Wafer bonding apparatus and wafer bonding method

Abstract

The embodiment of the present disclosure relates to the semiconductor field, and provides a wafer bonding device and a wafer bonding method, the wafer bonding device comprises: a contractible film layer, used for adsorbing a wafer to be bonded to an adsorption surface or releasing the wafer to be bonded adsorbed on the adsorption surface; the contractible film layer comprises a plurality of adjacent adsorption areas, different adsorption areas correspond to different areas of the adsorption surface; a pneumatic device is connected to the surface of the contractible film layer away from the adsorption surface, used for adjusting the air pressure in the adsorption area to control the deformation of the adsorption area. The embodiment of the present disclosure can at least improve the quality of wafer bonding.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the field of semiconductor, and particularly relates to a wafer bonding device and a wafer bonding method. BACKGROUND

[0002] A wafer bonding process can integrate two or more chips with the same or different functions in three dimensions. After wafer bonding, atoms at the interface react to form chemical bonds such as covalent bonds under the action of external force, so that the wafers are combined into one body, and the bonding interface reaches a specific bonding strength. Using the wafer bonding process can greatly reduce the chip development and manufacturing cycle, shorten the metal interconnection between functional chips, and reduce heat, power consumption and delay.

[0003] Wafer flatness is an important factor affecting bonding quality. However, the current wafer bonding device and wafer bonding method cannot effectively adjust the wafer deformation, resulting in poor wafer flatness and poor alignment accuracy of two wafers. SUMMARY

[0004] The wafer bonding device and wafer bonding method provided by the embodiments of the present disclosure at least have the advantages of adjusting the wafer deformation degree, ensuring the flatness of the wafer, and improving the bonding quality of the wafer.

[0005] According to some embodiments of the present disclosure, the wafer bonding device provided by the embodiments of the present disclosure comprises: a contractible film layer for adsorbing a wafer to be bonded to an adsorption surface or releasing the wafer to be bonded adsorbed on the adsorption surface; the contractible film layer comprises a plurality of adjacent adsorption zones, and different adsorption zones correspond to different areas of the adsorption surface; a pneumatic device connected to the surface of the contractible film layer away from the adsorption surface, for adjusting the air pressure in the adsorption zone to control the deformation of the adsorption zone.

[0006] According to some embodiments of the present disclosure, the wafer bonding method provided by another aspect of the embodiments of the present disclosure comprises: providing the wafer bonding device as described above; adjusting the pneumatic device to an adsorption mode, and adsorbing air to a plurality of adsorption zones to adsorb the wafer to be bonded to the adsorption surface; adjusting the pneumatic device to a release mode, and sequentially blowing air to a plurality of adsorption zones to gradually release the wafer to be bonded adsorbed on the adsorption surface by the contractible film layer.

[0007] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0008] The pneumatic device adjusts the air pressure in the plurality of suction areas of the retractable membrane layer to control the deformation of the suction areas. Since different suction areas correspond to different regions of the suction surface, the plurality of suction areas can adjust the deformation of different regions of the surface of the wafer to be bonded, thereby facilitating the guarantee of the flatness of the wafer to be bonded, so as to improve the quality of wafer bonding. BRIEF DESCRIPTION OF DRAWINGS

[0009] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the present disclosure. It is apparent that the accompanying drawings are only some embodiments of the present disclosure, and other drawings can be obtained according to the drawings without creative labor for those skilled in the art.

[0010] Figure 1 A schematic diagram of a wafer bonding device in the related art is shown;

[0011] Figure 2 A schematic diagram of a wafer bonding device provided by an embodiment of the present disclosure is shown;

[0012] Figure 3 A schematic diagram of a first membrane layer of a retractable membrane layer provided by an embodiment of the present disclosure is shown;

[0013] Figure 4 A schematic diagram of a second membrane layer of a retractable membrane layer provided by an embodiment of the present disclosure is shown;

[0014] Figure 5 A flowchart of a wafer bonding method provided by an embodiment of the present disclosure is shown;

[0015] Figure 6 A schematic diagram of a suction mode provided by an embodiment of the present disclosure is shown;

[0016] Figures 7-10 Different schematic diagrams of a release mode provided by an embodiment of the present disclosure in different stages are shown respectively. DETAILED DESCRIPTION

