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

Abstract

The present invention provides a multi-axis stage apparatus that significantly improves the accuracy of wafer bonding, as well as a wafer bonding method and apparatus using the same. [Solution] The multi-axis stage apparatus 100 includes a base portion B, a first drive device 10 formed on the base portion that can raise and lower at least a portion of it by a first distance in the direction of the third axis III with respect to the base portion, a second drive device 20 formed on the first drive device that can raise and lower at least a portion of it by a second distance in the direction of the third axis with respect to the first drive device, and an alignment stage 30 connected to the second drive device so that the first wafer can raise and lower by a distance equal to the sum of the first distance and the second distance in the direction of the third axis, and which aligns the first wafer chuck C1 that has the first wafer chucked in it.

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, and more particularly, to a multi-axis stage device capable of greatly improving the accuracy of wafer bonding, a wafer bonding method and a wafer bonding device using the same.

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 a conventional wafer bonding device, in order to ensure a sufficient stroke, for example, in order to raise and lower a wafer in the Z-axis direction using a single driving device having an accuracy in units of micrometers or millimeters, it is very difficult mechanically to ensure a high accuracy in units of 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; a first drive device formed on the base portion that can raise and lower at least a portion of the base portion by a first distance in the third axis direction with respect to the base portion; a second drive device formed on the first drive device that can raise and lower at least a portion of the first drive device by a second distance in the third axis direction with respect to the first drive device; and an alignment stage connected to the second drive device so that the first wafer can be raised and lowered by a distance equal to the sum of the first distance and the second distance, and which aligns the first wafer chuck holding the first wafer.

[0009] Furthermore, according to the present invention, the first drive device can roughly raise and lower the first wafer by a first distance that is relatively longer than the second distance, and the second drive device can precisely raise and lower the first wafer by a second distance that is relatively shorter than the first distance.

[0010] Furthermore, according to the present invention, the first drive unit can raise and lower the first wafer with low precision of approximately micrometers or millimeters or more using a ball screw or lead screw, and the second drive unit can raise and lower the first wafer with high precision of approximately nanometers or less using a first voice coil motor (VCM) or piezoelectric element.

[0011] Furthermore, according to the present invention, the first drive device may include: a drive motor formed in the base portion for rotating the threaded rod; and a movable frame on which a nut member that moves up and down as a screw rotates can be formed.

[0012] Furthermore, according to the present invention, the drive motor is a DD motor (Direct Drive Motor) that directly drives the threaded rod, and the movable frame may have the nut member screwed onto the threaded rod formed in its central portion.

[0013] Furthermore, according to the present invention, the second drive device may include: a plurality of first voice coil motors (VCMs) arranged at equiangled angles around the nut member on the movable frame; a plurality of movable platforms that are precisely raised and lowered by the first voice coil motors; and a plurality of flexure joints formed on the movable platforms and having multiple degrees of freedom.

[0014] Furthermore, according to the present invention, the first voice coil motor may be arranged in a quadrilateral or triangular configuration on the movable frame with the nut member at its center, so that the first wafer can rotate in the direction of the first rotation axis or the second rotation axis.

[0015] Furthermore, according to the present invention, the second drive device may further include at least one load compensation device formed between the base portion and the movable base, which distributes the load acting on the flexure joint portion to prevent overheating of the first voice coil motor.

[0016] Furthermore, according to the present invention, the load compensation device may include: a slider formed on the outer part of the movable table and at least a portion of which is made of a first magnetic material; a fixed body fixed to the base and at least a portion of which is made of a second magnetic material that exerts an attractive or repulsive force with the first magnetic material; and a guide bearing formed between the slider and the fixed body to guide the sliding path of the slider.

[0017] Furthermore, according to the present invention, the alignment stage can align the first wafer in the first axial direction, the second axial direction, and theta axial direction using a second voice coil motor or a piezoelectric element.

[0018] Furthermore, according to the present invention, the alignment stage may include: a stage jig; a flexure frame, one portion of which is fixed to the stage jig and the other portion of which is elastically deformable with respect to the stage jig; and at least one second voice coil motor, formed on the stage jig and causing the other portion of the flexure frame to be elastically deformed.

