CN116110843A

CN116110843A - Wafer bonding apparatus and wafer bonding method

Info

Publication number: CN116110843A
Application number: CN202310234538.8A
Authority: CN
Inventors: 金松杰
Original assignee: Changxin Memory Technologies Inc
Current assignee: Changxin Memory Technologies Inc
Priority date: 2023-03-07
Filing date: 2023-03-07
Publication date: 2023-05-12

Abstract

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

Description

Wafer bonding apparatus and wafer bonding method

Technical Field

The disclosure belongs to the field of semiconductors, and in particular relates to wafer bonding equipment and a wafer bonding method.

Background

A wafer bonding process may three-dimensionally integrate two or more chips having the same or different functions. After the wafers are bonded, atoms of the interface react under the action of external force to form chemical bonds such as covalent bonds, so that the wafers are integrated, and the bonding interface reaches a specific bonding strength. The wafer bonding process can greatly reduce the chip research and development and manufacturing period, shorten the metal interconnection between the functional chips, and reduce the heat generation, the power consumption and the delay.

Wafer flatness is an important factor affecting bonding quality, however, current wafer bonding equipment and wafer bonding methods are difficult to effectively adjust wafer deformation, so that wafer flatness is poor, and alignment accuracy of two wafers is poor.

Disclosure of Invention

The embodiment of the disclosure provides wafer bonding equipment and a wafer bonding method, which are at least beneficial to adjusting the deformation degree of a wafer, ensuring the flatness of the wafer and further improving the bonding quality of the wafer.

According to some embodiments of the present disclosure, an aspect of the embodiments of the present disclosure provides a wafer bonding apparatus, wherein the wafer bonding apparatus includes: the shrinkable film layer is used for adsorbing the wafer to be bonded to an adsorption surface or releasing the wafer to be bonded adsorbed on the adsorption surface; the shrinkable film layer comprises a plurality of adjacent adsorption areas, and different adsorption areas correspond to different areas of the adsorption surface; and the pneumatic device is connected with the surface of the shrinkable film layer, which is far away from the adsorption surface, and is used for adjusting the air pressure in the adsorption area so as to control the deformation of the adsorption area.

According to some embodiments of the present disclosure, another aspect of embodiments of the present disclosure further provides a wafer bonding method, providing a wafer bonding apparatus as described above; adjusting the pneumatic device to an adsorption mode, and sucking air into a plurality of adsorption areas so as to enable the wafer to be bonded to be adsorbed to the adsorption surface; and adjusting the pneumatic device to a release mode, and sequentially blowing air to a plurality of adsorption areas so that the shrinkable film layer gradually releases the wafers to be bonded adsorbed on the adsorption surface.

The technical scheme provided by the embodiment of the disclosure has at least the following advantages:

the pneumatic device adjusts the air pressure in a plurality of adsorption areas of the shrinkable film layer so as to control the deformation of the adsorption areas. Because different adsorption areas correspond to different areas of the adsorption surface, the adsorption areas can carry out deformation adjustment on different areas of the surface of the wafer to be bonded, so that the smoothness of the wafer to be bonded is guaranteed, and the bonding quality of the wafer is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure. It will be apparent to those of ordinary skill in the art that the drawings in the following description are merely examples of the disclosure and that other drawings may be derived from them without undue effort.

FIG. 1 shows a schematic diagram of a wafer bonding apparatus in the related art;

fig. 2 shows a schematic diagram of a wafer bonding apparatus according to an embodiment of the present disclosure;

FIG. 3 illustrates a schematic view of a first film layer of a shrinkable film layer provided in an embodiment of the present disclosure;

FIG. 4 illustrates a schematic view of a second film layer of a shrinkable film layer provided by embodiments of the present disclosure;

fig. 5 shows a flowchart of a wafer bonding method provided by an embodiment of the present disclosure;

FIG. 6 shows a schematic diagram of an adsorption mode provided by an embodiment of the present disclosure;

fig. 7-10 respectively show different schematic diagrams of the release pattern provided by embodiments of the present disclosure at different stages.

