Wafer pre-bonding device

Abstract

The utility model relates to a wafer pre-bonding device. The wafer pre-bonding device comprises a vacuum chamber, a bonding platform, a supporting mechanism, an image acquisition mechanism, an XY theta alignment mechanism and an upper ejector pin lifting mechanism, the bonding platform is movably arranged in the vacuum chamber and is used for supporting the first wafer; the supporting mechanism is arranged in the vacuum chamber and is used for supporting the second wafer in the vacuum chamber; the image acquisition mechanism is arranged in the vacuum chamber and is used for acquiring morphology information and position information of the first wafer and the second wafer; the XYtheta alignment mechanism is arranged in the vacuum chamber and is connected with the bonding platform, and the XYtheta alignment mechanism is used for driving the bonding platform to move along an XY axis and rotate around a theta axis based on the morphology information and the position information of the first wafer and the second wafer, so that the first wafer and the second wafer are aligned; and the upper ejector pin lifting mechanism is arranged in the vacuum chamber and is used for pressing the second wafer downwards after the first wafer and the second wafer are aligned, so that the second wafer is bonded with the first wafer. According to the wafer pre-bonding device, rapid and accurate alignment of the wafer can be realized.

Description

Technical Field

[0001] The present application relates to the field of semiconductor preparation technology, and in particular to a wafer pre-bonding device. Background Art

[0002] With the advent of the post-Moore era, integrated circuits present the following significant characteristics: front-end manufacturing has approached the physical limit, and traditional solutions are unsustainable; at the same time, 5G communication plus the Internet of Things makes it possible to connect everything, and diversified smart terminals are widely used in smart agriculture, energy, cities and other fields. The accompanying data is growing exponentially. How to achieve efficient, low-consumption and reliable processing of massive data has become an urgent and unavoidable problem. Urgent practical needs have promoted the vigorous development of new processes and new materials. Advanced packaging has become one of the key paths to surpass Moore's Law and improve system performance. Advanced packaging faces the challenges of ultra-thin wafer thinning and holding problems, and wafer temporary bonding technology, as a core process in advanced packaging, makes it possible. When temporarily bonding wafers, the carrier wafer and the device wafer must be pre-bonded first. The device wafer has roundness error and warping possibility. In the past, when mechanical alignment was used, the center offset could only be ≤100μm, which was a large error. Summary of the invention

[0003] Based on this, it is necessary to provide a wafer pre-bonding device to address the above problems.

[0004] A wafer pre-bonding device is used for bonding a first wafer to a second wafer, the wafer pre-bonding device comprising: a vacuum chamber;

[0005] A bonding platform, movably disposed in the vacuum chamber and used for supporting the first wafer;

[0006] A supporting mechanism, disposed in the vacuum chamber and used to support the second wafer above the first wafer or release the second wafer;

[0007] An image acquisition mechanism, disposed in the vacuum chamber and used to acquire morphology information and position information of the first wafer and the second wafer;

[0008] An XYθ alignment mechanism, disposed in the vacuum chamber and connected to the bonding platform, for driving the bonding platform to move along the XY axis and rotate around the θ axis based on the morphology information and position information of the first wafer and the second wafer, so as to align the first wafer with the second wafer; and

[0009] The upper ejector pin lifting mechanism is disposed in the vacuum chamber and is used to press down the second wafer after the first wafer and the second wafer are aligned, so that the second wafer is bonded to the first wafer.

[0010] In one embodiment, the image acquisition mechanism includes at least three image acquisition units, and the image acquisition units are arranged sequentially along the circumferential direction.

[0011] In one of the embodiments, a plurality of window mirrors are provided on the top of the vacuum chamber;

[0012] The image acquisition unit includes a first mounting seat, an imaging element, a lens and a fill light; the first mounting seat is connected to the vacuum chamber and the imaging element; the fill light is connected to the first mounting seat and is located above the corresponding window mirror to emit light to the first wafer or the second wafer; the lens is arranged on the imaging element and is used to converge the light reflected from the first wafer or the second wafer and transmit the converged light to the imaging element.

[0013] In one of the embodiments, the image acquisition unit further includes a manual slide connected to the first mounting seat and the imaging element, and the manual slide is used to adjust the position height of the imaging element relative to the first wafer or the second wafer.

[0014] In one embodiment, a supporting foot cup is provided at the bottom of the XYθ alignment mechanism and is connected to the left base and the right base.

[0015] In one embodiment, the upper ejector pin lifting mechanism includes a third power member, an upper ejector pin assembly and a fourth sealing member. The third power member is located above the vacuum chamber and a first push rod capable of linear movement is provided at the output end. The first push rod is sealed and penetrates into the vacuum chamber through the fourth sealing member to lift the upper ejector pin assembly so that the upper ejector pin assembly presses down the second wafer or separates from the second wafer.

[0016] In one embodiment, the upper ejector pin lifting mechanism further includes a sensor, which is disposed between the first push rod and the upper ejector pin assembly and is used to obtain the pressure applied by the upper ejector pin assembly to the second wafer.

