Surface modification device and bonding strength evaluation method

Abstract

This surface reforming device uses a plasma of processing gas to reform a bonding surface of a substrate for bonding with another substrate. The surface reforming device is provided with a processing container, a measuring unit, and a control unit for controlling various units. The processing container is configured to be able to contain a substrate. The measuring unit measures a value indicating the amount of water in the processing container. The control unit, on the basis of the value indicating the amount of water in the processing container measured by the measuring unit, determines whether the bonding strength between one substrate and another substrate is sufficient, assuming that the one substrate was reformed in the processing container and was then bonded with the other substrate.

Description

[Technical field]

[0001] The present disclosure relates to a surface modification device and a bonding strength determination method. [Background technology]

[0002] Conventionally, a method for bonding substrates such as semiconductor wafers includes modifying the surfaces of the substrates to be bonded, making the modified substrate surfaces hydrophilic, and bonding the hydrophilized substrates together by van der Waals forces and hydrogen bonds (intermolecular forces).

[0003] The surface modification of the substrate is performed using a surface modification apparatus that accommodates the substrate in a processing chamber and modifies the surface of the accommodated substrate by plasma of a processing gas. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 084285 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that can determine whether or not the bonding strength between substrates to be bonded is good before the substrates are bonded to each other. [Means for solving the problem]

[0006] A surface modification apparatus according to one aspect of the present disclosure is a surface modification apparatus that modifies a bonding surface of a substrate to be bonded to another substrate by plasma of a processing gas. The surface modification apparatus includes a processing vessel, a measurement unit, and a control unit that controls each unit. The processing vessel is configured to be able to accommodate a substrate. The measurement unit measures a value indicating the amount of moisture in the processing vessel. The control unit determines whether the bonding strength between the substrate modified in the processing vessel and the other substrate is good or bad when the substrate is bonded to the other substrate based on the value indicating the amount of moisture in the processing vessel measured by the measurement unit. Effect of the Invention

[0007] Advantageous Effects of Invention According to the present disclosure, it is possible to determine whether the bonding strength between substrates to be bonded is good or bad before the substrates are bonded to each other. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic plan view showing the configuration of a joining system according to an embodiment. [Diagram 2] FIG. 2 is a schematic side view showing the configuration of the joining system according to the embodiment. [Diagram 3] FIG. 3 is a schematic side view of the upper wafer and the lower wafer according to the embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the configuration of a surface modification apparatus according to an embodiment. [Diagram 5] FIG. 5 is a schematic plan view showing the configuration of the bonding device according to the embodiment. [Figure 6] FIG. 6 is a schematic side view showing the configuration of the joining device according to the embodiment. [Figure 7] FIG. 7 is a schematic diagram showing an upper chuck and a lower chuck according to the embodiment. [Figure 8] FIG. 8 is a flowchart illustrating a procedure of a process executed by the bonding system according to the embodiment. [Figure 9] FIG. 9 is a diagram showing an example of a measurement result of the water amount in the processing container. [Figure 10]FIG. 10 is a diagram showing an example of the measurement result of the water amount in the processing container. [Figure 11] FIG. 11 is a diagram showing another example of the measurement results of the water amount in the processing container. [Figure 12] FIG. 12 is a flowchart showing the procedure of the joining process according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Various embodiments will be described in detail below with reference to the drawings. Note that the disclosed technology is not limited to the following embodiments.

[0010] However, when surface modification of a substrate is repeatedly performed in a processing vessel of a surface modification device, the amount of moisture in the processing vessel gradually decreases due to evacuation or the like. When the amount of moisture in the processing vessel decreases, the state of the plasma of the processing gas generated in the processing vessel changes, and the surface modification of the substrate is not performed sufficiently. As a result, the bonding strength between the substrates obtained when the modified substrate is bonded to another substrate may decrease. The decrease in bonding strength is undesirable because it can cause defects such as peeling of the substrate.

[0011] The quality of such bonding strength is generally judged using an inspection device or the like after the substrates are bonded. However, a method of judging the quality of the bonding strength after the substrates are bonded is not efficient from the viewpoint of improving productivity. Therefore, a technology that can judge the quality of the bonding strength between substrates to be bonded before the substrates are bonded is desired.

[0012] <Configuration of the joining system> First, the configuration of a bonding system 1 according to an embodiment will be described with reference to Figs. 1 to 3. Fig. 1 is a schematic plan view showing the configuration of the bonding system 1 according to the embodiment, and Fig. 2 is a schematic side view of the same. Fig. 3 is a schematic side view of an upper wafer W1 and a lower wafer W2 according to the embodiment. Note that, in order to make the description easier to understand, each of the drawings referred to below may show an orthogonal coordinate system in which the vertical upward direction is the positive direction of the Z axis.

[0013] The bonding system 1 shown in FIG. 1 forms a laminated wafer T by bonding a first substrate W1 and a second substrate W2 together.

[0014] The first substrate W1 is a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer on which a plurality of electronic circuits are formed. The second substrate W2 is a bare wafer on which no electronic circuits are formed. The first substrate W1 and the second substrate W2 have approximately the same diameter. The second substrate W2 may have electronic circuits formed thereon.

[0015] Hereinafter, the first substrate W1 will be referred to as the "upper wafer W1," and the second substrate W2 will be referred to as the "lower wafer W2." In other words, the upper wafer W1 is an example of the first substrate, and the lower wafer W2 is an example of the second substrate. Furthermore, the upper wafer W1 and the lower wafer W2 may be collectively referred to as the "wafer W."

[0016] 3, of the surfaces of the upper wafer W1, the surface to be bonded to the lower wafer W2 will be referred to as a "bonding surface W1j," and the surface opposite the bonding surface W1j will be referred to as a "non-bonding surface W1n." Also, of the surfaces of the lower wafer W2, the surface to be bonded to the upper wafer W1 will be referred to as a "bonding surface W2j," and the surface opposite the bonding surface W2j will be referred to as a "non-bonding surface W2n."

[0017] 1, the bonding system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are arranged in the positive direction of the X-axis in the order of the loading / unloading station 2 and the processing station 3. The loading / unloading station 2 and the processing station 3 are connected together.

[0018] The loading / unloading station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 includes a plurality of mounting plates 11. Cassettes C1, C2, and C3, each of which stores a plurality of substrates (e.g., 25 substrates) in a horizontal state, are placed on each of the mounting plates 11. For example, the cassette C1 is a cassette that stores an upper wafer W1, the cassette C2 is a cassette that stores a lower wafer W2, and the cassette C3 is a cassette that stores a laminated wafer T.