[0017] As known from the background, the current wafer bonding device and wafer bonding method are difficult to effectively adjust the deformation of the wafer, thereby resulting in poor flatness of the wafer and poor alignment accuracy of the two wafers. Referring to Figure 1, it is found through analysis that the main reason is that: the wafer bonding equipment currently comprises a first chuck 300 and a second chuck 400, the first chuck 300 is used for adsorbing a first wafer 100, and the second chuck 400 is used for carrying a second wafer 200. A pressing rod 500 is arranged on the first chuck 300. In the wafer bonding process, the pressing rod 500 presses the middle part of the first wafer 100, so that the middle part of the first wafer 100 first contacts the second wafer 200, and then the first wafer 100 is slowly bonded to the second wafer 200 along the crystal edge direction to form a chemical bond, that is, the pre-bonding is completed. However, the downward pressure of the pressing rod on the first wafer 100 will cause the first wafer 100 to generate a horizontal tensile stress, which will cause the first wafer 100 to deform like a bowl, thereby affecting the alignment accuracy along the crystal edge. That is, the deformation of the first wafer 100 causes the alignment deviation of the first wafer 100 and the second wafer 200 along the crystal edge to become larger.

[0018] The wafer bonding equipment provided by the embodiment of the present disclosure comprises a contractible film layer and a pneumatic device. Different adsorption zones of the contractible film layer correspond to different regions of the adsorption surface. By adjusting the air pressure of the adsorption zones through the pneumatic device, the deformation of the adsorption zones can be caused, and then the deformation of the wafer to be bonded can be adjusted. Compared with the pressing rod, the contractible film layer has a larger acting area with the wafer to be bonded, and can avoid the problem of stress concentration. In addition, the contractible film layer can independently adjust different regions of the wafer to be bonded, thereby facilitating the accurate control of the deformation of different regions.

[0019] The embodiments of the present disclosure will be described in detail below with reference to the drawings. However, those skilled in the art can understand that in the embodiments of the present disclosure, many technical details are proposed in order to enable the readers to better understand the embodiments of the present disclosure. However, the technical solutions claimed by the embodiments of the present disclosure can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0020] Figures 2-4 As shown, the embodiment of the present disclosure provides a wafer bonding equipment, which comprises: a contractible film layer 3, used for adsorbing a wafer to be bonded 1 to an adsorption surface 30 or releasing the wafer to be bonded 1 adsorbed on the adsorption surface 30; the contractible film layer 3 comprises a plurality of adjacent adsorption zones Z, different adsorption zones Z correspond to different regions of the adsorption surface 30; a pneumatic device 4 connected to the surface of the contractible film layer 3 away from the adsorption surface 30, used for adjusting the air pressure in the adsorption zone Z to control the deformation of the adsorption zone Z.

[0021] Such a design at least has the following advantages:

[0022] Firstly, compared with the pressure rod, the elastic of the retractable film layer 3 is better, and the pressure on the wafer to be bonded 1 is smaller. In addition, the acting area of the retractable film layer 3 and the wafer to be bonded 1 is larger, and the deformation of the wafer to be bonded 1 is smaller. In addition, the pressure rod can only exert force on the central region of the wafer to be bonded 1, and it is difficult to control the deformation of other regions, while the different suction zones Z of the retractable film layer 3 can be arranged opposite to different regions of the surface of the wafer to be bonded 1, so the deformation of multiple regions of the wafer to be bonded 1 can also be controlled individually, thereby facilitating the reduction of the tensile stress of the wafer to be bonded 1 in the horizontal direction.

[0023] Secondly, compared with the scheme of directly blowing air on the surface of the wafer to be bonded 1 to provide pressure, the retractable film layer 3 is beneficial to improve the stability of the air flow and avoid turbulence, thereby being capable of accurately controlling each region of the surface of the wafer to be bonded 1. In addition, the pressure of the air flow at the moment of ejection can be large, while the retractable film layer 3 can play a buffering role and indirectly act on the wafer to be bonded 1 through its own deformation, thereby reducing the pressure on the wafer to be bonded 1.

