Multi-axis stage apparatus, wafer bonding method using the same, and wafer bonding apparatus

Abstract

The present invention provides a multi-axis stage apparatus, a wafer bonding method using the same, and a wafer bonding apparatus that can significantly improve the accuracy of wafer bonding. [Solution] The multi-axis stage device 100 includes a base portion B, an alignment stage 30 for aligning a first wafer chuck C1 that has a first wafer chucked in it, a first drive device 10 formed between the base portion and the alignment stage for raising and lowering the alignment stage with low precision, and a second drive device 20 formed between the base portion and the alignment stage for raising and lowering the alignment stage with high precision. The second drive device has a flexible hinge portion 224 formed in at least a part of it that distributes the load.

Description

Technical Field

[0001] The present invention relates to a multi-axis stage device, a wafer bonding method and a wafer bonding device using the same. More specifically, the present invention relates to a multi-axis stage device capable of greatly improving the accuracy of wafer bonding, a wafer bonding method using the same, and a wafer bonding device.

Background Art

[0002] The semiconductor manufacturing process is a process for manufacturing semiconductor elements on a substrate (e.g., a wafer), and can include, for example, exposure, deposition, etching, ion implantation, cleaning, and the like.

[0003] In order to perform each manufacturing process, semiconductor manufacturing equipment for performing each process is provided in a clean room of a semiconductor manufacturing factory, and process processing on a substrate input to the semiconductor manufacturing equipment can be performed.

[0004] On the other hand, in order to produce a semiconductor product in a form in which a plurality of substrates are stacked, such as HBM (High Bandwidth Memory), a wafer-to-wafer (W2W) bonding process for bonding wafers to each other has been developed. Such a conventional wafer bonding process is a process of bonding a large number of wafers to each other, and can include, roughly, a process of aligning the wafers with each other and a process of bringing the wafers into close contact with each other.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in order to ensure a sufficient stroke, a conventional wafer bonding device uses, for example, a single driving device with an accuracy in micrometers or millimeters to raise and lower a wafer in the Z-axis direction. Therefore, it is very difficult mechanically to ensure a high accuracy in nanometers. Even if the accuracy of a single driving device is increased, there are many problems such as a very slow raising and lowering speed.

[0006] Furthermore, conventional wafer bonding equipment uses ball joints and other components for multi-axis movement and rotation of the wafer chuck, such as the X, Y, Z, first rotation axis, second rotation axis, and theta axis (third rotation axis). This makes it prone to mechanical errors and component damage, and also leads to mechanical and thermal deformation under load, among other problems.

[0007] The present invention aims to solve various problems, including those described above, and provides a multi-axis stage apparatus, a wafer bonding method, and a wafer bonding apparatus using the same, which can greatly improve the accuracy of wafer bonding by using two drive devices with different accuracies for the vertical movement of the Z axis. However, these problems are illustrative and do not limit the scope of the present invention. [Means for solving the problem]

[0008] A multi-axis stage apparatus according to the concept of the present invention for solving the above problems includes a base portion, an alignment stage for aligning a first wafer chuck that has a first wafer chucked in it, a first drive device formed between the base portion and the alignment stage for raising and lowering the alignment stage with low precision, and a second drive device formed between the base portion and the alignment stage for raising and lowering the alignment stage with high precision, wherein the second drive device may have a flexible hinge portion formed in at least a part of it for distributing the load.

[0009] On the other hand, a wafer bonding method using a multi-axis stage apparatus according to the concept of the present invention for solving the above problems includes the steps of: (a) when a second wafer transfer arm transfers the second wafer below the second wafer chuck, the picker of the second wafer chuck picks up the second wafer and brings the second wafer into close contact with the second wafer chuck, and the second wafer chuck chucking the attached second wafer; (b) confirming the position of the second wafer using a first camera formed on the first wafer chuck or the alignment stage; and (c) roughly raising and lowering the first wafer chuck with low precision using a first drive device, and The procedure may include: (d) a first wafer transfer arm loading the first wafer onto the lift pin of the first wafer chuck and lowering the lift pin so that the first wafer chuck chucking the first wafer; (e) a second camera and alignment stage formed on the second wafer chuck, which are used to precisely align the first wafer in the first axial direction, the second axial direction, and theta axial direction with reference to the second wafer whose position has been confirmed; and (f) a second drive device having a flexible hinge, which is used to precisely raise and lower the first wafer chuck with high precision and to bond the aligned first wafer and the second wafer.

