JP2023008587A - Joining device and joining method - Google Patents

Abstract

To provide a technique capable of improving precision of positioning between substrates to be joined together.SOLUTION: A joining device has: a first holding part which holds a first substrate; a second holding part which holds a second substrate; and a moving part which moves at least one of the first holding part and second holding part relatively to the other. The joining device further comprises: an imaging unit which images both a first mark formed on the substrate and a second mark formed on the second substrate using light transmitted through the first substrate; and a control part which places the moving part in operation based upon imaging information obtained by the imaging unit.SELECTED DRAWING: Figure 7

Description

TECHNICAL FIELD The present disclosure relates to a bonding apparatus and a bonding method.

Patent Literature 1 discloses a bonding apparatus that bonds an upper substrate held by an upper chuck and a lower substrate held by a lower chuck that is horizontally and vertically movable relative to the upper chuck. there is

Prior to bonding, the bonding apparatus moves the lower chuck to align the horizontal positions of the upper substrate and the lower substrate. In alignment, the bonding apparatus determines the relative position of the upper substrate and the lower substrate based on the image captured by the upper imaging unit fixed to the upper chuck and the image captured by the lower imaging unit fixed to the lower chuck. Position awareness and adjust horizontal position.

JP 2015-095579 A

The present disclosure provides a technique capable of improving the alignment accuracy of substrates to be bonded.

According to one aspect of the present disclosure, there is provided a bonding apparatus that bonds a first substrate and a second substrate, comprising: a first holding section that holds the first substrate; and a second holding section that holds the second substrate. a moving part that relatively moves at least one of the first holding part and the second holding part with respect to the other; A bonding apparatus comprising: an imaging unit that images both a mark and a second mark formed on the second substrate; and a control unit that operates the moving unit based on imaging information captured by the imaging unit. provided.

According to one aspect, it is possible to improve the alignment accuracy of the substrates to be bonded.

1 is a schematic plan view of a joining system according to one embodiment; FIG. 1 is a schematic side view showing an example of a first substrate and a second substrate to be bonded by a bonding system according to one embodiment; FIG. 1 is a schematic side view of a joining system according to one embodiment; FIG. 4 is a flow chart showing a joining method by the joining system according to one embodiment. 1 is a schematic plan view showing an example of a bonding apparatus according to one embodiment; FIG. It is a schematic side view which shows the joining apparatus which concerns on one Embodiment. FIG. 4 is a schematic side view showing an imaging unit, upper chuck, lower chuck, upper wafer, and lower wafer; FIG. 4 is an explanatory diagram illustrating imaging information captured by an imaging unit; 5 is a flow chart showing an example of a bonding method of the bonding apparatus according to one embodiment. FIG. 11 is a schematic side view showing an imaging unit, upper chuck, lower chuck, upper wafer, and lower wafer according to a first modified example; FIG. 11 is a schematic side view showing an imaging unit, upper chuck, lower chuck, upper wafer, and lower wafer according to a second modified example;

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant description may be omitted.

As shown in FIG. 1, a bonding system 1 according to an embodiment of the present disclosure transports a first substrate W1 and a second substrate W2, and bonds the first substrate W1 and the second substrate W2 in a bonding device 41. Thus, the bonding substrate T is produced. In FIG. 1, the X-axis direction, Y-axis direction and Z-axis direction of the joining system 1 are directions perpendicular to each other, the X-axis direction and Y-axis direction are horizontal directions, and the Z-axis direction is vertical direction. .

The bonding system 1 comprises a loading/unloading station 2 for a first substrate W1 and a second substrate W2, and a processing station 3 for processing the first substrate W1 and the second substrate. The loading/unloading station 2 and the processing station 3 are installed adjacent to each other along the Y-axis direction and continuously.

At least one of the first substrate W1 and the second substrate W2 bonded by the bonding system 1 is a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer on which a plurality of electronic circuits are formed. Compound semiconductor wafers are, but not limited to, GaAs wafers, SiC wafers, GaN wafers, or InP wafers, for example. Glass substrates may be used instead of semiconductor substrates for the first substrate W1 and the second substrate W2. The other of the first substrate W1 and the second substrate W2 may be a bare wafer on which no electronic circuit is formed.

The first substrate W1 and the second substrate W2 are formed as discs having substantially the same shape (same diameter). As shown in FIG. 2, the bonding system 1 places the second substrate W2 on the Z-axis negative direction side (vertical direction lower side) of the first substrate W1, and bonds the first substrate W1 and the second substrate W2. . Therefore, hereinafter, the first substrate W1 may be called "upper wafer W1", the second substrate W2 may be called "lower wafer W2", and the bonded substrate T may be called "bonded wafer T". Further, hereinafter, of the plate surfaces of the upper wafer W1, the plate surface on the side to be bonded to the lower wafer W2 is referred to as a "bonded surface W1j", and the plate surface on the opposite side of the bonded surface W1j is referred to as a "non-bonded surface W1n". It says. Among the plate surfaces of the lower wafer W2, the plate surface on the side bonded to the upper wafer W1 is referred to as a "bonded surface W2j", and the plate surface opposite to the bonded surface W2j is referred to as a "non-bonded surface W2n".

As shown in FIG. 1 , the loading/unloading station 2 includes a mounting table 10 and a transport area 20 . The mounting table 10 has a plurality of mounting plates 11 . Cassettes C1, C2, and C3 that accommodate a plurality of (for example, 25) substrates in a horizontal state are mounted on each of the mounting plates 11, respectively. Cassette C1 is a cassette that accommodates upper wafer W1, cassette C2 is a cassette that accommodates lower wafer W2, and cassette C3 is a cassette that accommodates bonded wafer T. As shown in FIG. In the cassettes C1 and C2, the upper wafer W1 and the lower wafer W2 are accommodated with the bonding surfaces W1j and W2j facing upward, respectively.

The transfer area 20 is installed between the mounting table 10 and the processing station 3 . The transport area 20 includes a transport path 21 extending in the X-axis direction and a transport device 22 movable along the transport path 21 . The conveying device 22 is movable in the Y-axis direction and can be turned (rotated by θ) on a horizontal plane. , the upper wafer W1, the lower wafer W2 and the bonded wafer T are transferred.

Needless to say, the number of mounting plates 11 mounted on the mounting table 10 and the number of cassettes C1 to C3 are not particularly limited. In addition to the cassettes C1, C2, and C3, the mounting table 10 may also have a cassette (not shown) for recovering the defective substrate.

The processing station 3 includes a first processing block G1 on the positive side of the X-axis and a second processing block G2 on the negative side of the X-axis. The processing station 3 also includes a third processing block G3 on the positive Y-axis side (between the loading/unloading station 2 and the first processing block G1 and the second processing block G2).

Further, the processing station 3 has a transfer area 60 having a transfer device 61 in an area surrounded by the first to third processing blocks G1 to G3. The transport device 61 has, for example, a transport arm that can rotate in the horizontal direction (X-axis direction and Y-axis direction), the vertical direction (Z-axis direction), and the horizontal plane (rotate θ). The transfer device 61 moves within the transfer region 60 and transfers the upper wafer W1, the lower wafer W2 and the bonding wafers W1, W2 and W2 to the devices in the first processing block G1, the second processing block G2 and the third processing block G3 adjacent to the transfer region 60. A wafer T is transferred.

The first processing block G1 includes, for example, a surface modification device 33 and a surface hydrophilization device 34 . Surface modification device 33 modifies bonding surface W1j of upper wafer W1 and bonding surface W2j of lower wafer W2. The surface hydrophilizing device 34 hydrophilizes the modified bonding surface W1j of the upper wafer W1 and the modified bonding surface W2j of the lower wafer W2.

