Wafer bonding equipment and method

Abstract

The invention discloses wafer bonding equipment and a wafer bonding method. The wafer bonding equipment comprises an air bag device for pressing a wafer, the airbag device comprises a mounting frame, a floating mechanism, a fixing frame and an airbag which are sequentially arranged up and down; the air bag is installed below the fixing frame, and the fixing frame is rotationally connected with the installation frame through a floating mechanism. The floating mechanism comprises a ball bearing and a plurality of supporting rods, two ends of the ball bearing are connected to the middle of the fixing frame and the middle of the mounting frame respectively, the supporting rods are circumferentially distributed on the periphery of the ball bearing at intervals, the lower ends of the supporting rods are fixedly connected to the fixing frame, and the upper ends of the supporting rods movably penetrate through movable holes formed in the mounting frame. Therefore, through the arrangement of the floating mechanism, when the air bag presses the wafers downwards in the wafer bonding process, the air bag can swing freely within a certain range through the rotary connection of the ball bearing and the limiting of the supporting rods, the effect of removing bubbles in the two wafers from the middle to the outside can be achieved, it is ensured that the two wafers are bonded tightly, and the bonding quality of the wafers is improved. And the bonding strength and precision are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor production, and in particular to a wafer bonding device and method. Background Art Wafer bonding technology refers to the process of tightly combining two mirror-polished homogeneous or heterogeneous wafers through chemical and physical effects. After the wafers are bonded, the atoms on the interface react under the action of external forces to form covalent bonds to combine them into one, and the bonding interface reaches a specific bonding strength.

[0002] The use of bonding technology can effectively solve the problems of lattice mismatch and flatness. This requires that the difference in surface flatness and elastic modulus of the two bonded wafers is small; the surface required for bonding needs to be very smooth, and the surface roughness requirement is very high. In the existing technology, two wafers are usually placed in a wafer bonding device, and a pressure head is used to apply pressure to the two bonded wafers to make the two tightly bonded; the pressure head is generally made of graphite, but the graphite pressure head is relatively hard, which will have a certain impact on the wafer bonding, so some pressure heads use flexible pressure heads made of airbags to improve the extrusion effect; however, in the production process, wafers are often reused, and the wafers are warped, resulting in the existing straight up and down airbags for pressing. There are still defects such as loose bonding, misalignment of the two wafers, and residual bubbles between wafers, which affect the bonding strength and accuracy.

[0003] In order to overcome the above shortcomings, the inventors have specially invented a wafer bonding device and method, from which this case is derived. Summary of the invention

[0004] The object of the present invention is to provide a wafer bonding device and method, which can solve the above-mentioned defects and have the advantage of ensuring bonding tightness.

[0005] In order to achieve the above object, the solution of the present invention is: A wafer bonding device comprises an airbag device for pressing wafers; the airbag device comprises a mounting frame, a floating mechanism, a fixed frame and an airbag which are arranged in sequence up and down; the airbag is installed below the fixed frame, and the fixed frame and the mounting frame are rotatably connected through the floating mechanism; the floating mechanism comprises a ball bearing and a plurality of support rods, the two ends of the ball bearing are respectively connected to the middle of the fixed frame and the middle of the mounting frame, the support rods are respectively distributed on the outer periphery of the ball bearing at circumferential intervals, the lower ends of the support rods are connected and fixed to the fixed frame, and the upper ends of the support rods are movably inserted into movable holes provided on the mounting frame.

[0006] Furthermore, a fixing groove is provided in the middle of the fixing frame, a fixing rod is horizontally arranged in the fixing groove, the bearing portion of the ball bearing is passed through by the fixing rod and can rotate freely in the fixing groove, and the connecting rod portion of the ball bearing is connected and fixed to the mounting frame.

[0007] Furthermore, the movable hole is a countersunk hole arranged on the upper side of the mounting frame, and the countersunk hole passes through the bottom surface of the mounting frame; the support rods have four pieces, all of which are bolts, the heads of the bolts are accommodated in the movable holes, and the rods of the bolts pass downward through the movable holes and are locked and fixed with the fixing holes set on the fixing frame.

[0008] Furthermore, an airbag mounting plate is provided below the fixing frame; the airbag mounting plate comprises an upper support plate and a lower support plate which are arranged up and down, and the upper part of the airbag is clamped and fixed by the upper support plate and the lower support plate; the lower support plate is annular, and the lower part of the airbag after inflation can expand downward from the annular hole of the lower support plate to form an arc bulge.

