Substrate bonding apparatus

Abstract

To provide a substrate joining device capable of aligning a pair of substrates to be joined even when an alignment mark arranged on the substrate cannot be imaged.SOLUTION: In the substrate joining device 1, when the alignment marks (AM1 and AM2) cannot be detected in the images captured by the alignment mark imaging units (711a and 711b), the joining unit control unit 80 estimates the positions of the alignment marks (AM1 and AM2) based on the information of the peripheral feature portion F stored in the storage unit 80a, and performs the alignment processing for performing the alignment for joining the pair of substrates W based on the estimated positions of the alignment marks (AM1 and AM2).SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a substrate bonding apparatus, and more particularly to a substrate bonding apparatus including an alignment mark imaging unit that captures an image of an alignment mark arranged on a substrate. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a substrate bonding apparatus that includes an alignment mark imaging unit that captures an image of an alignment mark arranged on a substrate (see, for example, Patent Document 1).

[0003] The substrate bonding apparatus (substrate bonding apparatus) described in Patent Document 1 includes a movable stage and a fixed stage disposed above the movable stage. A substrate is held on the upper surface of the movable stage, and a substrate to be bonded to the substrate held on the movable stage is held on the lower surface of the fixed stage. Alignment marks for alignment are disposed on the substrates held on the movable stage and the fixed stage. The substrate bonding apparatus described in Patent Document 1 also includes an upper microscope that images the alignment marks of the substrates held on the upper surface of the movable stage from above, and a lower microscope that images the alignment marks of the substrates held on the lower surface of the fixed stage from below. In the substrate bonding apparatus described in Patent Document 1, the movable stage is moved based on images of the alignment marks captured by the upper microscope and the lower microscope, and the substrates held on the movable stage and the fixed stage are aligned. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-85526 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional substrate bonding apparatus described in Patent Document 1, the fields of view of the upper microscope and the lower microscope are relatively narrow, so the alignment mark may fall outside the field of view of at least one of the upper microscope (alignment mark imaging unit) and the lower microscope (alignment mark imaging unit). In this case, the alignment mark cannot be imaged, which poses a problem of making it impossible to align the substrate held on the moving stage with the substrate held on the fixed stage.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a substrate bonding device that is capable of aligning a pair of substrates to be bonded even if the alignment marks placed on the substrates are out of the field of view of the alignment mark imaging unit. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a substrate bonding apparatus according to one aspect of the present invention comprises a pair of stages each holding a pair of substrates to be bonded to each other; an alignment mark imaging unit that images at least one of the alignment marks arranged on the pair of substrates; a memory unit that stores information on peripheral feature portions including at least one of a peripheral pattern arranged around the alignment mark on the substrate and a substrate shape portion related to the shape of the substrate; a movement mechanism that changes the relative position of the stage and the alignment mark imaging unit; and a control unit that detects the alignment mark in the image captured by the alignment mark imaging unit; if the alignment mark cannot be detected in the image captured by the alignment mark imaging unit, the control unit estimates the position of the alignment mark based on the information on the peripheral feature portions stored in the memory unit, and performs an alignment process to align the pair of substrates for bonding based on the estimated position of the alignment mark.

[0008] According to one aspect of the present invention, the substrate bonding apparatus estimates the position of the alignment mark based on the information on the peripheral feature portion stored in the memory unit, even if the alignment mark falls outside the field of view of the alignment mark imaging unit. As a result, even if the alignment mark placed on the substrate falls outside the field of view of the alignment mark imaging unit, the pair of substrates to be bonded can be aligned based on the estimated position of the alignment mark.

[0009] In the substrate bonding apparatus according to the above aspect, preferably, the pair of substrates includes a first substrate and a second substrate, the alignment marks include a first alignment mark arranged on the first substrate and a second alignment mark arranged on the second substrate, the alignment mark imaging unit includes a first alignment mark imaging unit that images the first alignment mark and a second alignment mark imaging unit that images the second alignment mark, and the control unit, in at least one of a case where the first alignment mark cannot be detected in an image captured by the first alignment mark imaging unit and a case where the second alignment mark cannot be detected in an image captured by the second alignment mark imaging unit, estimates the position of at least one of the first alignment mark and the second alignment mark based on information of the surrounding feature parts stored in the memory unit, and performs an alignment process to align the first substrate and the second substrate for bonding. With this configuration, even if at least one of the first alignment mark and the second alignment mark cannot be detected in a substrate bonding device in which a first substrate and a second substrate are bonded, the first substrate and the second substrate can be aligned based on the estimated position of at least one of the first alignment mark and the second alignment mark.

[0010] In this case, preferably, the control unit executes the alignment process in a state in which the coordinate systems of the first alignment mark or estimated first alignment mark imaged by the first alignment mark imaging unit and the second alignment mark or estimated second alignment mark imaged by the second alignment mark imaging unit are aligned to a common reference coordinate system. With this configuration, even if the coordinate system of the imaged or estimated first alignment mark and the coordinate system of the imaged or estimated second alignment mark do not match, these coordinate systems are aligned to a common reference coordinate system, so that the alignment process can be executed appropriately.

[0011] In the substrate bonding apparatus according to the above aspect, preferably, the control unit executes alignment processing based on the estimated alignment mark positions in the case of a first condition in which the accuracy of the estimated alignment mark positions is high, and executes error processing in the case of a second condition in which the accuracy of the estimated alignment mark positions is low. With this configuration, the alignment mark positions are estimated with high accuracy in the case of the first condition in which the accuracy of the estimated alignment mark positions is high, and therefore the alignment processing can be executed appropriately based on the estimated alignment mark positions. On the other hand, in the case of the second condition in which the accuracy of the estimated alignment mark positions is low, the alignment mark positions are not estimated with high accuracy, and therefore, if the alignment processing is executed based on the estimated alignment mark positions, the alignment processing cannot be executed appropriately. Therefore, by executing error processing in the case of the second condition, it is possible to prevent inappropriate alignment processing from being executed.

[0012] In this case, preferably, the first condition is that the distance between the estimated alignment mark position and the center of the field of view of the alignment mark imaging unit is less than a predetermined distance, and the second condition is that the distance is greater than the predetermined distance.

[0013] In the substrate bonding apparatus that performs alignment processing under the first condition and error processing under the second condition, preferably, a plurality of alignment marks are arranged on the substrate, and the first condition is when the number of alignment marks imaged and detected by the alignment mark imaging unit is equal to or greater than a predetermined number or the proportion of alignment marks imaged and detected by the alignment mark imaging unit is equal to or greater than a predetermined proportion, and the second condition is when the number is less than a predetermined number or the proportion is less than a predetermined proportion. With this configuration, under the first condition, a relatively large number of alignment marks are imaged by the alignment mark imaging unit (the number or proportion of alignment marks that cannot be detected but are estimated is relatively small), resulting in a relatively small positional deviation of the substrate. In this case, the alignment processing can be appropriately performed based on the estimated positions of the alignment marks. Therefore, under the first condition, the alignment processing is performed based on the estimated positions of the alignment marks. On the other hand, under the second condition, a relatively small number of alignment marks are imaged by the alignment mark imaging unit, resulting in a relatively large positional deviation of the substrate. In this case, the alignment process cannot be performed appropriately based on the estimated alignment mark position. Therefore, in the case of the second condition, the error process is performed to prevent the inappropriate alignment process from being performed.

[0014] In the substrate bonding apparatus that performs the alignment process under the first condition and performs the error process under the second condition, the error process preferably includes any one of: changing the relative position of the alignment mark image capture unit and the alignment mark using the movement mechanism based on the estimated alignment mark position, and then performing a process of having the alignment mark image capture unit capture an image of the alignment mark again; stopping the substrate bonding apparatus; and displaying a warning on the display unit that the accuracy of the estimated alignment mark position is low. The error process involves performing a process of having the alignment mark image capture unit capture an image of the alignment mark again, thereby allowing the alignment process to be performed appropriately based on the captured alignment mark. Stopping the substrate bonding apparatus as the error process prevents inappropriate alignment process from being performed based on an inaccurate estimated alignment mark position. The error process involves displaying a warning on the display unit that the accuracy of the estimated alignment mark position is low, thereby prompting the user to check the substrate, for example.

[0015] In the substrate bonding apparatus according to the above aspect, the peripheral pattern is preferably formed with the same positional accuracy as the alignment mark. With this configuration, the positional accuracy of the peripheral pattern is relatively high, so the position of the alignment mark can be accurately estimated based on the peripheral pattern. Therefore, the alignment process can be performed appropriately. Note that the term "same positional accuracy" is a concept that includes the meaning of the same positional accuracy and the meaning of not exactly the same but being of the same degree (approximately the same) of positional accuracy.

