JP7365827B2 - Joining system and joining method - Google Patents

Description

The present disclosure relates to a joining system and a joining method.

The bonding system described in Patent Document 1 includes a surface modification device that modifies the surfaces of substrates to be bonded, a surface hydrophilization device that hydrophilizes the surface of the substrate modified by the surface modification device, and and a bonding device for bonding substrates whose surfaces have been made hydrophilic with a surface hydrophilic device. In this bonding system, a surface modification device performs plasma treatment on the surface of a substrate to modify the surface, and then a surface hydrophilization device supplies pure water to the surface of the substrate to make the surface hydrophilic. Thereafter, in a bonding device, the two substrates placed facing each other are bonded by van der Waals force and hydrogen bonding.

Japanese Patent Application Publication No. 2012-175043

One aspect of the present disclosure provides a technique that can suppress generation of a gap between a first substrate and a second substrate during bonding.

A joining system according to one aspect of the present disclosure includes:
a surface modification device that modifies the bonding surface of the first substrate and the bonding surface of the second substrate;
a surface hydrophilization device that hydrophilizes the bonding surface of the modified first substrate and the bonding surface of the modified second substrate;
a bonding device for bonding the bonding surface of the hydrophilic first substrate and the hydrophilic bonding surface of the hydrophilic second substrate to face each other;
a cleaning device that cleans at least a non-bonded surface of the first substrate and the second substrate, which is held flat during bonding but is opposite to the bonded surface, before the bonding ;
The cleaning device includes a roughening section that roughens the non-bonding surface,
The surface roughening section roughens the non-bonded surfaces of the first substrate and the second substrate, which are deformed during bonding, except for the outer periphery thereof.

According to one aspect of the present disclosure, it is possible to suppress the generation of a gap between the first substrate and the second substrate during bonding.

FIG. 1 is a plan view showing a joining system according to one embodiment. FIG. 2 is a front view of a joining system according to one embodiment. FIG. 3 is a side view showing a polymerized substrate according to an embodiment separated into a first substrate and a second substrate. FIG. 4 is a diagram showing a manufacturing process of the second substrate according to one embodiment. FIG. 5 is a diagram showing a portion of the second substrate supported by the support portion according to one embodiment. FIG. 6 is a diagram showing a gap generated between a first substrate and a second substrate during bonding according to a conventional configuration. FIG. 7 is a plan view showing a cleaning device according to one embodiment. FIG. 8 is a front view showing the second holding part and the cleaning head part according to one embodiment. FIG. 9 is a perspective view showing a cleaning head section according to one embodiment. FIG. 10 is a diagram showing an inspection device according to one embodiment. FIG. 11 is a diagram showing a joining device according to one embodiment. FIG. 12 is a diagram showing the operation of the bonding device according to one embodiment. FIG. 13 is a flowchart showing the main steps of the joining method according to one embodiment. FIG. 14 is a flowchart showing processing of the second substrate based on the inspection results of the inspection apparatus according to the embodiment. FIG. 15 is a plan view showing a joining system according to a first modification. FIG. 16 is a front view showing a joining system according to a first modification. FIG. 17 is a diagram showing a surface hydrophilization device according to a first modification. FIG. 18 is a plan view showing a joining system according to a second modification. FIG. 19 is a front view showing a joining system according to a second modification. FIG. 20 is a flowchart showing the main steps of the joining method according to the second modification.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that in each drawing, the same or corresponding configurations are denoted by the same or corresponding symbols, and explanations may be omitted. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are directions perpendicular to each other. The X-axis direction and the Y-axis direction are horizontal, and the Z-axis direction is vertical.

FIG. 1 is a plan view showing a joining system according to one embodiment. FIG. 2 is a front view of a joining system according to one embodiment. In FIG. 2, illustration of the inspection device 32 and bonding device 41 shown in FIG. 1 is omitted in order to illustrate the positional relationship of the cleaning device 31, the surface modification device 33, and the surface hydrophilization device 35. FIG. 3 is a side view showing a polymerized substrate according to an embodiment separated into a first substrate and a second substrate.

The bonding system 1 shown in FIG. 1 forms a superposed substrate T by bonding a first substrate W1 and a second substrate W2. The first substrate W1 is a substrate in which a plurality of electronic circuits are formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. The second substrate W2 may be, for example, a substrate on which a plurality of electronic circuits are formed like the first substrate W1, or may be a bare wafer on which no electronic circuits are formed. The first substrate W1 and the second substrate W2 have approximately the same diameter.

Hereinafter, the first substrate W1 may be referred to as "upper wafer W1," the second substrate W2 may be referred to as "lower wafer W2," and the overlapping substrate T may be referred to as "overlapping wafer T." In the following, as shown in FIG. 3, among the plate surfaces of the upper wafer W1, the plate surface to be bonded to the lower wafer W2 will be referred to as a "bonding surface W1j", and the plate surface on the opposite side to the bonding surface W1j will be referred to as a "bonding surface W1j". is described as "non-bonded surface W1n". Further, among the plate surfaces of the lower wafer W2, the plate surface to be bonded to the upper wafer W1 is described as a "bonded surface W2j", and the plate surface on the opposite side to the bonded surface W2j is described as a "non-bonded surface W2n". .

FIG. 4 is a diagram showing a manufacturing process of the second substrate according to one embodiment. FIG. 4A is a diagram showing the second substrate during film formation according to an embodiment. FIG. 4(b) is a diagram illustrating the second substrate during cooling according to one embodiment. Note that the manufacturing process of the lower wafer W2 and the manufacturing process of the upper wafer W1 shown in FIG. 4 are the same, so the illustration of the manufacturing process of the upper wafer W1 is omitted.

The lower wafer W2 includes a base substrate W21 and a film W22 formed on the base substrate W21. The film W22 is formed by, for example, a CVD method. In the CVD method, a film W22 is formed on the surface of the base substrate W21 by supplying a gas serving as a raw material to the surface of the base substrate W21. At this time, the substrate holder 80 holds the base substrate W21 horizontally so that the bonding surface W2j of the lower wafer W2 faces upward.

The substrate holder 80 holds a plurality of base substrates W21 at intervals in the vertical direction. The substrate holder 80 has, for example, a plurality of (for example, four) column parts 81 extending in the vertical direction, and a plurality of support parts 82 arranged at intervals in the vertical direction on each of the plurality of column parts 81. . The support portion 82 supports the outer peripheral portion of the base substrate W21 from below.

The film W22 is formed at high temperature. At this time, a deposit 6 made of the same material as the film W22 is deposited on the support portion 82. Thereafter, when the substrate holder 80 and the lower wafer W2 are cooled, the lower wafer W2 contracts relative to the substrate holder 80. This is because, for example, the thermal expansion coefficient of silicon, which is the material of the lower wafer W2, is larger than that of quartz, which is the material of the substrate holder 80.

As the lower wafer W2 contracts relative to the substrate holder 80, the deposit 6 is peeled off from the support portion 82 as shown in FIG. It adheres as a deposit 7. The deposits 7 are formed at a portion supported by the support portion 82, and specifically, a plurality of deposits 7 are formed at intervals on the outer periphery of the non-bonding surface W2n.