[0019] The transport area 20 is disposed adjacent to the mounting table 10 on the positive side in the X-axis direction. In the transport area 20, a transport path 21 extending in the Y-axis direction and a transport device 22 movable along the transport path 21 are provided.

[0020] The transfer device 22 is movable not only in the Y-axis direction but also in the X-axis direction and rotatable around the Z-axis. The transfer device 22 transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T between the cassettes C1 to C3 placed on the mounting plate 11 and a third processing block G3 of the processing station 3, which will be described later.

[0021] The number of cassettes C1 to C3 placed on the placement plate 11 is not limited to that shown in the figure. In addition to the cassettes C1, C2, and C3, a cassette for recovering defective substrates may be placed on the placement plate 11.

[0022] In the processing station 3, a plurality of processing blocks equipped with various devices, for example, three processing blocks G1, G2, and G3, are provided. For example, a first processing block G1 is provided on the front side (negative Y-axis side in FIG. 1) of the processing station 3, and a second processing block G2 is provided on the rear side (positive Y-axis side in FIG. 1) of the processing station 3. In addition, a third processing block G3 is provided on the loading / unloading station 2 side of the processing station 3 (negative X-axis side in FIG. 1).

[0023] The first processing block G1 is provided with a surface modification device 30 that modifies the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2 by plasma of a processing gas. The surface modification device 30 forms dangling bonds by plasma irradiation on the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2, thereby modifying the bonding surfaces W1j, W2j so that they are easily hydrophilized thereafter.

[0024] In the surface modification device 30, for example, a given process gas is excited to be plasmatized and ionized in a reduced pressure atmosphere. Ions of elements contained in the process gas are irradiated onto the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2, whereby the bonding surfaces W1j, W2j are plasma-processed and modified. Details of the surface modification device 30 will be described later.

[0025] The second processing block G2 includes a surface hydrophilizing device 40 and a bonding device 41. The surface hydrophilizing device 40 hydrophilizes the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2, for example, by pure water, and cleans the bonding surfaces W1j, W2j.

[0026] In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while rotating the upper wafer W1 or the lower wafer W2 held by, for example, a spin chuck. As a result, the pure water supplied onto the upper wafer W1 or the lower wafer W2 spreads over the bonding surfaces W1j, W2j of the upper wafer W1 or the lower wafer W2, and the bonding surfaces W1j, W2j are hydrophilized.

[0027] The bonding device 41 bonds the upper wafer W1 and the lower wafer W2. The bonding device 41 will be described in detail later.

[0028] As shown in FIG. 2, in the third processing block G3, transition (TRS) devices 50 and 51 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T are provided in two stages in this order from the bottom.

[0029] 1, a transfer region 60 is formed in an area surrounded by the first processing block G1, the second processing block G2, and the third processing block G3. A transfer device 61 is disposed in the transfer region 60. The transfer device 61 has a transfer arm that is movable, for example, in the vertical direction, the horizontal direction, and around the vertical axis.

[0030] The transfer device 61 moves within the transfer region 60 to transfer the upper wafer W1, the lower wafer W2, and the overlapped wafer T to given devices within the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the transfer region 60.

[0031] The bonding system 1 also includes a control device 4. The control device 4 controls the operation of the bonding system 1. The control device 4 is, for example, a computer, and includes a control unit 5 and a storage unit 6. The storage unit 6 stores programs for controlling various processes such as the bonding process. The control unit 5 controls the operation of the bonding system 1 by reading and executing the programs stored in the storage unit 6.

[0032] Such a program may be recorded on a computer-readable recording medium and installed from the recording medium into the storage unit 6 of the control device 4. Examples of computer-readable recording media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[0033] <Configuration of surface modification equipment> Next, the configuration of the surface modification apparatus 30 will be described with reference to Fig. 4. Fig. 4 is a schematic cross-sectional view showing the configuration of the surface modification apparatus 30 according to the embodiment.

[0034] 4, the surface modification apparatus 30 has a processing vessel 70 whose interior can be sealed. A loading / unloading port 71 for the upper wafer W1 or the lower wafer W2 is formed on a side surface of the processing vessel 70 on the transfer region 60 (see FIG. 1) side, and a gate valve 72 is provided at the loading / unloading port 71.

[0035] A stage 80 is disposed inside the processing vessel 70. The stage 80 is, for example, a lower electrode, and is made of a conductive material such as aluminum. The stage 80 is formed with pin through holes (not shown), and lifter pins (not shown) are housed in the pin through holes. The lifter pins are configured to be movable up and down by a lifting mechanism (not shown).

[0036] The top surface of the stage 80 is a horizontal surface that is circular in plan view and has a diameter larger than those of the upper wafer W1 and the lower wafer W2. A stage cover 90 is placed on the top surface of the stage 80, and the upper wafer W1 or the lower wafer W2 is placed on a placement portion 91 of the stage cover 90.

[0037] A ring-shaped partition plate 103 with multiple baffle holes is disposed between the stage 80 and the inner wall of the processing vessel 70. The partition plate 103 is also called an exhaust ring. The partition plate 103 divides the internal space of the processing vessel 70 into upper and lower spaces with the placement portion 91 as the boundary. The partition plate 103 also allows the atmosphere in the processing vessel 70 to be exhausted uniformly from within the processing vessel 70.

[0038] A power feed rod 104 made of a conductor is connected to the underside of the stage 80. A first high frequency power supply 106 is connected to the power feed rod 104 via a matching device 105 formed of, for example, a blocking capacitor. During plasma processing, a given high frequency voltage is applied to the stage 80 from the first high frequency power supply 106.

[0039] An upper electrode 110 is disposed inside the processing vessel 70. The upper surface of the stage 80 and the lower surface of the upper electrode 110 are disposed parallel to each other and facing each other with a given gap therebetween. The gap between the upper surface of the stage 80 and the lower surface of the upper electrode 110 is adjusted by a driving unit 81.

[0040] The upper electrode 110 is grounded and connected to a ground potential. Since the upper electrode 110 is grounded in this manner, damage to the lower surface of the upper electrode 110 during plasma processing can be suppressed.

[0041] In this manner, a high frequency voltage is applied from the first high frequency power supply 106 to the stage 80 serving as the lower electrode, whereby plasma is generated within the processing vessel 70 .

[0042] In the embodiment, the stage 80, the power feed rod 104, the matching box 105, the first high frequency power supply 106, the upper electrode 110, and the matching box are an example of a plasma generating mechanism that generates plasma of the processing gas in the processing vessel 70. The first high frequency power supply 106 is controlled by the control unit 5 of the control device 4 described above.