[0009] Furthermore, a sensor mounting plate and a plurality of pressure sensors are provided between the airbag mounting plate and the fixing frame; the sensor mounting plate is connected to the top of the fixed airbag mounting plate, and the pressure sensors are distributed at intervals in the central circumferential direction of the fixing frame; the fixing frame and the sensor mounting plate are both disc-shaped, the outer diameter of the fixing frame is smaller than the outer diameter of the sensor mounting plate, the inner end upper side of the pressure sensor is connected to the bottom of the fixing frame, and the outer end lower side of the pressure sensor is connected to the top of the sensor mounting plate.

[0010] Furthermore, an upper groove penetrating from top to bottom is provided on the sensor mounting plate between adjacent pressure sensors, and the upper part of the airbag has a plurality of air nozzles extending out of the upper support plate and located in the upper groove.

[0011] Furthermore, it also includes a frame, a machine table, a heating device, a lifting suction cup and a centering device; The frame and the machine platform are arranged adjacent to each other, a vertical linear module is installed on the frame, the airbag device is installed on the vertical linear module, the airbag device is suspended above the machine platform, and a pressure sensor is also arranged on the airbag device; The machine platform is provided with a wafer stage, and the wafer stage is provided with the heating device; the lifting suction cup can be lifted and lowered in the middle stage through hole of the wafer stage; the centering device is installed on the machine platform and includes two symmetrically arranged clamping claws, which can reciprocate along the radial direction of the wafer stage to approach or move away from the wafer stage, and are used to relatively abut against the edge of the wafer; The centering device also includes a notch alignment device; each clamp includes two clamp abutment portions arranged at intervals, and the notch alignment device is arranged between the two clamp abutment portions of one clamp, and the notch alignment device includes a protrusion for movably engaging and extending into the notch of the wafer; the protrusion and the clamp abutment tops on both sides are circumferentially spaced.

[0012] Furthermore, a lifting drive device and a centering drive device are installed below the wafer stage of the machine; The centering drive device comprises a centering cylinder, two clamping jaw fixing seats, two clamping jaw sliding seats and two clamping jaw cylinders; the centering cylinder is centrally located on the machine base below the center of the wafer stage, and both ends of the centering cylinder respectively have power output ends that move along the radial direction of the wafer stage, and the power output ends are respectively connected to one of the clamping jaw fixing seats, and the clamping jaw fixing seats are slidably connected to the machine base at the same time; the clamping jaw sliding seat is slidably connected to the clamping jaw fixing seat, the clamping jaw cylinder is installed on the clamping jaw fixing seat, and the clamping jaw cylinder drives the clamping jaw sliding seat to slide back and forth on the clamping jaw fixing seat; the clamping jaw is installed on the clamping jaw sliding seat; The lifting drive device includes a lifting cylinder arranged on one side of the centering cylinder, the lifting cylinder drives the suction cup bracket to move up and down, one end of the suction cup bracket is located below the wafer carrier and above the centering cylinder, and the lifting suction cup is installed, and the lifting suction cup is a vacuum suction cup.

[0013] Furthermore, a detection through hole is provided on the wafer carrier, and a wafer detection sensor is provided below the detection through hole.

[0014] The present invention also provides a wafer bonding method, which uses the wafer bonding device described above and comprises the following steps: Step 1: Preliminary preparation: the airbag device, lifting suction cup and centering device are reset, and the heating device heats and keeps the wafer stage warm; Step 2: Wafer loading; the lifting suction cup is raised from the middle of the wafer stage, and two wafers to be bonded are stacked on the lifting suction cup in sequence, and the notch openings of the two wafers are kept initially aligned, and at the same time, they are aligned toward the protrusion of the notch opening alignment device; the lifting suction cup is controlled to absorb the wafer, and after the wafer is driven to descend to the wafer stage, the absorption of the lifting suction cup is disconnected, so that the wafer is placed flat on the wafer stage; Step 3: Wafer centering: The centering device centers the wafer, and the two clamping claws relatively approach the wafer stage along the radial direction of the wafer stage and abut against the edges of the wafers to align the edges of the two wafers. At the same time, the protrusion of the notch alignment device gradually embeds into the notch of the two wafers to be bonded as the clamping claws move, so that the two wafers can be further accurately aligned. Step 4: Wafer bonding; inflate and pressurize the airbag of the airbag device, and at the same time, the vertical linear module drives the airbag device to descend. After the airbag descends and contacts the upper wafer, the floating mechanism is used to enable the continuously inflated airbag to adaptively level and cling to the upper wafer. At the same time, the bonding pressure is fed back in real time through the pressure sensor during the process of the vertical linear module driving the airbag device to descend. When the bonding pressure reaches the first pressure value, the inflation is stopped, and the clamping claws of the centering device are controlled to reset and detach from the wafer; then the vertical linear module continues to drive the airbag device downward to further pressurize the two wafers, and when the bonding pressure reaches the second pressure value, the vertical linear module is controlled to stop to maintain pressure, and the duration of the first pressure period is maintained; after the pressure maintenance is completed, the vertical linear module drives the airbag device to reset, and then the airbag is exhausted; Step 5: Unloading the bonding sheet; the lifting suction cup rises, lifts up the bonding sheet formed by the two wafers bonded on the wafer carrier, and then takes away the bonding sheet.