[0017] In one embodiment, the wafer pre-bonding device further includes a lower ejector pin lifting mechanism, and the lower ejector pin lifting mechanism includes a fourth power member, a lower ejector pin assembly and a fifth sealing member;

[0018] The fourth power member is located below the vacuum chamber and a second push rod capable of linear movement is provided at the output end. The second push rod is sealed and passed through the vacuum chamber by the fifth sealing member to lift and lower the lower ejector pin assembly so that the lower ejector pin assembly can carry the first wafer or lower the first wafer onto the bonding platform.

[0019] In one of the embodiments, a heating plate assembly is disposed on the bonding platform, and the heating plate assembly is used to support and heat the first wafer;

[0020] The heating plate assembly includes a ceramic plate, a graphite plate, a resistance wire heating plate and a thermal insulation plate which are stacked in sequence from top to bottom, the ceramic plate is used to support the first wafer, and the thermal insulation plate is connected to the bonding platform.

[0021] In one of the embodiments, a vacuum groove is disposed on the upper surface of the ceramic disk, and the vacuum groove is used to adsorb the first wafer onto the ceramic disk.

[0022] The above-mentioned wafer pre-bonding device, through the cooperation of the image acquisition mechanism 400 and the XYθ alignment mechanism 500, can realize fast and accurate alignment of the wafer, effectively avoiding the shortcomings of mechanical alignment, and can achieve the alignment accuracy requirements of center offset ≤30μm and notch ≤0.1°. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a front view of a wafer pre-bonding device provided in one embodiment of the present application.

[0024] FIG. 2 is a schematic diagram of the three-dimensional structure of a heating plate structure provided in an embodiment of the present application.

[0025] FIG3 is a schematic diagram of the working process of a wafer pre-bonding device provided in one embodiment of the present application.

[0026] 4 to 8 are schematic structural diagrams of a vacuum chamber provided in an embodiment of the present application viewed from different directions.

[0027] FIG. 9 is a schematic diagram of the three-dimensional structure of an image acquisition mechanism provided in an embodiment of the present application.

[0028] FIG. 10 is a schematic diagram of the three-dimensional structure of an XYθ alignment mechanism provided in an embodiment of the present application.

[0029] FIG. 11 is a schematic diagram of the three-dimensional structure of an upper ejector lifting mechanism provided in an embodiment of the present application.

[0030] FIG. 12 is a schematic diagram of the three-dimensional structure of a lower ejector lifting mechanism provided in an embodiment of the present application.

[0031] The reference numerals in the accompanying drawings are described as follows:

[0032] 10. Wafer pre-bonding device; 100. Vacuum chamber; 110. Window mirror; 120. Footrest; 130. Vacuum gauge; 140. Vacuum transfer valve; 150. Transparent observation window; 160. Vacuum extraction pipeline; 170. Vacuum breaking pipeline; 200. Bonding platform; 210. Heating plate assembly; 211. Ceramic plate; 2111. Vacuum groove; 2111a. Annular groove; 2111b. Linear groove; 212. Graphite plate; 213. Wire resistance heating plate; 214. Insulation plate; 215. Metal hose connector; 300. Support mechanism; 400. Image acquisition mechanism; 400a , image acquisition unit; 410, first mounting seat; 411, slide mounting seat; 412, slide adapter plate; 420, imaging element; 421, camera mounting seat; 430, lens; 440, fill light; 450, manual slide; 451, knob; 500, XYθ alignment mechanism; 510, second transmission shaft; 520, moving unit; 521, X-axis moving mechanism; 5211, base; 5212, fifth power member; 522, Y-axis moving mechanism; 5221, saddle; 5222, sixth power member; 5223, sliding seat; 523, supporting foot cup; 524 , left base; 525, right base; 526, adjusting top block; 530, rotating unit; 531, second power member; 5311, first power body; 5312, chassis; 5313, shield; 532, second seal; 533, third seal; 5331, fourth flange; 5332, fifth flange; 600, upper ejector lifting mechanism; 610, third power member; 611, first push rod; 612, first mounting plate; 620, upper ejector assembly; 621, first mounting plate; 622, first ejector; 630, fourth seal; 631, sixth method flange; 632, seventh flange; 640, sensor; 650, first guide column; 660, third mounting seat; 670, first linear bearing; 700, lower ejector lifting mechanism; 710, fourth power member; 711, second push rod; 712, second mounting plate; 713, fourth mounting seat; 720, lower ejector assembly; 721, ejector plate; 722, ejector structure; 7221, second mounting plate; 7222, second ejector; 730, fifth sealing member; 731, eighth flange; 732, ninth flange; 740, second guide column; 741, second linear bearing. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0035] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0037] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0039] Refer to Figure 1, which shows a structural schematic diagram of a wafer pre-bonding device 10 in an embodiment of the present application. The wafer pre-bonding device 10 provided in an embodiment of the present application is used for bonding a first wafer and a second wafer and includes a vacuum chamber 100, a bonding platform 200, a supporting mechanism 300, an image acquisition mechanism 400, an XYθ alignment mechanism 500 and an upper ejector pin lifting mechanism 600. Specifically, the bonding platform 200 can be movably arranged in the vacuum chamber 100 and is used to support the first wafer; the supporting mechanism 300 is arranged in the vacuum chamber 100 and is used to support the second wafer in the vacuum chamber 100; the image acquisition mechanism 400 is arranged in the vacuum chamber 100 and is used to obtain the morphology information and position information of the first wafer and the second wafer; the XYθ alignment mechanism 500 is arranged in the vacuum chamber 100 and is connected to the bonding platform 200, and the XYθ alignment mechanism 500 is used to drive the bonding platform 200 to move along the XY axis and rotate around the θ axis based on the morphology information and position information of the first wafer and the second wafer, so as to align the first wafer with the second wafer; the upper ejector lifting mechanism 600 is arranged in the vacuum chamber 100 and is used to press down the second wafer after the first wafer and the second wafer are aligned, so that the second wafer is bonded to the first wafer.

