Wafer bonding equipment

Abstract

The invention provides wafer bonding equipment, and relates to the technical field of integrated circuit packaging, the wafer bonding equipment comprises an upper wafer adsorption table, the upper wafer adsorption table comprises an adsorption disc located at the bottom, the adsorption disc is provided with a plurality of adsorption units capable of working independently and a plurality of heating units capable of working independently, and the adsorption units are arranged on the adsorption disc. The adsorption units and the heating units are annularly distributed, and the multiple adsorption units and the multiple heating units are alternately arranged at intervals from the center of the upper wafer adsorption table to the periphery of the upper wafer adsorption table. According to the invention, the phenomenon of stripping caused by stress concentration in the bonding process of the wafer can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit packaging, and in particular to a wafer bonding device. Background Art

[0002] Wafer bonding is a process that combines two or more wafers together physically or chemically to form a single semiconductor device. During bonding, the atoms on the interface react to external forces to form covalent bonds that combine the two together, and the bonding interface reaches a specific bonding strength.

[0003] The bonding equipment is the core of the complete hybrid bonding process. The bond head in the bond and equipment needs to provide precise bonding force and have the ability to accurately control the physical field of the bonding process. At present, the bond head generally fixes the wafer through an adsorption part to complete the bonding. Accurate temperature and adsorption force control are essential to achieve high-quality bonding. In related technologies, the two complete wafers are generally heated throughout the entire bonding process, but continuous heating of the bonded area will cause stress concentration on the wafer, and then the bonded area will peel off, thereby affecting the bonding effect of the wafer. Summary of the invention

[0004] The problem solved by the invention is to improve the phenomenon of stress concentration and subsequent peeling of wafers during the bonding process.

[0005] In order to solve the above problems, the present invention provides a wafer bonding device, which includes an upper wafer adsorption platform, the upper wafer adsorption platform includes a adsorption plate located at the bottom, the adsorption plate is provided with a plurality of adsorption units that can work independently and a plurality of heating units that can work independently, the adsorption units and the heating units are respectively distributed in a ring shape, and the plurality of adsorption units and the heating units are alternately arranged from the center of the upper wafer adsorption platform to the periphery.

[0006] Optionally, each of the adsorption units includes a plurality of adsorption pores arranged at intervals along the circumferential direction, and each of the heating units includes a plurality of heating blocks arranged at intervals along the circumferential direction.

[0007] Optionally, the wafer bonding equipment further comprises an annular air pump, which is arranged around the outer circumference of the upper wafer adsorption platform, and each of the adsorption units is connected to the annular air pump.

[0008] Optionally, a plurality of first air channels are provided in the upper wafer adsorption platform, and the plurality of first air channels are arranged in one-to-one correspondence with the plurality of adsorption units, and each of the adsorption units is connected to the annular air pump through the first air channel;

[0009] An airway control valve is provided at each of the first airways, and the airway control valve is used to control the opening and closing of the corresponding first airway.

[0010] Optionally, the wafer bonding equipment also includes a heating power supply and a plurality of current switches, the plurality of current switches are arranged in one-to-one correspondence with the plurality of heating units, the heating power supply is electrically connected to each of the heating units, and each of the current switches is used to control the current on and off between the heating power supply and the corresponding heating unit.

[0011] Optionally, it also includes a bonding drive component and a lower wafer support platform, the upper wafer adsorption platform and the lower wafer support platform are arranged relatively to each other, and the bonding drive component is used to drive the upper wafer adsorption platform and the lower wafer support platform to approach each other.

[0012] Optionally, the wafer bonding equipment further comprises a propulsion component, and the propulsion component is used to push the center of the wafer to sag.

[0013] Optionally, the propulsion assembly includes a thrust motor and a propulsion rod, one end of the propulsion rod is connected to the propulsion motor, and the other end passes through the center of the upper wafer adsorption platform from top to bottom.

[0014] Optionally, the wafer bonding device further comprises a force sensor, which is arranged on the pushing rod and is used to detect the magnitude of the wafer bonding force in real time.

