A bonding structure and forming method for MEMS micromirror

Abstract

The present application discloses a bonding structure and a forming method for a MEMS micromirror, comprising an SOI substrate, a patterned bonding layer, a bonding substrate and an isolation groove structure, wherein the patterned bonding layer is located between the SOI substrate and the bonding substrate; the SOI substrate has a plurality of metal interconnect structures that penetrate vertically, and a dielectric layer is provided between the metal interconnect structure and the SOI substrate; at least a portion of the patterned bonding layer is located on the metal interconnect structure, and the metal interconnect structure and the bonding substrate are electrically connected through the patterned bonding layer; the isolation groove structure penetrates the patterned bonding layer and the bonding substrate vertically, and exposes the dielectric layer on the peripheral side of at least a portion of the metal interconnect structures in the plurality of metal interconnect structures. The present application introduces a patterned bonding layer with a certain thickness and pattern between the SOI substrate and the bonding substrate, avoids the undesired adhesion between the two layers of silicon materials in the vertical direction, improves the isolation effectiveness of the SOI substrate and the bonding substrate, and further improves the reliability and stability of electrical isolation applied to the MEMS micromirror.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a bonding structure and a forming method for a MEMS micromirror. Background Art

[0002] In the manufacturing process of MEMS micromirrors, SOI substrates and silicon substrates are usually used as the materials for the lower comb teeth and upper comb teeth respectively, and the two layers of silicon materials are connected by a silicon-silicon bonding process; however, the silicon-silicon bonding process has great limitations and can only be used for the design of front signal lead-out. When the TSV process is used to connect the bottom signal, although the signal interconnection between the bottom pad and the multi-layer silicon material can be easily achieved, the direct TSV interconnection on the silicon-silicon bonding process is prone to undesired adhesion between the multi-layer silicon materials, and effective electrical isolation cannot be achieved at the same time. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present application provides a bonding structure and a forming method for a MEMS micromirror. The technical solution is as follows:

[0004] On the one hand, the present application provides a bonding structure for a MEMS micromirror, comprising an SOI substrate, a patterned bonding layer, a bonding substrate and an isolation groove structure, wherein the patterned bonding layer is located between the SOI substrate and the bonding substrate;

[0005] The SOI substrate includes a first functional area for forming lower comb teeth of a MEMS micromirror, and the bonding substrate includes a second functional area for forming upper comb teeth of a MEMS micromirror, and the first functional area and the second functional area are electrically isolated in a vertical direction by the patterned bonding layer;

[0006] The SOI substrate has a plurality of metal interconnect structures running vertically therethrough, and a dielectric layer is provided between the metal interconnect structures and the SOI substrate;

[0007] At least a portion of the patterned bonding layer is located on the metal interconnect structure, and the metal interconnect structure is electrically connected to the bonding substrate through the patterned bonding layer;

[0008] The isolation trench structure vertically penetrates the patterned bonding layer and the bonding substrate, and exposes the dielectric layer on the peripheral side of at least a portion of the metal interconnection structures among the plurality of metal interconnection structures.

[0009] Furthermore, the multiple metal interconnect structures include a first interconnect structure, a contact window penetrating the dielectric layer is opened on the surface of the SOI substrate, and an end of the first interconnect structure is located in the contact window, so that the first interconnect structure is electrically connected to the first functional area in the SOI substrate through the contact window.

[0010] Furthermore, the SOI substrate includes a first substrate layer and a second substrate layer, the thickness of the first substrate layer is smaller than that of the second substrate layer, the first functional area is located in the first substrate layer, and the contact window is located on a surface of the first substrate layer facing away from the second substrate layer.

[0011] Further, a lateral dimension of an end of the contact window close to the bonding substrate is larger than a lateral dimension of an end of the contact window away from the bonding substrate.

[0012] Furthermore, the contact window is located in a projection area of ​​an inner side wall of the isolation trench structure.

[0013] Furthermore, the patterned bonding layer includes a first bonding area, the bonding substrate includes an isolation area, the first bonding area and the isolation area are both located on the first interconnection structure, and the isolation groove structure is surrounded by the first bonding area and the isolation area so that the first bonding area is isolated from the structural bonding area of ​​the patterned bonding layer, and the isolation area is isolated from the bonding substrate.

[0014] Furthermore, the plurality of metal interconnect structures include a second interconnect structure, and the second interconnect structure and the first functional area in the SOI substrate are isolated from each other by the dielectric layer.

[0015] Furthermore, the plurality of metal interconnect structures include a first interconnect structure, the first interconnect structure is electrically connected to a first functional region in the SOI substrate, and the second interconnect structure is flush with a surface of the first interconnect structure.

[0016] Furthermore, the patterned bonding layer also includes a second bonding area isolated from the structural bonding area of ​​the patterned bonding layer, and the second bonding area is located on the second interconnection structure of the multiple metal interconnection structures, so that the second interconnection structure is electrically connected to the second functional area of ​​the bonding substrate through the second bonding area.

[0017] Furthermore, the patterned bonding layer includes a structural bonding area and a vacuum bonding cavity, the structural bonding area is a closed surface, and the vacuum bonding cavity is located between the SOI substrate, the structural bonding area and the bonding substrate.

[0018] Furthermore, the patterned bonding layer satisfies at least one of the following characteristics:

[0019] The material of the patterned bonding layer includes metal;

[0020] The longitudinal dimension of the patterned bonding layer is 500nm-600nm.

[0021] On the other hand, the present application also provides a method for forming a bonding structure for a MEMS micromirror, comprising:

[0022] A patterned bonding layer is formed on an SOI substrate; the SOI substrate has a plurality of metal interconnect structures running vertically therethrough, a dielectric layer is provided between the metal interconnect structure and the SOI substrate, and at least a portion of the patterned bonding layer is located on the metal interconnect structure;

[0023] The surface of the SOI substrate having the patterned bonding layer is bonded to a bonding substrate to obtain a bonding structure; the metal interconnection structure is electrically connected to the bonding substrate through the patterned bonding layer; the SOI substrate includes a first functional area for forming the lower comb teeth of the MEMS micromirror, and the bonding substrate includes a second functional area for forming the upper comb teeth of the MEMS micromirror, and the first functional area and the second functional area are electrically isolated in the vertical direction by the patterned bonding layer;

[0024] The bonding structure is etched to form an isolation groove structure to obtain a bonding structure for a MEMS micromirror; the isolation groove structure vertically penetrates the patterned bonding layer and the bonding substrate and exposes the dielectric layer on the peripheral side of at least part of the metal interconnection structures among the multiple metal interconnection structures.