[0019] Furthermore, according to the present invention, the flexure frame may include: a fixed portion fixed to the stage jig; a flexible hinge formed on the fixed portion and made of an elastic material; and a movable portion that supports the first wafer chuck and is precisely elastically displaced using the flexible hinge.

[0020] Furthermore, according to the present invention, the flexure frame may further include a series amplification section comprising at least one intermediate section formed between the fixed section and the movable section and at least one series flexible hinge connecting them in series, for amplifying the stroke of the movable section by the second voice coil motor.

[0021] Furthermore, according to the present invention, the flexure frame may further include a parallel amplification section comprising at least one superimposed section formed between the fixed section and the movable section and at least one parallel flexible hinge connecting them in parallel, in order to amplify the stroke of the movable section by the second voice coil motor.

[0022] Furthermore, according to the present invention, the second voice coil motor may include: a first-axis positive voice coil motor formed in one direction of the movable part and positioned in the positive direction in the first axis direction; a first-axis reverse voice coil motor formed in the other direction of the movable part and positioned in the opposite direction in the first axis direction so that the movable part can move precisely in the first axis direction or rotate precisely in the theta axis direction; a second-axis positive voice coil motor formed in another direction of the movable part and positioned in the positive direction in the second axis direction; and a second-axis reverse voice coil motor formed in yet another direction of the movable part and positioned in the opposite direction in the second axis direction so that the movable part can move precisely in the second axis direction or rotate precisely in the theta axis direction.

[0023] Furthermore, the present invention may further include a transfer device that moves the base portion forward and backward to a position corresponding to the second wafer chuck in which the second wafer is chucked, so that the second wafer can be bonded to the first wafer.

[0024] Furthermore, according to the present invention, the present invention may further include: 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; and a control unit that receives a video signal from the first camera or a measurement signal from the measuring device and 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.

[0025] Furthermore, according to the present invention, the control unit can apply a primary lifting control signal to the first drive unit in a first wafer loading mode in which the first wafer is loaded into the first wafer chuck and the first wafer chuck chucking the first wafer; apply an alignment control signal to the alignment stage 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; and apply a secondary lifting control signal to the second drive unit in a bonding mode in which the aligned first wafer and the second wafer are bonded.

[0026] On the other hand, a wafer bonding method using a multi-axis stage device according to the idea of the present invention for solving the above problems includes: (a) when the 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, brings the second wafer into close contact with the second wafer chuck, and the second wafer chuck chucks the second wafer in close contact; (b) using the first camera formed on the first wafer chuck or the alignment stage, checking the position of the second wafer; (c) roughly raising and lowering the first wafer chuck using the first driving device, and the first wafer transfer arm loads the first wafer onto the lift pin of the first wafer chuck, and lowers the lift pin, and the first wafer chuck chucks the first wafer; (d) precisely aligning the first wafer in the first axis direction, the second axis direction, and the theta axis direction with reference to the second wafer whose position has been checked using the second camera formed on the second wafer chuck and the alignment stage; (e) precisely raising and lowering the first wafer chuck using the second driving device, and bonding the aligned first wafer and the second wafer.

[0027] On the other hand, a wafer bonding apparatus according to the concept of the present invention for solving the above problems includes: a second wafer chuck for chucking a second wafer; a first wafer chuck for chucking a first wafer; and a multi-axis stage apparatus for aligning the first wafer and bonding the aligned first wafer to the second wafer; wherein the multi-axis stage apparatus includes: a base portion; a first drive device formed on the base portion that can raise and lower at least a portion of it by a first distance in the third axis direction with respect to the base portion; a second drive device formed on the first drive device that can raise and lower at least a portion of it by a second distance in the third axis direction with respect to the first drive device; and the distance of the first wafer is the sum of the first distance and the second distance. The first drive unit includes: an alignment stage connected to the second drive unit so as to be able to move up and down in the third axial direction, and for aligning the first wafer chuck holding the first wafer; the first drive unit can roughly move the first wafer up and down by a first distance which is relatively longer than the second distance, and the second drive unit can precisely move the first wafer up and down by a second distance which is relatively shorter than the first distance; the first drive unit includes: a drive motor formed in the base portion which rotates a threaded rod; and a movable frame on which a nut member that moves up and down by the rotation of the threaded rod is formed; the second drive unit includes: a plurality of first voice coil motors (VCMs) arranged at equiangled angles around the nut member on the movable frame; The alignment stage includes a stage jig; a plurality of movable platforms that are precisely raised and lowered by the first voice coil motor; a plurality of flexure joints formed on the movable platforms and having multiple degrees of freedom; and the alignment stage may include a stage jig; a flexure frame, one portion of which is fixed to the stage jig and the other portion of which is elastically deformable with respect to the stage jig; and at least one second voice coil motor formed on the stage jig and which elastically deforms the other portion of the flexure frame. [Effects of the Invention]