[0015] Optionally, the wafer bonding device further comprises a control system, wherein the control system is electrically connected to the airway control valve and the current switch respectively;

[0016] The control system is used to control the opening and closing of the plurality of airway control valves and the current switch, so that the plurality of adsorption units and the heating unit are closed in sequence from the center to the periphery of the upper wafer adsorption platform.

[0017] The beneficial effects of the wafer bonding equipment of the present invention are:

[0018] The embodiment of the present invention integrates a plurality of independently working adsorption units and heating units in the wafer bonding equipment. In actual operation, the upper wafer adsorption table picks up one of the wafers through the adsorption unit at the bottom, activates its surface through the heating unit, and then bonds it with another wafer. The present invention arranges the adsorption unit and the heating unit in an alternating manner in a ring shape, which not only meets the temperature control function, but also conforms to the law that the bonding wave propagates in a ring shape from the center of the wafer to the outside. In the specific bonding process, the adsorption unit at the center position stops adsorption first, so that the centers of the two wafers are in contact first, and the heating unit also stops working at the same time, and the bonding is completed at the center position first. Then, as the bonding process proceeds, the adsorption units from the center to the periphery stop adsorption one by one, and the heating units stop heating one by one until the two wafers are completely bonded. This is conducive to the zoning adjustment of the adsorption function and the heating function. The sequential suspension of the adsorption unit is conducive to the sequential bonding of the wafer from the center to the periphery to fully eliminate bubbles; the sequential suspension of the heating unit allows the non-bonding area of ​​the wafer to be fully heated and activated before bonding, while also avoiding excessive heating of the bonding area, thereby avoiding stress concentration and subsequent peeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the overall structure of a wafer bonding device in an embodiment of the present invention;

[0020] Figure 2 It is a schematic diagram of the structure of the adsorption disk in an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the internal structure of the upper wafer adsorption platform in an embodiment of the present invention;

[0022] Figure 4 Schematic diagram of the operation of the control system in the embodiment of the present invention.

[0023] Description of reference numerals:

[0024] 1. Upper wafer adsorption platform; 11. Adsorption plate; 111. Through hole; 12. Adsorption unit; 121. Adsorption air hole; 13. Heating unit; 131. Heating block; 14. First air channel; 15. Second air channel; 16. Air channel control valve; 2. Annular air pump; 3. Heating power supply; 4. Current switch; 5. Bonding drive assembly; 6. Lower wafer support platform; 7. Propulsion assembly; 71. Thrust motor; 72. Propulsion rod; 8. Force sensor; 9. Mounting frame; 10. Control system. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0026] The Z axis in the drawings represents the vertical direction, that is, the up and down position, and the positive direction of the Z axis represents the top, and the reverse direction of the Z axis represents the bottom; the X axis in the drawings represents the horizontal direction, and is designated as the front and back position, and the positive direction of the X axis represents the front side, and the reverse direction of the X axis represents the back side; the Y axis in the drawings represents the left and right position, and the positive direction of the Y axis represents the left side, and the reverse direction of the Y axis represents the right side. It should also be noted that the aforementioned Z axis, Y axis, and X axis are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0027] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0028] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0029] The wafer bonding process generally starts from the center of the two wafers and gradually spreads to the periphery, that is, the centers of the two wafers are in contact first, which is conducive to the full discharge of gas between the wafers to avoid the formation of bubbles at the bonding interface. During the wafer bonding process, the bonded area is the bonding area, and the unbonded area is called the non-bonding area. Normally, the bonding area does not need to be heated, while the non-bonding area needs to be heated continuously to activate the surfaces of the two wafers, which is conducive to the formation of intermolecular forces. At present, the two complete wafers are generally heated continuously during the entire bonding process, which will cause stress concentration in the bonding area of ​​the wafer, and then peeling will occur.

[0030] In view of the problems existing in the above-mentioned related technologies, an embodiment of the present invention provides a wafer bonding device. Figure 1 and Figure 2 As shown, the wafer bonding equipment includes an upper wafer adsorption platform 1, which includes a suction plate 11 located at the bottom. The suction plate 11 is provided with a plurality of independently working adsorption units 12 and a plurality of independently working heating units 13. The adsorption units 12 and the heating units 13 are respectively distributed in a ring shape, and the plurality of adsorption units 12 and the heating units 13 are alternately arranged from the center of the upper wafer adsorption platform 1 to the periphery.

