Method of manufacturing a semiconductor structure

Abstract

The application provides a preparation method of a semiconductor structure. The preparation method comprises the following steps: forming a first electrode on a first surface of a first substrate; forming a first structure layer comprising a first main layer and a first protruding column on one side of the first main layer; bonding the first substrate and the first structure layer; processing the first main layer to form a patterned second main layer and a second protruding column, wherein the second main layer comprises a mass structure, and a normal projection of the mass structure on the first surface at least partially overlaps with a normal projection of the first electrode on the first surface; forming a second electrode on a second surface of a second substrate, and a difference between a height of the second protruding column and a thickness of the second electrode is equal to a difference between a height of the first protruding column and a thickness of the first electrode; and bonding the second substrate and a second structure layer, so that the second protruding column is in contact with the second surface, the height of the second protruding column remains unchanged, and a normal projection of the second electrode on the first surface coincides with a normal projection of the first electrode on the first surface.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for fabricating a semiconductor structure. Background Technology

[0002] MEMS (Micro-Electro-Mechanical Systems) chips are semiconductor devices that integrate micromechanical structures and microelectronic circuits. They can improve their ability to detect minute signals by setting up double-sided electrodes.

[0003] Existing MEMS chips cannot guarantee the capacitance symmetry of double-sided electrodes during vacuum packaging, which negatively impacts the measurement performance and reliability of MEMS chips. Summary of the Invention

[0004] This application provides a method for fabricating a semiconductor structure. The fabrication method includes:

[0005] A first electrode is formed on a first surface of a first substrate;

[0006] A first structural layer is formed; the first structural layer includes a first main body layer and a first protruding pillar located on one side of the first main body layer;

[0007] The first substrate is bonded to the first structural layer, so that the first protrusion contacts the first surface, and the height of the first protrusion remains unchanged;

[0008] The first main body layer is processed to form a patterned second main body layer and a second protrusion located on the side of the second main body layer away from the first protrusion, resulting in a second structural layer including the second main body layer, the second protrusion, and the first protrusion; the second main body layer includes a mass structure; the orthographic projection of the mass structure on the first surface at least partially overlaps with the orthographic projection of the first electrode on the first surface;

[0009] A second electrode is formed on the second surface of the second substrate; the difference between the height of the second protrusion and the thickness of the second electrode is equal to the difference between the height of the first protrusion and the thickness of the first electrode.

[0010] The second substrate is bonded to the second structural layer, so that the second protrusion contacts the second surface, and the height of the second protrusion remains unchanged; the orthographic projection of the second electrode on the first surface coincides with the orthographic projection of the first electrode on the first surface.

[0011] In one embodiment, bonding the first substrate to the first structural layer includes:

[0012] The first protrusion is bonded to the first substrate using an anodic bonding process.

[0013] In one embodiment, during the step of processing the first main body layer, a third protrusion is further formed on the side of the second main body layer away from the first protrusion, and the second structural layer includes the third protrusion; the height of the third protrusion is less than the height of the second protrusion.

[0014] Before bonding the second substrate to the second structural layer, the fabrication method further includes: forming a first bonding structure on the side of the third protrusion away from the first protrusion; forming a second bonding structure on one side of the second substrate, wherein the second bonding structure and the second electrode are located on the same side of the second surface;

[0015] The step of bonding the second substrate to the second structural layer includes: bonding the first bonding structure to the second bonding structure, thereby bonding the second substrate to the second structural layer.

[0016] In one embodiment, before bonding the second substrate to the second structural layer, the sum of the thickness of the first bonding structure, the thickness of the portion of the second bonding structure in contact with the second substrate, and the thickness of the third protrusion is greater than the thickness of the second protrusion; during the bonding process of the second substrate to the second structural layer, the first bonding structure and the second bonding structure melt, and their sum of thicknesses decreases, so that the second protrusion contacts the second surface.

[0017] In one embodiment, the second protrusion includes a first sub-protrusion and a second sub-protrusion located on the side of the first sub-protrusion away from the second main body layer; the first sub-protrusion and the third protrusion have the same height and are formed synchronously.

[0018] In one embodiment, processing the first main body layer includes:

[0019] The surface of the first main body layer away from the first protrusion is etched to obtain a third main body layer and a second sub-protrusion located on the side of the third main body layer away from the first protrusion.