[0025] Furthermore, before forming the patterned bonding layer on the SOI substrate, the method further comprises:

[0026] Etching an SOI substrate having a plurality of through holes to form contact windows at ends of at least some of the through holes; the contact windows penetrate the dielectric layer at the ends of the through holes;

[0027] A plurality of metal interconnect structures are formed in an SOI substrate having a contact window formed therein; the metal interconnect structures are filled in through holes, and the plurality of metal interconnect structures include a first interconnect structure, and the first interconnect structure is electrically connected to a first functional area in the SOI substrate through the contact window.

[0028] Implementing this application has the following beneficial effects:

[0029] The bonding structure for the MEMS micromirror of the present application introduces a patterned bonding layer between the SOI substrate and the bonding substrate. The patterned bonding layer has a certain thickness and pattern, and can highly control the SOI substrate and the bonding substrate in the vertical direction, avoiding the undesired adhesion between the two layers of silicon material in the traditional bonding process, and effectively improving the isolation effectiveness between the SOI substrate and the bonding substrate. When applied to the MEMS micromirror, it can effectively achieve electrical isolation between the lower comb teeth formed based on the SOI substrate and the upper comb teeth formed based on the bonding substrate, thereby improving the reliability and stability of the electrical isolation. At the same time, an isolation groove structure is opened in the bonding structure for the MEMS micromirror, so that good electrical interconnection is achieved between the SOI substrate and part of the metal interconnection structure, and between the bonding substrate and another part of the metal interconnection, respectively. At the same time, the SOI substrate and the bonding substrate still maintain good electrical isolation, which is conducive to reducing the bonding structure for the MEMS micromirror and the preparation cost of the MEMS micromirror. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the embodiments, wherein the same components are represented by the same reference numerals. Obviously, the drawings described below are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A structural schematic diagram of a bonding structure for a MEMS micromirror provided in an embodiment of the present application;

[0032] Figure 2 A top view of a bonding structure for a MEMS micromirror provided in an embodiment of the present application;

[0033] Figure 3 A schematic structural diagram of an SOI substrate having a plurality of through holes provided in an embodiment of the present application;

[0034] Figure 4 A schematic structural diagram of an SOI substrate with a contact window provided in an embodiment of the present application;

[0035] Figure 5 A schematic structural diagram of an SOI substrate having a metal interconnect structure provided in an embodiment of the present application;

[0036] Figure 6 A schematic structural diagram of an SOI substrate with a patterned bonding layer provided in an embodiment of the present application.

[0037] Wherein, the accompanying drawings are marked as follows:

[0038] 100-SOI substrate, 101-first substrate layer, 1010-first functional area, 102-second substrate layer, 103-dielectric layer, 110-through hole, 120-contact window, 200-patterned bonding layer, 201-first bonding area, 202-second bonding area, 203-structural bonding area, 204-vacuum bonding cavity, 205-cutting groove area, 300-bonding substrate, 301-isolation area, 302-second functional area, 400-isolation groove structure, 500-metal interconnection structure, 501-first interconnection structure, 502-second interconnection structure. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments, and therefore cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0040] It should be noted that in the description of the present application, for the following defined terms, unless a different definition is given in the claims or elsewhere in this specification, these definitions should be applied. All numerical values, whether or not explicitly indicated, are defined herein as being modified by the term "about". The term "about" generally refers to a numerical range that a person of ordinary skill in the art would consider to be equivalent to the stated value to produce substantially the same properties, functions, results, etc. A numerical range indicated by a low value and a high value is defined to include all numerical values ​​included in the numerical range and all subranges included in the numerical range.

[0041] It should be noted that the terms "first", "second", etc. in the specification, claims and drawings of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the objects used in this way can be interchanged where appropriate, so that the embodiments of the present application can be implemented in a sequence other than the following diagrams or the following descriptions. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, or products.

[0042] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that the depth direction of an element or layer is the direction perpendicular to the surface of the element or layer, and the direction of the cross section of an element or layer is the direction parallel to the surface of the element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When discussing a second element, component, region, layer or section, it does not necessarily mean that the first element, component, region, layer or section must be present.

[0043] In the MEMS micromirror manufacturing process, in order to avoid the interference problem caused by the front signal lead-out structure, a through silicon via (TSV) process can be introduced, but the two layers of silicon material used to form the upper comb teeth and the lower comb teeth of the MEMS micromirror are often connected through a silicon-silicon bonding process, and direct TSV interconnection on the silicon-silicon bonding process cannot achieve effective electrical isolation; in order to solve this problem, the embodiment of the present application provides a bonding structure and a formation method for a MEMS micromirror, which are used to prepare a MEMS micromirror, such as Figure 1 As shown, the bonding structure for the MEMS micromirror includes an SOI substrate, a patterned bonding layer, a bonding substrate and an isolation groove structure, wherein the patterned bonding layer is located between the SOI substrate and the bonding substrate; the SOI substrate has a plurality of metal interconnect structures running vertically therethrough, and a dielectric layer is provided between the metal interconnect structure and the SOI substrate; at least a portion of the patterned bonding layer is located on the metal interconnect structure, and the metal interconnect structure is electrically connected to the bonding substrate through the patterned bonding layer; the isolation groove structure runs vertically through the patterned bonding layer and the bonding substrate, and exposes the dielectric layer on the peripheral side of at least a portion of the metal interconnect structures among the plurality of metal interconnect structures.

[0044] In this way, the bonding structure for the MEMS micromirror can achieve effective connection between the SOI substrate and the bonding substrate through the patterned bonding layer, avoiding the adverse effects of the metal interconnection structure on the electrical isolation between the two layers of silicon materials. At the same time, a certain height control is performed through the patterned bonding layer to avoid unexpected adhesion between the SOI substrate and the bonding substrate during the bonding process, especially to avoid unexpected adhesion between the first functional area in the SOI substrate used to form the lower comb teeth of the MEMS micromirror and the second functional area in the bonding substrate used to form the upper comb teeth of the MEMS micromirror, thereby improving the effectiveness and reliability of electrical isolation between the first functional area and the second functional area in the vertical direction through the patterned bonding layer; when the bonding structure for the MEMS micromirror is applied to the preparation process of the MEMS micromirror, good electrical isolation can also be formed between the lower comb teeth formed based on the SOI substrate and the upper comb teeth formed based on the bonding substrate, thereby greatly improving the effectiveness and reliability of electrical isolation.