Detailed Description

As known from the background art, the current wafer bonding apparatus and the wafer bonding method are difficult to effectively adjust the wafer deformation, so that the wafer flatness is poor, and the alignment accuracy of two wafers is poor. Referring to fig. 1, it was found by analysis that the main reason is: the current wafer bonding apparatus includes a first chuck 300 and a second chuck 400, the first chuck 300 being used for sucking the first wafer 100, and the second chuck 400 being used for carrying the second wafer 200. The first chuck 300 is provided with a pressing rod 500. 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 contacts the second wafer 200 first, and then the first wafer 100 is bonded with the second wafer 200 along with the wafer edge direction slowly by the van der waals force between atoms on the surface of the first wafer 100 to form a chemical bond, so as to complete pre-bonding. However, the downward pressure of the pressing rod on the first wafer 100 may cause the first wafer 100 to generate a tensile stress in a horizontal direction, which may cause the first wafer 100 to deform like a bowl, thereby affecting the alignment accuracy along the edge of the wafer. That is, the deformation of the first wafer 100 causes the alignment deviation of the first and

second wafers

100 and 200 along the crystal edge to become large.

The embodiment of the disclosure provides wafer bonding equipment. The wafer bonding apparatus includes a shrinkable film layer and a pneumatic device. Wherein, the different adsorption areas of collapsible rete correspond the different regions of adsorption surface, adjust the atmospheric pressure of adsorption area through pneumatic means, can make the adsorption area take place deformation, and then adjust the deformation of waiting to bond the wafer. Compared with the compression bar, the action area of the shrinkable film layer and the wafer to be bonded is larger, and the problem of stress concentration can be avoided. In addition, the shrinkable film layer can be independently adjusted in different areas of the wafer to be bonded, so that deformation of the different areas can be accurately controlled.

Embodiments of the present disclosure will be described in detail below with reference to the attached drawings. However, those of ordinary skill in the art will understand that in the various embodiments of the present disclosure, numerous technical details have been set forth in order to provide a better understanding of the embodiments of the present disclosure. However, the technical solutions claimed in the embodiments of the present disclosure can be implemented without these technical details and based on various changes and modifications of the following embodiments.

2-4, an embodiment of the present disclosure provides a wafer bonding apparatus, including: a shrinkable film layer 3 for adsorbing the wafer 1 to be bonded to the adsorption surface 30 or releasing the wafer 1 to be bonded adsorbed on the adsorption surface 30; the shrinkable film layer 3 comprises a plurality of adjacent adsorption zones Z, and different adsorption zones Z correspond to different areas of the adsorption surface 30; and the pneumatic device 4 is connected with the surface of the shrinkable film layer 3 away from the adsorption surface 30 and is used for adjusting the air pressure in the adsorption zone Z so as to control the deformation of the adsorption zone Z.

Such a design has at least the following advantages:

first, the elasticity of the shrinkable film layer 3 is better and the pressure to be applied to the wafer 1 to be bonded is smaller than that of the compression bar. In addition, the action area of the shrinkable film layer 3 and the wafer 1 to be bonded is larger, and the deformation of the wafer 1 to be bonded is smaller. In addition, the compression bar can only apply an acting force to the central area of the wafer 1 to be bonded, so that the deformation of other areas is difficult to control, and different adsorption areas Z of the shrinkable film layer 3 can be arranged opposite to different areas on the surface of the wafer 1 to be bonded, so that the deformation of a plurality of areas of the wafer 1 to be bonded can be independently controlled, thereby being beneficial to reducing the tensile stress of the wafer 1 to be bonded in the horizontal direction.