[0040] It should be noted that, in order to facilitate description of the structure in the vacuum chamber 100 , FIG. 1 shows a partial cross-section of the vacuum chamber 100 of the wafer pre-bonding device 10 .

[0041] The wafer pre-bonding device 10 can be applied to the field of wafer pre-bonding, and is used to pre-bond a device wafer (i.e., a first wafer) with a carrier wafer (i.e., a second wafer). The wafer pre-bonding device 10 can realize fast and accurate wafer alignment through the cooperation of the image acquisition mechanism 400 and the XYθ alignment mechanism 500, effectively avoiding the shortcomings of mechanical alignment, and can achieve alignment accuracy requirements of center offset ≤30μm and notch ≤0.1°.

[0042] Further, as shown in FIG. 1 , in some embodiments of the present application, the wafer pre-bonding device 10 further includes a lower ejector lifting mechanism 700, which is used to receive the first wafer and lower the first wafer to the bonding platform 200. When the external wafer robot transports the first wafer into the vacuum chamber 100, the lower ejector lifting mechanism 700 rises to receive the first wafer, and then descends to place the first wafer on the bonding platform 200, so as to realize the bonding platform 200 supporting the first wafer, which is beneficial to the subsequent alignment and bonding.

[0043] As shown in FIG1 , the bonding platform 200 is provided with a heating plate assembly 210, and the heating plate assembly 210 is used to support and heat the first wafer. During the pre-bonding process, the device wafer is always placed on the heating plate assembly 210, which can effectively avoid the deformation problem that may exist during the pre-bonding process of using the lower ejector lifting mechanism 700 to support the device wafer.

[0044] As shown in FIG2 , in some embodiments of the present application, the heating plate assembly 210 includes a ceramic plate 211, a graphite plate 212, a resistance wire heating plate 213 and a heat insulation plate 214 stacked in sequence from top to bottom, the ceramic plate 211 is used to support the first wafer, and the heat insulation plate 214 is connected to the first transmission shaft 350. Among them, the ceramic plate 211 can be made of silicon carbide, and the ceramic plate 211 is used to receive and transfer heat to the device wafer; the graphite plate 212 is used to conduct the heat generated by the resistance wire heating plate 213 to the ceramic plate 211 so that it is evenly heated; the resistance wire heating plate 213 is embedded with a heating wire to generate heat to heat the device wafer; the heat insulation plate 214 is used to block the heat generated by the resistance wire heating plate 213 to avoid direct contact with the XYθ alignment mechanism 500.

[0045] 2 , the upper surface of the ceramic plate 211 is provided with a vacuum groove 2111, and the vacuum groove 2111 is used to adsorb the first wafer onto the ceramic plate 211. When the device wafer and the carrier wafer are aligned, the vacuum groove 2111 can be evacuated, so that the device wafer can be adsorbed onto the ceramic plate 211 to prevent the device wafer from sliding.

[0046] As shown in Fig. 2, the vacuum groove 2111 includes a plurality of concentrically arranged annular grooves 2111a and a linear groove 2111b connecting the plurality of annular grooves 2111a. The outer peripheral surface of the ceramic disk 211 or the graphite disk 212 is provided with a metal hose connector 215 communicating with the linear groove 2111b, and the metal hose connector 215 is used for vacuuming and adsorbing the device wafer.