As shown in FIG. 3, the second processing block G2 includes, for example, a bonding device 41, a first temperature adjustment device 42, and a second temperature adjustment device 43. As shown in FIG. The bonding device 41 bonds the hydrophilized upper wafer W1 and the lower wafer W2 (see also FIG. 2) to fabricate a bonded wafer T. FIG. The first temperature adjustment device 42 adjusts the temperature distribution of the upper wafer W1 before bonding (before contact with the lower wafer W2). The second temperature adjustment device 43 adjusts the temperature distribution of the lower wafer W2 before bonding (before contact with the upper wafer W1). In addition, in the present embodiment, the first temperature adjustment device 42 and the second temperature adjustment device 43 are provided separately from the bonding device 41 , but may be provided as part of the bonding device 41 .

In the third processing block G3, for example, a first position adjustment device 51, a second position adjustment device 52, and transition devices 53 and 54 are stacked in order from the Z-axis positive direction side toward the Z-axis negative direction side. . The installation location of each device in the third processing block G3 is not limited to the illustrated example. The first position adjusting device 51 adjusts the horizontal orientation of the upper wafer W1 by rotating the upper wafer W1 on the horizontal plane, and also flips the upper wafer W1 upside down so that the bonding surface W1j of the upper wafer W1 faces downward. do. The second position adjusting device 52 adjusts the horizontal posture of the lower wafer W2 by rotating the lower wafer W2 on the horizontal plane. Upper wafer W<b>1 is temporarily placed on transition device 53 . Also, the lower wafer W2 and the bonded wafer T are temporarily placed on the transition device 54 . In addition, in the present embodiment, the first position adjustment device 51 and the second position adjustment device 52 are provided separately from the bonding device 41 , but may be provided as part of the bonding device 41 .

Returning to FIG. 1, the joining system 1 includes a control device 90 that controls the operation of the entire system. The control device 90 is a control computer having one or more processors 91, memory 92, input/output interfaces and electronic circuits (not shown). One or more processors 91 are a combination of one or a plurality of CPUs, ASICs, FPGAs, circuits made up of a plurality of discrete semiconductors, etc., and execute programs stored in memory 92 . The memory 92 includes non-volatile memory and volatile memory, and forms the storage section of the controller 90 .

Next, the joining method of the joining system 1 according to the embodiment will be described with reference to FIG. 4 . In the bonding method, an operator or a transfer robot (not shown) transfers a cassette C1 containing a plurality of upper wafers W1, a cassette C2 containing a plurality of lower wafers W2, and an empty cassette C3 to the loading/unloading station 2. is mounted on the mounting table 10 of the.

The bonding system 1 transports the upper wafer W1 in the cassette C1 by the transport device 22 and the transport device 61 . Specifically, the transfer device 22 takes out the upper wafer W1 from the cassette C1 and transfers it to the transition device 53 of the third processing block G3. After that, the transfer device 61 takes out the upper wafer W1 from the transition device 53 and transfers it to the surface modification device 33 of the first processing block G1.

Then, the bonding system 1 uses the surface modification device 33 to modify the surface of the upper wafer W1 (step S1). The surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 with the bonding surface W1j facing upward. After step S<b>1 , the transfer device 61 takes out the upper wafer W<b>1 from the surface modification device 33 and transfers it to the surface hydrophilization device 34 .

The bonding system 1 hydrophilizes the surface of the upper wafer W1 by the surface hydrophilization device 34 (step S2). The surface hydrophilizing device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 with the bonding surface W1j facing upward. After that, the transfer device 61 takes out the upper wafer W1 from the surface hydrophilization device 34 and transfers it to the first position adjustment device 51 of the third processing block G3.

The bonding system 1 adjusts the posture of the upper wafer W1 on the horizontal plane by rotating the upper wafer W1 using the first position adjusting device 51, and turns the upper wafer W1 upside down (step S3). Thereby, the notch of the upper wafer W1 is oriented in a predetermined direction, and the bonding surface W1j of the upper wafer W1 is oriented downward. After that, the transfer device 61 takes out the upper wafer W1 from the first position adjustment device 51 and transfers it to the first temperature adjustment device 42 of the second processing block G2.

The bonding system 1 performs temperature control of the upper wafer W1 by the first temperature control device 42 (step S4). The adjustment of the temperature of the upper wafer W1 is performed with the bonding surface W1j of the upper wafer W1 facing downward. After that, the transfer device 61 takes out the upper wafer W<b>1 from the first temperature adjustment device 42 and transfers it to the bonding device 41 .

Also, the bonding system 1 performs the process on the lower wafer W2 in parallel (before or after the time) with the above-described process on the upper wafer W1. The bonding system 1 transports the lower wafer W2 in the cassette C2 by the transport device 22 and the transport device 61. As shown in FIG. First, the transfer device 22 takes out the lower wafer W2 in the cassette C2 and transfers it to the transition device 54 of the third processing block G3 of the processing station 3. As shown in FIG. Thereafter, the transfer device 61 takes out the lower wafer W2 from the transition device 54 and transfers it to the surface modification device 33 of the first processing block G1.

The bonding system 1 uses the surface modification device 33 to modify the surface of the lower wafer W2 (step S5). The surface modification device 33 modifies the surface of the bonding surface W2j of the lower wafer W2 with the bonding surface W2j facing upward. After that, the transfer device 61 takes out the lower wafer W<b>2 from the surface modification device 33 and transfers it to the surface hydrophilization device 34 .

Then, the bonding system 1 hydrophilizes the surface of the lower wafer W2 by the surface hydrophilization device 34 (step S6). The surface hydrophilization device 34 hydrophilizes the joint surface W2j with the joint surface W2j facing upward. After that, the transfer device 61 takes out the lower wafer W2 from the surface hydrophilization device 34 and transfers it to the second position adjustment device 52 of the third processing block G3.

The posture of the lower wafer W2 on the horizontal plane is adjusted by rotating the lower wafer W2 with the bonding system 1 and the second position adjusting device 52 (step S7). Thereby, the notch of the lower wafer W2 is oriented in a predetermined direction. After that, the transfer device 61 takes out the lower wafer W2 from the second position adjustment device 52 and transfers it to the second temperature adjustment device 43 of the second processing block G2.

The bonding system 1 performs temperature control of the lower wafer W2 by the second temperature control device 43 (step S8). The adjustment of the temperature of the lower wafer W2 is performed with the bonding surface W2j of the lower wafer W2 facing upward. After that, the transfer device 61 takes out the lower wafer W<b>2 from the second temperature adjustment device 43 and transfers it to the bonding device 41 .

Then, the bonding system 1 bonds the upper wafer W1 and the lower wafer W2 by the bonding device 41 to manufacture a bonded wafer T (step S9: bonding process). Thereafter, the transfer device 61 takes out the bonded wafer T from the bonding device 41 and transfers it to the transition device 54 of the third processing block G3. Finally, the transfer device 22 takes out the bonded wafer T from the transition device 54 and transfers it to the cassette C3 on the mounting table 10 . Thereby, a series of processing of the joining system 1 is completed.

Note that the joining system 1 does not have to perform all steps S1 to S9 in the joining method. For example, the joining system 1 may not perform steps S4 and S8. Alternatively, the joining system 1 may perform processes other than steps S1 to S9.

Next, an example of the joining device 41 will be described with reference to FIGS. 5 and 6. FIG. The joining device 41 has a box-shaped housing 100 . The housing 100 has a loading/unloading port (not shown) and an opening/closing shutter for opening/closing the loading/unloading port (not shown) on a side wall on the transport area 60 side (X-axis positive direction side). The transport device 61 (see FIG. 1) loads and unloads the upper wafer W1, the lower wafer W2, and the bonded wafer T through the loading/unloading port while the open/close shutter is open.