FIG. 5 is a diagram showing a portion of the second substrate supported by the support portion according to one embodiment. Note that the portion W2s of the lower wafer W2 supported by the support portion 82 shown in FIG. Supported parts are omitted from illustration.

The deposits 7 may adhere to the four portions W2s corresponding to the four pillar portions 81. Note that the number of pillar portions 81 is not limited to four. For example, the number of pillar portions 81 may be three, and in this case, deposits may adhere to three portions W2s. Further, the substrate holder 80 may support the base substrate W21 vertically instead of horizontally.

FIG. 6 is a diagram showing a gap generated between a first substrate and a second substrate during bonding according to a conventional configuration. Although details will be described later, the upper wafer W1 and the lower wafer W2 are bonded gradually from the center toward the outer periphery (see FIGS. 11 and 12). During this time, the lower wafer W2 is held flat by the lower chuck 320, and the upper wafer W1 falls from the upper chuck 310 in stages from the center toward the outer periphery.

Conventionally, as shown in FIG. 6, deposits 7 have sometimes been caught between the outer circumference of the lower wafer W2 and the lower chuck 320. The deposit 7 locally displaces the lower wafer W2 upward, thereby locally reducing the distance between the lower wafer W2 and the upper wafer W1. As a result, the order of bonding is disrupted, and a gap 8 is generated as shown in FIG.

Note that during bonding, the upper wafer W1 may be held flat by the upper chuck 310 instead of the lower wafer W2. In this case as well, if the deposit 7 gets stuck between the outer circumference of the upper wafer W1 and the upper chuck 310, a gap 8 will be generated. The cause of the void 8 is that the wafer, which should be held flat during bonding, is distorted by the deposits 7.

The bonding system 1 of this embodiment includes a cleaning device 31 that cleans the non-bonding surface (for example, W2n) of the wafer (for example, the lower wafer W2) that is held flat and not deformed during bonding before bonding. Since deposits 7 that cause voids 8 during bonding can be removed before bonding, generation of voids 8 during bonding can be suppressed.

By the way, when the deposit 7 is brought into the bonding device 41, it can move inside the bonding device 41. For example, when the deposit 7 is brought into the bonding apparatus 41 together with the upper wafer W1, it may adhere to the upper chuck 310. Thereafter, the deposit 7 may fall from the upper chuck 310 to the lower chuck 320 and adhere to the lower chuck 320.

Therefore, the cleaning device 31 may clean the non-bonding surface (for example, W1n) of the wafer (for example, the upper wafer W1) that is deformed during bonding before bonding. Since it is possible to prevent the deposits 7 from being carried into the bonding device 41, the generation of the voids 8 can be further suppressed. Hereinafter, details of the joining system 1 of this embodiment will be explained.

As shown in FIG. 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 order of loading/unloading station 2 and processing station 3 along the positive direction of the X-axis. Further, the loading/unloading station 2 and the processing station 3 are integrally connected.

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. On each mounting plate 11, cassettes C1, C2, C3, and C4, each of which accommodates a plurality of substrates (for example, 25) in a horizontal state, are placed. For example, the cassette C1 accommodates the upper wafer W1, the cassette C2 accommodates the lower wafer W2, the cassette C3 accommodates the stacked wafer T, and the cassette C4 is one of the upper wafers W1 and the lower wafer W2 that is attached by the cleaning device 31. The kimono 7 that could not be removed is stored.

The transport area 20 is arranged adjacent to the mounting table 10 on the X-axis positive direction side. The transport area 20 is provided with a transport path 21 extending in the Y-axis direction and a transport device 22 movable along the transport path 21. The transport device 22 is movable not only in the Y-axis direction but also in the X-axis direction and can be rotated around the Z-axis, and transports the cassettes C1 to C4 placed on the mounting plate 11 and the processing station 3 to be described later. The upper wafer W1, the lower wafer W2, and the stacked wafer T are transferred to and from the third processing block G3.

Note that the number of cassettes C1 to C4 placed on the placement plate 11 is not limited to the number shown.

The processing station 3 is provided with a plurality of processing blocks, for example three processing blocks G1, G2, and G3, each equipped with various devices. For example, a first processing block G1 is provided on the back side of the processing station 3 (positive side of the Y-axis in FIG. 1), and a second processing block G1 is provided on the front side of the processing station 3 (negative side of the Y-axis in FIG. 1). A processing block G2 is provided. Furthermore, a third processing block G3 is provided on the loading/unloading station 2 side of the processing station 3 (on the X-axis negative direction side in FIG. 1).

Further, as shown in FIG. 1, a transport area 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 transport device 61 is arranged in the transport area 60 . The transport device 61 has a transport arm that is movable, for example, in the vertical direction, horizontal direction, and around a vertical axis. The transport device 61 moves within the transport area 60 and transfers the upper wafer W1, the lower wafer W2, and The polymerized wafer T is transported.

A cleaning device 31, a surface modification device 33, and a surface hydrophilization device 35 are arranged in the first processing block G1. As shown in FIG. 1, the cleaning device 31 is arranged, for example, on the negative side of the X-axis of the surface modification device 33 and the surface hydrophilization device 35. The surface hydrophilization device 35 is placed, for example, on the surface modification device 33, as shown in FIG. Note that the type and arrangement of devices arranged in the first processing block G1 are not particularly limited. For example, the cleaning device 31 may be arranged in the second processing block G2 or the third processing block G3 instead of the first processing block G1. Furthermore, the surface hydrophilization device 35 may be placed below the surface modification device 33.

FIG. 7 is a plan view showing a cleaning device according to one embodiment. FIG. 8 is a front view showing the second holding part and the cleaning head part according to one embodiment. FIG. 8A is a front view showing a state in which the polishing section and the second substrate according to one embodiment are separated. FIG. 8(b) is a front view showing a state in which the polishing section and the second substrate are in contact with each other according to one embodiment. In FIG. 8, illustration of the first holding portion shown in FIG. 7 is omitted. FIG. 9 is a perspective view showing a cleaning head section according to one embodiment. In FIGS. 7 to 9, the x-axis direction, y-axis direction, and z-axis direction are directions perpendicular to each other. The x-axis direction and the y-axis direction are horizontal, and the z-axis direction is vertical. Therefore, the Z-axis direction coincides with the Z-axis direction. One of the x-axis direction and the y-axis direction (for example, the x-axis direction) coincides with the X-axis direction, and the remaining one (for example, the y-axis direction) coincides with the Y-axis direction.

The cleaning device 31 cleans the non-bonding surface W2n of the lower wafer W2 before bonding by the bonding device 41. Similarly, the cleaning device 31 cleans the non-bonding surface W1n of the upper wafer W1 before bonding by the bonding device 41. Hereinafter, the cleaning of the non-bonding surface W2n of the lower wafer W2 will be representatively explained, and the explanation of the cleaning of the non-bonding surface W1n of the upper wafer W1 will be omitted.