[0047] Referring to FIG. 3 , the working process of the wafer pre-bonding device 10 can be described as follows:

[0048] During the temporary wafer bonding process, the vacuum chamber 100 is first broken, and the external wafer robot absorbs the device wafer coated with bonding glue from the bottom and enters the vacuum chamber 100. The lower ejector lifting mechanism 700 rises to support the device wafer and rises to a safe distance. The external wafer robot exits the vacuum chamber 100, and the lower ejector lifting mechanism 700 descends to lower the device wafer onto the heating plate assembly 210. Then the image acquisition mechanism 400 obtains the morphology information and position information of the device wafer. The external wafer robot absorbs the carrier wafer from the top and enters the vacuum chamber 100. The external wafer robot absorbs the carrier wafer and descends to a suitable distance from the bonding glue on the upper surface of the device wafer. The support mechanism 300 then supports the carrier wafer. The wafer robot exits the vacuum chamber 100, and then the image acquisition mechanism 400 obtains the morphology information and position information of the carrier wafer. The XYθ alignment mechanism 500 performs X and Y axial translation and θ-axis rotation based on the morphology information and position information of the device wafer and the carrier wafer until the device wafer on the heating plate assembly 210 is centered and Notch aligned with the carrier wafer. The vacuum chamber 100 begins to evacuate, and the vacuum degree remains unchanged after reaching the predetermined vacuum value. The upper ejector lifting mechanism 600 slowly presses down the carrier wafer, and stops pressing down when the pressure value applied to the carrier wafer reaches the predetermined value. The center of the carrier wafer deforms and concave and just contacts the bonding glue of the device wafer. At this time, the support mechanism 300 quickly releases the carrier wafer, and the carrier wafer is fully in contact with the bonding glue of the device wafer. The upper ejector lifting mechanism 600 rises and resets. At this point, the carrier wafer and the device wafer are pre-bonded.

[0049] The structures of the various mechanisms of the wafer pre-bonding device 10 are described below:

[0050] As shown in FIG1 , a foot 120 is provided at the bottom of the vacuum chamber 100, and the foot 120 can be used to install the vacuum chamber 100 on an external frame (not shown in the drawings) by screws or other threaded parts. As shown in FIG4 , a vacuum gauge 130 is provided at the top of the vacuum chamber 100, and the vacuum gauge 130 is used to detect the vacuum degree in the vacuum chamber 100 to ensure that the device wafer and the carrier wafer are bonded at a predetermined vacuum value. The vacuum gauge 130 can be sealed and assembled on the top of the vacuum chamber 100 by matching a sealing ring with an inner ring and a clamp. As shown in FIG5 , the vacuum chamber 100 is provided with a vacuum transmission valve 140, and the vacuum transmission valve 140 is used for the transmission of the device wafer and the carrier wafer and the vacuum sealing of the vacuum chamber 100. The vacuum transmission valve 140 can be raised and lowered on the front of the vacuum chamber 100, and the vacuum can be broken in the vacuum chamber 100 when the vacuum transmission valve 140 descends, and the vacuum can be closed when the vacuum transmission valve 140 rises. Among them, the vacuum transmission valve 140 is assembled on the vacuum chamber 100 by screws and other threaded parts and calipers. As shown in Figure 6, the vacuum chamber 100 is provided with a transparent observation window 150 for observing the pre-bonding process. Among them, the transparent observation window 150 is fixed to the back of the vacuum chamber 100 through a flange. As shown in Figure 7, the vacuum chamber 100 is provided with a vacuum pumping pipe 160, and the vacuum pumping pipe 160 is used for vacuum pumping the vacuum chamber 100. Among them, the vacuum pumping pipe 160 is sealed and assembled to the bottom of the vacuum chamber 100 by screws and other threaded parts and sealing rings. As shown in Figure 8, the vacuum chamber 100 is provided with a vacuum breaking pipe 170, and the vacuum breaking pipe 170 is used to break the vacuum of the vacuum chamber 100. Among them, the vacuum breaking pipe 170 is assembled on the top of the vacuum chamber 100 through a CF-VCR conversion joint.

[0051] In some embodiments of the present application, the support mechanism 300 includes a plurality of support units, which are circumferentially arranged around the XYθ alignment mechanism 500. When the external wafer robot adsorbs the carrier wafer onto the top of the device wafer, the plurality of support units cooperate to support the carrier wafer. There are at least three support units to ensure that the carrier wafer can be stably supported.

[0052] Furthermore, the supporting unit includes a first power member, a first sealing member, a fixing member and a transmission assembly; the first power member is located outside the vacuum chamber, and the output end of the first power member is provided with a first transmission shaft that can extend into the vacuum chamber and can rotate; the first sealing member sealing sleeve is arranged on the outside of the first transmission shaft; the fixing member and the first sealing member are respectively arranged on the inner and outer surfaces of the bottom of the vacuum chamber 100, and the fixing member is provided with a slidable mounting portion, which is used to support the second wafer; the transmission assembly is located in the vacuum chamber, and is hinged with the first transmission shaft and the mounting portion, so as to drive the mounting portion to move horizontally on the fixing member when the first transmission shaft rotates.

[0053] The transmission assembly of the support unit can convert the rotation of the first transmission shaft into the translational movement of the mounting part on the fixed part, and there is no need to use the translational movement of the first transmission shaft to realize the translational movement of the mounting part. In this way, the first transmission shaft of the first power member can be vertically installed at the bottom of the vacuum chamber, and can be flexibly applied to the scene of multiple vacuum chamber combinations, which greatly increases the possibility of automation and integration of semiconductor vacuum processes. The first transmission shaft of the first power member can also use magnetic fluid seals to realize sealed transmission, and there is no need to use welded bellows to realize transmission sealing, so that the entire sealed transmission device is flexible to install and occupies less installation space.