[0015] After adopting the technical solution of the above-mentioned equipment, the airbag of the present invention is connected to the fixing frame, and the fixing frame is connected through a floating mechanism. Therefore, in the wafer bonding process, the airbag is first inflated, and the airbag is abutted against the upper wafer during the inflation process, so that the airbag can be automatically leveled according to the flatness of the wafer by means of the rotating connection of the ball bearing and the limiting of each support rod, ensuring that the inflated airbag can be tightly attached to the upper wafer as a whole, so as to prevent the two wafers from having different flatnesses and being locally compressed and causing misalignment during the bonding process; and the provision of the airbag can achieve the effect of removing bubbles in the two wafers from the middle to the outside, ensuring that the two wafers are tightly bonded, no bubbles remain between the wafers, improving the bonding strength and accuracy, and greatly improving the bonding success rate.

[0016] After adopting the technical solution of the above method, the present invention can automatically align the two wafers through the centering device, and use the lifting suction cup for adsorption to ensure that the wafers are not misaligned; an airbag device is also provided, and the airbag has an adaptive leveling function, and the airbag device is attached with a pressure sensor, and the pressing force is controllable to ensure the tightness of the bonding. When bonding, the present invention can remove the bubbles in the two wafers from the middle to the outside to ensure that no bubbles are generated when the wafers are bonded. At the same time, the bonding force and stroke of the wafers are controllable, and the airbag device has a pressure-maintaining function to realize the wafer leveling function, and can achieve stable bonding for warped wafers, which can effectively improve the flatness of the bonding sheet and the bonding yield. And compared with the prior art, the present invention has the following advantages: ① The overall structure of the present invention is compact, occupies a small area, and can be automated; ② The present invention can center and bond wafers; ③ The present invention can realize controllable wafer bonding force and stroke; ④ The airbag of the present invention is inflated into an arc shape, and bubbles in the two wafers can be removed from the middle to the outside during bonding, ensuring that no bubbles are generated during wafer bonding; ⑤ The airbag of the present invention has a pressure-maintaining function, realizes the wafer leveling function, and can achieve stable bonding for warped wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A three-dimensional diagram of an embodiment of the present invention; Figure 2 It is a three-dimensional diagram of an airbag device according to an embodiment of the present invention, with the outer cover of the airbag device hidden; Figure 3 for Figure 2 A three-dimensional view with the top cover of the airbag device removed; Figure 4 for Figure 3 A perspective view without the mounting bracket; Figure 5 A three-dimensional view of an airbag and an airbag mounting plate of an airbag device according to an embodiment of the present invention; Figure 6 A partial structural perspective view of an embodiment of the present invention; Figure 7 for Figure 6 A three-dimensional image with the machine cover removed; Figure 8 A three-dimensional diagram of a lifting suction cup and a lifting drive device according to an embodiment of the present invention; Fig. 9 A three-dimensional diagram of a centering device and a centering drive device according to an embodiment of the present invention; Fig.10 is a flow chart of a method according to an embodiment of the present invention; Fig.11 It is a three-dimensional diagram from another angle of an embodiment of the present invention.

[0018] Description of reference numerals: Wafer 1; Airbag device 100, mounting frame 110, movable hole 111, floating mechanism 120, ball bearing 121, support rod 122, bearing portion 123, connecting rod portion 124, fixing frame 130, fixing groove 131, fixing rod 132, fixing hole 133, airbag 140, air nozzle 141, airbag device top cover 150, airbag device outer cover 160, airbag mounting plate 170, upper support plate 171, lower support plate 172, sensor mounting plate 180, pressure sensor 181, inner end upper side 182, outer end lower side 183, upper groove 184; Rack 200; Machine 300, wafer carrier 310, carrier through hole 311, detection through hole 312, wafer detection sensor 313, detection light 314, machine cover 320, machine base 330, base support 331; Lifting suction cup 400; Centering device 500, clamping jaw 510, clamping jaw abutment portion 511, notch alignment device 520, protrusion 521; Lifting drive device 600, lifting cylinder 610, suction cup support 620; Centering drive device 700, centering cylinder 710, power output end 711, clamping jaw fixing seat 720, clamping jaw sliding seat 730, clamping jaw cylinder 740; Vertical linear module 800; Control device 900, display component 910. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] like Figures 1 to 9 As shown, a wafer bonding device of this embodiment includes an airbag device 100 for pressing a wafer 1, as well as a frame 200, a platform 300, a heating device (not shown), a lifting suction cup 400, a centering device 500, a lifting drive device 600, a centering drive device 700, a vertical linear module 800 and a control device 900.