Secondly, compared with the scheme of directly blowing air to the surface of the wafer 1 to be bonded to provide pressure, the shrinkable film layer 3 is beneficial to improving the stability of air flow and avoiding turbulent flow, so that each area of the surface of the wafer 1 to be bonded can be accurately controlled. In addition, the pressure at the moment of air flow ejection may be larger, and the shrinkable film layer 3 may play a role of buffering and indirectly act on the wafer 1 to be bonded through self deformation, so as to reduce the pressure to which the wafer 1 to be bonded is subjected.

Third, compare in setting up a plurality of independence and spaced gasbag, but shrinkable film layer 3 of this disclosed embodiment is a whole, and a plurality of absorption district Z are adjacent to be set up, when one of them absorption district Z takes place deformation, adjacent absorption district Z also can be driven and produce slight deformation, can shrink film layer 3's elasticity good, and absorption face 30 that different absorption district Z correspond can drive each other for two absorption district Z's juncture can form smooth transition like this, in order to avoid appearing waiting to bond wafer 1 to appear stress concentration's problem.

The wafer bonding apparatus will be described in detail below.

Referring to fig. 2, in some embodiments, the pneumatic device 4 includes a pneumatic manifold 41 and a solenoid valve 42 connected to the pneumatic manifold 41, the pneumatic manifold 41 being in communication with the adsorption zone Z, the solenoid valve 42 being used to control the magnitude and direction of the air flow into the adsorption zone Z.

The pneumatic manifold 41 may be a venturi, for example. The venturi is a conduit that is first constricted and then gradually enlarged, for example, the venturi is composed of an inlet section, a constriction section, a throat section, and a diffuser section, which are arranged in this order. Wherein the inlet section is a short cylindrical section. The contraction section is a conical tube and contracts in the direction toward the throat section. The throat is a short straight pipe section, and the diffusion section is a conical pipe and is contracted in the direction towards the throat section. The diverging section of the venturi gradually slows down the fluid, thereby reducing turbulence and reducing head loss. In other embodiments, the pneumatic manifold 41 may be a straight tube.

With continued reference to fig. 2, for example, the wafer 1 to be bonded may be a first wafer 10 and the wafer bonded thereto may be a second wafer 20. The wafer bonding apparatus further comprises a carrier chuck 5, the carrier chuck 5 being adapted to carry a second wafer 20. The carrier chuck 5 is also used to carry the first wafer 10 after the first wafer 10 and the second wafer 20 are pre-bonded.

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

Referring to fig. 2-4, the shrinkable film layer 3 may be made of a material with relatively high elasticity, such as a silica gel adsorption film, so as to buffer the acting force applied to the wafer 1 to be bonded, so as to reduce the deformation degree thereof.

The shrinkable film layer 3 comprises a first film layer 31 and a second film layer 32 arranged opposite each other. Referring to fig. 2 and 3, the first membrane layer 31 is disposed toward the air moving device 4, the first membrane layer 31 having first air holes 311, and the air moving device 4 inflating or deflating the adsorption zone Z through the first air holes 311. Illustratively, the pneumatic manifold 41 communicates with the first air aperture 311 and the solenoid valve 42 is used to control the magnitude and direction of the air flow into the first air aperture 311. The first film 31 may be adhered to the pneumatic device 4 by an adhesive layer.

Referring to fig. 2 and 4, the adsorption surface 30 is disposed on the second membrane layer 32, and the second membrane layer 32 has second air holes 321; the second air holes 321 are used to provide a passage through which an air flow to be bonded to the surface of the wafer 1 is sucked into the adsorption zone Z, or a passage through which an air flow in the adsorption zone Z is discharged outward.

Referring to fig. 2-4 in combination, the pneumatic device 4 has an adsorption mode and a release mode. In the adsorption mode, the plurality of solenoid valves 42 are opened, and the air flow to be bonded to the surface of the wafer 1 enters the adsorption zone Z through the second air holes 321 and enters the pneumatic manifold 41 through the first air holes 311. Therefore, the shrinkable film layer 3 is entirely in a shrunk state, and the distance between the first film layer 31 and the second film layer 32 becomes smaller. In the release mode, the plurality of solenoid valves 42 are opened and the air flow passes through the air branch 41, the first air holes 311 and the adsorption zone Z in sequence. The shrinkable film layer 3 is in an expanded state as a whole, and the distance between the first film layer 31 and the second film layer 32 increases. As the air flow increases, the air flow flows out of the adsorption zone Z through the second air holes 321 and acts on the upper surface of the wafer 1 to be bonded, so that the wafer 1 to be bonded is separated from the shrinkable film layer 3. These two modes will be described in detail later in connection with the wafer bonding method.