[0020] The surface of the third main body layer facing the second sub-protrusion is etched to obtain the second main body layer and the first sub-protrusion and the third protrusion located between the second main body layer and the second sub-protrusion.

[0021] In one embodiment, before bonding the second substrate to the second structural layer, the fabrication method further includes: forming a first bonding structure on the surface of the two main layers away from the first protrusion, the first bonding structure being in direct contact with the second main layer; and forming a second bonding structure on one side of the second substrate, the second bonding structure being located on the same side of the second surface as the second electrode.

[0022] The step of bonding the second substrate to the second structural layer includes: bonding the first bonding structure to the second bonding structure, thereby bonding the second substrate to the second structural layer.

[0023] In one embodiment, before bonding the second substrate to the second structural layer, the method for fabricating the semiconductor structure further includes: forming a first conductive line on a second surface of the second substrate;

[0024] The material of the second structural layer is a semiconductor material; the second bonding structure covers a portion of the first wire; the second main body layer includes a connecting portion connected to the third protrusion, and the second structural layer also includes a fourth protrusion connected to the connecting portion; the fourth protrusion and the first protrusion are located on the same side of the second main body layer and are in contact with the first electrode.

[0025] In one embodiment, the material of the second structural layer is a semiconductor material; the second structural layer further includes a fifth protrusion located on the side of the second main layer away from the first protrusion, the fifth protrusion being annular and surrounding the second protrusion; before bonding the second substrate to the second structural layer, the fabrication method further includes:

[0026] A first wire and a second wire are formed on the second surface of the second substrate; the second wire is electrically connected to the second electrode.

[0027] An insulating layer is formed, which covers a portion of the first conductor and a portion of the second conductor;

[0028] A third bonding structure is formed on the surface of the fifth protrusion away from the first protrusion, and a fourth bonding structure is formed on the surface of the insulating layer away from the second substrate;

[0029] The step of bonding the second substrate to the second structural layer includes: bonding the third bonding structure to the fourth bonding structure; after the second substrate is bonded to the second structural layer, the first wire is electrically connected to the first electrode.

[0030] In one embodiment, the first structural layer further includes a sixth protrusion, which is located on the same side of the first main body layer as the first protrusion; the sixth protrusion is annular and surrounds the first protrusion.

[0031] The bonding of the first substrate to the first structural layer includes:

[0032] Anodizing bonding process is used to bond the first protrusion and the sixth protrusion to the first substrate, respectively.

[0033] The semiconductor structure fabrication method provided in this application embodiment can ensure that the distance between the surface of the mass structure facing the first electrode and the first electrode is equal to the distance between the surface of the mass structure facing the second electrode and the second electrode. This enables the capacitance formed between the mass structure and the first electrode to be equal to the capacitance formed between the second electrode, allowing the semiconductor structure to detect minute changes in the signal more accurately, which is beneficial to improving the sensitivity and accuracy of semiconductor structure detection.

[0034] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 A schematic flowchart illustrating a method for fabricating a semiconductor structure according to an embodiment of this application;

[0037] Figures 2 to 25 This is a schematic diagram of the semiconductor structure obtained during the fabrication process of an embodiment of this application. Detailed Implementation

[0038] The technical solutions in the embodiments (or "implementations") of this application will be clearly and completely described herein with reference to the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0039] If the embodiments of this application contain terms relating to directional indications or positional relationships (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movements between components in a specific posture (as shown in the attached figures); if the specific posture changes, the directional indications or positional relationships will also change accordingly. Furthermore, the terms "first" and "second" used in the embodiments of this application are only for descriptive convenience and should not be construed as indicating or implying relative importance.

[0040] The method for fabricating the semiconductor structure according to embodiments of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can complement or combine with each other.

[0041] This application provides a method for fabricating a semiconductor structure, such as... Figure 1 As shown, the method for fabricating a semiconductor structure includes:

[0042] Step S100: Form a first electrode on the first surface of the first substrate.

[0043] Step S200: Form a first structural layer, the first structural layer including a first main body layer and a first protruding post located on one side of the first main body layer.

[0044] Step S300: Bond the first substrate to the first structural layer so that the first protrusion contacts the first surface, and the height of the first protrusion remains unchanged.

