CN105374725A - Joining device, joining system and joining method - Google Patents

Abstract

The invention provides a joining device, a joining system, and a joining method. The joining device (41) includes: an upper chuck (140) for aligning an upper wafer (W)_U) Vacuum sucking is performed to suck the upper wafer (W)_U) Adsorbed and held on the lower surface; and a lower chuck (141) provided below the upper chuck (140) and used for aligning a lower wafer (W)_L) Vacuum sucking is performed to hold the lower wafer (W)_L) Adsorbed and retained on the upper surface. The lower chuck (141) is provided for aligning a lower wafer (W)_L) A main body part (190) for vacuum suction and a vacuum suction device arranged on the main body part (190)And with the lower wafer (W)_L) A plurality of pins (191) contacting the back surface of the substrate. The tip position of a pin (191a) provided in the center of the body (190) is higher than the tip position of a pin (191b) provided in the outer periphery of the body (190).

Description

Joining device, joining system and joining method

technical field

The present invention relates to a bonding device for bonding substrates, a bonding system including the bonding device, and a bonding method using the bonding device.

Background technique

In recent years, high integration of semiconductor devices has been progressing. When arranging a plurality of highly integrated semiconductor devices in a horizontal plane and connecting these semiconductor devices with wires for commercialization, there are concerns about increased wire resistance and wire delay due to increase in wire length.

Therefore, it has been proposed to use a three-dimensional integration technology that three-dimensionally stacks semiconductor devices. In this three-dimensional integration technique, for example, two semiconductor wafers (hereinafter, referred to as “wafers”) are bonded using a bonding system described in Patent Document 1, for example. For example, the bonding system includes: a surface modification device, which is used to modify the surface of the wafer to be bonded; a surface hydrophilization device, which is used to make the surface of the wafer modified by the surface modification device surface hydrophilization; and a bonding device for bonding wafers whose surfaces have been hydrophilized by the surface hydrophilization device to each other. In this bonding system, the surface of a wafer is subjected to plasma treatment in a surface modification device to modify the surface, and then pure water is supplied to the surface of the wafer in a surface hydrophilization device to make the surface hydrophilic. After hydration, the wafers are bonded to each other in a bonder using van der Waals forces and hydrogen bonding (intermolecular forces).

The bonding device has: an upper suction cup, which is used to hold a wafer (hereinafter referred to as "upper wafer") on the lower surface; a lower suction cup, which is arranged below the upper suction cup, and is used to hold another wafer on the upper surface. a wafer (hereinafter referred to as “lower wafer”); and a pushing member provided on the upper chuck for pressing the center of the upper wafer. In this bonding apparatus, in a state where the upper wafer held by the upper chuck and the lower wafer held by the lower chuck are opposed to each other, the central portion of the upper wafer and the central portion of the lower wafer are pressed by a pushing member to The two are brought into contact, and then, in a state where the center portion of the upper wafer and the center portion of the lower wafer are in contact, the upper wafer and the lower wafer are sequentially moved from the center portion of the upper wafer toward the outer peripheral portion. join.

Patent Document 1: Japanese Patent No. 5538613

Contents of the invention

The problem to be solved by the invention

In addition, in the method described in Patent Document 1, since the center portion of the upper wafer is lowered toward the center portion of the lower wafer by the pushing member while the outer peripheral portion of the upper wafer is held by the upper chuck, this The upper wafer protrudes in a convexly warped manner downward. Then, when bonding the wafers, the upper wafer and the lower wafer may be bonded so as to be shifted in the horizontal direction. For example, in a bonded wafer (hereinafter referred to as "overlapped wafer"), even if the center portion of the upper wafer coincides with the center portion of the lower wafer, the outer peripheral portion of the upper wafer and the lower wafer Misalignment (scaling) also occurs in the horizontal direction.

However, in the bonding system described in Patent Document 1, no consideration is given to suppressing the displacement of the superimposed wafers in the horizontal direction. Therefore, there is room for improvement in the conventional bonding process between wafers.

The present invention has been made in view of this point, and an object of the present invention is to appropriately adjust the horizontal position of substrates to be bonded to appropriately perform the bonding process of the substrates.

solutions to problems

In order to achieve the above object, the present invention provides a bonding device, which is used for bonding substrates to each other. 1. The substrate is adsorbed and held on the lower surface; and a second holding part is provided below the first holding part, and is used for vacuum suctioning the second substrate to hold the second substrate on the upper surface. 2. The holding unit has a main body for vacuum suctioning the second substrate and a plurality of pins provided on the main body and in contact with the back surface of the second substrate, and the pins provided at the center of the main body The position of the tip of the pin is higher than the position of the tip of the pin provided on the outer peripheral portion of the main body.

According to the present invention, the center portion of the upper surface of the second holding portion protrudes from the outer peripheral portion of the upper surface of the second holding portion, and the second substrate is held along the upper surface of the second holding portion. That is, the central portion of the second substrate held by the second holding portion also protrudes from the outer peripheral portion of the second substrate. In this case, even if the center portion of the first substrate is pressed by, for example, a push member to protrude downward in a convexly warped manner, the second substrate is substantially vertically symmetrical to the first substrate. The shape sticks out in a way that is convexly warped upward. Therefore, displacement in the horizontal direction between the first substrate and the second substrate can be suppressed.

In addition, as described above, since the second substrate is held by the second holding portion so as to protrude upward, the central portion of the first substrate and the central portion of the second substrate can be reliably brought into contact by the push member. Then, the first substrate and the second substrate can be bonded sequentially from the center portion of the first substrate toward the outer peripheral portion in a state where the center portion of the first substrate and the center portion of the second substrate are brought into contact. In this case, as the substrates come into contact with each other sequentially from the center to the outer periphery, the air between the substrates can reliably flow out from the center to the outer periphery, and it is possible to suppress the occurrence of voids in the superimposed wafers after bonding. .

As described above, according to the present invention, it is possible to appropriately adjust the horizontal positions of the first substrate and the second substrate and suppress the generation of gaps between the superimposed substrates, so that the bonding process of the first substrate and the second substrate can be performed appropriately.

Alternatively, the main body may be divided into a concentric inner region and an outer region, and the tip positions of the plurality of pins provided in the inner region become lower toward the radially outer side, and the pins arranged in the outer region The tip positions of the plurality of pins of the region become lower toward the radially outer side, and the variation of the tip positions of the plurality of pins in the inner region with respect to the radial distance is smaller than that in the outer region. Variation of tip positions of multiple pins with respect to radial distance.

Alternatively, the joining device may further include a pushing member provided on the first holding portion for pressing the central portion of the first substrate.

Alternatively, the main body may be divided into a plurality of concentric pin regions, and among the plurality of pin regions, the intervals between the plurality of pins in the inner pin region are smaller than those in the outer pin region. spacing of the plurality of pins.

It is also possible that the second holding part further has a rib, which is concentrically and annularly provided on the main body part and protrudes from the main body part, and the second holding part can be set to The second substrate is vacuum-suctioned in each of the suction area inside the rib and the suction area outside the rib.

The second holding unit may further include a temperature adjustment mechanism for adjusting the temperature of the second substrate held by the second holding unit.

Another technical solution of the present invention provides a jointing system, which has the jointing device, and is characterized in that the jointing system includes: a processing station, which has the jointing device; and an input and output station, which can hold multiple A first substrate, a plurality of second substrates, and a plurality of laminated substrates formed by joining the first substrates and the second substrates are input and output to and from the processing station, and the processing station Including: a surface modification device, which is used to modify the surface to be bonded of the first substrate and the second substrate; a surface hydrophilization device, which is used to make the surface of the first substrate and the second substrate surface hydrophilization after modification by the modifying device; and a transport device for transporting the first substrate, the second substrate, and The substrates are stacked, and the first substrate and the second substrate whose surfaces have been hydrophilized by the surface hydrophilization device are bonded to each other in the bonding device.