[0045] The method for forming a bonding structure for a MEMS micromirror is used to prepare the bonding structure for a MEMS micromirror. First, a patterned bonding layer is formed on an SOI substrate with a metal interconnection structure to achieve connection between the SOI substrate and the patterned bonding layer; then, the surface of the SOI substrate with the patterned bonding layer is bonded to the bonding substrate to obtain a bonding structure. During the bonding process, the patterned bonding layer has a certain thickness, which can effectively reduce unexpected adhesion between the SOI substrate and the bonding substrate, and improve the effectiveness and reliability of electrical isolation in the vertical direction; then, the bonding structure is etched to form an isolation groove structure, and the isolation groove structure is surrounded by the peripheral side of some metal interconnection structures among a plurality of metal interconnection structures to prevent the adverse effects of TSV interconnection on electrical isolation, and further improve the reliability and stability of electrical isolation between the SOI substrate and the bonding substrate in the bonding structure for the MEMS micromirror.

[0046] Combine the following Figure 1-2 The bonding structure for the MEMS micromirror according to the embodiment of the present application is described in detail.

[0047] Specifically, Figure 1 As shown, the bonding structure for the MEMS micromirror includes an SOI substrate 100, wherein, in the longitudinal direction, the SOI substrate 100 includes a first substrate layer 101 and a second substrate layer 102, the thickness of the first substrate layer 101 is less than the thickness of the second substrate layer 102, and the first substrate layer 101 is used to form lower comb teeth in the subsequent process of preparing the MEMS micromirror. Further, the first substrate layer 101 includes a first functional area 1010, and the first functional area 1010 is used to form the lower comb teeth of the MEMS micromirror. The second substrate layer 102 has a large thickness and can serve as a substrate layer of the MEMS micromirror, play a good supporting role, and improve the reliability and stability of the overall structure.

[0048] The SOI substrate 100 has a plurality of metal interconnect structures 500 running vertically therethrough, the metal interconnect structures 500 running through the first substrate layer 101 and the second substrate layer 102, with one end exposed to the surface of the SOI substrate 100 close to the first substrate layer 101, and the other end exposed to the surface of the SOI substrate 100 close to the second substrate layer 102, so that both side surfaces of the SOI substrate 100 can be electrically connected through the metal interconnect structures 500, which is beneficial to the effectiveness and reliability of electrical connections in subsequent MEMS micromirrors.

[0049] It should be noted that dielectric layers 103 are provided on the surface of the SOI substrate 100, between the first substrate layer 101 and the second substrate layer 102, and between the metal interconnect structure 500 and the SOI substrate 100 to isolate each other. In some exemplary embodiments, at least a portion of the dielectric layer 103 is located on the surface of the SOI substrate 100, including but not limited to a side surface of the SOI substrate 100 close to the first substrate layer 101 and a side surface of the SOI substrate 100 close to the second substrate layer 102, wherein the side surface of the SOI substrate 100 close to the first substrate layer 101 and the side surface of the SOI substrate 100 close to the second substrate layer 102 are located. The dielectric layer 103 on one side surface of a substrate layer 101 can effectively isolate the SOI substrate 100 from the patterned bonding layer 200 to avoid cross interference caused by unexpected breakdown, and the metal interconnection structure 500 can penetrate the dielectric layers 103 on both surfaces of the SOI substrate 100 in the vertical direction, that is, the two ends of the metal interconnection structure 500 are respectively exposed to the dielectric layers 103 on the corresponding surfaces to avoid the obstruction of the dielectric layer 103 and affect the electrical connection reliability between the metal interconnection structure 500 and the patterned bonding layer 200 and the bonding substrate 300.

[0050] like Figure 1 As shown, in some exemplary embodiments, at least a portion of the dielectric layer 103 is located between the first substrate layer 101 and the second substrate layer 102, and the portion of the dielectric layer 103 is the dielectric material of the SOI substrate 100, so as to effectively isolate the first substrate layer 101 and the second substrate layer 102, prevent undesired interference between the two, and have a good electrical isolation effect; in other exemplary embodiments, at least a portion of the dielectric layer 103 is located between the metal interconnect structure 500 and the SOI substrate 100, so that both the first substrate layer 101 and the second substrate layer 102 in the SOI substrate 100 can be laterally isolated from the metal interconnect structure 500, thereby improving isolation reliability.

[0051] Specifically, Figure 1As shown, the plurality of metal interconnect structures 500 include a first interconnect structure 501, which is used to electrically connect to the first functional area 1010 in the SOI substrate 100, specifically, to electrically connect to the lower comb teeth that can be formed in the subsequent process; accordingly, a contact window 120 penetrating the dielectric layer 103 is opened on the surface of the SOI substrate 100, and the contact window 120 penetrates the dielectric layer 103 between the end of the first interconnect structure 501 and the first substrate layer 101 to expose the silicon material of the first functional area 1010 in the first substrate layer 101, and the end of the first interconnect structure 501, That is, one end of the first interconnect structure 501 close to the first substrate layer 101 is located in the contact window 120. During the preparation process, the metal material of the first interconnect structure 501 can be filled in the contact window 120, which can effectively cover the contact window 120 and contact the silicon material of the first functional area 1010 exposed in the contact window 120, so that the first interconnect structure 501 is electrically connected to the silicon material of the first functional area 1010 through the contact window 120, thereby improving the electrical connection effectiveness and reliability between the first interconnect structure 501 and the first substrate layer 101 in the SOI substrate 100.

[0052] Specifically, the contact window 120 is located on a side surface of the first substrate layer 101 away from the second substrate layer 102, so that the contact window 120 is opened on the surface of the first substrate layer 101, effectively penetrating the dielectric layer 103 on the surface of the first substrate layer 101 away from the second substrate layer 102, ensuring that what is exposed through the contact window 120 is the silicon material of the first functional area 1010, thereby improving the accuracy and stability of the electrical connection in subsequent processes, and facilitating improving the bonding structure used for the MEMS micromirror and the performance of the MEMS micromirror.