[0054] As shown in Fig. 9, in some embodiments of the present application, the image acquisition mechanism 400 includes at least three image acquisition units 400a, and the image acquisition units 400a are arranged in sequence along the circumference. The wafer is generally circular, and multiple image acquisition units 400a are arranged along the circumference to facilitate acquisition of multiple position points of the wafer, so that the center of the wafer can be determined.

[0055] Regarding the number of image acquisition units 400a, it can be 3, 4 as shown in Figure 9, or more, as long as the center of the wafer can be accurately determined, and the embodiment of the present application does not impose any specific limitation.

[0056] Further, in some embodiments of the present application, a plurality of window mirrors 110 are provided on the top of the vacuum chamber 100 (see FIG. 8 ); and referring to FIG. 9 , the image acquisition unit 400a may include a first mounting seat 410, an imaging element 420, a lens 430 and a fill light 440; the first mounting seat 410 is connected to the vacuum chamber 100 and the imaging element 420; the fill light 440 is connected to the first mounting seat 410 and is located above the corresponding window mirror 110 to emit light to the first wafer or the second wafer; the lens 430 is provided on the imaging element 420 and is used to converge the light reflected from the first wafer or the second wafer and transmit the converged light to the imaging element 420; the imaging element 420 is used to form an image based on the converged light. The image acquisition unit 400a of this structure can improve the imaging quality and facilitate the precise alignment of the subsequent device wafer and the carrier wafer.

[0057] The imaging element 420 may be a CCD camera, and the imaging element 420, the lens 430 and the fill light 440 are coaxially arranged to improve the imaging quality.

[0058] 9, the image acquisition unit 400a further includes a manual slide 450 connected to the first mounting seat 410 and the imaging element 420, and the manual slide 450 is used to adjust the position height of the imaging element 420 relative to the first wafer or the second wafer. By operating the manual slide 450, the position height of the imaging element 420 relative to the first wafer or the second wafer can be fine-tuned to ensure that the imaging element 420 presents the best photographic effect.

[0059] As shown in FIG. 9 , a knob 451 is disposed on the side of the manual slide 450 , and the position height of the imaging element 420 can be adjusted by rotating the knob 451 .

[0060] As shown in Figure 9, the first mounting seat 410 may include a connected slide mounting seat 411 and a slide adapter plate 412, the slide adapter plate 412 is installed on the top of the vacuum chamber 100 by screws or other threaded parts, the slide mounting seat 411 is connected to the manual slide 450, and the imaging element 420 is connected to the manual slide 450 through the camera mounting seat 421.

[0061] 10 , in some embodiments of the present application, the XYθ alignment mechanism 500 includes a moving unit 520 and a rotating unit 530, the moving unit 520 is located outside the vacuum chamber 100 and is used to drive the rotating unit 530 to move along the XY axis; the rotating unit 530 includes a second power member 531, a second sealing member 532 and a third sealing member 533; the second power member 531 is connected to the moving unit 520 and an output end is provided with a second transmission shaft 510 that can rotate around the θ axis, the second transmission shaft 510 has a first end and a second end opposite to each other, and the first end of the second transmission shaft 510 extends into the vacuum chamber 100; the second sealing member 532 is connected to the second power member 531 and is sleeved on the second end of the second transmission shaft 510, so that the second transmission shaft 510 is sealed and driven on the θ axis; the third sealing member 533 is connected to the outer wall of the vacuum chamber 100 and the second power member 531 and is sleeved on the outside of the second sealing member 532, so that the second transmission shaft 510 is sealed and driven on the XY axis.

[0062] It should be noted that the X-axis and the Y-axis are arranged in the direction shown in Fig. 10. However, the θ-axis is perpendicular to the X-axis and the Y-axis.

[0063] The XYθ alignment mechanism 500 can adjust the position of the device wafer on the X-axis, Y-axis and θ-axis respectively through the moving mechanism and the rotating mechanism, so that the device has high alignment accuracy, is stable and reliable. Among them, when the XYθ alignment mechanism 500 adjusts the position of the device wafer on the X-axis, Y-axis and θ-axis, only the first end of the second transmission shaft 510 of the XYθ alignment mechanism 500 is located in the vacuum chamber 100, and the other components of the XYθ alignment mechanism 500 are located outside the vacuum chamber 100, which can reduce the space occupied by the XYθ alignment mechanism 500 in the vacuum chamber 100, reduce the volume of the vacuum chamber 100, shorten the vacuum pumping time, and these external components can be selected at room temperature and pressure. The usable structural parts can reduce the cost of the XYθ alignment mechanism 500; in addition, the XYθ alignment mechanism 500 also adopts a second sealing member 532 of a sealing type such as magnetic fluid to ensure the sealed transmission of the second transmission shaft 510 on the θ axis and adopts a third sealing member 533 of a sealing type such as a welded bellows to ensure the sealed transmission of the second transmission shaft 510 on the X and Y axes, so that the XYθ alignment mechanism 500 can be installed and reliably docked with the vacuum chamber 100, thereby ensuring the negative pressure of the vacuum chamber 100.