[0016] The substrate bonding apparatus according to the above aspect preferably further includes an alignment mark high-magnification imaging unit having an imaging magnification higher than that of the alignment mark imaging unit, and the control unit changes the relative position of the alignment mark and the alignment mark high-magnification imaging unit using the movement mechanism based on the estimated position of the alignment mark so that the alignment mark falls within the imaging range of the alignment mark high-magnification imaging unit, and causes the alignment mark high-magnification imaging unit to image the alignment mark, thereby executing the alignment process. With this configuration, the alignment mark is imaged more accurately by the alignment mark high-magnification imaging unit, and the alignment process can be executed more accurately based on the image of the alignment mark imaged more accurately.

[0017] In the substrate bonding apparatus according to the above aspect, the memory unit preferably stores in advance information on the positional relationship between the alignment mark and at least one of the peripheral pattern and the substrate shape portion included in the information on the peripheral feature portion. With this configuration, the control unit can easily estimate the position of the alignment mark by referring to the information on the positional relationship between the alignment mark and at least one of the peripheral pattern and the substrate shape portion stored in advance in the memory unit.

[0018] In the substrate bonding apparatus according to the above aspect, the substrate shape portion preferably includes at least one of an edge, a notch, and an orientation flat of the substrate. With this configuration, the edge, the notch, and the orientation flat of the substrate are shapes that the substrate originally has, so it is possible to omit a step of separately forming a substrate shape portion on the substrate that serves as a marker for estimating the position of the alignment mark. [Effects of the Invention]

[0019] According to the present invention, as described above, even if images of the alignment marks arranged on the substrates cannot be captured, it is possible to align the pair of substrates to be bonded. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a block diagram showing the configuration of a substrate bonding apparatus according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the configuration of the joining unit according to the first embodiment. [Figure 3] FIG. 3 is a side view of the upper stage (first stage) of the joining unit according to the first embodiment. [Figure 4] FIG. 2 is a side view of an upper stage (first stage) and a lower stage (second stage) of the joining unit according to the first embodiment. [Figure 5] FIG. 2 is a top view of an upper stage (stage) of the joining unit according to the first embodiment. [Figure 6] FIG. 4 is a diagram showing an upper reference mark according to the first embodiment. [Figure 7] FIG. 3 is a top view of a lower stage (stage) of the joining unit according to the first embodiment. [Figure 8] FIG. 4 is a diagram showing a lower reference mark according to the first embodiment. [Figure 9] FIG. 2 is a top view of an upper stage of the joining unit according to the first embodiment. [Figure 10] FIG. 2 is a top view of a first substrate (upper substrate). [Figure 11] FIG. 2 is a diagram showing upper alignment marks (first alignment marks) arranged on a first substrate. [Figure 12] FIG. 2 is a top view of a second substrate (lower substrate). [Figure 13] FIG. 10 is a diagram showing lower alignment marks (second alignment marks) arranged on a second substrate. [Figure 14] 10A and 10B are diagrams showing a peripheral feature portion including a peripheral pattern of a first substrate, a field of view of a lower wide-field alignment mark imaging unit, and an upper alignment mark according to the first embodiment. [Figure 15] 10A and 10B are diagrams showing a peripheral feature portion including a peripheral pattern of a second substrate according to the first embodiment, the field of view of an upper-side wide-field alignment mark imaging unit, and a lower-side alignment mark. [Figure 16]4 is a flowchart showing a process flow of the substrate bonding apparatus according to the first embodiment. [Figure 17] 10 is a flowchart of an alignment mark / reference mark detection step (step of detecting a lower alignment mark and a lower reference mark) in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 18] FIG. 10 is a diagram for explaining an alignment mark / reference mark detection step (a step of detecting a lower alignment mark and a lower reference mark) in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 19] 10 is a flowchart of an alignment mark / reference mark detection step (step of detecting an upper alignment mark and an upper reference mark) in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 20] FIG. 10 is a diagram for explaining an alignment mark / reference mark detection step (a step of detecting an upper alignment mark and an upper reference mark) in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 21] FIG. 4 is a diagram for explaining an alignment step in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 22] FIG. 2 is a diagram showing the coordinate system of the upper alignment marks, the coordinate system of the lower alignment marks, and a common reference coordinate system (the coordinate system of the lower stage) according to the first embodiment. [Figure 23] FIG. 3 is a diagram for explaining a substrate bonding step in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 24] FIG. 4 is a diagram for explaining an inspection step in the processing flow of the substrate bonding apparatus according to the first embodiment. [Figure 25] 10 is a flowchart of an alignment mark / reference mark detection step (step of detecting a lower alignment mark and a lower reference mark) in the process flow of the substrate bonding apparatus according to the second embodiment. [Figure 26] 10 is a flowchart of an alignment mark / reference mark detection step (step of detecting an upper alignment mark and an upper reference mark) in the processing flow of the substrate bonding apparatus according to the second embodiment. [Figure 27] 11 is a flowchart of an alignment mark / reference mark detection step (step of detecting a lower alignment mark and a lower reference mark) in the process flow of the substrate bonding apparatus according to the third embodiment. [Figure 28] 11 is a flowchart of an alignment mark / reference mark detection step (step of detecting an upper alignment mark and an upper reference mark) in the process flow of the substrate bonding apparatus according to the third embodiment. [Figure 29] FIG. 10 is a diagram showing a state in which a warning is displayed on the display unit to the effect that the accuracy of the alignment mark position estimated as error processing according to the first modified example is low. [Figure 30] 10A and 10B are diagrams showing the edge, orientation flat, and notch of a substrate as substrate shape parts relating to the shape of a substrate according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] [First embodiment] The configuration of a substrate bonding apparatus 1 according to a first embodiment will be described with reference to Figure 1. In the following description, the vertical direction is referred to as the Z direction. The upward direction is referred to as the Z1 direction, and the downward direction is referred to as the Z2 direction. The direction perpendicular to the Z direction is referred to as the X direction. One side of the X direction is referred to as the X1 direction, and the other side is referred to as the X2 direction. The direction perpendicular to the Z direction and the X direction is referred to as the Y direction. One side of the Y direction is referred to as the Y1 direction, and the other side is referred to as the Y2 direction.

[0023] The substrate bonding apparatus 1 is an apparatus that bonds a first substrate W1 (upper substrate) and a second substrate W2 (lower substrate). Note that hereinafter, the first substrate W1 and the second substrate W2 are collectively referred to as substrates W. The substrate W is made of a silicon wafer, a compound semiconductor wafer, a glass substrate, or the like, and may have elements formed thereon. As shown in FIG. 1, the substrate bonding apparatus 1 includes a bonding unit 5 and a display unit 31. In addition to these, the substrate bonding apparatus 1 may also include a plasma processing unit for activating the surface of the substrate W, a cleaning unit for cleaning the surface of the substrate W with a cleaning liquid, and a transfer robot for transporting the substrate W between each unit.

[0024] (Connection unit) Next, the structure of the joint unit 5 will be described in detail with reference to FIGS.

[0025] As shown in FIG. 2, the bonding unit 5 includes an upper stage 51, a lower stage 61, and a base 70. The bonding unit 5 also includes an alignment mark imaging unit 71, a reference mark imaging unit 72, and an inspection imaging unit 73. The bonding unit 5 also includes a bonding unit control unit 80. The bonding unit 5 is housed, for example, in a chamber. The upper stage 51 and the lower stage 61 are an example of a "pair of stages" in the claims. The bonding unit control unit 80 is an example of a "control unit" in the claims.

[0026] The pedestal 70 supports the upper stage 51 and the lower stage 61. The pedestal 70 is disposed, for example, on the floor of a clean room in which the substrate bonding apparatus 1 is disposed. As shown in FIG. 3, the upper stage 51 is supported by the pedestal 70 via a gate-shaped frame 64. Specifically, a Z-direction linear motor 64a is attached to each of two pillars of the frame 64, and a shaft 65b is attached to the Z-direction linear motor 64a. The upper stage 51 is supported by the shaft 65b. The Z-direction linear motor 64a attached to the frame 64 moves the shaft 65b in the Z direction, thereby raising and lowering the upper stage 51 in the Z direction. In addition, a rotation motor 65a is provided on the shaft 65b, and the upper stage 51 can be turned upside down by driving the rotation motor 65a.

[0027] As shown in FIG. 4, the upper stage 51 includes an upper chuck 51a, an upper rotation motor 51b, an upper base portion 51c, an upper stacking portion 51d, and an upper reference mark MA1.

