A MEMS device, a preparation method thereof and an electronic device

Abstract

The application provides a MEMS device and a preparation method thereof and an electronic device. The method comprises the following steps: providing a substrate, wherein the substrate comprises a sensitive film layer, at least one pressure-sensitive resistor is arranged in the sensitive film layer, a structure support layer is arranged on the sensitive film layer, a reference pressure cavity is formed in the structure support layer, and a through hole penetrating through the structure support layer is formed outside the reference pressure cavity; a rewiring layer is formed on the side wall and the bottom of the through hole and the surface of the structure support layer, wherein the rewiring layer is electrically connected with the at least one pressure-sensitive resistor; a dry film layer is covered on at least part of the surface of the rewiring layer, the dry film layer is attached with the rewiring layer on the side wall of the through hole, and an isolation cavity is formed between the dry film layer and the rewiring layer at the bottom of the through hole. The method of the application can form the dry film layer as a protective layer of the rewiring layer, thereby protecting the metal inside the through silicon via and avoiding damage to the metal inside the through silicon via.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a MEMS device, a preparation method thereof and an electronic device. BACKGROUND

[0002] The MEMS pressure sensor is a frontier research field developed on the basis of the MEMS process and is widely applied in the fields of electronics, industry and the like.

[0003] Among them, the absolute pressure sensor is a kind of MEMS pressure sensor, such as Figure 1 As shown in the figure, a reference pressure cavity 103 and a through hole 104 are formed in a structure support layer 100, a redistribution layer 101 is formed inside the through hole 104 and on the surface of the structure support layer 100, and the redistribution layer 101 is provided with a metal circuit, when subjected to pressure, the resistance of the pressure-sensitive resistor 106 in the sensitive membrane layer 105 will change, thereby converting the pressure signal into an electrical signal.

[0004] In the traditional process, a polyimide layer 102 is usually used as a protective layer of the redistribution layer 101, but this structure cannot protect the metal inside the through hole 104, which leads to the long-term exposure of the metal inside the through hole 104 and is prone to oxidation and corrosion, and reduces the oxidation resistance and corrosion resistance. SUMMARY

[0005] A series of simplified concepts are introduced in the summary part, which will be further described in detail in the specific embodiment part. The summary part of the present application does not mean to try to limit the key features and necessary technical features of the claimed technical solution, and does not mean to try to determine the protection scope of the claimed technical solution.

[0006] In view of the existing problems, the present application provides a preparation method of a MEMS device, comprising:

[0007] A substrate is provided, the substrate comprises a sensitive membrane layer, at least one pressure-sensitive resistor is arranged in the sensitive membrane layer, a structure support layer is arranged on the sensitive membrane layer, a reference pressure cavity is formed in the structure support layer, and a through hole penetrating through the structure support layer is formed outside the reference pressure cavity;

[0008] A redistribution layer is formed on the side wall and bottom of the through hole and the surface of the structure support layer, wherein the redistribution layer is electrically connected to at least one pressure-sensitive resistor;

[0009] A dry film layer is covered on at least part of the surface of the redistribution layer, the dry film layer is attached to the redistribution layer on the side wall of the through hole, and an isolation cavity is formed between the dry film layer and the redistribution layer at the bottom of the through hole.

[0010] Exemplarily, the substrate further comprises a base layer and an insulating layer on the base layer, a cavity penetrating through the base layer is arranged in the base layer, and the sensitive film layer is on the insulating layer.

[0011] Exemplarily, a dielectric layer is formed on the sensitive film layer, and a side of the structure support layer on which the reference pressure cavity is formed is bonded with the dielectric layer.

[0012] Exemplarily, the dielectric layer comprises a first dielectric layer and a second dielectric layer, a conductive contact hole is further arranged in the first dielectric layer, pads are arranged on the first dielectric layer, and the second dielectric layer covers the first dielectric layer and part of the surface of the pads, each pad is electrically connected to a corresponding pressure sensitive resistor through the conductive contact hole, and each rewiring layer is electrically connected to one pad.

[0013] Exemplarily, the method for forming the rewiring layer comprises:

[0014] depositing a seed layer on the bottom and sidewall of the through hole;

[0015] forming the rewiring layer on the seed layer by electroplating.