In some embodiments, referring to fig. 2-3 in contrast, the first air holes 311 have a larger size than the second air holes 321. This is because: the deformation of the wafer 1 to be bonded is mainly adjusted through the deformation of the shrinkable film layer 3, so that the deformation of the wafer 1 to be bonded can be adjusted more accurately when the contact area between the wafer 1 to be bonded and the shrinkable film layer 3 is large. The second air hole 321 reduces the area of the shrinkable film layer 3 in direct contact with the wafer 1 to be bonded, so that the size of the second air hole 321, i.e. the opening size of the second air hole 321, can be properly reduced to ensure the accuracy of adjusting the deformation of the wafer 1 to be bonded. In addition, the size of the first air holes 311 is appropriately increased to allow more flexible control of the air flow size and speed. In other embodiments, the size of the first air holes 311 may be smaller than or equal to the size of the second air holes 321.

In some embodiments, referring to fig. 3, each adsorption zone Z is provided with a first air hole 311, which is beneficial to simplify the manufacturing process of the shrinkable film layer 3. In other embodiments, each adsorption zone Z may be provided with a plurality of first air holes 311 correspondingly, and the plurality of first air holes 311 may be arranged at equal intervals, so that uniformity of air flow can be improved, and deformation of the wafer 1 to be bonded is precisely controlled.

In some embodiments, referring to fig. 4, each adsorption zone Z is correspondingly provided with a plurality of second air holes 321, and the plurality of second air holes 321 may also be distributed at equal intervals, so that the uniformity of the stress of the wafer 1 to be bonded can be ensured. For example, the total size of the second air holes 321 corresponding to each adsorption zone Z is smaller than the total size of the first air holes 311. In other embodiments, each adsorption zone Z may be provided with a second air hole 321, so as to simplify the manufacturing process of the shrinkable film layer 3.

Referring to fig. 2, the shrinkable film layer 3 further includes a third film layer 33, wherein the third film layer 33 is disposed around the circumferential edges of the first film layer 31 and the second film layer 32, and the three layers enclose a relatively closed space to restrict the flow area of the air flow.

It should be noted that, although the air pressures and directions of the plurality of adsorption zones Z may be individually adjusted, the plurality of adsorption zones Z may be incompletely isolated from each other. For example, a film layer for shielding is not required to be arranged between the adjacent adsorption zones Z, and the two adsorption zones Z are completely communicated. Therefore, when the air pressure of one adsorption zone Z changes, part of the air flow can enter the adjacent adsorption zone Z, so that the air pressure of the adjacent adsorption zone Z slightly changes, the first film 31 corresponding to the adjacent adsorption zone Z has smooth transition, and the area corresponding to the wafer 1 to be bonded is ensured to be in a relatively smooth state, so that stress concentration points are avoided.

In other embodiments, a separation membrane layer may be disposed between adjacent adsorption zones Z, where micropores are disposed to allow the transfer of minute gas flows between adjacent zones. The minute air flow can reduce the air pressure difference at the boundary of the adjacent regions so that the first film 31 is smoother and more stretched. The isolation film layer can also enable the air pressure of each adsorption zone Z to be more accurately adjusted.

In other embodiments, the isolation film layer may not be provided with micropores, so that the adjacent adsorption zones Z are completely isolated. Because the elasticity of the shrinkable film layer 3 is good, when one adsorption zone Z deforms, the adjacent adsorption zone Z can be driven to deform, so that smooth transition of the adsorption surface 30 is realized.