[0028] The upper chuck 51a is, for example, a vacuum chuck or an electrostatic chuck. As shown in FIG. 5, the upper chuck 51a has, for example, a disk shape. As shown in FIG. 4, the upper rotation motor 51b is an electric motor that rotates the disk-shaped upper chuck 51a around a central axis L1. The upper base unit 51c supports the upper chuck 51a and the upper stack unit 51d. The upper base unit 51c can be inverted by rotating around an axis L2.

[0029] As shown in FIG. 5, the upper reference marks MA1 are disposed on the upper stage 51. For example, four upper reference marks MA1 are disposed on the surface of the upper stack 51d. The upper reference marks MA1 are formed on a transparent quartz plate member 51e. For example, two of the four upper reference marks MA1 are formed on one rectangular plate member 51e. The remaining two upper reference marks MA1 are each formed on one square plate member 51e. The four upper reference marks MA1 are disposed at the four corners of the square-shaped upper stack 51d. As shown in FIG. 6, the upper reference mark MA1 is formed by, for example, two rectangular portions ma1. The two rectangular portions ma1 are diagonally spaced apart from each other.

[0030] As shown in FIG. 4, the lower stage 61 includes a lower chuck 61a, a lower rotation motor 61b, a lower base portion 61c, a lower stacking portion 61d, and a lower reference mark MA2.

[0031] As shown in FIG. 4, the lower chuck 61a is, for example, a vacuum chuck or an electrostatic chuck. The lower chuck 61a has, for example, a disk shape (see FIG. 7). The lower rotation motor 61b is an electric motor that rotates the disk-shaped lower chuck 61a around the central axis L3 as shown in FIG. 4. The lower base unit 61c supports the lower chuck 61a and the lower stack unit 61d. The lower base unit 61c has, for example, a box shape. The lower base unit 61c is supported by an XY stage 62 (see FIG. 2). As shown in FIG. 2, the XY stage 62 changes the relative position between the upper stage 51 and a lower alignment mark imaging unit 71b (described later). The XY stage 62 also changes the relative position between the lower stage 61 and an upper alignment mark imaging unit 71a (described later). The XY stage 62 includes an X-direction linear slider 62a and a Y-direction linear slider 62b. The X-direction linear slider 62a moves the lower stage 61 along the X direction, and the Y-direction linear slider 62b moves the lower stage 61 along the Y direction. The XY stage 62 is an example of a "moving mechanism" in the claims.

[0032] As shown in FIG. 7, the lower reference marks MA2 are arranged on the lower stage 61. For example, four lower reference marks MA2 are arranged on the surface of the lower stacked portion 61d. The lower reference marks MA2 are formed on a transparent plate member 61e made of quartz. For example, two of the four lower reference marks MA2 are formed on one rectangular plate member 61e. The remaining two lower reference marks MA2 are each formed on one square plate member 61e. The four lower reference marks MA2 are arranged at the four corners of the square-shaped lower stacked portion 61d. Also, as shown in FIG. 8, the lower reference marks MA2 are formed, for example, by cross-shaped portions ma2.

[0033] 2, the alignment mark imaging unit 71 is configured to capture images of alignment marks (upper alignment mark AM1 and lower alignment mark AM2, which will be described later) arranged on the substrate W. The alignment mark imaging unit 71 is, for example, a microscope camera that captures visible light. The alignment mark imaging unit 71 also includes an upper alignment mark imaging unit 71a and a lower alignment mark imaging unit 71b.

[0034] The upper alignment mark imaging unit 71a is attached to the gate-shaped frame 63. The upper alignment mark imaging unit 71a is arranged so that its imaging direction faces the Z2 direction (downward). The upper alignment mark imaging unit 71a images the lower alignment mark AM2 (see FIG. 12) arranged on the second substrate W2 (lower substrate) held by the lower stage 61. The upper alignment mark imaging unit 71a also includes an upper wide-field alignment mark imaging unit 711a and an upper narrow-field alignment mark imaging unit 712a. The upper narrow-field alignment mark imaging unit 712a has a narrower imaging range than the upper wide-field alignment mark imaging unit 711a, but is able to image the lower alignment mark AM2 with higher accuracy. The upper wide-field alignment mark imaging section 711a is an example of the "alignment mark imaging section" and "second alignment mark imaging section" in the claims.

[0035] The lower-side alignment mark imaging unit 71b is attached to the Y-direction linear slider 62b of the XY stage 62. As a result, the lower-side alignment mark imaging unit 71b moves in the Y direction together with the Y-direction linear slider 62b. The lower-side alignment mark imaging unit 71b is disposed so that its imaging direction faces the Z1 direction (upward). The lower-side alignment mark imaging unit 71b images the upper alignment mark AM1 (see FIG. 10) disposed on the first substrate W1 (upper substrate) held by the upper stage 51. The lower-side alignment mark imaging unit 71b also includes a lower-side wide-field alignment mark imaging unit 711b and a lower-side narrow-field alignment mark imaging unit 712b. While the lower-side narrow-field alignment mark imaging unit 712b has a narrower imaging range than the lower-side wide-field alignment mark imaging unit 711b, it can image the upper alignment mark AM1 with higher accuracy. The lower wide-field alignment mark imaging section 711b is an example of the "alignment mark imaging section" and "first alignment mark imaging section" in the claims.

[0036] The reference mark imaging unit 72 images the upper reference mark MA1 and the lower reference mark MA2 from the vertical direction in a state in which the upper stage 51 and the lower stage 61 are arranged so that the upper reference mark MA1 and the lower reference mark MA2 overlap when viewed from the Z direction (vertical direction) (see FIG. 4). The reference mark imaging unit 72 is, for example, a visible light camera.

[0037] A plurality of reference mark imaging units 72 are arranged. As shown in FIG. 9, for example, three reference mark imaging units 72 are arranged. The three reference mark imaging units 72 are arranged on the back surface side (see FIG. 4) of the upper base unit 51c of the upper stage 51. The back surface side of the upper base unit 51c means the side opposite to the side on which the first substrate W1 (upper substrate) is held. The three reference mark imaging units 72 are arranged at three corners of the square-shaped upper base unit 51c. As shown in FIG. 4, the reference mark imaging units 72 are arranged so as to penetrate the upper base unit 51c and the upper stack unit 51d of the upper stage 51. The upper reference mark MA1 is arranged at the end where the reference mark imaging unit 72 penetrates the upper stack unit 51d. This allows the reference mark imaging unit 72 to capture an image of the upper reference mark MA1. Furthermore, the three reference mark imaging units 72 each capture images of three of the four upper reference marks MA1.

[0038] 2, the inspection imaging unit 73 images the first substrate W1 (upper substrate) and the second substrate W2 (lower substrate) in a bonded state. The inspection imaging unit 73 is, for example, an infrared camera. The inspection imaging unit 73 is attached to the gate-shaped frame 63.

[0039] 2, the bonding unit control unit 80 includes a processor such as a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The bonding unit control unit 80 controls the operation of the bonding unit 5. The bonding unit control unit 80 includes a storage unit 80a. The storage unit 80a is, for example, a flash memory, a solid state drive, or a hard disk. The storage unit 80a stores programs to be executed by the bonding unit control unit 80.

[0040] (substrate) The structure of the substrate W will be described.

[0041] As shown in FIG. 10, the first substrate W1 (upper substrate) has a disk shape. A V-shaped notch N is formed in the first substrate W1. Note that an orientation flat O (see FIG. 30) may be formed instead of the notch N. The notch N and the orientation flat O are intended to indicate the crystal orientation of the first substrate W1. Also, an upper alignment mark AM1 is arranged on the first substrate W1. A plurality of upper alignment marks AM1 are arranged as shown in FIG. 10. Although FIG. 10 illustrates approximately 50 upper alignment marks AM1, for example, approximately 100 upper alignment marks AM1 may be arranged. Note that the number of upper alignment marks AM1 is not limited to approximately 100. Also, although FIG. 10 illustrates multiple upper alignment marks AM1 arranged in a matrix (row and column), the arrangement of multiple upper alignment marks AM1 is not limited to a matrix. 11, the upper alignment mark AM1 is configured, for example, with a cross-shaped portion am1. The upper alignment mark AM1 is an example of the "first alignment mark" in the claims.

[0042] As shown in FIG. 12, the second substrate W2 (lower substrate) has the same configuration as the first substrate W1. That is, the second substrate W2 has a disk shape. A V-shaped notch N is formed in the second substrate W2. Note that an orientation flat O (see FIG. 30) may be formed instead of the notch N. Also, lower alignment marks AM2 are arranged on the second substrate W2. A plurality of lower alignment marks AM2 are arranged as shown in FIG. 12. Although approximately 50 lower alignment marks AM2 are illustrated in FIG. 12, for example, approximately 100 lower alignment marks AM2 are arranged. Note that the number of lower alignment marks AM2 is not limited to approximately 100. Also, although the plurality of lower alignment marks AM2 are arranged in a matrix (row and column) in FIG. 12, the arrangement of the plurality of lower alignment marks AM2 is not limited to a matrix. 13, the lower alignment mark AM2 is made up of, for example, four L-shaped portions am2. The lower alignment mark AM2 is an example of the "second alignment mark" in the claims.

