wafer bonding equipment

Abstract

The present invention provides a wafer bonding device, comprising: an adsorption device, arranged below a first wafer and a second wafer, the second wafer being located above the first wafer; an air blowing ejector pin, arranged above the second wafer, for blowing air toward the middle area of ​​the second wafer at a position not contacting the second wafer, so that the first wafer and the second wafer are bonded under the pressure generated by the air blowing. The present invention can completely solve the deformation problem of the wafer caused by the force during the bonding process, improve the bonding accuracy and bonding quality, and realize the metal interconnection technology between wafers in the true sense. The present invention can have good compatibility with the currently used hybrid bonding machine and has good practical application value.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor equipment design, and in particular relates to a wafer bonding device. Background Art

[0002] Wafer bonding technology refers to the process of tightly bonding two mirror-polished homogeneous or heterogeneous wafers together through chemical and physical effects. After the wafers are bonded, the atoms on the interface react under the action of external forces to form covalent bonds to combine them into one, and the bonding interface reaches a specific bonding strength.

[0003] In the field of MEMS and IC manufacturing, the bonding process plays an important role. Traditional silicon-silicon bonding uses pattern recognition and lens alignment mode to make the upper and lower silicon wafers overlap, and then directly bond. In the actual process operation of this model, due to factors such as the warping of the silicon wafer itself, it is difficult for the gas to be discharged from the inside of the silicon wafer during the bonding process and it will affect the alignment accuracy. Typically, there will be more bubbles or poor alignment accuracy, which will affect the product yield, and in extreme cases, even scrap the product.

[0004] The usual solution is to control the quality of the silicon wafers coming in from the previous process, and to keep the warpage of the silicon wafers within a certain range before bonding. However, this will invisibly define a clear control for other processes, making it impossible to build many structures, and greatly increasing the production cost of the product.

[0005] In the field of MEMS and IC manufacturing, in order to meet the growing demand and overcome the limitations of Moore's Law, multi-chip stacking has been proposed as a solution by the industry. With the application of advanced packaging technology, 2.5D stacking uses the development and application of silicon through-hole via technology. Nowadays, the vertical expansion of wafers is becoming more and more important in the so-called 3D stacking, and hybrid bonding technology between silicon wafers is considered to be the best solution for achieving permanent bonding.

[0006] In actual process operations, the current hybrid bonding machine uses a high-precision alignment system to align the upper and lower wafers. Then, a top pin of the machine applies external pressure to the upper wafer, allowing the two wafers to contact from the center. The hydrogen bonds then quickly spread to the surrounding areas, completing high-precision pre-bonding of the two wafers in the group.

[0007] However, this process has an obvious disadvantage, that is, the external pressure will change the morphology of the upper wafer, especially the stress point will produce a deformation that is difficult to recover, resulting in a slight gap between the pre-bonded wafers and affecting the alignment accuracy. This deformation is more obvious for thin substrates. Summary of the invention

[0008] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a wafer bonding device for solving the deformation problem caused by the stress process of semiconductor wafer pre-bonding in the prior art, as well as the problem of how to reduce the deformation and improve the bonding accuracy.

[0009] To achieve the above-mentioned purpose and other related purposes, the present invention provides a wafer bonding device, which includes: an adsorption device, arranged below a first wafer and a second wafer, and the second wafer is located above the first wafer; an air blowing pin, arranged above the second wafer, and used for blowing toward the middle area of ​​the second wafer at a position not contacting the second wafer, so that the first wafer and the second wafer are bonded under the pressure generated by the blowing.

[0010] Optionally, the blowing ejector pin includes a plurality of blowing holes, and the pressure generated by each blowing hole is independently adjustable, and the pressure generated by each blowing hole is adjusted according to the alignment data of the first wafer and the second wafer to reduce the deformation and extension of the middle area of ​​the second wafer.

[0011] Optionally, an alignment measurement module is also included for obtaining alignment data of the first wafer and the second wafer, wherein the alignment data includes deformation and elongation data of the force-bearing area after wafer bonding, and the alignment data is stored and fed back to the wafer bonding device.

