阅读说明：本技术 晶圆键合设备及方法 (Wafer bonding equipment and method ) 是由 邢程 章亚荣 马宏普 于 2021-07-27 设计创作，主要内容包括：本申请实施例提供一种晶圆键合设备及方法,所述设备包括：第一固定组件,用于固定第一晶圆；第二固定组件,用于固定第二晶圆；其中,所述第二固定组件用于固定所述第二晶圆的表面与所述第一固定组件用于固定所述第一晶圆的表面相对；加压组件,连接所述第一固定组件,用于在晶圆键合时为所述第一晶圆与第二晶圆的键合提供压力。(The embodiment of the application provides a wafer bonding device and a method, wherein the device comprises: the first fixing component is used for fixing a first wafer; the second fixing component is used for fixing a second wafer; the second fixing component is used for fixing the surface of the second wafer and is opposite to the surface of the first fixing component used for fixing the first wafer; and the pressurizing assembly is connected with the first fixing assembly and is used for providing pressure for bonding of the first wafer and the second wafer when the wafers are bonded.)

1. A wafer bonding apparatus, characterized in that the apparatus comprises:

the first fixing component is used for fixing a first wafer;

the second fixing component is used for fixing a second wafer; the second fixing component is used for fixing the surface of the second wafer and is opposite to the surface of the first fixing component used for fixing the first wafer;

and the pressurizing assembly is connected with the first fixing assembly and is used for providing pressure for bonding of the first wafer and the second wafer when the wafers are bonded.

2. The apparatus of claim 1, wherein the pressurization assembly comprises:

a gas source for providing compressed dry air CDA;

the first pneumatic valve is connected with the air source; the CDA provides pressure to the first wafer surface through the first pneumatic valve in a state where the first pneumatic valve is open.

3. The apparatus of claim 2, wherein the first securing assembly comprises:

and the first through hole is positioned on the surface of the first fixing component, is connected with the first pneumatic valve and is used for enabling the CDA to flow to the surface of the first wafer when the first pneumatic valve is opened.

4. The apparatus of claim 3, wherein the first fixture assembly comprises at least two sets of the first through holes, and each set of the first through holes is located at a corresponding position of a circumference of the first wafer with different radii.

5. The apparatus of claim 4, wherein the at least two sets of first through holes are configured to provide the CDA to the surface of the first wafer sequentially from inside to outside when the first holding assembly releases the first wafer.

6. The apparatus of claim 1, wherein the first securing assembly further comprises:

the second through hole is positioned on the surface of the first fixing component;

and the second pneumatic valve is connected with the second through hole and used for fixing or releasing the first wafer by adjusting the air pressure in the second through hole.

7. The apparatus of claim 1, wherein the first securing assembly further comprises:

the ejector pin is positioned in the center of the contact surface of the first fixing component and the first wafer; and when the thimble is in an extended state, the center of the first wafer is separated from the first fixing component.

8. The apparatus of claim 1, wherein the second securing assembly comprises:

the third through hole is positioned on the surface of the second fixing component;

and the third pneumatic valve is connected with the third through hole and used for fixing or releasing the second wafer by adjusting the air pressure in the third through hole.

9. A wafer bonding method, comprising:

fixing a first wafer and a second wafer to be bonded; the first surface of the first wafer and the second surface of the second wafer are bonding surfaces of the wafers, and the first surface is opposite to the second surface;

sequentially applying pressure to the third surface of the first wafer from inside to outside along the radius direction of the first wafer to bond the first surface and the second surface; and the third surface of the first wafer is a surface deviating from the second wafer.

10. The method of claim 9, wherein the applying pressure to the third surface of the first wafer sequentially from inside to outside along the radius of the first wafer to bond the first surface to the second surface comprises:

applying pressure to the circle center position of the third surface of the first wafer to bond the circle center of the first wafer and the area opposite to the circle center of the second wafer;

and sequentially applying pressure to the third surface of the first wafer from inside to outside along the radius direction of the first wafer, so that the first surface is bonded with the second surface.

11. The method of claim 9, wherein the applying the pressure to the third surface of the first wafer sequentially from inside to outside along the radius of the first wafer comprises:

and applying pressure to the third surface of the first wafer by sequentially providing CDA to the third surface from inside to outside along the radius direction of the first wafer.