Still another technical solution of the present invention provides a bonding method. In the bonding method, substrates are bonded to each other using a bonding device, and the bonding device includes: a first holding part for vacuuming the first substrate. sucking and holding the first substrate on the lower surface; a second holding part, which is arranged below the first holding part, is used to vacuum suck the second substrate and hold the second substrate on the upper surface and a pushing member, which is provided on the first holding part for pressing the center part of the first substrate, and the second holding part has a main body part for vacuum suctioning the second substrate and is provided on the The plurality of pins in the main body that are in contact with the back surface of the second substrate, the top ends of the pins provided in the central part of the main body are higher than the top ends of the pins provided in the outer peripheral part of the main body position, the bonding method includes the following steps: a first holding step, in which the first holding part is used to hold the first substrate; a second holding step, in the second holding step, using The second holding part holds the second substrate in such a manner that the center part of the second substrate protrudes upward; in the subsequent arrangement step, in the arrangement step, the first substrate held by the first holding part and the first substrate held by the first holding part are arranged. The second substrate held by the second holding part is arranged oppositely; in the subsequent pressing process, in the pressing process, the pushing member is lowered and the center portion of the first substrate and the center of the second substrate are aligned by the pushing member. portion is pressed so that the center portion of the first substrate and the center portion of the second substrate are brought into contact; In the state, the vacuum suction of the first substrate by the first holding part is stopped, and the first substrate and the second substrate are sequentially bonded from the center portion of the first substrate toward the outer peripheral portion.

Alternatively, the main body may be divided into a concentric inner region and an outer region, and the tip positions of the plurality of pins provided in the inner region become lower toward the radially outer side, and the pins arranged in the outer region The tip positions of the plurality of pins of the region become lower toward the radially outer side, and the variation of the tip positions of the plurality of pins in the inner region with respect to the radial distance is smaller than that in the outer region. In the second holding step, the tip positions of the plurality of pins are changed with respect to the radial distance, and the second substrate is held along the surface of the second holding portion.

Alternatively, the main body may be divided into a plurality of concentric pin regions, and among the plurality of pin regions, the intervals between the plurality of pins in the inner pin region are smaller than those in the outer pin region. In the pressing step, the center portion of the first substrate and the portion of the second substrate that is supported by the inner pin region are pressed by the pushing member to make the first substrate The central portion of the second substrate is in contact with the portion of the second substrate supported by the inner pin region.

It is also possible that the second holding part further has a rib, which is concentrically and annularly provided on the main body part and protrudes from the main body part, and the second holding part can be set to The second substrate is vacuum-suctioned in each of the suction region inside the rib and the suction region outside the rib, and in the second holding step, the second substrate is sucked and held in the suction region inside the rib. After the substrate is removed, the second substrate is sucked and held in the outer suction region.

In the bonding step, the first substrate and the second substrate may be bonded while adjusting the temperature of the second substrate by a temperature adjustment mechanism provided in the second holding unit.

The effect of the invention

According to the present invention, it is possible to properly adjust the horizontal position of substrates to be bonded and to suppress the generation of gaps between overlapping substrates, so that the bonding process of the substrates can be appropriately performed.

Description of drawings

FIG. 1 is a plan view showing a schematic configuration of a joining system according to this embodiment.

FIG. 2 is a side view showing an internal schematic configuration of the joining system according to the present embodiment.

FIG. 3 is a side view showing a schematic structure of an upper wafer and a lower wafer.

Fig. 4 is a transverse cross-sectional view showing a schematic configuration of the joining device.

Fig. 5 is a longitudinal sectional view showing a schematic configuration of a joining device.

Fig. 6 is a longitudinal sectional view showing a schematic structure of an upper pad and a lower pad.

Figure 7 is a plan view of the suction cup from below.

Fig. 8 is a plan view of the suction cup viewed from above.

FIG. 9 is a flowchart showing main steps of the wafer bonding process.

FIG. 10 is an explanatory view showing a state in which a lower wafer is sucked and held in a first suction region.

FIG. 11 is an explanatory view showing a state in which a lower wafer is sucked and held in a second suction region.

12 is an explanatory view showing a state where the center portion of the upper wafer and the center portion of the lower wafer are pressed and brought into contact.

FIG. 13 is an explanatory view showing a state in which an upper wafer is sequentially brought into contact with a lower wafer.

FIG. 14 is an explanatory view showing a state where the surface of the upper wafer and the surface of the lower wafer are brought into contact.

FIG. 15 is an explanatory view showing a state where an upper wafer and a lower wafer are bonded.

Fig. 16 is a longitudinal sectional view showing a schematic structure of a lower pad in another embodiment.

Fig. 17 is a plan view of a lower suction cup in another embodiment.

Fig. 18 is a plan view of a lower suction cup in another embodiment.

Fig. 19 is a longitudinal sectional view showing a schematic structure of a lower pad in another embodiment.

Fig. 20 is a longitudinal sectional view showing a schematic structure of a lower pad in another embodiment.

detailed description

Embodiments of the present invention will be described below. FIG. 1 is a plan view showing a schematic configuration of a bonding system 1 according to the present embodiment. FIG. 2 is a side view showing a schematic internal structure of the joining system 1 .

In the bonding system 1 , for example, two wafers W _U and W _L serving as substrates are bonded as shown in FIG. 3 . Hereinafter, the wafer disposed on the upper side is referred to as an "upper wafer W _U " as the first substrate, and the wafer disposed on the lower side is referred to as a "lower wafer W _L " as the second substrate. Also, the bonding surface of the upper wafer W _U is referred to as "surface W _U1 ", and the surface opposite to the surface W _U1 is referred to as "back surface W _U2 ". Likewise, the bonding surface of the lower wafer _WL to be bonded is referred to as "surface W _L1 ", and the surface opposite to this surface W _L1 is referred to as "back surface W _L2 ". Then, in the bonding system 1 , the upper wafer W _U and the lower wafer W _L are bonded to form a superimposed wafer W _T as a superimposed substrate.

As shown in FIG. 1 , the joining system 1 has, for example, a structure in which an input/output station 2 and a processing station 3 are integrally connected. The input/output station 2 provides input/output boxes C _U , _CL , and C _T , the boxes _CU , _{CL , and CT can accommodate multiple wafers W U , multiple} wafers _{W L} , and multiple overlapping wafers W _T , and the processing station 3 includes _a Various processing apparatuses for performing predetermined processing on the wafer _WT .

A cassette mounting table 10 is provided in the input/output station 2 . A plurality of, for example, four cartridge mounting plates 11 are provided on the cartridge mounting table 10 . The cartridge mounting plates 11 are arranged in a row in the X direction (vertical direction in FIG. 1 ) in the horizontal direction. When the cassettes _CU , _CL , _CT are loaded and exported to the outside of the joining system 1 , the cassettes _CU , _CL , _CT can be placed on these cassette mounting plates 11 . In this way, the input/output station 2 is configured to be able to hold a plurality of upper wafers W _U , a plurality of lower wafers W _L , and a plurality of stacked wafers W _T . In addition, the number of objects of the cassette mounting plate 11 is not limited to this embodiment, It can decide arbitrarily. Alternatively, one of the cassettes can be used to recover abnormal wafers. That is, it is a cassette capable of separating a wafer in which an abnormality has occurred in the bonding of the upper wafer W _U and the lower wafer W _L due to various reasons from other normal overlapping wafers W _T . In the present embodiment, one of the plurality of cassettes _CT is used to collect abnormal wafers, and the other cassettes _CT are used to store normal overlapping wafers W _{T .}

In the input/output station 2 , a wafer transfer unit 20 is provided adjacent to the cassette mounting table 10 . A wafer transfer device 22 movable on a transfer path 21 extending in the X direction is provided in the wafer transfer unit 20 . The wafer transfer device 22 can also move in the vertical direction and in the direction around the vertical axis (theta direction), and can move between the cassettes C _U , _CL , and _CT on each cassette mounting plate 11 and the processing station described later. The wafers W _U , W _L and the overlapped wafer W _T are transported between the transfer devices 50 and 51 of the third processing area G3 of 3.