[0024] Thirdly, compared with the setting of multiple independent and spaced air bags, the retractable film layer 3 of the embodiment of the present disclosure is an integral whole, and the multiple suction zones Z are arranged adjacent to each other, when the deformation occurs in one of the suction zones Z, the adjacent suction zones Z will also be driven to produce slight deformation, that is, the elasticity of the retractable film layer 3 is good, and the suction surfaces 30 corresponding to different suction zones Z can drive each other, so that the junction of the two suction zones Z can form a smooth transition, so as to avoid the problem of stress concentration of the wafer to be bonded 1.

[0025] The wafer bonding device will be described in detail below.

[0026] Reference Figure 2 In some embodiments, the pneumatic device 4 includes a pneumatic branch pipe 41 and an electromagnetic valve 42 connected to the pneumatic branch pipe 41, the pneumatic branch pipe 41 is in communication with the suction zone Z, and the electromagnetic valve 42 is used to control the size and direction of the air flow into the suction zone Z.

[0027] For example, the pneumatic branch pipe 41 can be a Venturi tube. The Venturi tube is a pipe that is first contracted and then gradually expanded, for example, the Venturi tube is composed of an inlet section, a contraction section, a throat and a diffusion section arranged in sequence. Among them, the inlet section is a short cylindrical section. The contraction section is a conical pipe, which is contracted in the direction towards the throat. The throat is a short straight pipe section, and the diffusion section is a conical pipe, which is contracted in the direction towards the throat. The diffusion section of the Venturi tube gradually slows down the fluid, thereby reducing the turbulence and reducing the pressure head loss. In other embodiments, the pneumatic branch pipe 41 can also be a straight pipe.

[0028] Continuing to refer to Figure 2For example, the wafer to be bonded 1 can be a first wafer 10, and the wafer to be bonded with the first wafer 10 can be a second wafer 20. The wafer bonding device further comprises a carrier chuck 5 for carrying the second wafer 20. After the first wafer 10 and the second wafer 20 are pre-bonded, the carrier chuck 5 is further used for carrying the first wafer 10.

[0029] The shrinkable film layer 3 will be described in detail below.

[0030] With reference to Figures 2-4 The shrinkable film layer 3 can be made of a material with large elasticity, such as a silica gel adsorption film, so as to buffer the force acting on the wafer to be bonded 1 and reduce the deformation degree of the wafer to be bonded 1.

[0031] The shrinkable film layer 3 comprises a first film layer 31 and a second film layer 32 arranged oppositely. With reference to Figure 2 and Figure 3 The first film layer 31 is arranged towards the pneumatic device 4, and the first film layer 31 has a first air hole 311 through which the pneumatic device 4 supplies air or sucks air to the adsorption area Z. For example, the pneumatic branch pipe 41 is in communication with the first air hole 311, and the electromagnetic valve 42 is used to control the size and direction of the air flow into the first air hole 311. The first film layer 31 can be adhered to the pneumatic device 4 by means of an adhesive layer.

[0032] With reference to Figure 2 and Figure 4 The adsorption surface 30 is arranged on the second film layer 32, and the second film layer 32 has a second air hole 321; the second air hole 321 is used to provide a passage for the air flow on the surface of the wafer to be bonded 1 to be sucked into the adsorption area Z, or to provide a passage for the air flow in the adsorption area Z to be released outward.

[0033] With reference to Figures 2-4 The pneumatic device 4 has an adsorption mode and a release mode. In the adsorption mode, the plurality of electromagnetic valves 42 are opened, and the air flow on the surface of the wafer to be bonded 1 enters the adsorption area Z through the second air hole 321 and enters the pneumatic branch pipe 41 through the first air hole 311. Therefore, the shrinkable film layer 3 as a whole is in a contracted state, and the distance between the first film layer 31 and the second film layer 32 is reduced. In the release mode, the plurality of electromagnetic valves 42 are opened, and the air flow sequentially passes through the pneumatic branch pipe 41, the first air hole 311 and the adsorption area Z. The shrinkable film layer 3 as a whole is in an expanded state, and the distance between the first film layer 31 and the second film layer 32 is increased. With the increase of the air flow, the air flow flows out of the adsorption area Z through the second air hole 321 and acts on the upper surface of the wafer to be bonded 1, so that the wafer to be bonded 1 is separated from the shrinkable film layer 3. The two modes will be described in detail in the following wafer bonding method.