12. The method of claim 9, wherein securing the first and second wafers to be bonded comprises:

fixing the first wafer on a fixing surface of a first fixing component in a negative pressure mode;

fixing the first wafer on a fixing surface of a second fixing component in a negative pressure mode; wherein the fixing surface of the second fixing component is opposite to the fixing surface of the first fixing component.

Technical Field

The present application relates to the field of semiconductor technology, and relates to, but is not limited to, a wafer bonding apparatus and method.

Background

Currently, in the field of semiconductor technology, the wafer-to-wafer bonding process has become a core process. The wafer bonding technology is to closely bond two polished wafers together. Specifically, two wafers to be bonded are respectively adsorbed by the upper and lower suckers, the top wafer is pushed by the ejector pin until the center of the wafer deforms and contacts with the wafer below the center, and the wafer moves from the center to the edge after bonding is formed, so that bonding is completed by using reverse tension and van der waals force.

However, in the prior art, the wafer bonding using the reverse tension and van der waals force is liable to generate bubbles, and the bonding is not tight.

Disclosure of Invention

In view of the above, embodiments of the present application provide a wafer bonding apparatus and method.

In a first aspect, an embodiment of the present application provides a wafer bonding apparatus, where the apparatus includes:

the first fixing component is used for fixing a first wafer;

the second fixing component is used for fixing a second wafer; the second fixing component is used for fixing the surface of the second wafer and is opposite to the surface of the first fixing component used for fixing the first wafer;

and the pressurizing assembly is connected with the first fixing assembly and is used for providing pressure for bonding of the first wafer and the second wafer when the wafers are bonded.

In some embodiments, the pressurization assembly comprises:

a gas source for supplying CDA (Clean Dry Air);

the first pneumatic valve is connected with the air source; the CDA provides pressure to the first wafer surface through the first pneumatic valve in a state where the first pneumatic valve is open.

In some embodiments, the first securing assembly comprises:

and the first through hole is positioned on the surface of the first fixing component, is connected with the first pneumatic valve and is used for enabling the CDA to flow to the surface of the first wafer when the first pneumatic valve is opened.

In some embodiments, the first fixing assembly includes at least two sets of the first through holes, and each set of the first through holes is located at a corresponding position of a circle of the first wafer with different radii.

In some embodiments, the at least two sets of first through holes are configured to provide the CDAs to the surface of the first wafer sequentially from inside to outside when the first holding assembly releases the first wafer.

In some embodiments, the first securing assembly further comprises:

the second through hole is positioned on the surface of the first fixing component;

and the second pneumatic valve is connected with the second through hole and used for fixing or releasing the first wafer by adjusting the air pressure in the second through hole.

In some embodiments, the first securing assembly further comprises:

the ejector pin is positioned in the center of the contact surface of the first fixing component and the first wafer; and when the thimble is in an extended state, the center of the first wafer is separated from the first fixing component.

In some embodiments, the second securing assembly comprises:

the third through hole is positioned on the surface of the second fixing component;

and the third pneumatic valve is connected with the third through hole and used for fixing or releasing the second wafer by adjusting the air pressure in the third through hole.

In another aspect, an embodiment of the present application provides a wafer bonding method, where the method includes:

fixing a first wafer and a second wafer to be bonded; the first surface of the first wafer and the second surface of the second wafer are bonding surfaces of the wafers, and the first surface is opposite to the second surface;

sequentially applying pressure to the third surface of the first wafer from inside to outside along the radius direction of the first wafer to bond the first surface and the second surface; and the third surface of the first wafer is a surface deviating from the second wafer.

In some embodiments, the applying pressure to the third surface of the first wafer from inside to outside in sequence along the radius direction of the first wafer to bond the first surface and the second surface includes:

applying pressure to the circle center position of the third surface of the first wafer to bond the circle center of the first wafer and the area opposite to the circle center of the second wafer;

and sequentially applying pressure to the third surface of the first wafer from inside to outside along the radius direction of the first wafer, so that the first surface is bonded with the second surface.