[0021] For example Figures 2 to 5 The airbag device 100 includes a mounting frame 110, a floating mechanism 120, a fixed frame 130 and an airbag 140 which are sequentially arranged up and down; the airbag 140 is installed below the fixed frame 130, and the fixed frame 130 and the mounting frame 110 are rotatably connected through the floating mechanism 120; the floating mechanism 120 includes a ball bearing 121 and a plurality of support rods 122, the two ends of the ball bearing 121 are respectively connected to the middle of the fixed frame 130 and the middle of the mounting frame 110, and the support rods 122 are respectively distributed on the outer periphery of the ball bearing 121 at circumferential intervals, the lower ends of the support rods 122 are connected and fixed to the fixed frame 130, and the upper ends of the support rods 122 are movably penetrated through the movable holes 111 provided on the mounting frame 110.

[0022] Hereby, the airbag 140 of the present embodiment is connected to the fixing frame 130, and the fixing frame 130 is connected via the floating mechanism 120. Thus, during the wafer bonding process, when the airbag 140 presses down on the wafer 1, the airbag 140 can swing freely within a certain range by virtue of the rotation connection of the ball bearing 121 and the limiting of each support rod 122, thereby realizing an adaptive leveling function and the effect of removing the bubbles in the two wafers 1 from the middle to the outside, thereby ensuring that the two wafers 1 are tightly bonded, and no bubbles remain between the wafers, thereby improving the bonding strength and accuracy, and greatly improving the bonding success rate.

[0023] More specifically, since the two wafers 1 have different flatnesses and cannot be completely consistent, one side may be uneven when the two wafers 1 are stacked, and the airbag 140 of the airbag device 100 can be pre-inflated to initially press against the upper wafer 1, and since a ball bearing 121 is provided, the airbag 140 can be adaptively rotated and leveled according to the flatness of the wafer 1 during the subsequent continuous inflation process, so that the airbag 140 presses the wafer 1 as a whole after the inflation is completed, ensuring that the wafer 1 is subjected to force as a whole when it is pressed, and the upper wafer 1 will not be locally stressed and misaligned with the lower wafer 1, thereby realizing an adaptive leveling function to ensure that the two wafers 1 have high flatness.

[0024] Specifically, Figure 1 and Figure 2 As shown, the periphery of the mounting frame 110, the floating mechanism 120 and the fixing frame 130 may be surrounded by an airbag device top cover 150 and an airbag device outer cover 160 to protect the internal structure.

[0025] Another example Figure 4 The fixing frame 130 may be provided with a fixing groove 131 in the middle, a fixing rod 132 is arranged in the fixing groove 131, and both ends of the fixing rod 132 may be locked and fixed to both sides of the fixing groove 131. The bearing portion 123 of the ball bearing 121 allows the fixing rod 132 to pass through and can rotate freely in the fixing groove 131. The connecting rod portion 124 of the ball bearing 121 is connected and fixed to the mounting frame 110. Thus, the airbag 140, the fixing frame 130 and the fixing rod 132 can rotate freely in coordination with the bearing portion 123, and the assembly operation is also convenient.

[0026] See also Figure 3, the movable hole 111 can be a countersunk hole set on the upper side of the mounting frame 110, and the countersunk hole passes through the bottom surface of the mounting frame 110; and the support rods 122 can have four pieces, all of which are bolts, and the heads of the bolts are accommodated in the movable holes 111, and the rods of the bolts pass downward through the movable holes 111 and are locked and fixed with the fixing holes 133 set on the fixing frame 130. In this way, after the ball bearing 121 rotates and connects the fixing frame 130 and the mounting frame 110, the bolts can be quickly installed, and the heads of the bolts can swing in the movable holes 111. Therefore, the support rods 122 formed by the bolts can limit the swing amplitude of the airbag 140 and the fixing frame 130 without making them unable to swing, so as to ensure the pressing effect of the airbag 140.

[0027] Another example Figure 4 and Figure 5 As shown, an airbag mounting plate 170 may be provided below the fixing frame 130; the airbag mounting plate 170 includes an upper support plate 171 and a lower support plate 172 arranged up and down, and the upper part of the airbag 140 is clamped and fixed by the upper support plate 171 and the lower support plate 172; the lower support plate 172 is annular, and the lower part of the airbag 140 after being inflated can expand downward from the annular hole of the lower support plate 172 to form an arc bulge.

[0028] In addition, a sensor mounting plate 180 and a plurality of pressure sensors 181 may be provided between the airbag mounting plate 170 and the fixing frame 130 .