[0034] In some embodiments, with reference to Figures 2-3The size of the first gas hole 311 is greater than the size of the second gas hole 321. This is because: the deformation of the wafer to be bonded 1 is mainly adjusted by the deformation of the contractible film layer 3, so when the contact area of the wafer to be bonded 1 and the contractible film layer 3 is larger, the deformation of the wafer to be bonded 1 can be more accurately adjusted. The second gas hole 321 reduces the area of direct contact between the contractible film layer 3 and the wafer to be bonded 1, so the size of the second gas hole 321, i.e. the opening size, can be appropriately reduced to ensure the accuracy of adjusting the deformation of the wafer to be bonded 1. In addition, appropriately increasing the size of the first gas hole 311 can more flexibly control the size and speed of the gas flow. In other embodiments, the size of the first gas hole 311 can also be less than or equal to the size of the second gas hole 321.

[0035] In some embodiments, with reference to Figure 3 Each adsorption area Z corresponds to a first gas hole 311, which is beneficial to simplify the manufacturing process of the contractible film layer 3. In other embodiments, each adsorption area Z can also correspond to multiple first gas holes 311, and the multiple first gas holes 311 can be arranged at equal intervals, which can improve the uniformity of the gas flow and thus accurately control the deformation of the wafer to be bonded 1.

[0036] In some embodiments, with reference to Figure 4 Each adsorption area Z corresponds to multiple second gas holes 321, and the multiple second gas holes 321 can also be distributed at equal intervals, which can ensure the uniformity of the force received by the wafer to be bonded 1. For example, the total size of the multiple second gas holes 321 corresponding to each adsorption area Z is less than the total size of the first gas hole 311. In other embodiments, each adsorption area Z can also correspond to a second gas hole 321 to simplify the manufacturing process of the contractible film layer 3.

[0037] With reference to Figure 2 The contractible film layer 3 further comprises a third film layer 33, which is arranged around the circumferential edge of the first film layer 31 and the second film layer 32, and the three form a relatively closed space to limit the flow area of the gas flow.

[0038] It is worth noting that although the gas pressure size and direction of the multiple adsorption areas Z can be adjusted separately, the multiple adsorption areas Z can be in a state of incomplete isolation. For example, adjacent adsorption areas Z do not need to be provided with a film layer for shielding, and the two adsorption areas Z are completely connected. Thus, when the gas pressure of one adsorption area Z changes, part of the gas flow can enter the adjacent adsorption area Z, so that the gas pressure of the adjacent adsorption area Z also changes slightly, which can make the first film layer 31 corresponding to the adjacent adsorption area Z have a smooth transition, and thus ensure that the corresponding area of the wafer to be bonded 1 is also in a relatively smooth state, avoiding the generation of stress concentration points.

[0039] In some embodiments, the isolation film layer can be provided with micro-holes to allow micro air flow between adjacent adsorption zones Z. The micro air flow can reduce the air pressure difference between adjacent adsorption zones Z, and make the first film layer 31 more smooth and flexible. The isolation film layer can also allow more accurate adjustment of the air pressure of each adsorption zone Z.

[0040] In some embodiments, the isolation film layer can not be provided with micro-holes, so that adjacent adsorption zones Z are completely isolated. Since the elastic film layer 3 has good elasticity, when one adsorption zone Z is deformed, the adjacent adsorption zone Z can also be deformed, thereby achieving smooth transition of the adsorption surface 30.

[0041] In some embodiments, adjacent adsorption zones Z can be closely arranged, which can improve the driving effect between them to ensure smooth transition of the adsorption surface 30. In other embodiments, adjacent adsorption zones Z can also be slightly spaced apart and rely on the elasticity of the elastic film layer 3 to drive the adjacent adsorption zones Z.

[0042] In some embodiments, referring to Figures 2-3 , the plurality of adsorption zones Z are nested from inside to outside, wherein the innermost adsorption zone Z is arranged opposite to the center of the wafer 1 to be bonded, and the outermost adsorption zone Z is arranged opposite to the circumferential edge of the wafer 1 to be bonded. This can facilitate gradual control of the bonding process of the wafer 1 to be bonded in the direction from inside to outside, thereby avoiding the problem of warping of the wafer 1 to be bonded.