[0028] According to various embodiments of the present invention made as described above, for the lifting and lowering movement of the Z-axis, by using multiple first driving devices that have low accuracy but long strokes and second driving devices that have short strokes but high accuracy, the accuracy and process speed of wafer bonding can be greatly improved. By using a voice coil motor and a flexure joint, mechanical errors during multi-axis driving and damage to components can be prevented, mechanical deformation and thermal deformation of components due to load can be prevented, and the productivity, durability, and reliability of the product can be greatly improved. Of course, the scope of the present invention is not limited by such effects.

Brief Description of the Drawings

[0029] [Figure 1] It is a side cross-sectional view showing a multi-axis stage device according to some embodiments of the present invention. [Figure 2] It is an exploded perspective view showing the components of the multi-axis stage device of FIG. 1. [Figure 3] It is an exploded perspective view showing the alignment stage of the multi-axis stage device of FIG. 2. [Figure 4] It is a conceptual diagram showing another example of the flexure frame of the alignment stage of FIG. 3. [Figure 5] It is a conceptual diagram showing yet another example of the flexure frame of the alignment stage of FIG. 3. [Figure 6] It is a cross-sectional view showing the wafer bonding process step by step using the multi-axis stage device of FIG. 1. [Figure 7] It is a cross-sectional view showing the wafer bonding process step by step using the multi-axis stage device of FIG. 1. [Figure 8] It is a cross-sectional view showing the wafer bonding process step by step using the multi-axis stage device of FIG. 1. [Figure 9] It is a cross-sectional view showing the wafer bonding process step by step using the multi-axis stage device of FIG. 1. [Figure 10] It is a cross-sectional view showing the wafer bonding process step by step using the multi-axis stage device of FIG. 1. [Figure 11]Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 12] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 13] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 14] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 15] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 16] Figure 1 is a cross-sectional view showing the wafer bonding process using a multi-axis stage apparatus in stages. [Figure 17] This flowchart shows a wafer bonding method using a multi-axis stage apparatus according to some embodiments of the present invention. [Modes for carrying out the invention]

[0030] Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The first drive unit 10 may be, for example, a type of primary lifting drive unit formed on a base unit B, which can raise and lower at least a portion of the unit in the third axis direction III by a first distance L1 (see Figure 12) with respect to the base unit B.

[0038] 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.

[0039] The second drive unit 20 is, for example, formed on the first drive unit 10 and can be a type of secondary lifting drive unit that can raise and lower at least a portion of the first drive unit 10 by a second distance L2 (see Figure 16) in the third axis direction III.

[0040] 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.

[0041] 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.

[0042] For the sake of mechanical explanation, the drawings show, for example, that the second drive unit 20 is connected above the first drive unit 10. However, it is also possible for the first drive unit 10 to be connected above the second drive unit 20.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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 for rotating the threaded rod S, and a movable frame 12 on which a nut member N that moves up and down as the threaded rod S rotates is formed.

[0047] 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.

[0048] 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.

[0049] 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 allowing the movable frame 12 to move up and down. If necessary, the moving frame 12 may be guided along its up and down path using guide members such as guide rods or rail structures.

[0050] The second drive unit 20 may include, for example, a plurality of (four in the drawings) first voice coil motors 21 (VCM) arranged equiangled around the nut member N on the movable frame 12, as shown in Figures 1 and 2; a plurality of (four in the drawings) movable tables 22 that are precisely raised and lowered by the first voice coil motors 21; and a plurality of (four in the drawings) flexure joints 23 formed on the movable tables 22 and having multiple degrees of freedom.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] On the other hand, the second drive unit 20 may further include, for example, at least one load compensation device 24 formed between the base unit B and the movable base unit 22, which distributes the load acting on the flexure joint 23 portion to prevent overheating of the first voice coil motor 21.