As shown in FIG. 7 or 8, the cleaning device 31 includes a first holding section 110, a first driving section 115, a second holding section 120, a second driving section 125, a cleaning head section 130, and a cleaning head section 130. It has a third drive section 135 and a fourth drive section 136.

The first holding unit 110 holds the lower wafer W2 horizontally from below with the bonding surface W2j of the lower wafer W2 facing upward. The first holding portion 110 holds the outer peripheral portion of the non-bonding surface W2n of the lower wafer W2. Since the central part of the non-bonding surface W2n of the lower wafer W2 is not held by the first holding part 110, it can be scrubbed by the cleaning head part 130.

The first holding portion 110 is formed, for example, in a parallel cross shape. The first holding part 110 includes a pair of rod-shaped suction parts 111 and 112 and a pair of rod-shaped connecting parts 113 and 114. A pair of suction parts 111 and 112 extend in the x-axis direction. The pair of adsorption units 111 and 112 are connected to a vacuum pump via piping. When the control device 70 operates the vacuum pump, the pair of suction parts 111 and 112 suction the lower wafer W2 from below. The pair of connecting parts 113 and 114 extend in the y-axis direction and connect the pair of adsorption parts 111 and 112 at intervals in the y-axis direction.

The first drive section 115 moves the first holding section 110. For example, the first drive section 115 moves the first holding section 110 in the x-axis direction. Further, the first driving section 115 moves the first holding section 110 in the z-axis direction, for example.

The second holding section 120 alternates with the first holding section 110 and holds the lower wafer W2 horizontally from below with the bonding surface W2j of the lower wafer W2 facing upward. The second holding section 120, unlike the first holding section 110, holds the central portion of the non-bonding surface W2n of the lower wafer W2. Since the outer peripheral portion of the non-bonding surface W2n of the lower wafer W2 is not held by the second holding section 120, it can be scrubbed by the cleaning head section 130.

The second holding part 120 is formed, for example, in a disc shape. The second holding part 120 is connected to a vacuum pump via piping. When the control device 70 operates the vacuum pump, the second holding section 120 sucks the lower wafer W2 from below.

The second driving section 125 rotates the second holding section 120 around the z-axis. Further, the second driving section 125 moves the second holding section 120 in the z-axis direction.

The cleaning head section 130 scrubs the non-bonding surface W2n of the lower wafer W2. The cleaning head section 130 supplies a cleaning liquid such as water toward the non-bonding surface W2n of the lower wafer W2 while in contact with the non-bonding surface W2n of the lower wafer W2.

The cleaning head section 130 includes, for example, a disk-shaped base section 131, a cylindrical sponge section 132, and a cylindrical polishing section 133. The sponge portion 132 is made of polyvinyl alcohol (PVA), for example. The sponge portion 132 is fixed to the base portion 131, and while rotating together with the base portion 131, scrubs the non-bonding surface W2n of the lower wafer W2 as shown in FIGS. 8(a) and 8(b).

The sponge portion 132 is vertically sandwiched between the lower wafer W2 held by the second holding portion 120 and the base portion 131. When the sponge part 132 is compressed in the vertical direction as shown in FIG. 8(b) due to the lowering of the second holding part 120 or the raising of the base part 131, the polishing part 133 contacts the non-bonding surface W2n of the lower wafer W2. Contact.

For example, the polishing part 133 is arranged concentrically with the sponge part 132 so as to surround the sponge part 132. The polishing section 133 is fixed to the base section 131 and polishes the non-bonding surface W2n of the lower wafer W2 while rotating together with the base section 131. The deposits 7 firmly attached to the non-bonding surface W2n can be scraped off, and the non-bonding surface W2n can be smoothed. Note that the polishing section 133 may also serve as a roughening section that roughens the non-bonding surface W2n. The roughening section shaves off the originally flat portion of the non-bonding surface W2n to roughen the non-bonding surface W2n. Note that the polishing section 133 and the roughening section may be separate, or only one of them may be installed.

The polishing section 133 includes, for example, a polishing sheet 134 containing diamond abrasive grains. A plurality of polishing sheets 134 are arranged at intervals in the circumferential direction. Since diamond abrasive grains are hard, they can efficiently scrape off firmly attached deposits 7. Note that silicon carbide abrasive grains, alumina abrasive grains, equiaxed boron nitride abrasive grains, etc. may be used instead of diamond abrasive grains. The polishing sheet 134 may also serve as a roughening sheet that roughens the non-bonding surface W2n. Note that the polishing sheet 134 and the roughening sheet may be separate, or only one of them may be installed.

The third drive section 135 rotates the cleaning head section 130 around the z-axis. Further, the fourth drive section 136 moves the cleaning head section 130 in the y-axis direction.

Next, the operation of the cleaning device 31 will be explained. The cleaning device 31 performs the following operations under the control of the control device 70.

First, the cleaning device 31 scrubs the center portion of the lower wafer W2 with the cleaning head portion 130 while holding the outer peripheral portion of the lower wafer W2 with the first holding portion 110. The cleaning device 31 may perform scrubbing using only the sponge portion 132 while rotating the base portion 131, or may scrub using both the sponge portion 132 and the polishing portion 133. The cleaning device 31 alternately moves the first holding section 110 in the x-axis direction and the cleaning head section 130 in the y-axis direction, thereby cleaning the non-bonding surface W2n of the lower wafer W2. One area A1 (area indicated by dots in FIG. 7) is cleaned. The first area A1 has a rectangular shape.

Next, the cleaning device 31 scrubs the outer peripheral portion of the lower wafer W2 with the cleaning head unit 130 while holding the center portion of the lower wafer W2 with the second holding unit 120. The cleaning device 31 may perform scrubbing using only the sponge portion 132 while rotating the base portion 131, or may scrub using both the sponge portion 132 and the polishing portion 133. The cleaning device 31 cleans the second region A2 of the non-bonding surface W2n of the lower wafer W2 by moving the cleaning head section 130 in the y-axis direction while rotating the second holding section 120 around the z-axis. The second area A2 is an area outside the first area A1 and surrounds the first area A1.

Note that the order of cleaning may be reversed. Specifically, the cleaning device 31 first scrubs the outer peripheral part of the lower wafer W2 with the cleaning head part 130 while holding the center part of the lower wafer W2 with the second holding part 120, and then scrubs the outer peripheral part of the lower wafer W2. The center portion of the lower wafer W2 may be scrubbed by the cleaning head portion 130 while the lower wafer W2 is held by the first holding portion 110.

The lower wafer W2 cleaned by the cleaning device 31 is transported to the inspection device 32 by the transport device 61. The inspection device 32 will be described later. The lower wafer W2 is inspected by the inspection device 32 and then transferred to the surface modification device 33 by the transfer device 61. Note that the inspection device 32 may not be provided. In that case, the lower wafer W2 cleaned by the cleaning device 31 is transported to the surface modification device 33 by the transport device 61.

The surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. For example, the surface modification device 33 modifies the bonding surfaces W1j, W2j by cutting the SiO ₂ bonds at the bonding surfaces W1j, W2j to form a single bond of SiO, so that the bonding surfaces W1j, W2j are easily made hydrophilic thereafter. .