The bonding apparatus 41 includes an upper chuck 110 (first holding section), a lower chuck 120 (second holding section), a moving section 130 , a gas supply section 140 and an exhaust section 150 inside the housing 100 . These components are supported by the housing 100 itself or a support frame 101 provided inside the housing 100 . Furthermore, the joining device 41 has a control section 190 that controls each component within the joining device 41 . The control unit 190 is communicably connected to the control device 90 and operates based on commands from the control device 90 . Note that the bonding device 41 may have the same function as the control unit 190 in the control device 90 and may be configured such that the control device 90 directly controls the bonding device 41 .

The support frame 101 includes a base 102 , a plurality of pillars 103 projecting upward from the top surface of the base 102 , and an upper frame 104 fixed to the upper ends of the plurality of pillars 103 . The upper frame 104 supports the upper chuck 110 from above.

The upper chuck 110 has a planar circular holding surface 111 that holds the upper wafer W1. The upper chuck 110 includes a plurality of suction tubes (not shown) on the holding surface 111 and a vacuum pump (not shown) connected to each suction tube. The upper chuck 110 sucks and holds the upper surface (non-bonded surface W1n) of the upper wafer W1 on the holding surface 111 by the operation of the vacuum pump.

The upper chuck 110 also includes a pressing portion 112 that presses down the upper wafer W1 to bring it into contact with the lower wafer W2 during bonding. The pushing portion 112 is provided at the center position of the holding surface 111 . The pushing portion 112 has a pushing pin 113 and an outer cylinder 114 that serves as a lifting guide for the pushing pin 113 . The push pins 113 are protruded from the holding surface 111 of the upper chuck 110 by a drive unit (not shown) incorporating a motor, for example, to push down the upper wafer W1.

The upper chuck 110 is installed on the upper frame 104 via an upper chuck moving mechanism 116 . The upper chuck moving mechanism 116 vertically moves the upper chuck 110 up and down. Therefore, the upper wafer W1 held by the upper chuck 110 is also displaced integrally. The moving distance of the upper chuck 110 by the moving mechanism 116 for the upper chuck is shorter than the moving distance of the moving unit 130 described later, and the upper chuck 110 is moved within a range of several nanometers to several millimeters, for example.

On the other hand, the lower chuck 120 is provided below the upper chuck 110 and has a planar circular holding surface 121 for holding the lower wafer W2. The lower chuck 120 includes a plurality of suction tubes (not shown) on the holding surface 121 and a vacuum pump (not shown) connected to each suction tube. The lower chuck 120 sucks and holds the lower surface (non-bonded surface W2n) of the lower wafer W2 on the holding surface 121 by the operation of the vacuum pump.

The moving part 130 of the bonding device 41 moves the lower chuck 120 horizontally (X-axis direction and Y-axis direction) and vertically (Z-axis direction). For example, the moving part 130 includes a first moving part 131 that moves the lower chuck 120 in the X-axis direction, a second moving part 132 that moves the lower chuck 120 in the Y-axis direction, and a lower chuck 120 in the Z-axis direction. and a third moving unit 133 that causes the Further, the moving part 130 has a .theta. direction moving part (not shown) that rotates the lower chuck 120 on the horizontal plane (.theta. rotation).

The first moving part 131 has a pair of first rails 131a extending in the X-axis direction and a first movable body 131b that moves on the pair of first rails 131a. The first moving part 131 has the third moving part 133 fixed to the first movable body 131b.

The second moving part 132 has a pair of second rails 132a extending in the Y-axis direction and a second movable body 132b that moves the pair of second rails 132a. The second moving part 132 mounts the first moving part 131 on the second movable body 132b. That is, the first moving part 131 and the second moving part 132 constitute a horizontal moving part that horizontally moves the lower wafer W2.

The third moving unit 133 includes a motor 133a and a movable base 133b that moves up and down by driving the motor 133a. The third moving part 133 mounts the lower chuck 120 on the movable table 133b. That is, the third moving section 133 constitutes a vertical moving section that moves the lower wafer W2 in the vertical direction.

By moving the lower chuck 120 in the X-axis direction and the Y-axis direction, the moving unit 130 moves the upper wafer W1 held by the upper chuck 110, the lower wafer W2 held by the lower chuck 120, align the horizontal position of the Further, the moving unit 130 moves the lower chuck 120 in the Z-axis direction to align the vertical positions of the upper wafer W1 and the lower wafer W2.

It should be noted that the moving section 130 only needs to be able to relatively move the upper chuck 110 and the lower chuck 120 in the X-axis direction, the Y-axis direction, and the Z-axis direction. Therefore, the moving part 130 may be provided on the upper chuck 110 or may be provided on both the upper chuck 110 and the lower chuck 120 . Alternatively, the moving part 130 may include a part of the first moving part 131 , the second moving part 132 , the third moving part 133 , and the θ-direction moving part in the upper chuck 110 and the rest in the lower chuck 120 . .

The transfer device 61 enters directly below the upper chuck 110 when transferring the upper wafer W<b>1 to the upper chuck 110 . Further, the transfer device 61 enters right above the lower chuck 120 when transferring the lower wafer W2 to the lower chuck. Before the transfer device 61 enters the bonding device 41 , the bonding device 41 moves the lower chuck 120 to a substrate transfer position spaced horizontally and vertically from the upper chuck 110 .

The substrate transfer position is a position where the lower chuck 120 receives the lower wafer W<b>2 from the transfer device 61 and transfers the bonded wafer T to the transfer device 61 . The bonding system 1 unloads the bonded wafer T manufactured by the n (n is a natural number equal to or greater than 1) bonding at the substrate delivery position, and loads the upper wafer W1 and the lower wafer W2 to be bonded by the n+1 bonding. and in succession. Then, the bonding system 1 moves the lower chuck 120 between the substrate delivery position and the bonding position by the moving unit 130 .

The bonding position is a position where the upper wafer W1 and the lower wafer W2 overlap each other in plan view, and the upper wafer W1 and the lower wafer W2 face each other with a gap in the vertical direction. At the bonding position, the vertical gap between the upper wafer W1 and the lower wafer W2 is narrower than the substrate transfer position, and this gap is set to, for example, about 10 μm to 100 μm. At the bonding position, the bonding device 41 bonds the upper wafer W1 and the lower wafer W2 by dropping the upper wafer W1 onto the lower wafer W2.

The gas supply unit 140 of the bonding apparatus 41 supplies the inside of the housing 100 with gas adjusted to a set temperature. The gas is, for example, an inert gas such as dry air, nitrogen gas, argon gas. The gas supply unit 140 is, for example, an FFU (Fan Filter Unit) and supplies purified gas. The set temperature is, for example, normal temperature of about 23°C.

The gas supply unit 140 is connected to a gas supply device provided outside the housing 100 . The gas supply device includes a gas supply source 143, a valve 142, a temperature controller 141, and a temperature sensor 149 in order from upstream to downstream of the pipe. A temperature sensor 149 measures the temperature of the gas and outputs the measured temperature to the controller 190 . The controller 190 controls the temperature adjuster 141 so that the temperature measured by the temperature sensor 149 becomes the set temperature. The gas supply unit 140 may supply gas adjusted to the set humidity.

The gas supply unit 140 is provided on the side surface 100a on the Y-axis negative direction side among the plurality of side surfaces of the housing 100, and discharges gas in the Y-axis positive direction side. The exhaust unit 150 is provided on the side surface 100b on the Y-axis positive direction side, which faces the side surface 100a to which the gas supply unit 140 is attached, among the plurality of side surfaces of the housing 100 . The exhaust unit 150 is connected to a suction device (not shown) such as a vacuum pump, and exhausts the inside of the housing 100 using the suction force of the suction device. The gas supply section 140 and the exhaust section 150 form a side flow inside the housing 100 . In this embodiment, bonding is performed under atmospheric pressure, but bonding may be performed under vacuum.