In some embodiments, the applying pressure to the third surface of the first wafer from inside to outside in sequence along the radius direction of the first wafer includes:

and applying pressure to the third surface of the first wafer by sequentially providing CDA to the third surface from inside to outside along the radius direction of the first wafer.

In some embodiments, the securing the first wafer and the second wafer to be bonded includes:

fixing the first wafer on a fixing surface of the first fixing component in a negative pressure mode;

fixing the first wafer on a fixing surface of the second fixing component in a negative pressure mode; wherein the fixing surface of the second fixing component is opposite to the fixing surface of the first fixing component.

The embodiment of the application provides wafer bonding equipment and a method, the wafer bonding equipment provides pressure for bonding a first wafer and a second wafer in a wafer bonding process through a pressurizing assembly, so that the problem of poor bonding effect caused by weak reverse tension and van der Waals force is solved, the wafer bonding strength and uniformity are improved, bubbles are reduced, and the product yield is improved.

Drawings

In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. Like reference numerals having different letter suffixes may represent different examples of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed herein.

Fig. 1 is a schematic structural diagram of a wafer bonding apparatus according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a pressing assembly according to an embodiment of the present disclosure;

FIG. 3 is an alternative schematic view of a first fastening assembly according to an embodiment of the present disclosure;

FIG. 4 is a schematic view of a mounting surface of a first mounting assembly provided in accordance with an embodiment of the present application;

FIG. 5 is an alternative schematic view of a first fastening assembly according to an embodiment of the present disclosure;

FIG. 6 is an alternative schematic structural diagram of a thimble according to an embodiment of the present disclosure;

FIG. 7 is an alternative schematic structural view of a second securing assembly provided in accordance with an embodiment of the present application;

fig. 8 is a schematic flowchart of a wafer bonding method according to an embodiment of the present disclosure.

Detailed Description

The present application will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application. Also, the embodiments described below are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from these embodiments without inventive step, are within the scope of protection of the present invention.

In a first aspect, an embodiment of the present application provides a wafer bonding apparatus, as shown in fig. 1, the apparatus includes:

a first fixing element 110 for fixing a first wafer 111;

a second fixing member 120 for fixing a second wafer 121; wherein the surface 122 of the second fixing element 120 for fixing the second wafer 121 is opposite to the surface 112 of the first fixing element 110 for fixing the first wafer 111;

and a pressure assembly 130 connected to the first fixing assembly 110 for providing pressure for bonding the first wafer 111 and the second wafer 121 during wafer bonding.

The fixing component refers to a device which keeps an object to be fixed unchanged or not moving by means of adsorption, clamping, adhesion and the like, and includes but is not limited to a sucker, a mechanical arm, a buckle and the like. In the embodiment of the present application, the first fixing component may be a mechanical sucker, which is also called a vacuum sucker or a vacuum suction nozzle, and the principle is that negative air pressure is generated in the sucker by suction of a vacuum device, so that an object to be sucked is firmly sucked. Further, the first fixing assembly may be used to adsorb the first wafer to be bonded and transfer it to the region to be bonded. In contrast, the second fixing component may be a vacuum platform, a vacuum base, or the like, and is configured to fix the second wafer to be bonded by negative pressure. The vacuum adsorption fixing assembly can reduce cost and avoid damage to the wafer in the transfer process.

It should be noted that the first wafer and the second wafer related to the embodiments of the present application need to be determined according to actual production requirements, and the wafer is used in a generic sense, that is, a silicon wafer used for manufacturing a silicon semiconductor circuit, and the original material of the wafer is silicon. The manufacturing process comprises the following steps: after the high-purity polycrystalline silicon is dissolved, the parameter silicon crystal seed crystals are slowly pulled out to form cylindrical monocrystalline silicon, and a silicon crystal bar is ground, polished and sliced to form a silicon wafer, namely a wafer.

In the embodiment of the present application, to bond the wafers, the first wafer and the second wafer need to be disposed opposite to each other, so as to perform a bonding operation between the two wafers. Illustratively, the first fixing member fixes the first wafer and has a fixing surface contacting the first wafer, and the second fixing member fixes the second wafer and has a fixing surface contacting the second wafer, so that the fixing surface of the first fixing member should be opposite to the fixing surface of the second fixing member.