[0045] Step S400: Process the first main body layer to form a patterned second main body layer and a second protrusion located on the side of the second main body layer away from the first protrusion, resulting in a second structural layer including the second main body layer, the second protrusion, and the first protrusion. The second main body layer includes a mass structure, the orthographic projection of the mass structure on the first surface at least partially overlapping the orthographic projection of the first electrode on the first surface.

[0046] Step S500: A second electrode is formed on the second surface of the second substrate, wherein the difference between the height of the second protrusion and the thickness of the second electrode is equal to the difference between the height of the first protrusion and the thickness of the first electrode.

[0047] Step S600: Bond the second substrate to the second structural layer, so that the second protrusion contacts the second surface, and the height of the second protrusion remains unchanged. The orthographic projection of the second electrode on the first surface coincides with the orthographic projection of the first electrode on the first surface.

[0048] The semiconductor structure fabrication method provided in this application embodiment ensures that the distance between the surface of the mass structure facing the first electrode and the first electrode is equal to the difference between the height of the first protrusion and the thickness of the first electrode. Furthermore, during the bonding process between the first substrate and the first structural layer, the first protrusion contacts the first surface while maintaining a constant height. Similarly, during the bonding process between the second substrate and the second structural layer, the second protrusion contacts the second surface while maintaining a constant height. This ensures that the distance between the surface of the mass structure facing the first electrode and the first electrode is equal to the difference between the height of the first protrusion and the thickness of the first electrode, and the distance between the surface of the mass structure facing the second electrode and the second electrode is equal to the difference between the height of the second protrusion and the thickness of the second electrode. In other words, the distance between the surface of the mass structure facing the first electrode and the first electrode is equal to the distance between the surface of the mass structure facing the second electrode and the second electrode. Since the orthographic projection of the second electrode on the first surface coincides with the orthographic projection of the first electrode on the first surface, the capacitance formed between the mass structure and the first electrode and the capacitance formed between the second electrode are equal. This allows the semiconductor structure to more accurately detect minute changes in the signal, thereby improving the sensitivity and accuracy of semiconductor structure detection.

[0049] In one embodiment, step S100 can yield the following result: Figure 2 The structure shown. (As illustrated) Figure 2 As shown, the number of first electrodes 20 formed on the surface 101 of the first substrate 10 is greater than one. Step S100 specifically includes: forming a metal electrode layer on the first surface 101, and etching the metal electrode layer to form the first electrodes 20 through a patterning process. In some embodiments, the first substrate 10 may be a glass substrate.

[0050] In one embodiment, step S200 can yield the following result: Figure 3 The structure shown. (As illustrated) Figure 3 As shown, a plurality of first protrusions 321 are provided on one side surface of the first main body layer 31. Step S200 specifically includes forming a main film layer, and etching one side of the main film layer through a patterning process to form the first protrusions 321, thereby obtaining the first structural layer 30. In this embodiment, the material of the first main body layer 31 and the first protrusions 321 can be silicon. The main film layer can be etched using deep silicon etching technology and inductively coupled plasma etching technology.

[0051] Furthermore, such as Figure 3 As shown, the first structural layer 30 further includes a fourth protrusion 322, which is located on the same side of the first main body layer 31 as the first protrusion 321. In some embodiments, the fourth protrusion 322 may be formed in the same process step as the first protrusion 321. The height of the fourth protrusion 322 may be the same as the height of the first protrusion 321.

[0052] Furthermore, such as Figure 3 As shown, the first structural layer 30 also includes a sixth protrusion 323, which is located on the same side of the first main body layer 31 as the first protrusion 321. The sixth protrusion 323 is annular and surrounds the first protrusion 321. The sixth protrusion 323 can be used for vacuum sealing.

[0053] Specifically, a sixth protrusion 323 is formed by patterning one side of the first protrusion 321 formed on the first main body layer 31. The height of the sixth protrusion 323 can be the same as the height of the first protrusion 321, and the sixth protrusion 323 can be formed in the same process step as the first protrusion 321.

[0054] After step S200, a first structural layer 30 is obtained, comprising a first main body layer 31, a first protrusion 321, a fourth protrusion 322, and a sixth protrusion 323. The material of the first structural layer 30 may be silicon.