[0058] To give a more specific example, the load compensation device 24 may include a slider 241 formed on the outer part of the movable base 22 and at least a portion of which is made of a first magnetic material, so as to be able to use the same magnetic force characteristics as those applied to the first voice coil motor 21; a fixed body 242 fixed to the base B and at least a portion of which is made of a second magnetic material that acts attractively or repellingly with the first magnetic material; and a guide bearing 243 formed between the slider 241 and the fixed body 242 to guide the sliding path of the slider 241.

[0059] Therefore, as shown by arrows a and b in Figure 1, a portion of the load transmitted to the flexure joint 23 can be distributed so that it is transmitted to the load compensation device 24 through the direction of arrow a. This reduces the other portion of the load transmitted to the first voice coil motor 21 through the direction of arrow b. This minimizes the heat generated by the first voice coil motor 21 due to the load.

[0060] Such load compensation devices 24 are not limited to the magnetic force type shown in the illustration; various other types such as pneumatic cylinders, hydraulic cylinders, and coil springs can also be applied.

[0061] Figure 3 is an exploded perspective view showing the alignment stage 30 of the multi-axis stage device 100 shown in Figure 2.

[0062] As shown in Figures 1 to 3, 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.

[0063] 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.

[0064] Here, the second voice coil motor 33 may consist of, 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.

[0065] Therefore, for example, if the first-axis forward-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 forward-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. 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 by using the second-axis forward-direction voice coil motor 333 and the second-axis reverse-direction voice coil motor 334.

[0066] Figure 4 is a conceptual diagram showing another example of the flexure frame 32 of the alignment stage 30 in Figure 3.

[0067] As shown in Figures 3 and 4, the flexure frame 32 may further include a series amplification unit 324, which consists of at least one intermediate unit 324a formed between the fixed unit 321 and the movable unit 323, and at least one series flexible hinge 324b connecting them in series, in order to amplify the stroke of the movable unit 323 by the second voice coil motor 33.

[0068] Therefore, as shown in Figure 4, when the second voice coil motor 33 extends or contracts on the opposite side with respect to the fixed part 321, the stroke is greatly amplified by the series amplification section 324, which consists of multiple intermediate parts 324a and multiple series flexible hinges 324b connected in series with each other. As a result, even with only a small force or small displacement, a large force or large displacement can be obtained via the movable part 323.

[0069] Figure 5 is a conceptual diagram showing yet another example of the flexure frame 32 of the alignment stage 30 in Figure 3.

[0070] As shown in Figures 3 and 5, the flexure frame 32 may further include a parallel amplification unit 325, which consists of at least one superimposed portion 325a formed between the fixed portion 321 and the movable portion 323, and at least one parallel flexible hinge 325b connecting them in parallel, in order to amplify the stroke of the movable portion 323 by the second voice coil motor 33.

[0071] Therefore, as shown in Figure 5, when an external force, such as that from the second voice coil motor 33, acts on the superimposed part 325a with respect to the fixed part 321, the stroke is greatly amplified by the parallel amplification part 325, which consists of multiple superimposed parts 325a and multiple parallel flexible hinges 325b connected in parallel to each other. As a result, even with only a small force or small displacement, a large force or large displacement can be obtained via the movable part 323, and the strength can also be reinforced.

[0072] Figures 6 to 16 are cross-sectional views showing the wafer bonding process using the multi-axis stage apparatus 100 shown in Figure 1, step by step.

[0073] As shown in Figures 1 and 6, some embodiments of the present invention of the multi-axis stage apparatus 100 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.

[0074] 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.

[0075] 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.

[0076] Here, 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 loading 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.

[0077] On the other hand, as shown in Figure 6, 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 in an upward position, a first wafer chuck C1 that chucking a first wafer W1 and variably positioned downward, 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.

[0078] Here, the second wafer chuck C2 can be either a vacuum chuck or an electrostatic chuck.