[0029] The sensor mounting plate 180 is connected to the top of the fixed airbag mounting plate 170, and the pressure sensors 181 are distributed at intervals in the central circumferential direction of the fixing frame 130; the fixing frame 130 and the sensor mounting plate 180 are both disc-shaped, and the outer diameter of the fixing frame 130 is smaller than the outer diameter of the sensor mounting plate 180. The inner end upper side 182 of the pressure sensor 181 is connected to the bottom of the fixing frame 130, and the outer end lower side 183 of the pressure sensor 181 is connected to the top of the sensor mounting plate 180.

[0030] The pressure sensors 181 are provided to detect the pressure of the airbag 140 in real time during the process of pressing down the wafer 1 for bonding, so as to achieve a good bonding effect.

[0031] In order to facilitate the inflation and deflation of the airbag 140, an upper groove 184 is provided between adjacent pressure sensors 181 on the sensor mounting plate 180 of this embodiment, and the upper part of the airbag 140 has a plurality of air nozzles 141 extending out of the upper support plate 171 and located in the upper groove 184. Each air nozzle 141 can be connected to an external device (not shown) to inflate or deflate the airbag 140.

[0032] For example Figure 1 , Figures 6 to 9As shown, the rack 200 and the platform 300 of this embodiment are arranged adjacent to each other.

[0033] The frame 200 is provided with a vertical linear module 800 and a control device 900. The airbag device 100 is installed on the vertical linear module 800. The airbag device 100 is suspended above the machine table 300. The vertical linear module 800 is used to control the airbag device 100 to move up and down to press the wafer 1. The control device 900 is used to control the operation of the airbag device 100, the vertical linear module 800, the heating device, the lifting suction cup 400, the centering device 500, etc., and the control device 900 also has a display component 910, which can display the pressure value of the pressure sensor 181, etc. (see Fig.11 ).

[0034] The platform 300 is provided with a wafer carrier 310 , a lifting suction cup 400 , a centering device 500 , a lifting driving device 600 and a centering driving device 700 .

[0035] The wafer stage 310 is located on the top surface of the machine 300 and is provided with the heating device. The heating device can adopt existing technology and is used to heat and keep warm the wafer stage 310 and the wafer 1 thereon; the lifting suction cup 400 can be raised and lowered in the middle stage through hole 311 of the wafer stage 310; the centering device 500 is installed on the machine 300 and includes two symmetrically arranged clamping jaws 510. The two clamping jaws 510 can reciprocate along the radial direction of the wafer stage 310 to approach or move away from the wafer stage 310, and are used to relatively abut against the edge of the wafer 1; so as to align and position the wafer 1 placed on the wafer stage 310.

[0036] In addition, the machine platform 300 may be provided with a machine cover 320 and a machine base 330, the wafer carrier 310 is exposed on the top surface of the machine platform 300, and the two clamps 510 of the centering device 500 are movably arranged on both sides of the top surface of the machine platform 300. The machine cover 320 and the machine base 330 are used to protect the internal structure of the machine platform 300.

[0037] The centering device 500 also includes a notch alignment device 520; each clamping jaw 510 includes two clamping jaw abutment portions 511 arranged at intervals, wherein the notch alignment device 520 is arranged between the two clamping jaw abutment portions 511 of one clamping jaw 510, and the notch alignment device 520 includes a protrusion 521 for movably engaging and extending into the notch of the wafer 1 (not shown); the protrusion 521 and the clamping jaw abutment top portions 511 on both sides are arranged at intervals in the circumferential direction.

[0038] Therefore, when the two clamping jaws 510 move relatively close to each other to clamp and align the edges of the wafers 1, the protrusion 521 can move synchronously with the clamping jaws 510 and gradually fit into the notch openings of the two wafers 1. During the embedding process, the two wafers 1 are also aligned at the same time, that is, the two wafers 1 can be accurately aligned at one time, effectively ensuring the neatness of the two wafers 1 when loading.

[0039] Specifically, Figures 7 to 9 The lifting drive device 600 and the centering drive device 700 are installed below the wafer carrier 310 of the platform 300.

[0040] like Figure 7 and Fig. 9 The centering drive device 700 includes a centering cylinder 710, two clamping jaw fixing seats 720, two clamping jaw sliding seats 730 and two clamping jaw cylinders 740; the centering cylinder 710 is centered on the base bracket 331 of the machine base 330 below the center of the wafer carrier 310, and the two ends of the centering cylinder 710 respectively have power output ends 711 that move along the radial direction of the wafer carrier 310, and the power output ends 711 are respectively connected to one of the clamping jaw fixing seats 720, and the clamping jaw fixing seats 720 are simultaneously slidably connected to the base bracket 331 set on the machine base 330; thus, the power output ends 711 at both ends of the centering cylinder 710 can be extended or retracted at the same time, driving the two clamping jaw fixing seats 720 to move relatively away or close.