[0064] The second seal 532 is a magnetic fluid type seal, and the third seal 533 is a welded bellows type seal.

[0065] In some embodiments of the present application, as shown in Figure 10, the moving unit 520 includes an X-axis moving mechanism 521 and a Y-axis moving mechanism 522; the X-axis moving mechanism 521 includes a base 5211 and a fifth power member 5212, the fifth power member 5212 is arranged on the base 5211 and is used to drive the Y-axis moving mechanism 522 to move along the X-axis on the base 5211; the Y-axis moving mechanism 522 includes a saddle 5221, a sixth power member 5222 and a sliding seat 5223, the saddle 5221 is slidably arranged on the base 5211, the sixth power member 5222 is arranged on the saddle 5221 and is used to drive the sliding seat 5223 to move along the Y-axis on the saddle 5221, and the sliding seat 5223 is connected to the second power member 531. The fifth power component 5212 of the X-axis moving mechanism 521 can drive the Y-axis moving mechanism 522 and the rotating mechanism on the Y-axis moving mechanism 522 to move along the X-axis on the base 5211, thereby adjusting the position of the rotating mechanism and the second transmission shaft 510 on the rotating mechanism on the X-axis; the sixth power component 5222 of the Y-axis moving mechanism 522 can drive the sliding seat 5223 and the rotating mechanism on the sliding seat 5223 to move along the Y-axis on the saddle 5221, thereby adjusting the position of the rotating mechanism and the second transmission shaft 510 on the rotating mechanism on the Y-axis.

[0066] Continuing to refer to FIG. 10 , the base 5211 is provided with a supporting foot cup 523 to be installed on the installation platform; and is connected to the left base base 524 and the right base base 525 by adjusting screws and other threaded parts to adjust the horizontality. When the XYθ axis alignment mechanism needs to be maintained, the left base base 524 and the right base base 525 can be removed by adjusting the adjusting bolts, and then the installation height of the foot cup 523 can be lowered, and the XYθ axis alignment mechanism can be lowered as a whole to achieve quick maintenance. Among them, referring to FIG. 10 , an adjusting top block 526 is provided between the left base base 524 and the base 5211, and between the right base base 525 and the base 5211. The adjusting top block 526 is used to fix the left base base 524 and the right base base 525 and fine-tune the relative position between the left base base 524 and the base 5211, and between the right base base 525 and the base 5211.

[0067] The number of the supporting foot cups 523 may be set according to the structure of the base 5211 . For example, if the base 5211 is substantially a hexahedron, a supporting foot cup 523 may be set at each of the four corners of the base 5211 .

[0068] As shown in FIG. 11 , in some embodiments of the present application, the upper ejector pin lifting mechanism 600 includes a third power member 610, an upper ejector pin assembly 620 and a fourth sealing member 630; the third power member 610 is located above the vacuum chamber 100 and is provided with a first push rod 611 that can move linearly at the output end, and the first push rod 611 is sealed and penetrated into the vacuum chamber 100 through the fourth sealing member 630 to lift and lower the upper ejector pin assembly 620, so that the upper ejector pin assembly 620 presses down the second wafer or separates from the second wafer. When the device wafer and the carrier wafer are aligned, the third power member 610 pushes down the upper ejector pin assembly 620 through the first push rod 611 to press down the carrier wafer, so that the carrier wafer is deformed and contacts the device wafer, and after the carrier wafer and the device wafer bonding adhesive are fully contacted, the upper ejector pin assembly 620 rises and resets under the control of the third power member 610, and the carrier wafer and the device wafer are pre-bonded.

[0069] The third power member 610 may be an electric cylinder or a hydraulic cylinder, the piston rod of which is retractable, and a first mounting plate 612 is provided on the output side of the piston rod, and the first mounting plate 612 is connected to the first push rod 611 and the fourth sealing member 630 .

[0070] The fourth sealing member 630 may be a welding bellows type sealing member, which is sleeved on the first push rod 611. As shown in FIG11 , the fourth sealing member 630 is provided with a sixth flange 631 and a seventh flange 632 at both axial ends thereof, and the sixth flange 631 may be mounted on the top wall of the vacuum chamber by screws or other threaded members, and the seventh flange 632 may also be connected to the first mounting plate 612 on the third power member 610 by screws or other threaded members.

[0071] 11 , the upper ejector assembly 620 includes a first mounting plate 621 and a plurality of first ejector pins 622 circumferentially arranged on the first mounting plate 621, and the first mounting plate 621 is connected to the first push rod 611. The number of the first ejector pins 622 may be 2, 3 as shown in FIG. 11 , or more.