The bonding apparatus 41 includes a plurality of (two in the present embodiment) imaging units 160 for aligning the upper wafer W1 and the lower wafer W2 when bonding the upper wafer W1 and the lower wafer W2. . The control unit 190 of the bonding apparatus 41 receives imaging information captured by each imaging unit 160, calculates the moving direction and amount of movement of the moving unit 130 based on each imaging information, and causes the moving unit 130 to operate.

Each imaging unit 160 is arranged above the upper chuck 110 by being fixed to the upper frame 104 inside the housing 100 . Each imaging unit 160 emits emitted light (electromagnetic waves) having a wavelength that can pass through the upper wafer W1, and images each of the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. The emitted light that can pass through the upper wafer W1 includes, for example, infrared rays, X-rays, etc. As the infrared rays, it is preferable to use those having a wavelength of 8 μm to 12 μm, which easily penetrates silicon. It is preferable that the wavelength and amount of emitted light are appropriately set according to the material, structure, etc. of the upper wafer W1.

The installation position of the imaging unit 160 is not limited to the upper chuck 110 side (above the upper chuck 110), and may be the lower chuck 120 side (below the lower chuck 120). By arranging the imaging unit 160 only on one side of the upper chuck 110 and the lower chuck 120, the bonding device 41 can increase the degree of freedom in the structure of the other side. For example, the joining device 41 can give the lower chuck 120 where the imaging unit 160 is not arranged a deformation function, a VAC-ZONE control function, and the like.

The two imaging units 160 are provided at positions equidistant (predetermined distance) apart along the Y-axis direction with the center of the upper chuck 110 (pressing portion 112) as a base point. Based on the imaging information of the two imaging units 160, the control unit 190 adjusts the horizontal X-axis position, Y-axis position, and θ position (rotational position) of the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. angle) and the like can be recognized. Therefore, the control section 190 can operate the .theta.-direction moving section based on each imaging information to align the .theta.-positions of the upper wafer W1 and the lower wafer W2. The number of imaging units 160 included in the bonding device 41 is not particularly limited, and may be one or three or more.

As shown in FIG. 7, the upper chuck 110 passes through every plurality (two) of imaging units 160 in order to pass emitted light from the imaging units 160 and reflected light from the upper wafer W1 or the lower wafer W2. It has a window 115 . Each through window 115 faces the non-bonding surface W1n of the upper wafer W1 while the upper chuck 110 holds the upper wafer W1.

The imaging unit 160 includes a case 161 , an imaging unit 162 installed in the case 161 , and an objective lens 166 provided at the tip (light entrance/exit port 165 ) in the case 161 . Further, the imaging unit 162 of the imaging unit 160 according to this embodiment has a first imaging unit 163 that images the upper wafer W1 and a second imaging unit 164 that images the lower wafer W2.

The case 161 is formed in a cylindrical shape that is longer in the Z-axis direction than the upper chuck 110, and accommodates each component of the imaging unit 160 inside. The case 161 is arranged to position the first imaging unit 163 and the second imaging unit 164 at different positions (positions orthogonal to each other) so that the light receiving axis of the first imaging unit 163 and the light receiving axis of the second imaging unit 164 are orthogonal to each other. is fixed to Specifically, the case 161 holds the first imaging unit 163 so that the light receiving axis of the first imaging unit 163 extends in the vertical direction (Z-axis direction), and the light receiving axis of the second imaging unit 164 extends in the horizontal direction (main direction). In the embodiment, the second imaging unit 164 is held along the Y-axis direction).

The imaging unit 160 forms a light guide path 167 in the case 161 that guides light to each of the first imaging section 163 and the second imaging section 164 . The inner wall of the case 161 forming the light guide path 167 may be formed with a smooth inner peripheral surface, and may be formed in various shapes to reduce stray light. Further, the light guide path 167 communicates with a main optical path 167a extending linearly in the vertical direction inside the case 161 and a middle position of the main optical path 167a in the Z-axis direction, and extends linearly in the horizontal direction. and an existing optical path 167b.

The main optical path 167 a communicates with the entrance/exit light port 165 at the tip of the case 161 . Light from the upper wafer W1 and the lower wafer W2 enters the main optical path 167a through the light entrance/exit port 165. As shown in FIG. The main optical path 167a has one objective lens 166 near the entrance/exit light port 165, and a half mirror 168 (beam splitter) at the connection position of the optical path 167b.

The imaging unit 160 also has an output optical path 169 that extends in parallel with the main optical path 167 a along the vertical direction, and is equipped with a light source 170 that emits output light to the output optical path 169 . The type of the light source 170 is not particularly limited as long as it can emit light having a wavelength that can pass through the upper wafer W1. For example, a light emitting diode, a semiconductor laser, or the like can be applied. The output optical path 169 merges with the optical waveguide 167 on the distal end side and shares the objective lens 166 . The imaging unit 160 according to this embodiment has a structure in which emitted light is emitted to the upper wafer W1 and the lower wafer W2 and the reflected light is received. A structure for receiving transmitted light may also be used. In this case, imaging unit 160 may include light source 170 in lower chuck 120 and objective lens 166 at a position opposite light source 170 with upper wafer W1 and lower wafer W2 interposed therebetween.

The first imaging unit 163 is provided at the extended end (the proximal end of the case 161) on the side opposite to the light entrance/exit port 165 in the main optical path 167a. The first imaging unit 163 receives the reflected light that has passed through the half mirror 168 through the main optical path 167 a from the light entrance/exit port 165 .

The first imaging section 163 is a camera having a light receiving section (not shown) facing the entrance/exit light opening 165 of the main optical path 167a. A photodiode, a phototransistor, a photo IC, or the like is applied to the light-receiving unit, and receives reflected light reflected by the bonding surface W1j of the upper wafer W1. The first imaging unit 163 preferably applies equipment with high magnification and high numerical aperture (NA). In this case, the focal range of the first imaging unit 163 is narrowed. The range in which the first imaging unit 163 is focused is, for example, several tens of nanometers to several micrometers. However, since the bonding surface W1j of the upper wafer W1 is in focus and the lower wafer W2 is out of focus, the bonding surface W1j of the upper wafer W1 can be continuously monitored.

The bonding device 41 can adjust the focus of the first imaging unit 163 by vertically moving the upper chuck 110 holding the upper wafer W1. Further, the bonding apparatus 41 arranges the first mark M1 formed on the bonding surface W1j of the upper wafer W1 so as to face the through window 115 when holding the upper wafer W1 on the upper chuck 110 . This enables the first imaging section 163 to capture an image of the first mark M1 based on the reception of the reflected light.

FIG. 8 is an explanatory diagram illustrating imaging information of the imaging unit 160. As shown in FIG. 8A is a schematic diagram of the first imaging information I1 of the first mark M1, FIG. 8B is a schematic diagram of the second imaging information I2 of the second mark M2, and FIG. FIG. 8D is a schematic diagram when the second mark M2 moves, and FIG. 8D is a schematic diagram when the first mark M1 and the second mark M2 match.

An appropriate configuration is applied to the first mark M1 so as to be disposed in the through window 115 of the upper chuck 110 on the bonding surface W1j of the upper wafer W1. For example, as the first mark M1, an element (circuit wiring, element, etc.) provided on the joint surface W1j and reflecting emitted light can be used. As a result, the emitted light is reflected by the first mark M1, and the first mark M1 is mapped on the first imaging information I1 (see FIG. 8A). Note that the upper wafer W1 may be provided in advance with the first marks M1 dedicated to alignment.

On the other hand, as shown in FIG. 7, the spectral path 167b is perpendicular to the axis of the main optical path 167a and extends shorter than the main optical path 167a. The second imaging section 164 is provided at the extended end on the side opposite to the half mirror 168 in the optical path 167b. The second imaging section 164 receives the light reflected by the half mirror 168 through the spectral path 167b.