[0031] The embodiment of the present invention integrates an adsorption unit 12 and a heating unit 13 in a wafer bonding device. In actual operation, the upper wafer adsorption platform 1 picks up one of the wafers through the adsorption unit 12 at the bottom, and after heating and activating its surface through the heating unit 13, it is bonded with another wafer. The present invention sets the adsorption unit 12 and the heating unit 13 in a ring shape, and arranges multiple adsorption units 12 and heating units 13 arranged in a ring shape alternately from the center to the periphery. While satisfying the temperature control function, it is more in line with the law that the bonding wave propagates in a ring shape from the center of the wafer to the outside. In the specific bonding process, the adsorption unit 12 at the center position stops adsorption first, so that the centers of the two wafers are in contact first, and the heating unit 13 at the center position also stops working, so that the center position completes the bonding first. Then, as the bonding process proceeds, the adsorption units 12 from the center to the periphery stop adsorption one by one, and the heating units 13 stop heating one by one until the two wafers are completely bonded. This is conducive to the zoning regulation of the adsorption function and the heating function. The sequential suspension of the adsorption unit 12 is conducive to the sequential bonding of the wafer from the center to the periphery to fully eliminate bubbles; the sequential suspension of the heating unit 13 enables the non-bonding area of ​​the wafer to be fully heated and activated before bonding and stops heating after bonding, thereby avoiding excessive heating of the bonding area and avoiding the phenomenon of peeling caused by stress concentration.

[0032] In some optional embodiments, referring to Figure 2As shown, each adsorption unit 12 includes a plurality of adsorption air holes 121 evenly spaced apart along the circumferential direction. Correspondingly, each heating unit 13 includes a plurality of heating blocks 131 evenly spaced apart along the circumferential direction.

[0033] The embodiment of the present invention divides each adsorption unit 12 into a plurality of evenly distributed adsorption pores 121, and each adsorption pore 121 is relatively independent and does not interfere with each other, which greatly improves the adsorption control ability of the adsorption plate 11 on the wafer, and improves the control accuracy of the wafer bonding process. At the same time, each heating unit 13 is also divided into a plurality of evenly distributed heating blocks 131, and each adsorption pore 121 is relatively independent and does not interfere with each other, which also greatly improves the control ability of the adsorption plate 11 on the heating temperature of the wafer, and improves the control accuracy of the wafer temperature during the wafer bonding process, which is more conducive to the phenomenon of overheating in some areas.

[0034] In some optional embodiments, referring to Figure 1 and Figure 3 As shown, the wafer bonding device further includes an annular air pump 2, which is arranged around the outer circumference of the upper wafer adsorption platform 1, and each adsorption unit 12 is connected to the annular air pump 2. Furthermore, a plurality of first air channels 14 are provided in the upper wafer adsorption platform 1, and the plurality of first air channels 14 are arranged in a one-to-one correspondence with the plurality of adsorption units 12, and each adsorption unit 12 is connected to the annular air pump 2 through the corresponding first air channel 14.

[0035] Specifically, refer to Figure 1 and Figure 3 As shown, the annular air pump 2 is arranged around the outer periphery of the upper wafer adsorption platform 1. Optionally, a second air duct 15 is also opened in the upper wafer adsorption platform 1. The second air duct 15 is arranged in the horizontal direction and is connected with the annular air pump 2, specifically extending from the annular air pump 2 to the center of the upper wafer adsorption platform 1; each first air duct 14 is arranged in the vertical direction, connecting the corresponding adsorption unit 12 and the second air duct 15, thereby realizing the connection between the adsorption unit 12 and the annular air pump 2.

[0036] In the embodiment of the present invention, each adsorption unit 12 corresponds to a first air channel 14 , which is conducive to independent control of the airflow of each adsorption unit 12 .