In the surface modification device 33, oxygen gas, which is a processing gas, is excited, turned into plasma, and ionized, for example, under a reduced pressure atmosphere. Then, by irradiating the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 with such oxygen ions, the bonding surfaces W1j and W2j are plasma-treated and modified. The processing gas is not limited to oxygen gas, and may be, for example, nitrogen gas.

The surface hydrophilization device 35 hydrophilizes the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 using, for example, pure water. The surface hydrophilic device 35 also has the role of cleaning the bonding surfaces W1j and W2j. In the surface hydrophilization device 35, 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 a spin chuck, for example. As a result, the pure water supplied onto the upper wafer W1 or the lower wafer W2 diffuses over the bonding surfaces W1j, W2j of the upper wafer W1 or the lower wafer W2, making the bonding surfaces W1j, W2j hydrophilic.

In the second processing block G2, an inspection device 32 and a bonding device 41 are arranged. As shown in FIG. 1, the inspection device 32 is arranged, for example, on the negative side of the X-axis of the bonding device 41. Note that the type and arrangement of devices arranged in the second processing block G2 are not particularly limited. For example, the inspection device 32 may be placed in the first processing block G1 or the third processing block G3 instead of the second processing block G2.

FIG. 10 is a diagram showing an inspection device according to one embodiment. The inspection device 32 inspects the presence or absence of deposits 7 adhering to the non-bonding surface W2n of the lower wafer W2 before bonding by the bonding device 41. Similarly, the inspection device 32 inspects the presence or absence of deposits 7 adhering to the non-bonding surface W1n of the upper wafer W1 before bonding by the bonding device 41. Hereinafter, the inspection of the non-bonding surface W2n of the lower wafer W2 will be representatively explained, and the explanation of the inspection of the non-bonding surface W1n of the upper wafer W1 will be omitted. The inspection device 32 includes a holding section 210, a guide section 220, an imaging section 230, an illumination section 240, a mirror section 250, and an image processing section 260.

The holding unit 210 holds the lower wafer W2 horizontally from below with the bonding surface W2j of the lower wafer W2 facing upward. The holding part 210 moves horizontally along the guide part 220. The imaging unit 230 images the non-bonding surface W2n of the lower wafer W2. The range to be imaged is a linear range perpendicular to the moving direction of the holding section 210. The imaging unit 230 includes, for example, an imaging device such as a CCD or a CMOS. The illumination unit 240 irradiates the non-bonding surface W2n of the lower wafer W2 with light. The light irradiation range includes at least the imaging range. The mirror section 250 reflects the light reflected by the non-bonding surface W2n toward the imaging section 230.

By moving the holding section 210 along the guide section 220, the imaging section 230 can image the entire non-bonding surface W2n. The imaging unit 230 transmits the captured image to the image processing unit 260. The image processing unit 260 is configured with a computer or the like, and determines the presence or absence of the deposit 7 adhering to the non-bonding surface W2n by processing the image captured by the imaging unit 230. Note that although the image processing section 260 is provided separately from the control device 70, it may be provided as a part of the control device 70.

As described above, the inspection device 32 inspects the presence or absence of the deposits 7 adhering to the non-bonding surface W2n of the lower wafer W2 before bonding, so that the deposits 7 can be prevented from being brought into the bonding device 41. . The lower wafer W2 with the deposit 7 is cleaned by the cleaning device 31 and then inspected by the inspection device 32 again. Alternatively, the lower wafer W2 with the deposit 7 is collected into the cassette C4. On the other hand, the lower wafer W2 without any deposits 7 is transported to the surface modification device 33 by the transport device 61.

Note that the inspection device 32 does not have to inspect the entire non-bonding surface W2n of the lower wafer W2. The inspection device 32 may inspect at least the outer peripheral portion of the non-bonded surface W2n. This is because if the deposit 7 is derived from the deposit 6 of the same material as the film W22, it tends to adhere to the outer periphery of the non-bonding surface W2n.

FIG. 11 is a diagram showing a joining device according to one embodiment. FIG. 12 is a diagram showing the operation of the bonding device according to one embodiment. FIG. 12A is a diagram showing a state when the upper chuck shown in FIG. 11 releases the central part of the upper wafer. FIG. 12(b) is a diagram showing a state when the upper chuck shown in FIG. 12(a) releases the outer peripheral portion of the upper wafer.

As shown in FIG. 11, the bonding device 41 faces the bonding surface W1j of the hydrophilic upper wafer W1 and the hydrophilic bonding surface W2j of the hydrophilic lower wafer W2, and as shown in FIG. The lower wafer W2 is bonded. The bonding device 41 includes, for example, an upper chuck 310, a lower chuck 320, and a pressing section 330.

The upper chuck 310 horizontally holds the upper wafer W1 from above with the bonding surface W1j of the upper wafer W1 facing downward. The upper chuck 310 corresponds to a first substrate holder described in the claims. The upper chuck 310 is, for example, a pin chuck, and includes a first frame portion 311 and a first pin portion 312. The first frame portion 311 is formed in an annular shape and supports the outer peripheral portion of the non-bonding surface W1n of the upper wafer W1. The first pin portions 312 are distributed inside the first frame portion 311 and support the non-bonding surface W1n of the upper wafer W1.

The upper chuck 310 is connected to a vacuum pump via piping. When the control device 70 operates the vacuum pump, the upper chuck 310 attracts the upper wafer W1. The upper chuck 310 has a first partition portion 313 that partitions a plurality of regions in order to independently control the suction pressure of the upper wafer W1 in the plurality of regions. The first partition portion 313 is formed inside the first frame portion 311 in a concentric shape with the first frame portion 311 . The degree of vacuum can be independently controlled on the inside and outside of the first partition portion 313, and suction and release thereof can be independently controlled.

The lower chuck 320 horizontally holds the lower wafer W2 from below with the bonding surface W2j of the lower wafer W2 facing upward. The lower chuck 320 corresponds to a second substrate holder described in the claims. The lower chuck 320 is, for example, a pin chuck, and includes a second frame portion 321 and a second pin portion 322. The second frame portion 321 is formed in an annular shape and supports the outer peripheral portion of the non-bonding surface W2n of the lower wafer W2. The second pin portions 322 are distributed inside the second frame portion 321 and support the non-bonding surface W2n of the lower wafer W2.

The lower chuck 320 is connected to a vacuum pump via piping. When the control device 70 operates the vacuum pump, the lower chuck 320 attracts the lower wafer W2. The lower chuck 320 has a second partition portion 323 that partitions a plurality of regions in order to independently control the suction pressure of the lower wafer W2 in the plurality of regions. The second partition portion 323 is formed inside the second frame portion 321 in a concentric shape with the second frame portion 321 . Since the degree of vacuum can be independently controlled on the inside and outside of the second partition portion 323, and the suction pressure can be independently controlled, the distortion of the lower wafer W2 can be controlled.

The pressing section 330 presses the center of the upper wafer W1 from above. The pressing section 330 includes a pressing pin 331, an actuator 332, and a lifting mechanism 333. The pressing pin 331 is arranged in a through hole that vertically passes through the center of the upper chuck 310. The actuator 332 presses the pressing pin 331 downward with a constant force using air supplied from, for example, an electropneumatic regulator. The lifting mechanism 333 is fixed to the upper chuck 310 and moves the actuator 332 up and down.