[0043] For example, the adsorption zones Z include first to fourth adsorption zones Z1 to Z4 nested from inside to outside. In the direction parallel to the adsorption surface 30, the cross-sectional shape of the first adsorption zone Z1 is circular, and the cross-sectional shapes of the second to fourth adsorption zones Z2 to Z4 are circular ring shapes. The wafer 1 to be bonded is circular in shape, so that the shapes of the adsorption zones Z are circular or circular ring shapes, which can make the shapes of the adsorption zones Z correspond to the shape of the wafer 1 to be bonded, thereby better controlling the deformation of each region of the surface of the wafer 1 to be bonded. It should be noted that the aforementioned direction parallel to the adsorption surface 30 refers to the direction when the adsorption surface 30 is not deformed.

[0044] In some embodiments, the ring width of the second adsorption zone Z2 is greater than the ring width of the third adsorption zone Z3, and greater than the radius of the first adsorption zone Z1. This is because: after the center of the first wafer 10 and the center of the second wafer 20 are bonded, the area near the center is bonded next, and the area near the center is prone to generate greater tensile stress, thereby causing the deformation of the bowl shape, so the alignment accuracy of the wafer edge area is easily affected by the deformation of the area; and the second adsorption zone Z2 corresponds to the area near the center of the first wafer 10 and the second wafer 20, that is, the second adsorption zone Z2 is the key position for adjusting the deformation of the first wafer 10; therefore, appropriately increasing the width of the second adsorption zone Z2 helps to flexibly control the air pressure of the area, thereby ensuring the effect of deforming and adjusting the first wafer 10.

[0045] For example, the radius of the first adsorption zone Z1 is 40 mm, the ring width of the second adsorption zone Z2 is 54 mm, the ring width of the third adsorption zone Z3 can be 39 mm, and the ring width of the fourth adsorption zone Z4 is 13 mm.

[0046] In some embodiments, the ring width of the fourth adsorption zone Z4 is less than the ring width of the second adsorption zone Z2 and the third adsorption zone Z3, and less than the radius of the first adsorption zone Z1. This is because: the wafer edge is the last area to be bonded in the wafer bonding process, and after the bonding of other areas is completed, the edge of the first wafer 10 (the wafer to be bonded 1) can slowly adhere to the second wafer 20 by means of the van der Waals force between the atoms on the wafer surface, so the width of the fourth adsorption zone Z4 can be appropriately reduced.

[0047] In some embodiments, the area of the shrinkable film layer 3 is equal to the area of the wafer to be bonded 1. In this way, the shrinkable film layer 3 can adjust the deformation process of the entire surface of the wafer to be bonded 1, thereby improving the bonding quality. In other embodiments, the area of the shrinkable film layer 3 can also be slightly larger or slightly smaller than the area of the wafer to be bonded 1. It should be noted that the area of the shrinkable film layer 3 can be understood as the area of the orthographic projection of the shrinkable film layer 3 on the supporting chuck 5, and the area of the wafer to be bonded 1 can be understood as the area of the orthographic projection of the wafer to be bonded 1 on the supporting chuck 5.

[0048] In some embodiments, the wafer bonding device further comprises: a gas pressure detection device for detecting the air pressure of the adsorption zone Z; and the electromagnetic valve 42 adjusts the air pressure of the adsorption zone Z based on the detection result of the gas pressure detection device. In this way, the accuracy of controlling the deformation of the shrinkable film layer 3 can be improved, thereby improving the wafer bonding quality. In some embodiments, the gas pressure detection device can monitor the air pressure of the adsorption zone Z in real time, and the electromagnetic valve 42 can adjust the air pressure in real time according to the detection result of the gas pressure detection device.

[0049] In summary, in the embodiments of the present disclosure, the wafer bonding device comprises a contractible film layer 3. Under the control of the pneumatic device 4, the contractible film layer 3 can be deformed, thereby adjusting the deformation degree of the wafer 1 to be bonded during the bonding process. The plurality of suction zones Z of the contractible film layer 3 can be controlled independently, so that the deformation of different regions of the wafer 1 to be bonded can also be adjusted independently. In addition, compared with the scheme of directly blowing or sucking the upper surface of the wafer 1 to be bonded without the contractible film layer 3, the contractible film layer 3 can make the stress of the wafer 1 to be bonded more gentle and stable, thereby improving the bonding precision. In addition, the plurality of suction zones Z of the contractible film layer 3 are arranged adjacent to each other, which can avoid the problem of steep deformation and stress concentration of the wafer 1 to be bonded due to the presence of the interval. In this way, it is beneficial to improve the alignment precision of the two wafers and ensure the quality of wafer bonding.

