Wafer bonding alignment apparatus for bonding a first wafer to a second wafer

Abstract

The application provides a wafer bonding alignment device for bonding a first wafer to a second wafer, comprising a hot plate, a spacer mechanism, an alignment mechanism, a plurality of limiting grooves pointing to the center of the hot plate are arranged on the side of the hot plate; the alignment mechanism comprises a flexible alignment assembly, a floating plate and a third driving mechanism; the floating plate is transversely provided with a guide support, the guide support forms a guide surface towards the hot plate, the flexible alignment assembly comprises a positioning assembly, a rolling body guided by the guide surface and a resisting assembly; the floating plate is driven to move up and down by the third driving mechanism, the rolling body slides under the guidance of the guide surface, the positioning assembly moves radially to expand and contract along the limiting grooves, so as to perform alignment on the edges of the first wafer and the second wafer before the first wafer and the second wafer are at least attached. The application significantly improves the wafer concentricity alignment effect, eliminates the transverse error generated in the secondary alignment process, and avoids the phenomenon of wrinkles and local missing of the bonding glue.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment, and more particularly to a wafer bonding alignment apparatus for bonding a first wafer to a second wafer. Background Technology

[0002] Wafer bonding is a wafer-level packaging technology. Reliable alignment of the wafer and carrier is a crucial preliminary step in the wafer bonding process. In the bonding equipment's process chamber, wafers and carriers of the same size are typically aligned using multiple ejector pins with arc-shaped inner supports at the lower edge of the carrier. Then, a vacuum suction robot transports the wafer above the carrier, and after calibration, places the wafer on the carrier surface.

[0003] As wafer and carrier sizes continue to increase, air residue remains between the wafer and carrier during the wafer's descent and bonding process. Even after creating a vacuum in the process chamber, voids will still form between the wafer and carrier. Furthermore, due to the unavoidable warpage of both wafers and carriers, air bubbles may accumulate between them after bonding due to van der Waals forces. Once these bubbles are trapped between the wafer and carrier, even a vacuum in the process chamber will prevent them from escaping and create voids, significantly impacting the final electrical and mechanical properties of the bonded wafer.

[0004] Meanwhile, in bonding scenarios involving homogeneous or heterogeneous wafers of the same size, whether supported by external force or falling under gravity and ultimately bonded, slight offsets occur at the edges of the two wafers. This causes misalignment of the centers and edges of the two pre-aligned wafers after bonding, negatively impacting subsequent bonding processes. Although existing technologies employ methods to align the wafers by holding their edges along the radial direction, these methods suffer from limitations due to the relatively low precision of cylinder movement, resulting in lower concentricity alignment accuracy and greater impact on the wafers. Furthermore, during the concentricity alignment of two bonded wafers of the same size, it is crucial to minimize horizontal displacement and rotation between the wafers to reduce wrinkles and partial defects in the bonding adhesive applied between their crystal faces caused by horizontal displacement and rotation.

[0005] In view of this, it is necessary to improve the existing wafer bonding alignment device to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to disclose a wafer bonding alignment device for bonding a first wafer to a second wafer, so as to reduce the above-mentioned technical defects in the process of concentric alignment of the two wafers before bonding, and in particular, to improve the concentric alignment effect of the two wafers, eliminate the phenomenon of wrinkling and partial loss of bonding adhesive between the crystal faces of the two wafers due to horizontal displacement and horizontal rotation during the concentric alignment process, and further eliminate the error generated during the concentric alignment process performed by the cylinder as the power mechanism.

[0007] To achieve the above objectives, the present invention provides a wafer bonding alignment apparatus for bonding a first wafer to a second wafer.

[0008] It includes: a hot plate, a partition mechanism, and an alignment mechanism, wherein the side of the hot plate is provided with several limiting grooves pointing to the center of the hot plate;

[0009] The alignment mechanism includes a flexible alignment component, a floating plate, and a third drive mechanism. The floating plate is laterally arranged with a guide bracket, which forms a guide surface facing the hot plate. The flexible alignment component includes a positioning component, a rolling element guided by the guide surface, and a holding component. The floating plate moves up and down under the drive of the third drive mechanism, the rolling element slides under the guidance of the guide surface, and the positioning component moves radially along the limiting groove to align the edges of the first wafer and the second wafer at least before the first wafer and the second wafer are bonded together.

[0010] As a further improvement of the present invention, the wafer bonding alignment device further includes: a limiting mechanism; the limiting mechanism includes at least two support columns with arc-shaped sidewalls formed on their inner sides facing the center of the hot plate, so that the arc-shaped sidewalls together form a circular limiting area, the limiting mechanism moves vertically to the hot plate to perform alignment of the first wafer and the second wafer through the circular limiting area, the hot plate forms a recessed portion, and the limiting groove communicates with the recessed portion.

[0011] As a further improvement of the present invention, the limiting mechanism includes: at least two support columns with top ends, a support plate connected to the support columns, and a second driving mechanism for driving the support plate to move up and down in the vertical direction.

[0012] The wafer bonding alignment device further includes a support plate disposed below the hot plate, and the alignment mechanism further includes four flexible alignment components symmetrically arranged relative to the center of the hot plate; the inner side of the end facing the center of the hot plate forms a step and an arc-shaped sidewall, the arc-shaped sidewall together enclose the circular limiting area, the support column continuously and vertically penetrates the hot plate and the support plate, and the flexible alignment components are fixedly disposed on the upper surface of the support plate.

[0013] As a further improvement of the present invention, the limiting mechanism further includes: a first guide post that penetrates vertically through the support plate and the floating plate, and a first abutting base; the floating plate further includes: a second guide post that penetrates vertically through the floating plate, and a second abutting base, wherein the first abutting base and the second abutting base form abutting surfaces at the same horizontal height.

[0014] As a further improvement of the present invention, the positioning component includes: a column, a bent portion bent toward the hot plate, and an elastic push rod assembly, wherein the bent portion forms a receiving channel for receiving the elastic push rod assembly along its extension direction.

[0015] The elastic push rod assembly includes a push rod that extends partially out of the bent portion and moves radially telescoping along the receiving channel relative to the center of the hot plate, an adjusting nut screwed into the receiving channel, and a first elastic member horizontally abutting between the adjusting nut and the push rod.

[0016] As a further improvement of the present invention, the abutment assembly includes: a support fixed to the support plate, an abutment plate, a guide shaft that horizontally penetrates the support and is connected to the column, a second elastic member that is horizontally clamped by the abutment plate and the support and sleeved on the outside of the guide shaft, and a guide sleeve that is embedded in the support and for the guide shaft to be inserted, the guide shaft penetrating the guide sleeve and horizontally rigidly connecting the column and the abutment plate, and the rolling element being provided at the bottom of the column;

[0017] When the floating plate moves up and down in the vertical direction, the rolling element slides along the guide surface, the second elastic element is held against the guide sleeve and applies elastic force to the holding plate to drive the holding plate to move closer or further away from the support, so as to drive the bending part to move radially and extend and retract along the limiting groove through the guide shaft, and the first wafer and the second wafer are laterally held against each other before bonding by the top rod.

[0018] As a further improvement of the present invention, the spacer mechanism is symmetrically arranged on both sides of the hot plate to periodically isolate the first wafer and the second wafer through the spacer mechanism;

[0019] The spacer mechanism includes: two support cantilever arms, a first drive mechanism that drives the two support cantilever arms to open and close synchronously, the ends of the support cantilever arms away from the first drive mechanism forming sheet-like parts that isolate the first wafer and the second wafer, the support cantilever arms closing synchronously to isolate the first wafer and the second wafer; during the synchronous opening of the support cantilever arms, the circular limiting area guides the second wafer to approach the first wafer and fit together with it.

[0020] As a further improvement of the present invention, when the elastic push rod assembly aligns the edges of the first wafer and the second wafer before bonding, the gap between the first wafer and the second wafer is greater than the thickness of the sheet, and the gap between the first wafer and the second wafer is less than the height formed by the push rod in its vertical direction.

[0021] As a further improvement of the present invention, the top rod aligns the edges of the first wafer and the second wafer before they are bonded together. The height of the top rod in the vertical direction is greater than the gap formed by the sheet separating the first wafer and the second wafer by a preset distance. The height of the top rod in the vertical direction covers the gap and at least partially covers the edges of the first wafer and the second wafer.

[0022] As a further improvement of the present invention, the push rod aligns the edges of the first wafer and the second wafer before bonding, and the height formed by the push rod in the vertical direction covers the edges of the first wafer and the second wafer after bonding. The first wafer and the second wafer are supported by the limiting mechanism and suspended above the recessed portion.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] In this application, the positioning component performs radial extension and retraction along the limiting groove to align the edges of the first and second wafers before bonding, thereby achieving secondary synchronous alignment. This significantly improves the concentricity alignment effect of the two wafers, eliminates the lateral error generated during the secondary concentricity alignment process powered by a cylinder, and avoids the formation of voids on the bonding surface after the first and second wafers are bonded. At the same time, since the first and second wafers are not yet bonded during the secondary concentricity alignment process, wrinkles are avoided in the bonding adhesive spin-coated on the surface of the first wafer during the secondary concentricity alignment process. Ultimately, the bonding adhesive in the bonding surface formed by the first and second wafers remains uniformly spread, thereby ensuring the yield of the wafer bonding process. Attached Figure Description

[0025] Figure 1 This is a top view of the wafer bonding alignment device for bonding a first wafer to a second wafer of the present invention when the first wafer is not loaded.