[0053] Specifically, Figure 1As shown, the lateral dimension of the end of the contact window 120 close to the bonding substrate 300 is greater than the lateral dimension of the end of the contact window 120 away from the bonding substrate 300, that is, the lateral dimension of the end of the first interconnect structure 501 close to the first substrate layer 101, the end close to the second substrate layer 102 is smaller than the lateral dimension of the end away from the second substrate layer 102, the surface of the contact window 120 has a certain roughness, and the contact window 120 can be formed by etching while increasing the surface roughness, without adding additional steps, which is simple and convenient, and can increase the surface contact area between the seed layer and the silicon material of the first functional area 1010 in the first substrate layer 101 in the subsequent preparation process, so that the conductivity between the first interconnect structure 501 and the first functional area 1010 is better; and in the longitudinal direction, the longitudinal dimension of the contact window 120 is smaller than the longitudinal dimension of the first substrate layer 101 and the surface medium The sum of the longitudinal dimensions of the dielectric layer 103 is simple in the preparation process, short in time, and conducive to saving preparation costs. On the other hand, it can improve the effectiveness and reliability of the contact window 120 penetrating the dielectric layer 103 and exposing the first functional area 1010, and can also avoid the risk of excessive loss of the dielectric layer 103 causing undesired electrical connection to the second substrate layer 102, thereby improving the accuracy and reliability of electrical connection and electrical isolation. In some exemplary embodiments, the lateral dimension of the contact window 120 gradually increases in the direction away from the second substrate layer 102. In other exemplary embodiments, the lateral dimension of the contact window 120 gradually increases in a step-like manner in the direction away from the second substrate layer 102. In some preferred embodiments, the contact window 120 can be a funnel-shaped structure, and accordingly, the end of the first interconnect structure 501 close to the bonding substrate 300 is a funnel-shaped structure.

[0054] Specifically, the plurality of metal interconnect structures 500 include a second interconnect structure 502, which is used to be electrically connected to the bonding substrate 300, specifically, to be electrically connected to the second functional area 302 capable of forming upper comb teeth in a subsequent process; the second interconnect structure 502 and the first functional area 1010 are isolated from each other by the dielectric layer 103 to avoid crosstalk caused by an unexpected connection between the second interconnect structure 502 and the first substrate layer 101; in this way, the first interconnect structure 501 is electrically connected to the first substrate layer 101, and the second interconnect structure 502 is electrically connected to the bonding substrate 300, thereby improving the accuracy and reliability of the electrical connection and electrical isolation of each metal interconnect structure 500, which is beneficial to improving the performance accuracy and performance reliability of the MEMS micromirror formed in the subsequent process.

[0055] Specifically, the surfaces of the first interconnect structure 501 and the second interconnect structure 502 are flush; further, the surface of the first interconnect structure 501 exposed on the first substrate layer 101 side and the surface of the second interconnect structure 502 exposed on the first substrate layer 101 side are flush, and the surface of the first interconnect structure 501 exposed on the second substrate layer 102 side and the surface of the second interconnect structure 502 exposed on the second substrate layer 102 side are flush, which can improve the surface flatness of the multiple metal interconnect structures 500 and the surface between them and the SOI substrate 100 surface, which is beneficial to improving the flatness and stability of the bonding surface in the subsequent preparation process, and is beneficial to improving the bonding reliability, and further beneficial to improving the preparation yield and overall electrical performance of the MEMS micromirror.

[0056] Specifically, Figure 1 As shown, the patterned bonding layer 200 is located on the SOI substrate 100, one side of which is connected to the dielectric layer 103 on the surface of the SOI substrate 100, and the other side is bonded to the bonding substrate 300. At least a part of the patterned bonding layer 200 is located on the metal interconnect structure 500. The metal interconnect structure 500 and the bonding substrate 300 are electrically connected through the patterned bonding layer 200 to form a good electrical connection in the vertical direction, which is beneficial to the electrical connection reliability of the MEMS micromirror formed in the subsequent process.

[0057] Specifically, Figure 2 As shown, the graphic bonding layer 200 has a preset pattern, and different areas have different functions. It can provide a certain bonding area to improve the bonding strength, and can also provide a certain electrical connection channel in the vertical direction, so that the same layer of graphic bonding layer 200 can be used to realize structural bonding and electrical interconnection in different areas respectively, and different areas avoid each other and do not interfere with each other, which is beneficial to improving the bonding structure used for MEMS micromirrors and the overall structural reliability and preparation yield of the subsequently formed MEMS devices, and is also beneficial to reducing the difficulty of preparation and saving preparation costs.

[0058] Specifically, Figure 2 As shown, the patterned bonding layer 200 includes a structural bonding area 203 and a vacuum bonding cavity 204, wherein the structural bonding area 203 is surrounded by the vacuum bonding cavity 204, and the vacuum bonding cavity 204 is located between the SOI substrate 100, the structural bonding area 203 and the bonding substrate 300. The structural bonding area 203 is a closed surface, which can provide good bonding strength and support strength on the one hand, and facilitate the formation of high vacuum bonding inside on the other hand, thereby preventing the structure from bursting under the high pressure conditions of the subsequent vacuum process, which is beneficial to improving the bonding structure used for MEMS micromirrors and the preparation yield and structural accuracy of MEMS micromirrors.

[0059] Specifically, Figure 1 and Figure 2As shown, the patterned bonding layer 200 includes a first bonding area 201, which is located on the first interconnect structure 501 and is used to be electrically connected to the first interconnect structure 501, and part of the structure in the isolation groove structure 400 is surrounded by the first bonding area 201 and is laterally located between the first bonding area 201 and the structural bonding area 203, so that the first bonding area 201 is independent of the structural bonding area 203, that is, the first bonding area 201 and the structural bonding area 203 are isolated from each other, avoiding abnormal crosstalk between the first interconnect structure 501 and the bonding substrate 300 through the structural bonding area 203 during the subsequent electrical connection process, thereby improving device performance.