The second imaging section 164 is a camera having a light receiving section (not shown) that faces the connection portion (half mirror 168) between the optical path 167b and the main optical path 167a. A photodiode, a phototransistor, a photo IC, or the like is applied to the light-receiving unit, similarly to the first imaging unit 163, and receives reflected light reflected by the bonding surface W2j of the lower wafer W2. The second imaging unit 164 may also employ a device with a high magnification and a high numerical aperture (NA), and the same type of device as the first imaging unit 163 can be employed. As a result, the focused range of the second imaging unit 164 is narrowed (for example, the range is several tens of nanometers to several micrometers). However, since the bonding surface W2j of the lower wafer W2 is focused and the focus is shifted from the upper wafer W1, the bonding surface W2j of the lower wafer W2 is continuously monitored while suppressing the imaging of the upper wafer W1. It becomes possible to Note that different devices may be applied to the first imaging unit 163 and the second imaging unit 164 .

The image pickup unit 160 adjusts the focus of the second image pickup section 164 using a focus adjustment section 171 which will be described later. The second imaging unit 164 can image the second marks M2 formed on the bonding surface W2j of the lower wafer W2 based on the reception of the reflected light.

The second mark M2 has an appropriate configuration that is positioned to overlap the first mark M1 when the lower wafer W2 is accurately aligned with the upper wafer W1 and bonded. For example, the second mark M2 can use an element (circuit wiring, element, etc.) provided on the joint surface W2j that reflects the emitted light, like the first mark M1. As a result, the emitted light is reflected by the second mark M2, and the second mark M2 is mapped onto the second imaging information I2 (see FIG. 8B). Note that the lower wafer W2 may also be provided in advance with the second marks M2 dedicated to alignment.

A biconvex lens, a plano-convex lens, or the like can be applied to the objective lens 166 fixed to the main optical path 167a. The objective lens 166 converges the light emitted from the light source 170 onto the bonding surface W1j and the bonding surface W2j, and condenses the reflected light from the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. In addition to the objective lens 166, the imaging unit 160 may have various configurations for adjusting the reflected light passing through the main optical path 167a. For example, this configuration includes a collimator lens and a filter.

Here, before the upper wafer W1 and the lower wafer W2 are bonded, the first distance of the reflected light from the bonding surface W1j of the upper wafer W1 to the first imaging unit 163, and the distance from the bonding surface W2j of the lower wafer W2. The second distance of the reflected light up to the second imaging section 164 is different from each other. In particular, the second distance fluctuates because the lower wafer W2 moves relative to the upper wafer W1. Therefore, the joining device 41 includes a focus adjustment section 171 that focuses the first imaging section 163 on the first mark M1 and focuses the second imaging section 164 on the second mark M2.

The upper wafer W1 held by the upper chuck 110 is moved in the vertical direction by the upper chuck moving mechanism 116, and the first imaging unit 163 can focus on the movement of the upper wafer W1. Therefore, it can be said that the upper chuck moving mechanism 116 is a part of the focus adjustment section 171 . Note that the focus adjustment unit 171 includes a moving mechanism (not shown) that moves the case 161 (both the first imaging unit 163 and the second imaging unit 164) of the imaging unit 160 instead of the upper chuck moving mechanism 116. may Further, the upper chuck moving mechanism 116 may have a function of moving the upper chuck 110 in the horizontal direction. By performing horizontal alignment, it is possible to arrange the first mark M1 in the center of the image captured by the first imaging unit 163 .

The focus adjustment section 171 also has a second imaging section moving mechanism 172 that moves the second imaging section 164 in the case 161 relative to the main optical path 167a. The second imaging section moving mechanism 172 has a drive source such as a motor, and drive transmission sections such as pulleys, belts, and gears (both not shown), and moves the second imaging section in the direction along the axis of the spectral path 167b. 164 is moved. As a result, the imaging unit 160 horizontally moves the second imaging section 164 relative to the half mirror 168 in the main optical path 167a to change only the second distance.

The control unit 190 is a computer built-in board having one or more processors, memories, input/output interfaces and electronic circuits (not shown). The control unit 190 controls the operation of the bonding device 41 based on commands from the control device 90, aligns the upper wafer W1 and the lower wafer W2, and bonds the upper wafer W1 and the lower wafer W2.

In focusing the first imaging unit 163 and the second imaging unit 164 , the control unit 190 operates the upper chuck moving mechanism 116 while performing imaging by the first imaging unit 163 . Therefore, the focus of the first imaging unit 163 first matches the first mark M1 on the upper wafer W1. After that, the control section 190 stops the operation of the upper chuck moving mechanism 116 and operates the second imaging section moving mechanism 172 while the second imaging section 164 performs imaging. Thereby, the imaging unit 160 can focus the second imaging section 164 on the second mark M2 on the lower wafer W2 while maintaining the focus of the first imaging section 163. FIG.

The bonding device 41 according to this embodiment is basically formed as described above, and the operation thereof will be described below.

The bonding system 1 performs processing (surface modification, hydrophilization, temperature control, etc.) on each of the upper wafer W1 and the lower wafer W2 from step S1 to step S8 in FIG. Then, the bonding system 1 performs a bonding method of bonding the upper wafer W1 and the lower wafer W2 by the bonding device 41 in the bonding process of step S9 in FIG.

As shown in FIG. 9, in carrying out the bonding method, the controller 190 of the bonding device 41 causes the transport device 61 to transport the upper wafer W1 temperature-controlled in step S4, and the upper chuck 110 to hold the upper wafer W1. (Step S101). At this time, the controller 90 of the bonding system 1 operates the transfer device 61 holding the upper wafer W1 to transfer the upper wafer W1 directly below the substrate transfer position (upper chuck 110). The controller 190 causes the upper chuck 110 to vacuum-suck the conveyed upper wafer W1. Since the non-bonding surface W1n of the upper wafer W1 is held by the upper chuck 110 by suction, the bonding surface W1j faces downward (in the direction of the lower chuck 120).

After holding the upper wafer W1, the control unit 190 operates the upper chuck moving mechanism 116 while performing imaging by the first imaging unit 163 of the imaging unit 160, so that the focal point of the first imaging unit 163 is the first mark M1. (Joint surface W1j) (step S102). That is, the upper chuck 110 and the upper wafer W1 are moved in the vertical direction by the upper chuck moving mechanism 116, so that the bonding device 41 can smoothly focus the first imaging unit 163 on the first mark M1. In this step S92, the second imaging unit 164 may stop imaging, or may perform imaging and provide imaging information to the control unit 190 to assist focusing of the first imaging unit 163. good too.

Further, the controller 190 transports the lower wafer W2 temperature-controlled in step S8 by the transport device 61, and holds the lower wafer W2 by the lower chuck 120 (step S103). At this time, the controller 90 of the bonding system 1 operates the transfer device 61 holding the lower wafer W2 to transfer the lower wafer W2 directly above the substrate transfer position (lower chuck 120). The controller 190 causes the lower chuck 120 to vacuum-suck the conveyed lower wafer W2. Since the non-bonding surface W2n of the lower wafer W2 is held by the lower chuck 120 by suction, the bonding surface W2j faces upward (in the direction of the upper chuck 110).

After that, the control unit 190 controls the moving unit 130 to move the lower chuck 120 in the horizontal direction relative to the upper chuck 110, thereby temporarily adjusting the positions of the upper wafer W1 and the lower wafer W2 in the horizontal direction. (step S104). In the temporary position adjustment in the horizontal direction, the control unit 190 moves the lower chuck 120 by a predetermined vector (moving direction and moving amount) from the substrate delivery position without using the imaging information of the imaging unit 160, for example. The predetermined vector is preferably set so that the upper chuck 110 and the lower chuck 120 just overlap in the vertical direction. As a result, the lower chuck 120 moves in a short time, and the upper wafer W1 and the lower wafer W2 face each other in the vertical direction.

