state. Alternatively, separation step S80 may be performed by inserting a nail into bonding interface 17. However, separation step S80 is not limited to this.

[0144] The separating step S80 may be performed outside the bonding apparatus 2. In this case, the bonded substrate 15 determined to have a poor bonding state passes through the bonding strengthening section 18 of the bonding apparatus 2, is placed in a cassette placed on the cassette mounting table 8, and is carried out from the bonding apparatus 2. Then, the separating step S80 is performed on the bonded substrate 15 taken out of the cassette.

[0145] Furthermore, after the separation step S80, a re-bonding step S90 may be performed in which two new substrates including one or both of the two substrates 11, 13 obtained by separation in the separation step S80 are bonded to form a new bonded substrate. If there are no particular abnormalities in the two substrates 11, 13 obtained in the separation step S80, the re-bonding step S90 may be performed in the bonding device 2 by re-introducing the substrates 11, 13 into the bonding device 2. Then, a new bonded substrate is manufactured from the two substrates 11, 13.

[0146] Furthermore, if an abnormality is found in one of the substrates 11, 13 obtained in the separation step S80, the abnormal substrate 11, 13 is preferably discarded. In this case, only the substrates 11, 13 for which no abnormality is found are re-introduced into the bonding apparatus 2, and a new bonded substrate is produced by bonding this substrate to another new substrate. Alternatively, it is preferable that the substrates 11, 13 for which an abnormality is found are subjected to a recycling process to remove the abnormality, and then the substrates may be re-introduced into the bonding apparatus 2.

[0147] As described above, according to the method for manufacturing a bonded substrate of this embodiment, ultrasonic testing of bonded substrate 15 can be performed without the medium for transmitting ultrasonic waves coming into contact with bonded interface 17, and therefore ultrasonic testing can be performed on bonded substrate 15 before the bond is strengthened. In other words, ultrasonic testing can be performed without deteriorating the bonded state of bonded substrate 15.

[0148] Furthermore, since ultrasonic testing can be performed before the bond of bonded substrate 15 is strengthened, any bond defects can be detected before the bond is strengthened. Before the bond is strengthened, bonded substrate 15 can be separated relatively easily, and the resulting substrates 11 and 13 can be used to manufacture a new bonded substrate. This improves the manufacturing efficiency of bonded substrate 15.

[0149] In the above embodiment, the ultrasonic inspection of bonded substrate 15 before the treatment for strengthening the bond is described as being performed while supplying a medium such as water below bonded substrate 15 by inspection unit 116 (see FIG. 6 ) of inspection section 16. However, one aspect of the present invention is not limited to this.

[0150] 7(A) and 7(B) is used to seal the bonded interface 17 exposed on the outer periphery of the bonded substrate 15, the medium is prevented from entering the bonded interface 17 by the tube 148. Therefore, the medium that transmits the ultrasonic waves may be supplied to an area other than the lower surface of the bonded substrate 15.

[0151] For example, if the bonded interface 17 is sealed by the tube 148, the ultrasonic inspection may be performed by submerging the tube 148 and the bonded substrate 15 in a medium. That is, the ultrasonic inspection of the bonded substrate 15 may be performed without using the inspection unit 116 having the supply nozzle 126.

[0152] 6, the inspection unit 116 has a tray portion 124, and the tray portion 124 receives and recovers the medium that overflows from the supply nozzle 126 that supplies the medium. However, one aspect of the present invention is not limited to this. That is, the inspection unit 116 does not need to have the tray portion 124, and the medium that overflows from the supply nozzle 126 may fall below the inspection unit 116.

[0153] In this case, the inspection section 16 may include a tray section (not shown) fixed below the holder 110 and the inspection unit 116. For example, the tray section is preferably formed to have the same size as the holder 110, and is preferably disposed in the inspection section 16 so as to receive any medium that spills out when the inspection unit 116 is ultrasonically inspecting any position on the bonded substrate 15. In this case, the inspection unit 116 is made lighter, and the inspection unit 116 can be moved efficiently relative to the bonded substrate 15.

[0154] In the above embodiment, the substrates 11 and 13 are bonded by plasma treatment, but this aspect of the present invention is not limited to this. The substrates 11 and 13 may be bonded at room temperature without plasma treatment, or may be bonded using an adhesive. Even in this case, information about the bonding state of the bonded substrate 15 can be obtained by performing the inspection step S50 using ultrasonic testing.