[0072] Continuing to refer to FIG. 11 , the upper ejector pin lifting mechanism 600 further includes a first guide assembly, which is disposed on the top wall of the vacuum chamber 100 and includes a plurality of first guide posts 650 spaced apart in the circumferential direction, and a first mounting plate 621 is slidably disposed on the first guide posts 650 to directional lift the upper ejector pin assembly 620. The bottom of the first guide post 650 can be disposed on the top wall of the vacuum chamber 100 by means of a screw or other threaded member, and the top is connected to the housing of the third power member 610 through a third mounting seat 660. It is understandable that the third mounting seat 660 has a through hole for the piston of the third power member 610 to pass through.

[0073] In order to facilitate the sliding of the upper ejector assembly 620 , as shown in FIG. 11 , the first mounting plate 612 is provided with a first linear bearing 670 , and the first linear bearing 670 can slide along the first guide column 650 .

[0074] Continuing to refer to FIG. 11 , the upper ejector lifting mechanism 600 also includes a sensor 640, which is arranged between the first push rod 611 and the upper ejector assembly 620, and is used to obtain the pressure applied by the upper ejector assembly 620 to the second wafer. When the upper ejector assembly 620 presses down the carrier wafer, the sensor 640 monitors the pressure provided by the upper ejector assembly 620 to the carrier wafer in real time. Once the pressure reaches a predetermined pressure value, the upper ejector assembly 620 stops applying pressure to the carrier wafer. At this time, the center of the carrier wafer is deformed and concave and just contacts the bonding glue of the device wafer, and the wafer bottom support plate 332 of the support mechanism 300 also retracts quickly. The sensor 640 can ensure that the upper ejector assembly 620 will not produce overpressure behavior on the carrier wafer to protect the carrier wafer. Among them, the sensor 640 can be a pressure sensor.

[0075] As shown in FIG. 12 , in some embodiments of the present application, the lower ejector pin lifting mechanism 700 includes a fourth power member 710, a lower ejector pin assembly 720 and a fifth sealing member 730; the fourth power member 710 is located below the vacuum chamber 100 and a second push rod 711 capable of linear motion is provided at the output end, and the second push rod 711 is sealed and penetrated into the vacuum chamber 100 through the fifth sealing member 730 to lift the lower ejector pin assembly 720, so that the lower ejector pin assembly 720 can support the first wafer or lower the first wafer onto the bonding platform 200.

[0076] When the robot transports the device wafer to the interior of the vacuum chamber 100, the fourth power member 710 pushes the lower ejector pin assembly 720 upward through the second push rod 711 until the device wafer is received; thereafter, the lower ejector pin assembly 720 descends until the device wafer is placed on the bonding platform 200, and then the device wafer is aligned.

[0077] The fourth power member 710 may be an electric cylinder or a hydraulic cylinder, the piston rod of which is retractable, and a second mounting plate 712 is provided on the output side of the piston rod. The second mounting plate 712 is connected to the second push rod 711 and the fifth sealing member 730 .

[0078] The fifth sealing member 730 may be a welding bellows type sealing member, which is sleeved on the second push rod 711. As shown in FIG12 , the fifth sealing member 730 is provided with an eighth flange 731 and a ninth flange 732 at both axial ends thereof, and the eighth flange 731 may be mounted on the outer wall of the bottom of the vacuum chamber 100 by screws or other threaded members, and the ninth flange 732 may also be connected to the second mounting plate on the fourth power member 710 by screws or other threaded members.

[0079] In some embodiments of the present application, the bonding platform 200 has a plurality of ejector pin through holes; as shown in FIG. 12 , the lower ejector pin assembly 720 includes an ejector plate 721 and an ejector pin structure 722, the ejector plate 721 is connected to the second push rod 711, the lower ejector pin structure 722 includes a second mounting disk 7221 and a plurality of second ejector pins 7222, the second mounting disk 7221 is sleeved on the first end of the second transmission shaft 510, the second ejector pins 7222 extend from the side of the second mounting disk 7221 away from the ejector plate 721 and are movably inserted into the corresponding ejector pin through holes, and the second ejector pins 7222 are interference fit with the bonding platform 200 so that the lower ejector pin structure 722 and the second transmission shaft 510 move synchronously. The lower ejector pin lifting mechanism 700 is arranged in this way, so that the lower ejector pin assembly 720 can receive the device wafer and lower the device wafer to the bonding platform 200 on the second transmission shaft 510; in addition, after the second ejector pin 7222 lowers the device wafer to the bonding platform 200 on the second transmission shaft 510, the second ejector pin 7222 does not need to continue to descend to separate from the top plate 721, and can move with the second transmission shaft 510 without hindering the second transmission shaft 510 from adjusting the position of the device wafer, which can make the structure of the alignment device more compact and make the alignment device occupy less space in the vacuum chamber 100. At this time, the housing of the fourth power member 710 can be installed on the side of the base 5211 of the X-axis moving mechanism 521 through the fourth mounting seat 713 shown in FIG. 12.

