JP2022188313A - Substrate bonding device and method - Google Patents

Abstract

To detect the state of progress of bonding substrates.SOLUTION: A substrate bonding device includes a pair of electrodes 351a arranged to sandwich at least one of substrates 211 and 213, and a detection unit 353a that detects electrostatic properties between two electrodes included in the pair of electrodes. A contact region is formed by bringing parts of the respective substrates into contact with each other, and when the contact region is expanded in the plane direction, the detection unit detects the electrostatic characteristics between the two electrodes included in the pair of electrodes 351a arranged to sandwich at least one of the substrates 211 and 213 to detect the state of the contact area, that is, the bonding process of the substrates.SELECTED DRAWING: Figure 4A

Description

The present invention relates to a substrate bonding apparatus and method.

In the manufacture of electronic devices such as semiconductor devices, the surfaces of two substrates are activated, parts of the activated surfaces are brought into contact to form a contact region, and the contact region is extended in a direction along the bonding surface. A technique of bonding two substrates by enlarging is adopted. Here, since the progress of bonding may change depending on the state of the substrates, etc., a technique for detecting the progress of bonding is required. Therefore, in Patent Document 1, a plurality of light-receiving portions arranged side by side from the position of the contact area in a plan view are used to receive reflected light from one of two substrates to be bonded to each other and from the other of the substrates to perform bonding. An apparatus for detecting progress is disclosed. However, it is necessary to dispose a plurality of light-receiving units in a holder that holds the substrate or a stage that holds the holder, which is inconvenient.
Patent Document 1: JP 2012-191037 A

A first aspect of the present invention provides a substrate bonding apparatus for bonding a first substrate and a second substrate, comprising a pair of substrates arranged to sandwich at least one of the first substrate and the second substrate. A substrate bonding apparatus is provided that includes an electrode and a detection unit that detects an electrostatic property between a pair of electrodes.

In a second aspect of the present invention, there is provided a substrate bonding method for bonding a first substrate and a second substrate, wherein portions of the first substrate and the second substrate are in contact with each other. forming a contact area; enlarging the contact area; and detecting electrostatic properties between a pair of electrodes arranged with at least one of a first substrate and a second substrate interposed therebetween. A substrate lamination method is provided.

It should be noted that the above summary of the invention does not list all the features of the invention. Subcombinations of these feature groups can also be inventions.

1 schematically shows the configuration of a substrate bonding system; 4 shows the surface configuration of substrates to be bonded together by the substrate bonding system. The structure of a bonding apparatus is shown schematically. The structure of a bonding detection apparatus is shown schematically. 4 schematically shows another configuration of the bonding detection device; An example of the arrangement of electrode pairs is shown. 5B shows a modification to the electrode pair arrangement of FIG. 5A. Another example of an arrangement of electrode pairs is shown. 6B shows a modification to the electrode pair arrangement of FIG. 6A. 4 schematically shows a cross-sectional configuration of a holder holding a substrate; 4 schematically shows a cross-sectional configuration of another holder holding a substrate; 4 shows a state of substrates (a state in which two substrates are aligned) in a substrate bonding step; 4 shows the state of the substrates (the state in which the contact regions are formed) in the substrate bonding process. The state of the substrate in the substrate bonding process (the state in which the bonding wave is in progress) is shown. The state of the substrates in the substrate bonding step (the state after bonding) is shown. The electrode shape and the principle of substrate displacement detection are shown. The electrode shape and the principle of substrate displacement detection are shown. An example of a result of substrate displacement detection during the substrate bonding process is shown. Another example of the result of substrate displacement detection during the substrate bonding process is shown. Another principle of electrode shape and substrate displacement detection is shown. Another principle of electrode shape and substrate displacement detection is shown. An example of a result of substrate displacement detection during the substrate bonding process is shown. The electrode shape according to the modification and the principle of displacement detection of the substrate are shown. The electrode shape according to the modification and the principle of displacement detection of the substrate are shown. 4 shows a flow of a substrate bonding procedure. 1 shows one step (substrate loading) of a substrate bonding procedure in a bonding apparatus. 1 shows one step (detection of alignment marks) of a substrate bonding procedure in a bonding apparatus. 1 shows one step (activation of the substrate surface) of the substrate bonding procedure in the bonding apparatus. 1 shows one step (alignment of substrates) of a substrate bonding procedure in a bonding apparatus. 1 shows one step (arrangement of electrode pairs) of a substrate bonding procedure in a bonding apparatus. 1 shows one step (formation of a starting point of bonding) of a substrate bonding procedure in a bonding apparatus. 1 shows one step (unloading of the bonded substrate) of the substrate bonding procedure in the bonding apparatus. A modification of the electrode arrangement and the principle of displacement detection of the substrate are shown. A modification of the electrode arrangement and the principle of displacement detection of the substrate are shown. 1 schematically shows the configuration of a bonding detection device according to a first modified example; 1 schematically shows the configuration of a bonding detection device according to a first modified example; The structure of the bonding detection apparatus based on a 2nd modification is shown roughly. The structure of the bonding detection apparatus based on a 2nd modification is shown roughly.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention.

FIG. 1 schematically shows the configuration of a substrate bonding system 100. As shown in FIG. The substrate bonding system 100 is a group of apparatuses for bonding two substrates together to form a stacked device, and includes a housing 110, a conveying device 140, a control device 150, a bonding device 300, a holder stocker 400, and a pre-aligner 500. Prepare. A substrate 210 to be bonded is housed in a substrate cassette 120 , and a substrate 230 that has been bonded (also referred to as a bonded substrate) is housed in a substrate cassette 130 .

The housing 110 accommodates the conveying device 140, the bonding device 300, the holder stocker 400, and the pre-aligner 500 inside. The inside of the housing 110 is temperature-controlled, for example, kept at room temperature. The substrate cassettes 120 and 130 can be individually and detachably fixed from the outside of the housing 110 . A plurality of substrates 210 can be collectively loaded into the substrate bonding system 100 by the substrate cassette 120 , and a plurality of bonded substrates 230 bonded together by the substrate cassette 130 can be collectively unloaded from the substrate bonding system 100 .

The transport device 140 is a device that holds the substrates 210 and 230 with an extendable and rotatable arm and transports them between the substrate cassettes 120 and 130 and each device in the housing 110 . The transport device 140 transports a single substrate 210, a holder 220, a holder 220 holding the substrate 210, a substrate 230 in which the substrates 210 are laminated and laminated, and the like.

The control device 150 is a device that makes each device of the substrate bonding system 100 cooperate with each other and controls them comprehensively. The control device 150 receives user instructions from the outside and sets manufacturing conditions for manufacturing the bonded substrate 230 . Furthermore, the control device 150 has a user interface that displays the operating state of the substrate bonding system 100 to the outside.

The bonding apparatus 300 forms a contact region between the two substrates 210 in which portions of each substrate are in contact with each other, and enlarges the contact region in a direction along the bonding surface (also referred to as a plane direction). This is an apparatus for forming a bonded substrate 230 by directly bonding two substrates. It should be noted that the fact that the contact area between the substrates 211 and 213 expands and the boundary thereof advances in the planar direction is sometimes expressed as the advancement of the bonding wave. Here, bonding means a state in which terminals provided on the two substrates 210 are electrically connected to each other, and a state in which insulating films formed on the surfaces of the two substrates 210 are bonded to each other. It includes a state in which the substrates 210 are not electrically connected, and both states in which separation of the two substrates 210 is possible and impossible. In order to improve the bonding strength of the two substrates 210, after the two substrates 210 are bonded together, the substrates 210 are preferably carried into a heating apparatus such as an annealing furnace and heated. The configuration and operation of the bonding apparatus 300 will be described later.

Holder stocker 400 accommodates a plurality of holders 220 . The holder 220 is made of a hard material such as alumina ceramics, and has a holding portion that adsorbs the substrate 210 and an edge portion arranged outside the holding portion. Inside the substrate bonding system 100 , the holder 220 sucks and holds the substrate 210 by means of a holding portion, and is handled integrally with the substrate 210 . Accordingly, when the attracting surface of the holding portion is flat, the flatness of the warped or bent substrate 210 can be ensured. After bonding the substrates 210 , when the bonded substrate stack 230 is unloaded from the substrate bonding system 100 , the holder 220 is separated from the bonded substrate stack 230 and stored in the holder stocker 400 again. This allows a small number of holders 220 to be used repeatedly.

The pre-aligner 500 cooperates with the transport device 140 to cause the holder 220 to hold the substrate 210 carried into the substrate bonding system 100 . Also, the pre-aligner 500 may be used when separating the bonded substrate 230 carried out from the bonding apparatus 300 from the holder 220 .