[0010] On the other hand, a wafer bonding apparatus according to the concept of the present invention for solving the above problems includes a base portion, an alignment stage for aligning a first wafer chuck that has a first wafer chucked in it, a first drive device formed between the base portion and the alignment stage for raising and lowering the alignment stage with low precision, and a second drive device formed between the base portion and the alignment stage for raising and lowering the alignment stage with high precision, wherein the second drive device has a flexible hinge portion formed in at least a part for distributing the load, and the second drive device has a plurality of first voice coil motors (VCMs) arranged at equiangled angles around the central axis of lifting and lowering.A voice coil motor, a movable base having a flexible hinge portion which is partly fixed and the other part which can be raised and lowered relatively with high precision by the first voice coil motor, and a flexure joint (Flexure) formed on the movable base which has multiple degrees of freedom The movable stage includes an inner column formed vertically overall so that the load can be distributed along a first path; an outer column formed vertically overall so that the load can be distributed along a second path and is formed outward from the inner column; a precision lifting section formed between the inner column and the outer column so that the load can be distributed along a third path and is raised and lowered with high precision by the first voice coil motor; and flexible hinge sections formed between the inner column and the precision lifting section, and between the outer column and the precision lifting section, respectively, so as to elastically support the precision lifting section, wherein the first drive unit can raise and lower at least a portion of the base unit by a first distance in the third axial direction, and the second drive unit can raise and lower at least a portion of the first drive unit by a second distance in the third axial direction, and the alignment stage is positioned such that the first wafer is in front of The alignment stage is connected to a second drive unit so that it can be raised and lowered in the third axis direction by a distance equal to the sum of the first distance and the second distance. The first drive unit can roughly raise and lower the first wafer by a first distance that is relatively longer than the second distance with low precision, and the second drive unit can precisely raise and lower the first wafer by a second distance that is relatively shorter than the first distance. The alignment stage aligns the first wafer in the first axis direction, the second axis direction, and the theta axis direction using a second voice coil motor or a piezo element. The alignment stage may include a stage jig, a flexure frame in which part is fixed to the stage jig and the other part is elastically deformed with respect to the stage jig, and at least one second voice coil motor formed on the stage jig and elastically deforms the other part of the flexure frame. [Effects of the Invention]

[0011] According to the various embodiments of the present invention described above, by using multiple first drive units, which have low precision but a long stroke, and second drive units, which have a short stroke but high precision, in combination for the Z-axis lifting motion, the accuracy and process speed of wafer bonding can be greatly improved. By using a voice coil motor and a flexure joint, mechanical errors and component damage during multi-axis drive can be prevented. By distributing the load across multiple paths, mechanical and thermal deformation of components due to the load can be prevented, resulting in a significant improvement in product productivity, durability, and reliability. Of course, the scope of the present invention is not limited by these effects. [Brief explanation of the drawing]

[0012] [Figure 1] This is a conceptual side cross-sectional view showing a multi-axis stage device according to some embodiments of the present invention. [Figure 2] Figure 1 is an exploded perspective view showing the multi-axis stage device. [Figure 3] Figure 2 is a perspective view showing the alignment stage of a multi-axis stage apparatus. [Figure 4] Figure 3 is a plan view showing the alignment stage of the multi-axis stage device. [Figure 5] Figure 2 is a perspective view showing the second drive unit of the multi-axis stage device. [Figure 6] Figure 5 is a perspective view showing the movable platform of the second drive unit. [Figure 7] Figure 5 is a perspective view showing the flexure joint of the second drive unit. [Figure 8] Figure 2 is a perspective view showing the first drive unit of the multi-axis stage device. [Figure 9] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 10] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 11] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 12] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 13] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 14] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 15] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 16] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 17] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 18] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 19] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 20] It is a cross-sectional view showing step by step the wafer bonding process using the multi-axis stage device of FIG. 1. [Figure 21] It is a flowchart showing a wafer bonding method using a multi-axis stage device according to some embodiments of the present invention.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0014] The embodiments of the present invention are provided to further and completely illustrate the invention to those who are ordinary skill in the art, and the embodiments described below can be modified in various other forms, and the scope of the invention is not limited to the embodiments described below. Rather, these embodiments are provided to further enrich and complete the disclosure and to fully convey the idea of ​​the invention to those skilled in the art. Also, the thickness and size of each layer in the drawings are exaggerated for the sake of clarity and ease of explanation.

[0015] The terms used herein are used to describe specific embodiments and are not intended to limit the invention. As used herein, a singular form can include multiple forms unless the context explicitly indicates otherwise. Also, as used herein, “comprise” and / or “comprising” identify the presence of the shapes, figures, stages, actions, members, elements and / or groups thereof mentioned, and do not exclude the presence or addition of one or more other shapes, figures, actions, members, elements and / or groups thereof.

[0016] Hereinafter, embodiments of the present invention will be described with reference to drawings schematically illustrating ideal embodiments of the present invention. In the drawings, deformation of the illustrated shapes may be expected, for example, due to manufacturing techniques and / or tolerances. Therefore, embodiments of the concept of the present invention should not be construed as being limited to specific shapes in the region shown herein, and should include, for example, shapes that may be induced during manufacturing.

[0017] Figure 1 is a side cross-sectional view showing a multi-axis stage device 100 according to several embodiments of the present invention, and Figure 2 is an exploded perspective view showing the multi-axis stage device 100 of Figure 1.

[0018] First, as shown in Figures 1 and 2, the multi-axis stage apparatus 100 according to some embodiments of the present invention can be broadly classified into a base unit B, a first drive unit 10, a second drive unit 20, and an alignment stage 30.

[0019] The base portion B is a support structure that, for example, supports the first drive unit 10, the second drive unit 20, and the alignment stage 30, and has sufficient strength and durability to withstand wafer bonding pressure. It is not necessarily limited to the drawings, and a wide variety of three-dimensional structures of different types and shapes are applicable.

[0020] The first drive unit 10 may be a type of primary lifting drive unit that is formed, for example, on the base unit B or between the base unit B and the alignment stage 30, and can roughly raise and lower at least a portion of it by a first distance L1 (see Figure 16) in the third axis direction III with relatively low precision, relative to the base unit B.

[0021] Here, the third axis direction III is a direction perpendicular to the plane (horizontal plane) that spans the first axis direction I and the second axis direction II. For example, the third axis direction III could be the Z-axis direction, which is the direction in which the first wafer W1 moves up and down. The second axis direction II could be the Y-axis direction, which is the main direction in which the first wafer W1 is loaded or unloaded, and the first axis direction I could be the X-axis direction, which is perpendicular to the second axis direction II. However, such first axis direction I, second axis direction II, and third axis direction III are not necessarily limited to those shown in the drawing, and all directions perpendicular to each other are applicable.