The pressurizing assembly is a device for applying pressure, and can comprise a pressurizing pump, a pressurizing cylinder and the like. The pressure function here may be a pressure generated by air pressure, water pressure, or the like, or a pressure generated by direct contact of a dedicated instrument. In the embodiment of the application, the pressure required for wafer bonding is provided by the pressurizing assembly, and the pressurizing assembly can be connected with the first fixing assembly through the gas conduit. Wherein, the gas conduit is used for transporting the gas provided by the pressurizing assembly and enabling the gas to flow to the first fixing assembly.

Through above-mentioned pressure components, can increase the pressure when the wafer bonds, solved reverse tension and the weak not good problem that leads to the bonding effect of van der waals' force to can improve the dynamics and the degree of consistency of wafer bonding. Because the strength is increased, the uniformity is improved, the occurrence of bubbles during wafer bonding can be reduced, and the yield of products is improved.

In some embodiments, as shown in fig. 2, the pressing assembly 130 includes:

a gas source 131 for providing CDA;

a first pneumatic valve 132 connected to the gas source 131; in a state where the first pneumatic valve 132 is opened, the CDA provides pressure to the surface of the first wafer 111 through the first pneumatic valve 132.

The gas source is a device for providing gas and can comprise a gas pressure generating component for compressing the gas to generate gas pressure; the compressed gas processing system is used for processing the compressed gas as required; and the compressed gas distribution system distributes the processed compressed gas according to needs.

In the embodiment of the present application, the air source is used to provide clean and dry compressed air, i.e., the CDA. The CDA is obtained by drying compressed air, wherein the drying method includes but is not limited to adsorption drying, freeze drying, deliquescence drying, and membrane permeation drying.

The pneumatic valve is a valve for adjusting the flow of compressed air and can be composed of an execution part and an adjusting part. Illustratively, the actuating member is a thrust member of the pneumatic valve, which generates a corresponding thrust force according to the magnitude of the pressure indicated by the control signal, thereby pushing the actuation of the pneumatic valve adjusting member. The regulating member of the pneumatic valve comprises a valve body which is in direct contact with the compressed gas, thereby regulating the flow rate of the gas.

In the embodiment of the present application, the first pneumatic valve is connected to the gas source through a gas conduit, and it should be noted that the gas conduit should not affect the CDA. Illustratively, when the modulating component of the first pneumatic valve is open, the CDA may pass through the valve body, thereby continuing to flow to the first wafer surface and providing pressure to the surface of the first wafer; when the regulating member of the first pneumatic valve is closed, the CDA cannot pass through the valve body. Here, in a state where the first pneumatic valve is opened, CDA flows to the first wafer surface so that the gas pressure per unit area is increased, thereby generating pressure on the first wafer surface.

The gas source, the first pneumatic valve and the gas conduit in the embodiment of the present application play roles in communicating, transporting and adjusting the CDA, and can provide the pressure required by wafer bonding to the first wafer on the premise of lower cost. Moreover, the method can not cause mechanical damage to the wafer.

In some embodiments, as shown in fig. 3, the first fixing assembly 110 includes:

a first through hole 113, located on the surface of the first fixing element 110, connected to the first pneumatic valve 132, for allowing the CDA to flow toward the surface of the first wafer 111 in a state where the first pneumatic valve 132 is opened.

In the embodiment of the present application, the first through hole is a gas hole located on the surface of the first fixing component, and is used for realizing the circulation of gas. Here, the first through hole is connected to the first pneumatic valve in the above embodiments, so as to provide CDA to the surface of the first wafer, and thus, when the first pneumatic valve is turned on, CDA blows air to the surface of the first wafer through the first through hole, thereby providing a pressure required for bonding.

In some embodiments, the first through hole may extend through the first fastening assembly, or may be located within the first fastening assembly. One end of the first through hole is positioned on the fixing surface of the first fixing component and faces to the surface of the first wafer no matter the shape or the length of the first through hole; the other end is connected with the first pneumatic valve.

It should be noted that the number of the first through holes may be plural, and the first through holes may be uniformly distributed on the fixing surface of the first fixing element, so as to provide uniform air pressure for the first wafer.