The substrate bonding system 100 can bond unprocessed silicon wafers, compound semiconductor wafers, glass substrates, etc., in addition to substrates 210 on which elements, circuits, terminals, etc. are formed. Also, a circuit board having a circuit formed thereon and an unprocessed board can be bonded together, or substrates of the same type such as circuit boards or unprocessed substrates can be bonded together. Furthermore, the substrate 210 to be bonded may itself be a bonded substrate 230 formed by laminating a plurality of substrates.

FIG. 2 shows the surface structure of a substrate 210 to be bonded by the substrate bonding system 100. As shown in FIG. Substrate 210 has a notch 214 , a plurality of circuit regions 216 and a plurality of alignment marks 218 .

The notch 214 is formed along the periphery of the generally circular substrate 210 and serves as an indicator of the crystal orientation in the substrate 210 . Further, when handling the substrate 210, the arrangement direction of the circuit regions 216 on the substrate 210 can be known by detecting the position of the notch 214. FIG. Further, when circuit regions 216 including different circuits are formed on one substrate 210, the circuit regions 216 can be distinguished using the notch 214 as a reference.

The circuit regions 216 are periodically arranged on the surface of the substrate 210 in the plane direction of the substrate 210 . Each of the circuit regions 216 is provided with a semiconductor device, a wiring, a protective film, and the like, which are formed by a photolithographic technique or the like. In the circuit area 216, pads, bumps, etc., which serve as connection terminals when electrically connecting the substrate 210 to another substrate 210, a lead frame, etc., are also arranged.

Alignment marks 218 are arranged, for example, over scribe lines 212 arranged between circuit regions 216, and are used as indicators when aligning the substrate 210 with another substrate 210 to be laminated.

FIG. 3 schematically shows the structure of the bonding apparatus 300. As shown in FIG. Substrates 211 and 213 are carried into the bonding apparatus 300 while being held by holders 221 and 223, respectively. The bonding apparatus 300 includes a frame 310 , an upper stage 322 , a lower stage 332 , an interferometer 341 , microscopes 324 and 334 , activation devices 326 and 336 and a bonding detection device 350 .

The frame 310 is a member that supports each component of the bonding apparatus 300, and stands on a bottom plate 312 that is placed on a horizontal floor surface (not shown) via an anti-vibration device (not shown). It has a plurality of pillars 314 provided and a top plate 316 supported by the plurality of pillars 314 .

The upper stage 322 is a stage that supports the substrate 211, and is fixed to the top plate 316 of the frame 310 with the holding surface that holds the substrate 211 facing downward. Here, the substrate 211 is held by a holder 221 and is held by a vacuum chuck or an electrostatic chuck on the holding surface via this.

The lower stage 332 is a stage that supports the substrate 213 so as to face the substrate 211 held by the upper stage 322 . The lower stage 332 includes an X-direction driving section 331 arranged on the bottom plate 312 of the frame 310, a Y-direction driving section 333 arranged on the X-direction driving section 331, and a Y-direction driving section 333 arranged to be able to move up and down. A lower stage 332 supporting the substrate 213 is driven in the XY directions, that is, the horizontal direction and the Z-axis direction, that is, the vertical direction. Here, the substrate 213 is held by a holder 223 and is held by a vacuum chuck or an electrostatic chuck on the holding surface on the stage through this.

Here, the X-direction driving section 331 moves on the bottom plate 312 in the X-axis direction. The Y-direction driving section 333 moves on the X-direction driving section 331 in the Y-axis direction. By combining the operations of these drive units, the lower stage 332 moves on the bottom plate 312 in the XY directions. Thereby, the substrate 213 supported on the lower stage 332 can be aligned with the substrate 211 supported on the upper stage 322 .

Also, the elevation driving section 338 ascends and descends in the Z-axis direction with respect to the Y-direction driving section 333 . The lower stage 332 is supported on an elevation drive section 338 . Thereby, the substrate 213 supported by the lower stage 332 can be pressed against the substrate 211 supported by the upper stage 322 .

Note that the X-direction driving section 331 and the Y-direction driving section 333 may be configured as a coarse movement section and a fine movement section. As a result, it is possible to align the substrate 213 supported by the lower stage 332 with high precision and high speed by combining high throughput by the coarse movement section and high precision alignment by the fine movement section.

In addition, a rotation drive section for rotating the lower stage 332 around the Z axis and a swing drive section for swinging the lower stage 332 may be further provided. The substrate 213 held on the lower stage 332 is rotated by the rotation drive section, and the lower stage 332 is made parallel to the upper stage 322 by the swing drive section, thereby improving the alignment accuracy of the substrates 211 and 213. can be done.

The interferometer 341 is a measuring device that measures the position of the lower stage 332 and is fixed to the left support column 314 of the frame 310 as an example. The interferometer 341 projects the measurement light onto a mirror surface provided on the side surface of the lower stage 332 (here, the Y-direction driving unit 333), and detects the reflected light by superimposing it on the reference light (not shown). The horizontal position of stage 332 is measured. The measurement result is supplied to the control device 150 .

The microscope 324 is a detection system for detecting alignment marks on the substrate 213 supported on the lower stage 332, and is fixed downward on the top plate 316 of the frame 310. As shown in FIG. A detection result of the microscope 324 is supplied to the control device 150 .

The microscope 334 is a detection system for detecting alignment marks of the substrate 211 supported on the upper stage 322, and is fixed upward on the upper left side of the lower stage 332 (here, the Y-direction driving unit 333). . A detection result of the microscope 334 is supplied to the control device 150 .

The activation device 326 is a device that generates plasma for cleaning the upper surface of the substrate 213 held on the lower stage 332 , and is fixed downward to the top plate 316 of the frame 310 .

The activation device 336 is a device that generates plasma for cleaning the surface of the substrate 211 supported on the upper stage 322. The activation device 336 is directed upward to the left of the upper surface of the lower stage 332 (here, the Y-direction driving unit 333). is fixed.

The position of the lower stage 332 or the relative positions of the microscopes 324 and 334 can be determined by driving the lower stage 332 to position the microscope 334 directly below the microscope 324, and by positioning the microscopes 324 and 334 relative to each other or to a common index. It can be calibrated by focusing and resetting the measurement coordinates determined by the optical axis of the measurement light of interferometer 341 (see FIG. 13A). The relative positions of the microscopes 324, 334 are also called baselines, and the calibration of such relative positions is also called baseline measurements.

The bonding detection device 350 is a device for detecting the bonding state of the substrates 211 and 213 and includes a plurality of electrodes 351 , an electrode driving device 352 and a detection section 353 .

The plurality of electrodes 351 are electrodes for detecting the position of the substrate 211 in the Z-axis direction, and include at least a pair of electrodes arranged to sandwich the substrates 211 and 213 in a non-contact manner in the planar direction of the substrates 211 and 213. . Here, at least one of the electrode surfaces facing each other of the pair of electrodes has a shape in which the width changes along the direction intersecting the XY direction, that is, the Z-axis direction. In this embodiment, the shape is circular, but the shape is not limited to this, and may be elliptical, triangular, rhombic, trapezoidal, or the like. Accordingly, when the substrate 211 moves in the Z-axis direction, the width or area S of the portion of the electrode facing the substrate 211 changes. (these are collectively referred to as electrostatic properties) that are correlated with each other change. Here, assuming that the capacitance C between the electrodes is predominantly determined by the substrate 211, C=εS/D using the dielectric constant ε and the distance D between the pair of electrodes. The arrangement of the plurality of electrodes 351 will be further described later.

In the case of electrodes having polygonal electrode surfaces such as triangles, rhombuses, and trapezoids, the relationship between the position Z of the substrate 211 in the Z-axis direction and the area S(Z) of the portion of the electrode facing the substrate 211 is linear. Therefore, the linearity of the electrostatic characteristic C between the electrodes with respect to the Z position of the substrate 211 can be obtained. On the other hand, in the case of circular electrodes, the relationship between the Z position of the substrate 211 and the area S(Z) of the electrode facing the substrate 211 is non-linear. may be used to linearize the relationship of the inter-electrode electrostatic characteristic C with respect to Z position.

In the illustrated example, the electrode driving device 352 is a device that moves the plurality of electrodes 351 to the sides of the substrates 211 and 213 and retreats from the sides of the substrates 211 and 213 . The electrode driving device 352 is fixed to the side of the upper stage 322 by the top plate 316 of the frame 310, and drives the plurality of electrodes 351 in the Z-axis direction by, for example, an electromagnetic motor. When the substrate 211 is loaded onto the upper stage 322, the electrode driving device 352 retracts the plurality of electrodes 351 to a position where they do not come into contact with the substrate 211. When the lower stage 332 moves, such as when detecting alignment marks, the electrode driving device 352 , the plurality of electrodes 351 are retracted to a position out of contact with the substrate 213 .