Several, for example three, treatment zones G1 , G2 , G3 with various devices are provided in the treatment station 3 . For example, the first processing area G1 is set on the front side (the negative direction side of the X direction in FIG. 1 ) of the processing station 3, and the second processing area G1 is set on the back side (the positive direction side of the X direction of FIG. 1 ) of the processing station 3. Treatment area G2. In addition, a third processing area G3 is provided on the side of the processing station 3 close to the input/output station 2 (the side in the negative direction of the Y direction in FIG. 1 ).

For example, a surface modification device 30 for modifying the surface W _U1 of the wafer W _U and the surface W _L1 of the wafer W _L is arranged in the first processing area G1 . In the surface modifying device 30 , oxygen or nitrogen as a processing gas is excited to be plasma-formed and ionized, for example, under a reduced-pressure atmosphere. The surfaces W _U1 , W _L1 are irradiated with the oxygen ions or nitrogen ions to perform plasma treatment on the surfaces W _U1 , W _L1 , thereby modifying the surfaces W _U1 , W _L1 .

For example, in the second processing area G2, the hydrophilization device 40 and the bonding device 41 are arranged in the order of the surface hydrophilization device 40 and the bonding device 41 along the Y direction in the horizontal direction from the input and output station 2 side. The hydrophilization device 40 uses, for example, pure water to hydrophilize the surface W _U1 of the wafer W _U and the surface W _L1 of the wafer W _L and cleans the surfaces W _U1 and W _L1 . Wafers W _U , W _L are bonded.

In the surface hydrophilization apparatus 40, pure water is supplied onto the wafers _WU , _WL while rotating the wafers _WU , _WL held by, for example, a spin chuck. Then, the supplied pure water diffuses on the surfaces W _U1 , W _L1 of the wafers W _U , W _L to hydrophilize the surfaces W _U1 , W _L1 . In addition, the structure of the joining device 41 will be described later.

For example, as shown in FIG. 2 , transfer devices 50 , 51 for wafers W _U , W _L , and superimposed wafer W _T are provided sequentially in two layers from below in the third processing block G3 .

As shown in FIG. 1 , a wafer transfer area 60 is formed in an area surrounded by the first processing area G1 to the third processing area G3 . For example, a wafer transfer device 61 is arranged in the wafer transfer area 60 .

The wafer transfer device 61 has, for example, a transfer arm movable in a vertical direction, a horizontal direction (Y direction, X direction), and a direction around a vertical axis. The wafer conveying device 61 moves in the wafer conveying area 60, and can convey the wafers _WU , _WL , and overlapping wafers _WT to the surrounding first processing area G1, second processing area G2, and third processing area G3 within the specified device.

As shown in FIG. 1 , the above joining system 1 is provided with a control device 70 . The control device 70 is, for example, a computer, and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the wafers W _U , W _L and the overlapped wafer W _T in the bonding system 1 . In addition, the program storage unit also stores programs for controlling the operation of drive systems of the various processing devices, transport devices, and the like to realize wafer bonding processing to be described later in the bonding system 1 . In addition, the program is stored in a computer-readable storage medium H such as a computer-readable hard disk (HD), floppy disk (FD), compact disk (CD), optical disk (MO), memory card, etc., and the The program can also be installed from the storage medium H into the control device 70 .

Next, the configuration of the joining device 41 will be described. As shown in FIG. 4 , the joining device 41 has a processing container 100 whose interior can be hermetically sealed. An input/output port 101 for wafers W _U , W _L , and stacked wafer W _T is formed on the side surface of the processing container 100 near the wafer transfer region 60 , and a shutter 102 is provided on the input/output port 101 .

The inside of the processing container 100 is divided into a transfer area T1 and a processing area T2 by an inner wall 103 . The input/output port 101 is formed on the side of the processing container 100 at a portion in the transfer area T1. In addition, on the inner wall 103 are also formed output and output ports 104 for the wafers W _U , W _L , and the stacked wafer W _T .

A transfer device 110 for temporarily placing wafers W _U , W _L , and overlapping wafer W _T is provided on the positive direction side in the X direction of transfer area T1 . The transfer device 110 is formed in two layers, for example, and can simultaneously place any two wafers among the wafers W _U , W _L , and the overlapped wafer W _T .

A wafer transfer mechanism 111 is provided in the transfer region T1. As shown in FIGS. 4 and 5 , the wafer transfer mechanism 111 has, for example, a transfer arm movable in the vertical direction, in the horizontal direction (Y direction, X direction), and in directions around the vertical axis. Therefore, the wafer transport mechanism 111 can transport the wafers W _U , W _L , and the overlapped wafer W _T within the transport area T1 or between the transport area T1 and the processing area T2 .

A position adjustment mechanism 120 for adjusting the orientation of the wafers W _U , W _L in the horizontal direction is provided on the negative X direction side of the transfer area T1 . The position adjustment mechanism 120 includes: a base 121, which has a holding part (not shown), and the holding part is used to hold and _rotate the _{wafers WU , WL} ; the detection part 122, which uses The positions of the notches of the wafers W _U and W _L are detected. In addition, in the position adjustment mechanism 120, the position of the notch portion of the wafer W _U , W _L is detected by the detection unit 122 while rotating the wafer W _U , W _L held by the susceptor 121, thereby adjusting the position of the wafer W U , W L. The orientation of the wafers W _U , W _L in the horizontal direction is adjusted according to the positions of the notches. In addition, the method of holding wafers W _U and W _L on susceptor 121 is not particularly limited, and various methods such as a pin chuck method and a spin chuck method can be used, for example.

In addition, an inverting mechanism 130 for inverting the front and back of the upper wafer _WU is provided in the transfer area T1. The turning mechanism 130 has a holding arm 131 for holding the upper wafer W _U. The holding arm 131 extends in the horizontal direction (Y direction). In addition, holding members 132 for holding the upper wafer W _U are provided at, for example, four places on the holding arm 131 .

The holding arm 131 is supported by a driving unit 133 having, for example, a motor or the like. The holding arm 131 is rotatable around a horizontal axis by the drive unit 133 . In addition, the holding arm 131 is rotatable around the drive unit 133 and movable in the horizontal direction (Y direction). Another drive unit (not shown) having, for example, a motor or the like is provided below the drive unit 133 . The drive unit 133 can move in the vertical direction along the support column 134 extending in the vertical direction by the other drive unit. In this way, the upper wafer W _U held by the holding member 132 can be rotated around the horizontal axis by the driving unit 133 and moved in the vertical direction and the horizontal direction. In addition, the upper wafer W _U held by the holding member 132 can rotate around the driving unit 133 and move between the position adjustment mechanism 120 and the upper chuck 140 described later.

In the processing area T2, there are provided an upper chuck 140 as a first holding portion and a lower chuck 141 as a second holding portion. The upper chuck 140 sucks and holds the upper wafer W _U by using the lower surface, and the lower chuck 141 uses the upper surface. To load and hold the lower wafer W _L by suction. The lower suction pad 141 is provided below the upper suction pad 140 and configured to be able to face the upper suction pad 140 . That is, the upper wafer W _U held by the upper chuck 140 and the lower wafer W _L held by the lower chuck 141 can be arranged facing each other.

The upper pad 140 is supported by an upper pad support portion 150 provided above the upper pad 140 . The upper chuck supporting part 150 is disposed on the top surface of the processing container 100 . That is, the upper chuck 140 is fixedly provided on the processing container 100 via the upper chuck support part 150 .