[0155] In addition, the structures and methods according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0156] 11,13 PCB 11a,13a surface 11b,13b Back side 15 Bonded substrate 17 Joint interface 2 Bonding equipment 4 Equipment base 6,8 Cassette stand 10 Plasma processing section 12 Joining preparation section 14 Joint 16,16a Inspection Department 18 Joint reinforcement part 20a, 20b, 20c, 20d, 20e, 20f Conveying passage 22 Controller 24 Judgment section 26 Chambers 26a,26b,26c opening 28 Processing Space 30 Gates 32 Piping 34 Exhaust system 36 Holding table 36a Holding surface 38 electrodes 40 Matching box 42 High frequency power supply 44 Gas ejection head 44a Gas diffusion space 44b, 44c, 44d Gas supply line 46 Bearings 48 Matching box 50 High frequency power supply 52a, 52b Piping 54a, 54b Gas supply source 56 Holding table 56a Holding surface 58 Frame 60 porous plate 62 Spindle 64 rotary joint 66 Rotational drive source 68 Encoder 70 Suction path 72 Suction source 74 Air supply source 76a Gate valve 76b Gate valve 78a, 78b Regulating valve 80 Pressure Gauge 82 Water Supply Unit 84 Rotational drive source 86 Rotating shaft 88 Arm 90 nozzles 92 water 94 Encoder 96 Water source 98 Air supply source 100 Junction chamber 102,104 Holding unit 102a,104a Holding surface 106 Shrinkage Cover 108 Elevating Axis 110 Holding part 112 Retaining frame 114 Through hole 116 Inspection Unit 118 Ultrasonic Sensor 120 Ultrasonic oscillator 122 Ultrasonic receiver 124 Tray section 126 supply nozzle 130 Outer wall 132 Medium supply channel 134 Medium Source 136 Medium recovery tank 138 Medium recovery path 140 Holding part 142 Retaining frame 144 Through Hole 146 Annular storage section 148 tubes 150 Interior Space 152 Heating holding table 154 Holding surface

Claims

1. a bonding step of bonding two substrates to form a bonded substrate; an inspection step of inspecting the bonded substrate, In the inspection step, an ultrasonic inspection is carried out by an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium for transmitting ultrasonic waves between the ultrasonic sensor and the bonded substrate, In the ultrasonic inspection, the medium is supplied from the supply nozzle to the underside of the bonded substrate, ultrasonic waves are transmitted from the ultrasonic oscillator to the bonded substrate through the medium supplied to the underside of the bonded substrate, and the ultrasonic waves returning from the bonded substrate are received by the ultrasonic receiver. A method for manufacturing a bonded substrate.

2. a bonding step of bonding two substrates to form a bonded substrate; a sealing step of sealing the bonding interface exposed on the outer periphery of the bonded substrate from the atmosphere; an inspection step of inspecting the bonded substrate, The inspection step includes performing an ultrasonic inspection using an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium for transmitting ultrasonic waves between the ultrasonic sensor and the bonded substrates, In the ultrasonic inspection, the medium is supplied from the supply nozzle to the underside of the bonded substrate, ultrasonic waves are transmitted from the ultrasonic oscillator to the bonded substrate through the medium supplied to the underside of the bonded substrate, and the ultrasonic waves returning from the bonded substrate are received by the ultrasonic receiver. A method for manufacturing a bonded substrate.

3. a bonding step of bonding two substrates to form a bonded substrate; a sealing step of sealing the bonding interface exposed on the outer periphery of the bonded substrate from the atmosphere; an inspection step of inspecting the bonded substrate, The inspection step includes performing an ultrasonic inspection using an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium for transmitting ultrasonic waves between the ultrasonic sensor and the bonded substrates, In the ultrasonic inspection, the medium is supplied from the supply nozzle to the bonded substrate, ultrasonic waves are transmitted from the ultrasonic oscillator to the bonded substrate via the medium supplied to the bonded substrate, and the ultrasonic waves returning from the bonded substrate are received by the ultrasonic receiver. A method for manufacturing a bonded substrate.

4. The ultrasonic inspection is performed in at least one of a state where the bonded substrate is rotated, vibrated, or tilted relative to the supply nozzle. The method for manufacturing the bonded substrate according to any one of claims 1 to 3.