Next, the operation of the bonding device 41 will be explained. The bonding device 41 performs the following operations under the control of the control device 70.

First, as shown in FIG. 11, the bonding device 41 uses the upper chuck 310 to suck the entire upper wafer W1 in the radial direction, and the lower chuck 320 to suck the entire lower wafer W2 in the radial direction. The bonding device 41 includes a lift pin (not shown) that supports the center portion of the lower wafer W2 and a drive unit that moves the lift pin up and down. The lift pin protrudes above the lower chuck 320 to receive the lower wafer W2, and then descends to transfer the lower wafer W2 to the lower chuck 320. Since the lift pins do not support the outer peripheral portion of the lower wafer W2, the lower wafer W2 is placed on the lower chuck 320 in an upwardly curved state. If the non-bonding surface W2n of the lower wafer W2 is roughened in advance using the cleaning device 31, the contact area between the lower wafer W2 and the lower chuck 320 can be reduced, and the frictional resistance between the lower wafer W2 and the lower chuck 320 can be reduced. Therefore, when the lower wafer W2 is attracted to the lower chuck 320, the lower wafer W2 can be smoothly transferred without being distorted. The distance S between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 is adjusted to a predetermined distance, for example, 50 μm to 200 μm.

Next, as shown in FIG. 12A, the bonding device 41 releases the adsorption of the center of the upper wafer W1, and presses the center of the upper wafer W1 from above using the pressing section 330. As a result, the center of the upper wafer W1 comes into contact with the center of the lower wafer W2, and bonding begins. After that, a bonding wave is generated that gradually joins the upper wafer W1 and the lower wafer W2 from the center toward the outer periphery. If the non-bonding surface W1n of the upper wafer W1 is roughened in advance using the cleaning device 31, the contact area between the upper wafer W1 and the upper chuck 310 can be reduced, and the force required to separate the upper wafer W1 and the upper chuck 310 can be reduced. can. Therefore, the upper wafer W1 and the upper chuck 310 can be smoothly separated from the center of the upper wafer W1 toward the outer periphery.

Here, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified, van der Waals force (intermolecular force) is generated between the bonding surfaces W1j and W2j, and the bonding Surfaces W1j and W2j are joined together. Furthermore, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are each made hydrophilic, the hydrophilic groups between the bonding surfaces W1j and W2j form hydrogen bonds, and the bonding surfaces W1j and W2j are firmly bonded to each other. be done.

Next, as shown in FIG. 12(b), the bonding device 41 adsorbs the outer periphery of the upper wafer W1 while pressing the center of the upper wafer W1 against the center of the lower wafer W2 using the pressing unit 330. unlock. If the slippage of the outer periphery of the upper wafer W1 can be suppressed until the outer periphery of the upper wafer W1 is released from suction, the positional shift between the upper wafer W1 and the lower wafer W2 can be suppressed. Therefore, the cleaning device 31 does not roughen the outer periphery of the non-bonding surface W1n of the upper wafer W1 in order to suppress slipping on the outer periphery of the upper wafer W1. The region that is not roughened includes, for example, at least a region within 10 mm from the outer periphery of the non-bonding surface W1n. Note that the area that is not roughened does not need to be rubbed with the roughened part, and may be rubbed with the sponge part 132. The cleaning device 31 roughens the non-bonding surface W1n except for the outer peripheral portion thereof. Since the outer periphery of the non-bonding surface W1n is not roughened, the adhesion between the outer periphery of the upper wafer W1 and the upper chuck 310 can be improved. Improving adhesion leads to an increase in frictional resistance and a reduction in vacuum leakage. As a result, it is possible to suppress the slippage of the outer peripheral portion of the upper wafer W1, and to reduce the positional deviation between the upper wafer W1 and the lower wafer W2. When the outer periphery of the upper wafer W1 is released from suction, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into full contact, and the upper wafer W1 and the lower wafer W2 are bonded. After that, the bonding device 41 raises the press pin 331 to the upper chuck 310 and releases the lower wafer W2 from being attracted.

As shown in FIG. 2, transition devices 50 and 51 are arranged in the third processing block G3. The transition device 50 temporarily stores the upper wafer W1 and the lower wafer W2. The transition device 51 temporarily stores the polymerized wafer T. The plurality of transition devices 50, 51 are stacked vertically. Note that the type and arrangement of devices arranged in the third processing block G3 are not particularly limited.

Further, as shown in FIG. 1, the joining system 1 includes a control device 70. The control device 70 is composed of, for example, a computer, and includes a CPU (Central Processing Unit) 71 and a storage medium 72 such as a memory. The storage medium 72 stores programs that control various processes executed in the joining system 1. The control device 70 controls the operation of the joining system 1 by causing the CPU 71 to execute a program stored in the storage medium 72. Further, the control device 70 includes an input interface 73 and an output interface 74. The control device 70 receives signals from the outside through an input interface 73, and transmits signals to the outside through an output interface 74.

The program for the control device 70 is, for example, stored in a computer-readable storage medium and installed from the storage medium. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnetic optical disks (MO), and memory cards. Note that the program for the control device 70 may be downloaded from a server via the Internet and installed.

FIG. 13 is a flowchart showing the main steps of the joining method according to one embodiment. Note that the various steps shown in FIG. 13 are executed under the control of the control device 70.

First, a cassette C1 containing a plurality of upper wafers W1, a cassette C2 containing a plurality of lower wafers W2, and empty cassettes C3 and C4 are placed on a predetermined mounting plate 11 of the loading/unloading station 2. Ru.

Next, the transport device 22 takes out the upper wafer W1 from the cassette C1 and transports it to the transition device 50. Subsequently, the transport device 61 receives the upper wafer W1 from the transition device 50 and transports it to the cleaning device 31.

Next, the cleaning device 31 cleans the non-bonding surface W1n of the upper wafer W1 (S101). The cleaning device 31 cleans at least the outer peripheral portion of the non-bonding surface W1n. This is because, if the deposit 7 is derived from the deposit 6 of the same material as the film W22, it tends to adhere to the outer periphery of the non-bonding surface W1n. The firmly attached deposits 7 can also be scraped off by the polishing section 133. Thereafter, the transport device 61 receives the upper wafer W1 from the cleaning device 31 and transports it to the inspection device 32.

Next, the inspection device 32 inspects the presence or absence of deposits 7 adhering to the non-bonding surface W1n of the upper wafer W1 (S102). The upper wafer W1 with the deposit 7 is cleaned by the cleaning device 31 again, and then inspected by the inspection device 32 again. Alternatively, the lower wafer W2 with the deposit 7 is collected into the cassette C4. On the other hand, the lower wafer W2 without any deposits 7 is transported to the surface modification device 33 by the transport device 61.