[0079] 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 5, and a detailed explanation will be omitted.

[0080] Therefore, as shown in Figures 6 to 16, 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 6, 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.

[0081] At this time, the first drive unit 10 can descend with a relatively long stroke and wait so that sufficient loading space for the second wafer W2 can be secured.

[0082] Next, as shown in Figure 7, after the picker P of the second wafer chuck C2 picks up the second wafer W2, it rises and brings the second wafer W2 into close contact with the second wafer chuck C2. Then, as shown in Figure 8, the second wafer chuck C2 can 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.

[0083] Next, as shown in Figure 9, 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.

[0084] Next, as shown in Figure 10, the base portion B can be moved along the second axis direction II to a position corresponding to the second wafer chuck C2 in which the second wafer W2 is chucked, using the transfer device 40.

[0085] Next, as shown in Figure 11, the first wafer transfer arm A1 can load the first wafer W1 onto the lift pin LP of the first wafer chuck C1.

[0086] At this time, the first wafer transfer arm A1, while supporting the rear surface of the first wafer W1, enters above the lift pin LP and then descends to a height below the upper end height of the lift pin LP, thereby transferring the first wafer W1 to the lift pin LP.

[0087] Next, as shown in Figure 12, the lift pin LP is lowered, the first wafer chuck C1 vacuum-suctions and chucking the first wafer W1, and the first drive device 10 can be used to raise the first wafer chuck C1 by roughly a first distance L1.

[0088] Next, as shown in Figure 13, 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, the second axis direction II, and theta axis direction R3, with the position of the second wafer W2 as the reference.

[0089] Next, as shown in Figure 14, the first wafer chuck C1 is precisely lowered using the second drive device 20, and then, as shown in Figure 15, the base portion B can be moved along the second axial direction II to a position corresponding to the second wafer chuck C2 in which the second wafer W2 is chucked, using the transfer device 40.

[0090] Next, as shown in Figure 16, 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.

[0091] 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.

[0092] Furthermore, according to the present invention, by using the first voice coil motor 21 and the flexure joint 23, mechanical errors and component damage during multi-axis drive can be prevented, and by using the load compensation device 24, mechanical and thermal deformation of components due to load can be prevented, thereby greatly improving the productivity, durability, and reliability of the product.

[0093] Figure 17 is a flowchart showing a wafer bonding method using a multi-axis stage apparatus 100 according to several embodiments of the present invention.

[0094] As shown in Figures 1 to 17, 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 wafer chuck C1 or the first camera CA1 formed on 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, and (d) The first wafer transfer arm A1 loads the first wafer W1 onto the lift pin LP of the first wafer chuck C1 and lowers the lift pin LP so that the first wafer chuck C1 vacuum sucks in 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, the first wafer W1 is precisely aligned in the first axis direction I, the second axis direction II and the theta axis direction R3 with reference to the second wafer W2 whose position has been confirmed; and (e) Using a second drive device 20 to precisely raise and lower the first wafer chuck C1 and bond the aligned first wafer W1 and second wafer W2.

[0095] 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]

[0096] I 1st axis direction II Second axis III (Third Axis) R3 Theta axis R1 First rotation axis R2 Second rotation axis W1 First wafer W2 Second Wafer C1 First wafer chuck C2 Second wafer chuck B Base 10 First drive unit L1 1st distance 11 Drive motor S threaded rod 12 movable frames N Nut Member 20 Second drive unit L2 2nd distance 21. First voice coil motor 22 Movable platform 23 Flexile Joint 24 Load compensator 241 Slider 242 Fixed body 243 Guide bearing 30 Stage Assembly 31 Stage Jig 32 Flexia Frame 321 Fixed part 322 Flexible Hinge 323 Moving parts 324 Series Amplifier 324a middle part 324b Series Flexible Hinge 325 Parallel Amplifier Section 325a Overlap 325b Parallel Flexible Hinge 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, A first drive device formed on the base portion, which can raise and lower at least a portion of the base portion by a first distance in the third axial direction, A second drive device is formed in the first drive device and can raise and lower at least a portion of it by a second distance in the third axial direction with respect to the first drive device, A multi-axis stage apparatus comprising: a second drive unit connected to the first drive unit 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, and an alignment stage for aligning the first wafer chuck that has the first wafer chucked in it.