[0041] The clamping jaw sliding seat 730 is slidably connected to the clamping jaw fixing seat 720, the clamping jaw cylinder 740 is installed on the clamping jaw fixing seat 720, and the clamping jaw cylinder 740 drives the clamping jaw sliding seat 730 to slide back and forth on the clamping jaw fixing seat 720; the clamping jaw 510 is installed on the clamping jaw sliding seat 730; therefore, the centering cylinder 710 drives the clamping jaw fixing seat 720 to move relatively away from or close to each other, that is, it can drive the two clamping jaw sliding seats 730 and the clamping jaws 510 thereon to move relatively away from or close to each other, thereby achieving the clamping and alignment of the wafer 1; and the clamping jaw 510 can also be driven by the clamping jaw cylinder 740 to slide on the clamping jaw sliding seat 730, so that the distance between the two clamping jaws 510 can be adjusted to be suitable for wafers 1 of different sizes, thereby improving the adaptability of the device.

[0042] like Figure 7 and Figure 8The lifting drive device 600 includes a lifting cylinder 610 disposed on one side of the centering cylinder 710. The lifting cylinder 610 drives the suction cup bracket 620 to move up and down. One end of the suction cup bracket 620 is located below the wafer stage 310 and above the centering cylinder 710, and is installed with the lifting suction cup 400. The lifting suction cup 400 can be a vacuum suction cup, which can realize vacuum adsorption and fixation of the wafer 1. Therefore, the suction cup bracket 620 is driven to move up and down by the lifting cylinder 610, so as to drive the lifting suction cup 400 to move up and down in the middle stage through hole 311 of the wafer stage 310.

[0043] In this embodiment, a detection through hole 312 is further provided on the wafer carrier 310 , and a wafer detection sensor 313 is provided below the detection through hole 312 . The figure roughly shows a detection light 314 of the wafer detection sensor 313 , which is used to detect whether a wafer 1 is placed on the wafer carrier 310 .

[0044] Another example Fig.10 As shown, the present invention also provides a wafer bonding method, which mainly adopts the above-mentioned wafer bonding device to achieve effective bonding of the wafer 1 and improve the strength and precision of the bonding. The wafer bonding method includes the following steps: Step 1: Preliminary preparation: the airbag device 100, the lifting suction cup 400 and the centering device 500 are reset respectively, and the heating device heats and keeps the wafer stage 310 warm; Step 2: Wafer 1 is loaded; the lifting suction cup 400 is lifted from the middle of the wafer stage 310, and two wafers 1 to be bonded are stacked on the lifting suction cup 400 in sequence, and the notch openings of the two wafers 1 are kept preliminarily aligned, and at the same time face the protrusion 521 of the notch alignment device 520; the lifting suction cup 400 is controlled to absorb the wafer 1, and after the wafer 1 is driven to descend to the wafer stage 310, the absorption of the lifting suction cup 400 is disconnected, so that the wafer 1 is placed flat on the wafer stage 310; Step 3: Centering of wafer 1; the centering device 500 centers wafer 1, and the two clamping jaws 510 are relatively close to the wafer stage 310 along the radial direction of the wafer stage 310, and abut against the edge of the wafer 1 to align the edges of the two wafers 1, and at the same time, the protrusion 521 of the notch alignment device 520 gradually embeds into the notch of the two wafers 1 to be bonded as the clamping jaws 510 move, so that the two wafers 1 are further accurately aligned; Step 4: Wafer bonding; the airbag 140 of the airbag device 100 is inflated and pressurized, and at the same time, the vertical linear module 800 drives the airbag device 100 to descend. After the airbag 140 descends and abuts against the upper wafer 1, the floating mechanism 120 is used to enable the continuously inflated airbag 140 to adaptively level and cling to the upper wafer 1. At the same time, the vertical linear module 800 drives the airbag device 100 to descend. The bonding pressure is fed back in real time through the pressure sensor 181. When the bonding pressure reaches the first pressure value, the inflation is stopped, and the clamping claw 510 of the centering device 500 is controlled to reset and disengage from the wafer 1; then the vertical linear module 800 continues to drive the airbag device 100 to press down, further pressurize the two wafers 1, and when the bonding pressure reaches the second pressure value, the vertical linear module 800 is controlled to stop to maintain the pressure, and the duration of the first time period of the pressure maintenance; after the pressure maintenance is completed, the vertical linear module 800 drives the airbag device 100 to reset and exhaust the airbag 140; Step 5: unloading the bonding sheet; the lifting suction cup 400 rises to lift up the bonding sheet formed by the two wafers 1 bonded on the wafer carrier 310, and then take away the bonding sheet.

