CN114613693A - Wafer bonding equipment - Google Patents

Wafer bonding equipment Download PDF

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Publication number
CN114613693A
CN114613693A CN202011445273.9A CN202011445273A CN114613693A CN 114613693 A CN114613693 A CN 114613693A CN 202011445273 A CN202011445273 A CN 202011445273A CN 114613693 A CN114613693 A CN 114613693A
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China
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wafer
adsorption
bonding
air blowing
bonding apparatus
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CN202011445273.9A
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Chinese (zh)
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霍进迁
龚燕飞
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Shanghai Industrial Utechnology Research Institute
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Shanghai Industrial Utechnology Research Institute
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Priority to CN202011445273.9A priority Critical patent/CN114613693A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67121—Apparatus for making assemblies not otherwise provided for, e.g. package constructions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/185—Joining of semiconductor bodies for junction formation
    • H01L21/187—Joining of semiconductor bodies for junction formation by direct bonding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67288—Monitoring of warpage, curvature, damage, defects or the like
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6838—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping with gripping and holding devices using a vacuum; Bernoulli devices

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)

Abstract

The present invention provides a wafer bonding apparatus, comprising: the adsorption device is arranged below the first wafer and the second wafer, and the second wafer is positioned above the first wafer; and the air blowing thimble is arranged above the second wafer and used for blowing air towards the middle area of the second wafer at a position not contacting the second wafer so as to bond the first wafer and the second wafer under the pressure generated by the air blowing. The invention can completely solve the problem of deformation of the wafers caused by stress in the bonding process, improve the bonding precision and the bonding quality and realize the metal interconnection technology between the wafers in the real sense. The invention can be well compatible with the existing mixed bonding machine, and has good practical application value.

Description

Wafer bonding equipment
Technical Field
The invention belongs to the field of semiconductor equipment design, and particularly relates to wafer bonding equipment.
Background
The wafer bonding technology is that two mirror polished homogeneous or heterogeneous wafers are tightly combined through chemical and physical actions, and after the wafers are combined, atoms on an interface are acted by external force to react to form covalent bonds to be combined into a whole, so that the combined interface achieves specific bonding strength.
In the field of MEMS and IC manufacturing, a bonding process plays an important role, and the traditional silicon-silicon bonding adopts pattern recognition, and the lens alignment mode enables the positions of an upper silicon wafer and a lower silicon wafer to coincide, so that direct bonding is carried out. In the actual process operation of the model, due to factors such as the warping of the silicon wafer, gas is not easy to be discharged from the interior of the silicon wafer in the bonding process and can affect the alignment precision, typically, bubbles are increased or the alignment precision is poor, the yield of products is affected, and the products are even scrapped under extreme conditions.
The conventional solution is to control the quality of the silicon wafer material before the process, and to require the warpage of the silicon wafer to be kept within a certain range before bonding. However, an obvious clamping control is invisibly defined for other processes, so that a plurality of structures cannot be constructed, and the production process cost of the product is greatly increased.
In the field of MEMS and IC manufacturing, multi-chip stacking is proposed as a solution in the industry in order to meet the growing demand and overcome the limitations of moore's law. With the application of advanced packaging technology, the 2.5D stack adopts the development and application of through silicon via technology. Nowadays, the expansion of wafers in the vertical direction is becoming more and more important in so-called 3D stacking, while hybrid bonding techniques between silicon wafers are considered as the best solution for achieving permanent bonding.
In actual process operation, a high-precision alignment system is adopted by a current hybrid bonding machine to align the upper wafer and the lower wafer in a reference mode, then an external pressure is applied to the upper wafer through one top of the machine to enable the two wafers to be in contact from the center, then the two wafers rapidly spread to the periphery through hydrogen bonds, and the two wafers in the group are subjected to high-precision pre-bonding.
However, the process has an obvious disadvantage that the appearance of the upper wafer is changed by the externally applied pressure, and particularly, the stress point generates deformation which is difficult to recover, so that the wafer which is pre-bonded at the later stage generates slight clearance and the alignment precision is influenced. Such deformation is more pronounced for substrates with thin thicknesses.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention is directed to a wafer bonding apparatus, which is used to solve the problem of deformation generated during the pre-bonding stress process of the semiconductor wafer in the prior art and how to reduce the deformation and improve the bonding precision.