The upper chuck support unit 150 is provided with an upper imaging unit 151 for imaging the surface W _L1 of the lower wafer W _L held by the lower chuck 141 . That is, the upper imaging unit 151 is provided adjacent to the upper chuck 140 . As the upper imaging unit 151, for example, a CCD camera can be used.

The lower pad 141 is supported by the first lower pad moving part 160 provided below the lower pad 141 . The first lower pad moving unit 160 is configured to move the lower pad 141 in the horizontal direction (Y direction) as will be described later. In addition, the first lower pad moving unit 160 is configured to be able to move the lower pad 141 in the vertical direction and to be able to rotate around the vertical axis.

The first lower chuck moving unit 160 is provided with a lower imaging unit 161 for imaging the surface W _U1 of the upper wafer W _U held by the upper chuck 140 . That is, the lower imaging unit 161 is provided adjacent to the lower pad 141 . As the lower imaging unit 161, for example, a CCD camera can be used.

The first lower pad moving part 160 is attached to a pair of guide rails 162 and 162 extending in the horizontal direction (Y direction), and the pair of guide rails 162 and 162 are provided on the lower surface side of the first lower pad moving part 160 . Therefore, the first lower pad moving part 160 is configured to be movable along the guide rail 162 .

A pair of guide rails 162 , 162 is disposed on the second lower pad moving portion 163 . The second lower pad moving part 163 is attached to a pair of guide rails 164 , 164 extending in the horizontal direction (X direction), and the pair of guide rails 164 , 164 are provided on the lower surface side of the second lower pad moving part 163 . Then, the second lower pad moving part 163 is configured to be movable along the guide rail 164 , that is, configured to move the lower pad 141 in the horizontal direction (X direction). In addition, a pair of guide rails 164 and 164 are disposed on a mounting table 165 provided on the bottom surface of the processing container 100 .

Next, the detailed structure of the upper suction pad 140 and the lower suction pad 141 of the joining device 41 will be described.

As shown in FIGS. 6 and 7 , the upper suction cup 140 adopts a pin suction cup method. The upper chuck 140 has a main body portion 170 having a diameter at least larger than that of the upper wafer W _U in a plan view. A plurality of pins 171 that are in contact with the rear surface W _U2 of the upper wafer W _U are provided on the lower surface of the main body 170 . In addition, an annular rib 172 is provided on the lower surface of the main body portion 170 outside the plurality of pins 171 . The rib 172 supports at least the outer peripheral portion of the rear surface W _U2 of the upper wafer W _U so as to support at least the outer peripheral portion of the rear surface W _U2 of the upper wafer W U.

In addition, another rib 173 is provided on the lower surface of the main body portion 170 at the inner side of the rib 172 . The rib 173 is provided in an annular shape concentrically with the rib 172 . And, the area 174 inside the rib 172 (hereinafter, sometimes referred to as the suction area 174 ) is divided into a first suction area 174 a inside the rib 173 and a second suction area 174 b outside the rib 173 .

A first suction port 175a for vacuum suctioning the upper wafer W _U is formed in the first suction area 174a on the lower surface of the main body portion 170 . The first suction ports 175a are formed, for example, at two places in the first suction region 174a. The first suction port 175a is connected to a first suction pipe 176a provided inside the main body 170 . Furthermore, the first suction pipe 176a is connected to the first vacuum pump 177a via a joint.

In addition, a second suction port 175b for vacuum suctioning the upper wafer W _U is formed in the second suction region 174b on the lower surface of the main body portion 170 . The second suction port 175b is formed, for example, at two places in the second suction area 174b. The second suction port 175b is connected to a second suction pipe 176b provided inside the main body 170 . And the 2nd suction pipe 176b is connected to the 2nd vacuum pump 177b via a joint.

As described above, the upper chuck 140 is configured to be able to vacuum-suction the upper wafer WU in each of the first suction area _174a and the second suction area 174b. In addition, the arrangement|positioning of suction opening 175a, 175b is not limited to this embodiment, It can set arbitrarily.

Then, the suction regions 174a and 174b formed surrounded by the upper wafer W _U , the main body 170 and the rib 172 are vacuumed from the suction ports 175a and 175b respectively, thereby reducing the pressure in the suction regions 174a and 174b. At this time, since the atmosphere outside the suction regions 174a and 174b is at atmospheric pressure, the upper wafer WU is pressed toward the suction regions 174a and _174b by the atmospheric pressure according to the amount of decompression, thereby sucking the upper wafer _WU . Hold on the upper suction cup 140.

In this case, since the ribs 172 support the outer peripheral portion of the back surface W _U2 of the upper wafer W _U , the upper wafer W _U can be suitably vacuumed up to the outer peripheral portion of the upper wafer W _U. . Therefore, the entire surface of the upper wafer W _U can be adsorbed and held by the upper chuck 140 to reduce the flatness of the upper wafer W _U , thereby making the upper wafer W _U flat.

In addition, since the heights of the plurality of pins 171 are uniform, the flatness of the lower surface of the upper suction cup 140 can be further reduced. By making the lower surface of upper chuck 140 flat in this way (reducing the flatness of the lower surface), deformation in the vertical direction of upper wafer W _U held by upper chuck 140 can be suppressed.

In addition, since the back surface _WU2 of the upper wafer _WU is supported by a plurality of pins 171, the upper wafer _WU is easily peeled off from the upper chuck 140 when the vacuum suction of the upper wafer _WU by the upper chuck 140 is released. Down.

A through hole 178 penetrating through the main body 170 in the thickness direction is formed at the center of the main body 170 of the upper chuck 140 . The central portion of the main body portion 170 corresponds to the central portion of the upper wafer W _U sucked and held by the upper chuck 140 . Also, the tip end portion of the driver portion 181 of the pusher member 180 described later is inserted into the through hole 178 .

A pushing member 180 for pressing the center of the upper wafer W _U is provided on the upper surface of the upper chuck 140 . The pushing member 180 has a driver portion 181 and a cylinder portion 182 .

The driver part 181 generates a constant pressure in a constant direction using air supplied from an electro-pneumatic pressure regulating valve (not shown), and can generate the pressure constantly regardless of the position of the point of action of the pressure. In addition, the pressing load applied to the center of the upper wafer W _U can be controlled by bringing the driver unit 181 into contact with the center of the upper wafer W _U using air from the electro-pneumatic regulator. In addition, the tip end of the actuator unit 181 is inserted into the through hole 178 by air from the electro-pneumatic pressure regulating valve so that it can be raised and lowered in the vertical direction.

The driver unit 181 is supported by the cylinder unit 182 . The cylinder unit 182 can move the driver unit 181 in the vertical direction by, for example, a drive unit incorporating a motor.

As described above, the pushing member 180 uses the driver part 181 to control the pressing load and uses the cylinder part 182 to control the movement of the driver part 181 . Therefore, when wafers W _U and W _L are bonded to be described later, the pushing member 180 can bring the center of the upper wafer W _U and the center of the lower wafer W _L into contact and press them.

As shown in FIGS. 6 and 8 , like the upper pad 140 , the lower pad 141 adopts a pin chuck method. The lower chuck 141 has a main body portion 190 having a diameter at least larger than that of the lower wafer _WL in plan view.

On the upper surface of the main body portion 190, a plurality of pins 191 that are in contact with the rear surface _WL2 of the lower wafer _WL are provided. Among the plurality of pins 191 , the tip position of a pin 191 a provided in the central portion of the main body portion 190 is higher than the tip position of a pin 191 b provided in the outer peripheral portion of the main body portion 190 . Also, the plurality of pins 191 are provided such that their heights gradually decrease from the center portion toward the outer peripheral portion.