In some embodiments, fig. 4 is a schematic view of the mounting surface 114 (i.e., the surface in contact with the first wafer) of the first mounting assembly. As shown in fig. 4, the first fixing assembly includes at least two sets of the first through holes 113, and the first through holes 113 of each set are respectively located at corresponding positions on the fixing surface 114 of the circumferences of the first wafer with different radii.

For example, the first fixing component may include at least two sets of the first through holes, each set having a plurality of first through holes (the number of the first through holes in different sets may be the same or different), and each set of the first through holes is located at a position corresponding to the circumference of the different concentric circles. For example, the number of the first group of the first through holes is 4, and the first through holes are positioned on the circumferential position closer to the circle center and are uniformly distributed; the number of the second group of first through holes is 8, and the second group of first through holes are located on the circumferential position relatively far away from the circle center and are uniformly distributed.

The corresponding position means that the first through hole is located in a direction perpendicular to the surface of the wafer, and a projection of the center of the through hole in the direction falls on a circumference of a concentric circle of the surface of the wafer. Therefore, the first through holes of different groups are located at different corresponding positions of the first wafer.

In some embodiments, the at least two sets of first through holes are configured to provide the CDAs to the surface of the first wafer sequentially from inside to outside when the first holding assembly releases the first wafer.

In the embodiment of the present application, the first fixing member may be a vacuum chuck having a function of fixing and releasing the first wafer. The air pressure inside and outside the sucker can be adjusted by pumping and blowing air through vacuum equipment. When the air pressure inside and outside the chuck is close to balance, the first wafer can be released.

Further, in the embodiment of the present application, a plurality of groups of corresponding first through holes are distributed along a radial direction of the surface of the first wafer. The CDA is provided to the first wafer surface sequentially from inside to outside, i.e., radially from the center to the circumferential direction. Here, the CDA directly contacts the first wafer surface, and since the pressure of the gas is increased with the area unchanged, the pressure applied to the first wafer surface is generated. And the flow and rate of the CDA can be artificially controlled.

The CDA is sequentially provided from inside to outside in the embodiment of the application, so that the wafers are sequentially bonded from the circle center to the outside, and the generation of bubbles is effectively reduced.

In some embodiments, as shown in fig. 5, the first fixing assembly 110 further includes:

a second through hole 115 located on the surface of the first fixing component 110;

and a second pneumatic valve 116 connected to the second through hole 115 for fixing or releasing the first wafer 111 by adjusting the air pressure in the second through hole 115.

The second through hole is also illustratively an air hole located in the surface of the first fixing member (i.e., the above-described fixing surface). Here, the second through hole is connected to a second pneumatic valve through a gas conduit for allowing gas to flow in or out when the vacuum apparatus evacuates or blows gas, thereby changing the gas pressure in the second through hole. Specifically, in the state that the second pneumatic valve is opened, the vacuum equipment exhausts air to reduce the air pressure in the second through hole, so that negative air pressure can be generated and used for fixing the first wafer; and under the state that the second pneumatic valve is opened, the vacuum equipment blows air to increase the air pressure in the second through hole, so that the air pressure difference can be balanced and the first wafer can be released.

It should be noted that in some embodiments, the second via may be the same set of vias as the first via, i.e., both the suction and blowing through the via can be used to fix or release the first wafer and the CDA can be flowed to the surface of the first wafer through the via. Specifically, the second pneumatic valve is opened, the first pneumatic valve is closed, and the first wafer is fixed on the first fixing assembly through negative air pressure inside and outside the through hole; when the wafer is bonded, the second pneumatic valve is closed, the first starting valve is opened, the first wafer is released under the self gravity, and the CDA applies pressure to the surface of the first wafer through the through hole; after bonding is complete, the first pneumatic valve is closed. Here, the gas conduits of the first and second pneumatic valves connected to the through-hole may share a portion, thereby saving costs.

In addition, the second pneumatic valve and the first pneumatic valve in the pressurizing assembly can be the same pneumatic valve, and the pneumatic valve can provide negative pressure through air suction on one hand, and can also provide CDA to the surface of the first wafer to enable the first wafer to be released and further subjected to the action of air pressure to realize bonding.