[0055] In one embodiment, step S300 can yield the following result: Figure 4 The structure shown. (As illustrated) Figure 4 As shown, the first protrusion 321 contacts and is bonded to the first substrate 10. In step S300, bonding the first substrate 10 to the first structural layer 30 includes using an anodic bonding process to bond the first protrusion 321 to the first substrate 10. The anodic bonding process avoids changes in the height of the first protrusion 321 and the thickness of the first substrate 10 after bonding, thereby ensuring that the difference between the height of the first protrusion 321 and the thickness of the first electrode 20 remains unchanged before and after bonding. In other embodiments, other bonding processes can also be used to bond the first protrusion 321 to the first substrate 10, as long as the height of the first protrusion 321 and the thickness of the first substrate 10 do not change during the bonding process.

[0056] In one embodiment, step S300, the step of bonding the first substrate 10 to the first structural layer 30, further includes: bonding the fourth protrusion 322 to the first substrate 10 using an anodic bonding process, and after the fourth protrusion 322 is bonded to the first substrate 10, the fourth protrusion 322 contacts the first electrode 20 to achieve electrical connection. Step S300 further includes: bonding the sixth protrusion 323 to the first substrate 10 using an anodic bonding process.

[0057] The thickness of the first main body layer 31 is the same at all points, and the heights of the first protrusion 321, the fourth protrusion 322, and the sixth protrusion 323 are all equal. Through anodic bonding, the first protrusion 321, the fourth protrusion 322, and the sixth protrusion 323 can all contact and bond with the first substrate 10 in a single bonding process, thereby simplifying the process flow.

[0058] In one embodiment, after bonding the first substrate 10 to the first structural layer 30, the surface of the first main layer 31 away from the first protrusion 321 can be thinned to ensure that the thickness of the first main layer 31 is the same everywhere, thereby adjusting the first main layer 31 to the required thickness. This step can achieve the following: Figure 5 The structure shown.

[0059] In one embodiment, after forming the second protrusion in step S400, the following can be obtained: Figure 6 The structure shown. (As illustrated) Figure 6 As shown, the second protrusion 421 is located on the side of the second main body layer 41 away from the first protrusion 321. In some embodiments, the step of processing the first main body layer to form the second main body layer 41 and the second protrusion 421 located on the side of the second main body layer 41 away from the first protrusion 321 specifically includes: etching the side of the first main body layer away from the first protrusion 321 by photolithography to form the second protrusion 421.

[0060] Furthermore, such as Figure 6 As shown, in step S400, during the processing of the first main body layer, a third protrusion 422 is also formed on the side of the second main body layer 41 away from the first protrusion 321. The third protrusion 422 can be formed in the same process step as the second protrusion 421, and the heights of the third protrusion 422 and the second protrusion 421 are equal.

[0061] In one embodiment, after forming the second protrusion 421, step S400 further includes: forming a third bonding structure on the surface of the second body layer 41 away from the first protrusion 321, through which the following can be obtained: Figure 7 The structure shown. (As illustrated) Figure 7 As shown, each of the second main body layers 41 has a third bonding structure 503 on its surface away from the first protrusion 321. The material of the third bonding structure 503 can be a gold-tin alloy.

[0062] In one embodiment, step S400 further includes: performing a patterning process on the second main body layer 41 to form a mass structure and a connecting portion. Step S400 yields the following: Figure 8 The structure shown is as follows: Figure 8 As shown, the second main body layer 41 includes a mass structure 411 and a connecting portion 412; the mass structure 411 is located between the first electrode and the second electrode to form a capacitor with the first electrode and the second electrode respectively. The connecting portion 412 is used to connect structures such as protrusions located on both sides of the second main body layer 41. Figure 8In the embodiment shown, the connecting portion 412 includes a first sub-connecting portion 4121 connecting the first protrusion 321 and the second protrusion 421, a second sub-connecting portion 4122 connecting the third protrusion 422 and the fourth protrusion 322, and a third sub-connecting portion 4123 connecting the sixth protrusion 323 and the third bonding structure 503.

[0063] It should be noted that the thickness of the second main layer 41 is equal at all points, that is, the thickness of the mass structure 411 and the connecting part 412 is equal.

[0064] In one embodiment, step S500 specifically includes forming a metal electrode layer on the second surface 111 of the second substrate 11, and etching the metal electrode layer to form a second electrode using a patterning process. In this embodiment, the second substrate 11 may be a glass substrate.