[0012] Optionally, the blowing pin is provided with a vertical motion device, and when the blowing pin blows air over the middle area of ​​the second wafer, the distance between the blowing pin and the second wafer is 2-3 mm.

[0013] Optionally, the wafer bonding equipment also includes: a photosensitive ranging device, arranged above the first wafer and the second wafer, for determining the distance distribution between the first wafer and the photosensitive ranging device, and determining the distance distribution between the second wafer and the photosensitive ranging device by receiving and feeding back optical signals, so as to obtain a first warping distribution value of the first wafer and a second warping distribution value of the second wafer; an adsorption device, arranged below the first wafer, the adsorption device including a plurality of adsorption units to quantitatively compensate for the deformation amount of the first wafer. The adsorption device applies an adsorption force from the bottom of the first wafer to the first wafer according to the adsorption value to be compensated for the first wafer, so as to quantitatively compensate for the deformation amount of the first wafer, so that the bonding surfaces of the first wafer and the second wafer remain relatively parallel.

[0014] Optionally, the photosensitive ranging device is also used to obtain the deformation amount that needs to be changed in each area of ​​the first wafer based on the first warpage distribution value and the second warpage distribution value of the second wafer; the adsorption device controls the adsorption force of the corresponding area based on the deformation amount that needs to be changed, so as to quantitatively compensate for the deformation amount of the first wafer, so that the bonding surfaces of the first wafer and the second wafer remain relatively parallel.

[0015] Optionally, the adsorption force is obtained by the following formula:

[0016] F = k△x + B;

[0017] Wherein, F is the adsorption force, k is the elastic constant of the second wafer, and B is a fixed constant.

[0018] Optionally, the adsorption device includes a vacuum suction cup, and the surface of the vacuum suction cup has multiple adsorption holes. The adsorption force of the adsorption holes is adjusted by setting the vacuum degree of the vacuum suction cup and the aperture of the adsorption holes, wherein the magnitude of the adsorption force is positively correlated with the vacuum degree and negatively correlated with the aperture of the adsorption holes.

[0019] Optionally, the vacuum suction cup includes a plurality of vacuum cavities, each vacuum cavity is correspondingly provided with one or more adsorption holes, and the vacuum degree in each vacuum cavity is independently adjustable to control the adsorption force of the corresponding area.

[0020] Optionally, the shape of the adsorption hole includes one of a circular hole, an arc hole and a ring hole.

[0021] As described above, the wafer bonding device of the present invention has the following beneficial effects:

[0022] During the operation of the bonding machine, the present invention changes the force-bearing ejector pin into a multi-hole blowing ejector pin, so that the bonding process changes from hard contact to soft contact, and overcomes the problem of deformation of the wafer due to force. The present invention adopts a multi-hole blowing mode and an internal feedback measurement mechanism of the machine, which can effectively compensate for the accuracy and rotation deviation of the middle area of ​​the wafer, and finally achieve the effect of improving the bonding quality. The present invention can completely solve the deformation problem of the wafer caused by force during the bonding process, improve the bonding accuracy and bonding quality, and realize the metal interconnection technology between wafers in the true sense. The present invention can be well compatible with the currently used hybrid bonding machine and has good practical application value.

[0023] According to the warpage distribution of the upper and lower wafers, the present invention connects corresponding vacuum adsorption holes to different areas of the lower chuck, and mechanically changes the warpage condition of the bottom wafer by controlling the adsorption values ​​of the adsorption holes in different areas, so that the upper and lower wafers are in a relatively parallel state, so that during the wafer force bonding process, bubbles and alignment accuracy errors are greatly reduced, thereby improving the bonding process quality.

[0024] The present invention installs a photosensitive distance measuring device inside the bonding machine, and connects different adsorption holes in different areas of the lower chuck. The warpage distribution of the wafer is calculated by simulating the inside of the machine, and the adsorption value is changed accordingly during the bonding process. The present invention has good compatibility with the bonding machine, can also be widely used in multi-layer bonding, and has good practical application value.