Next, the surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 (S103). In the surface modification device 33, oxygen gas, which is a processing gas, is excited, turned into plasma, and ionized in a reduced pressure atmosphere. These oxygen ions are irradiated onto the bonding surface W1j of the upper wafer W1, and the bonding surface W1j is subjected to plasma treatment. This modifies the bonding surface W1j of the upper wafer W1. Thereafter, the transport device 61 transports the upper wafer W1 from the surface modification device 33 to the surface hydrophilization device 35.

Next, the surface hydrophilization device 35 hydrophilizes the bonding surface W1j of the upper wafer W1 (S104). The surface hydrophilization device 35 supplies pure water onto the upper wafer W1 while rotating the upper wafer W1 held by the spin chuck. Then, the supplied pure water diffuses over the bonding surface W1j of the upper wafer W1, and hydroxyl groups (silanol groups) adhere to the bonding surface W1j of the upper wafer W1 that has been modified in the surface modification device 33, resulting in the bonding surface W1j being modified by the surface modification device 33. W1j is made hydrophilic. Further, the bonding surface W1j of the upper wafer W1 is cleaned by the pure water used to make the bonding surface W1j hydrophilic. Thereafter, the transport device 61 transports the upper wafer W1 to the bonding device 41.

The bonding device 41 turns the upper wafer W1 upside down and directs the bonding surface W1j of the upper wafer W1 downward (S105). Note that although the reversing device for reversing the upper wafer W1 upside down is provided inside the bonding device 41 in this embodiment, it may be provided outside the bonding device 41. While the upper wafer W1 is being processed (S101 to S105 above), the lower wafer W2 is being processed (S106 to S109 below).

First, the transport device 22 takes out the lower wafer W2 from the cassette C2 and transports it to the transition device 50. Subsequently, the transport device 61 receives the lower wafer W2 from the transition device 50 and transports it to the cleaning device 31.

Next, the cleaning device 31 cleans the non-bonding surface W2n of the lower wafer W2 (S106). The cleaning device 31 cleans at least the outer peripheral portion of the non-bonding surface W2n. This is because if the deposit 7 is derived from the deposit 6 of the same material as the film W22, it tends to adhere to the outer periphery of the non-bonding surface W2n. The firmly attached deposits 7 can also be scraped off by the polishing section 133. Thereafter, the transport device 61 receives the lower wafer W2 from the cleaning device 31 and transports it to the inspection device 32.

Next, the inspection device 32 inspects the presence or absence of deposits 7 adhering to the non-bonding surface W2n of the lower wafer W2 (S107). The lower wafer W2 with the deposit 7 is cleaned by the cleaning device 31 again, and then inspected by the inspection device 32 again. Alternatively, the lower wafer W2 with the deposit 7 is collected into the cassette C4. On the other hand, the lower wafer W2 without any deposits 7 is transported to the surface modification device 33 by the transport device 61.

Next, the surface modification device 33 modifies the bonding surface W2j of the lower wafer W2 (S108). The surface modification of the joint surface W2j (S108) is performed in the same manner as the surface modification of the joint surface W1j (S103). Thereafter, the transport device 61 transports the lower wafer W2 from the surface modification device 33 to the surface hydrophilization device 35.

Next, the surface hydrophilization device 35 hydrophilizes the bonding surface W2j of the lower wafer W2 (S109). The surface hydrophilization of the joint surface W2j (S109) is performed in the same manner as the surface hydrophilization of the joint surface W1j (S104). Thereafter, the transport device 61 transports the lower wafer W2 to the bonding device 41.

Next, the bonding device 41 bonds the upper wafer W1 and the lower wafer W2 with the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 facing each other (S110). Since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified in advance, van der Waals force (intermolecular force) is generated between the bonding surfaces W1j, W2j, and the bonding surfaces W1j, W2j are joined together. In addition, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are each made hydrophilic in advance, the hydrophilic groups between the bonding surfaces W1j and W2j form hydrogen bonds, and the bonding surfaces W1j and W2j are strongly bonded to each other. is joined to.

Thereafter, the transport device 61 transports the superposed wafer T to the transition device 51. Thereafter, the transport device 22 receives the superposed wafer T from the transition device 51 and transports it to the cassette C3. In this way, the series of processing ends.

By the way, the control device 70 transports the upper wafer W1 and the lower wafer W2 to the cleaning device 31 and the inspection device 32 in this order. First, cleaning is performed in the cleaning device 31, so that the deposits 7 can be prevented from being brought into the inspection device 32.

Note that the control device 70 may transport the upper wafer W1 and the lower wafer W2 to the inspection device 32 and the cleaning device 31 in this order. In this case, since the inspection device 32 first performs the inspection, it is possible to prevent the cleaning device 31 from cleaning wafers without deposits 7 in vain.

The control device 70 prohibits the items for which the inspection device 32 has tested that there is no deposit 7 from being transported to the cleaning device 31 . It is possible to prevent wasteful cleaning of wafers without deposits 7 by the cleaning device 31.

FIG. 14 is a flowchart showing processing of the second substrate based on the inspection results of the inspection apparatus according to the embodiment. Note that the processing of the lower wafer W2 and the processing of the upper wafer W1 shown in FIG. 14 are performed in the same way, so the processing of the upper wafer W1 is omitted from illustration. The processing shown in FIG. 14 is performed under the control of the control device 70.

First, the inspection device 32 inspects the presence or absence of deposits 7 adhering to the non-bonding surface W2n of the lower wafer W2 (S201). Next, the control device 70 checks the test results of the test device 32 (S202).

If there is no deposit 7 (S202, NO), the deposit 7 will not be brought into the bonding device 41. Therefore, the control device 70 transports the lower wafer W2 to the surface modification device 33 without transporting the lower wafer W2 to the cleaning device 31 using the transport device 61 (S203).

On the other hand, if there is any deposit 7 (S202, YES), the deposit 7 will be brought into the bonding device 41 if left as is. Therefore, the control device 70 first checks whether the number of times the lower wafer W2 has been cleaned up to the inspection (S201) is less than N times (N is a predetermined integer of 1 or more) (S204). ). N is determined in advance according to the cleaning power of the cleaning device 31.

If the number of cleanings of the lower wafer W2 is N times or more (S204), there is almost no possibility that the cleaning device 31 can remove the deposits 7. Therefore, in this case, the control device 70 transports the lower wafer W2 to the cassette C4 using the transport devices 61 and 22 (S205).

On the other hand, if the number of cleanings of the lower wafer W2 is less than N times, there remains a possibility that the deposit 7 can be removed by the cleaning device 31. Therefore, in this case, the control device 70 transports the lower wafer W2 to the cleaning device 31 using the transport device 61 (S206).

Thereafter, the cleaning device 31 cleans the non-bonding surface W2n of the lower wafer W2. Subsequently, the control device 70 transports the lower wafer W2 to the inspection device 32 using the transport device 61. After that, the process shown in FIG. 14 is performed again.

As described above, the control device 70 transports the lower wafer W2, for which the inspection device 32 has determined that the deposit 7 is present, to the cleaning device 31 using the transport device 61. Since the deposits 7 can be removed by the cleaning device 31, the number of discarded lower wafers W2 can be reduced.