To achieve the above and other related objects, the present invention provides a wafer bonding apparatus, comprising: the adsorption device is arranged below the first wafer and the second wafer, and the second wafer is positioned above the first wafer; and the air blowing thimble is arranged above the second wafer and used for blowing air towards the middle area of the second wafer at a position not contacting the second wafer so as to bond the first wafer and the second wafer under the pressure generated by air blowing.
Optionally, the air blowing thimble comprises a plurality of air blowing holes, pressure generated by each air blowing hole is independently adjustable, and the pressure generated by each air blowing hole is adjusted through alignment data of the first wafer and the second wafer so as to reduce deformation and extension of the middle area of the second wafer.
Optionally, the wafer bonding apparatus further includes an alignment measurement module, configured to acquire alignment data of the first wafer and the second wafer, where the alignment data includes deformation and extension data of a stressed area after wafer bonding, and store and feed back the alignment data to the wafer bonding apparatus.
Optionally, the air blowing thimble is provided with a vertical movement device, and when the air blowing thimble blows air beyond the middle area of the second wafer, the distance between the air blowing thimble and the second wafer is 2-3 mm.
Optionally, the wafer bonding apparatus further includes: the photosensitive ranging device is arranged above the first wafer and the second wafer and used for determining the distance distribution between the first wafer and the photosensitive ranging device and the distance distribution between the second wafer and the photosensitive ranging device through 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; the adsorption device is arranged below the first wafer and comprises a plurality of adsorption units, the adsorption unit is used for quantitatively compensating the deformation of the first wafer, and the adsorption device gives adsorption force to the first wafer from the bottom of the first wafer according to the adsorption value of the first wafer to be compensated so as to quantitatively compensate the deformation of the first wafer and enable the bonding surfaces of the first wafer and the second wafer to be kept relatively parallel.
Optionally, the photosensitive ranging device is further configured to obtain a deformation amount that needs to be changed in each area of the first wafer according to the first warpage distribution value and the second warpage distribution value of the second wafer; and the adsorption device controls the adsorption force of the corresponding area based on the deformation quantity needing to be changed so as to quantitatively compensate the deformation quantity of the first wafer and ensure that the bonding surfaces of the first wafer and the second wafer are kept relatively parallel.
Optionally, the adsorption force is obtained by the following formula:
F＝k△x+B；
wherein F is the absorption force, k is the elastic constant of the second wafer, and B is the fixed constant.
Optionally, adsorption equipment includes vacuum chuck, the vacuum chuck surface has a plurality of adsorption holes, through setting up vacuum chuck's vacuum and the aperture of adsorption hole are in order to adjust the adsorption affinity of adsorption hole, wherein, the size of adsorption affinity with vacuum is positive correlation, with the aperture of adsorption hole is negative correlation.
Optionally, the vacuum chuck 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 region.
Optionally, the shape of the adsorption hole includes one of a circular hole, an arc-shaped hole, and an annular hole.
As described above, the wafer bonding apparatus of the present invention has the following advantages:
in the invention, in the operation process of the bonding machine, the stressed thimble is changed into the air blowing thimble with a plurality of air holes, so that the bonding process is changed from hard contact to soft contact, and the problem of deformation of the wafer caused by stress is solved. The invention can completely solve the problem of deformation of the wafers caused by stress in the bonding process, improve the bonding precision and the bonding quality and realize the metal interconnection technology between the wafers in the real sense. The invention can be well compatible with the existing hybrid bonding machine, and has good practical application value.
According to the invention, corresponding vacuum adsorption holes are accessed to different areas of the lower chuck according to the warpage distribution of the upper and lower wafers, and the warpage condition of the bottom wafer is mechanically changed by controlling the adsorption values of the adsorption holes in the different areas, so that the upper and lower wafers are in a relatively parallel state, bubbles and alignment precision errors are greatly reduced in the stressed bonding process of the wafers, and the bonding process quality is improved.