[0022] The second drive unit 20 is, for example, formed on the first drive unit 10 or between the base unit B and the alignment stage 30, and can be a type of secondary lifting drive unit that can raise and lower at least a portion of it with relative high precision by a second distance L2 (see Figure 20) in the third axis direction III with reference to the first drive unit 10.

[0023] Here, the first drive unit 10 is capable of roughly raising and lowering the first wafer W1 by a first distance L1 that is relatively longer than the second distance L2, and can be a relatively low-precision lifting drive system that can raise and lower the first wafer W1 with a low precision of approximately micrometers or millimeters or more, for example, by using a ball screw or a lead screw.

[0024] Furthermore, the second drive unit 20 is capable of precisely raising and lowering the first wafer W1 by a second distance L2 that is relatively shorter than the first distance L1, and can be a relatively high-precision lifting drive system that can raise and lower the first wafer W1 with high precision of approximately nanometer units or less, for example, by using a first voice coil motor (VCM) or a piezoelectric element.

[0025] Here, the second drive unit 20 may have a flexible hinge part 224 that distributes the load to at least a portion of it.

[0026] For the sake of mechanical explanation, for example, the drawings show the second drive unit 20 connected above the first drive unit 10, but it is also possible for the first drive unit 10 to be connected above the second drive unit 20.

[0027] The alignment stage 30 is connected to the second drive unit 20 so that the first wafer W1 can move up and down in the third axis direction III by a distance equal to the sum of the first distance L1 and the second distance L2, and can be a type of alignment device for aligning the first wafer chuck C1 that holds the first wafer W1. Here, the first wafer chuck C1 can be either a vacuum chuck or an electrostatic chuck.

[0028] Such an alignment stage 30 can align the first wafer W1 in the first axis direction I, the second axis direction II, and theta axis direction R3, for example, using a second voice coil motor 33 (see Figure 3) or a piezoelectric element.

[0029] Here, the theta axis direction R3 can be the direction of rotation around the third axis direction III as the axis of rotation in a plane consisting of the first axis direction I and the second axis direction II. However, it is not necessarily limited to the drawing, and a variety of rotation directions are all applicable.

[0030] To give a more specific example, as shown in Figures 1 and 2, the first drive device 10 may include a drive motor 11 formed on the base portion B that rotates the threaded rod S, and a movable frame 12 on which a nut member N is formed, whose lifting path is guided by a rail member R formed on the base portion B and which moves up and down as the threaded rod S rotates.

[0031] The second drive unit 20 may include, for example, a plurality (four in the drawings) of first voice coil motors 21 (VCMs) arranged at equiangled angles around a nut member N on a lifting central axis or movable frame 12, as shown in Figures 1 and 2; a movable base 22 having a flexible hinge portion 224, one part of which is relatively fixed and the other part which can be raised and lowered relatively with high precision by the first voice coil motors 21; and a flexure joint 23 formed on the movable base 22 and having multiple degrees of freedom.

[0032] Here, the first voice coil motors 21 can be arranged at equal angles around the nut member N on the movable frame 12, so that the first wafer W1 can rotate in the first rotation axis direction R1 or the second rotation axis direction R2, thereby reducing the product capacity and installation costs, while simultaneously increasing the number of motors to distribute the load. However, such first voice coil motors 21 are not limited to a quadrangular arrangement; for example, a wide variety of numbers, such as a triangular, pentagonal, or hexagonal arrangement, can be arranged at equal angles around the nut member N on the movable frame 12.

[0033] Here, the first rotation axis direction R1 can be the direction of rotation around the first rotation axis I in a plane consisting of the second rotation axis II and the third rotation axis III, and the second rotation axis direction R2 can be the direction of rotation around the second rotation axis II in a plane consisting of the first rotation axis I and the third rotation axis III. However, the first rotation axis direction R1 and the second rotation axis direction R2 are not necessarily limited to those shown in the drawing, and a variety of rotation directions are all applicable.

[0034] Here, a voice coil motor (VCM) is a type of linear motor that uses the principle of a speaker and can be a motor device that induces very precise linear motion in proportion to the current flowing through a coil in the magnetic field of a permanent magnet.

[0035] However, the second drive device 20 of the present invention can be used with a wide variety of precision motors, such as a piezo motor using a piezo element, instead of the first voice coil motor 21.

[0036] Furthermore, unlike ball joints, the Flexure Joint 23 is a joint that uses leaf springs, coil springs, and other complex three-dimensional spring hinges, and can sufficiently absorb elastic deformation, thereby preventing mechanical errors and component damage.

[0037] Therefore, by using multiple first voice coil motors 21, for example, if all first voice coil motors 21 are extended or retracted uniformly, the alignment stage 30 can be raised and lowered with great precision in the third axis direction III, and if at least one of the first voice coil motors 21 is extended or retracted differently, the alignment stage 30 can be rotated at an inclination in the first rotation axis direction R1 or the second rotation axis direction R2.

[0038] Figure 3 is a perspective view showing the alignment stage 30 of the multi-axis stage device 100 in Figure 2, and Figure 4 is a plan view showing the alignment stage of the multi-axis stage device in Figure 3.