[0026] Figure 2 for Figure 1 A cross-sectional view along the GG direction;

[0027] Figure 3 for Figure 1 Sectional view along the FF direction;

[0028] Figure 4A front view of the support column included in the limiting mechanism after it rises and carries the first wafer;

[0029] Figure 5 A three-dimensional view of the support column included in the limiting mechanism supporting the first wafer after it rises;

[0030] Figure 6 A top view showing the loading of a second wafer and the simultaneous support of the first and second wafers by a support pillar, wherein the tip of the support cantilever is inserted into the gap between the first and second wafers to isolate them.

[0031] Figure 7 A partial schematic diagram showing the insertion of the tip of the cantilever between the first and second wafers;

[0032] Figure 8 A partial schematic diagram showing how the second wafer falls downwards after the cantilever opens synchronously, ensuring that the first and second wafers are in contact.

[0033] Figure 9 A partial three-dimensional view of the first and second wafers before they are aligned by the alignment mechanism after the cantilever has opened synchronously.

[0034] Figure 10 A cross-sectional view of the alignment front hot plate radially for the alignment mechanism to perform alignment on the first and second wafers;

[0035] Figure 11 A cross-sectional view along the radial direction of the hot plate after the alignment mechanism performs alignment on the first wafer and the second wafer;

[0036] Figure 12 An exploded view of the flexible alignment assembly;

[0037] Figure 13 A top view of the alignment mechanism synchronously performing radial telescoping motion in the limiting groove to align the first wafer and the second wafer;

[0038] Figure 14 A partial cross-sectional view of the alignment mechanism after it has retracted radially and retracted after performing radial extension and retraction within the limiting groove to align the first and second wafers.

[0039] Figure 15 This is a partial schematic diagram of a flexible alignment assembly before performing alignment on the edges of a first and second wafer that are not bonded, in one modified embodiment. Figure 15 The first wafer located at the bottom is not in contact with the recessed portion of the hot plate;

[0040] Figure 16 A perspective view of the end portion provided at the top of the support column of the limiting mechanism;

[0041] Figure 17 Is a perspective view of the limiting mechanism;

[0042] Figure 18 Is a top view of the floating plate;

[0043] Figure 19 Is a perspective view of the floating plate and the third driving mechanism;

[0044] Figure 20 Is a perspective view of the support cantilever of the spacer mechanism in an open state;

[0045] Figure 21 Is a perspective view of the support cantilever of the spacer mechanism in a closed state;

[0046] Figure 22 Is a top view of the support cantilever of the spacer mechanism at three limit positions. Specific embodiments

[0047] The present invention will be described in detail below in conjunction with the embodiments shown in the accompanying drawings. It should be noted, however, that these embodiments are not limitations on the present invention, and any equivalent transformation or substitution in terms of function, method, or structure made by those of ordinary skill in the art based on these embodiments shall fall within the protection scope of the present invention.

[0048] The wafer bonding alignment device (hereinafter or simply referred to as "wafer bonding alignment device") disclosed in this embodiment for bonding the first wafer 1 to the second wafer 2 is used to perform alignment on the first wafer 1 and the second wafer 2 and is applied to a wafer bonding device. Optionally, the first wafer 1 is a semiconductor wafer, for example, a silicon-based wafer, a gallium nitride wafer, etc.; the second wafer 2 is a carrier, for example, glass, sapphire, silicon carbide, etc. The second wafer 2 serves as a substrate to provide support for the first wafer 1. The first wafer 1 can form microelectronic devices through semiconductor process processes such as photolithography, etching, diffusion, deposition, cleaning, etc. The first wafer 1 and the second wafer 2 can also be homogeneous wafers, that is, both the first wafer 1 and the second wafer 2 are semiconductor wafers; further, specific examples include that both the first wafer 1 and the second wafer 2 can be silicon-based wafers with a standard thickness, or both can be thinned silicon-based wafers, or the first wafer 1 is a thinned silicon-based wafer and the second wafer 2 is a silicon-based wafer with a standard thickness, etc.

[0049] Refer Figures 1 to 4As shown, in this embodiment, the wafer bonding alignment device includes: a hot plate 20, a spacer mechanism 50, and an alignment mechanism. A plurality of limiting grooves 204 pointing to the center O1 of the hot plate are formed on the side of the hot plate 20. The limiting grooves 204 communicate with the recessed portion 201. The number of the limiting grooves 204 matches the number of the flexible positioning components, and in this embodiment, both are four. The hot plate 20 forms a recessed portion 201 that at least partially accommodates the first wafer 1 and is formed on the surface of the hot plate 20, and the recessed portion 201 is circular. The hot plate 20 forms four through holes 202 for the support columns 6 to pass through. The through holes 202 are arranged in a circular ring shape and coincide with the edge of the recessed portion 201. The recessed portion 201 is used to preheat the first wafer 1 to ensure the wafer bonding effect. In particular, in this embodiment, when the positioning components align the edges of the first wafer 1 and the second wafer 2 before bonding, the first wafer 1 and the second wafer 2 are supported by the limiting mechanism 60 and suspended above the recessed portion 201, so as to avoid the risk of slight wrinkles in the bonding glue during the second concentricity alignment process after the first wafer 1 and the second wafer 2 are bonded, and ensure that the bonding glue is evenly spread out.

[0050] As shown Figure 1 in Figure 9 Figure, the first wafer 1 and the second wafer 2 are vertically stacked. The limiting grooves 204 are arranged along the radial direction of the hot plate 20 and point to the center O1 of the hot plate. The radial direction of the limiting grooves 204 is horizontally arranged and at least extends to the edge of the circular limiting area 200. The limiting grooves 204 communicate with the recessed portion 201 to extend into the circular limiting area 200. The diameter of the circular limiting area 200 is less than or equal to the diameter of the recessed portion 201. The recessed portion 201 is circular in the top view. Preferably, a recessed portion 201 is formed by recessing downward from the upper surface 301 of the self-supporting plate 30, and another limiting groove 302 is formed. The limiting grooves 204 and the limiting groove 302 jointly point to the center O1 of the hot plate along the radial direction of the hot plate 20.

[0051] The wafer bonding alignment device can be installed in the bonding cavity included in a wafer bonding equipment (not shown), and perform two concentricity alignment operations on the first wafer 1 and the second wafer 2 to be subjected to the bonding process. After completing the concentricity alignment, it is ensured that the centers of the first wafer 1 and the second wafer 2 are concentric circles with each other (that is, the center of the first wafer 1 coincides with the center of the second wafer 2 in the top view). Then, the wafer bonding process is performed on the first wafer 1 and the second wafer 2 through the wafer bonding equipment. The diameters of the first wafer 1 and the second wafer 2 subjected to the alignment operation are the same. The bonding cavity can be connected to a vacuum equipment (not shown) to evacuate the air in the bonding cavity of the wafer bonding equipment according to the requirements of the wafer bonding process, so as to form a vacuum state corresponding to the vacuum degree inside the wafer bonding equipment to meet the requirements of wafer bonding and avoid bubbles being trapped in the bonding surface 11. Relative to bubbles, voids also need to be avoided to prevent voids from being formed in the bonding surface 11.

[0052] The alignment mechanism includes a flexible alignment component 40, a floating plate 70 and a third driving mechanism 73. The floating plate 70 is horizontally provided with a guiding bracket 702. The guiding bracket 702 forms a guiding surface 722 facing the hot plate 20. The flexible alignment component 40 includes a positioning component, a rolling body 42 guided by the guiding surface 722 and a resisting component. The floating plate 70 makes a lifting motion under the drive of the third driving mechanism 73. The rolling body 42 slides under the guidance of the guiding surface 722. The positioning component makes a radial telescopic motion along the limiting groove 204 to perform a second concentricity alignment on the edges of the first wafer 1 and the second wafer 2 at least before the first wafer 1 and the second wafer 2 are bonded together, so as to perform concentricity alignment on the first wafer 1 and the second wafer 2.

[0053] Specifically, the alignment mechanism includes four flexible alignment components 40 symmetrically arranged with respect to the center O1 of the hot plate. A support plate 30 is provided below the hot plate 20. The flexible alignment components 40 are fixedly arranged on the upper surface 301 of the support plate 30. Heating elements 211 are uniformly arranged inside the hot plate 20 and a plurality of blind holes 210 with internal threads are provided. The support plate 30 forms a number of stepped holes 310 matching the blind holes 210, and bolts are continuously passed through the stepped holes 310 and the blind holes 210 with internal threads to reliably fix the hot plate 20 and the support plate 30. The heating elements 211 are electrically connected to a power supply line 209. After the heating elements 211 are powered on, the hot plate 20 is heated to preheat the first wafer 1 by the hot plate 20. The heating elements 211 can be spirally embedded in a spiral groove (not shown) formed at the bottom of the hot plate 20. The hot plate 20 and the support plate 30 can be moved up and down and separated to facilitate the replacement of the heating elements 211.