[0043] A hollow portion 120 is formed inside the upper electrode 110. A gas supply pipe 121 is connected to the hollow portion 120. A process gas supply mechanism 122, an inert gas supply mechanism 123, and a humidified gas supply mechanism 124 are connected to the gas supply pipe 121.

[0044] The process gas supply mechanism 122 supplies a process gas to the hollow portion 120 of the upper electrode 110 via the gas supply pipe 121. For example, oxygen gas, nitrogen gas, argon gas, or the like is used as the process gas. The process gas supply mechanism 122 has a process gas supply source 122a, a flow rate regulator 122b, and a valve 122c. The process gas supplied from the process gas supply source 122a is flow-controlled by the flow rate regulator 122b and the valve 122c, and is supplied to the hollow portion 120 of the upper electrode 110 via the gas supply pipe 121. The process gas supply mechanism 122 is an example of a first gas supply unit.

[0045] The inert gas supply mechanism 123 supplies an inert gas to the hollow portion 120 of the upper electrode 110 via the gas supply pipe 121. For example, nitrogen gas or argon gas is used as the inert gas. The inert gas supply mechanism 123 has an inert gas supply source 123a, a flow rate regulator 123b, and a valve 123c. The inert gas supplied from the inert gas supply source 123a is flow-controlled by the flow rate regulator 123b and the valve 123c, and is supplied to the hollow portion 120 of the upper electrode 110 via the gas supply pipe 121.

[0046] The humidified gas supply mechanism 124 supplies humidified gas (hereinafter referred to as "humidified gas") to the hollow portion 120 of the upper electrode 110 through the gas supply pipe 121. For example, humidified nitrogen gas or humidified argon gas is used as the humidified gas. Note that air whose temperature and humidity have been adjusted may be used as the humidified gas. The humidified gas supply mechanism 124 has a humidified gas supply source 124a, a flow rate regulator 124b, and a valve 124c. The humidified gas supplied from the humidified gas supply source 124a is flow-controlled by the flow rate regulator 124b and the valve 124c, and is supplied to the hollow portion 120 of the upper electrode 110 through the gas supply pipe 121. The humidified gas supply mechanism 124 is an example of a second gas supply unit.

[0047] A baffle plate 126 for promoting uniform diffusion of the processing gas, the inert gas, and the humidified gas is provided inside the hollow portion 120. A number of small holes are provided in the baffle plate 126. A number of gas outlets 125 for ejecting the processing gas, the inert gas, and the humidified gas from the hollow portion 120 into the processing vessel 70 are formed on the lower surface of the upper electrode 110.

[0048] The processing vessel 70 is formed with an intake port 130. The intake port 130 is connected to an intake pipe 132 which is in communication with a vacuum pump 131 which reduces the atmosphere inside the processing vessel 70 to a given vacuum level. An APC (Auto Pressure Controller) valve 133 is provided to the intake pipe 132. The inside of the processing vessel 70 is evacuated by the vacuum pump 131, and the pressure inside the processing vessel 70 is maintained at a given pressure by adjusting the opening of the APC valve 133.

[0049] The processing vessel 70 is provided with a spectrophotometer 141 capable of measuring the light emission data of each wavelength in the processing vessel 70. Specifically, the spectrophotometer 141 is provided in the processing vessel 70, disposed above the placement unit 91 and below the gas outlet 125. The spectrophotometer 141 is, for example, an OES (Optical Emission Spectroscopy) sensor, and can measure the light emission state of the plasma generated in the processing vessel 70. The spectrophotometer 141 may be a self-bias type OES sensor capable of generating plasma in a chamber held by the spectrophotometer 141 and measuring the light emission state of the plasma. The spectrophotometer 141 acquires light emission data of the processing gas supplied into the processing vessel 70, and measures the value of a peak occurring at a specific wavelength of the light emission data. The spectrophotometer 141 outputs data of the peak value occurring at a specific wavelength of the measured light emission data to the control unit 5 of the control device 4. The spectrophotometer 141 is an example of a measurement unit.

[0050] Further, the processing vessel 70 is fitted with a mass spectrometer 142 capable of analyzing the atmosphere in the processing vessel 70 with respect to the mass number of a specific substance. Specifically, the mass spectrometer 142 is disposed below the partition plate 103 and attached to the processing vessel 70. The mass spectrometer 142 is, for example, a quadrupole mass spectrometer (QMS), and measures an analysis value obtained by analyzing the atmosphere in the processing vessel 70 with respect to the mass number of a specific substance. The mass spectrometer 142 outputs data of the measured analysis value to the control unit 5 of the control device 4. Since the mass spectrometer 142 is disposed below the partition plate 103, it is possible to prevent the mass spectrometer 142 from being damaged by plasma. The mass spectrometer 142 is an example of a measurement unit.

[0051] <Configuration of the joining device> Next, the configuration of the joining device 41 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a schematic plan view showing the configuration of the joining device 41 according to the embodiment, and Fig. 6 is a schematic side view showing the configuration of the joining device 41 according to the embodiment.

[0052] 5, the bonding apparatus 41 has a processing container 190 whose interior can be sealed. A loading / unloading port 191 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is formed on a side surface of the processing container 190 on the transfer region 60 side, and an opening / closing shutter 192 is provided at the loading / unloading port 191.

[0053] The inside of the processing vessel 190 is divided into a transfer region T1 and a processing region T2 by an inner wall 193. The above-mentioned loading / unloading port 191 is formed on a side surface of the processing vessel 190 in the transfer region T1. In addition, a loading / unloading port 194 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is also formed in the inner wall 193.

[0054] In the transfer region T1, a transition 200, a substrate transfer mechanism 201, a reversing mechanism 220, and a position adjustment mechanism 210 are arranged, for example, from the load / unload port 191 side in this order.

[0055] The transition 200 temporarily holds the upper wafer W1, the lower wafer W2, and the overlapped wafer T. The transition 200 is formed in two stages, for example, and any two of the upper wafer W1, the lower wafer W2, and the overlapped wafer T can be held thereon at the same time.

[0056] The substrate transfer mechanism 201 has a transfer arm that is movable, for example, in the vertical direction (Z-axis direction), horizontal direction (Y-axis direction, X-axis direction), and direction around the vertical axis (θ direction). The substrate transfer mechanism 201 can transfer the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transfer region T1 or between the transfer region T1 and the processing region T2.

[0057] The position adjustment mechanism 210 adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2. Specifically, the position adjustment mechanism 210 has a base 211 equipped with a holding unit (not shown) that holds and rotates the upper wafer W1 and the lower wafer W2, and a detection unit 212 that detects the positions of the notch portions of the upper wafer W1 and the lower wafer W2. The position adjustment mechanism 210 adjusts the positions of the notch portions by detecting the positions of the notch portions of the upper wafer W1 and the lower wafer W2 using the detection unit 212 while rotating the upper wafer W1 and the lower wafer W2 held on the base 211. This adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2.