In other embodiments, the second through hole is not shared with the first through hole, that is, the second pneumatic valve and the first pneumatic valve are respectively connected with the second through hole and the first through hole through different gas conduits, and there is no part shared by the gas conduits, and each part works independently before, and the wafer bonding process is completed.

In some embodiments, as shown in fig. 6, the first fixing assembly 110 further includes:

a thimble 117 located at the center of the contact surface between the first fixing element 110 and the first wafer 111; in the extended state of the thimble 117, the center of the first wafer 111 is separated from the first fixing element 110.

The thimble in the embodiment of the application can comprise a needle body and a needle head, wherein the needle body part can be extended or shortened to adjust the thimble, the needle head is a part directly contacted with a workpiece, and the needle head can generate pressure through direct contact to push the workpiece to move.

In the embodiment of the application, the needle head part of the thimble adopts a relatively flat surface. For example, the center of the contact surface of the first fixing element and the first wafer may be the center of the first wafer, and the needle of the thimble directly contacts the center of the first wafer by extending the thimble, so as to generate a pressure to push the first wafer away from the first fixing element. Further, due to the action of the ejector pin, the first wafer is deformed, and therefore the tension of the first wafer is changed. Under the state that the center of the first wafer is separated and the edge of the first wafer is fixed, the generated reverse tension and van der Waals force when the wafers are contacted can bond the first wafer and the second wafer.

It should be noted that in the embodiment of the present application, the auxiliary pressure may be provided by the pressing component on the premise that the ejector pin provides the pressure, and on the other hand, the pressing component may be directly used to generate a pressure greater than the reverse tension and the van der waals force without using the ejector pin, so as to achieve the bonding of the wafer.

In some embodiments, as shown in fig. 7, the second fixing assembly 120 includes:

a third through hole 123 located on the surface of the second fixing component 120;

and a third pneumatic valve 124 connected to the third through hole 123 for fixing or releasing the second wafer 121 by adjusting the air pressure in the third through hole 123.

In an embodiment of the present invention, the second fixing assembly may be a susceptor for fixing a second wafer. Specifically, the second fixing member has a gas hole similar to the second through hole, i.e., a third through hole, on a surface thereof, which functions similarly to the second through hole, and is connected to the third pneumatic valve through a gas conduit. When the third pneumatic valve is opened, negative air pressure can be generated inside and outside the bearing table by pumping air through vacuum equipment, so that the second wafer is fixed; and in the state that the third pneumatic valve is opened, air is blown through vacuum equipment, so that the air pressure inside and outside the bearing table is close to balance, the second wafer is released, and then the second wafer is moved out of the second fixing assembly by using devices such as a mechanical arm and the like.

In another aspect, an embodiment of the present application provides a wafer bonding method, as shown in fig. 8, the method includes:

step S801, fixing a first wafer and a second wafer to be bonded; the first surface of the first wafer and the second surface of the second wafer are bonding surfaces of the wafers, and the first surface is opposite to the second surface;

step S802, sequentially applying pressure to a third surface of the first wafer from inside to outside along the radius direction of the first wafer, so that the first surface is bonded with the second surface; and the third surface of the first wafer is a surface deviating from the second wafer.

The device for fixing the wafer includes, but is not limited to, a suction cup, a robot, a latch, a susceptor, etc., and after the wafer is moved from the outside of the bonding apparatus to the inside of the bonding apparatus, the wafer is kept unchanged or not moved during the bonding process by the fixing component.

The wafer related to the embodiment of the present application may be a cylindrical structure, and has a side surface and two upper and lower surfaces, where the upper surface and the lower surface are two surfaces of the same wafer that face away from each other. Specifically, the first surface and the third surface of the first wafer face away from each other, and the second surface and the fourth surface of the second wafer face away from each other. When the wafers are bonded, the first wafer and the second wafer are bonded oppositely, and at this time, the first surface of the first wafer and the second surface of the second wafer are bonding surfaces, that is, the first surface is opposite to the second surface.