[0060] Specifically, Figure 1 As shown, the bonding substrate 300 includes an isolation region 301, which is located on the first interconnect structure 501. In the longitudinal direction, the first bonding area 201 is located between the isolation region 301 and the first interconnect structure 501, and the isolation groove structure 400 is surrounded by the peripheral side of the isolation region 301, so that the isolation region 301 is independent of the bonding substrate 300, that is, the isolation region 301 and the second functional area 302 of the bonding substrate 300 are isolated from each other. On the one hand, the isolation reliability is improved, and abnormal crosstalk between the first interconnect structure 501 and the bonding substrate 300 through the structural bonding area 203 is avoided during the subsequent electrical connection process, thereby improving the device performance; on the other hand, the step of removing the material of the isolation region 301 separately during the preparation process is relatively cumbersome. Only by opening the isolation groove structure 400, the isolation of the isolation region 301 can be quickly and effectively achieved, which is conducive to saving preparation costs.

[0061] Specifically, Figure 1As shown, the patterned bonding layer 200 also includes a second bonding area 202 isolated from the structural bonding area 203, and the second bonding area 202 is located on the second interconnect structure 502, so that the second interconnect structure 502 is electrically connected to the bonding substrate 300 through the second bonding area 202, wherein the second interconnect structure 502 is isolated from the first substrate layer 101, then in some optional embodiments, the second bonding area 202 may not be isolated from the structural bonding area 203, that is, the second bonding area 202 and the structural bonding area 203 can be used to electrically connect to the second interconnect structure 502 (and the second functional area 302), increase the area of ​​the electrical connection area, and improve the stability and reliability of the electrical connection; in other optional embodiments, the structural bonding area 203 also includes at least two bonding sub-areas, wherein at least one bonding sub-area is connected to the second bonding area 202, to Another bonding sub-area is electrically isolated from the second bonding area 202 (for example, separated by a target isolation groove), which can not only maintain a larger area of ​​bonding material for realizing structural bonding, but also increase the area of ​​the electrical connection region with the second interconnect structure 502, thereby improving the reliability of electrical connection; in some preferred embodiments, the second bonding area 202 and the structural bonding area 203 are isolated from each other, and the two can be isolated from each other by a vacuum bonding cavity 204, or a target isolation groove can be opened on the peripheral side of the second bonding area 202, and the target isolation groove is surrounded by the second bonding area 202, so that the second bonding area 202 is isolated from the structural bonding area 203, thereby improving the accuracy of electrical connection and reducing loss. At the same time, the area of ​​the second bonding area 202 can be larger, increasing the bonding area and bonding stability, which is beneficial to improving the bonding structure used for MEMS micromirrors and the efficiency and performance of MEMS micromirrors.

[0062] Specifically, in some exemplary embodiments, the surface of the patterned bonding layer 200 is flush; that is, on the contact surface between the patterned bonding layer 200 and the SOI substrate 100 and the metal interconnect structure 500, the surfaces of the first bonding area 201, the second bonding area 202 and the structural bonding area 203 close to the SOI substrate 100 are flush with each other; and on the gold-silicon bonding surface between the patterned bonding layer 200 and the bonding substrate 300, the surfaces of the gold-silicon bonding surfaces of the first bonding area 201, the second bonding area 202 and the structural bonding area 203 are also flush with each other, which can improve the surface flatness of the patterned bonding layer 200, is beneficial to improving the bonding strength and bonding stability, and further helps to improve the preparation yield and performance of the bonding structure and MEMS micromirror.

[0063] Specifically, Figure 2As shown, in some exemplary embodiments, the patterned bonding layer 200 also includes a cutting groove area 205, which is located on the peripheral side of the structural bonding area 203, and can reserve a certain cutting space. In subsequent packaging and other processes, it is used to cut the bonding structure of the array-type package for the MEMS micromirror into multiple chip units as a whole, so as to finally form a MEMS micromirror, thereby avoiding damage to the functional layer and other structures therein in subsequent processes, and also avoiding the metal material of the patterned bonding layer 200 blocking the laser during the cutting process, which is beneficial to improving the preparation yield and structural reliability of the chip units and MEMS micromirrors; in some exemplary embodiments, the lateral size of the cutting groove area 205 is 40μm~80μm, and the lateral size can be any point value between 40μm~80μm, which is not enumerated here.

[0064] Specifically, the material of the patterned bonding layer 200 includes metal; the metal material of the patterned bonding layer 200 includes gold, and the gold layer has high conductivity, which can improve the effectiveness of current transmission, reduce resistance, improve the performance and efficiency of the bonding structure for MEMS micromirrors and MEMS micromirrors, and has high stability, which is beneficial to their long-term performance; and the gold layer has good wettability and adhesion, which can greatly improve the bonding strength between the patterned bonding layer 200 and the dielectric layer 103 (and the metal interconnect structure 500) on the surface of the first substrate layer 101, and can also greatly improve the bonding strength between the patterned bonding layer 200 and the bonding substrate 300, thereby improving the overall bonding strength and structural reliability of the bonding structure for MEMS micromirrors, which is beneficial to improving the long-term performance of the subsequently manufactured MEMS micromirrors.

[0065] Specifically, the longitudinal dimension of the patterned bonding layer 200 is 500nm to 600nm; it can be understood that the longitudinal dimension of the patterned bonding layer 200 can be any point value between 500nm and 600nm; illustratively, the longitudinal dimension of the patterned bonding layer 200 can be 500nm, 520nm, 525nm, 530nm, 550nm, 560nm, 580nm, 600nm, etc.; in this way, it is possible to achieve effective bonding between the patterned bonding layer 200 and the bonding substrate 300 through the gold-silicon bonding process, thereby improving the bonding strength and the stability of the overall structure, and avoiding adverse effects on the performance of the bonding structure used for the MEMS micromirror.