[0058] The inversion mechanism 220 inverts the upper wafer W1. Specifically, the inversion mechanism 220 has a holding arm 221 that holds the upper wafer W1. The holding arm 221 extends in the horizontal direction (X-axis direction). In addition, the holding arm 221 is provided with holding members 222 that hold the upper wafer W1 at, for example, four locations.

[0059] The holding arm 221 is supported by a drive unit 223 equipped with, for example, a motor. The holding arm 221 is rotatable about a horizontal axis by the drive unit 223. The holding arm 221 is also rotatable about the drive unit 223 and is movable in the horizontal direction (X-axis direction). Another drive unit (not shown) equipped with, for example, a motor is provided below the drive unit 223. The drive unit 223 can move in the vertical direction along a support column 224 extending in the vertical direction by the other drive unit.

[0060] In this manner, the upper wafer W1 held by the holding member 222 can be rotated around the horizontal axis and moved in the vertical and horizontal directions by the driving unit 223. In addition, the upper wafer W1 held by the holding member 222 can be rotated around the driving unit 223 and moved between the position adjustment mechanism 210 and the upper chuck 230 described later.

[0061] In the processing region T2, there are provided an upper chuck 230 that adsorbs and holds the upper surface (non-bonding surface W1n) of the upper wafer W1 from above, and a lower chuck 231 that adsorbs and holds the lower surface (non-bonding surface W2n) of the lower wafer W2 from below. The lower chuck 231 is provided below the upper chuck 230 and configured to be able to be arranged opposite the upper chuck 230. The upper chuck 230 and the lower chuck 231 are, for example, vacuum chucks.

[0062] 6, the upper chuck 230 is supported by a support member 270 provided above the upper chuck 230. The support member 270 is fixed to the ceiling surface of the processing vessel 190 via a plurality of support columns 271, for example.

[0063] An upper imaging unit 235 is provided on the side of the upper chuck 230 to capture an image of the upper surface (bonding surface W2j) of the lower wafer W2 held by the lower chuck 231. The upper imaging unit 235 may be, for example, a CCD camera.

[0064] The lower chuck 231 is supported by a first moving unit 250 provided below the lower chuck 231. The first moving unit 250 moves the lower chuck 231 in the horizontal direction (X-axis direction) as described below. In addition, the first moving unit 250 is configured to be capable of moving the lower chuck 231 in the vertical direction and to be rotatable around a vertical axis.

[0065] The first moving section 250 is provided with a lower imaging section 236 that images the lower surface (bonding surface W1j) of the first substrate W1 held by the upper chuck 230. The lower imaging section 236 may be, for example, a CCD camera.

[0066] The first moving part 250 is attached to a pair of rails 252, 252. The pair of rails 252, 252 are provided on the lower surface side of the first moving part 250 and extend in the horizontal direction (X-axis direction). The first moving part 250 is configured to be movable along the rails 252.

[0067] The pair of rails 252, 252 are disposed on the second moving part 253. The second moving part 253 is attached to a pair of rails 254, 254. The pair of rails 254, 254 are disposed on the lower surface side of the second moving part 253 and extend in the horizontal direction (Y-axis direction). The second moving part 253 is configured to be movable in the horizontal direction (Y-axis direction) along the rails 254. The pair of rails 254, 254 are disposed on a mounting table 255 provided on the bottom surface of the processing vessel 190.

[0068] The first moving unit 250, the second moving unit 253, etc. configure an alignment unit 256. The alignment unit 256 moves the lower chuck 231 in the X-axis direction, the Y-axis direction, and the θ direction to align the upper wafer W1 held by the upper chuck 230 with the lower wafer W2 held by the lower chuck 231 in the horizontal direction. The alignment unit 256 also moves the lower chuck 231 in the Z-axis direction to align the upper wafer W1 held by the upper chuck 230 with the lower wafer W2 held by the lower chuck 231 in the vertical direction.

[0069] Although the lower chuck 231 is moved in the X-axis direction, the Y-axis direction, and the θ-direction here, the alignment unit 256 may, for example, move the lower chuck 231 in the X-axis direction and the Y-axis direction and move the upper chuck 230 in the θ-direction. Also, although the lower chuck 231 is moved in the Z-axis direction here, the alignment unit 256 may, for example, move the upper chuck 230 in the Z-axis direction.

[0070] Next, the configurations of the upper chuck 230 and the lower chuck 231 will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing the upper chuck 230 and the lower chuck 231 according to the embodiment.

[0071] 7, the upper chuck 230 has a main body 260. The main body 260 is supported by a support member 270. A through hole 266 is formed in the support member 270 and the main body 260, passing through the support member 270 and the main body 260 in the vertical direction. The position of the through hole 266 corresponds to the center of the upper wafer W1 held by suction on the upper chuck 230. A pressing pin 281 of a striker 280 is inserted into the through hole 266.

[0072] Striker 280 is disposed on the upper surface of support member 270, and includes a pressing pin 281, an actuator portion 282, and a linear motion mechanism 283. Pressing pin 281 is a cylindrical member extending along the vertical direction, and is supported by actuator portion 282.

[0073] The actuator unit 282 generates a constant pressure in a fixed direction (vertically downward in this case) by air supplied from, for example, an electropneumatic regulator (not shown). The actuator unit 282 can control the pressing load applied to the center of the upper wafer W1 by contacting the center of the upper wafer W1 by air supplied from the electropneumatic regulator. In addition, the tip of the actuator unit 282 can be raised and lowered vertically by passing through the through hole 266 by air from the electropneumatic regulator.

[0074] The actuator section 282 is supported by a linear motion mechanism 283. The linear motion mechanism 283 moves the actuator section 282 in the vertical direction by a drive section having a built-in motor, for example.

[0075] The striker 280 is configured as described above, and controls the movement of the actuator part 282 by the linear motion mechanism 283, and controls the pressing load of the pressing pin 281 on the upper wafer W1 by the actuator part 282. As a result, the striker 280 presses the center of the upper wafer W1 held by suction on the upper chuck 230 to bring it into contact with the lower wafer W2.

[0076] A plurality of pins 261 that come into contact with the upper surface (non-bonding surface W1n) of the upper wafer W1 are provided on the lower surface of the main body 260. The plurality of pins 261 have, for example, a diameter dimension of 0.1 mm to 1 mm and a height of several tens of μm to several hundreds of μm. The plurality of pins 261 are evenly arranged at intervals of, for example, 2 mm.