[0054] Refer Figure 16 to Figure 17As shown, the wafer bonding alignment device further includes a limiting mechanism 60. The limiting mechanism 60 includes at least two support columns 6 with arc-shaped side walls 623 formed on the inner sides facing the center O1 of the hot plate (i.e., the superordinate concept of the column body 610), so as to jointly form a circular limiting area 200 by the arc-shaped side walls 623. The limiting mechanism 60 moves up and down perpendicular to the hot plate 20 to perform alignment on the first wafer 1 and the second wafer 2 through the circular limiting area 200. Specifically, the limiting mechanism 60 includes at least two support columns 6 with ends 620 - 650 formed at the tops. In this embodiment, the limiting mechanism 60 includes four support columns 6, a pallet 606 connecting the support columns 6, and a second driving mechanism 62 for driving the pallet 606 to move up and down in the vertical direction. Steps 622 and arc-shaped side walls 623 are formed on the inner sides of the ends 620 - 650 facing the center O1 of the hot plate, and the arc-shaped side walls 623 jointly enclose to form a circular limiting area 200. The support columns 6 continuously penetrate through the hot plate 20 and the support plate 30 located below the hot plate 20 vertically.

[0055] Refer Figure 1 to Figure 6 As shown, the ends 620 - 650 included in the limiting mechanism 60 are arranged in a cross-shaped symmetry around the outside of the hot plate 20, and form first connecting lines L1 and L2. The first connecting line L1 intersects with the first connecting line L2 and intersects at the center O1 of the hot plate of the circular limiting area 200. The four second contact points P2 formed by the support cantilever 520 and the second wafer 2 intersect with each other and pass through the center O1 of the hot plate, and form a third connecting line T1 and a fourth connecting line T2. The third connecting line T1 and the fourth connecting line T2 are symmetrically arranged with respect to the G - G sectional tangent line. The positioning component is specifically the ejector rod 491 included in the positioning component, and forms a first contact point P1 with the first wafer 1 and the second wafer 2. The connecting lines between the four first contact points P1 are obliquely arranged, intersect with each other, and pass through the center O1 of the hot plate. The two obliquely arranged first contact points P1 point to the center O3 of the second wafer 2 along the Figure 6 bidirectional arrow R1 in the figure. After the support cantilever 520 is closed synchronously, it forms a second contact point P2 with the second wafer 2. The ends 620 - 650 form a third contact point P3 with the first wafer 1. The first contact point P1 is formed between the second contact point P2 and the third contact point P3 along the circular arc trajectory formed by the concave portion 201. The flexible alignment component 40 includes four flexible alignment components 40 symmetrically arranged with respect to the center O1 of the hot plate. The connecting line of the moving directions of the two groups of flexible alignment components 40 with cross-shaped radial moving directions intersects with the center O1 of the hot plate. The connecting line T1 and the connecting line T2 formed between the two obliquely formed second contact points P2 intersect with each other, and the intersection point formed coincides with the center O3 of the second wafer 2. After the first wafer 1 and the second wafer 2 are aligned, the center O1 of the hot plate, the center O2 of the first wafer 1, and the center O3 of the second wafer 2 are arranged in concentric circles in the vertical view.

[0056] When the support cantilever 520 is in the first state, the first wafer 1 and the second wafer 2 form a preset interval distance d1 along the vertical direction, and the preset interval distance d1 is greater than or equal to the thickness of the sheet member 521 along the vertical direction. When the support cantilever 520 is in the second state, the support cantilever 520 is at least synchronously rotated to the outside of the circular limiting area 200. In this embodiment, when the support cantilever 520 is in the second state, the two support cantilever arms 520 on both sides of the hot plate 20 are in a straight line. The support cantilever 520 rotates synchronously under the drive of the first driving mechanism 51, and performs synchronous closing and opening to form the first state and the second state respectively. In both the first state and the second state, the two support cantilever arms 520 maintain a constant height along the vertical direction. The thickness of the sheet member 521 is less than the thickness of the first wafer 1 or the second wafer 2. For example, the thickness of the sheet member 521 can be set to 0.1 mm, 0.2 mm, etc. This embodiment does not specifically limit the thickness of the sheet member 521, and the sheet member 521 can be understood as a flat sheet member. The entire support cantilever 520 can be made of PTFE (polytetrafluoroethylene) or PEEK (polyether ether ketone).

[0057] Combination Figure 20 , Figure 21 As shown, two support cantilever arms 520 located on one side of the hot plate 20 are forced by the first drive mechanism 51 to move the guide end 5113 along the spiral guide groove 5091, so that the two support cantilever arms 520 on one side of the hot plate 20 rotate synchronously, performing synchronous closing and opening to form a first state and a second state respectively. In both the first and second states, the support cantilever arms 520 maintain a constant height in the vertical direction. The synchronous rotation of the two support cantilever arms 520 on both sides of the hot plate 20 ensures the synchronicity of the support cantilever arms 520 isolating the first wafer 1 and the second wafer 2, preventing the second wafer 2 from maintaining an absolutely horizontal posture when falling onto the first wafer 1, thereby effectively preventing the center of the two wafers that have already undergone two concentric circle alignment operations from deviating during the process of the second wafer 2 falling onto the first wafer 1 and finally bonding. In the wafer bonding process, bonding adhesive needs to be spin-coated onto the bonding surface 11. For example, the bonding adhesive is uniformly spin-coated onto the upper surface of the first wafer 1. Therefore, the aforementioned technical solution prevents the bonding adhesive from wrinkling and partially missing due to horizontal displacement and rotation during the second concentric alignment process, ensuring that the bonding adhesive remains uniformly spread in the bonding surface 11 and guaranteeing the wafer bonding process.

[0058] When the first wafer 1 is in the first state of the supporting cantilever 520, the first wafer 1 and the second wafer 2 form a preset interval distance d1 along the vertical direction. The preset interval distance d1 is greater than or equal to the thickness of the sheet 521 along the vertical direction, and more preferably, the preset interval distance d1 is greater than the thickness of the sheet 521 along the vertical direction. Figure 7As shown, when the supporting cantilever 520 is in its first state, the first wafer 1 and the second wafer 2 form a gap 12 with a preset interval distance d1 along the vertical direction. The preset interval distance d1 is greater than the thickness of the sheet member 521 along the vertical direction. This prevents the sheet member 521 from rubbing against and scratching the upper surface of the first wafer 1 located below during the rotation of the supporting cantilever 520 in the direction of arrow a to close or in the direction of arrow b to open. When the supporting cantilever 520 supports the second wafer 2, the sheet member 521 extends horizontally into the gap 12.

[0059] Combination Figure 7 and Figure 22 As shown, in the first state, the four support cantilever arms 520 are partially inserted into the gap 12 formed between the second wafer 2 and the first wafer 1 before they are bonded; in the second state, the four support cantilever arms 520 are at least synchronously rotated to the outside of the circular limiting region 200 to release the horizontal supporting effect on the second wafer 2. Specifically, in the first state, the support cantilever arms 520 are partially inserted into the gap 12 formed between the second wafer 2 and the first wafer 1 before they are bonded; in the second state, the support cantilever arms 520 are at least synchronously rotated to the outside of the circular limiting region 200. The support cantilever arms 520 along... Figure 20 The central axis e and axis f rotate horizontally, and the two support cantilever arms 520 located on one side of the hot plate 20 rotate horizontally along... Figure 20 The central axis e and axis f rotate horizontally, and the two supporting cantilever arms 520 located on the other side of the hot plate 20 also rotate horizontally. Figure 20 The central axis e and axis f rotate horizontally. Therefore, in the second state, when the support cantilever 520 located on one side of the hot plate 20 rotates synchronously to the open state, it is not required that the support cantilever 520s included in the spacer mechanism 50 be in a straight line; it is sufficient that they disengage from the lower surface of the second wafer 2. At this time, the second wafer 2 falls down onto the first wafer 1 and finally completes alignment and bonding with it. Therefore, by having the support cantilever 520 rotate synchronously at least to the outside of the circular limiting area 200, the process time consumed by the rotation of the support cantilever 520 can be further reduced, indirectly improving the bonding efficiency of the wafer bonding equipment.

[0060] Furthermore, participants Figure 22 As shown, in the first state, the support cantilever 520 is partially inserted into the gap 12 formed between the second wafer 2 and the first wafer 1 before they are bonded, thereby causing the four support cantilever 520 to present an appearance similar to Figure 22 In the second state, the support cantilever 520a is positioned such that the sheet member 521 enters the circular limiting region 200 and supports the second wafer 2. When in this second state, the support cantilever 520 is at least synchronously rotated to the outside of the circular limiting region 200. The support cantilever 520 being synchronously rotated to the outside of the circular limiting region 200 means that the support cantilever 520 is positioned as follows: Figure 22 Any state between the middle support cantilever 520c and the support cantilever 520b, so that in the second state, the four support cantilevers 520 release the support for the second wafer 2. The support cantilever 520a, the support cantilever 520b, and the support cantilever 520c are three extreme positions of the support cantilever 520.