[0043] Next, the surrounding characteristic portion F stored in the storage unit 80a will be described with reference to FIGS.

[0044] In the first embodiment, as shown in FIGS. 14 and 15 , the storage unit 80a stores information about a peripheral feature portion F including peripheral patterns PT arranged around alignment marks (upper alignment mark AM1, lower alignment mark AM2) on the substrate W. The peripheral patterns PT are, for example, mask patterns (circuit patterns, wiring patterns, etc.) or element chips. For example, a plurality of peripheral patterns PT (greater than the number of upper alignment marks AM1 and lower alignment marks AM2) are arranged. Furthermore, the peripheral patterns PT are, for example, arranged across the entire surface of the substrate W. The peripheral patterns PT are respectively arranged on the first substrate W1 (upper substrate) shown in FIG. 14 and the second substrate W2 (lower substrate) shown in FIG. 15. Furthermore, the peripheral feature portion F includes a plurality of peripheral patterns PT enclosed within a two-dot chain rectangle shown in FIGS. 14 and 15 . It should be noted that the upper alignment mark AM1 and the lower alignment mark AM2, which are depicted within the two-dot chain line rectangle, are not included in the peripheral feature portion F.

[0045] In the first embodiment, the memory unit 80a pre-stores information on the positional relationship (position coordinates) between the peripheral pattern PT and the alignment mark as information on the peripheral feature portion F. The positional relationship refers to, for example, how much the X and Y coordinates of a specific alignment mark are shifted from the specific peripheral pattern PT. In FIG. 14, the dotted square surrounding the peripheral pattern PT represents the field of view of the lower-side wide-field alignment mark imaging unit 711b, and P11 represents the center of the field of view of the lower-side wide-field alignment mark imaging unit 711b. In FIG. 15, the dotted square surrounding the peripheral pattern PT represents the field of view of the upper-side wide-field alignment mark imaging unit 711a, and P21 represents the center of the field of view of the upper-side wide-field alignment mark imaging unit 711a. 14 shows that on the first substrate W1 (upper substrate), the center P12 of the upper alignment mark AM1 is located at coordinates that are shifted by -x in the X direction and -y in the Y direction from the peripheral pattern PT that is located at the field of view center P11 of the lower-side wide-field alignment mark imaging unit 711b. The example shown in Fig. 15 shows that on the second substrate W2 (lower substrate), the center P22 of the lower alignment mark AM2 is located at coordinates that are shifted by -x in the X direction and -y in the Y direction from the peripheral pattern PT that is located at the field of view center P21 of the upper-side wide-field alignment mark imaging unit.

[0046] Furthermore, the peripheral pattern PT is formed with the same positional accuracy as the upper alignment mark AM1 and the lower alignment mark AM2. That is, the positional error of the peripheral pattern PT on the first substrate W1 is the same as the positional error of the upper alignment mark AM1 on the first substrate W1. Furthermore, the positional error of the peripheral pattern PT on the second substrate W2 is the same as the positional error of the lower alignment mark AM2 on the second substrate W2. Note that the term "same positional accuracy" is a concept that encompasses both the meaning of the same positional accuracy and the meaning of not exactly the same but being about the same (substantially the same) positional accuracy.

[0047] (Process flow of substrate bonding equipment) 16 to 24, a schematic process flow of the substrate bonding apparatus 1 will be described. Of the process flow, the alignment mark / reference mark detection step will be described in detail with reference to FIGS.

[0048] (Inversion process) The first substrate W1 and the second substrate W2 are transported to the bonding unit 5 by an external transport robot. The surfaces (bonding surfaces) of the first substrate W1 and the second substrate W2 may be hydrophilized in advance by plasma treatment, cleaning treatment, or the like. Here, the first substrate W1 (upper substrate) is held by the upper chuck 51a of the upper stage 51 facing upward. The second substrate W2 (lower substrate) is held by the lower chuck 61a of the lower stage 61 facing upward. Thereafter, in step S1 of FIG. 16, the upper stage 51 is rotated and inverted so that the upper chuck 51a faces downward.

[0049] (Alignment mark / reference mark detection process) In step S2 of Fig. 16, an alignment mark / reference mark detection process is performed. Specifically, first, in step S11 of Fig. 17, a lower alignment mark / reference mark detection process is performed as shown in Fig. 18. That is, the lower stage 61 is moved by the XY stage 62 so that the lower alignment mark AM2 of the second substrate W2 (lower substrate) held by the lower chuck 61a of the lower stage 61 faces the upper wide-field alignment mark imaging unit 711a fixed to the frame 63. Then, the lower alignment mark AM2 of the second substrate W2 is imaged by the upper wide-field alignment mark imaging unit 711a.

[0050] 17, the bonding unit control unit 80 performs an operation to detect the lower alignment mark AM2 in the image captured by the upper-side wide-field alignment mark imaging unit 711a. For example, the bonding unit control unit 80 performs an operation to detect the lower alignment mark AM2 by image processing. In the first embodiment, the bonding unit control unit 80 determines whether the lower alignment mark AM2 has been detected in the image captured by the upper-side wide-field alignment mark imaging unit 711a.

[0051] If the answer is No in step S12 (if the lower alignment mark AM2 cannot be detected), in the first embodiment, in step S13, the joining unit control unit 80 estimates the position of the lower alignment mark AM2 based on the information on the peripheral characteristic portion F stored in the memory unit 80a. For example, as shown in FIG. 15, assume that the lower alignment mark AM2 was not photographed by the upper wide-field alignment mark imaging unit 711a, but the peripheral pattern PT was photographed. The joining unit control unit 80 estimates the position of the lower alignment mark AM2 based on the positional relationship (position coordinates) between the photographed peripheral pattern PT and the lower alignment mark AM2, which is stored in the memory unit 80a. In other words, the position of the lower alignment mark AM2 is acquired indirectly from the photographed peripheral pattern PT. In the example shown in Figure 15, it is estimated that the center P22 of the lower alignment mark AM2 is located at coordinates that are shifted by -x in the X direction and -y in the Y direction from the peripheral pattern PT located at the field of view center P21 of the upper wide-field alignment mark imaging unit 711a.

[0052] 17, the joining unit control unit 80 determines whether the distance L12 between the estimated position of the lower alignment mark AM2 and the center P21 of the field of view of the upper wide-field alignment mark imaging unit 711a is equal to or less than a predetermined distance Lth. If the distance L12 between the estimated position of the lower alignment mark AM2 and the center P21 of the field of view of the upper wide-field alignment mark imaging unit 711a is equal to or less than the predetermined distance Lth (hereinafter referred to as the first condition), this indicates that the accuracy of the estimated position of the lower alignment mark AM2 is high. If the distance L12 between the estimated position of the lower alignment mark AM2 and the center P21 of the field of view of the upper wide-field alignment mark imaging unit 711a is greater than the predetermined distance Lth (hereinafter referred to as the second condition), this indicates that the accuracy of the estimated position of the lower alignment mark AM2 is low.

[0053] If the answer is No in step S14 (if the second condition is met), then in step S15 the bonding unit control section 80 executes error processing. Specifically, the bonding unit control section 80 stops the substrate bonding apparatus 1. This allows the user to approach the bonding unit 5 and check the state of the second substrate W2. Then, the user takes measures such as removing the second substrate W2, and then resumes the operation of the substrate bonding apparatus 1. Note that if the answer is Yes in step S14 (if the first condition is met), then the process proceeds to step S17.

[0054] 17, if the answer is Yes (if the lower alignment mark AM2 can be detected), the joining unit control unit 80 proceeds to step S16, where it causes the upper narrow-field alignment mark imaging unit 712a to image the lower alignment mark AM2 based on the rough position of the lower alignment mark AM2 detected from the image captured by the upper wide-field alignment mark imaging unit 711a. This allows the position of the lower alignment mark AM2 to be detected with high accuracy.

[0055] Next, the process proceeds to step S17, where the bonding unit control section 80 determines whether or not the detection process for all of the lower alignment marks AM2 arranged on the second substrate W2 has been completed. If the result in step S17 is No, the process returns to step S11.

[0056] If the answer is Yes in step S17 (if all detection processes for the lower alignment mark AM2 have been completed), the process proceeds to step S18, where the lower reference mark MA2 arranged on the lower stage 61 is imaged by the upper wide-field alignment mark imaging unit 711a, and the position (coordinates) of the lower reference mark MA2 is roughly detected. Then, based on the rough position of the lower reference mark MA2, the lower reference mark MA2 is imaged by the upper narrow-field alignment mark imaging unit 712a, and the position of the lower reference mark MA2 is detected with high accuracy. After that, the process proceeds to step S21 shown in FIG.