In some embodiments, adjacent suction zones Z may be disposed in close proximity, which may enhance the entrainment therebetween to ensure a smooth transition of suction face 30. In other embodiments, the adjacent adsorption zones Z may be slightly spaced apart, and the adjacent adsorption zones Z may be driven by the elasticity of the shrinkable film layer 3.

In some embodiments, referring to fig. 2-3, the plurality of suction zones Z are nested inside-out, wherein an innermost suction zone Z is disposed opposite a center of the wafer 1 to be bonded and an outermost suction zone Z is disposed opposite a circumferential edge of the wafer 1 to be bonded. Thus, the bonding process of the wafer 1 to be bonded can be controlled gradually along the direction from inside to outside, and the problem of warping of the wafer 1 to be bonded is avoided.

For example, the adsorption zone Z includes first to fourth adsorption zones Z1 to Z4 nested in order from inside to outside, the cross-sectional shape of the first adsorption zone Z1 is circular in the direction parallel to the adsorption surface 30, and the cross-sectional shape of the second to fourth adsorption zones Z2 to Z4 is circular. The shape of the wafer 1 to be bonded is circular, so that the shape of the adsorption zone Z is set to be circular or annular, the shape of the adsorption zone Z corresponds to the shape of the wafer 1 to be bonded, and the deformation of each area on the surface of the wafer 1 to be bonded is better controlled. It should be noted that the direction parallel to the suction surface 30 refers to a direction in which the suction surface 30 is not deformed.

In some embodiments, the second adsorption zone Z2 has a ring width that 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 centers of the first wafer 10 and the second wafer 20 are bonded, the areas of the sub-centers are bonded immediately, and the areas of the sub-centers are easy to generate larger tensile stress, so that bowl-shaped deformation is easy to be caused, and the alignment precision of the wafer edge areas is easy to be influenced by the deformation of the areas; the second adsorption zone Z2 corresponds to the region of the sub-center of the first wafer 10 and the second wafer 20, that is, the second adsorption zone Z2 is a key position for adjusting the deformation of the first wafer 10; therefore, properly increasing the width of the second adsorption zone Z2 helps to flexibly control the air pressure of the zone, thereby ensuring the effect of deformation adjustment of the first wafer 10.

Illustratively, the radius of the first adsorption zone Z1 is 40mm, the annular width of the second adsorption zone Z2 is 54mm, the annular width of the third adsorption zone Z3 may be 39mm, and the annular width of the fourth adsorption zone Z4 is 13mm.

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

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

In some embodiments, the wafer bonding apparatus further comprises: the air pressure detection device is used for detecting the air pressure of the adsorption zone Z; the solenoid valve 42 adjusts the air pressure in the adsorption zone Z based on the detection result of the air pressure detection device. Therefore, the accuracy of controlling the deformation of the shrinkable film layer 3 can be improved, and the bonding quality of the wafer can be further improved. In some embodiments, the air pressure detecting device may monitor the air pressure of the adsorption zone Z in real time, and the electromagnetic valve 42 may adjust the air pressure in real time according to the detection result of the air pressure detecting device.

In summary, in the embodiments of the present disclosure, the wafer bonding apparatus includes the shrinkable film layer 3. Under the control of the pneumatic device 4, the shrinkable film layer 3 can deform, so as to adjust the deformation degree of the wafer 1 to be bonded in the bonding process. The plurality of adsorption zones Z of the shrinkable film layer 3 can control the air pressure independently, so that the deformations of different areas of the wafer 1 to be bonded can be adjusted independently. In addition, compared with the scheme of omitting the shrinkable film layer 3 and directly blowing or sucking air on the upper surface of the wafer 1 to be bonded, the arrangement of the shrinkable film layer 3 can enable the stress of the wafer 1 to be bonded to be more gentle and stable, so that the bonding precision is improved. In addition, the plurality of adsorption zones Z of the shrinkable film layer 3 are adjacently arranged, so that the problems of steep deformation and stress concentration of the wafer 1 to be bonded caused by the occurrence of interval zones can be avoided. Thus, the alignment precision of two wafers is improved, and the bonding quality of the wafers is ensured.