In addition, an annular rib 192 is provided on the upper surface of the main body 190 outside the plurality of pins 191 . The ribs 192 support the outer peripheral portion of the rear surface W _L2 of the lower wafer _WL so as to support at least the outer edge portion of the rear surface W _L2 .

Further, another rib 193 is provided on the upper surface of the main body portion 190 at a portion located inside the rib 192 . The rib 193 is provided in an annular shape concentrically with the rib 192 . And, the area 194 inside the rib 192 (hereinafter, sometimes referred to as the suction area 194 ) is divided into a first suction area 194 a inside the rib 193 and a second suction area 194 b outside the rib 193 .

In the first suction region 194a on the upper surface of the main body portion 190, a first suction port _195a for vacuum suctioning the lower wafer WL is formed. The first suction ports 195a are formed, for example, at two places in the first suction region 194a. The first suction port 195a is connected to a first suction pipe 196a provided inside the main body 190 . Furthermore, the first suction pipe 196a is connected to the first vacuum pump 197a via a joint.

In addition, a second suction port _195b for vacuum suctioning the lower wafer WL is formed in the second suction region 194b on the upper surface of the main body portion 190 . The second suction port 195b is formed, for example, at two places in the second suction area 194b. The second suction port 195b is connected to a second suction pipe 196b provided inside the main body 190 . Furthermore, the second suction pipe 196b is connected to the second vacuum pump 197b via a joint.

As described above, the lower chuck 141 is configured to be able to vacuum-suction the lower wafer WL in each of the first suction area 194a and the second suction area _194b . In addition, the arrangement|positioning of suction opening 195a, 195b is not limited to this embodiment, It can set arbitrarily.

Then, the suction regions 194a and 194b formed surrounded by the lower wafer W _L , the main body 190 and the ribs 192 are vacuumed from the suction ports 195a and 195b, respectively, thereby decompressing the suction regions 194a and 194b. At this time, since the atmosphere outside the suction regions 194a and 194b is at atmospheric pressure, the lower wafer WL is pressed toward the suction regions 194a and _194b by the atmospheric pressure according to the amount of decompression, thereby sucking the lower wafer _WL . Hold on the lower suction cup 141.

In this case, since the ribs 192 support the outer periphery of the back surface _WL2 of the lower wafer _WL , the lower wafer _WL can be suitably _vacuumed up to the outer periphery of the lower wafer WL. . And, the lower wafer W _L is held along the upper surface of the lower chuck 141 . That is, since the heights of the plurality of pins 191 gradually decrease from the center to the outer periphery of the lower chuck 141, the lower wafer _WL is also held such that the center protrudes from the outer periphery.

In addition, since the back surface _WL2 of the lower wafer _WL is supported by the plurality of pins 191, the lower wafer _WL is easily peeled off from the lower chuck 141 when the vacuum suction of the lower wafer _WL by the lower chuck 141 is released. Down.

Through-holes 198 penetrating through the main body 190 in the thickness direction are formed at, for example, three locations near the center of the main body 190 of the lower chuck 141 . Further, the lift pins provided below the first lower pad moving portion 160 are inserted into the through holes 198 .

A guide member 199 is provided on the outer peripheral portion of the main body portion 190 for preventing the wafers W _U , W _L , and the overlapped wafer W _T from flying out or sliding down from the lower chuck 141 . The guide members 199 are provided at equal intervals at a plurality of locations, for example, four locations, on the outer peripheral portion of the main body portion 190 .

In addition, the operation of each part of the joining device 41 is controlled by the control unit 70 .

Next, a bonding processing method of wafers _WU , _WL performed using bonding system 1 configured as described above will be described. FIG. 9 is a flowchart showing an example of main steps of the wafer bonding process.

First, a cassette CU containing a plurality of upper wafers _{W U} , a cassette _CL containing a plurality of lower wafers _WL , and an empty cassette _CT are placed on a predetermined cassette loading plate 11 of the input/output station 2 . Afterwards, the upper wafer W _U in the cassette _{CU is taken out by the wafer transfer device 22 , and the upper wafer W U is} transferred to the transfer device 50 of the third processing area G3 of the processing station 3 .

Next, the upper wafer W _U is transported by the wafer transport device 61 to the surface modification device 30 in the first processing area G1. In the surface modification device 30 , oxygen or nitrogen as a processing gas is excited to be plasma-formed and ionized under a predetermined reduced-pressure atmosphere. The oxygen ions or nitrogen ions are irradiated upward to the surface W _U1 of the wafer W _U to perform plasma treatment on the surface W _U1 . Then, the surface W _U1 of the upper wafer W _U is modified (step S1 of FIG. 9 ).

Next, the upper wafer _WU is transported by the wafer transport device 61 to the surface hydrophilization device 40 in the second processing area G2. In the surface hydrophilization apparatus 40 , pure water is supplied onto the upper wafer W _U while rotating the upper wafer W _U held by the spin chuck. Then, the supplied pure water diffuses on the surface W _U1 of the upper wafer W _U , and hydroxyl groups (silanol groups) adhere to the surface W _U1 of the upper wafer W _U modified by the surface modification device 30. Thus, the surface W _U1 is hydrophilized. In addition, the surface W _U1 of the upper wafer W _U is washed with this pure water (step S2 in FIG. 9 ).

Next, the upper wafer W _U is transported by the wafer transport device 61 to the bonding device 41 in the second processing block G2. The upper wafer W _U input to the bonding device 41 is transported to the position adjustment mechanism 120 by the wafer transport mechanism 111 via the transport device 110 . Then, the orientation of the upper wafer W _U in the horizontal direction is adjusted by the position adjustment mechanism 120 (step S3 in FIG. 9 ).

Thereafter, the upper wafer W _U is delivered from the position adjustment mechanism 120 to the holding arm 131 of the inverting mechanism 130 . Next, in the transfer region T1, the upper wafer _WU is turned over by turning over the holding arm 131 (step S4 in FIG. 9 ). That is, the surface W _U1 of the upper wafer W _U is directed downward.

Thereafter, the holding arm 131 of the inverting mechanism 130 is rotated around the drive unit 133 to move below the upper suction pad 140 . Then, the upper wafer W _U is transferred from the turning mechanism 130 to the upper chuck 140 . The back surface W _U2 of the upper wafer W _U is sucked and held by the upper chuck 140 . (Step S5 of FIG. 9). Specifically, the vacuum pumps 177a, 177b are operated to vacuum-suction the upper wafer WU through the suction ports 175a, _175b in the suction regions 174a, _174b , thereby suctioning and holding the upper wafer WU on the upper chuck 140.

While the upper wafer W _U is being processed in steps S1 to S5, the lower wafer WL is then processed next to the upper wafer _{W U.} First, the lower wafer W _L in the cassette _CL is taken out by the wafer transfer device 22 , and the lower wafer W _L is transferred to the transfer device 50 of the processing station 3 .

Next, the lower wafer _WL is transferred to the surface modification device 30 by the wafer transfer device 61, and the surface _WL1 of the lower wafer _WL is modified (step S6 in FIG. 9 ). In addition, the modification of the surface _WL1 of the lower wafer _WL in the step S6 is the same as that of the step S1.

Thereafter, the lower wafer _WL is transported to the surface hydrophilization device 40 by the wafer transport device 61, and the surface _WL1 of the lower wafer _WL is hydrophilized and _cleaned (step S7 in FIG. 9 ). In addition, the hydrophilization and cleaning of the surface _WL1 of the lower wafer _WL in the step S7 are the same as in the step S2.

Thereafter, the lower wafer W _L is transferred to the bonding device 41 by the wafer transfer device 61 . The lower wafer W _L input to the bonding device 41 is transported to the position adjustment mechanism 120 by the wafer transport mechanism 111 via the transport device 110 . Then, the orientation of the lower wafer _WL in the horizontal direction is adjusted by the position adjustment mechanism 120 (step S8 in FIG. 9 ).