According to the invention, the photosensitive ranging device is arranged in the bonding machine table, the lower chuck is connected with different adsorption holes in different areas, the warping distribution of the wafer is simulated and calculated through the interior of the machine table, the adsorption value is correspondingly changed in the bonding process, and the bonding machine table has good compatibility with the bonding machine table, can also be widely applied to multilayer bonding, and has good practical application value.
The equipment and the method can completely solve the problems of wafer warping in the bonding process and wafer deformation in the bonding process, and can effectively reduce the production cost and the process complexity.
Drawings
Fig. 1 is a schematic structural diagram of a wafer bonding apparatus according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of an adsorption device of a wafer bonding apparatus according to an embodiment of the present invention.
Fig. 3 is a schematic diagram illustrating a wafer warpage distribution value obtained by the wafer bonding apparatus according to an embodiment of the present invention.
Fig. 4 is a schematic diagram illustrating a principle of the quantitative compensation deformation amount of the wafer bonding apparatus according to the embodiment of the invention.
Fig. 5 is a schematic view showing a distribution structure of blowing holes of a blowing thimble of the wafer bonding apparatus according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of data of deformation and expansion of a wafer after bonding according to an embodiment of the present invention.
Fig. 7 is a schematic diagram illustrating compensation performed by the wafer bonding apparatus according to the data of the wafer, and effective reduction of deformation and extension of the wafer in the central stressed area by adjusting the alignment data and the gas amount of different gases in the gas blowing holes according to the embodiment of the present invention.
Fig. 8 is a schematic diagram illustrating that the blowing thimble of the wafer bonding apparatus according to the embodiment of the present invention can effectively make the wafer uniformly stressed, so that the wafer is deformed at regular rate.
FIG. 9 is a schematic diagram of a conventional tool applying an external pressure to an upper wafer by jacking the tool, the external pressure changing the topography of the upper wafer.
Description of the element reference numerals
101 photosensitive ranging device
102 adsorption device
103 first wafer
104 second wafer
105 first wafer after quantitative compensation of deformation quantity
106 adsorption holes
1061 round hole
1062 annular hole
1063 arc hole
20 air blowing thimble
201 air blowing hole
30 thimble
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.
For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, 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.
In the context of this application, a structure described as having a first feature "on" 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 in between the first and second features, such that the first and second features may not be in direct contact.
It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.
The mode of reducing warpage of the traditional bonding machine is generally to change the warpage value of the wafer by using ultra-high pressure, but the mode can cause the wafer to deform under pressure, thereby affecting the bonding precision. The invention aims to install a photosensitive ranging device 101 in a bonding machine, simulate the warping and distribution of a wafer in the bonding process and then feed back to the bonding machine. The bonding machine gives different adsorption strengths to the bottom layer wafer in different areas in the stress process of the bonding according to the warpage distribution of the upper and lower layers of wafers, quantitatively changes the warpage value of the bottom layer wafer to be close to the warpage distribution of the top layer wafer, and finally enables the two wafers to keep opposite parallel distribution.
Further, in the current mixed wafer direct bonding technology, the precision is as high as 50nm, so that a small deformation of the wafer can affect the bonding effect. Conventionally, an external pressure is applied to an upper wafer through a thimble 30 of a machine, as shown in fig. 9, two wafers are brought into contact from the center and then rapidly spread to the periphery through hydrogen bonds, and the two wafers in a group are subjected to high-precision pre-bonding. However, the process has an obvious disadvantage that the appearance of the upper wafer is changed by the externally applied pressure, and particularly, the stress point generates deformation which is difficult to recover, so that the wafer which is pre-bonded at the later stage generates slight clearance and the alignment precision is influenced. Such deformation is more pronounced for substrates with thin thicknesses.
The invention calculates the deformation of the bottom wafer by measuring the warpage distribution of the two wafers. For wafers with the same process, the strain in the vertical direction approximately meets the linear relation, the strain is correspondingly written into a production program of a bonding machine, and the targeted compensation can be performed on different warps of the supplied wafers, so that the wafers are kept in a horizontal state all the time in the bonding process, and the bonding process quality is improved. Then, after the alignment system of the bonding machine completes pre-alignment, the wafer is subjected to external force for pre-bonding, at the moment, the external force which is directly contacted with the wafer by the outside is only required to be applied to the wafer and changed into air flow controlled by a pneumatic valve, the deformation of the wafer is reduced through a blowing force application model, and then the precision problem in the bonding force application process is solved. And because the force application process is carried out in the normal temperature and normal pressure environment, the adoption of the blowing force application model can not generate negative influence on the bonding process.