With this horizontal temporary position adjustment, the second marks M2 of the lower wafer W2 held by the lower chuck 120 vertically overlap (enter) the through window 115 of the upper chuck 110 (FIG. 8(c)). That is, the first marks M1 on the upper wafer W1 and the second marks M2 on the lower wafer W2 are arranged at a short distance (for example, within a range of several hundred μm or less).

Further, the control unit 190 controls the moving unit 130 to vertically move the lower chuck 120 relative to the upper chuck 110 to place the lower wafer W2 at the bonding position (step S105). As a result, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are arranged at an interval of about 10 μm to 100 μm along the vertical direction.

Then, the control section 190 operates the second imaging section moving mechanism 172 while imaging the second imaging section 164 of the imaging unit 160 to focus the second imaging section 164 on the second mark M2 (bonding surface W2j). ) (step S106). That is, the imaging unit 160 smoothly focuses the second imaging unit 164 on the second mark M2 by moving the second imaging unit 164 in the case 161 in the horizontal direction by the moving mechanism 172 for the second imaging unit. be done. Also, in step S95, the first imaging unit 163 continues to capture the first mark M1.

Based on the first imaging information I1 from the first imaging unit 163 and the second imaging information I2 from the second imaging unit 164, the control unit 190 operates the moving unit 130 to move the first mark M1 and the second mark M2. are adjusted in the horizontal direction (step S107). As shown in FIGS. 8(c) and 8(d), the control unit 190 superimposes the first imaging information I1 and the second imaging information I2 so that they are at the same coordinate position in the final position adjustment. Then, the control unit 190 calculates the moving direction and moving amount of the moving unit 130 from the relative difference between the coordinate positions of the superimposed first mark M1 and second mark M2. Further, the control unit 190 operates the moving unit 130 based on the calculated moving direction and moving amount to horizontally move the lower chuck 120 (lower wafer W2). Note that the control unit 190 monitors the imaging information of the imaging unit 160 even while the lower chuck 120 is moving, and feeds back the relative positions of the first mark M1 and the second mark M2. As a result, the second mark M2, which has been displaced from the first mark M1, moves accurately toward directly below the first mark M1.

After the main position adjustment in the horizontal direction, the bonding apparatus 41 can immediately shift to the process of dropping the upper wafer W1 and bonding it to the lower wafer W2. Specifically, the control unit 190 releases the vacuum suction of the central region of the upper wafer W1, and pushes down the center of the upper wafer W1 with the push pin 113 of the pusher 112 to bring it into contact with the lower wafer W2 (step S108). As a result, a van der Waals force (intermolecular force) is generated between the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2, and the centers of the upper wafer W1 and the lower wafer W2 are bonded. Further, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrogen-bonded by hydrophilic groups (for example, OH groups), and the bonding surfaces W1j and W2j are strongly bonded.

Next, the controller 190 releases the vacuum suction of the peripheral region of the upper wafer W1 (step S109). As a result, the upper wafer W1 drops from the center of the upper wafer W1 toward the periphery, and the bonding of the upper wafer W1 and the lower wafer W2 progresses in order from the center toward the periphery.

At this time, the control unit 190 continues imaging the first mark M1 by the first imaging unit 163 and monitors the first mark M1 in the first imaging information I1 of the first imaging unit 163 . When the first mark M1 disappears from the first imaging information I1, it means that the upper wafer W1 has fallen at the imaging position of the imaging unit 160. FIG. Therefore, the bonding apparatus 41 can monitor the progress of bonding between the upper wafer W1 and the lower wafer W2 based on the first imaging information I1 of the imaging unit 160 . That is, the bonding apparatus 41 can use the imaging information of the imaging unit 160 as a detection sensor for bonding the substrates together, and the conventionally installed propagation sensor or the like can be eliminated or reduced. .

As the upper wafer W1 and the lower wafer W2 advance to the periphery, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are bonded over the entire surface, and a bonded wafer T is obtained. After that, the control unit 190 raises the push pin 113 to its original position.

Here, the bonding apparatus 41 may inspect the bonding state of the upper wafer W1 and the lower wafer W2 based on the second imaging information I2 of the second imaging unit 164. FIG. For example, the control unit 190 moves from a state in which the second mark M2 exists in the second imaged information I2 before joining to a state in which the first mark M1 and the second mark M2 exist in the second imaged information I2 after joining. recognize the state. Then, the control unit 190 determines the bonding state of the upper wafer W1 and the lower wafer W2 based on the relative positions of the first marks M1 and the second marks M2 in the second imaging information I2, the clarity of the first marks M1, and the like. can do.

After manufacturing the bonded wafer T, the bonding device 41 moves the moving unit 130 to move the lower wafer W2 to the substrate delivery position, and delivers the bonded wafer T to the transfer device 61, thereby transferring the bonded wafer T from the bonding device 41 to the transfer device 61. is carried out (step S110).

As described above, the bonding apparatus 41 simultaneously images the first marks M1 of the upper wafer W1 and the second marks M2 of the lower wafer by the imaging unit 160, and moves the upper wafer W1 and the lower wafer W2 relative to each other. Thereby, the upper wafer W1 and the lower wafer W2 can be satisfactorily bonded in a state in which the first marks M1 of the upper wafer W1 and the second marks M2 of the lower wafer W2 are superimposed.

Here, in bonding the upper wafer W1 and the lower wafer W2, it is necessary to align them with high accuracy on the order of several nanometers. Further, when the lower wafer W2 is moved in the vertical direction, it is also displaced in the horizontal direction when viewed in units of nm. That is, the conventional apparatus has a problem that it is difficult to align the upper wafer W1 and the lower wafer W2 with high accuracy.

On the other hand, the bonding apparatus 41 according to the present embodiment captures images of both the first marks M1 and the second marks M2 from the upper chuck 110 side with the image capturing unit 160, so that the upper wafer W1 and the lower wafer W2 are captured at the bonding position. relative position can be well recognized. That is, the bonding apparatus 41 performs relative movement in the horizontal direction based on the first marks M1 and the second marks M2 at bonding positions where the upper wafer W1 and the lower wafer W2 are sufficiently close to each other. Alignment accuracy can be improved. In particular, when the alignment of the first mark M1 and the second mark M2 is completed, the movement of the moving part 130 is stopped, and the bonding process can be started as it is. Further, in the conventional apparatus, the upper chuck 110 and the lower chuck 120 are aligned by measuring the length with a laser measuring device, but in the bonding apparatus 41 having the imaging unit 160, it is possible to perform long-distance highly accurate measurement and movement. is no longer required, eliminating the need to use a laser measuring instrument.

Note that the bonding method by the bonding device 41 is not limited to the processing flow described above, and various modifications can be made. For example, after the temporary position adjustment in step S104 and before moving the lower chuck in the vertical direction relative to the upper chuck in step S105, the bonding apparatus 41 performs the second position adjustment of the second imaging unit 164 in step S106. Focusing on the mark M2 and final position adjustment in step S107 may be performed. After this main position adjustment, the control unit 190 moves the lower wafer W2 in the vertical direction, and at this time, the second imaging unit 164 continues imaging while focusing on the second mark M2. When the second mark M2 is displaced from the first mark M1 during movement in the vertical direction, the control unit 190 appropriately controls the movement of the lower wafer W2 in the horizontal direction so that the first mark M1 and the second mark M2 are moved. The overlap of the two marks M2 may continue to be maintained.

Also, the imaging unit 160 is not limited to the configuration described above, and various modifications can be made. For example, as shown in FIG. 10, an imaging unit 160A according to the first modification differs from the imaging unit 160 described above in that it includes a plurality of light sources 170 (first light source 170a, second light source 170b). Specifically, the first light source 170 a faces the upper chuck 110 through the output optical path 169 at a position adjacent to the light guide path 167 . On the other hand, the second light source 170b is provided in a light source optical path 167c that communicates with the main optical path 167a of the light guide path 167 and extends in a direction orthogonal to the main optical path 167a, and faces the main optical path 167a.