Thereafter, the lower wafer _WL is transferred to the lower chuck 141 by the wafer transfer mechanism 111, and the back surface _WL2 of the lower wafer WL is sucked and held by the lower chuck ₁₄₁ (step S9 in FIG. 9 ). In step S9, first, the first vacuum pump _197a is operated to vacuum-suction the lower wafer WL from the first suction port 195a in the first suction region 194a as shown in FIG. 10 . Then, the position in the horizontal direction of the lower wafer _WL is fixed. Thereafter, in the state where the first vacuum pump 197a is activated, the second vacuum pump _197b is further activated to perform vacuum suction on the lower wafer WL from the suction ports 195a, 195b in the suction regions 194a, 194b as shown in FIG. . Then, the entire surface of the lower wafer _WL is sucked and held by the lower chuck 141 . At this time, as described above, the lower wafer _WL is held along the upper surface of the lower chuck 141 such that the central portion protrudes from the outer peripheral portion.

Next, the positions in the horizontal direction of the upper wafer W _U held by the upper chuck 140 and the lower wafer W _L held by the lower chuck 141 are adjusted. Specifically, the lower chuck 141 is moved in the horizontal direction (X direction and Y direction) by the first lower chuck moving unit 160 and the second lower chuck moving unit 163, and the surface _W of the lower wafer WL is imaged by the upper imaging unit 151. The predetermined reference points on _L1 are photographed sequentially. At the same time, predetermined reference points on the surface W _U1 of the upper wafer W _U are sequentially photographed using the lower imaging unit 161 . The captured image is output to the control unit 70 . In the control unit 70, based on the image captured by the upper imaging unit 151 and the image captured by the lower imaging unit 161, the lower chuck 141 is moved to The reference points of the upper wafer W _U and the reference points of the lower wafer W _L are aligned with each other. In this way, the horizontal positions of the upper wafer W _U and the lower wafer W _L can be adjusted (step S10 in FIG. 9 ).

Afterwards, the lower chuck 141 is moved vertically upward by the first lower chuck moving unit 160 to adjust the vertical positions of the upper chuck 140 and the lower chuck 141, and the upper wafer W _U held by the upper chuck 140 is adjusted. The position in the vertical direction of the lower wafer W _L held by the lower chuck 141 is adjusted (step S11 in FIG. 9 ).

Next, bonding processing is performed on the upper wafer W _U held by the upper chuck 140 and the lower wafer W _L held by the lower chuck 141 .

First, as shown in FIG. 12 , the actuator part 181 is lowered by the cylinder part 182 of the pushing member 180 . Then, as the driver unit 181 descends, the center portion of the upper wafer W _U is pressed and descends. At this time, a predetermined pressing load is applied to the actuator unit 181 by the air supplied from the electro-pneumatic pressure regulating valve. Then, the central portion of the upper wafer W _{U and the central portion of the lower wafer W L are brought into contact by the pushing member 180 to press the central portion of the upper wafer W U and the} central portion of the lower wafer W _L ( FIG. 9 Step S12). At this time, the first vacuum pump 177a is stopped to stop the vacuum suction of the upper wafer W _U from the first suction port 175a in the first suction area 174a, and the second vacuum pump 177b is operated to perform vacuum suction from the second vacuum pump 177b. The port 175b evacuates the second suction area 174b. Furthermore, when the center portion of the upper wafer W _U is pressed by the pushing member 180 , the outer peripheral portion of the upper wafer W _U can also be held by the upper chuck 140 .

Then, bonding starts between the pressed center portion of the upper wafer W _U and the center portion of the lower wafer W _L (thick line portion in FIG. 12 ). That is, since the surface W _U1 of the upper wafer W _U and the surface W _L1 of the lower wafer W _L are respectively modified in steps S1 and S6, _first , _a van der Waals force ( Intermolecular force) to join the surfaces W _U1 , W _L1 to each other. Afterwards, since the surface W _U1 of the upper wafer W _U and the surface W _L1 of the lower wafer W _L are hydrophilized in steps S2 and S7 respectively, the hydrophilic groups between the surfaces W _U1 and W _L1 are generated Hydrogen bonding (intermolecular force) firmly bonds the surfaces W _U1 and W _L1 to each other.

In this step S12, the center portion of the upper wafer W _U is pressed and lowered, and the outer peripheral portion of the upper wafer W _U is held by the upper chuck 140, so that the upper wafer W _U warps convexly downward. way out. On the other hand, along the upper surface of lower chuck 141 , the center portion of lower wafer _{WL protrudes} more than the outer peripheral portion of lower wafer WL, and lower chuck 141 protrudes so as to be convexly warped upward. Therefore, the upper wafer _WU and the lower wafer _WL can be made to have approximately vertically symmetrical shapes, and the protrusion amounts of the upper wafer _WU and the lower wafer _WL can be made approximately the same. Therefore, displacement (scaling) in the horizontal direction at the time of bonding of the upper wafer W _U and the lower wafer W _L can be suppressed.

Afterwards, as shown in FIG. 13 , in a state where the center portion of the upper wafer W _U and the center portion of the lower wafer W _L are pressed by the pusher member 180, the second vacuum pump 177b is stopped to stop the suction from the second suction area. The second suction pipe 176b in 174b performs vacuum suction on the upper wafer W _U. Then, the upper wafer W _U drops onto the lower wafer W _L . At this time, since the back surface W _U2 of the upper wafer W _U is supported by a plurality of pins 171, the upper wafer W _U is easily lifted from the upper chuck 140 when the vacuum suction of the upper wafer W _U by the upper chuck 140 is released. peel off. Then, the upper wafer W _U sequentially falls onto the lower wafer W _L and comes into contact with the lower wafer W _L , and the bonding based on the van der Waals force and hydrogen bonding between the surfaces W _U1 and W _L1 spreads sequentially. In this way, as shown in FIG. 14 , the _{upper wafer W U and the} lower wafer _{W L} are bonded ₍ Step S13 of FIG. 9 ).

Here, in the step S12, since the lower wafer W _L is held by the lower chuck 141 so as to protrude upward, the center of the upper wafer W _U and the center of the lower wafer W _L can be aligned by the pushing member 180 . Reliable abutment. Therefore, in step S13, when the upper wafer W _U and the lower wafer W _L are sequentially brought into contact from the center toward the outer periphery, the air between these wafers W _U and W _L can be made to flow from the center toward the outer periphery. The parts flow out reliably, and it is possible to suppress the occurrence of voids in the superposed wafers _WT after bonding.

Thereafter, as shown in FIG. 15 , the driver portion 181 of the pushing member 180 is raised to the upper suction pad 140 . In addition, the operation of the vacuum pumps _197a and _197b is stopped to stop the vacuum suction of the lower wafer WL in the suction region 194, thereby stopping the suction and holding of the lower wafer WL by the lower chuck 141. At this time, since the back surface _WL2 of the lower wafer _WL is supported by the plurality of pins 191, the lower wafer _WL is easily released from the lower chuck 141 when the vacuum suction of the lower wafer _WL by the lower chuck 141 is released. peel off.

The superposed wafer W _T formed by bonding the upper wafer W _U and the lower wafer W _L is transported to the transport device 51 by the wafer transport device 61, and then the superposed wafer W is transported by the wafer transport device 22 of the input and output station 2. _T is transported to the cassette C _T of the predetermined cassette loading plate 11 . In this way, a series of bonding processes of wafers W _U and W _L are completed.

According to the above embodiment, the lower wafer W _L is held by the lower chuck 141 so as to protrude upward. Therefore, in step S12, even if the center portion of upper wafer W _U is pressed by pushing member 180 and the center portion of upper wafer W _U protrudes downward in a convexly warped manner, the lower wafer W _L It also protrudes so as to be convexly _warped upward in a substantially vertically symmetrical shape to the upper wafer WU. Therefore, by setting the protrusion amounts of the upper wafer _WU and the lower wafer _WL to be the same, it is possible to suppress the displacement (scaling) of the upper wafer _WU and the lower wafer _WL in the horizontal direction.