2. The first drive device can roughly raise and lower the first wafer by a first distance that is relatively longer than the second distance. The multi-axis stage apparatus according to claim 1, wherein the second drive device can precisely raise and lower the first wafer by a second distance that is relatively shorter than the first distance.

3. 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 2, 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.

4. 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, further comprising a movable frame on which a nut member that moves up and down by the rotation of the screw rod is formed.

5. 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 4, wherein the movable frame has the nut member screwed onto the threaded rod formed in its central portion.

6. The second drive device is The movable frame comprises a plurality of first voice coil motors (VCMs) arranged at equal angles around the nut member, Multiple movable platforms that are precisely raised and lowered by the first voice coil motor, The multi-axis stage apparatus according to claim 5, further comprising a plurality of flexure joints formed on the movable base and having multiple degrees of freedom.

7. The multi-axis stage apparatus according to claim 6, 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.

8. The second drive device is The multi-axis stage apparatus according to claim 6, further comprising at least one load compensation device formed between the base portion and the movable stage, which distributes the load acting on the flexure joint portion to prevent overheating of the first voice coil motor.

9. The aforementioned load compensation device is A slider formed on the outer part of the movable table, at least a portion of which is made of the first magnetic material, A fixed body, which is fixed to the base portion and consists of a second magnetic material in which at least a portion acts attractively or repellingly with the first magnetic material, The multi-axis stage apparatus according to claim 8, further comprising a guide bearing formed between the slider and the fixed body, which guides the sliding path of the slider.

10. 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.

11. 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 10, further comprising: at least one second voice coil motor formed on the stage jig for elastically deforming the other portion of the flexure frame.

12. 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 11, further comprising a movable part that supports the first wafer chuck and is precisely elastically displaced using the flexible hinge.

13. The aforementioned flexure frame is The multi-axis stage apparatus according to claim 12, further comprising a series amplification section comprising at least one intermediate section formed between the fixed section and the movable section and at least one series flexible hinge connecting them in series, for amplifying the stroke of the movable section by the second voice coil motor.

14. The aforementioned flexure frame is The multi-axis stage apparatus according to claim 12, further comprising a parallel amplification section comprising at least one superimposed section formed between the fixed section and the movable section and at least one parallel flexible hinge connecting them in parallel, for amplifying the stroke of the movable section by the second voice coil motor.

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 on the other side of the movable part and is positioned in the positive direction in the second axial direction, The multi-axis stage apparatus according to claim 11, 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, upon receiving a video signal from the first camera or a measurement signal 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 a first camera formed on the first wafer chuck or alignment stage, (c) The first wafer chuck is roughly raised and lowered using the first drive device, 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 (e) precisely raising and lowering the first wafer chuck using a second drive device and bonding the aligned first wafer and the second wafer.

20. A second wafer chuck for chucking the second wafer, A first wafer chuck for chucking the first wafer, The apparatus includes a multi-axis stage device for aligning the first wafer and bonding the aligned first wafer to a second wafer, The multi-axis stage device is The base part, A first drive device formed on the base portion, which can raise and lower at least a portion of the base portion by a first distance in the third axial direction, A second drive device is formed in the first drive device and can raise and lower at least a portion of it by a second distance in the third axial direction with respect to the first drive device, The first wafer is connected to the second drive device so that the first wafer can be raised and lowered in the third axial direction by a distance equal to the sum of the first distance and the second distance, and includes an alignment stage for aligning the first wafer chuck that holds the first wafer, The first drive device can roughly raise and lower the first wafer by a first distance that is relatively longer than the second distance. The second drive device can precisely raise and lower the first wafer by a second distance that is relatively shorter than the first distance. The first drive device is A drive motor formed in the base portion rotates the threaded rod, It includes a movable frame on which a nut member that moves up and down by the rotation of the screw rod is formed, The second drive device is The movable frame comprises a plurality of first voice coil motors (VCMs) arranged at equal angles around the nut member, Multiple movable platforms that are precisely raised and lowered by the first voice coil motor, The movable base includes a plurality of flexure joints having multiple degrees of freedom, 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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