The electrode driver 352 moves the electrodes 351 to the substrate 211 by moving the two electrodes constituting the electrode pair included in the electrodes 351 in directions toward or away from each other, or in directions different from each other. , 213 or retreat from the periphery of the substrates 211 and 213 . Further, the electrode driving device 352 may not move the plurality of electrodes 351 to the sides of the substrates 211 and 213, but may only retreat from the sides.

When the upper stage 322 moves up and down with a sufficient stroke and the microscope 324 has a sufficiently large depth of focus, instead of moving up and down the electrodes 351, the upper stage 332 and the lower stage 332 can be moved up and down. The plurality of electrodes 351 may be moved to the sides of the substrates 211 and 213 and retracted from the sides. In such a case, the electrode driver 352 may not be provided. Further, it is not necessary to move all of the plurality of electrodes 351, and some of the plurality of electrodes 351 may be moved.

The detection unit 353 detects electrostatic characteristics between at least one pair of electrodes included in the plurality of electrodes 351 . The electrostatic property can be detected, for example, by inputting an AC voltage between a pair of electrodes, detecting an AC current output from this, and calculating the impedance from the ratio of the AC voltage and the current. A detection result is transmitted to the control device 150 . As a result, the position and movement of the substrate 211 in the Z-axis direction can be detected, and the state such as the expansion process of the contact area in bonding the substrates 211 and 213 can be detected. The detection unit 353 may be provided for each electrode pair, or may be provided commonly for all electrode pairs.

In the example shown in FIG. 4A, the plurality of electrodes 351 includes a plurality of pairs of two electrodes, an electrode pair 351A having two electrodes 351a, an electrode pair 351B having two electrodes 351b, and two electrodes 351c. , an electrode pair 351D having two electrodes 351d, and an electrode pair 351E having two electrodes 351e. Incidentally, as shown in FIG. 4A, detectors 353a to 353e may be provided for each of the electrode pairs 351A to 351E. In such a case, the detection units 353a to 353e are each independently connected between the two electrodes 351a to 351e that constitute the corresponding electrode pairs of the electrode pairs 351A to 351E (for example, the detection unit 353a detects two electrodes that constitute the electrode pair 351A). between two electrodes 351a), and transmits the detection result to the control device 150. FIG. Also, one detection unit 353 may be provided for each of the plurality of electrode pairs 351A to 351E. In such a case, the detection unit 353 may detect electrostatic properties using AC signals of different frequencies for each of the plurality of electrode pairs 351A to 351E. As a result, the respective detection signals can be superimposed and the electrostatic characteristics can be detected at once without crosstalk. Alternatively, as shown in FIG. 4B, a selector 354 is further provided for selecting any two of the plurality of electrodes 351a to 351e and rearranging them into one of the plurality of electrode pairs 351A to 351E. The electrode pairs 351A to 351E may be connected to the detector 353 in order. The detection unit 353 sequentially detects the electrostatic characteristics between the two electrodes 351a to 351e of the electrode pairs 351A to 351E connected by the selector 354, and transmits the detection results to the control device 150. FIG.

Note that the control device 150 determines the state of the contact area based on the detection result of the electrostatic characteristics between the two electrodes 351a to 351e of each of the electrode pairs 351A to 351E, and the determination result of the determination unit 150a. and a controller 150b for controlling the tilt between the substrates 211 and 213 based on the control unit 150b. When the determination unit 150a determines that the expansion of the contact area 215 is not uniform, the control unit 150b controls the lower stage 332 to tilt the substrate 213 with respect to the substrate 211 in the direction in which the expansion of the contact area 215 is fast or slow. By increasing or decreasing , the contact area 215 can be uniformly enlarged.

4A and 4B show an example of arrangement of the plurality of electrodes 351 of the bonding detection device 350 in plan view. As an example, the substrates 211 and 213 are assumed to form a contact region 215 by contacting a part of their centers. The up-down direction of the drawing is defined as the vertical direction, and the left-right direction of the drawing is defined as the horizontal direction.

Two electrodes 351a to 351d respectively included in the four electrode pairs 351A to 351D are arranged to face each other across the edges of the substrates 211 and 213 supported by the upper stage 322 and the lower stage 332, respectively. The pair of electrodes 351a are arranged vertically across the left edges of the substrates 211 and 213, which are separated from the contact area 215 in the left direction in plan view. The pair of electrodes 351b are arranged vertically across the right edges of the substrates 211 and 213 that are separated from the contact area 215 to the right in plan view. The pair of electrodes 351c are arranged laterally across the upper edges of the substrates 211 and 213, which are separated upward from the contact area 215 in plan view. The pair of electrodes 351d are arranged laterally across the lower edges of the substrates 211 and 213 that are spaced downward from the contact area 215 in plan view. By detecting the electrostatic properties between the two electrodes 351a-351d of each of the electrode pairs 351A-351D, the end of the contact area expansion can be detected at each edge.

The two electrodes 351e included in the electrode pair 351E are arranged laterally of the substrates 211 and 213 respectively supported by the upper stage 322 and the lower stage 332 on a straight line passing through the center of the contact area 215 in the plane direction, that is, in plan view. They are arranged opposite each other on the upper right and lower left, respectively. By detecting the electrostatic properties of the pair of electrodes 351e, it is possible to detect the expansion process of the contact area during bonding of the substrates.

Note that the electrode 351e has a larger electrode surface than the electrodes 351a to 351d. As shown in FIGS. 4A and 4B, when the electrode 351e is arranged outside the electrodes 351a to 351d so as not to interfere with the electrodes 351a to 351d in plan view, the signal intensity obtained from the electrode pair 351E is It can be maintained so as not to become smaller than the signal strength obtained from the electrode pairs 351A to 351D.

5A-6B further show another example of the arrangement of the plurality of electrodes 351. FIG.

In the example shown in FIG. 5A, the plurality of electrodes 351 includes a plurality of pairs of two electrodes, an electrode pair 351A having two electrodes 351a, an electrode pair 351B having two electrodes 351b, and two electrodes 351c. It includes an electrode pair 351C and an electrode pair 351D with two electrodes 351d. Two electrodes 351a to 351d included in each of the four electrode pairs 351A to 351D face each other laterally of the substrates 211 and 213 with an angular interval of 45 degrees sandwiching the contact region 215 in the plane direction. are arranged as follows. By detecting the electrostatic characteristics of each of the electrode pairs 351A to 351D, it is possible to detect the expansion process of the contact area 215 in each direction during bonding of the substrates. The number of electrode pairs is not limited to four, and may be two or more.

The example shown in FIG. 5B is a modification of the example shown in FIG. 5A, in which guides 355 are provided to rotatably support the two electrodes 351a included in the electrode pair 351A in the circumferential direction of the substrates 211 and 213. there is The two electrodes 351 a are arranged on the sides of the substrates 211 and 213 so as to face each other with the contact area 215 interposed therebetween in the planar direction, and their positions in the circumferential direction can be arbitrarily changed along the guide 355 . By detecting the electrostatic properties between the two electrodes 351a while changing the circumferential positions of the electrodes 351a, it is possible to detect the expansion process of the contact area 215 in an arbitrary direction during bonding of the substrates. Note that the number of electrode pairs is not limited to one and may be plural.

In the example shown in FIG. 6A, the plurality of electrodes 351 includes a plurality of pairs of two electrodes, an electrode pair 351A having two electrodes 351a, an electrode pair 351B having two electrodes 351b, and two electrodes 351c. An electrode pair 351C, an electrode pair 351D having two electrodes 351d, an electrode pair 351E having two electrodes 351e, an electrode pair 351F having two electrodes 351f, an electrode pair 351G having two electrodes 351g, and two electrodes 351h. and electrode pair 351H. Two electrodes 351a to 351h included in each of the eight electrode pairs 351A to 351H are arranged on the sides of the substrates 211 and 213 so as to face each other with the substrates 211 and 213 interposed therebetween.

The three electrode pairs 351A to 351C vertically sandwich the left edges, the central contact area 215, and the right edge of the substrates 211 and 213 with the two electrodes 351a to 351c included in each pair in plan view. and are laterally spaced apart from each other. Here, one of the electrodes 351a to 351c of each pair is arranged on the substrates 211 and 213 in a laterally straight line, and the other electrodes 351a to 351c are arranged laterally under the substrates 211 and 213. arranged in a straight line.

The three electrode pairs 351D to 351F have two electrodes 351d to 351f included in each pair laterally sandwiching the upper edges, the central contact area 215, and the lower edge of the substrates 211 and 213 in plan view. and are spaced apart from each other in the longitudinal direction. Here, one of the electrodes 351d to 351f of each pair is arranged on the left side of the substrates 211 and 213 in a straight line in the vertical direction, and the other electrodes 351d to 351f are arranged on the right side of the substrates 211 and 213 in the vertical direction. arranged in a straight line.

The two electrodes 351g included in the electrode pair 351G are arranged on the upper right and lower left sides of the substrates 211 and 213 with the contact area 215 interposed therebetween in plan view.