Furthermore, since the lower chuck 141 is divided into the first suction region 194a and the second suction region _194b by the rib 192, the lower wafer WL can be held by the lower chuck 141 in two stages in step S9. That is, first, since the lower wafer WL is vacuum-suctioned in the first suction region _194a to fix the position in the horizontal direction of the lower wafer WL, thereafter, in the suction regions 194a and _194b , When the lower wafer _WL is vacuum-suctioned, the position of the lower wafer _WL in the horizontal direction does not shift. Therefore, the lower wafer _WL can be sucked and held at an appropriate position on the lower chuck 141, and the scaling can be further suppressed.

In addition, the upper wafer W _U and the lower wafer W _L may be any one of a device wafer and a supporting wafer. A device wafer is a semiconductor wafer that becomes a product, for example, devices having a plurality of electronic circuits and the like are formed on the surface of the device wafer. In addition, the support wafer is a wafer for supporting a device wafer, and devices are not formed on the surface of the support wafer. Furthermore, the present invention can also be applied to any one of bonding processing between a device wafer and a support wafer and bonding processing between device wafers. However, when device wafers are to be bonded to each other, in order for the bonded superimposed wafer W _T to function properly as a product, it is necessary to make the electronic circuit of the upper wafer W _U and the electronic circuit of the lower wafer W _L The loops correspond appropriately. Therefore, suppression of scaling as described above is particularly useful for the bonding process between device wafers.

In addition, since the lower wafer W _L is held by the lower chuck 141 so as to protrude upward, in step S12, the center portion of the upper wafer W _U and the center of the lower wafer W _L can be moved by the pushing member 180 . The center part is reliably abutted. Therefore, in step S13, when the upper wafer W _U and the lower wafer W _L are brought into contact, the air between the upper wafer W _U and the lower wafer W _L reliably flows out from the center to the outer periphery. Accordingly, it is possible to suppress generation of voids in the superposed wafer _WT after bonding.

As described above, according to the present embodiment, it is possible to appropriately adjust the horizontal positions of the upper wafer W _U and the lower wafer W _L and to suppress the generation of gaps in the overlapped wafer W _T , so that the upper wafer W can be properly processed. Bonding process of _U and lower wafer W _L.

In addition, the bonding system 1 of this embodiment includes, in addition to the bonding device 41, a surface modifying device 30 for modifying the surfaces W _U1 , W _L1 of the wafers W _U , W _L . Since the surface hydrophilization apparatus 40 hydrophilizes the surfaces W _U1 and W _L1 and cleans the surfaces W _U1 and W _L1 , bonding of the wafers W _U and W _L can be efficiently performed in one system. Therefore, the productivity of the wafer bonding process can be further improved.

Next, another embodiment of the lower pad 141 in the joining device 41 of the above embodiment will be described.

As shown in FIGS. 16 and 17 , the main body portion 190 of the lower pad 141 may be divided into a first pin area 200 and a second pin area 201 according to the arrangement density of the pins 191 . The first pin region 200 is provided in a circular shape at the center of the main body 190 . The second pin region 201 is annularly provided outside the first pin region 200 so as to be concentric with the first pin region 200 . Furthermore, the intervals between the pins 191 provided in the first pin region 200 are smaller than the intervals between the pins 191 provided in the second pin region 201 .

As described above, in step S12, the pusher member 180 presses the center portion of the upper wafer _WU and the center portion of the lower wafer _WL (first pin region 200). Then, the center portion of the lower wafer W _L may be deformed vertically downward due to the pressing load. Therefore, by reducing the distance between the pins 191 in the first pin region 200 as shown in FIG. 16 , it is possible to suppress deformation in the vertical direction of the central portion of the lower wafer _WL .

In addition, as shown in FIG. 18 , the main body portion 190 of the lower chuck 141 may be divided into a first pin area 210 , a second pin area 211 , and a third pin area 212 according to the arrangement density of the pins 191 . 3 pin areas. The first pin area 210 , the second pin area 211 , and the third pin area 212 are concentrically arranged in order from the center toward the outer periphery. Furthermore, the intervals between the pins 191 provided in the first pin region 210 are smaller than the intervals between the pins 191 provided in the second pin region 211 . Furthermore, the intervals between the pins 191 provided in the second pin region 211 are smaller than the intervals between the pins 191 provided in the third pin region 212 . By increasing the distance between the pins 191 stepwise from the center toward the outer periphery in this way, the contact area of the lower wafer W _L supported by the lower chuck 141 can be smoothly varied and the center portion of the lower wafer W _L can be suppressed. The deformation in the vertical direction enables the lower wafer W _L to be more properly held by the lower chuck 141 . In addition, the number of pin regions is not limited to this embodiment, but can be set arbitrarily. The greater the number of divided pin regions, the more remarkably the effect can be obtained.

In addition, as shown in FIG. 19 , the lower chuck 141 may have a temperature adjustment mechanism 220 for adjusting the temperature of the lower wafer _WL held by the lower chuck 141 . The temperature adjustment mechanism 220 is built in, for example, the main body part 190 . In addition, as the temperature adjustment mechanism 220, for example, a heater is used. In this case, by heating the lower wafer W _L to a predetermined temperature, for example, normal temperature (23°C) to 100°C, by the temperature adjustment mechanism 220, the wafer WU, wafer _WU , Air between W _L. Therefore, it is possible to more reliably suppress the occurrence of voids on the superimposed wafer _WT .

In addition, the plurality of pins 191 of the lower suction cup 141 in the above embodiment are provided such that their heights gradually decrease from the center toward the outer periphery, but the change in the height of the plurality of pins 191 is not limited to this. In the following description, when the tip positions of the plurality of pins 191 are lowered toward the radially outer side of the lower chuck 141, the change in the radial distance of the tip positions of the plurality of pins 191 with respect to the lower chuck 141 is referred to as "height". Variety".

For example, as shown in FIG. 20 , the main body portion 190 of the lower pad 141 may be divided into an inner area 230 and an outer area 231 according to the change in height of the pin 191 . The inner area 230 is circularly disposed at the center of the main body 190 . The outer region 231 is annularly provided outside the inner region 230 so as to be concentric with the inner region 230 . In addition, the change in height of the pins 191 provided in the inner region 230 is smaller than the change in height of the pins 191 provided in the outer region 231 .

In this case, the force acting on the portion of the lower wafer _WL held by the inner region 230 and the force acting on the portion of the lower wafer _WL held by the outer region 231 can be made the same by balloon inflation, for example. That is, the in-plane force acting on the lower wafer _WL can be made uniform. Therefore, the lower wafer W _L can be more properly held by the lower chuck 141 .

In the lower chuck 141 of the above embodiment, the annular rib 192 for _supporting the outer peripheral portion of the lower wafer _WL is provided for vacuum suction up to the outer peripheral portion of the lower wafer WL. However, the structure for _vacuuming the outer peripheral portion of the lower wafer WL is not limited to this. For example, vacuum suction may be performed up to the outer peripheral portion of the lower wafer _WL by using so-called static pressure sealing. Specifically, instead of the rib 192, a rib (see figure) that does not come into contact with the lower wafer _WL may be provided on the outer peripheral portion of the main body portion 190, or the rib 192 may be omitted and the rib 192 may be extended to the outer periphery of the lower wafer _WL . The pin 191 is provided in the range up to the end. Then, the suction pressure by the second vacuum pump _197b is adjusted so that vacuum suction is performed up to the outer peripheral portion of the lower wafer WL.