[0057] In step S21 of Fig. 19, an upper alignment mark / reference mark detection process is performed, as shown in Fig. 20. That is, the lower stage 61 is moved by the XY stage 62 so that the upper alignment mark AM1 of the first substrate W1 (upper substrate) held by the upper chuck 51a of the upper stage 51 faces the lower wide-field alignment mark imaging unit 711b fixed to the XY stage 62. Then, the upper alignment mark AM1 of the first substrate W1 is imaged by the lower wide-field alignment mark imaging unit 711b.

[0058] 19, the bonding unit control unit 80 performs an operation to detect the upper alignment mark AM1 in the image captured by the lower wide-field alignment mark imaging unit 711b. For example, the bonding unit control unit 80 performs an operation to detect the upper alignment mark AM1 by image processing. In the first embodiment, it is determined whether or not the upper alignment mark AM1 has been detected in the image captured by the lower wide-field alignment mark imaging unit 711b.

[0059] If the answer is No in step S22 (if the upper alignment mark AM1 cannot be detected), in the first embodiment, in step S23, the joining unit control unit 80 estimates the position of the upper alignment mark AM1 based on the information on the peripheral characteristic portion F stored in the memory unit 80a. For example, as shown in FIG. 14, assume that the upper alignment mark AM1 was not photographed by the lower wide-field alignment mark imaging unit 711b, but the peripheral pattern PT was photographed. The joining unit control unit 80 estimates the position of the upper alignment mark AM1 based on the positional relationship (position coordinates) between the photographed peripheral pattern PT and the upper alignment mark AM1, which is stored in the memory unit 80a. In other words, the position of the upper alignment mark AM1 is indirectly acquired from the photographed peripheral pattern PT. In the example shown in Figure 14, it is estimated that the center P12 of the upper alignment mark AM1 is located at coordinates that are shifted by -x in the X direction and -y in the Y direction from the peripheral pattern PT located at the field of view center P11 of the lower wide-field alignment mark imaging unit 711b.

[0060] 19, the joining unit control unit 80 determines whether the distance L11 between the estimated position of the upper alignment mark AM1 and the field of view center P11 of the lower wide-field alignment mark imaging unit 711b is equal to or less than a predetermined distance Lth. If the distance L11 between the estimated position of the upper alignment mark AM1 and the field of view center P11 of the lower wide-field alignment mark imaging unit 711b is equal to or less than the predetermined distance Lth (hereinafter referred to as the first condition), this means that the accuracy of the estimated position of the upper alignment mark AM1 is high. If the distance L11 between the estimated position of the upper alignment mark AM1 and the field of view center P11 of the lower wide-field alignment mark imaging unit 711b is greater than the predetermined distance Lth (hereinafter referred to as the second condition), this means that the accuracy of the estimated position of the upper alignment mark AM1 is low.

[0061] If the answer is No in step S24 (if the second condition is met), then in step S25 the bonding unit control section 80 executes error processing. Specifically, the bonding unit control section 80 stops the substrate bonding apparatus 1. This allows the user to approach the bonding unit 5 and check the state of the first substrate W1. Then, the user takes action such as removing the first substrate W1, and then resumes the operation of the substrate bonding apparatus 1. Note that if the answer is Yes in step S24 (if the first condition is met), then the process proceeds to step S27.

[0062] 19, if the answer is Yes (if the upper alignment mark AM1 can be detected), the joining unit control unit 80 proceeds to step S26, where it causes the lower narrow-field alignment mark imaging unit 712b to image the upper alignment mark AM1 based on the rough position of the upper alignment mark AM1 detected from the image captured by the lower wide-field alignment mark imaging unit 711b. This allows the position of the upper alignment mark AM1 to be detected with high accuracy.

[0063] Next, the process proceeds to step S27, where the bonding unit control section 80 determines whether or not the detection process for all of the upper alignment marks AM1 arranged on the first substrate W1 has been completed. If the result in step S27 is No, the process returns to step S21.

[0064] If the answer is Yes in step S27, the process proceeds to step S28, where the upper reference mark MA1 placed on the upper stage 51 is imaged by the lower wide-field alignment mark imaging unit 711b, and the position (coordinates) of the upper reference mark MA1 is roughly detected. Then, based on the rough position of the upper reference mark MA1, the upper reference mark MA1 is imaged by the lower narrow-field alignment mark imaging unit 712b, and the position of the upper reference mark MA1 is detected with high accuracy. After that, the process proceeds to the alignment process of step S3 shown in FIG.

[0065] (Alignment process) 16, the first substrate W1 (upper substrate) and the second substrate W2 (lower substrate) are aligned so as to be positioned at a horizontal joining position based on the detected positions (coordinates) of the lower alignment mark AM2, lower reference mark MA2, upper alignment mark AM1, and upper reference mark MA1, as shown in Fig. 21. Specifically, by operating the XY stage 62, the upper rotation motor 51b of the upper stage 51, and the lower rotation motor 61b of the lower stage 61, the first substrate W1 and the second substrate W2 are aligned so as to minimize positional deviation at the horizontal joining position between the first substrate W1 and the second substrate W2.

[0066] In the first embodiment, the joining unit control unit 80 performs alignment processing in a state in which the coordinate systems of the upper alignment mark AM1 or the estimated upper alignment mark AM1 imaged by the lower alignment mark imaging unit 71b (711b, 712b) and the lower alignment mark AM2 or the estimated lower alignment mark AM2 imaged by the upper alignment mark imaging unit 71a (711a, 712a) are aligned to a common reference coordinate system. As shown in Fig. 22, the coordinate system (referred to as coordinate system 1) of the upper alignment mark AM1 imaged by the lower alignment mark imaging unit 71b is different from the coordinate system (referred to as coordinate system 2) of the lower alignment mark AM2 imaged by the upper alignment mark imaging unit 71a. Therefore, the bonding unit control unit 80 executes a process of aligning the coordinate system 1 and the coordinate system 2 with a common reference coordinate system. The common reference coordinate system is, for example, a coordinate system (referred to as coordinate system 3) set on the lower stage 61. The process of aligning with the common reference coordinate system is, for example, a process of converting the coordinate systems 1 and 2. Then, the alignment process is executed with the coordinate systems 1 and 2 aligned with the coordinate system 3. Furthermore, the alignment process is executed with the coordinate system of the upper reference mark MA1 (referred to as coordinate system 4) and the coordinate system of the lower reference mark MA2 (referred to as coordinate system 5) arranged on the upper stage 51 also aligned with the common reference coordinate system.

[0067] (Substrate bonding process) In step S4, the upper stage 51 is lowered to the Z2 side by driving the Z-direction linear motor 64a, as shown in Fig. 23. As a result, the first substrate W1 and the second substrate W2 are bonded together.

[0068] (Inspection process) 24, the upper alignment mark AM1 and the lower alignment mark AM2, which overlap each other, are imaged by the inspection imaging section 73 fixed to the frame 63. The bonding unit control section 80 acquires the bonding accuracy of the first substrate W1 and the second substrate W2 based on the image acquired by the inspection imaging section 73. Then, the bonding unit control section 80 corrects the amount of movement of the first substrate W1 and the second substrate W2 when moving them relatively in the next alignment step between the first substrate W1 and the second substrate W2, based on the bonding accuracy acquired this time.

[0069] [Effects of the first embodiment] In the first embodiment, the following effects can be obtained.

[0070] In the first embodiment, even if the alignment marks (AM1, AM2) fall outside the field of view of the alignment mark imaging units (711a, 711b), the positions of the alignment marks (AM1, AM2) are estimated based on the information on the peripheral feature portion F stored in the memory unit 80a. As a result, even if the alignment marks (AM1, AM2) arranged on the substrates W fall outside the field of view of the alignment mark imaging units (711a, 711b), the pair of substrates W to be bonded can be aligned based on the estimated positions of the alignment marks (AM1, AM2).

[0071] Furthermore, in the first embodiment, if the bonding unit control unit 80 cannot detect the upper alignment mark AM1 in the image captured by the lower wide-field alignment mark imaging unit 711b and / or cannot detect the lower alignment mark AM2 in the image captured by the upper wide-field alignment mark imaging unit 711a, the bonding unit control unit 80 estimates the positions of the undetected upper alignment mark AM1 and / or lower alignment mark AM2 based on the information of the peripheral feature portion F stored in the storage unit 80a, and performs alignment processing to align the first substrate W1 and the second substrate W2 for bonding. This makes it possible to align the first substrate W1 and the second substrate W2 even if the upper alignment mark AM1 and / or lower alignment mark AM2 cannot be detected.