[0061] During the synchronous opening process of the two support cantilevers 520 on one side of the hot plate 20 and the two support cantilevers 520 on the other side of the hot plate 20, the frictional force formed by the support cantilever 520 and the bottom surface of the second wafer 2 is always symmetrically arranged with respect to the sectional plane in the G-G direction, so that when the two support cantilevers 520 respectively included in the spacer mechanism 50 symmetrically arranged on both sides of the hot plate 20 perform the synchronous opening or closing process, a stable and balanced force is always formed on the second wafer 2, thereby effectively avoiding the displacement of the second wafer 2 caused during the rotational process of the synchronous opening of the support cantilever 520, ensuring that the centers of the first wafer 1 and the second wafer 2 always coincide with each other, and avoiding damage to the concentricity alignment effects of the first time and the second time.

[0062] See Figure 1 , Figure 20 and Figure 21 As shown, in this embodiment, two spacer mechanisms 50 are symmetrically arranged on both sides of the hot plate 20, and each spacer mechanism 50 includes a first driving mechanism 51. Specifically, the first driving mechanism 51 includes: a first power unit 501, a fixed seat 504, a moving block 502 driven by the first power unit 501 and performing a lifting action in the vertical direction, a driving shaft 506 connecting the moving block 502, two rotating shafts arranged in parallel and perpendicular to each other and respectively driving the support cantilever 520 to rotate, the support cantilever 520, and a synchronous block 507; spiral guiding grooves 5091 are symmetrically formed on the side walls of the two rotating shafts 509, and guiding ends 5113 extending into the spiral guiding grooves 5091 are symmetrically formed on the synchronous block 507. When the synchronous block 507 moves up and down in the vertical direction, the guiding ends 5113 slide in the spiral guiding grooves 5091 to synchronously drive the two support cantilevers 520 to perform synchronous opening and closing. The driving shaft 5011 of the first power unit 501 is connected to the moving block 502 to perform a telescopic movement in the vertical direction through the driving shaft 5011, so as to drive the synchronous block 507 to move downward in the Z2 direction in Figure 20 or drive the synchronous block 507 to move upward in the Z1 direction in Figure 21 .

[0063] The first driving mechanism 51 includes: a first power unit 501 (such as a cylinder or a linear motor, etc.), a fixed seat 504, a moving block 502 driven by the first power unit 501 and performing a lifting motion in the vertical direction, a driving shaft 506 connecting the moving block 502, a rotating shaft 509 respectively driving two vertically and parallel arranged support cantilever 520 to rotate, a support cantilever 520 driven by the driving shaft 509 and performing a horizontal rotation along axis e and axis f, and a synchronization block 507. Helical guide grooves 5091 are symmetrically formed on the side walls of the two rotating shafts 509, and guide ends 5113 extending into the helical guide grooves 5091 are symmetrically formed on the synchronization block 507. The two rotating shafts 509 remain parallel during rotation. The first power unit 501 drives the block 502 to perform a linear lifting motion in the vertical direction where Z1 and Z2 are located. A bending portion 4151 is formed at the top of the fixed seat 504, and the bending portion 4151 is fixedly connected to the bottom plate 15 by screws, and the bottom plate 15 is part of the base 10; a baffle 4152 is formed at the bottom of the fixed seat 504. The moving block 502 is slidably connected to a guide rail 514 which is perpendicular to the side of the fixed seat 504 facing the slider 524 through a slider 524. The moving block 502 is connected to the driving shaft 506, and a diameter-reduced end 4171 longitudinally inserted into the mounting seat 505 is formed at the free end of the driving shaft 506. The driving shaft 506 is sleeved with the mounting seat 505, and the mounting seat 505 is fixed to the support plate 30 by screws. A bellows 503 made of, for example, stainless steel is axially clamped between the mounting seat 505 and the moving block 502 to prevent external air from entering the bonding cavity through the bellows 503 and can play a role in assisting power transmission. The driving shaft 506 vertically extends out of the mounting seat 505.

[0064] The synchronization block 507 is vertically connected to the driving shaft 506. A connecting cylinder 513 is axially sleeved between the driving shaft 506 and the mounting seat 505. The driving shaft 506 vertically extends through the synchronization block 507 and is fixed by a nut 5061. The synchronization block 507 is connected to the guide ends 5113 extending into the helical guide grooves 5091 through two bending members 511. The rotating shaft 509 respectively symmetrically forms a helical guide groove 5091 in the vertical direction. The bending member 511 includes a first bending portion 5111 connecting the rotating shaft 509 and a second bending portion 5112 connecting the synchronization block 507. The second bending portion 5112 is fixedly connected to the synchronization block 507 by screws. The first bending portion 5111 forms a pin shaft (not shown) axially connecting the guide end 5113. When the first power unit 501 drives the driving shaft 506 to perform a lifting motion in the vertical direction, the guide ends 5113 are synchronously driven by the synchronization block 507 to move in the helical guide grooves 5091 to drive the two support cantilever 520 to perform opening or closing synchronously.

[0065] See Figure 20 Refer to Figure 21As shown, the first driving mechanism 51 further includes: a holding bracket that keeps the heights of the two rotating shafts 509 constant in the vertical direction during rotation. The holding bracket includes: a cross plate 508, two vertical plates 533 that are perpendicular to the cross plate 508 and are parallel and perpendicular to the horizontal plane. Opposite inner sides of the two vertical plates 533 form positioning blocks 510 through which the two rotating shafts 509 vertically penetrate and are arranged oppositely. The positioning blocks 510 are located inside the two vertical and parallel rotating shafts 509. The bottom free end portions of the rotating shafts 509 away from the support cantilever 520 extend into the cross plate 508, and a bearing 5081 is sleeved between the bottom free ends of the rotating shafts 509 and the cross plate 508, so that the rotating shafts 509 can rotate in the two cross plates 508.

[0066] The wafer bonding alignment device is located in a wafer bonding equipment (not shown), applies pressure to the upper surface of the second wafer 2 under the action of an external force, and completes wafer bonding. The two bonded wafers are driven by the second driving mechanism 62 again and lifted to a set height in the vertical direction, and the first wafer 1 is separated from the hot plate 20. Then, the wafer bonding equipment is opened, and the bonded first wafer 1 and second wafer 2 are taken out from the bonding cavity formed by the upper cover and the lower cover included in the wafer bonding equipment through a pick-and-place robot arm (not shown) or a Bernoulli chuck (not shown).

[0067] See Figure 2 、 Figure 3 and Figure 17As shown, the limiting mechanism 60 moves vertically up and down perpendicular to the hot plate 20. The limiting mechanism 60 includes: four support columns 6 with top ends 620-650, a support plate 606 connecting the support columns 6, and a second drive mechanism 62 driving the support plate 606 to move vertically up and down. The second drive mechanism 62 includes: a second power unit 601 (e.g., a cylinder or linear motor), a fixed seat 607, a sliding seat 611, a track between the fixed seat 607 and the sliding seat 611, and a slider (not shown) moving linearly along the track. Since the sliding connection technology configured between the fixed seat 607 and the sliding seat 611 is a mature prior art, it is not described in detail in this embodiment. The top of the fixed seat 607 forms a bent portion 617, which is installed to the bottom of the support plate 30 by screws and kept stationary. The top of the sliding seat 611 is provided with a horizontally arranged mounting plate 602. A vertically arranged column 605 is provided at the top of the mounting plate 602, which vertically passes through the mounting base 604 and is vertically fixedly connected to the support plate 606. The mounting base 604 is fixed to the support plate 30 by screws. A corrugated pipe 603 made of stainless steel is provided between the mounting base 604 and the mounting plate 602 to assist in power transmission. The column 605 passes through the corrugated pipe 603 in a vertical direction. The bottom of the support plate 606 is connected to the column 605, which extends through the support plate 606 and is fixed by screws. When the second drive mechanism 62 moves in a vertical direction, it drives the sliding seat 611 to perform a lifting motion relative to the fixed base 607, and ultimately drives the support plate 606 to move in a vertical direction, so as to synchronously drive the four support columns 6 to move in a vertical direction.

[0068] In this embodiment, the structures of ends 620 to 650 are identical; therefore, the applicant uses end 620 as an example for illustrative explanation. (See reference...) Figure 16 As shown, the end 620 includes an end body 621. The inner side of the end body 621 facing the center O1 of the hot plate forms a step 622 and an arc-shaped sidewall 623, so that the arc-shaped sidewalls 623 of the four ends collectively enclose a circular limiting region 200. A bolt 624 is provided at the top of the end body 621, which vertically penetrates the end body 621 and is screwed to the column 610 for fixation. Thus, the end 620 and the column 610 can be movably assembled and connected by unscrewing or screwing in the bolt 624. The diameter of the circle formed by the circular limiting region 200 in a top view is slightly larger than the diameters of the first wafer 1 and the second wafer 2.