In addition, the modified examples of the lower pad 141 shown in FIGS. 16 to 19 can also be applied to the upper pad 140 . In addition, the upper chuck 140 does not need to be a pin chuck type, but various types such as a vacuum chuck type using a flat pad, an electrostatic chuck type, and the like can be employed.

In the bonding device 41 of the above embodiment, the upper suction cup 140 is fixed to the processing container 100 and the lower suction cup 141 is moved in the horizontal direction and the vertical direction. Move in the vertical direction and fix the lower suction cup 141 to the processing container 100 . However, moving the upper suction cup 140 will increase the size of the moving mechanism, so it is preferable to fix the upper suction cup 140 to the processing container 100 as in the above-mentioned embodiment.

In the bonding system 1 of the above embodiment, after the wafers W _U and W _L are bonded by the bonding device 41, the bonded superposed wafer W _T may be further heated at a predetermined temperature (annealing). deal with). By heat-treating the superimposed wafer _WT , the bonding interface can be bonded more firmly.

As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to this example. It is obvious for those skilled in the art to think of various alterations or modifications within the scope of the idea described in the claims, and the alterations or modifications are certainly considered to belong to the protection scope of the present invention. The present invention is not limited to this example, and various embodiments can be employed. The present invention can also be applied to other substrates such as FPDs (Flat Panel Displays) and mask reticles for photomasks other than wafers.

Explanation of reference signs

1. Bonding system; 2. Input and output station; 3. Processing station; 30. Surface modification device; 40. Surface hydrophilization device; 41. Bonding device; 61. Wafer transport device; 70. Control unit; 140. Upper suction cup; 141, lower suction cup; 180, push member; 190, main body; 191, pin; 192, rib; 193, rib; 194a, first suction area; 194b, second suction area; 200, first pin area ;201, the second pin area; 210, the first pin area; 211, the second pin area; 212, the third pin area; 220, the temperature adjustment mechanism; 230, the inner area; ₂₃₁ , the outer area; circle; W _L , lower wafer; W _T , overlapping wafer.

Claims (12)

1. A bonding device for bonding substrates to each other, characterized in that, The engaging device includes: a first holding part, which is used to perform vacuum suction on the first substrate to adsorb and hold the first substrate on the lower surface; and the second holding part, which is provided below the first holding part, is used to perform vacuum suction on the second substrate to hold the second substrate on the upper surface by suction, The second holding part has a main body for vacuum suctioning the second substrate and a plurality of pins provided on the main body and in contact with the back surface of the second substrate, The position of the tip of the pin provided at the central portion of the body portion is higher than the position of the tip of the pin provided at the outer peripheral portion of the body portion. 2. The joining device according to claim 1, characterized in that, The main body portion is divided into concentric inner and outer regions, the positions of the top ends of the plurality of pins provided in the inner region become lower toward the radially outer side, the positions of the top ends of the plurality of pins provided in the outer region become lower toward the radially outer side, A variation in the positions of the tips of the plurality of pins with respect to radial distance in the inner region is smaller than a variation in positions of the tips of the plurality of pins in the outer region with respect to radial distance. 3. Engagement device according to claim 1 or 2, characterized in that The bonding device further includes a pushing member provided on the first holding portion for pressing the center portion of the first substrate. 4. Engagement device according to claim 1 or 2, characterized in that the body portion is divided into a plurality of concentric pin regions, In the plurality of pin regions, the intervals between the plurality of pins in the inner pin region are smaller than the intervals between the plurality of pins in the outer pin region. 5. Engagement device according to claim 1 or 2, characterized in that The second holding portion further has a rib concentrically and annularly provided on the main body portion and protruding from the main body portion, The second holding portion may be set to vacuum-suction the second substrate in each of a suction region inside the rib and a suction region outside the rib. 6. Engagement device according to claim 1 or 2, characterized in that The second holding unit further includes a temperature adjustment mechanism for adjusting the temperature of the second substrate held by the second holding unit. 7. A joint system comprising the joint device according to claim 1 or 2, characterized in that: The engagement system includes: a processing station having said engaging means; and The input/output station is capable of holding a plurality of first substrates, a plurality of second substrates, and a plurality of laminated substrates formed by bonding the first substrates and the second substrates, and importing and outputting the first substrates, the second substrates, and the first substrates with respect to the processing station. 2 substrates and overlapping substrates, The processing station includes: A surface modifying device for modifying the surfaces to be bonded of the first substrate and the second substrate; A surface hydrophilization device for hydrophilizing the surfaces of the first substrate and the second substrate modified by the surface modification device; and a transport device for transporting the first substrate, the second substrate, and the overlapped substrate with respect to the surface modification device, the surface hydrophilization device, and the bonding device, In the bonding device, the first substrate and the second substrate whose surfaces have been hydrophilized by the surface hydrophilization device are bonded to each other. 8. A bonding method in which substrates are bonded to each other using a bonding device, characterized in that, The engaging device includes: a first holding part, which is used to perform vacuum suction on the first substrate to adsorb and hold the first substrate on the lower surface; a second holding part, which is provided below the first holding part, and is used to perform vacuum suction on the second substrate to hold the second substrate on the upper surface; and a pushing member, which is provided on the first holding part, and is used to press the central part of the first substrate, The second holding part has a main body for vacuum suctioning the second substrate and a plurality of pins provided on the main body and in contact with the back surface of the second substrate, The position of the tip of the pin provided at the central portion of the main body is higher than the position of the tip of the pin provided at the outer peripheral portion of the main body, The bonding method includes the following steps: a first holding step, in which the first substrate is held by the first holding unit; a second holding step, in which the second substrate is held by the second holding portion such that the center portion of the second substrate protrudes upward; a subsequent arranging step, in which the first substrate held by the first holding unit and the second substrate held by the second holding unit are arranged facing each other; In the subsequent pressing step, the pushing member is lowered to press the central portion of the first substrate and the central portion of the second substrate by the pushing member so that the central portion of the first substrate and the second substrate are pressed. the central portions of the substrates are in abutment; and In the following bonding step, in the state where the center portion of the first substrate and the center portion of the second substrate are brought into contact, the vacuum suction of the first substrate by the first holding portion is stopped, The first substrate and the second substrate are bonded sequentially from the center portion of the first substrate toward the outer peripheral portion. 9. The bonding method according to claim 8, wherein: The main body portion is divided into concentric inner and outer regions, the positions of the top ends of the plurality of pins provided in the inner region become lower toward the radially outer side, the positions of the top ends of the plurality of pins provided in the outer region become lower toward the radially outer side, a variation in the positions of the tips of the plurality of pins relative to a radial distance in the inner region is less than a variation in the positions of the tips of the plurality of pins relative to a radial distance in the outer region, In the second holding step, the second substrate is held along the surface of the second holding portion. 10. The bonding method according to claim 8 or 9, wherein: the main body portion is divided into a plurality of concentric pin regions, In the plurality of pin regions, the intervals between the plurality of pins in the inner pin region are smaller than the intervals between the plurality of pins in the outer pin region, In the pressing step, the central portion of the first substrate and the portion of the second substrate supported by the inner pin region are pressed by the pushing member, so that the central portion of the first substrate and the portion of the second substrate are pressed. The portion of the pin region supported on the inner side is in contact with each other. 11. The bonding method according to claim 8 or 9, wherein: The second holding portion further has a rib concentrically and annularly provided on the main body portion and protruding from the main body portion, The second holding portion can be set to vacuum-suction the second substrate in each of a suction region inside the rib and a suction region outside the rib, In the second holding step, the second substrate is sucked and held in the inner suction region, and then the second substrate is sucked and held in the outer suction region. 12. The bonding method according to claim 8 or 9, wherein: In the bonding step, the first substrate and the second substrate are bonded while the temperature of the second substrate is adjusted by a temperature adjustment mechanism provided in the second holding unit.