5. a plasma treatment step of plasma-treating one or both surfaces to be bonded of the two substrates before the bonding step; The method further includes a bonding preparation step of supplying a fluid containing water to the plasma-treated bonded surface to form hydroxy groups on the bonded surface before the bonding step. The method for manufacturing the bonded substrate according to any one of claims 1 to 3.

6. a determining step of determining whether the bonding state of the bonded substrate is good or bad based on the inspection result of the inspecting step after the inspecting step; and a bonding strengthening step of performing a process to strengthen the bonding strength of the bonded substrate determined to have a good bonding state in the determining step. The method for manufacturing the bonded substrate according to any one of claims 1 to 3.

7. a determining step of determining whether the bonding state of the bonded substrate is good or bad based on the inspection result of the inspecting step after the inspecting step; a separating step of separating the bonded substrate, the bonded substrate being determined to have a poor bonding state in the determining step, into two substrates; a re-bonding step of bonding two new substrates including one or both of the two substrates obtained by separation in the separation step to form a new bonded substrate, The method for manufacturing the bonded substrate according to any one of claims 1 to 3.

8. a joining portion for joining two substrates; an inspection unit that inspects the bonded substrates bonded at the bonding unit, the inspection unit includes an ultrasonic inspection unit having an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle that supplies a medium between the ultrasonic sensor and the bonded substrates; The ultrasonic inspection unit supplies the medium to the underside of the bonded substrate from the supply nozzle, transmits ultrasonic waves from the ultrasonic oscillator to the bonded substrate via the medium supplied to the underside of the bonded substrate, and receives the ultrasonic waves returning from the bonded substrate with the ultrasonic receiver, thereby performing ultrasonic inspection. Bonding equipment.

9. a joining portion for joining two substrates; an inspection unit that inspects the bonded substrates bonded at the bonding unit, the inspection unit has an ultrasonic inspection unit including a holding unit for holding the bonded substrate, a tube surrounding the bonded substrate and capable of expanding and contracting in response to internal pressure, an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle for supplying a medium between the ultrasonic sensor and the bonded substrate; a pressure source for controlling the internal pressure is connected to the tube; the tube is deformed by the pressure supplied from the pressure supply source, thereby sealing the bonding interface exposed on the outer periphery of the bonded substrate at the holding portion; The ultrasonic inspection unit supplies the medium to the underside of the bonded substrate from the supply nozzle, transmits ultrasonic waves from the ultrasonic oscillator to the bonded substrate via the medium supplied to the underside of the bonded substrate, and receives the ultrasonic waves returning from the bonded substrate with the ultrasonic receiver, thereby performing ultrasonic inspection. Bonding equipment.

10. a joining portion for joining two substrates; an inspection unit that inspects the bonded substrates bonded at the bonding unit, the inspection unit has an ultrasonic inspection unit including a holding unit for holding the bonded substrate, a tube surrounding the bonded substrate and capable of expanding and contracting in response to internal pressure, an ultrasonic sensor including an ultrasonic oscillator and an ultrasonic receiver, and a supply nozzle for supplying a medium between the ultrasonic sensor and the bonded substrate; a pressure source for controlling the internal pressure is connected to the tube; the tube is deformed by the pressure supplied from the pressure supply source, thereby sealing the bonding interface exposed on the outer periphery of the bonded substrate at the holding portion; The ultrasonic inspection unit supplies the medium to the bonded substrate from the supply nozzle, transmits ultrasonic waves from the ultrasonic oscillator to the bonded substrate via the medium supplied to the bonded substrate, and receives the ultrasonic waves returning from the bonded substrate with the ultrasonic receiver, thereby performing ultrasonic inspection. Bonding equipment.

11. the inspection unit further includes one or more of a rotation unit that rotates the bonded substrate relative to the supply nozzle, a vibration unit that vibrates the bonded substrate, and a posture change unit that positions the bonded substrate in an inclined posture; The joining device according to any one of claims 8 to 10.

12. The method further includes a plasma processing unit that plasma-treats one or both of the surfaces to be bonded of the two substrates, and a bonding preparation unit that supplies a fluid containing water to the plasma-treated surfaces to be bonded to form hydroxyl groups on the surfaces to be bonded, The joining portion forms the joined substrate by contacting the two substrates with the joined surfaces facing each other. The joining device according to any one of claims 8 to 10.

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