[0045] The first pressure value, the second pressure value and the value of the first time period can be selected and set according to actual production needs. For example, the first pressure value can be 1500g±100g, the second pressure value can be 2000g±100g, and the value of the first time period can be 2 seconds.

[0046] Thus, the two wafers 1 can be automatically aligned through the centering device 500, and adsorbed by the lifting suction cup 400 to ensure that the wafers 1 are not misaligned; an airbag device 100 is also provided, and the airbag 140 has an adaptive leveling function. The airbag device 100 is equipped with a pressure sensor 181, and the pressing force is controllable to ensure the tightness of the bonding.

[0047] During bonding, the present invention can remove bubbles in the two wafers 1 from the middle to the outside, ensuring that no bubbles are generated during wafer bonding. At the same time, the bonding force and stroke of the wafers are controllable, and the airbag device 100 has a pressure-maintaining function to achieve a wafer 1 flattening function, and can achieve stable bonding for warped wafers 1, which can effectively improve the flatness and bonding yield of the bonding sheet.

[0048] After adopting the above scheme, the present invention has the following advantages compared with the prior art: ① The overall structure of the present invention is compact, occupies a small area, and can be automated; ② The present invention can center and bond the wafer 1; ③ The present invention can realize controllable wafer bonding force and stroke; ④ The airbag 140 of the present invention is inflated into an arc shape, and bubbles in the two wafers 1 can be removed from the middle to the outside during bonding, ensuring that no bubbles are generated during wafer bonding; ⑤ The airbag 140 of the present invention has a pressure-maintaining function, realizes the wafer 1 leveling function, and can achieve stable bonding for the warped wafer 1.

[0049] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, equivalent changes and modifications without departing from the principle of the present invention should still belong to the protection scope of the present invention.

[0050] In the description of the embodiments of the present application, it should be understood that the indicated orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when in use, or is the orientation or position relationship commonly understood by technical personnel in this field. It 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.

Claims

1. A wafer bonding device, characterized in that: It comprises an airbag device for pressing wafers; the airbag device comprises a mounting frame, a floating mechanism, a fixed frame and an airbag which are arranged in sequence up and down; the airbag is installed below the fixed frame, and the fixed frame and the mounting frame are rotatably connected through the floating mechanism; the floating mechanism comprises a ball bearing and a plurality of support rods, the two ends of the ball bearing are respectively connected to the middle of the fixed frame and the middle of the mounting frame, the support rods are respectively distributed on the outer periphery of the ball bearing at circumferential intervals, the lower ends of the support rods are connected and fixed to the fixed frame, and the upper ends of the support rods are movably inserted into movable holes arranged on the mounting frame.

2. The wafer bonding device according to claim 1, characterized in that: A fixing groove is arranged in the middle of the fixing frame, a fixing rod is arranged horizontally in the fixing groove, the bearing part of the ball bearing is passed by the fixing rod and can rotate freely in the fixing groove, and the connecting rod part of the ball bearing is connected and fixed to the mounting frame.

3. The wafer bonding device according to claim 1, characterized in that: The movable hole is a countersunk hole arranged on the upper side of the mounting frame, and the countersunk hole passes through the bottom surface of the mounting frame; the support rods have four pieces, all of which are bolts, the heads of the bolts are accommodated in the movable holes, and the rods of the bolts pass downward through the movable holes and are locked and fixed with the fixing holes arranged on the fixing frame.

4. The wafer bonding device according to claim 1, characterized in that: An airbag mounting plate is provided below the fixing frame; the airbag mounting plate comprises an upper support plate and a lower support plate arranged up and down, and the upper part of the airbag is clamped and fixed by the upper support plate and the lower support plate; the lower support plate is annular, and the lower part of the airbag after inflation can expand downward from the annular hole of the lower support plate to form an arc bulge.

5. The wafer bonding device according to claim 4, characterized in that: A sensor mounting plate and a plurality of pressure sensors are provided between the airbag mounting plate and the fixing frame; the sensor mounting plate is connected to the top of the fixed airbag mounting plate, and the pressure sensors are distributed at intervals in the central circumferential direction of the fixing frame; the fixing frame and the sensor mounting plate are both disc-shaped, the outer diameter of the fixing frame is smaller than the outer diameter of the sensor mounting plate, the upper inner end of the pressure sensor is connected to the bottom of the fixing frame, and the lower outer end of the pressure sensor is connected to the top of the sensor mounting plate.

6. The wafer bonding device according to claim 5, characterized in that: The sensor mounting plate is provided with an upper groove which passes through from top to bottom between adjacent pressure sensors, and the upper part of the airbag is provided with a plurality of air nozzles which extend out of the upper support plate and are located in the upper groove.