[0050] As shown in Figures 5-10 , another embodiment of the present disclosure provides a wafer bonding method, which can use the wafer bonding device provided by the foregoing embodiments. The wafer bonding method provided by an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0051] Referring to Figure 5 , step S1: providing a wafer bonding device, and the details of the wafer bonding device will be described with reference to the foregoing embodiments, which will not be described here.

[0052] Continuing to refer to Figure 5 , step S2: adjusting the pneumatic device 4 to the suction mode, and sucking the plurality of suction zones Z to make the first wafer 1 to be bonded (the first wafer 10) adsorbed on the adsorption surface 30.

[0053] For example, referring to Figure 6 , the plurality of suction zones Z are arranged in a nested manner from inside to outside. For example, in the direction parallel to the adsorption surface 30, the suction zones Z comprise first to fourth suction zones Z1 to Z4 arranged in a nested manner from inside to outside. The cross-sectional shape of the first suction zone Z1 is circular, and the cross-sectional shapes of the second to fourth suction zones Z2 to Z4 are annular.

[0054] Taking the foregoing adsorption zone Z as an example, the suction mode will be described below. Referring to Figure 6 , in some embodiments, the air pressure of the innermost suction zone Z is adjusted to be atmospheric pressure, and the air pressure of the remaining suction zones Z is adjusted to be negative pressure. That is, the air pressure of the first suction zone Z1 is atmospheric pressure, and the air pressure of the second to fourth suction zones Z2 to Z4 is negative pressure. Figure 6 The straight arrow in the figure shows the flow direction of the gas. In the negative pressure state, the pneumatic device 4 sucks the suction zone Z, for example, to a vacuum state. In the atmospheric pressure state, the pneumatic device 4 neither sucks nor blows the suction zone Z.

[0055] It should be noted that in the case where the second to fourth adsorption zones Z2 to Z4 are all set to negative pressure, the first wafer 10 is mostly adsorbed, and the first wafer 10 will not fall off or displace, so the first adsorption zone Z1 can be set to atmospheric pressure. In other embodiments, the air pressure of all adsorption zones Z can also be set to negative pressure. The range of negative pressure can be -6psi to -7psi, as long as the first wafer 10 can be adsorbed on the surface of the shrinkable film layer 3.

[0056] Thereafter, the first wafer 10 is aligned with the second wafer 20. Specifically, the first wafer 10 and the second wafer 20 each have alignment marks, and the relative positions of the two wafers are adjusted so that the alignment marks of the two wafers are aligned.

[0057] Reference Figure 5 , step S3: adjusting the pneumatic device 4 to a release mode, sequentially blowing air to the plurality of adsorption zones Z to gradually release the to-be-bonded wafer 1 (the first wafer 10) adsorbed on the adsorption surface 30 by the shrinkable film layer 3, thereby realizing pre-bonding of the first wafer 10 and the second wafer 20.

[0058] In some embodiments, the plurality of adsorption zones Z are nested from inside to outside. The release mode includes: sequentially blowing air to the plurality of adsorption zones Z in the direction from inside to outside. That is, the central region of the wafer is bonded first, and then other regions are sequentially bonded from inside to outside, which can effectively reduce the generation of air bubbles and improve the yield of products.

[0059] Taking the adsorption zones Z including the first to fourth adsorption zones Z1 to Z4 as an example, the release mode will be illustrated below. Referring to Figures 7-10 , the release mode includes: sequentially performing the first to fourth stages. Figures 7-10 The straight arrows in FIG. 4 schematically show the direction of the air flow. If the arrow is downward, it means that the pneumatic device 4 blows air toward the adsorption zone Z, and the adsorption zone Z is in a positive pressure state. If the arrow is upward, it means that the pneumatic device 4 sucks air from the adsorption zone Z, and the adsorption zone Z is in a negative pressure state. If no arrow is shown, it means that the pneumatic device 4 neither blows air nor sucks air, and the adsorption zone Z is in an atmospheric pressure state.