The two electrodes 351h included in the electrode pair 351H are arranged on the upper left and lower right sides of the substrates 211 and 213 with the contact area 215 interposed therebetween in plan view.

By detecting the electrostatic characteristics of each of the electrode pairs 351A to 351H, the expansion process of the contact area 215 in the vertical direction is detected from the electrostatic characteristics of the electrode pair 351B, and the end of the process is detected by the electrostatic characteristics of the electrode pairs 351D and 351F. The lateral expansion process of the contact area 215 can be detected from the electrostatic properties of the electrode pair 351E, and the end can be detected from the electrostatic properties of the electrode pairs 351A and 351C. , 351H, the expansion process of the contact area 215 in each oblique direction can be detected.

The example shown in FIG. 6B is a modification of the example shown in FIG. 6A, in which a pair of guides 356 and two electrodes included in an electrode pair 351D support laterally movably two electrodes 351a included in an electrode pair 351A. A pair of guides 357 are provided for vertically movably supporting the electrodes 351d.

One of the two electrodes 351a is arranged on one side of the substrates 211 and 213 in the vertical direction and the other is arranged on the other side, facing each other with the substrates 211 and 213 interposed therebetween. By moving the two electrodes 351a along the guide 356, the lateral position of the electrode pair 351A can be arbitrarily changed. By detecting the electrostatic properties between the two electrodes 351a included in the electrode pair 351A while changing the position of the electrode pair 351A in the lateral direction, the contact area 215 at each position in the lateral direction when the substrates are bonded. The expansion process or its end can be detected. Note that the number of electrode pairs 351A is not limited to one and may be plural.

One of the two electrodes 351d is arranged on one lateral side of the substrates 211 and 213 and the other is arranged on the other side, facing each other with the substrates 211 and 213 interposed therebetween. By moving the two electrodes 351d along the guide 357, the vertical position of the electrode pair 351D can be arbitrarily changed. By detecting the electrostatic properties between the two electrodes 351d included in the electrode pair 351D while changing the position of the electrode pair 351D in the vertical direction, the contact area 215 at each position in the vertical direction when the substrates are bonded. The expansion process or its end can be detected. Note that the number of electrode pairs 351D is not limited to one, and may be plural.

The principle of bonding the substrates 211 and 213 will be described.

FIG. 7A schematically shows a cross-sectional configuration of the holder 221 holding the substrate 211 carried into the bonding apparatus 300. As shown in FIG. The holder 221 attracts and holds the substrate 211 on the holding surface 222 using an electrostatic chuck, a vacuum chuck, or the like. Here, the holding surface 222 has a curved shape with a high central side and a low peripheral edge. As a result, the substrate 211 sucked and held by the holding surface 222 is in close contact with the holding surface 222 and is curved in a convex shape with the central side protruding, and the shape is maintained. The shape of the holding surface 222 of the holder 221 may be spherical, parabolic, cylindrical, or the like. In the bonding apparatus 300 , a convexly curved substrate 211 is supported by an upper stage 322 via a holder 221 .

FIG. 7B schematically shows a cross-sectional configuration of holder 223 holding substrate 213 . The holder 223 attracts and holds the substrate 213 on the holding surface 224 using an electrostatic chuck, a vacuum chuck, or the like. Here, the holding surface 224 has a flat shape. As a result, the substrate 213 sucked and held by the holding surface 224 is flattened in close contact with the holding surface 224, and its shape is maintained. In the bonding apparatus 300 , the substrate 213 is supported by the lower stage 332 via the holder 223 .

FIG. 8A shows a state in which two substrates 211 and 213 are aligned in the substrate bonding process. The substrate 211 is held by the holder 221 and curved in a convex shape at the center, and is supported downward by the upper stage 322 via the holder 221. The substrate 213 is positioned directly below the substrate 211 by supporting the stage 332 upward and driving the lower stage 332 in the planar direction. At least one surface of substrates 211 and 213 is activated by plasma exposure using activation devices 326 and 336 . At this time, the plurality of electrodes 351 of the bonding detection device 350 are arranged laterally of the substrates 211 and 213 by the electrode driving device 352 .

FIG. 8B shows a state in which a contact region 215 is formed between the two substrates 211 and 213 in the substrate bonding process. Since the center of the substrate 211 supported by the upper stage 322 via the holder 221 is curved in a convex shape, the lower stage 332 is brought close to the upper stage 322 by the elevation driving unit 338, and the substrate 211 is By pressing the substrate 213 that is flatly supported against the lower stage 332 via the holder 223, the centers of the substrates 211 and 213 come into strong contact. As a result, a contact region 215 is formed at the center of the substrates 211 and 213 as a starting point for bonding. At this time, the peripheral edge of the substrate 211 is separated from the substrate 213 .

FIG. 8C shows a state in which a bonding wave is in progress in the substrate bonding process. The substrate 211 is released from the upper stage 322 by releasing the holder 221 held by the upper stage 322 . At this time, since at least one surface of the substrates 211 and 213 is activated, adjacent regions of the respective substrate surfaces are autonomously adsorbed to each other due to the intermolecular force between the substrates 211 and 213. As a result, the contact area 215 expands to the surroundings. As a result, the bonding wave 232, which is the boundary between the contact area with which the substrates 211 and 213 are in contact and the non-contact area with which the substrates 211 and 213 are not yet in contact, moves from the center of the substrates 211 and 213 toward the periphery. expands and bonding of the substrates 211 and 213 progresses.

FIG. 8D shows a state in which bonding of the substrates in the substrate bonding process is completed. Once the bonding wave 232 has moved to the perimeter of the substrates 211 and 213 and the contact area 215 has expanded over the substrates 211 and 213 , the substrates 211 and 213 are bonded together to form a bonded substrate 230 .

In such a bonding principle of the substrates 211, 213, the contact area 215 of the substrates 211, 213 expands from the center of the substrates 211, 213 toward the periphery. As a result, the atmosphere sandwiched between the substrates 211 and 213 before bonding, for example, the atmosphere, is pushed outward in the process of expanding the contact area between the substrates 211 and 213, and the bonded substrates 211 and 213 Air bubbles are prevented from remaining in between.

In this embodiment, the substrate 211 deformed into a convex shape and the flat substrate 213 are bonded together. Similarly, when the substrates 211 and 213 are deformed into a convex shape and a concave shape with different curvatures, and when the substrates 211 and 213 are deformed into a cylindrical shape whose central axes are not parallel, the substrates 211 and 213 are in contact with each other. By forming a region 215 and enlarging it, bonding can be performed.

9A and 9B show the electrode shape of the electrode 351 and the principle of displacement detection of the substrate 211. FIG. As described with reference to FIGS. 8A to 8D, in the substrate bonding process, the bonding wave 232 moves from the center of the substrates 211 and 213 toward the periphery, and the contact area 215 between the substrates 211 and 213 expands. Bonding of the substrates 211 and 213 proceeds. Here, it is assumed that the electrode surface of the electrode 351 is circular, and the electrode 351 is arranged such that the end surface of the substrate 211 faces the upper half of the circular electrode surface. As a result, the end face of the substrate ₂₁₁ moves from the position Z1 in the Z _- axis direction to _a lower position Z2, and accordingly the area of the portion of the electrode facing the end face of the substrate ₂₁₁ increases from S1 to S2. Then, the capacitance between the electrode 351 and another opposing electrode 351 increases from C ₁ =εS ₁ /D to C ₂ =εS ₂ /D. Here, ε is the dielectric constant of the substrate 211 , D is the separation distance between the electrodes, and it is assumed that the capacitance between the electrodes is predominantly determined by the substrate 211 . Therefore, the position of the substrate 211 in the Z-axis direction is detected by detecting the change in capacitance between the two electrodes 351, thereby expanding the contact area 215 formed between the substrates 211 and 213. can be detected.

FIG. 9C shows an example of the result of displacement detection of the substrate 211 during the process of bonding the substrates 211 and 213 together. In this example, the time change of the detection result of the capacitance of the pair of electrodes 351e in FIG. 4A is shown. This time change reflects the motion of the substrate 211 in the electric field between the two electrodes 351e. The bonding of the substrates 211 and 213 is started at time 10 seconds by releasing the holding of the substrate 211 by the upper stage 322 . Accompanying this, the capacitance increases from the value C1, remains approximately constant during the time period T of ₁₂ to 18 seconds during which bonding is progressing, and then increases again and saturates at _C2 . As a result, bonding is completed at time 24 seconds. The expansion of the bonding wave 232, that is, the expansion process of the contact area 215 can be read from this change in capacitance over time.