[0069] The support plate 606 has four through holes for the guide seat 612 to be inserted, and the first guide post 608 penetrates vertically through the guide seat 612. The four first guide posts 608 move up and down in the four guide seats 612, thereby ensuring the stability of the four support posts 6 when moving up and down in the vertical direction. This effectively prevents the four steps 622 of the ends 620~650 formed at the top of the support posts 6 from being on the same horizontal plane, thereby improving the holding effect of the first wafer 1 and ensuring that the first wafer 1 always maintains a horizontal posture.

[0070] The limiting mechanism 60 further includes: a first guide post 608 that vertically penetrates the support plate 606 and the floating plate 70, and a first abutting base 609. The floating plate 70 further includes: a second guide post 703 that vertically penetrates the floating plate 70, and a second abutting base 713, wherein the first abutting base 609 and the second abutting base 713 form abutting surfaces 113 at the same horizontal height. (See reference...) Figure 2 As shown, the abutment surface 113 is integrally enclosed by the lower cover (not shown) of the wafer bonding alignment device. The lower cover is a component of the wafer bonding equipment. The lower cover is a rectangular hollow cube with an open top surface. The bottom surface of the lower cover forms a base plate (not shown) that supports the first abutment base 609 and the second abutment base 713. The abutment surface 113 is formed on the contact plane where the first abutment base 609 and the second abutment base 713 abut against the aforementioned base plate. At the same time, the horizontal plates 508 included in the two spacer mechanisms 50 on both sides of the hot plate 20 are also fixed to the base plate of the lower cover by bolts.

[0071] The wafer bonding apparatus includes an upper cover (not shown) that can be opened or closed. The upper cover and lower cover together enclose a bonding cavity. More specifically, see... Figure 19 As shown, the floating plate 70 includes three second guide posts 703 penetrating the floating plate 70, and a drive shaft 735 is located inside the triangular area formed by the three second guide posts 703. Each second guide post 703 has a sleeve 723 fixedly connected to the floating plate 70 at its top. The sleeve 723 and a sleeve mounting block 704 embedded in a recessed area above the floating plate 70 form an integral structure. The mounting block 704 is reliably mounted in the recessed area above the floating plate 70 by two bolts passing through the mounting block 704 and the floating plate 70 from top to bottom. The second guide posts 703 are guided by the sleeves 723 and move up and down within the sleeves 723, making the floating plate 70 more stable when moving up and down. This ensures that the floating plate 70 has good rigidity when driven by the third drive mechanism 73, thereby ensuring that the four flexible alignment components 40 can synchronously perform secondary concentricity alignment on the edges of the first wafer 1 and the second wafer 2 before bonding.

[0072] The floating plate 70 is located below the support plate 30 and is movably separated from and in contact with the support plate 30. When separated, the floating plate 70 is at the bottom dead center, and when in contact, the floating plate 70 is at the top dead center. The drive shaft 735 is vertically arranged with respect to the floating plate 70 and extends through the floating plate 70 without any interference or contact with the floating plate 70. The free end at the top of the drive shaft 735 is fixedly connected to the floating plate 70 through a fastener 736. Refer Figure 18 As shown, the floating plate 70 forms four avoidance holes 701 symmetrically arranged in a square shape. A sleeve (not shown) through which the first guide post 608 vertically penetrates is accommodated in the avoidance holes 701, so that the up-and-down movement of the four columns 610 included in the limiting mechanism 60 in the vertical direction is more stable, ensuring the supporting effect of the columns 610 on the first wafer 1 and the second wafer 2, and ensuring that the two wafers always maintain a horizontal posture. Four guiding brackets 702 are fixed to the side of the floating plate 70 by screws.

[0073] Refer Figures 10 to 12 As shown, in this embodiment, the positioning component includes: a column 41, a bending part 43 bent towards the hot plate 20, and an elastic ejector rod component 49. An accommodation channel 430 for accommodating the elastic ejector rod component 49 is formed inside the bending part 43 along its extending direction. The elastic ejector rod component 49 includes an ejector rod 491 partially extending out of the bending part 43 and performing a radial telescopic movement relative to the center O1 of the hot plate along the accommodation channel 430, an adjusting nut 493 screwed to the accommodation channel 430, and a first elastic member 492 horizontally abutted between the adjusting nut 493 and the ejector rod 491. The ejector rod 491 includes an ejector rod body 4910 moving in the accommodation channel 430 along the two-way arrow R1 direction and a abutting column 4911 integrally structured with the ejector rod body 4910 and exposed at the end of the bending part 43 facing the hot plate 20.

[0074] The abutting component includes: a support 44 fixed to the support plate 30, an abutting plate 47, a guide shaft 45 horizontally penetrating the support 44 and connected to the column 41, a second elastic member 46 horizontally clamped between the abutting plate 47 and the support 44 and sleeved outside the guide shaft 45, and a guide sleeve 48 embedded in the support 44 and into which the guide shaft 45 is inserted; the guide shaft 45 penetrates the guide sleeve 48 and horizontally and rigidly connects the column 41 and the abutting plate 47, and a rolling body 42 is provided at the bottom of the column 41. When the floating plate 70 moves up and down in the vertical direction, the rolling body 42 slides along the guiding surface 722, and the second elastic member 46 is abutted against the guide sleeve 48 and applies an elastic force to the abutting plate 47 to drive the abutting plate 47 to move closer to or away from the support 44, so as to drive the bending portion 43 to perform a radial telescopic movement along the limiting groove 204 through the guide shaft 45, and laterally abut the edges of the first wafer 1 and the second wafer 2 through the ejector rod 491, specifically through the abutting column 4911, so that the four abutting columns 4911 driven synchronously perform secondary alignment on the first wafer 1 and the second wafer 2 before bonding, thus ensuring that the centers of the first wafer 1 and the second wafer 2 are concentrically arranged. Another combination Figure 9 As shown, the support 44 included in the flexible alignment component 40 is fixed to the support plate 30 in a vertical posture. During the process of the abutting column 4911 performing secondary alignment on the edges of the first wafer 1 and the second wafer 2, the support 44 is kept in a fixed state. The abutting plate 47, the guide shaft 45 and the column 41 form an integral component.

[0075] Refer Figure 10 As shown, the second elastic member 46 forms an elastic force F1 on the abutting plate 47, and the second elastic member 46 forms an elastic force F2 on the guide sleeve 48. At this time, the floating plate 70 is separated from the support plate 30 as shown in Figure 15 to form a lower dead point position. At this time, the abutting column 4911 does not laterally abut the edges of the first wafer 1 and the second wafer 2. Refer Figure 11 As shown, the second elastic member 46 forms an elastic force F3 on the abutting plate 47, and the second elastic member 46 forms an elastic force F4 on the guide sleeve 48. The second elastic member 46 is compressed by the abutting plate 47 and the support 44 in the direction pointing to the center O1 of the hot plate. At this time, the floating plate 70 is in contact with the support plate 30 as shown in Figure 16 to form an upper dead point position. At this time, the abutting column 4911 laterally abuts the edges of the first wafer 1 and the second wafer 2 to perform secondary alignment. The elastic force F1 is equal to the elastic force F2, and the elastic force F3 is equal to the elastic force F4 and is greater than the elastic forces F1 and F2.

[0076] Refer Figure 9As shown, a circular gap 203 is formed in a circumferential direction along the radial direction of the hot plate 20 between the first wafer 1 and the second wafer 2 before and after lamination and the recessed portion 201. At this time, the end heads 620 at the tops of the four support columns 6 support the two laminated wafers, and a gap with a height of H2 is formed in the vertical direction between the first wafer 1 below and the recessed portion 201. Then, the third driving mechanism 73 drives the floating plate 70 to move upward. The bending portion 43 drives the upright column 41 including the bending portion 43 to move in the direction pointing to the center O1 of the hot plate along the bidirectional arrow R1 direction under the drive of the second elastic member 46 and under the guidance of the limiting groove 204 and the limiting groove 302, so as to laterally abut against the edges of the first wafer 1 and the second wafer 2 by the abutting column 4911, so as to align the edges of the first wafer 1 and the second wafer 2 before laminating the first wafer 1 and the second wafer 2, so as to complete the second concentricity alignment.