[0072] Furthermore, in the first embodiment, as described above, the joining unit control unit 80 performs the alignment process in a state in which the coordinate systems of the upper alignment mark AM1 or the estimated upper alignment mark AM1 imaged by the lower alignment mark imaging unit 71b and the lower alignment mark AM2 or the estimated lower alignment mark AM2 imaged by the upper alignment mark imaging unit 71a are aligned to a common reference coordinate system. As a result, even if the coordinate system of the imaged or estimated upper alignment mark AM1 and the coordinate system of the imaged or estimated lower alignment mark AM2 do not match, these coordinate systems are aligned to a common reference coordinate system, so the alignment process can be performed appropriately.

[0073] Furthermore, in the first embodiment, as described above, in the case of the first condition in which the accuracy of the estimated positions of the alignment marks (AM1, AM2) is high, the joining unit control unit 80 performs the alignment process based on the estimated positions of the alignment marks (AM1, AM2). As a result, in the case of the first condition in which the accuracy of the estimated positions of the alignment marks (AM1, AM2) is high, the positions of the alignment marks (AM1, AM2) are estimated with high accuracy, and therefore the alignment process can be performed appropriately based on the estimated positions of the alignment marks (AM1, AM2). On the other hand, in the case of the second condition in which the accuracy of the estimated positions of the alignment marks (AM1, AM2) is low, the positions of the alignment marks (AM1, AM2) are not estimated with high accuracy, and therefore, if the alignment process is performed based on the estimated positions of the alignment marks (AM1, AM2), the alignment process cannot be performed appropriately. Therefore, in the case of the second condition, by performing error processing, it is possible to prevent the alignment process from being performed inappropriately.

[0074] Furthermore, in the first embodiment, as described above, the first condition is when the separation distance (L11, L12) between the estimated positions of the alignment marks (AM1, AM2) and the field of view centers (P11, P12) of the alignment mark imaging units (711a, 711b) is equal to or less than a predetermined distance Lth, and the second condition is when the separation distance (L11, L12) is greater than the predetermined distance Lth. As a result, under the first condition, the separation distance (L11, L12) between the estimated positions of the alignment marks (AM1, AM2) and the field of view centers (P11, P12) of the alignment mark imaging units (711a, 711b) is relatively small, and therefore the positions of the alignment marks (AM1, AM2) can be estimated with high accuracy. Therefore, under the first condition, the alignment process can be performed appropriately based on the estimated positions of the alignment marks (AM1, AM2). On the other hand, under the second condition, the distance (L11, L12) between the estimated positions of the alignment marks (AM1, AM2) and the centers of the fields of view (P11, P12) of the alignment mark imaging units (711a, 711b) is relatively large, so the positions of the alignment marks (AM1, AM2) cannot be estimated with high accuracy. Therefore, under the second condition, error processing is performed to prevent inappropriate alignment processing from being performed.

[0075] Furthermore, in the first embodiment, as described above, the error processing includes stopping the substrate bonding apparatus 1. Thus, by stopping the substrate bonding apparatus 1 as the error processing, it is possible to prevent an inappropriate alignment process from being performed based on the positions of the alignment marks (AM1, AM2) estimated with low accuracy.

[0076] Furthermore, in the first embodiment, as described above, the peripheral pattern PT is formed with the same positional accuracy as the alignment marks (AM1, AM2). As a result, the positional accuracy of the peripheral pattern PT is relatively high, and therefore the positions of the alignment marks (AM1, AM2) can be estimated with high accuracy based on the peripheral pattern PT. Therefore, the alignment process can be performed appropriately.

[0077] Furthermore, in the first embodiment, as described above, the memory unit 80a pre-stores information on the positional relationship between the alignment marks (AM1, AM2) and the peripheral pattern PT included in the information on the peripheral characteristic portion F. This allows the bonding unit control unit 80 to easily estimate the positions of the alignment marks (AM1, AM2) by referring to the information on the positional relationship between the peripheral pattern PT and the alignment marks (AM1, AM2) that has been pre-stored in the memory unit 80a.

[0078] [Second embodiment] The alignment mark / reference mark detection process according to the second embodiment will be described with reference to Figures 25 and 26. Unlike the first embodiment, in which the first and second conditions were determined based on whether the separation distance (L11, L12) between the estimated positions of the alignment marks (AM1, AM2) and the field of view centers (P11, P12) of the alignment mark imaging units (711a, 711b) is equal to or less than a predetermined distance Lth, the second embodiment determines the first and second conditions based on whether the number N of imaged and detected alignment marks (AM1, AM2) is equal to or greater than a predetermined number Nth, or whether the proportion R of imaged and detected alignment marks (AM1, AM2) out of all alignment marks (AM1, AM2) that have undergone the detection process is equal to or greater than a predetermined proportion Rth.

[0079] (Alignment mark / reference mark detection process) As shown in FIG. 25, steps S11 to S13 and S16 of the alignment mark / reference mark detection process according to the second embodiment are the same as those in the first embodiment.

[0080] In step S31, similar to step S17 in the first embodiment, the bonding unit control unit 80 determines whether the detection process for all of the lower alignment marks AM2 arranged on the second substrate W2 has been completed. If the determination in step S31 is No, the process returns to step S11.

[0081] If the answer to step S31 is Yes (if all detection processes for the lower alignment marks AM2 have been completed), in step S32, the joining unit control unit 80 determines whether the number N of the lower alignment marks AM2 imaged and detected by the upper-side wide-field alignment mark imaging unit 711a is equal to or greater than a predetermined number Nth, or whether the proportion R of all alignment marks (AM1, AM2) imaged and detected by the upper-side wide-field alignment mark imaging unit 711a that have undergone the detection process is equal to or greater than a predetermined proportion Rth. The joining unit control unit 80 executes at least one of the determination of whether the number N is equal to or greater than the predetermined number Nth or the determination of whether the proportion R is equal to or greater than a predetermined proportion Rth. If the number N of the lower alignment marks AM2 imaged by the upper-side wide-field alignment mark imaging unit 711a is equal to or greater than the predetermined number Nth or the proportion R is equal to or greater than the predetermined proportion Rth (hereinafter referred to as the first condition), this means that the estimated position of the lower alignment mark AM2 is highly accurate. Furthermore, if the number N of lower alignment marks AM2 imaged by the upper wide-field alignment mark imaging unit 711a is less than a predetermined number Nth or the ratio R is less than a predetermined ratio Rth (hereinafter referred to as the second condition), it means that the accuracy of the estimated position of the lower alignment mark AM2 is low.

[0082] If the answer is No in step S32 (if the second condition is met), in step S33, the bonding unit control unit 80 executes error processing, similar to step S15 in the first embodiment. Specifically, the bonding unit control unit 80 stops the substrate bonding apparatus 1.

[0083] If the answer is Yes in step S32 (if the first condition is met), the process proceeds to step S34, where the lower reference mark MA2 arranged on the lower stage 61 is imaged by the upper alignment mark imaging unit 71a, and the position (coordinates) of the lower reference mark MA2 is detected, as in step S18 of the first embodiment. Thereafter, the process proceeds to step S21 shown in FIG.

[0084] As shown in FIG. 26, steps S21 to S23 and S26 of the alignment mark / reference mark detection process according to the second embodiment are the same as those in the first embodiment.

[0085] In step S41, similar to step S27 in the first embodiment, the bonding unit control unit 80 determines whether the detection process for all of the upper alignment marks AM1 arranged on the first substrate W1 has been completed. If the determination in step S41 is No, the process returns to step S21.

[0086] If the answer is Yes in step S41 (if the detection process for all of the upper alignment marks AM1 has been completed), in step S42, the joining unit control unit 80 determines whether the number N of the upper alignment marks AM1 imaged and detected by the lower-side wide-field alignment mark imaging unit 711b is equal to or greater than a predetermined number Nth, or whether the proportion R of the upper alignment marks AM1 imaged and detected by the lower-side wide-field alignment mark imaging unit 711b to all of the upper alignment marks AM1 for which the detection process has been performed is equal to or greater than a predetermined proportion Rth. The joining unit control unit 80 executes at least one of the determination of whether the number N is equal to or greater than the predetermined number Nth or the determination of whether the proportion R is equal to or greater than a predetermined proportion Rth. If the number N of the upper alignment marks AM1 imaged by the lower-side wide-field alignment mark imaging unit 711b is equal to or greater than the predetermined number Nth or the proportion R is equal to or greater than the predetermined proportion Rth (hereinafter referred to as the first condition), this means that the accuracy of the estimated position of the upper alignment mark AM1 is high. Furthermore, if the number N of upper alignment marks AM1 imaged by the lower wide-field alignment mark imaging unit 711b is less than a predetermined number Nth or the ratio R is less than a predetermined ratio Rth (hereinafter referred to as the second condition), it means that the accuracy of the estimated position of the upper alignment mark AM1 is low.