[0025] The use of the equipment and method of the present invention can completely solve the problems of wafer warping and wafer deformation during bonding, and can effectively reduce production costs and process complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Shown is a schematic structural diagram of a wafer bonding device according to an embodiment of the present invention.

[0027] Figure 2 Shown is a schematic structural diagram of an adsorption device of a wafer bonding device according to an embodiment of the present invention.

[0028] Figure 3 Shown is a schematic diagram of the principle of obtaining wafer warpage distribution values ​​by a wafer bonding device according to an embodiment of the present invention.

[0029] Figure 4 It is a schematic diagram showing the principle of quantitatively compensating the deformation amount of the wafer by the wafer bonding equipment according to an embodiment of the present invention.

[0030] Figure 5 Shown is a schematic diagram of the blowing hole distribution structure of the blowing pin of the wafer bonding equipment according to an embodiment of the present invention.

[0031] Figure 6 A schematic diagram showing data of measuring deformation and elongation of a wafer stress-bearing area after bonding according to an embodiment of the present invention.

[0032] Figure 7 It is a schematic diagram showing that the wafer bonding equipment of an embodiment of the present invention compensates according to the wafer data and effectively reduces the deformation and extension of the wafer in the central force-bearing area by adjusting the alignment data and the gas volume of different gases in the blowing holes.

[0033] Figure 8 The schematic diagram shows that the air blowing pin of the wafer bonding equipment according to the embodiment of the present invention can effectively make the wafer be subjected to uniform force, thereby causing regular deformation.

[0034] Fig. 9 It is a schematic diagram showing that a conventional machine applies external pressure to an upper wafer through a top pin, and the externally applied pressure changes the morphology of the upper wafer.

[0035] Component number description

[0036] 101 Photosensitive ranging device

[0037] 102 Adsorption device

[0038] 103 First Wafer

[0039] 104 Second Wafer

[0040] 105 The first wafer after quantitative compensation of deformation

[0041] 106 adsorption holes

[0042] 1061 Round Hole

[0043] 1062 Annular hole

[0044] 1063 Arc hole

[0045] 20 Blowing ejector pin

[0046] 201 Blowing hole

[0047] 30 Ejector DETAILED DESCRIPTION

[0048] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0049] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic view is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional space dimensions of length, width and depth should be included.

[0050] For ease of description, spatially relative terms such as "under," "below," "below," "below," "above," "on," etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0051] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0052] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0053] The traditional bonding machine generally uses super-large pressure to change the warpage value of the wafer to reduce warpage, but this mode will cause the wafer itself to be deformed under pressure, affecting the bonding accuracy. The purpose of the present invention is to install a photosensitive ranging device 101 inside the bonding machine to simulate the warpage and distribution of the wafer during the bonding process, and then feed back to the bonding machine. According to the warpage distribution of the upper and lower wafers, the bonding machine gives different adsorption strengths to the bottom wafer in different regions during the force process of the bonding process, quantitatively changes the warpage value of the bottom wafer, and makes it close to the warpage distribution of the top wafer, and finally allows the two wafers to maintain a relatively parallel distribution.

[0054] Furthermore, the current hybrid wafer direct bonding technology has an accuracy of up to 50nm, so a slight deformation of the wafer will affect the bonding effect. Traditionally, a pin 30 on the machine applies external pressure to the upper wafer, such as Fig. 9 As shown, the two wafers are brought into contact from the center, and then rapidly spread to the surroundings through hydrogen bonding, completing high-precision pre-bonding of the two wafers in the group. However, this process has an obvious disadvantage, that is, the external pressure will change the morphology of the upper wafer, especially the stress point will produce deformation that is difficult to recover, resulting in a slight gap between the pre-bonded wafers and affecting the alignment accuracy. This deformation is more obvious for thin substrates.