[0077] The upper chuck 230 includes a plurality of suction portions for suctioning the upper wafer W1 in a portion of the region where the plurality of pins 261 are provided. Specifically, a lower surface of the main body portion 260 of the upper chuck 230 is provided with a plurality of outer suction portions 391 and a plurality of inner suction portions 392 for suctioning the upper wafer W1 by vacuum drawing. The plurality of outer suction portions 391 and the plurality of inner suction portions 392 have suction regions having an arc shape in a plan view. The plurality of outer suction portions 391 and the plurality of inner suction portions 392 have the same height as the pins 261.

[0078] The outer suction portions 391 are disposed on the outer periphery of the main body portion 260. The outer suction portions 391 are connected to a suction device (not shown) such as a vacuum pump, and suction the outer periphery of the upper wafer W1 by vacuum drawing.

[0079] The multiple inner suction portions 392 are arranged side by side along the circumferential direction, radially inward of the main body portion 260 from the multiple outer suction portions 391. The multiple inner suction portions 392 are connected to a suction device (not shown), such as a vacuum pump, and suck the region between the outer periphery and the center of the upper wafer W1 by vacuum drawing.

[0080] The lower chuck 231 has a main body 290 having a diameter equal to or larger than that of the lower wafer W2. Here, the lower chuck 231 having a diameter larger than that of the lower wafer W2 is shown. The upper surface of the main body 290 is an opposing surface that faces the lower surface (non-bonding surface W2n) of the lower wafer W2.

[0081] A plurality of pins 291 that come into contact with the lower surface (non-bonding surface Wn2) of the lower wafer W2 are provided on the upper surface of the main body 290. The plurality of pins 291 have, for example, a diameter dimension of 0.1 mm to 1 mm and a height of several tens of μm to several hundreds of μm. The plurality of pins 291 are evenly arranged at intervals of, for example, 2 mm.

[0082] Further, on the upper surface of the main body 290, a lower rib 292 is provided in an annular shape outside the multiple pins 291. The lower rib 292 is formed in an annular shape and supports the outer periphery of the lower wafer W2 over the entire circumference.

[0083] Furthermore, the main body 290 has a plurality of lower suction ports 293. The plurality of lower suction ports 293 are provided in a suction region surrounded by the lower ribs 292. The plurality of lower suction ports 293 are connected to a suction device (not shown) such as a vacuum pump via a suction pipe (not shown).

[0084] The lower chuck 231 reduces the pressure in the suction region surrounded by the lower ribs 292 by vacuuming the suction region through the lower suction ports 293. As a result, the lower wafer W2 placed in the suction region is suctioned and held by the lower chuck 231.

[0085] Since the lower ribs 292 support the entire outer periphery of the lower surface of the lower wafer W2, the lower wafer W2 is appropriately vacuumed up to the outer periphery. This allows the entire surface of the lower wafer W2 to be suction-held. In addition, since the lower surface of the lower wafer W2 is supported by the multiple pins 291, the lower wafer W2 is easily peeled off from the lower chuck 231 when the vacuum of the lower wafer W2 is released.

[0086] <Specific operation of the joining system> As a result of extensive research, the inventors of the present application have discovered that there is a correlation between the amount of moisture in the processing vessel 70 in the surface modification apparatus 30 and the bonding strength between the upper wafer W1 and the lower wafer W2 obtained when the upper wafer W1 modified in the processing vessel 70 is bonded to the lower wafer W2.

[0087] For example, in the surface modification apparatus 30, when the surface modification process is repeatedly performed in the processing vessel 70, the amount of moisture in the processing vessel 70 gradually decreases due to evacuation or the like. When the amount of moisture in the processing vessel 70 decreases, the state of the plasma of the processing gas generated in the processing vessel 70 changes, and the surface modification of the upper wafer W1 and the lower wafer W2 is not performed sufficiently. It is considered that this insufficient surface modification is a factor that reduces the bonding strength between the upper wafer W1 and the lower wafer W2.

[0088] Therefore, in the bonding system 1 according to the embodiment, before performing a series of bonding processes, a value indicating the amount of moisture in the processing vessel 70 is measured using a measuring device such as a spectrophotometer 141, and the bonding strength is judged to be good or bad based on the measured value indicating the amount of moisture in the processing vessel 70.

[0089] Hereinafter, the procedure of the bonding strength determination process executed by the bonding system 1 will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the procedure of the process executed by the bonding system 1 according to the embodiment. Note that the various processes shown in Fig. 8 are executed based on the control by the control unit 5 of the control device 4.

[0090] 8, the controller 5 measures a value indicating the amount of moisture in the processing vessel 70 (step S101). For example, the controller 5 controls the spectrophotometer 141 and the processing gas supply mechanism 122 to obtain light emission data of the processing gas supplied into the processing vessel 70, and measures a peak value occurring at a specific wavelength of the light emission data as a value indicating the amount of moisture in the processing vessel 70.

[0091] Controller 5 may further control mass spectrometer 142 to analyze the atmosphere in processing vessel 70 with respect to the mass number of water, and measure the analysis value as a value indicating the amount of moisture in processing vessel 70.

[0092] Next, the control unit 5 determines whether the bonding strength between the upper wafer W1 and the lower wafer W2, assuming that the upper wafer W1 modified in the processing container 70 is bonded to the lower wafer W2, is good or bad based on a value indicating the measured amount of moisture in the processing container 70 (step S102).

[0093] Here, an example of determining whether the bonding strength is good or bad based on a value indicating the amount of moisture in the processing vessel 70 will be described with reference to FIGS. 9 and 10. FIGS. 9 and 10 are diagrams showing an example of a measurement result of the amount of moisture in the processing vessel 70. FIG. 9 shows emission data of each wavelength in the processing vessel 70 immediately after it is opened to the atmosphere during maintenance. FIG. 9 shows emission data measured by the spectrophotometer 141 when plasma of nitrogen gas, which is the processing gas, is generated in the processing vessel 70. The plasma of nitrogen gas contains nitrogen ions of a first excitation level (1st POS) and nitrogen ions of a second excitation level (2nd POS) having higher activity than the nitrogen ions of the first excitation level. The wavelength of the nitrogen ions of the first excitation level is within a range of about 530 nm to 800 nm, and the wavelength of the nitrogen ions of the second excitation level is within a range of about 280 nm to 440 nm. The emission data shown in FIG. 9 shows that when the processing vessel 70 is opened to the atmosphere during maintenance, almost no nitrogen ions of the first excitation level are generated. This is believed to be because the amount of moisture in the processing vessel 70 increases due to exposure to the atmosphere, and the energy of the nitrogen ions at the first excitation level is transferred to the moisture (H2O) present in the processing vessel 70, causing the nitrogen ions at the first excitation level to disappear from the processing vessel 70.