[0039] As shown in Figures 1 to 4, the alignment stage 30 of the multi-axis stage device 100 according to some embodiments of the present invention can be installed, for example, between the base portion B, the first drive unit 10, and the second drive unit 20, or on the second drive unit 20, and may include a stage jig 31, a flexure frame 32 in which part is fixed to the stage jig 31 and the other part is elastically deformed with respect to the stage jig 31, and at least one second voice coil motor 33 formed on the stage jig 31 and causing the other part of the flexure frame 32 to elastically deform.

[0040] To give a more specific example, the flexure frame 32 may include a fixed portion 321 that is fixed to the stage jig 31, a flexible hinge 322 made of an elastic material formed on the fixed portion 321, and a movable portion 323 that supports the first wafer chuck C1 and is precisely elastically displaced using the flexible hinge 322.

[0041] For example, the flexible hinge 322 may include, as shown in Figure 4, at least one first hinge H1 which is generally elongated in the first axial direction I and elastically deforms in the second axial direction II, at least one second hinge H2 which is generally elongated in the second axial direction II and elastically deforms in the first axial direction I, and at least one rotary hinge H3 formed on the movable part 323 so that the movable part 323 can rotate in the theta axis direction.

[0042] Therefore, when using the first hinge H1, second hinge H2, and rotary hinge H3 of such a flexible hinge 322, the movement in the first axial direction I, the second axial direction II, and the theta axial direction R3 can be guided very precisely and elastically according to the amount of power applied to each of the second voice coil motors 33.

[0043] Furthermore, for example, the second voice coil motor 33 may include, for example, a total of four voice coil motors, and may include: a first-axis positive voice coil motor 331 formed on one side of the movable part 323 and oriented in the positive direction of the first axis I; a first-axis reverse voice coil motor 332 formed on the other side of the movable part 323 and oriented in the opposite direction of the first axis I so that the movable part 323 can move precisely in the first axis I or rotate precisely in the theta axis R3; a second-axis positive voice coil motor 333 formed on yet another side of the movable part 323 and oriented in the positive direction of the second axis II; and a second-axis reverse voice coil motor 334 formed on yet another side of the movable part 323 and oriented in the opposite direction of the second axis II so that the movable part 323 can move precisely in the second axis II or rotate precisely in the theta axis R3.

[0044] Therefore, for example, if the first-axis positive-direction voice coil motor 331 of the four second-axis voice coil motors 33 installed on the stage jig 31 is extended while the first-axis reverse-direction voice coil motor 332 is retracted, the movable part 323 can be precisely moved in the first-axis direction I. If the first-axis positive-direction voice coil motor 331 is extended while the first-axis reverse-direction voice coil motor 332 is also extended, the movable part 323 can be precisely rotated in the theta axis direction R3. When using the second-axis positive-direction voice coil motor 333 and the second-axis reverse-direction voice coil motor 334 using this principle, the movable part 323 can be precisely moved in the second-axis direction II or precisely rotated in the theta axis direction R3.

[0045] Figure 5 is a perspective view showing the second drive unit 20 of the multi-axis stage device 100 in Figure 2, Figure 6 is a perspective view showing the movable base 22 of the second drive unit 20 in Figure 5, and Figure 7 is a perspective view showing the flexure joint 23 of the second drive unit 20 in Figure 5.

[0046] As shown in Figures 5 to 7, the second drive unit 20 of the multi-axis stage device 100 according to some embodiments of the present invention may include, for example, four first voice coil motors 21 arranged at equiangled angles around a nut member N on a movable frame 12, a movable table 22 having a flexible hinge portion 224 that is partly fixed relative to the first voice coil motors 21 and the other part can be raised and lowered relatively with high precision by the first voice coil motors 21, and a flexure joint 23 formed on the movable table 22 having multiple degrees of freedom.

[0047] The movable platform 22 may include, for example, an inner column portion 221 formed vertically overall so that the load can be distributed along a first path P1 (see Figure 1), as shown in Figure 6; an outer column portion 222 formed vertically overall so that the load can be distributed along a second path P2 (see Figure 1) and formed outward from the inner column portion 221; a precision lifting section 223 formed between the inner column portion 221 and the outer column portion 222 so that the load can be distributed along a third path P3 (see Figure 1), and which is raised and lowered with high precision by a first voice coil motor 21; and flexible hinge portions 224 formed between the inner column portion 221 and the precision lifting section 223, and between the outer column portion 222 and the precision lifting section 223, respectively, so as to elastically support the precision lifting section 223.

[0048] Here, for example, the inner column section 221 and the outer column section 222 are fixed relative to the movable frame 12 (see Figure 1) described above, and the precision lifting section 223 can be raised and lowered elastically with high precision by the first voice coil motor 21.

[0049] To give a more specific example, the flexible hinge portion 224 is a type of double hinge structure that elastically supports the precision lifting portion 223 so that the precision lifting portion 223 can move up and down with high precision and very precision, and may include an upper bridge portion 224a formed on the upper part of the precision lifting portion 223, and a lower bridge portion 224b formed parallel to the upper bridge portion 224a at a distance D from the upper bridge portion 224a and formed in the middle or lower part of the precision lifting portion 223 so that the precision lifting portion 223 can move up and down vertically as a whole.

[0050] Therefore, by using such a double-hinge flexible hinge section 224, the precision lifting section 223 can be raised and lowered vertically with high precision and accuracy. At the same time, as shown in Figure 1, loads such as the weight of the device itself and press pressure from above can be distributed to multiple paths, the first path P1, the second path P2, and the third path P3, thereby improving the durability of the components against external forces and preventing damage to the components due to impact. This also significantly reduces a portion of the load transmitted to the first voice coil motor 21, thereby minimizing the heat generated by the first voice coil motor 21 due to the load.