[0055] The present invention measures the warpage distribution of two wafers and calculates the deformation that the bottom wafer needs to make. For wafers with the same process, the strain in the vertical direction approximately satisfies a linear relationship, and the corresponding bonding machine production program is written, which can be targeted to compensate for the different warpages of the incoming wafers, so that they can always maintain a horizontal state during the bonding process, thereby improving the quality of the bonding process. Then, after the bonding machine alignment system completes the pre-alignment, the wafer is subjected to external force for pre-bonding. At this time, it is only necessary to change the external force applied to the wafer by the outside world in direct contact to the airflow controlled by the pneumatic valve, and reduce the deformation of the wafer through the air blowing force model, thereby overcoming the accuracy problem in the bonding force process. And because the force application process occurs in a normal temperature and pressure environment, the use of the air blowing force model will not have a negative impact on the bonding process.

[0056] like Figure 1 and Figure 8 As shown, this embodiment provides a wafer bonding device, which includes: a photosensitive distance measuring device 10, an adsorption device 102 and an air blowing ejector pin.

[0057] The adsorption device 102 is disposed below the first wafer 103 and the second wafer 104 , and the second wafer 104 is located above the first wafer 103 .

[0058] like Figure 8 As shown, the blowing pin 20 is disposed above the second wafer 104 and is used to blow air toward the middle area of ​​the second wafer 104 without contacting the second wafer 104, so that the first wafer 103 and the second wafer 104 are bonded under the pressure generated by the blowing.

[0059] like Figure 5 As shown, the blowing ejector pin 20 includes a plurality of blowing holes 201, and the pressure generated by each blowing hole 201 is independently adjustable. The pressure generated by each blowing hole 201 is adjusted according to the alignment data of the first wafer 103 and the second wafer 104 to reduce the deformation and extension of the middle area of ​​the second wafer 104. The blowing ejector pin 20 is equipped with a vertical motion device, and when the blowing ejector pin blows air over the middle area of ​​the second wafer 104, the distance between the blowing ejector pin 20 and the second wafer 104 is 2 to 3 mm.

[0060] The present invention uses a blowing hole blowing mode to apply pressure, replacing the current local hard contact of the force-applying ejector pin, to avoid the upper wafer receiving local hard force, which causes excessive deformation of the force-applying point area. The gas of the blowing ejector pin can be nitrogen, and the blowing ejector pin can use a square of 2cm×2cm or a circular force-applying area of ​​about 2cm in diameter (consistent with the force-applying area of ​​the traditional force-applying ejector pin), the blowing hole is 2mm×2mm (about 50 holes), and the gas volume of the blowing hole can be set separately. Therefore, the use of the blowing mode can effectively make the wafer evenly stressed, thereby causing regular deformation, such as Figure 8 As shown, it is ensured that the upper and lower wafers are bonded in an orderly manner during the bonding process.

[0061] The wafer bonding device further includes an alignment measurement module for obtaining alignment data of the first wafer 103 and the second wafer 104, wherein the alignment data includes deformation and elongation data of the force-bearing area after wafer bonding, such as Figure 6 As shown, the alignment data is stored and fed back to the wafer bonding equipment.

[0062] In addition, after the wafer is bonded, it is transferred to the alignment measurement module to measure the deformation and elongation data of the wafer stress area after bonding, such as Figure 6 As shown, the alignment and blowing system can then be fed back based on this data. According to the rule that the states of the same batch of wafers are roughly the same, the wafer bonding equipment can compensate based on the data of this wafer by adjusting the alignment data and the gas volume of different gases in the blowing hole 201, such as Figure 7As shown, the deformation and extension of the wafer in the central force-bearing area are effectively reduced, the alignment accuracy and electrical contact in the hybrid bonding mode are ensured, and the metal interconnection in the true sense is realized.

[0063] The photosensitive ranging device 101 is arranged above the first wafer 103 and the second wafer 104, and is used to determine the distance distribution between the top surface of the first wafer 103 and the photosensitive ranging device 101, and determine the distance distribution between the top surface of the second wafer 104 and the photosensitive ranging device 101 through the reception and feedback of optical signals, so as to obtain a first warping distribution value of the first wafer 103 and a second warping distribution value of the second wafer 104, and the second wafer 104 is located above the first wafer 103.