[0016] Exemplarily, before forming the rewiring layer, the method further comprises:

[0017] forming a diffusion barrier layer on the sidewall of the through hole and the surface of the structure support layer.

[0018] Exemplarily, the dry film layer covering at least part of the surface of the rewiring layer comprises:

[0019] pasting a dry film layer on at least part of the surface of the rewiring layer by a vacuum film pasting machine;

[0020] baking the dry film layer.

[0021] Exemplarily, the reference pressure cavity is a vacuum cavity.

[0022] Another aspect of the present application provides a MEMS device, comprising:

[0023] a substrate, the substrate comprising a sensitive film layer, at least one pressure sensitive resistor arranged in the sensitive film layer;

[0024] a structure support layer on the sensitive film layer, a reference pressure cavity and a through hole penetrating through the structure support layer formed in the structure support layer;

[0025] a rewiring layer covering the sidewall and bottom of the through hole and part of the surface of the structure support layer, wherein the rewiring layer is electrically connected to at least one pressure sensitive resistor.

[0026] a dry film layer covering at least part of the surface of the re-wiring layer, the dry film layer being attached to the side wall of the through hole and a separation cavity being formed between the dry film layer and the re-wiring layer at the bottom of the through hole.

[0027] Exemplarily, further comprising:

[0028] the substrate further comprises a base layer and an insulating layer on the base layer, a cavity penetrating through the base layer is provided in the base layer, and the sensitive film layer is on the insulating layer.

[0029] Exemplarily, further comprising:

[0030] a dielectric layer on the sensitive film layer, the dielectric layer comprising a first dielectric layer and a second dielectric layer;

[0031] a diffusion barrier layer covering the side wall of the through hole and the surface of the structural support layer;

[0032] a pad on the first dielectric layer, part of the surface of the pad being covered by the second dielectric layer, and the upper surface of the pad being in contact with the re-wiring layer;

[0033] a conductive contact hole in the first dielectric layer, each pad being electrically connected to a corresponding piezoresistor through the conductive contact hole.

[0034] Exemplarily, the separation cavity is a vacuum cavity.

[0035] Exemplarily, the reference pressure cavity is a vacuum cavity.

[0036] In still another aspect, the present application provides an electronic device comprising the MEMS device as described above.

[0037] The MEMS device and the preparation method thereof according to the embodiments of the present application, by using a dry film layer as a protective layer of the re-wiring layer, the dry film layer being attached to the side wall of the through hole and a separation cavity being left at the bottom of the through hole, the re-wiring layer inside the through hole is protected, avoiding the oxidation and corrosion of the re-wiring layer inside the through hole, and at the same time, due to the existence of the separation cavity, the shrinkage force of the dry film layer during the treatment (such as baking) of the dry film layer can be avoided to cause tearing force to the bottom metal, thereby avoiding the damage of the re-wiring layer at the bottom of the through hole. BRIEF DESCRIPTION OF DRAWINGS

[0038] The following drawings for the present application are hereby included as part of the present application to facilitate the understanding of the present application. The embodiments of the present application and its description are shown in the drawings to explain the principles of the present application.

[0039] In the drawings:

[0040] Figure 1 A cross-sectional view of a device obtained by a method of fabricating a MEMS device according to an embodiment of the present application is shown;

[0041] Figure 2 A flow chart of a method of fabricating a MEMS device according to an embodiment of the present application is shown;

[0042] Figure 3 A cross-sectional view of a device obtained by a method of fabricating a MEMS device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0043] The present application will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the application are shown. This application may, however, be embodied in different forms, and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions are exaggerated for clarity. Like reference numerals refer to like elements throughout.

[0044] It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0045] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, then a dependent element or feature described as "below" or "beneath" another element or feature is oriented "above" or "over" the other element or feature. Thus, the exemplary term "below" or "beneath" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] Embodiments of the application are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the application. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments of the application should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle will, typically, have rounded or curved features and / or a gradient of implant concentration at its edges rather than a binary change between implanted and non-implanted regions. Similarly, an implanted region illustrated as a rectangle will, typically, have a region of some implant between the implanted region and the surface upon which the implant was performed. Thus, the regions illustrated in the figures are schematic and are not intended to illustrate actual dimensions but are intended to be exemplary of the regions that are formed during the fabrication of a device. As used herein, the term "substantially" is used to describe an aspect that is expected to be identical to a true value within a margin of error. Further, the term "substantially" is used to describe an aspect that is not identical to a true value, but is sufficiently similar as to have little to no effect on the results obtained from a process, measurement, or test.