Furthermore, the imaging unit 160A has a plurality of half mirrors 168 (first half mirror 168a, second half mirror 168b) corresponding to the second light source 170b, the first imaging section 163, and the second imaging section 164. The first half mirror 168a has the same position and the same function as the half mirror 168 of the imaging unit 160 described above. The second half mirror 168 b is provided at a position where the light source optical path 167 c intersects with the main optical path 167 a and guides the light emitted from the second light source 170 b to the light entrance/exit port 165 . Further, the second half mirror 168b transmits reflected light reflected from the upper wafer W1 and the lower wafer W2.

One objective lens 166 provided only in the light guide path 167 is arranged in the light entrance/exit port 165 . The objective lens 166 allows the light emitted from the second light source 170b to pass therethrough, thereby illuminating the holding surface 111 of the upper wafer W1 and the holding surface 121 of the lower wafer W2 with pinpoint infrared rays. In this manner, the imaging unit 160A is configured such that the optical axis of the light emitted from the second light source 170b and the optical axis of the reflected light from the upper wafer W1 and the lower wafer W2 overlap, so that the first imaging section 163 and the second imaging section 164 focus range can be brightened more effectively.

The imaging unit 160A also emits infrared rays from the first light source 170a in accordance with the emission of the infrared rays from the second light source 170b. (imaging information) can be obtained. Note that the imaging unit 160A may have a configuration in which only the second light source 170b as the light source 170 is provided in the light guide path 167. FIG.

As shown in FIG. 11, an imaging unit 160B according to the second modification includes one imaging unit 162 at the extending end of a light guide path 167 in a case 161, and an adjustable focus on a light entrance/exit port 165. A fluid lens 180 that is the focus adjustment unit 171 is provided.

The fluid lens 180 electrically performs focusing on the first mark M1 and the second mark M2 by being supplied with power from the current-driven actuator 181 under the control of the control unit 190 . For example, the fluid lens 180 is constructed by filling an optical fluid in a polymer film, and applying pressure to the polymer film by a current-driven actuator 181 changes the curvature of the lens to change the focus in a short time.

Accordingly, the imaging unit 160B can alternately focus one imaging section 162 on each of the first marks M1 and the second marks M2. Therefore, the control section 190 can capture both the first mark M1 and the second mark M2 in a favorable manner and perform accurate alignment in the same manner as the imaging unit 160 described above.

The above-described bonding apparatus 41 captures images of both the first marks M1 and the second marks M2 using the light transmitted through the upper wafer W1 by the imaging units 160, 160A, and 160B. The imaging units 160, 160A, and 160B are arranged on the opposite side (upper side) of the lower wafer W2 with the upper wafer W1 as a reference. Compared to the case where the imaging units are arranged between the upper wafer W1 and the lower wafer W2 as described in Patent Document 1, the imaging units 160, 160A, and 160B are arranged in a state in which the distance between the upper wafer W1 and the lower wafer W2 is narrower. can image both the first mark M1 and the second mark M2. Therefore, it is possible to reduce the alignment operation performed after imaging and before joining, and particularly shorten the moving distance in the vertical direction. Therefore, it is possible to reduce unintended horizontal displacement caused by tilting or distortion of the guide that guides vertical movement. As a result, the accuracy of horizontal alignment between the first marks M1 and the second marks M2 can be improved before bonding. Also, the bonding device 41 can move the upper chuck 110 and the lower chuck 120 relative to each other while confirming the relative positions of the first marks M1 of the upper wafer W1 and the second marks M2 of the lower wafer W2. . Therefore, the bonding apparatus 41 can improve the alignment accuracy between the upper wafer W1 and the lower wafer W2. Note that the imaging units 160, 160A, and 160B may be arranged on the opposite side (below) of the upper wafer W1 with respect to the lower wafer W2. Also in this case, the imaging units 160, 160A, and 160B can image both the first marks M1 and the second marks M2 in a state where the distance between the upper wafer W1 and the lower wafer W2 is narrower than in Patent Document 1.

In addition, the imaging units 160, 160A, and 160B include an objective lens 166 on which light transmitted through the first substrate (upper wafer W1 in this embodiment) is incident, and one or more imaging units on which the light passing through the objective lens 166 forms an image. and a focus adjustment unit 171 that focuses one or more imaging units 162 on both the first mark M1 and the second mark M2 while maintaining the position of the objective lens 166 . Accordingly, the imaging units 160, 160A, and 160B can easily focus the imaging section 162 on both the first mark M1 and the second mark M2 without moving the objective lens 166. FIG.

The one or more imaging units 162 include a first imaging unit 163 that images the first mark M1 and a second imaging unit 164 that images the second mark M2. It has a moving mechanism 172 for the second imaging section that moves the second imaging section 164 relative to the first imaging section 163 while the focus of the section 163 is on the first mark M1. As a result, the bonding apparatus 41 can acquire the first imaging information I1 from the first imaging unit 163 and the second imaging information I2 from the second imaging unit 164 at the same time, and can recognize their relative positions. Alignment can be performed smoothly.

In addition, the first imaging unit 163 and the second imaging unit 164 are provided at mutually different positions, and share a part of the light guide path 167 through which light incident from the upper wafer W1 and the lower wafer W2 passes. A half mirror 168 is provided at a position where the light receiving axis of the first imaging section 163 and the light receiving axis of the second imaging section 164 intersect in the light guide path 167 . As a result, the joining device 41 can stably image the first mark M1 with the first imaging unit 163 and stably image the second mark M2 with the second imaging unit 164 .

The one or more imaging units 162 are configured by one imaging unit 162, and the focus adjustment unit 171 focuses the one imaging unit 162 on each of the first mark M1 and the second mark M2 based on power supply. It has a matching fluid lens 180 . Thus, even if the fluid lens 180 is applied as the focus adjustment unit 171, each of the first marks M1 on the upper wafer W1 and the second marks M2 on the lower wafer W2 can be satisfactorily imaged.

In addition, after bonding the upper wafer W1 and the lower wafer W2, the imaging units 160, 160A, and 160B perform imaging with one or more imaging units 162 focused on the second marks M2, and the control unit 190 controls one or more Based on the imaging information imaged by the imaging unit 162, the bonded state of the upper wafer W1 and the lower wafer W2 is inspected. As a result, the bonding apparatus 41 can easily recognize the bonded state of the bonded wafers T, and can simplify or omit the inspection of the bonded wafers T, for example.

In addition, the imaging units 160, 160A, and 160B perform imaging with one or more imaging units 162 focused on the first marks M1 during bonding of the upper wafer W1 and the lower wafer W2. In the imaging information imaged by the imaging unit 162, the progress of bonding between the upper wafer W1 and the lower wafer W2 is recognized based on the disappearance of the first mark M1. As a result, the bonding apparatus 41 can detect the progress of bonding between the upper wafer W1 and the lower wafer W2, and the propagation sensor and the like can be omitted.

Imaging units 160, 160A, and 160B are arranged on the side opposite to the surface holding upper wafer W1 of upper chuck 110, and through window 115 provided in upper chuck 110, upper wafer W1 is captured. The first mark M1 and the second mark M2 on the lower wafer W2 are imaged. As a result, even if the imaging units 160, 160A, and 160B are installed in the bonding apparatus 41, the movement of the upper chuck 110 and the lower chuck 120 is not hindered, and the lower chuck 120 has a higher degree of freedom, allowing it to perform other functions. can have

The control unit 190 also includes an imaging unit 160 that presses the center of the upper wafer W1 that faces the lower wafer W2 at a distance to join the upper wafer W1 and the lower wafer W2. , 160A and 160B, and when the pressing unit 112 presses the center of the upper wafer W1, the distance between the upper wafer W1 and the lower wafer W2 is the same. interval. As a result, the bonding apparatus 41 can press the upper wafer W1 by the pressing portion 112 immediately after the upper wafer W1 and the lower wafer W2 are aligned in the horizontal direction (after the main position adjustment). can be improved and the efficiency of the joining operation can be improved.