[0064] For example, the photosensitive distance measuring device 101 includes a photosensitive distance measuring chuck, which emits light to the wafer below and then reflects it. When the wafer is warped, there are differences in the reflected light signals at different positions. The photosensitive distance measuring chuck determines the distance distribution between the top surface of the wafer and the photosensitive distance measuring chuck based on the difference, thereby obtaining the warpage distribution value of the wafer, such as Figure 3 shown.

[0065] During application, it is only necessary to fix the photosensitive ranging chuck on the upper part of the interior of the wafer bonding device through detachable connectors such as screws. It can be powered by a power supply line of the wafer bonding device, or it can be powered by its own battery. It can be connected to the adsorption device 102 by wire or wireless means to achieve signal connection between it and the adsorption device 102.

[0066] Furthermore, in this embodiment, the photosensitive distance measuring device 101 is also used to obtain the deformation amount that needs to be changed in each area of ​​the second wafer 104 according to the first warpage distribution value and the second warpage distribution value of the second wafer 104.

[0067] like Figure 1 to Figure 4 As shown, the adsorption device 102 is arranged below the first wafer 103, and the adsorption device 102 includes a plurality of adsorption units. The adsorption device 102 applies adsorption force from the bottom of the first wafer 103 to the first wafer 103 according to the adsorption value that needs to be compensated for the first wafer 103, so as to quantitatively compensate for the deformation of the first wafer 103, and obtain the second wafer 105 after the quantitative compensation for the deformation, so that the bonding surfaces of the first wafer 103 and the second wafer 104 remain relatively parallel.

[0068] In this embodiment, the adsorption device 102 controls the adsorption force of the corresponding area based on the deformation amount that needs to be changed fed back by the photosensitive ranging device 101, so as to quantitatively compensate for the deformation amount of the first wafer 103, so that the bonding surfaces of the first wafer 103 and the second wafer 104 remain relatively parallel.

[0069] In this embodiment, the adsorption force is obtained by the following formula: F=k△x+B; wherein F is the adsorption force, k is the elastic constant of the first wafer 103, and B is a fixed constant. For wafers of the same process, the strain in the vertical direction approximately satisfies a linear relationship, and the bonding equipment production program is written accordingly, so that targeted compensation can be made for different warpages of the incoming wafers, so that they can always maintain a horizontal state during the bonding process, thereby improving the quality of the bonding process.

[0070] like Figure 1 and Figure 2 As shown, the adsorption device 102 includes a vacuum suction cup, and a plurality of adsorption holes 106 are provided on the surface of the vacuum suction cup. The adsorption force of the adsorption holes 106 is adjusted by setting the vacuum degree of the vacuum suction cup and the aperture of the adsorption holes 106 , wherein the magnitude of the adsorption force is positively correlated with the vacuum degree, and negatively correlated with the aperture of the adsorption holes 106 .

[0071] In order to further adapt to the warpage distribution of the wafer in different areas, in this embodiment, the vacuum chuck includes a plurality of vacuum chambers, each of which includes one or more adsorption holes 106, and the vacuum degree in each vacuum chamber is independently adjustable to control the adsorption force of the corresponding area. In this example, different adsorption strengths are given to the bottom wafer in different areas, and the warpage value of the bottom wafer is quantitatively changed to make it close to the warpage distribution of the top wafer, so as to finally keep the two wafers in a relatively parallel distribution.

[0072] Since wafer warping is generally more severe at the edges of the wafer and less severe in the middle region, in a specific implementation process, the density of the adsorption holes 106 of the adsorption device 102 corresponding to the edge region of the first wafer 103 is greater than the density of the adsorption holes 106 located in the middle region of the first wafer 103, and the aperture size of the adsorption holes 106 of the adsorption device 102 corresponding to the edge region of the first wafer 103 is smaller than the aperture size of the adsorption holes 106 located in the middle region of the first wafer 103.