As shown in fig. 1 and 8, the present embodiment provides a wafer bonding apparatus, including: photosensitive range finder 10, adsorption equipment 102 and the thimble of blowing.
The adsorption device 102 is disposed below a first wafer 103 and a second wafer 104, and the second wafer 104 is located above the first wafer 103.
As shown in fig. 8, a blowing thimble 20 is disposed above the second wafer 104 for blowing air toward a middle region of the second wafer 104 at a position not contacting the second wafer 104, so that the first wafer 103 and the second wafer 104 are bonded under a pressure generated by the blowing air.
As shown in fig. 5, the air blowing thimble 20 includes a plurality of air blowing holes 201, and the pressure generated by each air blowing hole 201 is independently adjustable, and the pressure generated by each air blowing hole 201 is adjusted according to the alignment data of the first wafer 103 and the second wafer 104, so as to reduce the deformation and extension of the middle region of the second wafer 104. The air blowing thimble 20 is provided with a vertical movement device, and when the air blowing thimble blows air beyond the middle area of the second wafer 104, the distance between the air blowing thimble 20 and the second wafer 104 is 2-3 mm.
The invention applies pressure by adopting a mode of blowing by the small blowing holes instead of local hard contact of the existing force application thimble, thereby avoiding overlarge deformation of a stress point area caused by the local hard force received by the upper layer wafer. The gas of the blowing thimble can adopt nitrogen, the blowing thimble can follow a square shape of 2cm multiplied by 2cm or a circular force application area with a diameter of about 2cm (the area is consistent with the force application area of the traditional force application thimble), the blowing small holes are 2mm multiplied by 2mm (about 50 air holes), and the air quantity of the blowing small holes can be independently set, so that the wafer can be uniformly stressed by adopting a blowing mode, and the regular deformation occurs, as shown in fig. 8, the orderly bonding of the upper wafer and the lower wafer in the bonding process is ensured.
The wafer bonding apparatus further includes an alignment measurement module, configured to acquire alignment data of the first wafer 103 and the second wafer 104, where the alignment data includes deformation amount and extension amount data of a stressed area after wafer bonding, as shown in fig. 6, and store and feed back the alignment data to the wafer bonding apparatus.
In addition, after the wafer is bonded, the wafer is transferred to an alignment metrology module, and the deformation and extension data of the stress area of the bonded wafer is measured, as shown in fig. 6, and then may be transmitted back to the alignment and blowing system based on the data. According to the rule that the states of the same batch of wafers are approximately consistent, the wafer bonding equipment can compensate according to the data of the wafers, and by adjusting the alignment data and the gas amounts of different gases of the gas blowing holes 201, as shown in fig. 7, the deformation and extension of the wafers in the central stressed area are effectively reduced, the alignment precision and the electrical contact under the mixed bonding mode are ensured, and the metal interconnection under the real meaning is realized.
The photosensitive ranging device 101 is disposed above the first wafer 103 and the second wafer 104, and configured to determine, through receiving and feedback of optical signals, a distance distribution between a top surface of the first wafer 103 and the photosensitive ranging device 101, and a distance distribution between a top surface of the second wafer 104 and the photosensitive ranging device 101, so as to obtain a first warpage distribution value of the first wafer 103 and a second warpage distribution value of the second wafer 104, where the second wafer 104 is located above the first wafer 103.
For example, the photosensitive ranging device 101 includes a photosensitive ranging chuck, which emits light to the wafer and then reflects the light to the wafer, when the wafer is warped, the reflected light signals at different positions have differences, and the photosensitive ranging chuck determines the distance distribution between the top surface of the wafer and the photosensitive ranging chuck according to the differences, so as to obtain the warp distribution value of the wafer, as shown in fig. 3.
In the application process, the photosensitive ranging chuck is fixed above the inside of the wafer bonding equipment through a detachable connecting piece such as a screw, the photosensitive ranging chuck can be connected with a power supply line of the wafer bonding equipment for power supply, and can also be supplied with power through a battery carried by the photosensitive ranging chuck, and the photosensitive ranging chuck can be connected with the adsorption device 102 in a wired or wireless mode so as to realize signal connection between the photosensitive ranging chuck and the adsorption device 102.