[0048] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and / or the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0049] In order to thoroughly understand the present application, detailed steps and structures will be presented in the following description in order to explain the technical solutions proposed by the present application. The preferred embodiments of the present application are described in detail as follows, however, the present application can have other embodiments in addition to these detailed descriptions.

[0050] Therefore, in view of the existence of the foregoing technical problems, the present application proposes a preparation method of a MEMS device, as shown in Figure 2 which mainly comprises the following steps:

[0051] Step S1, providing a substrate, the substrate comprising a sensitive film layer, at least one piezoresistor being arranged in the sensitive film layer, a structure support layer being arranged on the sensitive film layer, a reference pressure cavity being formed in the structure support layer, a through hole being formed outside the reference pressure cavity and penetrating the structure support layer;

[0052] Step S2, forming a redistribution layer on the side wall and bottom of the through hole and the surface of the structure support layer, wherein the redistribution layer is electrically connected to at least one piezoresistor;

[0053] Step S3, covering a dry film layer on at least part of the surface of the redistribution layer, the dry film layer being attached to the redistribution layer on the side wall of the through hole and an isolation cavity being formed between the dry film layer and the redistribution layer at the bottom of the through hole.

[0054] The MEMS device and the preparation method thereof according to the embodiments of the present application, by using a dry film as a protective layer of the redistribution layer, the dry film layer being attached to the side wall of the through hole and an isolation cavity being left at the bottom of the through hole, the redistribution layer inside the through hole is protected, avoiding the oxidation and corrosion of the redistribution layer inside the through hole, at the same time, due to the existence of the isolation cavity, the tearing force caused by the shrinkage of the dry film layer during the treatment (such as baking) of the dry film layer to the bottom metal can be avoided, and further, the damage of the redistribution layer at the bottom of the through hole can be avoided.

[0055] Embodiment one

[0056] Next, the preparation method of the MEMS device according to the present application will be described in detail, wherein, Figures 2 to 3 the preparation method of the MEMS device according to the present application will be described in detail, wherein, Figure 2 a flow chart of the manufacturing method of the MEMS device according to one specific embodiment of the present application is shown; Figure 3 a cross-sectional schematic diagram of the device obtained by the preparation method of the MEMS device according to one specific embodiment of the present application is shown.

[0057] Exemplarily, as shown in Figure 2 the preparation method of the MEMS device according to the present application comprises the following steps:

[0058] First, a step S1 is performed to provide a substrate including a sensitive film layer in which at least one piezoresistor is disposed, and a structural support layer disposed on the sensitive film layer and having a reference pressure cavity formed therein, and a through hole formed in the structural support layer outside the reference pressure cavity.

[0059] The MEMS device can be any suitable device known to those skilled in the art, and in this embodiment, the technical solutions of the present application are explained and described mainly in the case where the MEMS device is a MEMS absolute pressure sensor.

[0060] Specifically, in one example, as shown in Figure 3 The substrate is a silicon-on-insulator (SOI) substrate, which includes a base layer 300, an insulating layer 301 disposed on the base layer 300, and a sensitive film layer 302 disposed on the insulating layer 301. The base layer 300 can be made of at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs, or other III / V compound semiconductors. In other examples, the substrate can be a silicon-on- stacked silicon (SSOI) substrate, a silicon-on-stacked silicon germanium (S-SiGeOI) substrate, a silicon-on-germanium (SiGeOI) substrate, or a germanium-on-insulator (GeOI) substrate, etc., as long as it has a sensitive film layer thereon.

[0061] In one example, as shown in Figure 3 The first side of the substrate is etched to form a cavity 314 that penetrates the base layer 300.