[0087] If the answer is No in step S42 (if the second condition is met), in step S43, the bonding unit control unit 80 executes error processing, similar to step S25 in the first embodiment. Specifically, the bonding unit control unit 80 stops the substrate bonding apparatus 1.

[0088] If the answer is Yes in step S42 (if the first condition is met), the process proceeds to step S44, where the upper reference mark MA1 arranged on the upper stage 51 is imaged by the lower alignment mark imaging unit 71b, and the position (coordinates) of the upper reference mark MA1 is detected, as in step S28 of the first embodiment. Thereafter, the process proceeds to step S3 shown in FIG.

[0089] [Effects of the second embodiment] In the second embodiment, the following effects can be obtained.

[0090] In the second embodiment, under the first condition, a relatively large number of alignment marks (AM1, AM2) are imaged by the alignment mark imaging units (711a, 711b) (the number N or proportion R of the alignment marks (AM1, AM2) that were estimated but not detected is relatively small), and therefore the positional deviation of the substrate W is relatively small. In this case, the alignment process can be appropriately performed based on the estimated positions of the alignment marks (AM1, AM2). Therefore, under the first condition, the alignment process is performed based on the estimated positions of the alignment marks (AM1, AM2). On the other hand, under the second condition, a relatively small number of alignment marks (AM1, AM2) are imaged by the alignment mark imaging units (711a, 711b), and therefore the positional deviation of the substrate W is relatively large. In this case, the alignment process cannot be appropriately performed based on the estimated positions of the alignment marks (AM1, AM2). Therefore, under the second condition, the error process is performed to prevent the inappropriate alignment process from being performed.

[0091] [Third embodiment] The alignment mark / reference mark detection process according to the third embodiment will be described with reference to Figures 27 and 28. Unlike the first embodiment in which alignment processing was performed based on the estimated positions of the alignment marks (AM1, AM2), the third embodiment images the alignment marks (AM1, AM2) using high-precision narrow-field alignment mark imaging units (712a, 712b) with a higher imaging magnification than the wide-field alignment mark imaging units (711a, 711b) based on the estimated positions of the alignment marks (AM1, AM2), and then performs alignment processing based on the imaged alignment marks (AM1, AM2).

[0092] (Alignment mark / reference mark detection process) 27, steps S11 to S13 and step S16 of the alignment mark / reference mark detection process according to the third embodiment are the same as those of the first embodiment. In step S16, as in the first embodiment, the bonding unit control unit 80 causes the upper-side narrow-field alignment mark imaging unit 712a to image the lower alignment mark AM2 based on the rough position of the lower alignment mark AM2 detected from the image captured by the upper-side wide-field alignment mark imaging unit 711a, and detects the position of the lower alignment mark AM2 with high accuracy. In the third embodiment, in step S51, the joining unit control unit 80 uses the XY stage 62 to change the relative position of the lower alignment mark AM2 and the upper narrow-field alignment mark imaging unit 712a based on the position of the lower alignment mark AM2 estimated in step S13 so that the lower alignment mark AM2 falls within the imaging range of the upper narrow-field alignment mark imaging unit 712a, which has a higher imaging magnification than the upper wide-field alignment mark imaging unit 711a. The joining unit control unit 80 then causes the upper narrow-field alignment mark imaging unit 712a to image the lower alignment mark AM2. Subsequent steps S17 and S18 are similar to those of the first embodiment. The upper narrow-field alignment mark imaging unit 712a is an example of the "alignment mark high-magnification imaging unit" in the claims.

[0093] After imaging and detection of the lower reference mark MA2 in step S18 of Fig. 27, the operations from step S21 onwards in Fig. 28 are performed. Specifically, as shown in Fig. 28, steps S21 to S23 and step S26 of the alignment mark / reference mark detection process according to the third embodiment are the same as those in the first embodiment. In step S26, the bonding unit control unit 80 causes the lower narrow-field alignment mark imaging unit 712b to image the upper alignment mark AM1 based on the rough position of the upper alignment mark AM1 detected from the image captured by the lower wide-field alignment mark imaging unit 711b, and detects the position of the upper alignment mark AM1 with high accuracy. In the third embodiment, in step S52, the joining unit control unit 80 changes the relative positions of the upper alignment mark AM1 and the lower narrow-field alignment mark imaging unit 712b using the XY stage 62 based on the position of the upper alignment mark AM1 estimated in step S23 so that the upper alignment mark AM1 falls within the imaging range of the lower narrow-field alignment mark imaging unit 712b, which has a higher imaging magnification than the lower wide-field alignment mark imaging unit 711b. The joining unit control unit 80 then causes the lower narrow-field alignment mark imaging unit 712b to image the upper alignment mark AM1. Thereafter, alignment processing is performed. Subsequent steps S27 and S28 are similar to those of the first embodiment. The lower narrow-field alignment mark imaging unit 712b is an example of the "alignment mark high-magnification imaging unit" in the claims.

[0094] [Effects of the third embodiment] In the third embodiment, the following effects can be obtained.

[0095] In the third embodiment, as described above, the joining unit control unit 80 performs alignment processing by causing the narrow-field alignment mark imaging units (712a, 712b) to capture images of the alignment marks (AM1, AM2). This allows the alignment marks (AM1, AM2) to be captured with greater precision by the narrow-field alignment mark imaging units (712a, 712b) with a high imaging magnification, and therefore allows more accurate alignment processing to be performed based on the more accurately captured images of the alignment marks (AM1, AM2).

[0096] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0097] In the first embodiment, the joining unit control unit 80 may be configured to include only the wide-field alignment mark imaging units (711a, 711b) and not the narrow-field alignment mark imaging units (712a, 712b). That is, if the lower alignment mark AM2 is detected in step S12, the joining unit control unit 80 may detect the position of the lower alignment mark AM2 from the image captured by the upper wide-field alignment mark imaging unit 711a in step S16. If the upper alignment mark AM1 is detected in the image captured by the lower wide-field alignment mark imaging unit 711b in step S22, the joining unit control unit 80 may detect the position of the upper alignment mark AM1 from the image captured by the lower wide-field alignment mark imaging unit 711b in step S26.

[0098] In the first to third embodiments described above, the joining unit control unit 80 estimates the positions of the lower alignment mark AM2 and the upper alignment mark AM1 in both cases where the lower alignment mark AM2 cannot be detected in the image captured by the upper wide-field alignment mark imaging unit 711a and where the upper alignment mark AM1 cannot be detected in the image captured by the lower wide-field alignment mark imaging unit 711b. However, the present invention is not limited to this. For example, the position of the lower alignment mark AM2 or the upper alignment mark AM1 may be estimated in only one of cases where the lower alignment mark AM2 cannot be detected in the image captured by the upper wide-field alignment mark imaging unit 711a and where the upper alignment mark AM1 cannot be detected in the image captured by the lower wide-field alignment mark imaging unit 711b.

[0099] In the above first to third embodiments, the bonding unit control unit 80 has shown an example in which the alignment process is performed in a state in which the coordinate system of the upper alignment mark AM1 (coordinate system 1) and the coordinate system of the lower alignment mark AM2 (coordinate system 2) are aligned with the coordinate system of the lower stage 61 (coordinate system 3), which is a common reference coordinate system, but the present invention is not limited to this. For example, the alignment process may be performed in a state in which the coordinate system 1 and the coordinate system 2 are aligned with a common reference coordinate system other than the coordinate system of the lower stage 61.

[0100] In the first to third embodiments described above, the bonding unit control unit 80 performs alignment processing based on the estimated positions of the alignment marks (AM1, AM2) when the first condition is met in which the accuracy of the estimated positions of the alignment marks (AM1, AM2) is high, and performs error processing when the second condition is met in which the accuracy of the estimated positions of the alignment marks (AM1, AM2) is low. However, the present invention is not limited to this. For example, if it is guaranteed that the accuracy of the estimated positions of the alignment marks (AM1, AM2) is high, the bonding unit control unit 80 may always perform alignment processing based on the estimated positions of the alignment marks (AM1, AM2) without performing error processing.