[0051] The flexure joint 23 may include, for example, a joint fixing portion 23a fixed to the movable base 22 relative to the joint fixing portion 23a, a joint movable portion 23b that can move elastically relative to the joint fixing portion 23a, and a joint flexible hinge 23c formed between them, as shown in Figure 7.

[0052] Here, the joint fixing part 23a, the joint movable part 23b, and the joint flexible hinge 23c are not necessarily limited to those shown in the drawings, and a wide variety of three-dimensional structures are applicable.

[0053] Figure 8 is a perspective view showing the first drive unit 10 of the multi-axis stage device 100 shown in Figure 2.

[0054] The first drive unit 10 may include, for example, a drive motor 11 formed on the base portion B for rotating the threaded rod S, and a movable frame 12 whose lifting path is guided by a rail member R formed on the base portion B, and which has a nut member N formed in its center that moves up and down by the rotation of the threaded rod S.

[0055] Here, the drive motor 11 may be a DD motor (Direct Drive Motor) that directly drives the threaded rod S without a separate power transmission device or actuator, for example, in order to improve accuracy. In addition, the drive motor 11 can be any of the many different types of motors, including a servo motor.

[0056] Furthermore, the movable frame 12 may be made of a disc or polygonal plate shape with a threaded rod S and a screwed nut member N formed in the central part, so that the center of gravity can be applied uniformly.

[0057] Furthermore, the threaded rod S can be rotatably supported by support bases 13 and 14 formed on the base portion B, and such support bases can be attached to the base portion B with screws or bolts so as to facilitate the assembly of the parts.

[0058] Therefore, according to the first drive device 10, when the drive motor 11 rotates the threaded rod S in the forward or reverse direction, the nut member N screwed to the threaded rod S moves vertically up and down, thereby causing the movable frame 12 to move up and down. If necessary, the moving frame 12 can be guided along its up and down path by a rail member R such as a linear motion guide (LMG) formed on the base portion B.

[0059] Figures 9 to 20 are cross-sectional views showing the wafer bonding process using the multi-axis stage apparatus shown in Figure 1, step by step.

[0060] As shown in Figures 1 and 9, some embodiments of the present invention may further include a transfer device 40 that moves the base portion B back and forth to a position corresponding to the second wafer chuck C2 in which the second wafer W2 is chucked, so that the second wafer W2 can be bonded to the first wafer W1.

[0061] Furthermore, some embodiments of the present invention may further include a multi-axis stage apparatus 100 which is formed on a first wafer chuck C1 or an alignment stage 30 and photographs a second identifier M2 of a second wafer W2; a measuring device 50 such as an encoder for measuring the lifting distance of the first wafer W1 or the first wafer chuck C1; and a control unit 60 which receives a video signal from the first camera CA1 or a measurement signal from the measuring device 50 and applies a control signal to at least one of the first drive unit 10, the second drive unit 20, the alignment stage 30, the transfer device 40, and any combination thereof.

[0062] Here, the measuring device 50 can use various encoders and sensors that convert the position and distance of an object into electrical signals and output them. For example, a linear encoder capable of checking an angle range of 0.5° may be used.

[0063] Furthermore, the control unit 60 can, for example, apply a primary lifting control signal to the first drive unit 10 in the first wafer loading mode, in which the first wafer W1 is loaded into the first wafer chuck C1 and the first wafer chuck C1 chucking the first wafer W1; apply an alignment control signal to the alignment stage 30 in which the first wafer W1 is precisely aligned in the first axis direction I, the second axis direction II, and theta axis direction R3 with respect to the second wafer W2 whose position has been confirmed; and apply a secondary lifting control signal to the second drive unit 20 in the bonding mode, in which the aligned first wafer W1 and second wafer W2 are bonded. Various control devices such as microprocessors, central processing units, arithmetic units, signal input / output devices, storage devices for storing programs, personal computers, server computers, networks, smartphones, smart pads, smart devices, control boards, control chips, control components, and electronic components are all applicable.

[0064] On the other hand, as shown in Figure 9, a wafer bonding apparatus 1000 having a multi-axis stage apparatus 100 according to some embodiments of the present invention may include a second wafer chuck C2 that chucking a second wafer W2 and fixed above, a first wafer chuck C1 that chucking a first wafer W1 and variably positioned below, and the above-described multi-axis stage apparatus 100 that supports the first wafer W1, aligns it to a fixed position, and can bond the first wafer W1 to the second wafer W2.

[0065] Here, the second wafer chuck C2 can be either a vacuum chuck or an electrostatic chuck.

[0066] Furthermore, the multi-axis stage device 100 may have the same configuration and function as the multi-axis stage device 100 shown in Figures 1 to 9, and a detailed explanation will be omitted.

[0067] Therefore, as shown in Figures 9 to 20, the operation process of the wafer bonding apparatus 1000 according to some embodiments of the present invention will be described step by step. First, as shown in Figure 9, the second wafer transfer arm A2 can transfer the second wafer W2 below the second wafer chuck C2. At this time, the second wafer transfer arm A2 can load the second wafer W2 by vacuum adsorption of a part of the rear surface of the inverted second wafer W2 or by clamping the side surface of the second wafer W2.

[0068] At this time, the first drive unit 10 can descend with a relatively long stroke and wait in order to secure sufficient loading space for the second wafer W2.