[0065] In step S500, the difference between the height of the second protrusion 421 and the thickness of the second electrode 21 is equal to the difference between the height of the first protrusion 321 and the thickness of the first electrode 20. Specifically, it can be set such that the thickness of the first electrode 20 is equal to the thickness of the second electrode 21; and the height of the first protrusion 321 is equal to the height of the second protrusion 421.

[0066] Further, before bonding the second substrate 11 to the second structural layer 40, step S500 further includes: forming a first conductive line 61 and a second conductive line 62 on the second surface 111 of the second substrate 11. The first conductive line is as follows... Figure 9 and Figure 10 As shown, the second wire 62 is electrically connected to the second electrode 21. The first wire 61, the second wire 62, and the second electrode 21 can be formed simultaneously in the same process step.

[0067] Furthermore, such as Figure 11 As shown, after step S500, the preparation method further includes: forming an insulating layer 70, the insulating layer 70 covering a portion of the first conductor 61 and a portion of the second conductor 63.

[0068] Furthermore, such as Figure 12 As shown, after step S500, the fabrication method further includes forming a fourth bonding structure 504 on the surface of the insulating layer 70 away from the second substrate 11. The fourth bonding structure 504 may be a gold-tin solder.

[0069] In one embodiment, before bonding the second substrate 11 to the second structural layer 40, the sum of the maximum distance from the surface of the fourth bonding structure 504 away from the second substrate 11 to the second surface 111 of the second substrate 11 and the thickness of the third bonding structure 503 is greater than the height of the second protrusion 421.

[0070] In step S600, when bonding the second substrate 11 to the second structural layer 40, the third bonding structure 503 and the fourth bonding structure 504 are aligned and bonded together. At this time, the second protrusion 421 and the third protrusion 422 are not in contact with the second substrate 11. During the bonding process, the third bonding structure 503 and the fourth bonding structure 504 melt, reducing their combined thickness, thus bringing the second protrusion 421 and the third protrusion 422 into contact with the second substrate 11. Step S600 yields the following result: Figure 13 The structure shown. (As illustrated) Figure 13 As shown, the third bonding structure 503 and the fourth bonding structure 504 are bonded together to form a bonding portion 506. The height of the bonding portion 506 is the same as the height of the second protrusion 421, thereby ensuring that while packaging the semiconductor structure, the distance between the surface of the mass structure 411 facing the first substrate 10 and the first electrode 20 is equal to the distance between the surface of the mass structure 411 facing the second substrate 11 and the second electrode 21.

[0071] After bonding is completed, the first protrusion 321 is connected to the second protrusion 421 through the first sub-connector 4121, the fourth protrusion 322 is connected to the third protrusion 422 through the second sub-connector 4122, and the sixth protrusion 323 is connected to the structure after the third bonding structure 503 and the fourth bonding structure 504 are fused through the second sub-connector 4123. The first wire 61 is electrically connected to the first electrode 20 in sequence through the third protrusion 422, the second sub-connector 4122 and the fourth protrusion 322.

[0072] In one embodiment, both the third bonding structure 503 and the fourth bonding structure 504 are annular bonding structures. The bonding portion 506 obtained after the third bonding structure 503 and the fourth bonding structure 504 are bonded is annular. The bonding portion 506 is connected to the third sub-connecting portion 4123. The bonding portion 506, the third sub-connecting portion 4123 and the sixth protrusion 323 together form a sealing ring. The sealing ring, the first substrate 10 and the second substrate 11 enclose a sealing space, and the sealing space is a vacuum.

[0073] In one embodiment, the bonding process used in step S600 may be glass frit bonding, metal eutectic bonding, metal solid-liquid diffusion bonding, etc.

[0074] This application also provides another method for preparing a semiconductor structure, which differs from the method described above in that:

[0075] In this embodiment, such as Figure 14As shown, in step S400, the first main body layer is processed to form a second main body layer 41 and a second protrusion 421 located on the side of the second main body layer 41 away from the first protrusion 321, but the third protrusion 422 is not formed. Specifically, the second protrusion 421 is formed by photolithography on the side of the first main body layer away from the first protrusion 321.

[0076] like Figure 15 As shown, after forming the second protrusion 421, step S400 further includes forming a first bonding structure 501 and a third bonding structure 503 on the surface of the second main body layer 41 away from the first protrusion 321. The materials of the first bonding structure 501 and the third bonding structure 503 may be gold-tin alloy.