Also, the imaging units 160, 160A, and 160B are provided at positions separated by a predetermined distance from the pressing portion 112 as a reference. The plurality of imaging units 160, 160A, and 160B enable the bonding apparatus 41 to more accurately align the relative positions of the upper wafer W1 and the lower wafer W2.

The upper chuck 110 horizontally holds the upper wafer W1, the lower chuck 120 horizontally holds the lower wafer W2, and the moving unit 130 relatively moves the upper chuck 110 and the lower chuck 120 in the vertical direction. 3 moving part 133, and a first moving part 131 and a second moving part 132 for relatively moving the upper chuck 110 and the lower chuck 120 in the horizontal direction. Only the first moving unit 131 and the second moving unit 132 of the moving unit 130 are operated based on the imaging information captured by the . As a result, after the upper wafer W1 and the lower wafer W2 are aligned in the horizontal direction (after the main position adjustment), there is no need to move in the vertical direction, and positional deviation that may occur during the movement in the vertical direction is avoided. be able to.

Also, the upper wafer W1 held by the upper chuck 110 is arranged above the lower wafer W2 held by the lower chuck 120 . As a result, the bonding apparatus 41 can easily bond the upper wafer W1 and the lower wafer W2 by dropping the upper wafer W1 onto the lower wafer W2 after alignment based on the imaging information of the imaging units 160, 160A, and 160B. can.

It also includes an upper chuck moving mechanism 116 that moves the upper chuck 110 up and down relative to the imaging units 160, 160A, and 160B. By moving the upper chuck moving mechanism 116 up and down, the bonding device 41 can focus one imaging unit 162 out of the plurality of imaging units 162 on the first mark M1 or the second mark M2.

Further, one aspect of the present disclosure is a bonding method of a bonding device 41 that bonds a first substrate (upper wafer W1) and a second substrate (lower wafer W2), wherein the bonding device 41 holds the upper wafer W1. A first holding part (upper chuck 110), a second holding part (lower chuck 120) holding the lower wafer W2, and a moving part 130 that relatively moves at least one of the upper chuck 110 and the lower chuck 120 with respect to the other. and imaging units 160, 160A, and 160B for imaging the first marks M1 formed on the upper wafer W1 and the second marks M2 formed on the lower wafer W2 using light transmitted through the upper wafer W1. , and the joining method is to focus the imaging units 160, 160A, 160B on both the first mark M1 and the second mark M2 to obtain the first image information I1 having the first mark M1 and the second mark M2. and moving the moving unit 130 based on the first imaging information I1 and the second imaging information I2 to align the relative positions of the upper wafer W1 and the lower wafer W2. and a step of bonding the upper wafer W1 and the lower wafer W2 after alignment. Thereby, the bonding method can improve the alignment accuracy of the substrates to be bonded.

The joining device according to the embodiment disclosed this time is illustrative in all respects and is not restrictive. Embodiments are capable of variations and modifications in various forms without departing from the scope and spirit of the appended claims. The items described in the above multiple embodiments can take other configurations within a consistent range, and can be combined within a consistent range.

1 Joining system 41 Joining device 110 Upper chuck 112 Pushing unit 115 Through window 116 Upper chuck moving mechanism 120 Lower chuck 130 Moving units 160, 160A, 160B Imaging unit 162 Imaging unit 163 First imaging unit 164 Second imaging unit 167 Guide Optical path 168 Half mirror 171 Focus adjustment unit 172 Second imaging unit movement mechanism 180 Fluid lens 190 Control unit

Claims (14)

A bonding apparatus for bonding a first substrate and a second substrate,
a first holding part that holds the first substrate;
a second holding part that holds the second substrate;
a moving part that relatively moves at least one of the first holding part and the second holding part with respect to the other;
an imaging unit that images both a first mark formed on the first substrate and a second mark formed on the second substrate using light transmitted through the first substrate;
a control unit that operates the moving unit based on imaging information captured by the imaging unit;
Welding equipment. The imaging unit is
an objective lens into which the light transmitted through the first substrate is incident;
one or more imaging units in which the light passing through the objective lens forms an image;
a focus adjustment unit that focuses the one or more imaging units on both the first mark and the second mark while maintaining the position of the objective lens;
The joining device according to claim 1. The one or more imaging units include a first imaging unit that images the first mark and a second imaging unit that images the second mark,
The focus adjustment section has a movement mechanism for a second imaging section that relatively moves the second imaging section with respect to the first imaging section while the focus of the first imaging section is aligned with the first mark. ,
The joining device according to claim 2. The first imaging unit and the second imaging unit are provided at mutually different positions, and share a part of a light guide path through which light incident from the first substrate and the second substrate passes,
A half mirror is provided in the light guide path at a position where the light receiving axis of the first imaging section and the light receiving axis of the second imaging section intersect,
The joining device according to claim 3. The one or more imaging units are configured by one imaging unit,
The focus adjustment unit has a fluid lens that focuses the one imaging unit on each of the first mark and the second mark based on power supply.
The joining device according to claim 2. The imaging unit performs imaging with the one or more imaging units focused on the second mark after bonding the first substrate and the second substrate,
The control unit inspects the state of bonding between the first substrate and the second substrate based on the imaging information captured by the one or more imaging units.
The joining device according to any one of claims 2 to 5. The imaging unit performs imaging with the one or more imaging units focused on the first mark during bonding of the first substrate and the second substrate;
The control unit recognizes progress of bonding between the first substrate and the second substrate based on disappearance of the first mark in the imaging information captured by the one or more imaging units.
The joining device according to any one of claims 2 to 6. The imaging unit is arranged on the opposite side of the surface of the first holding portion that holds the first substrate, and the imaging unit is arranged on the side of the first holding portion that is arranged on the side opposite to the surface that holds the first substrate. imaging a first mark and the second mark of the second substrate;
The joining device according to any one of claims 1 to 7. a pressing portion that presses the center of the first substrate facing the second substrate with a gap to join the first substrate and the second substrate;
The control unit
a distance between the first substrate and the second substrate when both the first mark and the second mark are imaged by the imaging unit and when the pressing portion presses the center of the first substrate; to the same interval,
The joining device according to any one of claims 1 to 8. A plurality of the imaging units are provided at positions separated by a predetermined distance with respect to the pressing unit,
The joining device according to claim 9. the first holding part horizontally holds the first substrate, the second holding part horizontally holds the second substrate,
The moving part includes a vertical direction moving part that relatively moves the first holding part and the second holding part in a vertical direction, and a moving part that relatively moves the first holding part and the second holding part in a horizontal direction. a horizontal moving part that causes
The control unit operates only the horizontal moving unit among the moving units based on the imaging information captured by the imaging unit.
The joining device according to any one of claims 1 to 10. The first substrate held by the first holding unit is arranged above the second substrate held by the second holding unit,
The joining device according to any one of claims 1 to 11. A moving mechanism that moves the first holding section up and down relative to the imaging unit,
The joining device according to any one of claims 1 to 12. A bonding method for a bonding apparatus for bonding a first substrate and a second substrate, comprising:
The bonding device is
a first holding part that holds the first substrate;
a second holding part that holds the second substrate;
a moving part that relatively moves at least one of the first holding part and the second holding part with respect to the other;
an imaging unit that images a first mark formed on the first substrate and a second mark formed on the second substrate using light transmitted through the first substrate;
The joining method is
obtaining first imaging information having the first mark and second imaging information having the second mark by focusing the imaging unit on both the first mark and the second mark;
moving the moving unit based on the first imaging information and the second imaging information to align the relative positions of the first substrate and the second substrate;
bonding the first substrate and the second substrate after the alignment.

Images