[0069] Next, as shown in Figure 10, after the picker P of the second wafer chuck C2 picks up the second wafer W2, as shown in Figure 11, the picker P rises to bring the second wafer W2 into close contact with the second wafer chuck C2, and the second wafer chuck C2 can then vacuum-suction and chucking the attached second wafer W2. Here, in addition to the method of vacuum-suctioning the rear surface of the second wafer W2, a wide variety of picker methods are applicable, such as the method of clamping the side surface of the second wafer W2.

[0070] Next, as shown in Figure 12, the position of the second identifier M2 of the second wafer W2 vacuum-adsorbed to the second wafer chuck C2 can be confirmed using the first camera CA1 formed on the first wafer chuck C1 or the alignment stage 30. In this case, the second identifier M2 can be a separate identifier formed on the edge of the second wafer W2, or various forms of patterns formed on the front surface of the second wafer W2.

[0071] Next, as shown in Figure 13, the base portion B can be moved along the second axial direction II (see Figure 1) to a position corresponding to the second wafer chuck C2 in which the second wafer W2 is chucked, using the transfer device 40.

[0072] Next, as shown in Figure 14, the first wafer transfer arm A1 can load the first wafer W1 onto the lift pin LP of the first wafer chuck C1.

[0073] At this time, the first wafer transfer arm A1 enters above the lift pin LP while supporting the rear surface of the first wafer W1, and then, while descending to a height below the upper end height of the lift pin LP, it can transfer the first wafer W1 to the lift pin LP.

[0074] Next, as shown in Figure 15, the lift pin LP is lowered, the first wafer chuck C1 vacuum-suctions and chucking the first wafer W1, and as shown in Figure 16, the first drive device 10 can be used to raise the first wafer chuck C1 by a first distance L1 with low precision and roughly.

[0075] Next, as shown in Figure 17, using the second camera CA2 formed on the second wafer chuck C2 to photograph the first identifier M1 of the first wafer W1 and the alignment stage 30, the first wafer W1 can be precisely aligned in the first axis direction I (see Figure 1), the second axis direction II (see Figure 1), and theta axis direction R3 (see Figure 1) with respect to the second wafer W2 whose position has been confirmed.

[0076] Next, as shown in Figure 18, the first wafer chuck C1 is precisely lowered using the second drive device 20, and then, as shown in Figure 19, the base portion B can be moved along the second axial direction II (see Figure 1) to a position corresponding to the second wafer chuck C2 in which the second wafer W2 is chucked, using the transfer device 40.

[0077] Next, as shown in Figure 20, the first wafer chuck C1 can be precisely raised by a second distance L2 using the second drive device 20, thereby bonding the aligned first wafer W1 and second wafer W2. At this time, the second distance L2 is a much shorter distance than the first distance L1, and in the drawing, it may be greatly emphasized or highlighted for explanatory purposes.

[0078] Therefore, according to some embodiments of the present invention, the accuracy and process speed of wafer bonding can be greatly improved by using multiple first drive units 10, which have a long stroke but low accuracy, and second drive units 20, which have a short stroke but high accuracy, in combination for the vertical movement of the Z axis. For example, if the accuracy for repeatability was generally around +100 nanometers in the past, then in the present invention, the accuracy for repeatability can be approximately +5 nanometers or less, demonstrating a significant improvement in accuracy.

[0079] Furthermore, according to the present invention, by using the first voice coil motor 21 and the flexure joint 23, it is possible to prevent mechanical errors and component damage during multi-axis drive, and by distributing the load across multiple paths, it is possible to prevent mechanical and thermal deformation of components due to the load, thereby greatly improving the productivity, durability, and reliability of the product.

[0080] Figure 21 is a flowchart showing a wafer bonding method using a multi-axis stage apparatus 100 according to several embodiments of the present invention.

[0081] As shown in Figures 1 to 21, a wafer bonding method using a multi-axis stage apparatus 100 according to some embodiments of the present invention includes the steps of: (a) when the second wafer transfer arm A2 transfers the second wafer W2 below the second wafer chuck C2, the picker P of the second wafer chuck C2 picks up the second wafer W2 and brings the second wafer W2 into close contact with the second wafer chuck C2, and the second wafer chuck C2 vacuum-suctions and chucking the attached second wafer W2; (b) using the first camera CA1 formed on the first wafer chuck C1 or the alignment stage 30 to confirm the position of the second identifier M2 of the second wafer W2; and (c) using the first drive device 10 to roughly raise and lower the first wafer chuck C1 with low precision, and the first wafer transfer The process may include: (d) using a feed arm A1 to load the first wafer W1 onto the lift pin LP of the first wafer chuck C1, lowering the lift pin LP so that the first wafer chuck C1 vacuum-suctions and chucking the first wafer W1; (d) using a second camera CA2 formed on the second wafer chuck C2 to photograph the first identifier M1 of the first wafer W1 and an alignment stage 30 to precisely align the first wafer W1 in the first axis direction I, the second axis direction II, and theta axis direction R3 with respect to the second wafer W2 whose position has been confirmed; and (e) using a second drive device 20 having a flexible hinge portion 224 to precisely raise and lower the first wafer chuck C1 with high precision, and bonding the aligned first wafer W1 and second wafer W2.