As shown in fig. 5 to 10, another embodiment of the present disclosure provides a wafer bonding method, which may utilize the wafer bonding apparatus provided in the foregoing embodiment, and the wafer bonding method provided in one embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

Referring to fig. 5, step S1: for a detailed description of the wafer bonding apparatus, please refer to the foregoing embodiments, and the detailed description is omitted herein.

With continued reference to fig. 5, step S2: the pneumatic device 4 is adjusted to the adsorption mode, and the plurality of adsorption zones Z are suctioned so that the first wafer 1 (first wafer 10) to be bonded is adsorbed on the adsorption surface 30.

Illustratively, referring to fig. 6, the plurality of adsorption zones Z are nested from inside to outside, for example, in a direction parallel to the adsorption surface 30, the adsorption zone Z includes first to fourth adsorption zones Z1 to Z4 nested from inside to outside in sequence, the first adsorption zone Z1 has a circular cross-sectional shape, and the second to fourth adsorption zones Z2 to Z4 have a circular cross-sectional shape.

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

In the case where the second to fourth suction areas Z2 to Z4 are set to the negative pressure, most of the area of the first wafer 10 is already sucked, and the first wafer 10 does not fall off or shift, so the first suction area Z1 can be set to the atmospheric pressure. In other embodiments, the air pressure in all the adsorption zones Z may be set to negative pressure. The negative pressure may range from-6 psi to-7 psi, as long as the first wafer 10 is securely adsorbed onto the surface of the shrinkable film layer 3.

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

Referring to fig. 5, step S3: the pneumatic device 4 is adjusted to a release mode, and the plurality of adsorption areas Z are sequentially blown, so that the shrinkable film layer 3 gradually releases the wafer 1 to be bonded (the first wafer 10) adsorbed on the adsorption surface 30, and the first wafer 10 and the second wafer 20 are pre-bonded.

In some embodiments, the plurality of suction zones Z are nested inside-out. The release mode includes: the plurality of adsorption zones Z are sequentially blown in the inside-out direction. That is, the central area of the wafer is bonded first, and then other areas are bonded sequentially from inside to outside, so that the generation of bubbles can be effectively reduced, and the yield of products is improved.

Taking the case where the adsorption zone Z includes the aforementioned first adsorption zone Z1 to fourth adsorption zone Z4 as an example, the release mode will be exemplified below. Referring to fig. 7-10, the release mode includes: the first stage to the fourth stage are sequentially performed. The straight arrows in fig. 7-10 illustrate the direction of the air flow, and if the arrows are downward, the pneumatic device 4 blows air towards the adsorption zone Z, and the adsorption zone Z is in a positive pressure state; if the arrow is upward, the pneumatic device 4 sucks air in the adsorption zone Z, and the adsorption zone Z is in a negative pressure state; if the arrows are not shown, the surface pneumatic device 4 neither blows nor sucks air, and the adsorption zone Z is in an atmospheric pressure state.

Referring to fig. 7, in the first stage, the air pressure of the first adsorption zone Z1 is adjusted to a positive pressure, the air pressure of the second adsorption zone Z2 is adjusted to an atmospheric pressure, and the air pressures of the third adsorption zone Z3 and the fourth adsorption zone Z4 are adjusted to a negative pressure. In this way, the first adsorption zone Z1 is in an expanded state, that is, the second film 32 corresponding to the first adsorption zone Z1 protrudes away from the first film 31, so as to push the central area of the first wafer 10 to move toward the central area of the second wafer 20, so that the central areas of the two wafers are pre-bonded. Because the second adsorption zone Z2 is disposed adjacent to the first adsorption zone Z1, the second adsorption zone Z2 is subjected to the force of the first adsorption zone Z1 and is in a slightly expanded state, so that the area of the first wafer 10 opposite to the first adsorption zone Z1 and the second adsorption zone Z2 presents a smooth convex state, so that the subsequent first wafer 10 can better recover the flat state.