[0077] In this embodiment, such as Figure 16 As shown, step S400 further includes: performing a patterning process on the second main body layer 41 to form a mass structure 411 and a connecting portion 412. The mass structure 411 is located between the first electrode and the second electrode to form a capacitor with the first electrode and the second electrode respectively. The connecting portion 412 is used to connect structures such as protrusions located on both sides of the second main body layer 41. Figure 16 In the embodiment shown, the connecting portion 412 includes a first sub-connecting portion 4121 connecting the first protrusion 321 and the second protrusion 421, a second sub-connecting portion 4122 connecting the first bonding structure 501 and the fourth protrusion 322, and a third sub-connecting portion 4123 connecting the sixth protrusion 323 and the third bonding structure 503.

[0078] In this embodiment, such as Figure 17 As shown, step S500 further includes: forming a second bonding structure 502 on one side of the second substrate 11, the second bonding structure 502 being located on the same side of the second surface 111 as the second electrode 21. A fourth bonding structure 504 is formed on the surface of the insulating layer 70 away from the second substrate 11.

[0079] In this embodiment, in step S600, when bonding the second substrate 11 to the second structural layer 40, the first bonding structure 501 and the second bonding structure 502 are aligned and bonded, and the third bonding structure 503 and the fourth bonding structure 504 are aligned and bonded. At this time, the second protrusion 421 2 is not in contact with the second substrate 11. During the bonding process, the first bonding structure 501 and the second bonding structure 502 melt; the third bonding structure 503 and the fourth bonding structure 504 melt, and their combined thickness decreases, causing the second protrusion 421 to contact the second substrate 11. Step S600 yields the following result: Figure 18 The structure shown. (As illustrated) Figure 18As shown, the first bonding structure 501 and the second bonding structure 502 are bonded to form a bonding portion 505, and the third bonding structure 503 and the fourth bonding structure 504 are bonded to form a bonding portion 506. The heights of the bonding portion 505, the bonding portion 506, and the second protrusion 421 are all the same, thereby ensuring that while packaging the semiconductor structure, the distance between the surface of the mass structure 411 facing the first substrate 10 and the first electrode 20 is equal to the distance between the surface of the mass structure 411 facing the second substrate 11 and the second electrode 21.

[0080] After bonding is completed, the first protrusion 321 is connected to the second protrusion 421 through the first sub-connector 4121, the fourth protrusion 322 is connected to the structure formed by the fusion of the first bonding structure 501 and the second bonding structure 502 through the second sub-connector 4122, and the sixth protrusion 323 is connected to the structure formed by the fusion of the third bonding structure 503 and the fourth bonding structure 504 through the second sub-connector 4123. The first wire 61 is electrically connected to the first electrode 20 in sequence through the third protrusion 422, the second sub-connector 4122, and the fourth protrusion 322.

[0081] This application also provides another method for preparing a semiconductor structure, which differs from the aforementioned methods in that:

[0082] In this embodiment, such as Figure 19 and Figure 20 As shown, the second protrusion 421 includes a first sub-protrusion 4211 and a second sub-protrusion 4212 located on the side of the first sub-protrusion 4211 away from the second main body layer 41. Figure 19 As shown, in step S400, the surface of the first main body layer away from the first protrusion 321 is etched to obtain a third main body layer 41' and a second sub-protrusion 4212 located on the side of the third main body layer 41' away from the first protrusion 321. Then, as... Figure 20 As shown, the surface of the third main body layer 41' facing the second sub-protrusion 4212 is etched to obtain the second main body layer 41 and the first sub-protrusion 4211 located between the second main body layer 41 and the second sub-protrusion 4212.

[0083] Furthermore, such as Figure 20 As shown, in step S400, during the process of processing the third main body layer, a third protrusion 422 is also formed on the side of the second main body layer 41 away from the first protrusion 321, and the height of the third protrusion 422 is less than the height of the second protrusion 421.

[0084] Further, step S400 also includes: forming a fifth protrusion 423 located on the side of the second main body layer 41 away from the first protrusion 321, the fifth protrusion 423 being annular and surrounding the first protrusion 321. The fifth protrusion 423, the third protrusion 422, and the first sub-protrusion 4211 have the same height and are formed in the same process step.

[0085] In this embodiment, such as Figure 21 As shown, after forming the second protrusion 421, the fifth protrusion 423 and the third protrusion 422, step S400 further includes: forming a first bonding structure 501 on the surface of the third protrusion 422 away from the first substrate 10, and forming a third bonding structure 503 on the surface of the fifth protrusion 423 away from the first substrate 10.