FIG. 9D shows another example of the result of displacement detection of the substrate 211 during the substrate bonding process of the substrates 211 and 213. As shown in FIG. In this example, the time change of the detection result of the capacitance of the pair of electrodes 351a in FIG. 4A is shown. Bonding of the substrates 211 and 213 is started at time 16 seconds by releasing the holding of the substrate 211 by the upper stage 322 . Accompanying this, the capacitance increases from the value C1, remains _{approximately} constant during the period T of 18 to 26 seconds during which bonding is progressing, and then increases again and saturates at _C2 . As a result, it can be read that the expansion of the bonding wave 232, that is, the expansion of the contact area 215 reaches the left edges of the substrates 211 and 213 at time 35 seconds, and the bonding is completed.

10A and 10B show another principle of electrode shape of the electrode 351 and displacement detection of the substrate 211. FIG. In this example, the electrode surface of the electrode 351 is circular, and the electrode 351 is arranged such that the end surface of the substrate 211 faces the lower half of the circular electrode surface. As a result, the end face of the substrate ₂₁₁ moves from the position Z1 in the Z _- axis direction to _a lower position Z2, and accordingly the area of the portion of the electrode facing the end face of the substrate ₂₁₁ decreases from S1 to S2. Then, the capacitance between the electrode 351 and the other opposing electrode 351 decreases from C ₁ =εS ₁ /D to C ₂ =εS ₂ /D. Here, ε is the dielectric constant of the substrate 211 , D is the separation distance between the electrodes, and it is assumed that the capacitance between the electrodes is predominantly determined by the substrate 211 . With such an electrode arrangement, it is also possible to detect the position of the substrate 211 in the Z-axis direction by detecting a change in the capacitance between the two electrodes 351 , thereby forming a capacitance between the substrates 211 and 213 . It can be seen that the expansion process of the contact area 215 can be detected.

FIG. 10C shows an example of the result of displacement detection of the substrate 211 during the process of bonding the substrates 211 and 213 together. In this example, the time change of the detection result of the capacitance of the pair of electrodes 351e in FIG. 4A is shown. The bonding of the substrates 211 and 213 is started at time 12 seconds by releasing the holding of the substrate 211 by the upper stage 322 . Accompanying this, the capacitance decreases from the value C1, remains _{approximately} constant during the period T from time 17 to 23 seconds during which bonding is progressing, and then decreases again and saturates at _C2 . As a result, bonding ends at time 37 seconds. The expansion of the bonding wave 232, that is, the expansion process of the contact area 215 can be read from this change in capacitance over time.

Note that in any of the examples of FIGS. 9C, 9D, and 10C, there is a period during which the change in capacitance is extremely small despite the progress of bonding. Therefore, the judgment unit 150a judges that bonding has started from the start of the change in capacitance, and sets a predetermined period, for example, about 10 seconds, including a period in which the change in capacitance becomes minimal, as a mask period. After the end of the period, it is judged that the bonding is completed from the saturation of the capacitance.

9C and 10C, by detecting the change in the capacitance between the pair of electrodes 351e, the bonding wave 232 spreads in the direction in which the electrodes 351e are arranged, that is, the contact area 215 expands. progress can be known. Therefore, the bonding detection device 350 (which is also an example of progress unevenness detection means for expanding the contact area 215) detects the electrode pairs 351A to 351D arranged as shown in FIG. By accumulating changes over time in the detection results of the capacitances of the electrode pairs 351A to 351D and grasping the relationship with the progress of expansion of the contact area 215, the electrode pair 351A during the step of bonding the substrates 211 and 213 together. From the detection result of the capacitance of ˜351D, it is possible to detect the progress speed of the expansion of the contact area 215 in the arrangement direction of each electrode pair, especially the progress unevenness of the expansion.

11A and 11B show another electrode shape of the electrode 351 and the principle of displacement detection of the substrate 211. FIG. In this example, the electrode surface of the electrode 351 has a rectangular shape and is arranged to be inclined with respect to the Z-axis direction. As a result, the end face of the substrate ₂₁₁ moves from the position Z1 in the Z _- axis direction to a lower position Z2, and along with this, the area of the portion of the electrode facing the end face of the substrate 211 remains S. The separation distance between the electrode and the end face of the substrate 211 decreases from D1 to D2, and the capacitance between the electrode 351 and _another opposing electrode 351 changes from C1 _{= ε0S / D1} to C ₂ increases to ε ₀ S/D ₂ . Here, ε ₀ is the dielectric constant of the atmosphere, and it is assumed that the change in the capacitance between the electrodes is predominantly determined by the change in the distance in the atmosphere. With such an electrode arrangement, it is also possible to detect the position of the substrate 211 in the Z-axis direction by detecting a change in the capacitance between the two electrodes 351 , thereby forming a capacitance between the substrates 211 and 213 . It can be seen that the expansion process of the contact area 215 can be detected.

It should be noted that not only the rectangular electrodes shown in FIG. 11A, but also the circular electrodes shown in FIG. good. Thereby, the detection sensitivity of the electrostatic properties between the two electrodes 351 can be improved.

FIG. 12 shows a flow of substrate bonding procedures by the bonding apparatus 300 . In the substrate bonding system 100, each component operates under the control of the controller 150b of the controller 150. FIG. Prior to bonding the substrates, a substrate cassette 120 containing substrates 210 to be bonded together and a substrate cassette 130 containing the bonded substrates 230 are fixed to the housing 110 . It is assumed that the electrodes 351 are lifted by the electrode driving device 352 and retracted to the side of the upper stage 322 .

In step S<b>101 , the substrate 210 is carried into the bonding apparatus 300 . As shown in FIG. 13A, the holder 221 is taken out from the holder stocker 400 and transported to the pre-aligner 500 by the transport device 140, the substrate 211 is taken out from the substrate cassette 120 and transported to the pre-aligner 500, and the substrate 211 is held by the holder 221. . The holder 221 holding the substrate 211 is carried into the bonding apparatus 300 and fixed to the upper stage 322 with the substrate 211 facing downward. Further, the carrier device 140 takes out the holder 223 from the holder stocker 400 and carries it to the pre-aligner 500 , takes out the substrate 213 from the substrate cassette 120 and carries it to the pre-aligner 500 , and makes the holder 223 hold the substrate 213 . The holder 223 holding the substrate 213 is carried into the bonding apparatus 300 and fixed to the lower stage 332 with the substrate 213 facing upward.

Next, the position of the lower stage 332, ie the relative positions of the microscopes 324, 334 are calibrated. The detailed procedure is as described above.

In step S102, microscopes 324 and 334 are used to detect alignment marks of substrates 211 and 213, respectively. As shown in FIG. 13B, under the control of the control device 150, the interferometer 341 measures the position of the lower stage 332, and based on the measurement results, the X-direction driving section 331 and the Y-direction driving section 333 move the lower stage 332 horizontally. By driving in the directions, the alignment marks of the substrate 213 are sequentially positioned within the field of view of the microscope 324 and detected by the microscope 324 . Under the control of the controller 150, the interferometer 341 measures the position of the lower stage 332, and the X-direction driving section 331 and the Y-direction driving section 333 drive the lower stage 332 in the horizontal direction based on the measurement result. Thus, the alignment marks of the substrate 211 are sequentially positioned within the field of view of the microscope 334 and detected by the microscope 334 . From the measurement result of interferometer 341 and the detection result of microscopes 324 and 334, the mutual positional relationship of the alignment marks of substrates 211 and 213, that is, the positional relationship of substrates 211 and 213 is determined.

In step S103, the activation devices 326 and 336 activate the surfaces of the substrates 211 and 213, respectively. As shown in FIG. 13C, the activation device 326 exposes the surface of the substrate 213 to plasma, the activation device 336 exposes the substrate 211 to plasma, and the X-direction driver 331 and Y-direction driver 333 expose the surface of the substrate 211 to plasma. By driving the stage 332 in the direction of the arrow S, the entire surfaces of the substrates 211 and 213 are cleaned and activated. As a result, when the substrates 211 and 213 are brought into contact with each other, the substrates 211 and 213 are bonded to each other and integrated.

The substrates 211 and 213 can also be activated by mechanical treatment such as polishing or chemical treatment such as cleaning. The substrates 211 and 213 can also be activated by sputter etching using an inert gas, ion beams, fast atom beams, or the like. When using an ion beam or a fast atom beam, the bonding apparatus 300 can be produced under reduced pressure. Also, the substrates 211 and 213 can be activated by ultraviolet irradiation, ozone asher, or the like. It may also be activated by chemically cleaning the surfaces of the substrates 211, 213, for example using a liquid or gaseous etchant. Moreover, you may use together the activation method of multiple types.

Also, the activation devices 326 and 336 may be provided outside the bonding apparatus 300 instead of inside. In this case, the surfaces of the substrates 211 and 213 may be activated before the substrates 211 and 213 are loaded into the bonding apparatus 300 and the activated substrates 211 and 213 may be loaded into the bonding apparatus 300 .