[0037] Further, in some optional embodiments, referring to Figure 3As shown, each first air channel 14 is provided with an air channel control valve 16, and the air channel control valve 16 is used to control the opening and closing of the corresponding first air channel 14. Specifically, each adsorption unit 12 corresponds to an air channel control valve 16, and the air channel control valve 16 is provided at the upper end of each first air channel 14 corresponding to the adsorption unit 12. The air channel control valve 16 specifically adopts a remotely controllable electric valve. When the wafer is bonded from the center to the periphery, the air channel control valve 16 corresponding to the adsorption unit 12 closest to the center can be remotely controlled to close first, and then the other air channel control valves 16 can be closed in sequence from the center to the periphery according to the bonding process.

[0038] In some optional embodiments, referring to Figure 4 As shown, the wafer bonding equipment also includes a heating power supply 3 and a plurality of current switches 4, the plurality of current switches 4 are arranged one by one with the plurality of heating units 3, the heating power supply 3 is electrically connected to each heating unit 13, and each current switch 4 is used to control the current on and off between the heating power supply 3 and the corresponding heating unit 13. Specifically, the heating block 131 can be made of a resistance material such as a resistance wire, and heat is generated by passing current through the heating block 131. When the wafer is bonded from the center to the periphery, the current switch 4 corresponding to the heating unit 13 closest to the center can be remotely cut off first, and then other current switches 4 can be closed in sequence from the center to the periphery according to the bonding process, thereby realizing independent control of each heating unit 13.

[0039] In some optional embodiments, referring to Figure 1 As shown, the wafer bonding device also includes a bonding drive component 5 and a lower wafer support platform 6. The upper wafer adsorption platform 1 and the lower wafer support platform 6 are arranged opposite to each other. The output end of the bonding drive component 5 is connected to the upper surface of the upper wafer adsorption platform 1 to drive the upper wafer adsorption platform 1 and the lower wafer support platform 6 to approach each other. Specifically, refer to Figure 1 As shown, the bonding drive assembly 5 can be a linear motor.

[0040] In some optional embodiments, referring to Figure 3 As shown, the wafer bonding device further includes a propulsion assembly 7, which is used to push the center of the wafer to sag. Figure 1 As shown, the propulsion assembly 7 includes a thrust motor 71 and a propulsion rod 72 , one end of the propulsion rod 72 is connected to the thrust motor 71 , and the other end passes through the center of the upper wafer adsorption platform 1 from top to bottom, and the bottom of the propulsion rod 72 is lower than the adsorption plate 11 .

[0041] Specifically, refer to Figure 1 and Figure 2As shown, a through hole 111 is provided at the center of the upper wafer adsorption platform 1, and a T-shaped push rod 72 passes through the through hole 111, and the lower end of the push rod 72 extends from the surface of the adsorption plate 11. When the upper wafer adsorption platform 1 adsorbs the upper wafer and moves to the top of the lower wafer support platform 6, the push rod 72 is pushed by the thrust motor 71 to feed at a low speed, thereby pushing the center of the upper wafer to contact the lower wafer first, and the upper and lower wafers are bonded due to the intermolecular force and the thrust provided by the push rod 72.

[0042] Further, refer to Figure 3 As shown, the wafer bonding device further includes a force sensor 8, which is disposed on the pushing rod 72 and can be specifically fixedly connected to the pushing rod 72 for real-time detection of the magnitude of the wafer bonding force.

[0043] In some optional embodiments, referring to Figure 1 As shown, the wafer bonding device further includes a mounting frame 9 for mounting the propulsion assembly 7 and the bonding drive assembly 5 , and the mounting frame 9 is fixedly connected to the thrust motor 71 and the bonding drive assembly 5 , respectively.

[0044] In some optional embodiments, referring to Figure 4 As shown, the wafer bonding device may further include a control system 10, and the control system 10 is electrically connected to the airway control valve 16, the current switch 4, the heating power supply 3, the thrust motor 71 and the force sensor 8. Specifically, the control system 10 is used to control the opening and closing of the plurality of airway control valves 16 and the current switch 4, so that the plurality of adsorption units 12 and the heating units 13 are closed in sequence from the center to the periphery of the upper wafer adsorption platform 1; and to adjust the heating temperature of the heating power supply 3; and to send a control signal according to the bonding force information fed back by the force sensor 8, and to adjust the thrust output by the thrust motor 71.