7. The wafer bonding device according to claim 1, characterized in that: It also includes a machine frame, a machine table, a heating device, a lifting suction cup and a centering device; The frame and the machine platform are arranged adjacent to each other, a vertical linear module is installed on the frame, the airbag device is installed on the vertical linear module, the airbag device is suspended above the machine platform, and a pressure sensor is also arranged on the airbag device; The machine platform is provided with a wafer stage, and the wafer stage is provided with the heating device; the lifting suction cup can be lifted and lowered in the middle stage through hole of the wafer stage; the centering device is installed on the machine platform and includes two symmetrically arranged clamping claws, which can reciprocate along the radial direction of the wafer stage to approach or move away from the wafer stage, and are used to relatively abut against the edge of the wafer; The centering device also includes a notch alignment device; each clamp includes two clamp abutment portions arranged at intervals, and the notch alignment device is arranged between the two clamp abutment portions of one clamp, and the notch alignment device includes a protrusion for movably engaging and extending into the notch of the wafer; the protrusion and the clamp abutment tops on both sides are circumferentially spaced.

8. The wafer bonding device according to claim 7, characterized in that: A lifting drive device and a centering drive device are installed below the wafer carrier of the machine; The centering drive device comprises a centering cylinder, two clamping jaw fixing seats, two clamping jaw sliding seats and two clamping jaw cylinders; the centering cylinder is centrally located on the machine base below the center of the wafer stage, and both ends of the centering cylinder respectively have power output ends that move along the radial direction of the wafer stage, and the power output ends are respectively connected to one of the clamping jaw fixing seats, and the clamping jaw fixing seats are slidably connected to the machine base at the same time; the clamping jaw sliding seat is slidably connected to the clamping jaw fixing seat, the clamping jaw cylinder is installed on the clamping jaw fixing seat, and the clamping jaw cylinder drives the clamping jaw sliding seat to slide back and forth on the clamping jaw fixing seat; the clamping jaw is installed on the clamping jaw sliding seat; The lifting drive device includes a lifting cylinder arranged on one side of the centering cylinder, the lifting cylinder drives the suction cup bracket to move up and down, one end of the suction cup bracket is located below the wafer carrier and above the centering cylinder, and the lifting suction cup is installed, and the lifting suction cup is a vacuum suction cup.

9. The wafer bonding device according to claim 7, characterized in that: The wafer carrier is provided with a detection through hole, and a wafer detection sensor is provided below the detection through hole.

10. A wafer bonding method, using a wafer bonding device as claimed in any one of claims 7 to 9, characterized in that: The steps include: Step 1: Preliminary preparation: the airbag device, lifting suction cup and centering device are reset, and the heating device heats and keeps the wafer stage warm; Step 2: Wafer loading; the lifting suction cup is raised from the middle of the wafer stage, and two wafers to be bonded are stacked on the lifting suction cup in sequence, and the notch openings of the two wafers are kept initially aligned, and at the same time, they are aligned toward the protrusion of the notch opening alignment device; the lifting suction cup is controlled to absorb the wafer, and after the wafer is driven to descend to the wafer stage, the absorption of the lifting suction cup is disconnected, so that the wafer is placed flat on the wafer stage; Step 3: Wafer centering; The centering device centers the wafers, and the two clamping claws relatively approach the wafer stage along the radial direction of the wafer stage and abut against the edges of the wafers to align the edges of the two wafers. At the same time, the protrusion of the notch alignment device gradually embeds into the notch of the two wafers to be bonded as the clamping claws move, so that the two wafers can be further accurately aligned. Step 4: Wafer bonding; The airbag of the airbag device is inflated and pressurized, and at the same time, the vertical linear module drives the airbag device to descend. After the airbag descends and contacts the upper wafer, the floating mechanism is used to enable the continuously inflated airbag to adaptively level and cling to the upper wafer. At the same time, the bonding pressure is fed back in real time through the pressure sensor during the process of the vertical linear module driving the airbag device to descend. When the bonding pressure reaches a first pressure value, the inflation is stopped, and the clamping claws of the centering device are controlled to reset and detach from the wafer; then the vertical linear module continues to drive the airbag device downward to further pressurize the two wafers, and when the bonding pressure reaches a second pressure value, the vertical linear module is controlled to stop to maintain pressure, and the duration of the first pressure period is determined; after the pressure maintenance is completed, the vertical linear module drives the airbag device to reset, and then the airbag is exhausted; Step 5: Unloading the bonding sheet; the lifting suction cup rises, lifts up the bonding sheet formed by the two wafers bonded on the wafer carrier, and then takes away the bonding sheet.

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