[0060] Reference Figure 7In the first stage, the gas pressure of the first adsorption area Z1 is adjusted to be positive, the gas pressure of the second adsorption area Z2 is adjusted to be atmospheric pressure, and the gas pressures of the third adsorption area Z3 and the fourth adsorption area Z4 are adjusted to be negative. In this way, the first adsorption area Z1 is in an expanded state, that is, the second membrane layer 32 corresponding to the first adsorption area Z1 protrudes away from the first membrane layer 31, thereby pushing the central region of the first wafer 10 to move towards the central region of the second wafer 20 to pre-bond the central regions of the two wafers. Since the second adsorption area Z2 is arranged adjacent to the first adsorption area Z1, the second adsorption area Z2 is slightly expanded under the action of the first adsorption area Z1, so that the region of the first wafer 10 opposite to the first adsorption area Z1 and the second adsorption area Z2 is in a smooth protruding state, so that the first wafer 10 can better recover to a flat state in the subsequent process.

[0061] It should be noted that, in the first stage, compared with setting the second adsorption area Z2 to negative pressure, adjusting the gas pressure of the second adsorption area Z2 to atmospheric pressure can reduce the pressure difference between the second adsorption area Z2 and the first adsorption area Z1, and ensure a smooth transition at the junction of the two. In addition, setting the second adsorption area Z2 to atmospheric pressure in advance can also prepare for the subsequent positive pressure state in the second stage, so as to avoid the gas pressure of the second adsorption area Z2 changing directly from negative pressure to positive pressure, thereby ensuring the stability of the gas flow.

[0062] Reference Figure 8 In the second stage, the gas pressures of the first adsorption area Z1 and the second adsorption area Z2 are adjusted to be positive, the gas pressure of the third adsorption area Z3 is adjusted to be atmospheric pressure, and the gas pressure of the fourth adsorption area Z4 is adjusted to be negative. In this way, the first adsorption area Z1 and the second adsorption area Z2 are both in an expanded state, and the third adsorption area Z3 is slightly expanded under the action of the second adsorption area Z2. The third adsorption area Z3 is at atmospheric pressure, thereby smoothly transitioning between the negative pressure state in the first stage and the positive pressure state in the subsequent third stage.

[0063] In the second stage, the entire region of the first wafer 10 opposite to the first adsorption area Z1 can be pre-bonded with the second wafer 20, and the other regions of the first wafer 10 can be spaced apart from the second wafer 20.

[0064] Reference Figure 9 In the third stage, the gas pressures of the first adsorption area Z1 to the third adsorption area Z3 are adjusted to be positive, and the gas pressure of the fourth adsorption area Z4 is adjusted to be negative. That is, the first adsorption area Z1 to the third adsorption area Z3 are all in an expanded state, and the fourth adsorption area Z4 is slightly expanded under the action of the third adsorption area Z3. In the third stage, the local region of the first wafer 10 opposite to the second adsorption area Z2 can be pre-bonded with the second wafer 20.

[0065] Reference Figure 10In the fourth stage, the air pressure of the first to fourth adsorption zones Z1 to Z4 is adjusted to be atmospheric pressure. In this way, the first wafer 10 is separated from the shrinkable film layer 3, and the edges of the two wafers are also pre-bonded. Subsequently, the first wafer 10 and the second wafer 20 can be subjected to a temperature rising process, thereby completing the entire bonding process.

[0066] In summary, in the embodiments of the present disclosure, by setting different adsorption zones Z to be in a state of positive pressure, negative pressure and atmospheric pressure, the deformation degree of the plurality of adsorption zones Z can be adjusted. In addition, by adjusting the air pressure of the adsorption zones Z at different time stages, the bonding process of the two wafers can be completed from the inside to the outside, thereby improving the alignment accuracy of the wafers.

[0067] In the description of the present specification, the description referring to the terms "some embodiments", "exemplarily", and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and modified by those skilled in the art without contradiction.

[0068] Although the embodiments of the present disclosure have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present disclosure, and any changes or modifications made in accordance with the claims and specification of the present disclosure shall be within the scope of the present disclosure.