[0101] In the first to third embodiments, an example was shown in which, in the case of the second condition where the accuracy of the estimated positions of the alignment marks (AM1, AM2) is low, the substrate bonding apparatus 1 is stopped as an error processing. However, the present invention is not limited to this. For example, in the case of the second condition, the error processing may be performed by changing the relative position between the upper wide-field alignment mark imaging unit 711a and the lower alignment mark AM2 using the XY stage 62 based on the estimated positions of the alignment marks (AM1, AM2), and then causing the upper wide-field alignment mark imaging unit 711a to image the lower alignment mark AM2 again. Alternatively, the XY stage 62 may be used to change the relative position between the lower wide-field alignment mark imaging unit 711b and the upper alignment mark AM1, and then causing the lower wide-field alignment mark imaging unit 711b to image the upper alignment mark AM1 again. As a result, the alignment marks (AM1, AM2) are imaged by the alignment mark imaging units (711a, 711b), and alignment processing can be performed appropriately based on the imaged alignment marks (AM1, AM2). Furthermore, as a process of re-imaging the alignment marks (AM1, AM2), the alignment marks (AM1, AM2) may be imaged using the narrow-field alignment mark imaging units (712a, 712b) instead of the wide-field alignment mark imaging units (711a, 711b).

[0102] Furthermore, in the case of the second condition, as an error processing, a warning that the accuracy of the estimated positions of the alignment marks (AM1, AM2) is low may be displayed on the display unit 31a. For example, as in a first modified example shown in FIG. 29, a message stating "The accuracy of the estimated positions of the alignment marks is low" is displayed on the display unit 31a. In this case, the processing of the substrate bonding apparatus 1 continues, but information about the substrate W having the low accuracy of the positions of the alignment marks (AM1, AM2) is stored in the substrate bonding apparatus 1, and the user can check the information after the processing of the substrate bonding apparatus 1 is completed. In this way, as an error processing, a warning that the accuracy of the estimated positions of the alignment marks (AM1, AM2) is low may be displayed on the display unit 31a, thereby prompting the user to check the substrate W. Furthermore, in the case of the second condition, as an error processing, a substrate W having the low accuracy of the positions of the alignment marks (AM1, AM2) may be discharged from the bonding unit 5 without undergoing the bonding processing.

[0103] In the first to third embodiments, the storage unit 80a pre-stores information on the positional relationship between the peripheral pattern PT as information on the peripheral feature portion F and the alignment marks (AM1, AM2). However, the present invention is not limited to this. For example, as in the second modified example, the storage unit 80a may pre-store information on the positional relationship between a substrate shape portion relating to the shape of the substrate W and the alignment marks (AM1, AM2) as information on the peripheral feature portion F. Here, as shown in FIG. 30 , the substrate shape portion of the second modified example includes at least one of the edge E, notch N, and orientation flat O of the substrate W. The edge E of the substrate W is the outer edge of the substrate W and is a portion on a circular arc other than the orientation flat O. Because the edge E, notch N, and orientation flat O of the substrate W are shapes that the substrate W originally has, it is possible to omit the step of separately forming, on the substrate W, substrate shape portions that serve as markers for estimating the positions of the alignment marks (AM1, AM2). Furthermore, the bonding unit control unit 80 can easily estimate the positions of the alignment marks (AM1, AM2) by referring to information on the positional relationship between the substrate shape portion (peripheral feature portion F) and the alignment marks (AM1, AM2) that is stored in advance in the storage unit 80a. As a result, even if the alignment marks (AM1, AM2) arranged on the substrate W cannot be imaged, the pair of substrates W to be bonded can be aligned based on the positions of the alignment marks (AM1, AM2) estimated from the substrate shape portion (peripheral feature portion F) stored in the storage unit 80a. The edge E, notch N, and orientation flat O of the substrate W are examples of the "substrate shape portion" in the claims. [Explanation of symbols]

[0104] 1 Substrate bonding equipment 31a Display section 51 Upper Stage (Stage) 61 Lower Stage (Stage) 62 XY stage (moving mechanism) 80 Joining unit control section (control section) 80a storage section 711a Upper wide-field alignment mark imaging unit (alignment mark imaging unit, second alignment mark imaging unit) 712a Upper narrow-field alignment mark imaging unit (high-magnification alignment mark imaging unit) 711b Lower wide-field alignment mark imaging unit (alignment mark imaging unit, first alignment mark imaging unit) 712b Lower narrow-field alignment mark imaging unit (high-magnification alignment mark imaging unit) AM1 Upper alignment mark (first alignment mark) AM2 Lower alignment mark (second alignment mark) E (board) edge (board shape part) F. Peripheral features L11, L12 separation distance N Notch (substrate shape part) O Orientation flat (board shape part) P11, P21 center of visual field PT Peripheral Pattern W1 First board (board, upper board) W2 Second board (substrate, lower board)

Claims

1. a pair of stages each holding a pair of substrates to be bonded together; an alignment mark imaging unit that images at least one of the alignment marks disposed on the pair of substrates; a storage unit configured to store information on a peripheral feature portion including at least one of a peripheral pattern arranged around the alignment mark on the substrate and a substrate shape portion relating to the shape of the substrate; a moving mechanism that changes the relative position between the stage and the alignment mark imaging unit; a control unit that detects the alignment mark in the image captured by the alignment mark imaging unit, The control unit when the alignment mark cannot be detected in the image captured by the alignment mark imaging unit, estimating the position of the alignment mark based on the information of the peripheral characteristic part stored in the memory unit; The substrate bonding apparatus performs an alignment process for aligning the pair of substrates for bonding based on the estimated positions of the alignment marks.

2. the pair of substrates includes a first substrate and a second substrate, the alignment marks include a first alignment mark disposed on the first substrate and a second alignment mark disposed on the second substrate; the alignment mark imaging unit includes a first alignment mark imaging unit that images the first alignment mark and a second alignment mark imaging unit that images the second alignment mark; 2. The substrate bonding apparatus of claim 1, wherein the control unit, in at least one of the cases where the first alignment mark cannot be detected in the image captured by the first alignment mark imaging unit and where the second alignment mark cannot be detected in the image captured by the second alignment mark imaging unit, estimates the position of at least one of the first alignment mark and the second alignment mark based on information about the surrounding feature portion stored in the memory unit, and performs an alignment process to align the first substrate and the second substrate for bonding.

3. The substrate bonding apparatus of claim 2, wherein the control unit performs the alignment process in a state in which the coordinate systems of the first alignment mark or the estimated first alignment mark imaged by the first alignment mark imaging unit and the second alignment mark or the estimated second alignment mark imaged by the second alignment mark imaging unit are aligned to a common reference coordinate system.

4. The control unit In the case of a first condition in which the accuracy of the estimated alignment mark position is high, the alignment process is performed based on the estimated alignment mark position; 2. The substrate bonding apparatus according to claim 1, wherein error processing is performed when a second condition is met in which the accuracy of the estimated alignment mark position is low.

5. the first condition is that a distance between the estimated position of the alignment mark and the center of a field of view of the alignment mark imaging unit is equal to or less than a predetermined distance; The substrate bonding apparatus according to claim 4 , wherein the second condition is that the separation distance is greater than the predetermined distance.

6. a plurality of the alignment marks are arranged on the substrate; the first condition is that the number of the alignment marks imaged and detected by the alignment mark imaging unit is equal to or greater than a predetermined number, or the proportion of the alignment marks imaged and detected by the alignment mark imaging unit is equal to or greater than a predetermined proportion, The substrate bonding apparatus according to claim 4 , wherein the second condition is that the number is less than the predetermined number or the ratio is less than the predetermined ratio.

7. 5. The substrate bonding apparatus of claim 4, wherein the error processing includes any one of the following: changing the relative position between the alignment mark imaging unit and the alignment mark using the moving mechanism based on the estimated alignment mark position, and then performing a process of imaging the alignment mark using the alignment mark imaging unit again; stopping the substrate bonding apparatus; and displaying a warning on a display unit that the accuracy of the estimated alignment mark position is low.

8. 2. The substrate bonding apparatus according to claim 1, wherein the peripheral pattern is formed with the same positional accuracy as that of the alignment mark.

9. further comprising an alignment mark high-magnification imaging unit having an imaging magnification higher than that of the alignment mark imaging unit, 2. The substrate bonding apparatus of claim 1, wherein the control unit uses the moving mechanism to change the relative position of the alignment mark and the alignment mark high-magnification imaging unit so that the alignment mark is within the imaging range of the alignment mark high-magnification imaging unit based on the estimated position of the alignment mark, and causes the alignment mark high-magnification imaging unit to capture an image of the alignment mark, thereby performing the alignment process.

10. The substrate bonding apparatus according to claim 1 , wherein the memory unit pre-stores information on the positional relationship between the alignment mark and at least one of the peripheral pattern and the substrate shape portion included in the information on the peripheral feature portion.

11. The substrate bonding apparatus of claim 1 , wherein the substrate shape portion includes at least one of an edge, a notch, and an orientation flat of the substrate.

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