In step S104, the substrate is corrected by adjusting the temperature of at least one of the substrates 211 and 213 to compensate for the magnification difference with respect to the design specifications. Deformation such as warping of the substrates 211 and 213 may be corrected by a method other than temperature control, for example, a correction method of deforming at least one of the substrates 211 and 213 using an actuator provided on the upper stage 322 or the lower stage 332. good. As a result, the substrates 211 and 213 can be aligned with high accuracy even when the individual substrates 211 and 213 have inherent distortion.

The order of step S103 for activating the substrates 211 and 213 and step S104 for adjusting the temperature of the substrates 211 and 213 may be exchanged. Moreover, step S104 of adjusting and correcting the temperature of at least one of the substrates 211 and 213 may be performed before step S102 of detecting the alignment marks of the substrates 211 and 213, respectively.

In step S105, the substrates 211 and 213 to be bonded are aligned with each other. As shown in FIG. 13D, the X-direction driving unit 331 and the Y-direction driving unit 331 and the Y-direction driving unit are operated so that the positional deviation between the alignment marks is statistically minimized or equal to or less than the threshold based on the previously determined positional relationship between the substrates 211 and 213 . The substrate 211 is horizontally positioned by driving the lower stage 332 with 333 . Here, enhanced global alignment may be employed as a statistical alignment method.

In step S<b>106 , the plurality of electrodes 351 of the bonding detection device 350 are arranged laterally of the substrates 211 and 213 . As shown in FIG. 13E, the lower stage 332 is driven upward by raising the elevation drive section 338 . Thereby, the substrate 213 supported by the lower stage 332 approaches the substrate 211 supported by the upper stage 322 . In this state, as described with reference to FIG. 8A, the plurality of electrodes 351 of the bonding detection device 350 are lowered by the electrode driving device 352, and the substrates 211 and 213 are sandwiched in the plane direction. to be placed.

In step S107, parts of the substrates 211 and 213 are brought into contact with each other to form a bonding starting point. As shown in FIG. 13F, the lower stage 332 that supports the substrate 213 is driven upward by raising the elevation drive unit 338 . As a result, as described with reference to FIG. 8B, the center of the substrate 213 is pressed against the substrate 211, the atmosphere and the like sandwiched between the substrates 211 and 213 are pushed out, and a part of each of the substrates 211 and 213 is pushed out. A contact region 215 is formed in contact with each other to form a bonding starting point. The origin may be a region having an area.

This contact causes the contact areas of the activated substrates 211, 213 to join together through chemical bonds, such as hydrogen bonds. After the substrates 211 and 213 are brought into partial contact, the substrates 211 and 213 are kept in contact with each other. At this time, by pressing the substrates 211 and 213 against each other, the contact area may be widened by enlarging the contact area. After a predetermined period of time has elapsed while the contact state is maintained, a bonding force is secured between the substrates 211 and 213 that is large enough to prevent displacement between the substrates 211 and 213 during the bonding process of the substrates 211 and 213 . be. As a result, a starting point for bonding is formed at a portion of the substrates 211 and 213 that are in contact with each other.

In step S108, a contact area is formed between the substrates 211 and 213, and it is checked whether or not the bonding force of the predetermined magnitude is secured between the two substrates 210 as described above. If it is detected at this stage that the substrates 211 and 213 have been bonded together, it is checked whether or not a starting point of bonding has been formed as a trigger for starting the bonding of the substrates 211 and 213 . Therefore, in step S107, it is checked whether or not a region where a part of the substrates 211 and 213 are pressed or a region serving as a bonding starting point is formed at a position close to the region.

When it is determined that the bonding starting point is formed on the substrate 210, that is, when it is determined that the bonding force of the predetermined magnitude is ensured between the contact portions of the two substrates 211 and 213, the following is performed. to step S109. If it is not confirmed that the starting point is formed on the substrates 211 and 213, while continuing to hold both the substrates 211 and 213, a portion of the substrates 211 and 213 continues to be pressed to form the starting point for bonding.

In step S109, the holding of the substrate 211 by the holder 221 is released. As a result, the substrate 211 is released, and as described with reference to FIG. 8C, the intermolecular force between the substrates 211 and 213 causes the regions adjacent to the contact regions to adhere autonomously, and the contact regions are successively moved in the plane direction. An expanding bonding wave is generated, which causes substrate 211 to distort while bonding substrates 211 and 213 together.

Bonding of the substrates 211 and 213 means stacking the main surfaces of the substrates 211 and 213 parallel to each other and fixing their relative positions by hydrogen bonding, van der Waals bonding, covalent bonding, or the like. On the other hand, stacking the substrates 211 and 213 means that the main surfaces of the substrates 211 and 213 are in contact with each other, but does not necessarily mean that the relative positions of the substrates 211 and 213 are fixed. In addition, "laminate" may be used synonymously with "stack". In some cases, the substrates 211 and 213 start to be bonded at the place where they are stacked. The joint may be completed at a different location than where it was mated. In some cases, the substrates 211 and 213 are joined by heating, pressing, or the like at a location other than the aligned location.

In step S110, the bonding detection device 350 is used to determine the state of the contact area. For example, the electrostatic characteristics of each of the plurality of electrode pairs 351A to 351E arranged as shown in FIG. 4A are detected, and the determination unit 150a detects the electrostatic characteristics as described with reference to FIGS. 9A to 10C. The state of the contact area can be determined from the time change of .

In step S111, it is checked whether or not the contact area of the substrates 211 and 213 spreads from the bonding starting point formed on the substrates 211 and 213 . If it can be confirmed that the contact area between the substrates 211 and 213 has expanded, the judgment unit 150a judges that the bonding of the substrates 211 and 213 is progressing, and advances to the next step S112 to confirm. If not, the determination unit 150a determines that bonding of the substrates 211 and 213 is hindered for some reason, and proceeds to step S114.

Here, the tilt between the substrates 211 and 213 may be controlled based on the detection results of the electrostatic properties of the plurality of electrode pairs 351A-351E. For example, from the detection result of the electrostatic characteristics of each of the plurality of electrode pairs 351A to 351E arranged as shown in FIG. If it is advanced or delayed with respect to the change, the determination unit 150a determines that the expansion of the contact area progresses unevenly, and the expansion of the contact area in that direction progresses with respect to the expansion in other directions. Or judge that it is late. The controller 150b controls the lower stage 332 to increase or decrease the leftward tilt of the substrate 213 with respect to the substrate 211 based on the determination by the determination unit 150a. Thereby, the contact area 215 can be uniformly enlarged.

Note that when at least one of the upper stage 322 and the lower stage 322 is provided with an actuator that mechanically deforms the substrates 211 and 213, the control unit 150b controls the drive amount of the actuator based on the determination by the determination unit 150a. , the amount of deformation of the substrates 211 and 213 may be adjusted. If at least one of the upper stage 322 and the lower stage 322 is provided with a heater or the like for adjusting the temperature of the substrates 211 and 213, the control section 150b controls the amount of temperature adjustment by the heater based on the judgment by the judgment section 150a. , the amount of deformation of the substrates 211 and 213 may be adjusted. In addition, the upper stage 322 is provided with a vent hole penetrating in the thickness direction, and a vent hole communicating with the holder 221 holding the substrate 211 is also provided. fluid to the substrate 211 through the ventilation holes of the upper stage 322 and the holder 322, the controller 150b determines whether the expansion of the contact area is slow or fast, based on the determination by the determination unit 150a. The flow rate and fluid pressure from the vent corresponding to the region may be adjusted. Further, the holding surface of the holder 221 may be divided into a plurality of areas along at least one of the radial direction and the circumferential direction, and the adsorption force of vacuum adsorption or electrostatic adsorption may be controlled for each area. In this case, the release timing of the substrate 211 from the holder 221 may be controlled for each area according to the speed of enlargement of the enlarged area. In this way, when the holding of the substrate 211 by the holder 221 can be released non-uniformly, the controller 150b, based on the determination by the determination unit 150a, releases the adsorption by the area corresponding to the region where the contact region is slow to expand. Alternatively, the control may be performed at a timing earlier than the release of the adsorption by the area corresponding to the region that expands rapidly. In addition, the holding surface of the holder 223 is divided into a plurality of areas along at least one of the radial direction and the circumferential direction, the adsorption force of vacuum adsorption or electrostatic adsorption can be controlled for each area, and the contact area can be expanded. Depending on the speed, the progress of expansion of the contact area may be controlled for each area. In this way, when the holding of the substrate 213 by the holder 223 can be released non-uniformly, the control unit 150b, based on the determination by the determination unit 150a, reduces the adsorption force of the area corresponding to the area where the contact area is slow to expand. Control may be performed to weaken the attraction force by the area corresponding to the region where the expansion is fast. Alternatively, the lower stage 332 that supports the substrate 213 may be driven upward or downward by the elevation driving section 338 to adjust the gap between the substrates 211 and 213 .