[0086] In this embodiment, such as Figure 22 As shown, step S400 further includes: performing a patterning process on the second main body layer 41 to form a mass structure 411 and a connecting portion 412. The mass structure 411 is used to form a capacitor between the first electrode and the second electrode. The connecting portion 412 is used to connect structures such as protrusions located on both sides of the second main body layer 41. Figure 22 In the embodiment shown, the connecting portion 412 includes a first sub-connecting portion 4121 connecting the first protrusion 321 and the first sub-protrusion 4211, a second sub-connecting portion 4122 connecting the third protrusion 422 and the fourth protrusion 322, and a third sub-connecting portion 4123 connecting the fifth protrusion 423 and the sixth protrusion 323.

[0087] In this embodiment, such as Figure 23 As shown, step S500 further includes: forming a second bonding structure 502 on one side of the second substrate 11, the second bonding structure 502 being located on the same side of the second surface 111 as the second electrode 21. A fourth bonding structure 504 is formed on the surface of the insulating layer 70 away from the second substrate 11.

[0088] In this embodiment, step S600 includes bonding the first bonding structure 501 and the second bonding structure 502, and bonding the third bonding structure 503 and the fourth bonding structure 504, so that the second substrate 11 is bonded to the second structural layer. Step S600 yields the following result: Figure 24 The structure shown. (As illustrated) Figure 24 As shown, the first bonding structure 501 and the second bonding structure 502 are bonded together to form a bonding portion 505, and the third bonding structure 503 and the fourth bonding structure 504 are bonded together to form a bonding portion 506. The height of the bonding portion 505, the height of the bonding portion 506 and the height of the first sub-protrusion 4211 are all the same.

[0089] In this embodiment, such as Figure 25As shown, before the second substrate 11 is bonded to the second structural layer 40, the sum of the thickness of the first bonding structure 501, the thickness of the portion of the second bonding structure 502 in contact with the second substrate 11, and the thickness of the third protrusion 422 is greater than the thickness of the second protrusion 421. Specifically, a portion of the second bonding structure 502 is located above the first conductive line 61, while another portion directly contacts the second substrate 11.

[0090] exist Figure 25 In the illustrated embodiment, the thickness H1 of the first protrusion 321 is equal to the thickness H2 of the second protrusion 421. The thickness H3 of the first sub-protrusion 4211 is equal to the thickness H5 of the third protrusion 422. The sum H6 of the thickness of the first bonding structure 501 and the maximum thickness of the second bonding structure 502 is greater than the thickness of the second sub-protrusion 4212.

[0091] During the bonding process between the second substrate 11 and the second structural layer 40, the first bonding structure 501 and the second bonding structure 502 melt, and their combined thickness H6 decreases, while the thickness H2 of the second protrusion 421 remains unchanged. Finally, the second protrusion 421 contacts the second surface 111. By lowering the bonding temperature, the first bonding structure 501 and the second bonding structure 502 are solidified to form a bonding portion, thus completing the bonding.

[0092] In this embodiment, both the third bonding structure 503 and the fourth bonding structure 504 are annular bonding structures. The bonding portion 506 obtained after the third bonding structure 503 and the fourth bonding structure 504 are bonded is annular. The bonding portion 506 is connected to the fifth protrusion 423. The bonding portion 506, the fifth protrusion 423, the third sub-connecting portion 4123 and the sixth protrusion 323 together form a sealing ring. The sealing ring, the first substrate 10 and the second substrate 11 enclose a sealing space, and the sealing space is a vacuum.