[0094] 10 shows emission data at each wavelength in the processing vessel 70 after the surface modification of the upper wafer W1 has been repeated a predetermined number of times. FIG. 10 shows emission data measured by the spectrophotometer 141 when plasma of nitrogen gas, which is the processing gas, is generated in the processing vessel 70. The emission data shown in FIG. 10 indicates that the amount of nitrogen ions at the first excitation level increases when the surface modification of the upper wafer W1 is repeatedly performed in the processing vessel 70. This is because, when the surface modification is repeatedly performed, the amount of moisture in the processing vessel 70 decreases due to evacuation or the like, making it difficult for the energy of the nitrogen ions at the first excitation level to be transferred to moisture (H2O), and the remaining nitrogen ions at the first excitation level increase.

[0095] The control unit 5 judges whether the bonding strength between the upper wafer W1 and the lower wafer W2 is good or bad based on the value of a peak occurring at a wavelength corresponding to nitrogen ions of the first excitation level of the light emission data measured by the spectrophotometer 141. As the amount of moisture in the processing vessel 70 decreases, the value of the peak occurring at a wavelength corresponding to nitrogen ions of the first excitation level increases. Therefore, it is possible to judge whether the bonding strength between the upper wafer W1 and the lower wafer W2 decreases below the normal range due to the decrease in the amount of moisture in the processing vessel 70 from the value of the peak occurring at the wavelength corresponding to nitrogen ions of the first excitation level. For example, the control unit 5 judges whether the value of the peak occurring at the wavelength corresponding to nitrogen ions of the first excitation level measured by the spectrophotometer 141 is equal to or greater than a first threshold value. The first threshold value is a value that can be regarded as the bonding strength between the upper wafer W1 and the lower wafer W2 decreasing below the normal range. For example, the first threshold value is a value of one peak arbitrarily selected from the values ​​of multiple peaks occurring when the bonding strength between the upper wafer W1 and the lower wafer W2 falls within the normal range. When the value of the peak occurring at the wavelength corresponding to the nitrogen ions of the first excitation level measured by the spectrophotometer 141 is equal to or greater than the first threshold value, the control unit 5 determines that the bonding strength between the upper wafer W1 and the lower wafer W2 is lower than the normal range and is defective. On the other hand, when the value of the peak occurring at the wavelength corresponding to the nitrogen ions of the first excitation level measured by the spectrophotometer 141 is less than the first threshold value, the control unit 5 determines that the bonding strength between the upper wafer W1 and the lower wafer W2 is within the normal range and is good.

[0096] In addition, when the control unit 5 measures the analytical value obtained by analyzing the atmosphere inside the processing vessel 70 using the mass spectrometer 142 in terms of the mass number of water as a value indicating the amount of moisture inside the processing vessel 70, the control unit 5 may further use such analytical value to determine whether the bonding strength is good or bad.

[0097] Fig. 11 is a diagram showing another example of the measurement results of the amount of moisture in the processing vessel 70. Fig. 11 shows analytical value data obtained by analyzing the atmosphere in the processing vessel 70 with respect to the mass number (m / z=18) of water (H2O) when the processing vessel 70 is opened to the atmosphere and then evacuated. Fig. 11 shows analytical value data measured by the mass spectrometer 142. The analytical value data shown in Fig. 11 indicates that when the surface modification of the upper wafer W1 is repeated a predetermined number of times in the processing vessel 70, the amount of moisture in the processing vessel 70 gradually decreases due to the evacuation.

[0098] The control unit 5 judges whether the bonding strength between the upper wafer W1 and the lower wafer W2 is good or bad based on the value of a peak occurring at a wavelength corresponding to nitrogen ions of the first excitation level of the light emission data measured by the spectrophotometer 141 and the analysis value measured by the mass spectrometer 142. As the amount of moisture in the processing vessel 70 decreases, the analysis value decreases. Therefore, it is possible to judge from the analysis value whether the bonding strength between the upper wafer W1 and the lower wafer W2 decreases below the normal range due to the decrease in the amount of moisture in the processing vessel 70. For example, when the value of a peak occurring at a wavelength corresponding to nitrogen ions of the first excitation level of the light emission data measured by the spectrophotometer 141 is less than the first threshold, the control unit 5 further judges whether the analysis value measured by the mass spectrometer 142 is equal to or less than the second threshold. The second threshold is a value at which the bonding strength between the upper wafer W1 and the lower wafer W2 can be regarded as being lower than the normal range. For example, the second threshold is an analysis value measured when the bonding strength between the upper wafer W1 and the lower wafer W2 falls within the normal range. When the analysis value measured by the mass spectrometer 142 is equal to or less than the second threshold, the control unit 5 determines that the bonding strength between the upper wafer W1 and the lower wafer W2 is lower than the normal range and is defective. On the other hand, when the analysis value measured by the mass spectrometer 142 is greater than the second threshold, the control unit 5 determines that the bonding strength between the upper wafer W1 and the lower wafer W2 is within the normal range and is good. In this way, the control unit 5 can determine with high accuracy whether the bonding strength is good or not by using both the measurement results by the spectrophotometer 141 and the measurement results by the mass spectrometer 142.

[0099] Returning to the description of Fig. 8, when the control unit 5 determines that the bonding strength between the upper wafer W1 and the lower wafer W2 is poor (step S103; Yes), the control unit 5 adjusts the amount of moisture in the processing vessel 70 by supplying humidified gas from the humidified gas supply mechanism 124 into the processing vessel 70 (step S104). This allows the control unit 5 to suppress a decrease in the bonding strength caused by a decrease in the amount of moisture in the processing vessel 70 before performing a series of bonding processes. Thereafter, the control unit 5 repeats the processes of steps S101 to S104 until the bonding strength becomes good.

[0100] When the control unit 5 determines that the bonding strength between the upper wafer W1 and the lower wafer W2 is good (step S103; No), the bonding system 1 performs a bonding process (step S105). Here, the procedure of the bonding process will be described with reference to Fig. 12. Fig. 12 is a flowchart showing the procedure of the bonding process according to the embodiment.

[0101] First, the cassette C1 accommodating a plurality of upper wafers W1, the cassette C2 accommodating a plurality of lower wafers W2, and an empty cassette C3 are placed on a predetermined placement plate 11 of the load / unload station 2. Thereafter, the upper wafer W1 in the cassette C1 is removed by the transfer device 22 and transferred to the transition device 50 arranged in the third processing block G3.