The control device 70 transports the lower wafer W2, for which the inspection device 32 has determined that the deposit 7 is present, to the cleaning device 31 using the transportation device 61, and then transports it to the inspection device 32 again. It is possible to check with the inspection device 32 whether the deposits 7 have been removed by the cleaning device 31, and it is possible to reliably prevent the deposits 7 from being carried into the bonding device 41.

The control device 70 transports the lower wafer W2, which has been tested by the testing device 32 to be free of deposits 7, to the surface modification device 33 without being transported to the cleaning device 31 by the transport device 61. Since the deposits 7 are not brought into the surface modification device 33, surface hydrophilization device 35, and bonding device 41, contamination of these devices 33, 35, and 41 can be suppressed.

As shown in FIG. 13, the control device 70 performs cleaning (S106) and inspection (S107) of the lower wafer W2 before surface modification (S108), surface hydrophilization (S109), and bonding (S110). Since the treatment of the bonded surface W2j is started after finishing the treatment of the non-bonded surface W2n, the elapsed time from surface modification (S108) to bonding (S110) can be shortened, and the surface modification ( S108) and surface hydrophilization (S109) can be prevented from being lost.

Note that cleaning (S106) and inspection (S107) of the lower wafer W2 only need to be performed before bonding (S110), and may be performed between surface modification (S108) and surface hydrophilization (S109). Alternatively, it may be performed between surface hydrophilization (S109) and bonding (S110). In these cases as well, the deposits 7 can be prevented from being brought into the bonding device 41, and the generation of voids 8 can be prevented.

Further, the cleaning of the lower wafer W2 (S106) may be performed simultaneously with the surface hydrophilization (S109), as described later. In this case, the cleaning device 31 has a built-in cleaning section that is built into the surface hydrophilization device 35 .

FIG. 15 is a plan view showing a joining system according to a first modification. FIG. 16 is a front view showing a joining system according to a first modification. In FIG. 16, illustration of the bonding device 41 shown in FIG. 15 is omitted in order to illustrate the positional relationship between the surface modification device 33 and the surface hydrophilization device 35. FIG. 17 is a diagram showing a surface hydrophilization device according to a first modification.

The cleaning device 31 of this modified example includes a built-in cleaning head section 140 that is incorporated into the surface hydrophilic device 35 . By simply incorporating the built-in cleaning head section 140 into the existing device 35, it is possible to prevent the deposits 7 from being brought into the bonding device 41, thereby suppressing the increase in size of the bonding system 1. Hereinafter, differences between this modification and the above embodiment will be mainly explained.

The surface hydrophilization device 35 includes, for example, a processing container 410, a spin chuck 420, and a nozzle 430. The spin chuck 420 horizontally holds the upper wafer W1 from below inside the processing container 410 with the bonding surface W1j of the upper wafer W1 facing upward. Similarly, the spin chuck 420 horizontally holds the lower wafer W2 from below inside the processing container 410 with the bonding surface W2j of the lower wafer W2 facing upward.

The nozzle 430 supplies water such as DIW (deionized water) to the joint surfaces W1j and W2j from above. The nozzle 430 may be a two-fluid nozzle that discharges a mixture of water and gas. The nozzle 430 supplies water to the center of the joint surfaces W1j and W2j that rotate together with the spin chuck 420. The supplied water wets and spreads over the entire joint surfaces W1j and W2j due to centrifugal force. The nozzle 430 may move in the radial direction of the joint surfaces W1j and W2j.

Incidentally, the spin chuck 420 holds the central portions of the non-bonded surfaces W1n and W2n. Since the outer peripheries of the non-bonding surfaces W1n and W2n are not held by the spin chuck 420, they can be scrubbed by the built-in cleaning head section 140.

The built-in cleaning head section 140 scrubs the non-bonding surfaces W1n and W2n similarly to the cleaning head section 130. The built-in cleaning head section 140 supplies cleaning liquid such as water toward the non-bonding surfaces W1n and W2n while in contact with the non-bonding surfaces W1n and W2n.

Like the cleaning head section 130, the built-in cleaning head section 140 includes, for example, a disk-shaped base section 141, a cylindrical sponge section 142, and a cylindrical polishing section 143. The base portion 141, the sponge portion 142, and the polishing portion 143 are configured in the same manner as the base portion 131, the sponge portion 132, and the polishing portion 133 of the above embodiment, so a description thereof will be omitted. Note that, like the polishing section 133, the polishing section 143 may also serve as a roughening section that roughens the non-bonding surface W2n. Furthermore, the polishing section 143 and the surface roughening section may be separate, or only one of them may be installed.

Further, the cleaning device 31 of this modification may further include an outer periphery cleaning section 150 that is incorporated inside the surface hydrophilization device 35. The outer periphery cleaning section 150 scrubs the outer periphery of the upper wafer W1 or the outer periphery of the lower wafer W2. The outer periphery cleaning section 150 is, for example, a sponge, but may also be a brush. Adhesive matter can be removed from the outer periphery of the upper wafer W1 or the outer periphery of the lower wafer W2.

FIG. 18 is a plan view showing a joining system according to a second modification. FIG. 19 is a front view showing a joining system according to a second modification. In FIG. 19, illustration of the bonding device 41 shown in FIG. 18 is omitted in order to illustrate the positional relationship between the surface modification device 33 and the surface hydrophilization device 35. The arrangement of the devices in the first processing block G1 is different between this modification and the above-described embodiments. Hereinafter, differences between this modified example and the above-described embodiments will be mainly explained.

As shown in FIG. 19, a cleaning device 31, a surface modification device 33, and a surface hydrophilization device 35 are arranged in the first processing block G1. The cleaning device 31 and the surface hydrophilization device 35 are arranged, for example, on the surface modification device 33. Note that the type and arrangement of the devices in the first processing block G1 are not particularly limited. For example, the cleaning device 31 and the surface hydrophilization device 35 may be arranged below the surface modification device 33.

As shown in FIG. 19, the cleaning device 31 and the surface hydrophilic device 35 are installed separately and lined up in the X-axis direction, but the technology of the present disclosure is not limited thereto. As shown in FIG. 17, the cleaning device 31 may be incorporated inside the surface hydrophilic device 35, in which case the surface hydrophilic device 35 for the upper wafer W1 and the surface hydrophilic device 35 for the lower wafer W2 are combined. They may be installed separately and lined up in the X-axis direction. The number of surface hydrophilic devices 35 can be increased, and throughput can be improved.

Note that the arrangement of the surface modification device 33 is also similar to the arrangement of the surface hydrophilization device 35. That is, the surface modification device 33 for the upper wafer W1 and the surface modification device 33 for the lower wafer W2 may be installed separately.

FIG. 20 is a flowchart showing the main steps of the joining method according to the second modification. The various steps shown in FIG. 20 are executed under the control of the control device 70. The differences between FIG. 20 and FIG. 13 will be mainly described below.

As shown in FIG. 20, cleaning of the upper wafer W1 (S101) may be performed after making the surface of the upper wafer W1 hydrophilic (S104) and before bonding the upper wafer W1 and the lower wafer W2 (S110). . Since cleaning (S101) is performed immediately before bonding (S110), it is possible to suppress the introduction of deposits into the bonding device 41, and to eliminate problems during bonding.