Further, in this embodiment, the photosensitive ranging device 101 is further configured to obtain deformation amounts, which need to be changed, of 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.
As shown in fig. 1 to 4, the adsorption device 102 is disposed below the first wafer 103, the adsorption device 102 includes a plurality of adsorption units, and the adsorption device 102 provides an adsorption force to the first wafer 103 from the bottom of the first wafer 103 according to an adsorption value of the first wafer 103 to be compensated, so as to quantitatively compensate a deformation amount of the first wafer 103, obtain a second wafer 105 with the deformation amount compensated quantitatively, and keep bonding surfaces of the first wafer 103 and the second wafer 104 relatively parallel.
In this embodiment, the suction device 102 controls the suction force of the corresponding region based on the deformation amount required to be changed fed back by the photosensitive ranging device 101, so as to quantitatively compensate the deformation amount of the first wafer 103, and keep the bonding surfaces of the first wafer 103 and the second wafer 104 relatively parallel.
In the present embodiment, the adsorption force is obtained by the following formula: f ═ k Δ x + B; where F is the absorption force, k is the elastic constant of the first wafer 103, and B is the fixed constant. For the wafers with the same process, the strain in the vertical direction approximately meets the linear relation, the strain is correspondingly written into a production program of bonding equipment, and the targeted compensation can be performed on different warps of the supplied wafers, so that the wafers are kept in a horizontal state all the time in the bonding process, and the bonding process quality is improved.
As shown in fig. 1 and 2, the suction device 102 includes a vacuum chuck having a plurality of suction holes 106 on a surface thereof, and adjusts a suction force of the suction holes 106 by setting a vacuum degree of the vacuum chuck and a hole diameter of the suction holes 106, wherein the magnitude of the suction force is positively related to the vacuum degree and negatively related to the hole diameter of the suction holes 106.
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 vacuum chamber includes one or more suction holes 106, and the vacuum degree in each vacuum chamber is independently adjustable to control the suction force of the corresponding area. According to the method, different adsorption strengths are given to the bottom layer wafer in different areas, the warping value of the bottom layer wafer is quantitatively changed to be close to the warping distribution of the top layer wafer, and finally the two wafers are kept in relative parallel distribution.
As wafer warpage is generally serious in wafer edge warpage, and warpage in the central area is small, in a specific implementation process, the density of the adsorption holes 106 of the adsorption device 102 corresponding to the edge area of the first wafer 103 is greater than the density of the adsorption holes 106 located in the central area of the first wafer 103, and the aperture of the adsorption holes 106 of the adsorption device 102 corresponding to the edge area of the first wafer 103 is smaller than the aperture of the adsorption holes 106 located in the central area of the first wafer 103.
The shape of the suction hole 106 includes one of a circular hole 1061, an arc hole 1063 and an annular hole 1062, as shown in fig. 2, but the shape of the suction hole 106 may also be rectangular, triangular, diamond-shaped, oval, etc., and is not limited to the examples listed herein. In this embodiment, the adsorption hole 106 inside the adsorption device 102 is a circular hole 1061, the adsorption hole 106 in the middle of the adsorption device 102 is an annular hole 1062, and the adsorption hole 106 at the edge of the adsorption device 102 is an arc hole 1063, further, 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 respective independent vacuum chambers, so that the adsorption force of the adsorption hole 106 in each region is independently adjustable, the configuration is more widely applicable to improving wafer warpage, and can be used for deformation compensation of most wafer warpage, so that in most cases, deformation compensation of wafer warpage can be realized without replacing the adsorption device 102, and cost can be effectively saved.
As shown in fig. 1 to fig. 4, the present embodiment further provides a wafer bonding method for eliminating wafer warpage, including:
step 1), providing the wafer bonding equipment as described in any one of the above items;
step 2), placing the first wafer 103 in the wafer bonding equipment, and determining the distance distribution between the top surface of the first wafer 103 and the photosensitive ranging device 101 through the receiving and feedback of optical signals based on the photosensitive ranging device 101, so as to obtain a first warpage distribution value of the first wafer 103.