[0066] Specifically, the bonding substrate 300 is located on a surface of the patterned bonding layer 200 facing away from the SOI substrate 100, and the bonding substrate 300 has an isolation region 301 and a second functional region 302, the second functional region 302 is used to form the upper comb teeth of the MEMS micromirror, and the second functional region 302 and the first functional region 1010 are electrically isolated in the vertical direction by the patterned bonding layer 200, wherein the isolation region 301 is electrically connected to the first interconnection structure 501 through the first bonding region 201, and the isolation region 301 and the second functional region 302 are isolated from each other to avoid the first interconnection structure 501 electrically connected to the first substrate layer 101 and the second functional region 302 of the bonding substrate 300. Abnormal interference is generated between the second functional area 302, thereby improving the isolation reliability of the second functional area 302 and the first substrate layer 101; the second functional area 302 is electrically connected to the second interconnect structure 502 through the second bonding area 202, and the second functional area 302 can form upper comb teeth in the subsequent process, while the first functional area 1010 can form lower comb teeth. The first functional area 1010 and the second functional area 302 cooperate with each other to effectively drive the upper comb teeth to vibrate under the action of electrostatic force through the second interconnect structure 502, thereby realizing the rotation function of the mirror surface in the MEMS micromirror, and effectively avoiding interference between the upper comb teeth and the lower comb teeth, thereby improving the device stability and reliability of the MEMS micromirror.

[0067] Specifically, the isolation groove structure 400 vertically penetrates the patterned bonding layer 200 and the bonding substrate 300, so that the first bonding area 201 is independent of the structural bonding area 203, and the isolation area 301 is independent of the second functional area 302 of the bonding substrate 300, thereby improving the effectiveness of electrical isolation; and, the isolation groove structure 400 can be formed by etching the patterned bonding layer 200 and the bonding substrate 300 once during the preparation process, which greatly saves preparation time. The isolation groove structure 400 is convenient and quick to open, which is conducive to saving preparation costs.

[0068] like Figure 1 As shown, the isolation groove structure 400 exposes the dielectric layer 103 on the peripheral side of at least part of the metal interconnection structures 500 among the multiple metal interconnection structures 500, that is, the isolation groove structure 400 is located on the peripheral side of at least part of the metal interconnection structures 500 among the multiple metal interconnection structures 500, and the dielectric layer 103 exposed by the isolation groove structure 400 is the dielectric layer 103 on the surface of the SOI substrate 100, so as to isolate the metal interconnection structure 500 separately; further, the isolation groove structure 400 is located on the peripheral side of the first interconnection structure 501, so as to expose the dielectric layer 103 on the peripheral side of the first interconnection structure 501 and located on the surface of the first substrate layer 101, so as to improve the isolation effectiveness.

[0069] Specifically, Figure 1As shown, the contact window 120 is located in the projection area of ​​the inner side wall of the isolation groove structure 400, that is, the isolation groove structure 400 is opened on the peripheral side of the contact window 120. In this way, the lateral dimension of the inner side wall of the isolation groove structure 400 is larger than the lateral dimension of the contact window 120, that is, larger than the maximum lateral dimension of the end of the first interconnect structure 501, which can effectively ensure that the first interconnect structure 501 is completely isolated from the structural bonding area 203 of the metal bonding layer, and the isolation reliability is good; in addition, there can also be a partial structural bonding area 203 on the peripheral side of the isolation groove structure 400 to provide a certain support force for the bonding substrate 300 on the peripheral side of the isolation groove, which is beneficial to improve the overall structural strength of the bonding structure for the MEMS micromirror.

[0070] The bonding structure for the MEMS micromirror realizes the electrical isolation of the first functional area 1010 in the SOI substrate 100 and the second functional area 302 in the bonding substrate 300 through a special bonding structure, and the bonding structure and the upper and lower surfaces of the finally formed MEMS micromirror device can be simultaneously connected through multiple metal interconnect structures 500, and the electrical connection reliability and electrical isolation effectiveness of each region in different regions are effectively and accurately improved, which is beneficial to improving the electrical performance of the MEMS micromirror.

[0071] The following combination Figure 3-6 The method for forming a bonding structure for a MEMS micromirror according to an embodiment of the present application is described in detail.

[0072] like Figure 3 As shown, before forming the patterned bonding layer 200 on the SOI substrate 100 , first, the SOI substrate 100 having a plurality of through holes 110 is provided.

[0073] The SOI substrate 100 comprises a first substrate layer 101 and a second substrate layer 102, the materials of the first substrate layer 101 and the second substrate layer 102 are silicon materials, and the SOI substrate 100 has its own dielectric layer 103, the material of the dielectric layer 103 is silicon oxide, which can effectively isolate the first substrate layer 101 and the second substrate layer 102, so that the isolation effect inside the SOI substrate 100 is good, which is beneficial to reduce unexpected interference in subsequent processes, and improve the bonding structure used for MEMS micromirrors and the preparation yield and performance of MEMS micromirrors.

[0074] In addition, the inner walls of the through holes 110 in the SOI substrate 100 are also covered with a dielectric layer 103. After the through holes 110 are formed, the SOI substrate 100 can be thermally oxidized to thermally oxidize the exposed surface of the through holes 110 to form a thermal oxidation layer, i.e., the dielectric layer 103. The through holes 110 are used to fill the metal interconnect structure 500 in subsequent steps. The dielectric layer 103 on the inner wall of the through holes 110 can effectively isolate the metal interconnect structure 500 from the silicon material in the SOI substrate 100, thereby greatly improving the isolation reliability and the reliability of the overall structure.

[0075] Then, if Figure 4 As shown, the SOI substrate 100 having a plurality of through-holes 110 is etched to form contact windows 120 at ends of at least some of the through-holes 110 among the plurality of through-holes 110 .

[0076] In this step, the contact window 120 penetrates the dielectric layer 103 at the end of the through hole 110, and the contact window 120 is formed on the through hole 110 for filling the first interconnect structure 501, so that after the first interconnect structure 501 is subsequently filled, the first interconnect structure 501 can be electrically connected to the first functional area 1010, thereby improving the accuracy and reliability of the electrical connection; at the same time, the integrity of the dielectric layer 103 at the through hole 110 for filling the second interconnect structure 502 is maintained to effectively isolate the second interconnect structure 502 from the SOI substrate 100.

[0077] It should be noted that, during the etching process, the surface roughness of the contact window 120 is improved to a certain extent, which is beneficial to the bonding reliability between the subsequently formed first interconnect structure 501 (or seed layer) and the silicon material of the first functional area 1010, and is beneficial to improving the conductivity between the first functional area 1010 and the first interconnect structure 501 in the first substrate layer 101; in some preferred embodiments, the contact window 120 is a funnel-shaped structure, and accordingly, the end of the first interconnect structure 501 filled in the subsequent steps is also a funnel-shaped structure, which can increase the contact area between the seed layer and the first functional area 1010, and is further beneficial to improving the bonding strength and conductivity.