Note that although the inspection of the upper wafer W1 (S102) shown in FIG. 13 is not performed in FIG. 20, it may be performed. Similar to cleaning (S101), inspection (S102) may also be performed after surface hydrophilization (S104) and before bonding (S110). Since the inspection (S102) is performed immediately before joining (S110), it is possible to suppress the introduction of deposits into the joining apparatus 41, and it is possible to eliminate problems during joining. The order of inspection (S102) and cleaning (S101) is not particularly limited, and either may come first.

Further, as shown in FIG. 20, cleaning of the lower wafer W2 (S106) is performed after making the surface of the lower wafer W2 hydrophilic (S109) and before bonding the upper wafer W1 and the lower wafer W2 (S110). Good too. Since cleaning (S106) is performed immediately before bonding (S110), it is possible to prevent deposits from being brought into the bonding device 41, and to eliminate problems during bonding.

Note that although the inspection of the lower wafer W2 (S107) shown in FIG. 13 is not performed in FIG. 20, it may be performed. Similarly to cleaning (S106), inspection (S107) may also be performed after surface hydrophilization (S109) and before bonding (S110). Since the inspection (S107) is performed immediately before joining (S110), it is possible to suppress the introduction of deposits into the joining apparatus 41, and it is possible to eliminate problems during joining. The order of inspection (S107) and cleaning (S106) is not particularly limited, and either may come first.

Although the embodiments of the joining system and joining method according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

The bonding system 1 of the above embodiment includes both the cleaning device 31 and the inspection device 32, but may include only one of them. If the bonding system 1 includes at least one of the cleaning device 31 and the inspection device 32, it is possible to suppress the deposits 7 from being carried into the bonding device 41, and therefore it is possible to suppress the generation of voids 8 during bonding.

When the bonding system 1 does not include the cleaning device 31 but includes the inspection device 32, the bonding system 1 collects in the cassette C4 those for which the inspection result of the inspection device 32 indicates that the deposit 7 is present. The collected upper wafer W1 or lower wafer W2 may be cleaned outside the bonding system 1 and then returned to the bonding system 1, or may be discarded.

In the above embodiment, the upper wafer W1 corresponds to the first substrate and the lower wafer W2 corresponds to the second substrate; Good too. Furthermore, although the first substrate and the second substrate are semiconductor substrates in the above embodiments, they may be glass substrates or the like.

1 Bonding system 31 Cleaning device 32 Inspection device 33 Surface modification device 35 Surface hydrophilization device 41 Bonding device 61 Transfer device 70 Control device W1 Upper wafer (first substrate)
W2 Lower wafer (second substrate)

Claims (20)

a surface modification device that modifies the bonding surface of the first substrate and the bonding surface of the second substrate;
a surface hydrophilization device that hydrophilizes the bonding surface of the modified first substrate and the bonding surface of the modified second substrate;
a bonding device for bonding the bonding surface of the hydrophilic first substrate and the hydrophilic bonding surface of the hydrophilic second substrate to face each other;
a cleaning device that cleans at least a non-bonded surface of the first substrate and the second substrate, which is held flat during bonding but is opposite to the bonded surface, before the bonding ;
The cleaning device includes a roughening section that roughens the non-bonding surface,
In the bonding system, the surface roughening section roughens the non-bonded surfaces of the first substrate and the second substrate that are deformed during bonding, except for the outer periphery thereof. The bonding system according to claim 1, wherein the cleaning device includes a polishing section that polishes the non-bond surface. The bonding system according to claim 2, wherein the polishing section includes a polishing sheet containing diamond abrasive grains. The joining system according to any one of claims 1 to 3 , wherein the cleaning device cleans at least an outer peripheral portion of the non-joining surface. The bonding system according to any one of claims 1 to 4 , wherein the cleaning device has a built-in cleaning section that is built into the surface hydrophilization device. The joining system according to any one of claims 1 to 5 , further comprising an inspection device for inspecting the presence or absence of deposits adhering to the non-joining surfaces before the joining. a transport device that transports the first substrate and the second substrate;
A control device for transporting at least one of the first substrate and the second substrate to be held flat during bonding to the cleaning device and the inspection device in this order using the transport device. 6. The joining system according to 6 . a transport device that transports the first substrate and the second substrate;
A control device for transporting at least one of the first substrate and the second substrate, which is held flat during bonding, to the inspection device and the cleaning device in this order using the transport device. 6. The joining system according to 6 . The control device may transport one of the first substrate and the second substrate, which has been inspected by the inspection device to have the deposit, to the cleaning device using the transfer device. 8. The joining system according to 7 or 8 . The control device is configured to transport one of the first substrate and the second substrate, which has been inspected by the inspection device to have the deposit, to the cleaning device using the transfer device; The joining system according to claim 9 , wherein the joining system is transported again to an inspection device. The control device prohibits the transport device from transporting one of the first substrate and the second substrate, which has been tested by the testing device to be free of the deposits, to the cleaning device. The joining system according to any one of claims 7 to 10. The bonding device includes a first substrate holding section that holds the first substrate, and a second substrate holding section that holds the second substrate,
The first substrate holding portion includes a first frame portion that supports an outer peripheral portion of the non-bonding surface of the first substrate, and a plurality of first pin portions distributed inside the first frame portion. ,
The second substrate holding portion includes a second frame portion that supports an outer peripheral portion of the non-bonding surface of the second substrate, and a plurality of second pin portions distributed inside the second frame portion. , the joining system according to any one of claims 1 to 11 . modifying the bonding surface of the first substrate and the bonding surface of the second substrate;
a step of making the bonding surface of the modified first substrate and the bonding surface of the modified second substrate hydrophilic;
a step of facing and bonding the bonding surface of the hydrophilic first substrate and the hydrophilic bonding surface of the second substrate;
Before the bonding step, a step of cleaning at least a non-bonding surface of the first substrate and the second substrate, which is held flat during bonding but is opposite to the bonding surface,
The cleaning step includes a step of roughening the non-bonding surface,
The cleaning step includes a step of roughening the non-bonded surfaces of the first substrate and the second substrate, which are deformed during bonding, except for the outer periphery thereof. 14. The bonding method according to claim 13 , wherein the cleaning step includes polishing the non-bonding surface. The bonding method according to any one of claims 13 to 14 , wherein the cleaning step includes a step of cleaning an outer peripheral portion of the non-bonding surface. 16. The joining method according to claim 13 , further comprising the step of inspecting the presence or absence of deposits adhering to the non-joining surfaces before the joining step. 17. The bonding method according to claim 16 , wherein the cleaning step is performed before the inspecting step. 17. The bonding method according to claim 16 , wherein the cleaning step is performed after the inspecting step. The bonding method according to any one of claims 16 to 18 , further comprising the step of cleaning the non-bonding surface on which the presence of the deposit was found in the inspecting step. 20. The bonding method according to claim 19 , further comprising the step of re-inspecting the non-bonding surface for the presence of the deposit after cleaning the non-bonding surface on which the presence of the deposit was found in the inspecting step.

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