Claims

1. A wafer bonding apparatus, characterized by comprising: The device comprises: a contractible membrane layer for adsorbing a wafer to be bonded to an adsorption surface or releasing the wafer to be bonded adsorbed on the adsorption surface; the contractible membrane layer comprises a plurality of adjacent adsorption areas corresponding to different areas of the adsorption surface; a pneumatic device connected to the surface of the contractible membrane layer away from the adsorption surface, for adjusting the air pressure in the adsorption area to control the deformation of the adsorption area; the contractible membrane layer comprises a first membrane layer and a second membrane layer arranged oppositely; the first membrane layer is arranged towards the pneumatic device, and the first membrane layer has a first air hole through which the pneumatic device supplies air or air suction to the adsorption area; the adsorption surface is arranged on the second membrane layer, and the second membrane layer has a second air hole; the second air hole is used to provide a channel for the air flow on the surface of the wafer to be bonded to enter the adsorption area, or to provide a channel for the air flow in the adsorption area to be released outward.

2. The wafer bonding device according to claim 1, wherein a plurality of the adsorption areas are arranged in a nested manner from inside to outside.

3. The wafer bonding device according to claim 2, wherein the adsorption areas comprise a first adsorption area, a second adsorption area, a third adsorption area and a fourth adsorption area nested in a nested manner from inside to outside in sequence, and in a direction parallel to the adsorption surface, a cross-sectional shape of the first adsorption area is circular, cross-sectional shapes of the second adsorption area to the fourth adsorption area are circular ring shapes, a ring width of the fourth adsorption area is smaller than ring widths of the second adsorption area and the third adsorption area, and smaller than a radius of the first adsorption area, and a ring width of the second adsorption area is greater than a ring width of the third adsorption area, and greater than the radius of the first adsorption area.

4. The wafer bonding device according to claim 1, wherein the pneumatic device comprises a pneumatic branch pipe and a solenoid valve connected to the pneumatic branch pipe, the pneumatic branch pipe is in communication with the first air hole, and the solenoid valve is used to control the size and direction of the air flow into the first air hole.

5. The wafer bonding apparatus of claim 4, wherein Further comprising: a gas pressure detection device for detecting the air pressure of the adsorption area; the solenoid valve adjusts the air pressure of the adsorption area based on the detection result of the gas pressure detection device.

6. A wafer bonding method characterized by, It comprises: providing the wafer bonding device according to any one of claims 1-5; adjusting the pneumatic device to an adsorption mode to air suction of a plurality of the adsorption areas, so as to adsorb the wafer to be bonded to the adsorption surface; adjusting the pneumatic device to a release mode to sequentially air blowing of a plurality of the adsorption areas, so as to gradually release the wafer to be bonded adsorbed on the adsorption surface by the contractible membrane layer.

7. The wafer bonding method according to claim 6, wherein a plurality of the adsorption areas are arranged in a nested manner from inside to outside; the release mode comprises: sequentially air blowing of a plurality of the adsorption areas in a direction from inside to outside.

8. The wafer bonding method according to claim 7, wherein the adsorption areas comprise a first adsorption area, a second adsorption area, a third adsorption area and a fourth adsorption area nested in a nested manner from inside to outside in sequence, and in a direction parallel to the adsorption surface, a cross-sectional shape of the first adsorption area is circular, and cross-sectional shapes of the second adsorption area to the fourth adsorption area are circular ring shapes. The release mode comprises: a first stage, a second stage, a third stage and a fourth stage in sequence; In the first stage, the air pressure of the first adsorption area is adjusted to positive pressure, the air pressure of the second adsorption area is adjusted to atmospheric pressure, and the air pressure of the third and fourth adsorption areas is adjusted to negative pressure; In the second stage, the air pressure of the first and second adsorption areas is adjusted to positive pressure, the air pressure of the third adsorption area is adjusted to atmospheric pressure, and the air pressure of the fourth adsorption area is adjusted to negative pressure; In the third stage, the air pressure of the first to third adsorption areas is adjusted to positive pressure, and the air pressure of the fourth adsorption area is adjusted to negative pressure; In the fourth stage, the air pressure of the first to fourth adsorption areas is adjusted to atmospheric pressure.

9. The wafer bonding method according to claim 6, wherein, The plurality of adsorption areas are arranged in a nested manner from inside to outside; The adsorption mode comprises: adjusting the air pressure of the innermost adsorption area to atmospheric pressure, and adjusting the air pressure of the remaining adsorption areas to negative pressure.

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