[0078] Then, if Figure 5 As shown, a plurality of metal interconnect structures 500 are formed in the SOI substrate 100 having the contact windows 120 formed therein.

[0079] In this step, a seed layer can be first formed in the through hole 110 by double-sided magnetron sputtering, and then a metal material can be filled by electroplating. The seed layer includes a titanium / copper seed layer, and the metal material of the metal interconnect structure 500 includes copper metal; wherein the chemical properties of titanium metal are stable, and it can effectively protect the inner wall of the through hole 110, and titanium metal has good adhesion and conductivity, and can improve the quality and stability of the seed layer and the metal interconnect structure 500; and the copper seed layer can provide conductivity, which is conducive to the subsequent electroplating of metal materials to be carried out stably and effectively; thereafter, the filled gold The metal material protrudes from the surface of the dielectric layer 103 on the first substrate layer 101, and the filled metal material can be flattened. The flattening can be performed by surface grinding using a chemical mechanical polishing (CMP) process until the surface of the plurality of metal interconnect structures 500 is flush with the dielectric layer 103 on the surface of the first substrate layer 101, which is beneficial to improving the flatness of each layer structure formed subsequently, and improving the morphology accuracy and structural reliability of the bonding structure for the MEMS micromirror and the MEMS overall structure; then, vacuum heat treatment is performed at 350°C to 500°C to form the metal interconnect structure.

[0080] The first interconnect structure 501 and the second interconnect structure 502 are formed simultaneously in this step. The first interconnect structure 501 is formed in the through hole 110 having the contact window 120 , and the second interconnect structure 502 is formed in the through hole 110 without the contact window 120 .

[0081] It can be understood that the temperature of vacuum heat treatment can be any point value between 350℃ and 500℃; illustratively, the temperature can be 350℃, 375℃, 400℃, 425℃, 450℃, 475℃, 500℃, etc.; in this way, vacuum heat treatment can effectively reduce the stress of metal material (i.e., copper) and improve the reliability of metal interconnect structure 500.

[0082] Then, if Figure 6 As shown, a step of forming a patterned bonding layer 200 on the SOI substrate 100 is performed.

[0083] The first bonding area 201, the second bonding area 202 and the structural bonding area 203 in the patterned bonding layer 200 are formed simultaneously in this step. In some exemplary embodiments, a whole layer of bonding material can be deposited on the SOI substrate 100, and then a hard mask is used to form the patterned bonding layer 200 on the SOI substrate 100 by photolithography. The patterning accuracy is high, which is beneficial to improving the effectiveness and reliability of electrical connection or electrical isolation between various structures in the bonding structure used for MEMS micromirrors.

[0084] Next, the surface of the SOI substrate 100 having the patterned bonding layer 200 is bonded to the bonding substrate 300 to obtain a bonding structure. The material of the patterned bonding layer 200 is a gold material, which can form a gold-silicon bonding surface, greatly improving the bonding strength; at the same time, the structural bonding and electrical connection can be realized simultaneously in this step. On the one hand, the structural bonding area 203 can realize a large-area bonding connection with the bonding substrate 300, thereby improving the bonding reliability. On the other hand, the isolation area 301 in the bonding substrate 300 contacts the first bonding area 201 of the patterned bonding layer 200, thereby realizing the electrical connection between the isolation area 301, the first bonding area 201 and the first interconnect structure 501. , the second functional area 302 in the bonding substrate 300 contacts the second bonding area 202 of the patterned bonding layer 200 to achieve electrical connection among the second functional area 302, the second bonding area 202 and the second interconnection structure 502; and the first interconnection structure 501 and the second interconnection structure 502 have been formed in the previous step, and the shape of the patterned bonding layer 200 has also been determined, which is conducive to improving the fault tolerance of the bonding step. Even if there is an alignment deviation between the SOI substrate 100 and the bonding substrate 300 during the bonding process, it will not affect the electrical performance of the first interconnection structure 501 and the second interconnection structure 502 after bonding, which is also conducive to reducing the difficulty of preparation and improving the preparation yield.

[0085] In addition, the bonding area corresponding to the gold-silicon bonding surface of the bonding substrate 300 has the same shape as the patterned bonding layer 200, that is, the gold-silicon bonding surface and the first interconnection structure 501 are structurally spaced by the layer structure of the first bonding area 201 (but the electrical connection between the two is not affected), so that the first interconnection structure 501 is not affected by the stress during the bonding process, thereby improving the morphology accuracy and performance of the bonding structure for the MEMS micromirror; similarly, the gold-silicon bonding surface and the second interconnection structure 502 are structurally spaced by the layer structure of the second bonding area 202 (but the electrical connection between the two is not affected), so that the second interconnection structure 502 is not affected by the stress during the bonding process.

[0086] It should be noted that, in the formation method, in the electrical connection area formed by the multilayer structure, the layer structures located in the same layer can be formed at the same height and synchronously formed in the same process step; illustratively, the first interconnection structure 501, the first bonding area 201 and the isolation area 301 form an electrical connection area for conducting the first functional area 1010, and the second interconnection structure 502, the second bonding area 202 and the second functional area 302 form an electrical connection area for conducting the second functional area 302, wherein the surfaces of the first interconnection structure 501 and the second interconnection structure 502 can be formed at the same height and in the same process, that is, in the process of forming the metal interconnection structure 500 In the embodiment, the first interconnect structure 501 and the second interconnect structure 502 having the same height are formed synchronously by filling different through holes 110, which is beneficial to improving the surface flatness and the bonding quality in the subsequent steps; the first bonding area 201 and the second bonding area 202 are located at the same height and can be formed synchronously in the process of forming the patterned bonding layer 200; the isolation area 301 and the second functional area 302 belong to the structure of the bonding substrate 300, can be kept at the same thickness and height during the bonding process, and are formed synchronously in the bonding process, so that the height consistency of each layer of the bonding structure for the MEMS micromirror is good, which is beneficial to improving the preparation yield and performance of the MEMS micromirror.

[0087] Next, the bonding structure is etched to form an isolation groove structure 400 , thereby obtaining a bonding structure for a MEMS micromirror.