[0073] The shape of the adsorption hole 106 includes a circular hole 1061, an arc hole 1063 and an annular hole 1062. Figure 2As shown, of course, the shape of the adsorption hole 106 can also be a rectangle, a triangle, a rhombus, an ellipse, etc., and is not limited to the examples listed here. In this embodiment, the adsorption hole 106 located inside the adsorption device 102 is a circular hole 1061, the adsorption hole 106 located in the middle of the adsorption device 102 is an annular hole 1062, and the adsorption hole 106 located at the edge of the adsorption device 102 is an arc hole 1063. Furthermore, the circular hole 1061 inside the adsorption device 102, the annular hole 1062 in the middle, and the arc hole 1063 at the edge are all provided with independent vacuum chambers, so that the adsorption force of the adsorption holes 106 in each area can be independently adjusted. This configuration is more widely applicable to improving wafer warpage, and can cope with deformation compensation for most wafer warpages. Therefore, in most cases, deformation compensation for wafer warpage can be achieved without replacing the adsorption device 102, which can effectively save costs.

[0074] like Figure 1 to Figure 4 As shown, this embodiment also provides a wafer bonding method for eliminating wafer warpage, including:

[0075] Step 1), providing a wafer bonding device as described in any one of the above;

[0076] Step 2), placing the first wafer 103 in the wafer bonding device, based on the photosensitive ranging device 101, by receiving and feeding back optical signals, determining the distance distribution between the top surface of the first wafer 103 and the photosensitive ranging device 101, thereby obtaining a first warpage distribution value of the first wafer 103.

[0077] Step 3), placing the second wafer 104 above the first wafer 103 in the wafer bonding equipment, and based on the photosensitive ranging device 101, determining the distance distribution between the top surface of the second wafer 104 and the photosensitive ranging device 101 by receiving and feeding back optical signals, thereby obtaining the second warpage distribution value of the second wafer 104.

[0078] Step 4), according to the first warpage distribution value and the second warpage distribution value of the second wafer 104, the deformation amount that needs to be changed in each area of ​​the first wafer 103 is obtained; the adsorption device 102 applies adsorption force from the bottom of the first wafer 103 to the first wafer 103 according to the adsorption value that needs to be compensated for the first wafer 103, so as to quantitatively compensate for the deformation amount of the first wafer 103, so that the bonding surfaces of the first wafer 103 and the second wafer 104 remain relatively parallel.

[0079] Step 5), the wafer bonding equipment calculates the value that needs to be compensated for this wafer based on the accuracy measurement result of the previous bonded wafer through the internal program of the bonding machine, and then calculates the gas volume and rate that needs to be applied to each hole.

[0080] Step 6), the blowing pin 20 moves slowly downward, and stops when it is 2-3 mm away from the first wafer, and then applies a downward pressure to the first wafer 103 through the blowing hole 201. The gas volume can be adjusted according to the thickness of the product and the size of the chip, and the force application time is maintained for 3-5 seconds.

[0081] Step 7), the blowing process is completed, the center area of ​​the wafer is bonded, and then other areas are quickly bonded together due to hydrogen bonding, and finally the entire wafer is pre-bonded.

[0082] Step 8), the pre-bonded wafer stack is sent to the alignment measurement module through a conveyor to measure the bonding accuracy, and the result is fed back to the wafer bonding equipment.

[0083] Step 9) After the bonding accuracy measurement is completed, the wafer stack is then sent out of the wafer bonding equipment by the conveyor, and the operation is completed.

[0084] As described above, the wafer bonding device of the present invention has the following beneficial effects:

[0085] During the operation of the bonding machine, the present invention changes the force-bearing ejector pin into a multi-hole blowing ejector pin, so that the bonding process changes from hard contact to soft contact, and overcomes the problem of deformation of the wafer due to force. The present invention adopts a multi-hole blowing mode and an internal feedback measurement mechanism of the machine, which can effectively compensate for the accuracy and rotation deviation of the middle area of ​​the wafer, and finally achieve the effect of improving the bonding quality. The present invention can completely solve the deformation problem of the wafer caused by force during the bonding process, improve the bonding accuracy and bonding quality, and realize the metal interconnection technology between wafers in the true sense. The present invention can be well compatible with the currently used hybrid bonding machine and has good practical application value.