[0082] Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely illustrative, and a person with ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true scope of technical protection of the present invention must be determined by the technical idea of ​​the appended claims. [Explanation of Symbols]

[0083] I 1st axis direction II Second axis III (Third Axis) R3 Theta axis R1 First rotation axis R2 Second rotation axis direction W1 First wafer W2 Second Wafer C1 First wafer chuck C2 Second wafer chuck B Base section 10 First drive unit L1 1st distance 11 Drive motor S threaded rod 12 movable frames N Nut Member R rail component 13,14 Support stand 20 Second drive unit L2 2nd distance 21. First voice coil motor 22 Movable platform 221 Inner column part 222 Outer column part 223 Precision Lifting Section 224 Flexible hinge section 224a Upper bridge section 224b Lower bridge section D Separation distance P1 First Route P2 Second Route P3 Third Route 23 Flexile Joint 23a Joint fixing part 23b Joint movable part 23c Joint Flexible Hinge 30 Stage Assembly 31 Stage Jig 32 Flexia Frame 321 Fixed part 322 Flexible Hinge H1 First Hinge H2 Second Hinge H3 Third Hinge 323 Moving parts 33. Second voice coil motor 331 First axis forward direction voice coil motor 332 First Axis Reverse Direction Voice Coil Motor 333 Second Axis Forward Direction Voice Coil Motor 334 Second Axis Reverse Direction Voice Coil Motor 40 Transfer device CA1 Camera 1 CA2 2nd Camera M1 First Identifier M2 Second Identifier 50 Measuring devices 60 Control Unit A1 First wafer transfer arm A2 Second wafer transfer arm P Picker LP Lift Pin 100 Multi-axis stage device 1000 wafer bonding equipment

Claims

1. The base part, An alignment stage for aligning the first wafer chucks that have the first wafer chucked in them, A first drive device is formed between the base portion and the alignment stage, and moves the alignment stage up and down with low precision. It includes a second drive device formed between the base portion and the alignment stage, which raises and lowers the alignment stage with high precision, The second drive device is A multi-axis stage device in which a flexible hinge section is formed to distribute the load to at least a portion of the device.

2. The second drive device is Multiple first voice coil motors (VCMs) are arranged at equal angles around the central axis of lifting and lowering, A movable base having a flexible hinge portion, where one part is relatively fixed and the other part can be raised and lowered relatively with high precision by the first voice coil motor, The multi-axis stage apparatus according to claim 1, further comprising a flexure joint having multiple degrees of freedom formed on the movable base.

3. The aforementioned movable platform is An inner column section formed vertically overall so that the load can be distributed along the first path, The structure is formed vertically overall so that the load can be distributed to the second path, and includes an outer column formed outward from the inner column, A precision lifting section is formed between the inner column and the outer column so that the load can be distributed to the third path, and which moves up and down with high precision by the first voice coil motor, The multi-axis stage device according to claim 2, further comprising flexible hinge portions formed between the inner column portion and the precision lifting portion, and between the outer column portion and the precision lifting portion, respectively, so as to be able to elastically support the precision lifting portion.

4. The aforementioned flexible hinge portion is An upper bridge section formed on the upper part of the aforementioned precision lifting section, The multi-axis stage apparatus according to claim 3, comprising a lower bridge section formed parallel to the upper bridge section and separated from the upper bridge section by a distance from the upper bridge section, and formed in the middle or lower part of the precision lifting section, so that the precision lifting section can be raised and lowered vertically as a whole.

5. The multi-axis stage apparatus according to claim 2, wherein the first voice coil motor is arranged in a quadrilateral or triangular configuration on the movable frame with respect to the nut member so that the first wafer can rotate in the direction of the first rotation axis or the second rotation axis.

6. The first drive device can raise and lower at least a portion of the base by a first distance in the third axial direction, The second drive device can raise and lower at least a portion of the first drive device by a second distance in the third axial direction, The multi-axis stage apparatus according to claim 1, wherein the alignment stage is connected to the second drive device so that the first wafer can move up and down in the third axis direction by a distance equal to the sum of the first distance and the second distance.

7. The first drive device can roughly raise and lower the first wafer with low precision by a first distance that is relatively longer than the second distance. The multi-axis stage apparatus according to claim 6, wherein the second drive device can raise and lower the first wafer with high precision by a second distance that is relatively shorter than the first distance.

8. The first drive device can raise and lower the first wafer with low precision of approximately micrometers or millimeters or more using a ball screw or a lead screw. The multi-axis stage apparatus according to claim 6, wherein the second drive device can raise and lower the first wafer with high precision of approximately nanometer units or less using a first voice coil motor (VCM) or a piezoelectric element.

9. The first drive device is A drive motor formed in the base portion rotates the threaded rod, The multi-axis stage device according to claim 1, comprising a movable frame on which a lifting path is guided by a rail member formed on the base portion and a nut member that moves up and down by the rotation of the threaded rod is formed.

10. The aforementioned drive motor is a DD motor (Direct Drive Motor) that directly drives the screw rod, The multi-axis stage device according to claim 9, wherein the movable frame has the nut member screwed onto the threaded rod formed in its central portion.

11. The aforementioned alignment stage is The multi-axis stage apparatus according to claim 1, wherein the first wafer is aligned in the first axis direction, the second axis direction, and theta axis direction using a second voice coil motor or a piezoelectric element.

12. The aforementioned alignment stage is Stage Jig and, A flexure frame, one part of which is fixed to the stage jig and the other part which elastically deforms with respect to the stage jig, The multi-axis stage apparatus according to claim 11, further comprising at least one second voice coil motor formed on the stage jig for elastically deforming the other portion of the flexure frame.

13. The aforementioned flexure frame is A fixing part that is fixed to the stage jig, A flexible hinge made of an elastic material is formed in the aforementioned fixed portion, The multi-axis stage apparatus according to claim 12, further comprising a movable part that supports the first wafer chuck and is precisely elastically displaced using the flexible hinge.