[0080] A guide sleeve (e.g., a ceramic guide sleeve) matching with the second ejector pin 7222 is disposed in the ejector pin through hole of the bonding platform 200. The second ejector pin 7222 can be mounted on the mounting plate by a threaded member such as a bolt, wherein a flexible washer is disposed on the screw of the threaded member. It is understood that the heating plate assembly 210 also has a plurality of through holes, which correspond one-to-one to the ejector pin through holes on the bonding platform 200, so that the second ejector pin 7222 passes through the bonding platform 200 and the heating plate assembly 210 to receive the device wafer.

[0081] Continuing to refer to FIG. 12 , the ejector lifting mechanism further includes a second guide assembly, which is disposed on the inner wall of the vacuum chamber 100 and includes a plurality of second guide posts 740 spaced apart along the circumferential direction. The ejector plate 721 of the lower ejector assembly 720 is slidably disposed on the second guide posts 740 to enable the lower ejector assembly 720 to be lifted and lowered in a directional manner.

[0082] In order to facilitate the sliding of the lower ejector assembly 720, a second linear bearing 741 is provided on the ejector plate 721, and the second linear bearing 741 can slide along the second guide column 740. The second linear bearing 741 is a vacuum linear bearing.

[0083] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A wafer pre-bonding device, characterized in that: Used for pre-bonding of a first wafer and a second wafer, the wafer pre-bonding device comprises: a vacuum chamber; A bonding platform, movably disposed in the vacuum chamber and used for supporting the first wafer; A supporting mechanism, disposed in the vacuum chamber and used to support the second wafer above the first wafer or release the second wafer; An image acquisition mechanism, disposed in the vacuum chamber and used to acquire morphology information and position information of the first wafer and the second wafer; An XYθ alignment mechanism, disposed in the vacuum chamber and connected to the bonding platform, for driving the bonding platform to move along the XY axis and rotate around the θ axis based on the morphology information and position information of the first wafer and the second wafer, so as to align the first wafer with the second wafer; and The upper ejector pin lifting mechanism is disposed in the vacuum chamber and is used to press down the second wafer after the first wafer and the second wafer are aligned, so that the second wafer is bonded to the first wafer.

2. The wafer pre-bonding device according to claim 1, characterized in that: The image acquisition mechanism includes at least three image acquisition units, and the image acquisition units are arranged in sequence along the circumference of the bonding platform.

3. The wafer pre-bonding device according to claim 2, characterized in that: A plurality of window mirrors are arranged on the top of the vacuum chamber; The image acquisition unit includes a first mounting seat, an imaging element, a lens and a fill light; the first mounting seat is connected to the vacuum chamber and the imaging element; the fill light is connected to the first mounting seat and is located above the corresponding window mirror to emit light to the first wafer or the second wafer; the lens is arranged on the imaging element and is used to converge the light reflected from the first wafer or the second wafer and transmit the converged light to the imaging element.

4. The wafer pre-bonding device according to claim 3, characterized in that: The image acquisition unit further includes a manual slide connected to the first mounting seat and the imaging element, and the manual slide is used to adjust the position height of the imaging element relative to the first wafer or the second wafer.

5. The wafer pre-bonding device according to claim 1, characterized in that: The bottom of the XYθ alignment mechanism is provided with a supporting foot cup and is top-connected to the left base and the right base.

6. The wafer pre-bonding device according to claim 1, characterized in that: The upper ejector pin lifting mechanism includes a third power member, an upper ejector pin assembly and a fourth sealing member. The third power member is located above the vacuum chamber and a first push rod capable of linear movement is provided at an output end thereof. The first push rod is sealed and penetrates into the vacuum chamber through the fourth sealing member to lift the upper ejector pin assembly so that the upper ejector pin assembly presses down the second wafer or separates from the second wafer.

7. The wafer pre-bonding device according to claim 6, characterized in that: The upper ejector pin lifting mechanism further includes a sensor, which is disposed between the first push rod and the upper ejector pin assembly and is used to obtain the pressure applied by the upper ejector pin assembly to the second wafer.

8. The wafer pre-bonding device according to any one of claims 1 to 7, characterized in that: The wafer pre-bonding device further includes a lower ejector pin lifting mechanism, wherein the lower ejector pin lifting mechanism includes a fourth power member, a lower ejector pin assembly and a fifth sealing member; The fourth power member is located below the vacuum chamber and a second push rod capable of linear movement is provided at the output end. The second push rod is sealed and passed through the vacuum chamber by the fifth sealing member to lift and lower the lower ejector pin assembly so that the lower ejector pin assembly can carry the first wafer or lower the first wafer onto the bonding platform.

9. The wafer pre-bonding device according to any one of claims 1 to 7, characterized in that: A heating plate assembly is arranged on the bonding platform, and the heating plate assembly is used to support and heat the first wafer; The heating plate assembly includes a ceramic plate, a graphite plate, a resistance wire heating plate and a thermal insulation plate which are stacked in sequence from top to bottom, the ceramic plate is used to support the first wafer, and the thermal insulation plate is connected to the bonding platform.

10. The wafer pre-bonding device according to claim 9, characterized in that: A vacuum groove is provided on the upper surface of the ceramic disk, and the vacuum groove is used to adsorb the first wafer onto the ceramic disk.

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