And 3), placing a second wafer 104 above the first wafer 103 in the wafer bonding equipment, and determining the distance distribution between the top surface of the second wafer 104 and the photosensitive ranging device 101 through receiving and feeding back optical signals based on the photosensitive ranging device 101, so as to obtain a second warpage distribution value of the second wafer 104.
Step 4), acquiring deformation quantity required to be changed in each area of the first wafer 103 according to the first warpage distribution value and the second warpage distribution value of the second wafer 104; the adsorption device 102 gives an adsorption force to the first wafer 103 from the bottom of the first wafer 103 according to an adsorption value of the first wafer 103 to be compensated, so as to quantitatively compensate the deformation of the first wafer 103, and keep the bonding surfaces of the first wafer 103 and the second wafer 104 relatively parallel.
And 5) calculating the value of the wafer to be compensated by the wafer bonding equipment according to the precision measurement result of the last bonding piece by using an internal program of the bonding machine table, and further obtaining the gas quantity and the gas speed required to be applied to each gas hole.
And 6), slowly moving the air blowing thimble 20 downwards, stopping moving when the distance is 2-3mm from the first wafer, applying downward pressure to the first wafer 103 through the air blowing hole 201, wherein the air quantity of the air can be correspondingly adjusted according to the thickness of a product and the size of a chip, and the force application time is maintained for 3-5 seconds.
And 7), finishing the blowing process, finishing bonding in the central area of the wafer, then quickly bonding other areas together due to hydrogen bonds, and finally finishing pre-bonding of the whole wafer.
And 8), conveying the wafer lamination after pre-bonding to an alignment measurement module through a conveying device, measuring the bonding precision, and feeding the result back to the wafer bonding equipment.
And 9), finishing the measurement of the bonding precision, and sending the wafer lamination out of the wafer bonding equipment by the transmission device, thus finishing the operation.
As described above, the wafer bonding apparatus of the present invention has the following advantages:
in the invention, in the operation process of the bonding machine, the stressed thimble is changed into the air blowing thimble with a plurality of air holes, so that the bonding process is changed from hard contact to soft contact, and the problem of deformation of the wafer caused by stress is solved. The invention can completely solve the problem of deformation of the wafers caused by stress in the bonding process, improve the bonding precision and the bonding quality and realize the metal interconnection technology between the wafers in the real sense. The invention can be well compatible with the existing hybrid bonding machine, and has good practical application value.
According to the invention, corresponding vacuum adsorption holes are accessed to different areas of the lower chuck according to the warpage distribution of the upper and lower wafers, and the warpage condition of the bottom wafer is mechanically changed by controlling the adsorption values of the adsorption holes in the different areas, so that the upper and lower wafers are in a relatively parallel state, bubbles and alignment precision errors are greatly reduced in the stressed bonding process of the wafers, and the bonding process quality is improved.
According to the invention, the photosensitive ranging device is arranged in the bonding machine table, the lower chuck is connected with different adsorption holes in different areas, the warping distribution of the wafer is simulated and calculated through the interior of the machine table, the adsorption value is correspondingly changed in the bonding process, and the bonding machine table has good compatibility with the bonding machine table, can also be widely applied to multilayer bonding, and has good practical application value.
The equipment and the method can completely solve the problems of wafer warping in the bonding process and wafer deformation in the bonding process, and can effectively reduce the production cost and the process complexity.
Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (10)

1. A wafer bonding apparatus, comprising:
the adsorption device is arranged below the first wafer and the second wafer, and the second wafer is positioned above the first wafer;
and the air blowing thimble is arranged above the second wafer and used for blowing air towards the middle area of the second wafer at a position not contacting the second wafer so as to bond the first wafer and the second wafer under the pressure generated by air blowing.
2. The wafer bonding apparatus of claim 1, wherein: the air blowing thimble comprises a plurality of air blowing holes, the pressure generated by each air blowing hole is independently adjustable, and the pressure generated by each air blowing hole is adjusted through the alignment data of the first wafer and the second wafer so as to reduce the deformation and extension of the middle area of the second wafer.