In the embodiment of the present application, the third surface of the first wafer is circular, and any direction extending outward from the center of the circle to the circumference is a radial direction. Further, pressure needs to be applied sequentially from inside to outside, i.e. from the center of the circle to the circumference, where the sequential means that after pressure is applied to the center area, pressure is applied to the surface away from the center of the circle along the radial direction.

The pressure involved in the embodiments of the present application is a kind of elastic force, and needs to contact the third surface of the first wafer and deform the first wafer, including but not limited to gas pressing, mechanical pressing, liquid pressing, and the like. When applying the pressure, the processes are required to be sequentially performed from inside to outside along the radius direction of the first wafer.

During bonding, the first surface of the first wafer serves as a bonding surface, and a third surface opposite to the first surface is used for receiving pressure, and the third surface is a surface facing away from the second wafer because the first wafer and the second wafer are opposite.

The wafer bonding method provided by the embodiment of the application can provide larger and more uniform bonding force in the bonding process, and can effectively reduce the generation of bubbles, thereby improving the yield of products.

In some embodiments, the applying pressure to the third surface of the first wafer from inside to outside in sequence along the radius direction of the first wafer to bond the first surface and the second surface includes:

applying pressure to the circle center position of the third surface of the first wafer to bond the circle center of the first wafer and the area opposite to the circle center of the second wafer;

and sequentially applying pressure to the third surface of the first wafer from inside to outside along the radius direction of the first wafer, so that the first surface is bonded with the second surface.

In the bonding process, the first surface of the first wafer and the second surface of the second wafer are bonded, and the first surface and the second surface are both circular, so that the centers of the two surfaces are opposite. For example, the center of the circle of the first surface, the center of the circle of the second surface, and the center of the circle of the third surface are all located on the same straight line, and pressure is applied to the position of the center of the circle of the third surface of the first wafer, so that the first wafer deforms. When the applied pressure is sufficiently large, the center of the first surface of the first wafer may bond with the center region of the second surface of the second wafer.

Further, after the bonding of the circle center regions of the two wafers is completed, pressure is sequentially applied to each radius direction of the circumference along the circle center, and other regions of the first surface of the first wafer are bonded with corresponding regions of the second surface of the second wafer in a diffusion mode.

According to the embodiment of the application, the circle center area is bonded first, and other areas are bonded in sequence from inside to outside along the radius direction, so that bubbles can be effectively reduced, and the yield of finished products is greatly improved.

In some embodiments, the applying pressure to the third surface of the first wafer from inside to outside in sequence along the radius direction of the first wafer includes:

and applying pressure to the third surface of the first wafer by sequentially providing CDA to the third surface from inside to outside along the radius direction of the first wafer.

The pressure is provided in the embodiment of the present application by gas compression, i.e., CDA is provided, so that CDA flows to the area to be pressed on the third surface of the first wafer, where CDA directly contacts the surface of the area, and the pressure required for bonding is generated by the increase of pressure per unit area.

The method for applying the pressure is simple, and additional mechanical damage to the wafer can not be caused.

In some embodiments, the securing the first wafer and the second wafer to be bonded includes:

fixing the first wafer on a fixing surface of a first fixing component in a negative pressure mode;

fixing the first wafer on a fixing surface of a second fixing component in a negative pressure mode; wherein the fixing surface of the second fixing component is opposite to the fixing surface of the first fixing component.

Before bonding, the wafer needs to be fixed in a manner including, but not limited to, adsorption, clamping, and carrying. In the embodiment of the application, the first wafer and the second wafer are respectively fixed on the fixing surfaces of the first fixing component and the second fixing component in a negative pressure mode, wherein the negative pressure refers to a gas pressure state lower than normal pressure caused on the opposite surfaces of the fixing components, so that pressure difference is generated inside and outside the fixing components, and the wafers are fixed on the fixing surfaces.

In the bonding process, the first wafer and the second wafer are bonded oppositely, so that when the first wafer and the second wafer are fixed, the fixing surface of the first fixing component is opposite to the fixing surface of the first fixing component.

The negative pressure mode can reduce the cost required during bonding, and can not cause additional mechanical damage to the wafer.

The features disclosed in the several method or apparatus embodiments provided in the present application may be combined arbitrarily, without conflict, to arrive at new method embodiments or apparatus embodiments.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.