[0077] As shown in Figures 10 to 13 the figure, flush positioning seats 441 are respectively formed at the lateral two ends of the support 44. The positioning seats 441 form screw holes 442 with internal threads. A bolt is passed through the screw hole 442 and screwed and fixed with a corresponding screw hole (not shown) opened on the support plate 30. The upright column 41 is provided with a through hole 411 for the horizontal penetration of the guide shaft 45. The support 44 is provided with an embedding hole 443 for the integral embedding of the guide sleeve 48. The guide shaft 45 horizontally penetrates through the guide sleeve channel 481 opened in the guide sleeve 48 and is screwed and fixed with the through hole 411. Specifically, there are two embedding holes 443 which are arranged vertically. Optionally, as shown in Figure 12 the figure, blind holes 451 and 452 with internal threads can be respectively arranged at the two ends of the guide shaft 45. A bolt horizontally penetrates through the through hole 471 opened in the abutting plate 47 and the through hole 411 opened in the upright column 41, and is screwed into the blind holes 451 and 452, so as to horizontally connect the abutting plate 47 and the upright column 41 through the guide shaft 45. Since the support 44 is also fixed on the upper surface 301 of the support plate 30. Therefore, the elastic force generated by the second elastic member 46 along its longitudinal direction (i.e., the direction of the bidirectional arrow R1) can drive the upright column 41 to move integrally in the direction pointing to the center O1 of the hot plate 20. The rolling body 42 slides on the guiding surface 722 formed by the guiding bracket 702 facing the hot plate 20, so as to control the feeding degree of the abutting column 4911 in the radial direction of the hot plate by controlling the height of the floating plate 70 in the vertical direction. The support 44 is kept fixed during the telescopic movement of the abutting column 4911 in the radial direction of the hot plate 20.

[0078] As shown in Figure 3 and Figure 10 and Figure 14As shown, when the floating plate 70 is at the bottom dead center, the floating plate 70 is separated from the support plate 30. At this time, a gap with a horizontal distance W1 is formed between the column 41 and the support 44 in the direction of the double-headed arrow R1, or they can be in direct contact. The length of the ejector rod 491 that horizontally protrudes from the hollow alignment body and is exposed outside the hollow alignment body is X1. At this time, the ejector rod 491 does not contact the edge 110 of the first wafer 1 and the edge 220 of the second wafer 2.

[0079] Refer Figure 11 to Figure 14 As shown, when the floating plate 70 is at the top dead center, the floating plate 70 contacts the support plate 30 and horizontally holds the edge 110 of the first wafer 1 and the edge 220 of the second wafer 2 through the ejector rod 491. At this time, a gap with a horizontal distance W2 is formed between the column 41 and the support 44 in the direction of the double-headed arrow R1. The length of the ejector rod 491 that horizontally protrudes from the hollow alignment body and is exposed outside the hollow alignment body is X2. W2 is greater than W1, and X1 is greater than X2.

[0080] Refer Figure 12 As shown, two bifurcated portions for accommodating the rolling elements 42 are formed at the bottom of the column 41, and through holes 412 are formed in the bifurcated portions. The rolling elements 42 are configured as bearings and a shaft portion 421 that penetrates through the bearings and is fixedly connected to the inner ring of the bearings. A positioning surface 422 is formed at the end of the shaft portion 421 that horizontally protrudes from the inner ring. Through holes 413 that are vertically arranged and have internal threads are formed at the bottom of the bifurcated portions. The shaft portion 421 penetrates through the through holes 412, and bolts penetrate through the through holes 413 from bottom to top and abut against the positioning surface 422.

[0081] Refer Figure 14 to Figure 15 As shown, when the positioning component, specifically the elastic ejector rod component 49, aligns the edges of the first wafer 1 and the second wafer 2 before fitting, the height formed by the abutting column 4911 in the vertical direction completely covers the edges of the first wafer 1 and the second wafer 2 after they are fitted together. Further, the height formed by the abutting column 4911 in the vertical direction also completely covers the edges of the first wafer 1 and the second wafer 2 after they are fitted together and removed from the support cantilever 520. At the same time, the cross-sectional shape of the abutting column 4911 in this embodiment is not specifically limited, and the height formed by the holding column 4911 in the vertical direction can continuously cover the horizontal area of the recessed portion 201, so that the operation of secondary concentricity alignment can also occur in the application scenario after the first wafer 1 and the second wafer 2 are fitted together.

[0082] The top surface 6231 of the end body 621 of the end 620 is higher than the upper surface of the second wafer 2 before bonding. Thus, the top surface 6231 of the end body 621 is also higher than the upper surface of the second wafer 2 before bonding. The edge of the recessed portion 201 forms an annular boundary 201a in the vertical direction, and the circular limiting region 200 forms an annular boundary 200a in the vertical direction. The annular boundary 201a is located radially outside the annular boundary 200a in the radial direction of the hot plate 20. The abutting column 4911 formed at the end of the bending portion 43 makes a radial telescopic movement in the receiving channel 430 to abut the edge 110 of the first wafer 1 and the edge 220 of the second wafer 2 through the abutting column 4911. Due to the synchronous movement of the four abutting columns 4911 during the vertical lifting movement of the floating plate 70, the edge 110 of the first wafer 1 and the edge 220 of the second wafer 2 can be abutted synchronously to perform the second concentricity alignment. At the same time, since the floating plate 70 is driven by the third driving mechanism 73, the lateral error generated during the second concentricity alignment process (i.e., the second concentricity alignment) of the third driving mechanism 73 using a cylinder as a power execution mechanism is eliminated, avoiding the formation of voids on the bonding surface after the first wafer and the second wafer are bonded. The aforementioned lateral error includes the errors generated by horizontal displacement and horizontal rotation.

[0083] When the first wafer 1 and the second wafer 2 are supported by the four support cantilever arms 520 and separated from each other, the edge 110 of the first wafer 1 and the edge 220 of the second wafer 2 basically coincide under a top view angle under the guidance of the four ends 620 - 650 forming the circular limiting region 200. Before bonding, the surface of the first wafer 1 facing the second wafer 2 is uniformly coated with bonding glue. When the first wafer 1 and the second wafer 2 are before bonding, the four abutting columns 4911 that move synchronously in the radial direction are used to perform the second concentricity alignment operation on the edges of the first wafer 1 and the second wafer 2 before bonding, so that the bonding glue in the bonding surface 11 formed by the first wafer 1 and the second wafer 2 remains in a uniformly spread state, thereby ultimately ensuring the process yield of wafer bonding. Given that the bonding glue is not the inventive point of this application and is very thin, the bonding glue is omitted from being shown in the respective drawings included in this application and no reference numerals are marked. After the second concentricity alignment operation is completed, the four support cantilever arms 520 are synchronously opened, so that the second wafer 2 drops onto the first wafer 1 and is finally bonded. Since the sheet-like member 521 at the end of the support cantilever arm 520 is very thin, the concentricity displacement caused during the bonding process of the second wafer 2 to the first wafer 1 can be basically ignored.

[0084] See Figure 1 、 Figure 20 And Figure 21As shown, the spacer mechanism 50 is symmetrically arranged on both sides of the hot plate 20 to periodically isolate the first wafer 1 and the second wafer 2. The spacer mechanism 50 includes two support cantilever arms 520, a first drive mechanism 51 that drives the two support cantilever arms 520 to open and close synchronously, and the ends of the support cantilever arms 520 away from the first drive mechanism 51 forming sheet-like members 521 that isolate the first wafer 1 and the second wafer 2. The support cantilever arms 520 close synchronously to isolate the first wafer 1 and the second wafer 2. During the synchronous opening of the support cantilever arms 520, the second wafer 2 is guided to approach and fit against the first wafer 1 through the circular limiting area 200. The two support cantilever arms 520 on one side of the hot plate 20 are relative to each other. Figure 1 The GG-direction section (i.e., Figure 1 The dashed line P is perpendicular to the plane of the paper and is symmetrically distributed and rotates synchronously.

[0085] For example, such as Figure 1 As shown, in the initial state before the first wafer 1 and the second wafer 2 are loaded, two spacer mechanisms 50 are symmetrically arranged on both sides of the hot plate 20, and two flexible alignment components 40 are symmetrically arranged on both sides of the spacer mechanisms 50. The two spacer mechanisms 50 are arranged along... Figure 1 Two flexible alignment components 40 are symmetrically arranged on both sides of the central GG direction, thereby allowing the four flexible alignment components 40 to align along the GG direction. Figure 6 The two arrows R1 in the middle point in the same direction. Figure 1 The hot plate center O1 is shown, and the edges of the first wafer 1 and the second wafer 2 are aligned before bonding by performing synchronous radial extension and retraction movements, so as to perform concentric alignment of the first wafer 1 and the second wafer 2.

[0086] Four flexible alignment components 40 are divided into two groups, with each group of flexible alignment components 40 symmetrically arranged on both sides of the spacer mechanism 50 along the GG direction section plane. In the initial state without loading the first wafer 1 and the second wafer 2, neither of the two flexible alignment components 40 on each side is in contact with the first wafer 1 and the second wafer 2. The abutment posts 4911 included in the flexible alignment components 40 are separated from the edges of the first wafer 1 and the second wafer 2. The spacer mechanism 50 includes two synchronously opening or closing support cantilever 520 as shown in the figure. Figure 1 As shown, the device is in an open state, at which point the two support cantilever arms 520 included in the two partition mechanisms 50 on the left and right sides of the hot plate 20 are in a straight line. The support cantilever arms 520 rotate synchronously under the drive of the first drive mechanism 51 and move along... Figure 1 The direction of the middle arrow a is synchronously rotated, so that the sheet 521 formed at the end of the support cantilever 520 is located inside the circular limiting area 200. The tip 522 formed at the end of the sheet 521 is inserted into the gap 12 between the unattached first wafer 1 and the second wafer 2 to isolate the first wafer 1 and the second wafer 2 and support the second wafer 2.