14. The aforementioned flexible hinge is, The first hinge is formed to be elongated in the first axial direction and elastically deforms in the second axial direction, The second hinge is formed to be elongated in the second axial direction and elastically deforms in the first axial direction, The multi-axis stage apparatus according to claim 13, further comprising a rotary hinge formed on the movable part so that the movable part can rotate in the theta axis direction.

15. The aforementioned second voice coil motor is A first axial positive voice coil motor is formed on one side of the movable part and is arranged in the positive direction in the first axial direction, A first-axis reverse-direction voice coil motor is formed on the other side of the movable part and is arranged in the opposite direction to the first axis so that the movable part can move precisely in the first axis direction or rotate precisely in the theta axis direction, A second axial positive voice coil motor is formed in the other direction of the movable part and is positioned in the positive direction in the second axial direction, The multi-axis stage apparatus according to claim 13, further comprising a second reverse-direction voice coil motor formed in another direction toward the other side of the movable part and arranged in the opposite direction to the second axis so that the movable part can move precisely in the second axis direction or rotate precisely in the theta axis direction.

16. The multi-axis stage apparatus according to claim 1, further comprising a transfer device for moving the base portion forward and backward to a position corresponding to a second wafer chuck in which the second wafer is chucked, so that the second wafer can be bonded to the first wafer.

17. A first camera formed on the first wafer chuck or the alignment stage for capturing a second identifier of the second wafer, A measuring device for measuring the lifting distance of the first wafer or the first wafer chuck, The multi-axis stage apparatus according to claim 16, further comprising a control unit that applies a control signal to at least one of the first drive unit, the second drive unit, the alignment stage, the transfer device, and any combination thereof, to which a video signal is applied from the first camera or a measurement signal is applied from the measuring device.

18. The control unit, In the first wafer loading mode, in which the first wafer is loaded into the first wafer chuck and the first wafer chuck holds the first wafer, a primary lifting control signal is applied to the first drive device. In an alignment mode in which the first wafer is precisely aligned in the first axis direction, the second axis direction and theta axis direction with respect to the second wafer whose position has been confirmed, an alignment control signal is applied to the alignment stage. The multi-axis stage apparatus according to claim 17, wherein in a bonding mode for bonding the aligned first wafer and the second wafer, a secondary lifting control signal is applied to the second drive device.

19. (a) When the second wafer transfer arm transfers the second wafer downward to the second wafer chuck, the picker of the second wafer chuck picks up the second wafer and brings the second wafer into close contact with the second wafer chuck, and the second wafer chuck chucking the second wafer that is in close contact with it; (b) A step of confirming the position of the second wafer using the first wafer chuck or the first camera formed on the alignment stage, (c) Using a first drive device, the first wafer chuck is roughly raised and lowered with low precision, and the first wafer transfer arm loads the first wafer onto the lift pin of the first wafer chuck, and the lift pin is lowered so that the first wafer chuck chucking the first wafer; (d) Using a second camera and alignment stage formed on the second wafer chuck, the first wafer is precisely aligned in the first axis direction, the second axis direction and theta axis direction with reference to the second wafer whose position has been confirmed. (e) A wafer bonding method using a multi-axis stage apparatus, comprising the steps of raising and lowering the first wafer chuck with high precision using a second drive device having a flexible hinge, and bonding the aligned first wafer and the second wafer.

20. The base part, An alignment stage for aligning the first wafer chucks that have the first wafer chucked in them, A first drive device is formed between the base portion and the alignment stage, and moves the alignment stage up and down with low precision. It includes a second drive device formed between the base portion and the alignment stage, which raises and lowers the alignment stage with high precision, The second drive device is A flexible hinge section is formed to distribute the load to at least a portion of it. The second drive device is Multiple first voice coil motors (VCMs) are arranged at equal angles around the central axis of lifting and lowering, A movable base having a flexible hinge portion, where one part is relatively fixed and the other part can be raised and lowered relatively with high precision by the first voice coil motor, The movable base includes a flexure joint having multiple degrees of freedom, The aforementioned movable platform is An inner column section formed vertically overall so that the load can be distributed along the first path, The structure is formed vertically overall so that the load can be distributed to the second path, and includes an outer column formed outward from the inner column, A precision lifting section is formed between the inner column and the outer column so that the load can be distributed to the third path, and which moves up and down with high precision by the first voice coil motor, The flexible hinge portion is formed between the inner column portion and the precision lifting portion, and between the outer column portion and the precision lifting portion, respectively, so that the precision lifting portion can be elastically supported. The first drive device can raise and lower at least a portion of the base by a first distance in the third axial direction, The second drive device can raise and lower at least a portion of the first drive device by a second distance in the third axial direction, The alignment stage is connected to the second drive unit so that the first wafer can move up and down in the third axial direction by a distance equal to the sum of the first distance and the second distance. The first drive device can roughly raise and lower the first wafer with low precision by a first distance that is relatively longer than the second distance. The second drive device can raise and lower the first wafer with high precision by a second distance that is relatively shorter than the first distance. The aforementioned alignment stage is The first wafer is aligned in the first axial direction, the second axial direction, and theta axial direction using a second voice coil motor or a piezoelectric element. The aforementioned alignment stage is Stage Jig and, A flexure frame, one part of which is fixed to the stage jig and the other part which elastically deforms with respect to the stage jig, A wafer bonding apparatus comprising at least one second voice coil motor formed on the stage jig for elastically deforming the other portion of the flexure frame.

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