3. The wafer bonding apparatus of claim 2, wherein: the alignment measurement module is used for acquiring alignment data of the first wafer and the second wafer, wherein the alignment data comprises deformation quantity and extension quantity data of a stress area after wafer bonding, and the alignment data is stored and fed back to the wafer bonding equipment.
4. The wafer bonding apparatus of claim 1, wherein: the air blowing thimble is provided with a vertical movement device, and when the air blowing thimble blows air beyond the middle area of the second wafer, the distance between the air blowing thimble and the second wafer is 2-3 mm.
5. The wafer bonding apparatus of claim 1, wherein: the wafer bonding apparatus further comprises:
the photosensitive ranging device is arranged above the first wafer and the second wafer and used for determining the distance distribution between the first wafer and the photosensitive ranging device and the distance distribution between the second wafer and the photosensitive ranging device through 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;
the adsorption device is arranged below the first wafer and comprises a plurality of adsorption units, the adsorption unit is used for quantitatively compensating the deformation of the first wafer, and the adsorption device gives adsorption force to the first wafer from the bottom of the first wafer according to the adsorption value of the first wafer to be compensated so as to quantitatively compensate the deformation of the first wafer and enable the bonding surfaces of the first wafer and the second wafer to be kept relatively parallel.
6. The wafer bonding apparatus of claim 5, wherein:
the photosensitive ranging device is further used for acquiring deformation quantity of each area of the first wafer, which needs to be changed, according to the first warping distribution value and the second warping distribution value of the second wafer;
and the adsorption device controls the adsorption force of the corresponding area based on the deformation quantity needing to be changed so as to quantitatively compensate the deformation quantity of the first wafer and ensure that the bonding surfaces of the first wafer and the second wafer are kept relatively parallel.
7. The wafer bonding apparatus of claim 6, wherein: the adsorption force is obtained by the following formula:
F＝k△x+B；
wherein F is the absorption force, k is the elastic constant of the second wafer, and B is the fixed constant.
8. The wafer bonding apparatus of claim 5, wherein: adsorption equipment includes vacuum chuck, vacuum chuck surface has a plurality of adsorption holes, through setting vacuum chuck's vacuum and the aperture in adsorption holes are in order to adjust the adsorption affinity in adsorption holes, wherein, the size of adsorption affinity with vacuum is positive correlation, with the aperture in adsorption holes is negative correlation.
9. The wafer bonding apparatus of claim 5, wherein: the vacuum chuck comprises 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 so as to control the adsorption force of the corresponding area.
10. Wafer bonding apparatus as claimed in claim 8 or 9, characterized in that: the shape of the adsorption hole comprises one of a round hole, an arc-shaped hole and an annular hole.
CN202011445273.9A 2020-12-08 2020-12-08 Wafer bonding equipment Pending CN114613693A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100809275B1 (en) * 2006-11-13 2008-03-03 앰코 테크놀로지 코리아 주식회사 Alignment zone for wafer mount machine
CN109451761A (en) * 2018-05-17 2019-03-08 长江存储科技有限责任公司 For adjusting the method and system of wafer distortion during wafer bonding
CN109585346A (en) * 2019-01-02 2019-04-05 长江存储科技有限责任公司 Wafer bonding device and wafer bonding method
CN109887860A (en) * 2018-12-28 2019-06-14 上海集成电路研发中心有限公司 A kind of bonding cavity body structure and bonding method
CN214313133U (en) * 2020-12-08 2021-09-28 上海新微技术研发中心有限公司 Wafer bonding equipment

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100809275B1 (en) * 2006-11-13 2008-03-03 앰코 테크놀로지 코리아 주식회사 Alignment zone for wafer mount machine
CN109451761A (en) * 2018-05-17 2019-03-08 长江存储科技有限责任公司 For adjusting the method and system of wafer distortion during wafer bonding
CN109887860A (en) * 2018-12-28 2019-06-14 上海集成电路研发中心有限公司 A kind of bonding cavity body structure and bonding method
CN109585346A (en) * 2019-01-02 2019-04-05 长江存储科技有限责任公司 Wafer bonding device and wafer bonding method
CN214313133U (en) * 2020-12-08 2021-09-28 上海新微技术研发中心有限公司 Wafer bonding equipment

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