[0102] Next, the upper wafer W1 is transported by the transport device 61 to the surface modification device 30 in the first processing block G1. In the surface modification device 30, nitrogen gas, which is a processing gas, is excited to be turned into plasma and ionized in a predetermined reduced pressure atmosphere. The nitrogen ions are irradiated onto the bonding surface W1j of the upper wafer W1, and the bonding surface W1j is subjected to plasma processing. As a result, the bonding surface W1j of the upper wafer W1 is modified (step S201).

[0103] Next, the upper wafer W1 is transferred by the transfer device 61 to the surface hydrophilization device 40 in the first processing block G1. In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 while rotating the upper wafer W1 held by the spin chuck. This makes the bonding surface W1j of the upper wafer W1 hydrophilic. In addition, the bonding surface W1j of the upper wafer W1 is cleaned by the pure water (step S202).

[0104] Next, the upper wafer W1 is transferred to the bonding device 41 in the second processing block G2 by the transfer device 61. The upper wafer W1 carried into the bonding device 41 is transferred to the position adjustment mechanism 210 via the transition 200, and its horizontal orientation is adjusted by the position adjustment mechanism 210 (step S203).

[0105] Thereafter, the upper wafer W1 is transferred from the position adjustment mechanism 210 to the reversing mechanism 220, and the upper wafer W1 is reversed upside down by the reversing mechanism 220 (step S204). Specifically, the bonding surface W1j of the upper wafer W1 is directed downward.

[0106] Next, the upper wafer W1 is transferred from the reversing mechanism 220 to the upper chuck 230, and the upper wafer W1 is attracted and held by the upper chuck 230 (step S205).

[0107] The processing of the lower wafer W2 overlaps with the processing of steps S101 to S105 for the upper wafer W1. First, the transfer device 22 removes the lower wafer W2 from the cassette C2 and transfers it to the transition device 50 arranged in the third processing block G3.

[0108] Next, the lower wafer W2 is transferred by the transfer device 61 to the surface modification device 30, where the bonding surface W2j of the lower wafer W2 is modified (step S206). Note that the modification of the bonding surface W2j of the lower wafer W2 in step S206 is similar to the above-mentioned step S201.

[0109] Thereafter, the lower wafer W2 is transferred by the transfer device 61 to the surface hydrophilization device 40, where the bonding surface W2j of the lower wafer W2 is hydrophilized and cleaned (step S207). Note that the hydrophilization and cleaning of the bonding surface W2j of the lower wafer W2 in step S207 are similar to those in step S202 described above.

[0110] Thereafter, the lower wafer W2 is transferred to the bonding apparatus 41 by the transfer device 61. The lower wafer W2 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 210 via the transition 200. Then, the horizontal orientation of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (step S208).

[0111] Thereafter, the lower wafer W2 is transferred to the lower chuck 231 and is attracted and held by the lower chuck 231 with the notch portion facing a predetermined direction (step S209).

[0112] Next, the horizontal positions of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted (step S210).

[0113] Next, the vertical positions of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted (step S211). Specifically, the first moving part 250 moves the lower chuck 231 vertically upward, thereby bringing the lower wafer W2 closer to the upper wafer W1.

[0114] Next, after the suction and holding of the upper wafer W1 by the multiple inner suction portions 392 is released (step S212), the pressing pin 281 of the striker 280 is lowered to press down the center of the upper wafer W1 (step S213).

[0115] When the center of the upper wafer W1 comes into contact with the center of the lower wafer W2 and the center of the upper wafer W1 and the center of the lower wafer W2 are pressed with a predetermined force by the striker 280, bonding is started between the pressed center of the upper wafer W1 and the center of the lower wafer W2. That is, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are modified, first, van der Waals force (intermolecular force) is generated between the bonding surfaces W1j, W2j, and the bonding surfaces W1j, W2j are bonded to each other. Furthermore, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrophilized, the hydrophilic groups between the bonding surfaces W1j, W2j are hydrogen-bonded, and the bonding surfaces W1j, W2j are firmly bonded to each other. In this way, a bonding region is formed.

[0116] Thereafter, a bonding wave is generated between the upper wafer W1 and the lower wafer W2, in which the bonding area expands from the center to the outer periphery of the upper wafer W1 and the lower wafer W2. Then, the upper wafer W1 is released from suction and holding by the outer suction parts 391 (step S214). This causes the outer periphery of the upper wafer W1 that was suction-held by the outer suction parts 391 to fall. As a result, the entire bonding surface W1j of the upper wafer W1 and the entire bonding surface W2j of the lower wafer W2 come into contact with each other, and the overlapped wafer T is formed.

[0117] Thereafter, the pressing pins 281 are raised to the upper chuck 230, and the lower wafer W2 is released from the suction hold by the lower chuck 231. Thereafter, the overlapped wafer T is carried out of the bonding apparatus 41 by the transfer device 61. In this manner, a series of bonding processes is completed.

[0118] <Effects> The surface modification apparatus (e.g., surface modification apparatus 30) according to the embodiment is a surface modification apparatus that modifies a bonding surface (e.g., bonding surface W1j) of a substrate (e.g., upper wafer W1) to be bonded to another substrate (e.g., lower wafer W2) by plasma of a processing gas. The surface modification apparatus includes a processing vessel (e.g., processing vessel 70), a measuring unit (e.g., spectrophotometer 141, mass spectrometer 142), and a control unit (e.g., control unit 5) that controls each unit. The processing vessel is configured to accommodate a substrate. The measuring unit measures a value indicating the amount of moisture in the processing vessel. The control unit judges whether the bonding strength between the substrate modified in the processing vessel and the other substrate is good or bad when the substrate is assumed to be bonded to the other substrate based on the value indicating the amount of moisture in the processing vessel measured by the measuring unit. This makes it possible to judge whether the bonding strength between the substrates to be bonded is good or bad before bonding the substrates.

[0119] Furthermore, the measurement unit (e.g., spectrophotometer 141) may acquire light emission data of the processing gas supplied into the processing vessel, and measure a peak value occurring at a specific wavelength of the light emission data as a value indicating the amount of moisture in the processing vessel. The control unit may determine whether the bonding strength is good or bad based on the peak value occurring at the specific wavelength of the light emission data measured by the measurement unit. This allows the bond strength to be determined with high accuracy from, for example, the peak value occurring at a wavelength corresponding to nitrogen ions at the first excitation level of the light emission data.