Note that when the speed of expanding the contact area is faster than the predetermined speed, the control unit 150b controls the speed of expanding the contact area of the substrates 211 and 213 even during the bonding process of the substrates 211 and 213, Correction controls may be modified. For example, it is possible to detect that the magnification that occurs during the bonding process differs from the plan due to individual differences in substrates, changes in the environment, etc., and to correct this. The predetermined speed can be set based on the detection result of the expansion speed of the contact area obtained in past bonding of the substrates. The relationship between the magnification (non-linearity) occurring during the bonding process of the substrates and the expansion speed of the contact area is grasped in advance based on the data of substrates of the same kind. The enlargement speed is set by setting the magnification (non-linearity) that will occur during the bonding process of the substrates to be the same as that of the previously bonded substrates. Note that, if a change in magnification or a change in the expansion speed of the contact area due to environmental factors or the like is predicted, these are also predicted and the scheduled speed is set.

Such control of the lower stage 332 by the control unit 150b may be performed in real time, or may be performed when bonding the next substrate. Alternatively, it may be performed for each lot of substrates, each time the recipe of the bonding process is changed, or the like.

In step S111, the determination unit 150a further detects the speed or degree of expansion of the contact area 215 between the substrates 211 and 213, thereby predicting the time when bonding of the substrates 211 and 213 will be completed. may The speed or degree of expansion of the contact area 215 can be calculated, for example, from profiles of changes over time in the electrostatic properties between the two electrodes 351 shown in FIGS. 9C, 9D, and 10C.

Further, from the detection results of the electrostatic characteristics of each of the plurality of electrode pairs 351A to 351D arranged as shown in FIG. The shape of region 215 may be detected. The shape of contact area 215 may vary with its enlargement. Therefore, when the contact area 215 maintains the circular shape, the determination unit 150a determines that the bonding of the substrates 211 and 213 is progressing normally, proceeds to the next step S112, and does not maintain the circular shape. If the deviation from the circular shape becomes large, the determination unit 150a determines that the bonding of the substrates 211 and 213 is not progressing normally, and proceeds to step S114.

In step S112, it is checked whether bonding of the substrates 211 and 213 is completed. The determining unit 150a can confirm completion of bonding when the electrostatic characteristics of the plurality of electrode pairs 351A to 351E stop changing with time and saturate at a constant value. Here, as described with reference to FIGS. 9C, 9D, and 10C, the detection result of the capacitance between the two electrodes 351a to 351e included in each of the electrode _pairs 351A to 351E increases from C1. , saturates to _C2 after a certain period of time when the change is minimal. Therefore, the determination unit 150a determines that the capacitance detection result starts to change, and after a mask period longer than a certain period elapses, the capacitance detection result becomes |C ₂ | or a certain ratio of |C ₂ −C ₁ | and the difference from _C2 becomes equal to or less than the threshold value, the completion of bonding may be confirmed. This makes it possible to reliably confirm the completion of bonding even when the time required for bonding differs between the substrates 211 and 213 . If completion of bonding of the substrates 211 and 213 cannot be confirmed even after a predetermined threshold time elapses, the determination unit 150a may determine that completion of bonding of the substrates could not be confirmed. If the completion of bonding of the substrates is confirmed, the process proceeds to the next step S113, and if not confirmed, the process proceeds to step S114.

In step S113, the bonded substrate 230 formed by bonding the substrates 211 and 213 together is unloaded. As shown in FIG. 13G , the electrodes 351 are lifted by the electrode driving device 352 and retreated to the side of the upper stage 322 , the temperature control and the like for the substrates 211 and 213 are completed, and the lower stage 332 is moved by the elevation driving unit 338 . , and the transport device 140 carries out the bonded substrate stack 230 from the bonding device 300 . The bonded substrate 230 is separated from the holders 221 and 223 and accommodated in the substrate cassette 130 .

In step S114, actions such as stopping the operation of the bonding apparatus 300, transmitting an alarm to the outside, and unloading the substrates 211 and 213 being bonded from the bonding apparatus 300 are executed.

This completes the substrate bonding procedure of the substrates 211 and 213 .

According to the substrate bonding apparatus 300 according to this embodiment, the contact area 215 is formed between the substrates 211 and 213 so that parts of the substrates 211 and 213 are in contact with each other, and the contact area 215 is expanded in the planar direction along the bonding surface. At least a pair of electrodes 351 arranged with the substrates 211 and 213 interposed in the plane direction, and between two electrodes included in the at least pair of electrodes 351 and a detection unit 353 for detecting the electrostatic characteristics of the. A contact area 215 is formed by bringing a part of each of the substrates 211 and 213 into contact with each other. By detecting the electrostatic properties of at least one pair of electrodes 351 arranged in , the state of the contact area 215, that is, the bonding process of the substrates 211 and 213 can be detected.

According to the substrate bonding method according to the present embodiment, the contact region 215 is formed between the substrates 211 and 213 in which portions of the substrates 211 and 213 are in contact with each other, and the contact region 215 is expanded in the planar direction along the bonding surface. In this method, the substrates 211 and 213 are directly attached to each other. a step of forming contact region 215 , expanding contact region 215 in a planar direction along the bonding surface, and detecting electrostatic characteristics between two electrodes included in at least a pair of electrodes 351 . A contact region 215 is formed by bringing a part of each of the substrates 211 and 213 into contact with each other. By detecting the electrostatic properties of the pair of electrodes 351, the state of the contact area 215, that is, the bonding process of the substrates 211 and 213 can be detected.

Note that the bonding apparatus 300 according to this embodiment employs a configuration in which the substrates 211 and 213 are held on the upper stage 322 and the lower stage 332 via the holders 221 and 223. A configuration in which the substrates 211 and 213 are directly held on the upper stage 322 and the lower stage 332 without using the substrates may be employed. In such a case, the holding surface of the upper stage 322 may have a curved shape with a high central side and a low peripheral edge. The substrate 211 is held by suction on the holding surface of the upper stage 322, is in close contact with the holding surface, and is curved in a convex shape with the central side protruding, and the shape is maintained.

In the substrate bonding apparatus 300 according to this embodiment, as shown in FIGS. 9A and 9B or FIGS. Although electrode 351 is positioned, electrode 351 may be positioned to detect only the end of expansion of contact area 215 . 14A and 14B show a modification of the electrode arrangement and the principle of substrate displacement detection.

In the modification shown in FIG. 14A, at least one of the pair of electrodes 351 is arranged on the back side of the substrate 211 after being bonded to the substrate 213 in the Z-axis direction. According to this, while the contact area between the substrates 211 and 213 is expanding, the end surface of the substrate 211 faces the electrode 351, so that the capacitance of the substrate 211 can be detected from the electrode 351. When the expansion of the contact area of the substrates 211 and 213 progresses to the edge of the substrates 211 and 213 and ends, the capacitance of the substrate 211 is not detected by the electrode 351 because the edge surface of the substrate 211 does not face the electrode 351, and the atmosphere of capacitance is detected. Therefore, the determining unit 150a can determine that the expansion of the contact area 215 is completed, that is, the bonding of the substrates is completed when the electrostatic capacitance of the atmosphere is detected from the result of detecting the electrostatic characteristics between the electrodes 351. .

In the modification shown in FIG. 14B, at least one of the pair of electrodes 351 is arranged at a position facing the end surface of the substrate 211 after being bonded to the substrate 213 in the Z-axis direction. According to this, while the contact area between the substrates 211 and 213 is expanding, the end face of the substrate 211 does not face the electrode 351, so the electrode 351 detects the capacitance of the mixture of the substrate 211 and the atmosphere. When the expansion of the contact area of the substrates 211 and 213 progresses to the end of the substrates 211 and 213 and ends, the end face of the substrate 211 faces the electrode 351 and the capacitance of the substrate 211 is detected by the electrode 351 . Therefore, when the determination unit 150a detects the capacitance of the substrate 211 from the result of detecting the electrostatic characteristics between the electrodes 351, it can determine that the expansion of the contact area 215 is completed, that is, the bonding of the substrates is completed. can.

In this embodiment, a plurality of electrodes 351 of the bonding detection device 350 are arranged on the sides of the substrates 211 and 213 facing the end surfaces thereof. When detecting the electrostatic characteristics of a plurality of electrodes 351 facing the surfaces of the substrates 211 and 213, the oxide films formed on the surfaces of the substrates 211 and 213 cause the electrostatic characteristics to differ depending on the substrate or on the same substrate. Since it can vary from place to place, it is difficult to uniformly detect the expansion of the contact area of the substrates 211 and 213 using a plurality of electrodes 351 for all substrates or for all locations on a single substrate. On the other hand, when the electrodes 351 face the end surfaces of the substrates 211 and 213, the oxide films on the surfaces of the substrates 211 and 213 hardly affect the electrostatic properties. It becomes possible to uniformly detect the expansion of the contact area for all substrates and for all locations on a single substrate.