[0086] According to the warpage distribution of the upper and lower wafers, the present invention connects corresponding vacuum adsorption holes to different areas of the lower chuck, and mechanically changes the warpage condition of the bottom wafer by controlling the adsorption values ​​of the adsorption holes in different areas, so that the upper and lower wafers are in a relatively parallel state, so that during the wafer force bonding process, bubbles and alignment accuracy errors are greatly reduced, thereby improving the bonding process quality.

[0087] The present invention installs a photosensitive distance measuring device inside the bonding machine, and connects different adsorption holes in different areas of the lower chuck. The warpage distribution of the wafer is calculated by simulating the inside of the machine, and the adsorption value is changed accordingly during the bonding process. The present invention has good compatibility with the bonding machine, can also be widely used in multi-layer bonding, and has good practical application value.

[0088] The use of the equipment and method of the present invention can completely solve the problems of wafer warping and wafer deformation during bonding, and can effectively reduce production costs and process complexity.

[0089] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0090] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A wafer bonding device, characterized in that: The wafer bonding equipment comprises: An adsorption device is disposed below the first wafer and the second wafer, wherein the second wafer is located above the first wafer; an air blowing ejector pin, arranged above the second wafer, for blowing air toward the middle area of ​​the second wafer at a position not contacting the second wafer, so that the first wafer and the second wafer are bonded under the pressure generated by the air blowing; a photosensitive distance measuring device, arranged above the first wafer and the second wafer, for determining the distance distribution between the first wafer and the photosensitive distance measuring device, and determining the distance distribution between the second wafer and the photosensitive distance measuring device through receiving and feeding back optical signals, so as to obtain a first warpage distribution value of the first wafer and a second warpage distribution value of the second wafer; the photosensitive distance measuring device is also used to obtain the deformation amount required to be changed in each area of ​​the first wafer according to the first warpage distribution value and the second warpage distribution value; The adsorption device comprises a plurality of adsorption units, and the adsorption device controls the adsorption force of the corresponding area based on the deformation amount that needs to be changed in each area of ​​the first wafer; the adsorption device applies adsorption forces of different strengths from the bottom of the first wafer to the first wafer sub-areas according to the adsorption value that needs to be compensated for the first wafer, so as to quantitatively compensate the deformation amount of the first wafer, so that the bonding surfaces of the first wafer and the second wafer remain relatively parallel; The blowing ejector pin includes a plurality of blowing holes, and the pressure generated by each blowing hole is independently adjustable. The pressure generated by each blowing hole is adjusted according to the alignment data of the first wafer and the second wafer to reduce the deformation and extension of the middle area of ​​the second wafer.

2. The wafer bonding device according to claim 1, characterized in that: It also includes an alignment measurement module for obtaining the alignment data of the first wafer and the second wafer, wherein the alignment data includes the deformation amount and extension amount data of the force-bearing area after wafer bonding, and the alignment data is stored and fed back to the wafer bonding equipment.

3. The wafer bonding device according to claim 1, characterized in that: The blowing ejector pin is provided with a vertical motion device, and when the blowing ejector pin blows air over the middle area of ​​the second wafer, the distance between the blowing ejector pin and the second wafer is 2-3 mm.

4. The wafer bonding device according to claim 1, characterized in that: The adsorption force is obtained by the following formula: F = k△x + B; Wherein, F is the adsorption force, k is the elastic constant of the first wafer, and B is a fixed constant.

5. The wafer bonding device according to claim 1, characterized in that: The adsorption device includes a vacuum suction cup, and a plurality of adsorption holes are provided on the surface of the vacuum suction cup. The adsorption force of the adsorption holes is adjusted by setting the vacuum degree of the vacuum suction cup and the aperture of the adsorption holes, wherein the magnitude of the adsorption force is positively correlated with the vacuum degree and negatively correlated with the aperture of the adsorption holes.

6. The wafer bonding device according to claim 5, characterized in that: The vacuum suction cup includes a plurality of vacuum cavities, each of which is correspondingly provided with one or more adsorption holes, and the vacuum degree in each vacuum cavity is independently adjustable to control the adsorption force of the corresponding area.

7. The wafer bonding equipment according to claim 5 or 6, characterized in that: The shape of the adsorption hole includes one of a circular hole, an arc hole and a ring hole.

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