[0120] Moreover, the surface modification apparatus according to the embodiment may include a plurality of measuring units. The plurality of measuring units may include a first measuring unit (for example, a spectrophotometer 141) and a second measuring unit (for example, a mass spectrometer 142). The first measuring unit may acquire light emission data of the processing gas supplied into the processing vessel, and measure a peak value occurring at a specific wavelength of the light emission data as a value indicating the amount of moisture in the processing vessel. The second measuring unit may further measure an analysis value obtained by analyzing the atmosphere in the processing vessel in terms of the mass number of water as a value indicating the amount of moisture in the processing vessel. The control unit may determine whether the bonding strength is good or bad based on the peak value occurring at a specific wavelength of the light emission data measured by the first measuring unit and the analysis value measured by the second measuring unit. In this way, since both the measurement results by the first measuring unit and the measurement results by the second measuring unit are used, the bonding strength can be determined to be good or bad with higher accuracy.

[0121] Moreover, the surface modification apparatus according to the embodiment may further include a humidified gas supply unit (e.g., humidified gas supply mechanism 124) that supplies humidified gas into the processing vessel. When the control unit determines that the bonding strength is poor, the control unit may adjust the amount of moisture in the processing vessel by supplying humidified gas from the humidified gas supply unit into the processing vessel. This makes it possible to suppress a decrease in bonding strength caused by a decrease in the amount of moisture in the processing vessel before bonding the substrates.

[0122] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0123] For example, in the above embodiment, the humidified gas supply mechanism 124 is operated to supply the humidified gas into the processing vessel 70, but the disclosed technology is not limited to this. For example, the processing vessel 70 may be opened to the atmosphere, and a gas containing moisture in the atmosphere may be supplied into the processing vessel 70 as a humidified gas. [Explanation of symbols]

[0124] 1 Joining System 5. Control section 30 Surface modification equipment 41 Joining equipment 70 Processing vessel 122 Processing gas supply mechanism 123 Inert gas supply mechanism 124 Humidified gas supply mechanism 141 Spectrophotometer 142 Mass spectrometer W1 Upper wafer W2 Lower wafer

Claims

1. A surface modification apparatus for modifying a bonding surface of a substrate to be bonded to another substrate by plasma of a processing gas, comprising: a processing vessel capable of accommodating the substrate; A measurement unit that measures a value indicating a moisture content in the treatment container; A control unit that controls each part Equipped with The control unit is determining whether or not a bonding strength between the substrate modified in the processing vessel and the other substrate is good when the substrate is bonded to the other substrate based on a value indicating the amount of moisture in the processing vessel measured by the measuring unit; The measurement unit includes: acquiring light emission data of the processing gas supplied into the processing vessel, and measuring a peak value occurring at a specific wavelength of the light emission data as a value indicating a moisture content in the processing vessel; The control unit is determining whether the bonding strength is good or bad based on a peak value generated at a specific wavelength of the light emission data measured by the measurement unit; Surface modification equipment.

2. the processing vessel is provided with a mounting part on which the substrate is mounted, and a gas outlet arranged above the mounting part and configured to eject the processing gas into the processing vessel; The surface modification apparatus according to claim 1 , wherein the measurement unit is disposed above the placement unit and below the gas outlet.

3. A surface modification apparatus for modifying a bonding surface of a substrate to be bonded to another substrate by plasma of a processing gas, comprising: a processing vessel capable of accommodating the substrate; A measurement unit that measures a value indicating a moisture content in the treatment container; A control unit that controls each part Equipped with The control unit is determining whether or not a bonding strength between the substrate modified in the processing vessel and the other substrate is good when the substrate is bonded to the other substrate based on a value indicating the amount of moisture in the processing vessel measured by the measuring unit; A plurality of the measuring units are provided, The plurality of measurement units include a first measurement unit that acquires optical emission data of the processing gas supplied into the processing vessel and measures a peak value generated at a specific wavelength of the optical emission data as a value indicating a moisture content in the processing vessel; a second measurement unit that further measures an analysis value obtained by analyzing the atmosphere in the treatment vessel with respect to the mass number of water as a value indicating the amount of moisture in the treatment vessel; Equipped with The control unit is determining whether the bonding strength is good or bad based on a peak value occurring at a specific wavelength of the light emission data measured by the first measurement unit and the analysis value measured by the second measurement unit; Surface modification equipment.

4. the processing vessel is provided with a mounting part for mounting the substrate thereon, a gas outlet disposed above the mounting part for ejecting the processing gas into the processing vessel, and a partition plate for dividing an internal space of the processing vessel into upper and lower parts with the mounting part as a boundary, the first measuring unit is disposed above the placement unit and below the gas outlet, The surface modification apparatus according to claim 3 , wherein the second measuring section is disposed below the partition plate.

5. A humidified gas supply unit is further provided for supplying humidified gas into the processing vessel. The surface modification apparatus according to any one of claims 1 to 4, wherein the control unit adjusts the amount of moisture in the processing vessel by supplying the humidified gas from the humidified gas supply unit into the processing vessel when the control unit determines that the bonding strength is poor.

6. a measuring step of measuring a value indicating a moisture content in a processing vessel capable of accommodating the substrate in a surface modification device that modifies a bonding surface of a substrate to be bonded to another substrate by plasma of a processing gas; a determining step of determining whether or not the bonding strength between the substrate modified in the processing vessel and the other substrate is good when the substrate is bonded to the other substrate, based on a value indicating the measured amount of moisture in the processing vessel; Including, The measuring step includes acquiring light emission data of the processing gas supplied into the processing vessel, and measuring a peak value occurring at a specific wavelength of the light emission data as a value indicating a moisture content in the processing vessel; The determining step determines whether the bonding strength is good or bad based on a peak value generated at a specific wavelength of the measured light emission data. Method for determining joint strength.

7. A surface modification apparatus for modifying a bonding surface of a substrate to be bonded to another substrate by plasma of a processing gas, comprising: a measuring step for measuring a value indicating a moisture content in a processing vessel capable of accommodating the substrate; a determining step of determining whether or not the bonding strength between the substrate modified in the processing vessel and the other substrate is good when the substrate is bonded to the other substrate, based on a value indicating the measured amount of moisture in the processing vessel; Including, The measuring step includes: a first measuring step of acquiring light emission data of the processing gas supplied into the processing vessel, and measuring a peak value generated at a specific wavelength of the light emission data as a value indicating a moisture content in the processing vessel; a second measuring step of analyzing the atmosphere in the treatment vessel with respect to the mass number of water and further measuring the analytical value as a value indicating the moisture content in the treatment vessel; Including, The determination step determines whether the bonding strength is good or bad based on a peak value occurring at a specific wavelength of the light emission data measured in the first measurement step and the analysis value measured in the second measurement step. Method for determining joint strength.

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