In this embodiment, one of the two electrodes 351a to 351e included in each of the plurality of electrode pairs 351A to 351E of the bonding detection device 350 may be shared. In such a case, the bonding detection device 350 rotates the shared electrode to face the other of the two electrodes 351a to 351e included in each of the plurality of electrode pairs 351A to 351E. and an electrode shared by the rotating mechanism is opposed to the other electrode of the two electrodes 351a to 351e included in one of the plurality of electrode pairs 351A to 351E, and the electrode 351a to be the pair. 351e to the detection unit 353 are provided. Thereby, it is possible to arrange the plurality of electrode pairs 351A to 351E without interfering with each other.

In addition, in the bonding detection apparatus 350 according to the present embodiment, the centers of the substrates 211 and 213 are brought into contact with each other to form the contact region 215 as the starting point of bonding. , 213, but may be any position, for example, the edges of the substrates 211, 213. FIG.

In the bonding detection device 350 according to the present embodiment, the two electrodes included in the plurality of electrodes 351 are arranged so as to sandwich the substrates 211 and 213 in the plane direction in a non-contact manner. In combination, the substrates 211 and 213 may be arranged so as to sandwich them in the overlapping direction.

15A and 15B schematically show the top and side configurations of a bonding detection device 350A according to the first modification, respectively. Here, FIG. 15B is a cross-sectional view along the reference line BB in FIG. 15A. Note that the holder 221 and the upper stage 322 are omitted in FIG. 15A. In FIG. 15B, holders 221 and 223 are omitted. The bonding detection device 350A includes an electrode pair 351A, and two electrodes 351a included therein are provided at the center of the lower surface of the upper stage 322 and the center of the upper surface of the lower stage 332, respectively. By detecting the electrostatic characteristics of the electrode pair 351A, it is detected whether or not the contact area 215, which is the starting point of bonding, is formed at the center of the substrates 211 and 213 respectively held by the upper stage 322 and the lower stage 332. be able to.

FIGS. 16A and 16B schematically show the top and side configurations of a bonding detection device 350B according to a second modification, respectively. Here, FIG. 16B is a cross-sectional view along the reference line BB in FIG. 16A. Note that the holder 221 and the upper stage 322 are omitted in FIG. 16A. In FIG. 16B, holders 221 and 223 are omitted. The bonding detection device 350B includes a plurality of electrode pairs 351B-351E. One of the two electrodes 351b to 351e included in each of the electrode pairs 351B to 351E is provided at four edges on the lower surface of the upper stage 322, and the other is provided at four locations on the upper surface of the lower stage 332. located at the edge. By detecting the electrostatic characteristics of each of the electrode pairs 351B to 351E, the electrodes 211 and 213 formed between the substrates 211 and 213 at four edges of the substrates 211 and 213 held by the upper stage 322 and the lower stage 332, respectively. It is possible to detect the expansion process of the contact area 215 and the completion of bonding.

15B and 16B show examples in which one electrode pair 351A or a plurality of electrode pairs 351B to 351E are provided on each of the upper stage 322 and the lower stage 332, but holders 221 and 223 are used. In some cases, the holders 221 and 223 may be provided with one electrode pair 351A or a plurality of electrode pairs 351B-351E.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the scope of claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

The execution order of each process such as actions, procedures, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is particularly "before", "before etc., and it should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the specification, and the drawings, even if the description is made using "first," "next," etc. for the sake of convenience, it means that it is essential to carry out in this order. not a thing

DESCRIPTION OF SYMBOLS 100... Substrate bonding system, 110... Case, 120, 130... Substrate cassette, 140... Transfer apparatus, 150... Control apparatus, 150a... Judgment part, 150b... Control part, 210, 211, 213... Substrate, 230... Paste Laminated substrate (substrate) 212 Scribe line 214 Notch 215 Contact area 216 Circuit area 218 Alignment mark 220, 221, 223 Holder 222, 224 Holding surface 232 Bonding wave DESCRIPTION OF SYMBOLS 300... Bonding apparatus, 310... Frame, 312... Bottom plate, 314... Support, 316... Top plate, 322... Upper stage, 324, 334... Microscope, 326, 336... Activation device, 331... X-direction drive unit, 332 Lower stage 333 Y-direction driving section 336 Activating device 338 Elevating driving section 341 Interferometer 350, 350A, 350B Bonding detector 351 Electrode 351A to 351H Electrode pairs , 351a to 351h electrodes, 352 electrode driving device, 353, 353a to 353e detector, 354 selector, 355, 356, 357 guide, 400 holder stocker, 500 pre-aligner.

Claims (20)

A substrate bonding apparatus for bonding a first substrate and a second substrate,
a pair of electrodes sandwiching at least one of the first substrate and the second substrate;
a detection unit that detects electrostatic properties between the pair of electrodes;
A substrate bonding apparatus comprising: 2. The substrate according to claim 1, wherein said pair of electrodes are arranged to sandwich said first substrate and said second substrate in a planar direction of a bonding surface of said first substrate and said second substrate. lamination device. At least one of the pair of electrodes has an electrode surface facing an end surface of at least one of the first substrate and the second substrate, and the electrode surface faces the first substrate and the second substrate. 3. The substrate bonding apparatus according to claim 2, wherein the substrates have a shape whose width changes along the direction in which the substrates are stacked. 4. The substrate bonding apparatus according to claim 2, wherein at least one of said pair of electrodes is arranged to be inclined with respect to a direction intersecting said surface direction. The pair of electrodes are arranged to face each other on sides of the first substrate and the second substrate with respect to the plane direction, with a contact region between the first substrate and the second substrate interposed therebetween. 5. The substrate bonding apparatus according to any one of claims 2 to 4. 6. The substrate bonding apparatus according to claim 5, wherein said detection unit has a guide that allows said pair of electrodes to move in the circumferential direction of said first substrate and said second substrate. The pair of electrodes are provided on the edges of the first substrate and the second substrate spaced apart from the contact area between the first substrate and the second substrate in a first direction parallel to the plane direction. 5. The substrate bonding apparatus according to any one of claims 2 to 4, arranged to face each other across a second direction that intersects with the first direction. 8. The substrate bonding apparatus according to claim 7, wherein said detection unit has a guide that allows said pair of electrodes to move in said first direction. a pair of first electrodes arranged facing each other on sides of the first substrate and the second substrate with a contact region between the first substrate and the second substrate interposed therebetween; a pair of second electrodes disposed facing each other on sides of the first substrate and the second substrate with edges of the first substrate and the second substrate interposed therebetween;
9. The substrate bonding apparatus according to claim 2, wherein said pair of first electrodes has an electrode surface larger than said pair of second electrodes. A plurality of electrode pairs including the pair of electrodes,
The substrate bonding apparatus according to any one of claims 1 to 9, wherein the detector detects electrostatic properties using AC signals of different frequencies for each of the plurality of electrode pairs. 11. The substrate bonding apparatus according to claim 1, further comprising a selector that selects and rearranges said pair of electrodes from among a plurality of electrode pairs. 12. The substrate bonding apparatus according to any one of claims 1 to 11, further comprising an electrode driving device for retracting said pair of electrodes from sides of said first substrate and said second substrate. 13. The apparatus according to any one of claims 1 to 12, further comprising a determination unit that determines a state of a contact area between the first substrate and the second substrate based on detection results of the electrostatic properties. Substrate bonding equipment. 14. The substrate bonding method according to any one of claims 1 to 13, further comprising a controller that controls tilt of at least one of said first substrate and said second substrate based on a detection result of said electrostatic properties. alignment device. At least one of the pair of electrodes is arranged on the back side of the first substrate after the first substrate is bonded to the second substrate, or the first substrate is the arranged at a position facing the first substrate after being bonded to the second substrate and not facing the first substrate before the first substrate is bonded to the second substrate; The substrate bonding apparatus according to any one of claims 1 to 13. A substrate bonding method for bonding a first substrate and a second substrate, comprising:
forming contact regions between the first substrate and the second substrate, portions of which are in contact with each other;
enlarging the contact area;
detecting an electrostatic property between a pair of electrodes sandwiching at least one of the first substrate and the second substrate;
A substrate bonding method comprising: 17. The substrate bonding method according to claim 16, wherein the pair of electrodes are arranged in a plane direction of bonding surfaces of the first substrate and the second substrate, sandwiching the first substrate and the second substrate. alignment method. 18. The substrate bonding method according to claim 16, further comprising the step of detecting alignment marks of said first substrate and said second substrate prior to the step of arranging said pair of electrodes. 19. The substrate bonding method according to any one of claims 16 to 18, further comprising determining a state of said contact area based on a detection result of said electrostatic property. 20. The substrate bonding according to any one of claims 16 to 19, further comprising controlling tilt of at least one of said first substrate and said second substrate based on the detection result of said electrostatic properties. Method.

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