[0087] As shown Figure 7 in the figure, an arc transition surface 523 is formed between the sheet-like member 521 and the support cantilever 520 below the support cantilever 520. The arc transition surface 523 does not contact the edge 110 of the first wafer 1 located below during the process of the sheet-like member 521 rotating and inserting into or moving out of the gap 12. The support cantilever 520 rotates reversely and synchronously under the drive of the first drive mechanism 51, and rotates synchronously along the Figure 1 direction of the arrow b in the figure, and makes the sheet-like member 521 formed at the end of the support cantilever 520 rotate synchronously to leave the inside of the circular limit area 200. When the second wafer 2 located above is not supported by the four sheet-like members 521, the second wafer 2 drops downward onto the first wafer 1 and adheres to the first wafer 1 to form a bonding surface 11. The sheet-like member 521 formed at the end of the support cantilever 520 rotates synchronously to leave the circular limit area 200 and resumes to the linear arrangement state of the support cantilever 520 as shown Figure 1 in the figure. The tip 522 is part of the sheet-like member 521, and when the tip 522 contacts the bottom surface of the second wafer 2, it is approximately a triangular contact surface, so as to reduce the contact area formed between the support cantilever 520 and the bottom surface of the second wafer 2, and further reduce the scratches caused by the support cantilever 520 on the bottom surface of the second wafer 2 during the synchronous opening or closing process.

[0088] Refer Figure 1 to Figure 9 the figure shown. In this embodiment, the hot plate 20 forms a recessed portion 201, and a limit groove 204 communicating with the recessed portion 201 is opened on the side of the hot plate 20. The hot plate 20 forms a recessed portion 201 that at least partially accommodates the first wafer 1 and is formed on the surface of the hot plate 20. The recessed portion 201 is circular. The hot plate 20 forms four through holes 202 for the support columns 6 to pass through. The through holes 202 are arranged in a circular ring and coincide with the edge of the recessed portion 201. The recessed portion is used for preheating the first wafer 1 to ensure the effect of the subsequent wafer bonding process. The four ends can completely descend into the inside of the through holes 202, and it is ensured that the first wafer 1 can be completely adhered to the recessed portion 201 to ensure the uniformity of the preheating process performed on the first wafer 1. The recessed portion 201 is recessed in the upper surface 205 of the hot plate 20 in the vertical direction.

[0089] Optionally, the wafer bonding alignment device disclosed in this embodiment can be installed in the bonding cavity included in a wafer bonding equipment (not shown), and perform two concentricity alignment operations on the first wafer 1 and the second wafer 2 to be subjected to the bonding process. After alignment, the wafer bonding process is performed on the first wafer 1 and the second wafer 2 by the wafer bonding equipment to ensure that the centers of the first wafer 1 and the second wafer 2 are concentric circles with each other (that is, the center O2 of the first wafer 1 coincides with the center O3 of the second wafer 2 in the top view). Optionally, the first wafer 1 and the second wafer 2 subjected to the alignment operation have the same diameter. The bonding cavity can be connected to a vacuum device (not shown) to evacuate the air in the bonding cavity of the wafer bonding equipment according to the requirements of the wafer bonding process, so as to form a vacuum state with a corresponding vacuum degree inside the wafer bonding equipment to meet the requirements of the wafer bonding process and avoid bubbles in the bonding surface 11.

[0090] Refer Figure 1 、 Figure 16 and Figure 17 As shown, the steps 622 respectively formed at the tops of the four support columns 6 are located on the same horizontal plane to jointly support the first wafer 1 through the four steps 622. The lengths of the column bodies 610 of the four support columns 6 are equal. Preferably, the ends 620 - 650 and the column body 610 are configured as a split structure, and the ends 620 - 650 can be replaced. The support cantilever 520 is used to isolate the second wafer 2 before it is attached to the first wafer 1. During the falling process of the second wafer 2 towards the first wafer 1, it is restricted by the four arc-shaped side walls 623 respectively formed by the ends 620 - 650 to perform the first concentricity alignment operation.

[0091] When the elastic ejector rod assembly 49 aligns the edges of the first wafer 1 and the second wafer 2 before they are attached, the first wafer 1 and the second wafer 2 are separated from each other. The gap 12 between the first wafer 1 and the second wafer 2 is greater than the thickness of the sheet-like member 521, and the gap 12 between the first wafer 1 and the second wafer 2 is less than the height formed by the ejector rod 491 along its vertical direction.

[0092] Before the first wafer 1 and the second wafer 2 are attached, the ejector rod 491 aligns the edges of the first wafer 1 and the second wafer 2. The height formed by the ejector rod 491 along the vertical direction is greater than the gap 12 of the preset distance d1 formed by isolating the first wafer 1 and the second wafer 2 by the sheet-like member 521. The height formed by the ejector rod 491 along the vertical direction covers the gap and at least partially covers the edge 110 of the first wafer 1 and the edge 220 of the second wafer 2. Refer Figure 15As shown, the push rod 491 aligns the edges of the first wafer 1 and the second wafer 2 before bonding. The height formed by the push rod 491 in the vertical direction covers the edges of the first wafer 1 and the second wafer 2 after bonding. Specifically, the height d2 formed by the abutment post 4911 in the vertical direction covers the gap 12 in the horizontal direction. This allows the abutment post 4911 to simultaneously push the edges of the first wafer 1 and the second wafer 2 during the secondary concentricity alignment of the edges of the two wafers, while also reducing the contact area formed between the abutment post 4911 and the edges of the first wafer 1 and the second wafer 2, thereby reducing scratches on the edges of the first wafer 1 and the second wafer 2.

[0093] The floating plate 70 has four guide brackets 702 arranged laterally and symmetrically with respect to the hot plate 20 and the spacer mechanism 50. The wafer bonding alignment device includes four flexible alignment components 40 adapted to the guide brackets 702, wherein two flexible alignment components 40 are symmetrically arranged on one or both sides of the spacer mechanism 50. The guide brackets 702 form rectangular through holes 712, and guide surfaces 722 are formed on the side of the rectangular through holes 712 away from the hot plate 20 and along the width direction of the rectangular through holes 712, and the guide surfaces 722 extend to the bottom of the guide brackets 702. A laterally arranged guide bracket base 7021 is formed at one end of the guide bracket 702 near the floating plate 70, and a bolt is used to laterally pass through the guide bracket base 7021 and screw it into a blind hole (not shown) with internal threads opened on the side of the floating plate 70. The flexible alignment assembly 40 includes a positioning assembly, a rolling element 42 guided by a guide surface 722, and a supporting assembly. The floating plate 70 moves up and down under the drive of the third drive mechanism 73. The rolling element 42 slides under the guidance of the guide surface 722. The positioning assembly moves radially along the limiting groove 204 (i.e., ...). Figure 9 (The horizontal direction where the bidirectional arrow R1 is located) is used to perform a second alignment (i.e., a second concentricity alignment process) on the edges of the first wafer 1 and the second wafer 2 before bonding by the positioning component.

[0094] Combination Figure 15 and Figure 16 As shown, the alignment performed by the positioning component is synchronously driven by a horizontally positioned and vertically rising floating plate 70. When the abutment post 4911 formed near the end of the bending portion 43 close to the hot plate 20 does not perform secondary alignment on the edges of the first wafer 1 and the second wafer 2, the floating plate 70 is separated from the support plate 30, and the floating plate 70 is located at the lower dead center position. When the abutment post 4911 performs secondary alignment on the edges of the first wafer 1 and the second wafer 2, the floating plate 70 moves upward in a horizontal posture under the drive of the third drive mechanism 73 and fits against the support plate 30, and the floating plate 70 is located at the upper dead center position.

[0095] Combination Figure 18 and Figure 19As shown, the process of the floating plate 70 synchronously driving four flexible alignment components 40 to perform secondary alignment of the edges of the first wafer 1 and the second wafer 2 before bonding is as follows. In this embodiment, the floating plate 70 is driven by a third driving mechanism 73. The third driving mechanism 73 includes: a third power unit 731 (e.g., a cylinder or linear motor), a fixed seat 737, a sliding seat 611, a moving block 732 driven by the third power unit 731 and moving in a vertical direction, and a track and a slider (not shown) that forms a linear motion along the track are provided between the moving block 732 and the fixed seat 607. The sliding connection technology formed by the track and the slider that forms a linear motion along the track is a mature existing technology, so it is not described in detail in this embodiment. The moving block 732 is vertically connected to the drive shaft 735, the drive shaft 735 passes through the mounting seat 734, and the mounting seat 734 and the moving block 732 are axially clamped by a bellows 733, for example, made of stainless steel, so as to prevent outside air from entering the bonding cavity and to play an auxiliary role in power transmission. The drive shaft 735 extends vertically out of the mounting base 734. The third power unit 731 forms a drive shaft (not shown) connected to the moving block 732, so as to drive the moving block 732 to move vertically by extending and retracting in the vertical direction through the drive shaft, thereby driving the floating plate 70 to move up and down through the drive shaft 735.