[0045] The present invention integrates the regulation functions of multiple physical quantities such as bonding force, heating temperature, wafer adsorption, etc. through the control system 10, and can provide multi-physical field regulation capabilities in a short bonding process, thereby improving the problems of low bonding success rate and slow response speed existing in current bonding equipment.

[0046] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A wafer bonding device, characterized in that: The invention comprises an upper wafer adsorption platform (1), wherein the upper wafer adsorption platform (1) comprises an adsorption plate (11) located at the bottom, wherein the adsorption plate (11) is provided with a plurality of adsorption units (12) capable of working independently and a plurality of heating units (13) capable of working independently, wherein the adsorption units (12) and the heating units (13) are respectively distributed in a ring shape, and the plurality of adsorption units (12) and the heating units (13) are alternately arranged from the center to the periphery of the upper wafer adsorption platform (1).

2. The wafer bonding equipment according to claim 1, characterized in that: Each of the adsorption units (12) comprises a plurality of adsorption air holes (121) arranged at intervals in the circumferential direction, and each of the heating units (13) comprises a plurality of heating blocks (131) arranged at intervals in the circumferential direction.

3. The wafer bonding equipment according to claim 1, characterized in that: The wafer bonding equipment further comprises an annular air pump (2), wherein the annular air pump (2) is arranged around the outer circumference of the upper wafer adsorption platform (1), and each of the adsorption units (12) is connected to the annular air pump (2).

4. The wafer bonding equipment according to claim 3, characterized in that: A plurality of first air channels (14) are provided in the upper wafer adsorption platform (1), the plurality of first air channels (14) are arranged in one-to-one correspondence with the plurality of adsorption units (12), and each of the adsorption units (12) is connected to the annular air pump (2) via the first air channel (14); An airway control valve (16) is provided at each of the first airways (14), and the airway control valve (16) is used to control the opening and closing of the corresponding first airway (14).

5. The wafer bonding equipment according to claim 4, characterized in that: The wafer bonding device also includes a heating power supply (3) and a plurality of current switches (4), wherein the plurality of current switches (4) are arranged in a one-to-one correspondence with the plurality of heating units (13), the heating power supply (3) is electrically connected to each of the heating units (13), and each of the current switches (4) is used to control the on-off of the current between the heating power supply (3) and the corresponding heating unit (13).

6. The wafer bonding equipment according to claim 5, characterized in that: It also includes a control system (10), wherein the control system (10) is electrically connected to the airway control valve (16) and the current switch (4) respectively; The control system (10) is used to control the opening and closing of the plurality of airway control valves (16) and the current switch (4), so that the plurality of adsorption units (12) and the heating units (13) are closed in sequence from the center to the periphery of the upper wafer adsorption platform (1).

7. The wafer bonding equipment according to claim 1, characterized in that: It also comprises a bonding drive component (5) and a lower wafer support platform (6), wherein the upper wafer adsorption platform (1) and the lower wafer support platform (6) are arranged opposite to each other in an upper and lower position, and the bonding drive component (5) is used to drive the upper wafer adsorption platform (1) and the lower wafer support platform (6) to approach each other.

8. The wafer bonding equipment according to claim 1, characterized in that: It also includes a propulsion component (7), and the propulsion component (7) is used to push the center of the wafer to sag.

9. The wafer bonding equipment according to claim 8, characterized in that: The propulsion assembly (7) comprises a thrust motor (71) and a propulsion rod (72); one end of the propulsion rod (72) is connected to the propulsion motor, and the other end passes through the center of the upper wafer adsorption platform (1) from top to bottom.

10. The wafer bonding equipment according to claim 9, characterized in that: It also comprises a force sensor (8), which is arranged on the pushing rod (72) and is used to detect the magnitude of the wafer bonding force in real time.

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