[0088] In this step, etching is performed on the area where the first interconnect structure 501 is located to etch away the graphic bonding layer 200 and the bonding substrate 300 on the side of the first interconnect structure 501, and the graphic bonding layer 200 and the bonding substrate 300 are penetrated at one time, so as to effectively isolate the first bonding area 201 and the structural bonding area 203, and isolate the isolation area 301 and the second functional area 302 of the bonding substrate 300, with high preparation accuracy, fast preparation efficiency and good isolation effect.

[0089] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0090] What is described above are only some embodiments of the present application and are not intended to limit the present application. Those skilled in the art should understand that the present application may undergo various changes and improvements, and any modifications, equivalent substitutions and improvements made in accordance with the present application shall fall within the scope of protection required by the present application.

Claims

1. A bonding structure for a MEMS micromirror, characterized in that: It comprises an SOI substrate, a patterned bonding layer, a bonding substrate and an isolation groove structure, wherein the patterned bonding layer is located between the SOI substrate and the bonding substrate; The SOI substrate includes a first functional area for forming lower comb teeth of a MEMS micromirror, and the bonding substrate includes a second functional area for forming upper comb teeth of a MEMS micromirror, and the first functional area and the second functional area are electrically isolated in a vertical direction by the patterned bonding layer; The SOI substrate has a plurality of metal interconnect structures running vertically therethrough, and a dielectric layer is provided between the metal interconnect structures and the SOI substrate; At least a portion of the patterned bonding layer is located on the metal interconnect structure, and the metal interconnect structure is electrically connected to the bonding substrate through the patterned bonding layer; The isolation trench structure vertically penetrates the patterned bonding layer and the bonding substrate, and exposes the dielectric layer on the peripheral side of at least a portion of the metal interconnection structures among the plurality of metal interconnection structures.

2. The bonding structure for a MEMS micromirror according to claim 1, characterized in that: The multiple metal interconnect structures include a first interconnect structure, a contact window penetrating the dielectric layer is opened on the surface of the SOI substrate, and an end of the first interconnect structure is located in the contact window, so that the first interconnect structure is electrically connected to the first functional area in the SOI substrate through the contact window.

3. The bonding structure for a MEMS micromirror according to claim 2, characterized in that: The SOI substrate comprises a first substrate layer and a second substrate layer, the thickness of the first substrate layer is smaller than that of the second substrate layer, the first functional area is located in the first substrate layer, and the contact window is located on a side surface of the first substrate layer away from the second substrate layer.

4. The bonding structure for a MEMS micromirror according to claim 2, characterized in that: A lateral dimension of an end of the contact window close to the bonding substrate is larger than a lateral dimension of an end of the contact window far from the bonding substrate.

5. The bonding structure for a MEMS micromirror according to claim 2, characterized in that: The contact window is located in a projection area of ​​an inner side wall of the isolation trench structure.

6. The bonding structure for a MEMS micromirror according to claim 2, characterized in that: The patterned bonding layer includes a first bonding area, and the bonding substrate includes an isolation area. The first bonding area and the isolation area are both located on the first interconnection structure, and the isolation groove structure is surrounded by the first bonding area and the isolation area so that the first bonding area is isolated from the structural bonding area of ​​the patterned bonding layer, and the isolation area is isolated from the bonding substrate.

7. The bonding structure for a MEMS micromirror according to any one of claims 1 to 6, characterized in that: The plurality of metal interconnect structures include a second interconnect structure, and the second interconnect structure and the first functional area in the SOI substrate are isolated from each other by the dielectric layer.

8. The bonding structure for a MEMS micromirror according to claim 7, characterized in that: The plurality of metal interconnect structures include a first interconnect structure, the first interconnect structure is electrically connected to a first functional region in the SOI substrate, and the second interconnect structure is flush with a surface of the first interconnect structure.

9. The bonding structure for a MEMS micromirror according to claim 7, characterized in that: The patterned bonding layer also includes a second bonding area isolated from the structural bonding area of ​​the patterned bonding layer, and the second bonding area is located on a second interconnection structure of the multiple metal interconnection structures, so that the second interconnection structure is electrically connected to the second functional area of ​​the bonding substrate through the second bonding area.

10. The bonding structure for a MEMS micromirror according to any one of claims 1 to 6, characterized in that: The patterned bonding layer comprises a structural bonding area and a vacuum bonding cavity, the structural bonding area is a closed surface, and the vacuum bonding cavity is located between the SOI substrate, the structural bonding area and the bonding substrate.

11. The bonding structure for a MEMS micromirror according to any one of claims 1 to 6, characterized in that: The patterned bonding layer satisfies at least one of the following characteristics: The material of the patterned bonding layer includes metal; The longitudinal dimension of the patterned bonding layer is 500nm-600nm.

12. A method for forming a bonding structure for a MEMS micromirror, characterized in that: include: forming a patterned bonding layer on the SOI substrate; The SOI substrate has a plurality of metal interconnect structures running vertically therethrough, a dielectric layer is provided between the metal interconnect structures and the SOI substrate, and at least a portion of the patterned bonding layer is located on the metal interconnect structures; The surface of the SOI substrate having the patterned bonding layer is bonded to a bonding substrate to obtain a bonding structure; the metal interconnection structure is electrically connected to the bonding substrate through the patterned bonding layer; the SOI substrate includes a first functional area for forming the lower comb teeth of the MEMS micromirror, and the bonding substrate includes a second functional area for forming the upper comb teeth of the MEMS micromirror, and the first functional area and the second functional area are electrically isolated in the vertical direction by the patterned bonding layer; The bonding structure is etched to form an isolation groove structure to obtain a bonding structure for a MEMS micromirror; the isolation groove structure vertically penetrates the patterned bonding layer and the bonding substrate and exposes the dielectric layer on the peripheral side of at least part of the metal interconnection structures among the multiple metal interconnection structures.

13. The method for forming a bonding structure for a MEMS micromirror according to claim 12, characterized in that: Before forming a patterned bonding layer on the SOI substrate, the method further includes: Etching an SOI substrate having a plurality of through holes to form contact windows at ends of at least some of the through holes; the contact windows penetrate the dielectric layer at the ends of the through holes; A plurality of metal interconnect structures are formed in an SOI substrate having a contact window formed therein; the metal interconnect structures are filled in through holes, and the plurality of metal interconnect structures include a first interconnect structure, and the first interconnect structure is electrically connected to a first functional area in the SOI substrate through the contact window.

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