It should be noted that, in the first stage, compared with setting the second adsorption zone Z2 to be negative pressure, the air pressure of the second adsorption zone Z2 is adjusted to be atmospheric pressure, so that the air pressure difference between the second adsorption zone Z2 and the first adsorption zone Z1 can be reduced, and a gentle transition is ensured at the junction of the two. In addition, the second adsorption zone Z2 is set to be the atmospheric pressure in advance, and preparation can be made for the positive pressure state of the subsequent second stage, so that the condition that the air pressure of the second adsorption zone Z2 is directly changed from negative pressure to positive pressure is avoided, and the stability of air flow is ensured.

Referring to fig. 8, in the second stage, the air pressures of the first adsorption zone Z1 and the second adsorption zone Z2 are adjusted to positive pressure, the air pressure of the third adsorption zone Z3 is adjusted to atmospheric pressure, and the air pressure of the fourth adsorption zone Z4 is adjusted to negative pressure. Thus, the first adsorption zone Z1 and the second adsorption zone Z2 are both in an expanded state, and the third adsorption zone Z3 is subjected to the force of the second adsorption zone Z2 and is also in a slightly expanded state. The third adsorption zone Z3 is at atmospheric pressure so as to be able to smoothly transition between the negative pressure state of the first stage and the positive pressure state of the subsequent third stage.

In the second stage, the entire area of the first wafer 10 opposite to the first suction zone Z1 may be pre-bonded with the second wafer 20, and other areas of the first wafer 10 may be spaced apart from the second wafer 20.

Referring to fig. 9, in the third stage, the air pressures of the first to third adsorption zones Z1 to Z3 are adjusted to positive pressure and the air pressure of the fourth adsorption zone Z4 is adjusted to negative pressure. That is, the first to third adsorption zones Z1 to Z3 are all in an expanded state, and the fourth adsorption zone Z4 is subjected to the force of the third adsorption zone Z3 and is also in a slightly expanded state. In the third stage, the partial region of the first wafer 10 opposite to the second suction zone Z2 may be pre-bonded with the second wafer 20.

Referring to fig. 10, in the fourth stage, the air pressures of the first to fourth adsorption zones Z1 to Z4 are adjusted to the atmospheric pressure. Thus, the first wafer 10 is separated from the shrinkable film layer 3, and the edges of the two wafers are also pre-bonded. The first wafer 10 and the second wafer 20 may be subsequently subjected to a temperature raising process, thereby completing the entire bonding process.

In summary, in the embodiment of the present disclosure, the deformation degrees of the plurality of adsorption zones Z may be adjusted by setting the different adsorption zones Z to the positive pressure, negative pressure, and atmospheric pressure states. In addition, the air pressure of the adsorption zone Z is adjusted in a plurality of time steps, so that the bonding process of two wafers can be finished sequentially from inside to outside, and the alignment accuracy of the wafers is improved.

In the description of the present specification, a description of the terms "some embodiments," "exemplary," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present disclosure have been shown and described above, it should be understood that the above embodiments are illustrative and not to be construed as limiting the present disclosure, and that variations, modifications, alternatives, and variations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present disclosure, which is therefore intended to be within the scope of the present disclosure as defined by the claims and specification.

Claims

1. A wafer bonding apparatus, comprising:

the shrinkable film layer is used for adsorbing the wafer to be bonded to an adsorption surface or releasing the wafer to be bonded adsorbed on the adsorption surface; the shrinkable film layer comprises a plurality of adjacent adsorption areas, and different adsorption areas correspond to different areas of the adsorption surface;

and the pneumatic device is connected with the surface of the shrinkable film layer, which is far away from the adsorption surface, and is used for adjusting the air pressure in the adsorption area so as to control the deformation of the adsorption area.