[0096] The process of performing two concentric alignments by the wafer bonding alignment device disclosed in this embodiment is as follows. The two concentric alignments are only a typical example and are not considered as a specific limitation of the wafer bonding process implemented by the wafer bonding equipment including the wafer bonding alignment device.

[0097] After the support column 6 is raised to a preset height, the first wafer 1 is transferred above the support column 6 by a wafer transfer arm (not shown) and supported by four ends 620-650. Bonding adhesive is then spin-coated onto the upper surface of the first wafer 1. Then, the support cantilever 520 is driven along... Figure 1 The wafer 521 rotates in the direction of arrow a, causing it to enter the circular limiting area 200. Then, the second wafer 2 continues to be transferred above the first wafer 1 via the wafer transfer arm (not shown), ensuring that the edge of the second wafer 2 is in contact with the arc-shaped sidewall 623, so that the first wafer 1 and the second wafer 2 are approximately concentrically arranged in a top-view configuration, completing the first concentricity alignment. At this point, there is a slight deviation between the concentric circles of the first wafer 1 and the second wafer 2. Then, the floating plate 70 moves upward so that the elastic push rod assembly 49, specifically included in the positioning assembly, performs a second concentricity alignment of the edges of the first wafer 1 and the second wafer 2 before bonding. After the second concentricity alignment is completed, the floating plate 70 moves downward to its lower stop point and activates a vacuum device (not shown) to evacuate the air from the bonding cavity, creating a vacuum state in the bonding cavity. Then, the support cantilever 520 moves along... Figure 1 The direction of the middle arrow b rotates and forms Figure 13 The first wafer 1 is opened and, during the synchronous opening process, the second wafer 2 falls downwards and adheres to the first wafer 1. Then, the drive support column 6 descends and preheats the adhered first wafer 1 and second wafer 2 through the recess 201 of the hot plate 20. After preheating, the support column 6 descends and supports the adhered first wafer 1 and second wafer 2 as a whole, allowing them to fall into the recess 201 formed on the surface of the hot plate 20. The two wafers are then physically bonded using a pressure plate (not shown) located in the upper cover. Finally, after the wafer bonding process is completed, the support column 6 rises to a preset height, and the two bonded wafers are removed by a wafer transfer arm (not shown), thus completing the wafer bonding process.

[0098] The wafer bonding alignment device disclosed in this embodiment can perform two concentric alignments, thereby significantly improving the concentric alignment effect of the two wafers (i.e., the first wafer 1 and the second wafer 2), eliminating the lateral error generated during the concentric alignment process using a cylinder as a power mechanism, and avoiding the formation of voids on the bonding surface 11 after the first wafer 1 and the second wafer 2 are bonded together; at the same time, the sheet-like member 521 formed by the support cantilever of the spacer mechanism 50, which opens and closes synchronously, away from the end of the first drive mechanism 51, for isolating the first wafer 1 and the second wafer 2, shortens the second The drop distance of wafer 2 during the bonding process to the first wafer 1 reduces the impact force of the second wafer 2 on the first wafer 1. At the same time, since the first wafer 1 and the second wafer 2 have not yet bonded during the secondary alignment process, wrinkles are avoided in the bonding adhesive spin-coated on the surface of the first wafer 1 during the secondary alignment process. This ensures that the bonding adhesive in the bonding surface 11 formed by the first wafer 1 and the second wafer 2 remains in a uniformly spread state, thereby ensuring the yield of the wafer bonding process.

[0099] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0100] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wafer bonding alignment device for bonding the first wafer to the second wafer. Its features are, include: The hot plate, the partition mechanism, and the alignment mechanism are provided, wherein the side of the hot plate is provided with several limiting grooves pointing to the center of the hot plate. The alignment mechanism includes a flexible alignment component, a floating plate, and a third drive mechanism. The floating plate is laterally arranged with a guide bracket, which forms a guide surface facing the hot plate. The flexible alignment component includes a positioning component, a rolling element guided by the guide surface, and a holding component. The floating plate moves up and down under the drive of the third drive mechanism, the rolling element slides under the guidance of the guide surface, and the positioning component moves radially along the limiting groove to align the edges of the first wafer and the second wafer at least before they are bonded together. The spacer mechanism is symmetrically arranged on both sides of the hot plate to periodically isolate the first wafer and the second wafer.

2. The wafer bonding alignment apparatus according to claim 1, characterized in that, The wafer bonding alignment device further includes a limiting mechanism; the limiting mechanism includes at least two support columns with arc-shaped sidewalls formed on their inner sides facing the center of the hot plate, so that the arc-shaped sidewalls together form a circular limiting area; the limiting mechanism moves vertically to the hot plate to perform alignment of the first wafer and the second wafer through the circular limiting area; the hot plate forms a recessed portion; and the limiting groove communicates with the recessed portion.

3. The wafer bonding alignment apparatus according to claim 2, characterized in that, The limiting mechanism includes: at least two support columns with tops forming ends, a support plate connected to the support columns, and a second drive mechanism that drives the support plate to move up and down in the vertical direction. The wafer bonding alignment device further includes a support plate disposed below the hot plate, and the alignment mechanism further includes four flexible alignment components symmetrically arranged relative to the center of the hot plate; the inner side of the end facing the center of the hot plate forms a step and an arc-shaped sidewall, the arc-shaped sidewall together enclose the circular limiting area, the support column continuously and vertically penetrates the hot plate and the support plate, and the flexible alignment components are fixedly disposed on the upper surface of the support plate.

4. The wafer bonding alignment apparatus according to claim 3, characterized in that, The limiting mechanism further includes: a first guide post that penetrates vertically through the support plate and the floating plate, and a first abutting base; the floating plate further includes: a second guide post that penetrates vertically through the floating plate, and a second abutting base, wherein the first abutting base and the second abutting base form abutting surfaces at the same horizontal height.

5. The wafer bonding alignment apparatus according to claim 3, characterized in that, The positioning component includes: a column, a bent portion that bends toward the hot plate, and an elastic push rod assembly, wherein the bent portion forms a receiving channel for receiving the elastic push rod assembly along its extension direction. The elastic push rod assembly includes a push rod that extends partially out of the bent portion and moves radially telescoping along the receiving channel relative to the center of the hot plate, an adjusting nut screwed into the receiving channel, and a first elastic member horizontally abutting between the adjusting nut and the push rod.

6. The wafer bonding alignment apparatus according to claim 5, characterized in that, The abutment assembly includes: a support fixed to the support plate, an abutment plate, a guide shaft that horizontally penetrates the support and is connected to the column, a second elastic element that is horizontally clamped by the abutment plate and the support and sleeved on the outside of the guide shaft, and a guide sleeve that is embedded in the support and for the guide shaft to be inserted into. The guide shaft penetrates the guide sleeve and horizontally rigidly connects the column and the abutment plate. The rolling element is provided at the bottom of the column. When the floating plate moves up and down in the vertical direction, the rolling element slides along the guide surface, the second elastic element is held against the guide sleeve and applies elastic force to the holding plate to drive the holding plate to move closer or further away from the support, so as to drive the bending part to move radially and extend and retract along the limiting groove through the guide shaft, and the first wafer and the second wafer are laterally held against each other before bonding by the top rod.

7. The wafer bonding alignment apparatus according to claim 6, characterized in that, The spacer mechanism includes: two support cantilever arms, a first drive mechanism that drives the two support cantilever arms to open and close synchronously, the ends of the support cantilever arms away from the first drive mechanism forming sheet-like parts that isolate the first wafer and the second wafer, the support cantilever arms closing synchronously to isolate the first wafer and the second wafer; during the synchronous opening of the support cantilever arms, the circular limiting area guides the second wafer to approach the first wafer and fit together with it.

8. The wafer bonding alignment apparatus according to claim 7, characterized in that, When the elastic push rod assembly aligns the edges of the first wafer and the second wafer before bonding, the gap between the first wafer and the second wafer is greater than the thickness of the sheet, and the gap between the first wafer and the second wafer is less than the height formed by the push rod in its vertical direction.

9. The wafer bonding alignment apparatus according to claim 7, characterized in that, Before the first wafer and the second wafer are bonded together, the push rod aligns the edges of the first wafer and the second wafer. The height of the push rod in the vertical direction is greater than the gap formed by the sheet separating the first wafer and the second wafer by a preset distance. The height of the push rod in the vertical direction covers the gap and at least partially covers the edges of the first wafer and the second wafer.

10. The wafer bonding alignment apparatus according to claim 7, characterized in that, The push rod aligns the edges of the first and second wafers before they are bonded together. The height formed by the push rod in the vertical direction covers the edges of the first and second wafers after they are bonded together. The first and second wafers are supported by the limiting mechanism and suspended above the recessed portion.

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