[0093] It should be noted that the technical solutions or features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for fabricating a semiconductor structure, characterized in that, include: A first electrode is formed on a first surface of a first substrate; Forming the first structural layer; The first structural layer includes a first main body layer and a first protruding pillar located on one side of the first main body layer; The first substrate is bonded to the first structural layer, so that the first protrusion contacts the first surface, and the height of the first protrusion remains unchanged; The first main body layer is processed to form a patterned second main body layer and a second and a third protrusion located on the side of the second main body layer away from the first protrusion, resulting in a second structural layer including the second main body layer, the third protrusion, the second protrusion, and the first protrusion; the height of the third protrusion is less than the height of the second protrusion; the second main body layer includes a mass structure; the orthographic projection of the mass structure on the first surface at least partially overlaps with the orthographic projection of the first electrode on the first surface; A second electrode is formed on the second surface of the second substrate; the difference between the height of the second protrusion and the thickness of the second electrode is equal to the difference between the height of the first protrusion and the thickness of the first electrode. A first bonding structure is formed on the side of the third protrusion away from the first protrusion; a second bonding structure is formed on one side of the second substrate, the second bonding structure and the second electrode being located on the same side of the second surface; the sum of the thickness of the first bonding structure, the thickness of the portion of the second bonding structure in contact with the second substrate, and the thickness of the third protrusion is greater than the thickness of the second protrusion. The first bonding structure is bonded to the second bonding structure, and the first bonding structure and the second bonding structure are melted, reducing their combined thickness, so that the second protrusion contacts the second surface; the second substrate is bonded to the second structural layer, so that the second protrusion contacts the second surface, and the height of the second protrusion remains unchanged; the orthographic projection of the second electrode on the first surface coincides with the orthographic projection of the first electrode on the first surface.

2. The method for preparing a semiconductor structure according to claim 1, characterized in that, The bonding of the first substrate to the first structural layer includes: The first protrusion is bonded to the first substrate using an anodic bonding process.

3. The method for preparing a semiconductor structure according to claim 1, characterized in that, The second protrusion includes a first sub-protrusion and a second sub-protrusion located on the side of the first sub-protrusion away from the second main body layer; the first sub-protrusion and the third protrusion have the same height and are formed synchronously.

4. The method for preparing a semiconductor structure according to claim 3, characterized in that, The processing of the first main body layer includes: The surface of the first main body layer away from the first protrusion is etched to obtain a third main body layer and a second sub-protrusion located on the side of the third main body layer away from the first protrusion. The surface of the third main body layer facing the second sub-protrusion is etched to obtain the second main body layer and the first sub-protrusion and the third protrusion located between the second main body layer and the second sub-protrusion.

5. The method for preparing a semiconductor structure according to claim 1, characterized in that, Before bonding the second substrate to the second structural layer, the fabrication method further includes: forming a first bonding structure on the surface of the two main layers away from the first protrusion, the first bonding structure being in direct contact with the second main layer; and forming a second bonding structure on one side of the second substrate, the second bonding structure being located on the same side of the second surface as the second electrode. The step of bonding the second substrate to the second structural layer includes: bonding the first bonding structure to the second bonding structure, thereby bonding the second substrate to the second structural layer.

6. The method for preparing a semiconductor structure according to claim 1, characterized in that, Before bonding the second substrate to the second structural layer, the method for fabricating the semiconductor structure further includes: forming a first conductive line on the second surface of the second substrate; The material of the second structural layer is a semiconductor material; the second bonding structure covers a portion of the first wire; the second main body layer includes a connecting portion connected to the third protrusion, and the second structural layer also includes a fourth protrusion connected to the connecting portion; the fourth protrusion and the first protrusion are located on the same side of the second main body layer and are in contact with the first electrode.

7. The method for preparing a semiconductor structure according to claim 1, characterized in that, The material of the second structural layer is a semiconductor material; the second structural layer further includes a fifth protrusion located on the side of the second main layer away from the first protrusion, the fifth protrusion being annular and surrounding the second protrusion; before bonding the second substrate to the second structural layer, the fabrication method further includes: A first wire and a second wire are formed on the second surface of the second substrate; the second wire is electrically connected to the second electrode. An insulating layer is formed, which covers a portion of the first conductor and a portion of the second conductor; A third bonding structure is formed on the surface of the fifth protrusion away from the first protrusion, and a fourth bonding structure is formed on the surface of the insulating layer away from the second substrate; The step of bonding the second substrate to the second structural layer includes: bonding the third bonding structure to the fourth bonding structure; after the second substrate is bonded to the second structural layer, the first wire is electrically connected to the first electrode.

8. The method for preparing a semiconductor structure according to claim 1, characterized in that, The first structural layer further includes a sixth protruding post, which is located on the same side of the first main body layer as the first protruding post; the sixth protruding post is annular and surrounds the first protruding post; The bonding of the first substrate to the first structural layer includes: Anodizing bonding process is used to bond the first protrusion and the sixth protrusion to the first substrate, respectively.

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