2. The wafer bonding apparatus of claim 1 wherein,

the shrinkable film layer comprises a first film layer and a second film layer which are oppositely arranged;

the first film layer is arranged towards the pneumatic device, the first film layer is provided with a first air hole, and the pneumatic device charges or sucks air into the adsorption area through the first air hole;

the adsorption surface is arranged on the second film layer, and the second film layer is provided with second air holes; the second air hole is used for providing a channel for sucking the air flow on the surface of the wafer to be bonded into the adsorption area or providing a channel for outwards releasing the air flow in the adsorption area.

3. The wafer bonding apparatus according to claim 1 or 2, wherein,

the adsorption areas are nested from inside to outside.

4. The wafer bonding apparatus of claim 3 wherein,

the adsorption area comprises a first adsorption area to a fourth adsorption area which are nested from inside to outside in sequence, the cross section of the first adsorption area is circular, the cross section of the second adsorption area to the fourth adsorption area is circular, the ring width of the fourth adsorption area is smaller than the ring widths of the second adsorption area and the third adsorption area and smaller than the radius of the first adsorption area, and the ring width of the second adsorption area is larger than the ring width of the third adsorption area and larger than the radius of the first adsorption area.

5. The wafer bonding apparatus of claim 2 wherein,

the pneumatic device comprises a pneumatic branch pipe and an electromagnetic valve connected with the pneumatic branch pipe, the pneumatic branch pipe is communicated with the first air hole, and the electromagnetic valve is used for controlling the size and the direction of air flow which is introduced into the first air hole.

6. The wafer bonding apparatus of claim 5, further comprising: the air pressure detection device is used for detecting the air pressure of the adsorption area;

the electromagnetic valve adjusts the air pressure of the adsorption area based on the detection result of the air pressure detection device.

7. A method of wafer bonding, comprising:

providing a wafer bonding apparatus according to any one of claims 1-6;

adjusting the pneumatic device to an adsorption mode, and sucking air into a plurality of adsorption areas so as to enable the wafer to be bonded to be adsorbed to the adsorption surface;

and adjusting the pneumatic device to a release mode, and sequentially blowing air to a plurality of adsorption areas so that the shrinkable film layer gradually releases the wafers to be bonded adsorbed on the adsorption surface.

8. The wafer bonding method according to claim 7, wherein,

the adsorption areas are nested from inside to outside;

the release mode includes: and blowing the plurality of adsorption areas in the direction from inside to outside.

9. The wafer bonding method according to claim 8, wherein the adsorption region includes a first adsorption region to a fourth adsorption region nested from inside to outside in order, a cross-sectional shape of the first adsorption region is circular in a direction parallel to the adsorption surface, and a cross-sectional shape of the second adsorption region to the fourth adsorption region is circular;

the release mode includes: sequentially performing a first stage to a fourth stage;

in the first stage, the air pressure of the first adsorption zone is adjusted to be positive pressure, the air pressure of the second adsorption zone is adjusted to be atmospheric pressure, and the air pressures of the third adsorption zone and the fourth adsorption zone are adjusted to be negative pressure;

in the second stage, the air pressures of the first adsorption zone and the second adsorption zone are adjusted to be positive pressure, the air pressure of the third adsorption zone is adjusted to be atmospheric pressure, and the air pressure of the fourth adsorption zone is adjusted to be negative pressure;

in the third stage, the air pressure from the first adsorption zone to the third adsorption zone is adjusted to be positive pressure, and the air pressure from the fourth adsorption zone is adjusted to be negative pressure;

in the fourth stage, the air pressure of the first adsorption zone to the fourth adsorption zone is adjusted to atmospheric pressure.

10. The wafer bonding method according to claim 7, wherein a plurality of the suction areas are nested inside-out;

the adsorption mode includes: and adjusting the air pressure of the innermost adsorption zone to be atmospheric pressure, and adjusting the air pressure of the rest adsorption zones to be negative pressure.