[0062] In one example, as shown in Figure 3 The insulating layer 301 is a buried insulating layer of the SOI substrate, and the insulating layer 301 functions as an etching stop layer when the cavity 314 is formed. The insulating layer 301 can include any of a number of dielectric materials, non-limiting examples of which include oxides, nitrides, and oxynitrides, particularly oxides, nitrides, and oxynitrides of silicon. The insulating layer 301 can be formed using any of a number of methods, non-limiting examples of which include ion implantation methods, thermal or plasma oxidation or nitridation methods, chemical vapor deposition methods, and physical vapor deposition methods. The thickness of the buried insulating layer is typically 0.1 to 2 microns, but those skilled in the art can adjust it accordingly according to actual needs in this embodiment. In this embodiment, the insulating layer 301 is made of silicon dioxide.

[0063] In one example, as shown in Figure 3As shown, the sensitive film layer 302 is a silicon-based film layer. The thickness of the sensitive film layer affects linearity and sensitivity. Generally speaking, the thinner the sensitive film layer, the higher the sensitivity of pressure measurement. However, a thinner sensitive film layer will lead to greater film deflection, thereby reducing linearity. In this embodiment, those skilled in the art should understand that the thickness of the sensitive film layer 302 should be selected appropriately according to actual needs.

[0064] In one example, such as Figure 3 As shown, a varistor 311 is formed and a Wheatstone bridge connection is established by photolithography and ion implantation of the sensitive film layer 302. Those skilled in the art will recognize that the processes for forming the sensitive film layer and the varistor are very mature, so detailed processes will not be described here; however, conventional design and process parameters in the field can be consulted.

[0065] In one example, such as Figure 3 As shown, a first dielectric layer 303 is formed on the sensitive film layer 302. The first dielectric layer 303 is etched to form a contact hole. The contact hole penetrates the dielectric layer 303 and exposes the varistor. Metal is filled into the contact hole to form a conductive contact hole 312. The first dielectric layer 303 may include any of several dielectric materials, and non-limiting examples include oxides, nitrides, and oxide oxynitrides, especially oxides, nitrides, and oxide oxynitrides of silicon. In this embodiment, the first dielectric layer 303 may be silicon nitride.

[0066] In one example, such as Figure 3 As shown, pads 313 are provided on the first dielectric layer 303. These pads are electrically connected to the corresponding varistors via conductive contact holes and serve as input / output ports for the pressure sensor chip. Subsequently, a second dielectric layer 304 is deposited, covering the first dielectric layer 303 and the pads 313. The second dielectric layer 304 can be made of the same material as or a different material than the insulating layer 301. In this embodiment, the second dielectric layer 304 is made of silicon dioxide. Optionally, the pads 313 can be made of one or more metals such as aluminum, copper, gold, titanium, sodium, and platinum. In this embodiment, the pads 313 are made of aluminum. The second dielectric layer 304 is then planarized to obtain a flat surface, preparing for subsequent processes.

[0067] In one example, such as Figure 3As shown, the structural support layer 305 is a silicon layer. The method for forming a reference pressure cavity in the structural support layer includes etching the structural support layer 305 to form a reference pressure cavity 310. In this embodiment, the reference pressure cavity is a vacuum cavity. In some embodiments, the reference pressure cavity may also be a non-vacuum cavity with known pressure. Exemplarily, a bonding layer is deposited on the side of the structural support layer 305 where the reference pressure cavity 310 is formed. The bonding layer can be formed before or after the formation of the reference pressure cavity. The material of the bonding layer can be silicon oxide, nitride, or oxynitride.

[0068] Exemplarily, a bonding process is used to bond the side of the structural support layer 305 with the deposited bonding layer to the sensitive film layer 302 to form a single unit. More specifically, a bonding process is used to bond the side of the structural support layer 305 with the deposited bonding layer to the second dielectric layer 304 to form a single unit. In some embodiments, instead of depositing a bonding layer, the side of the structural support layer 305 with the reference pressure cavity 310 can be directly bonded to the second dielectric layer 304 to form a single unit. After bonding, the structural support layer 305 is located above the sensitive film layer 302. The bonding process can use one of the following: low-temperature electrostatic bonding, anodic bonding, etc. In an optional embodiment, after the bonding process, the structural support layer 305 can be thinned to increase heat dissipation, reduce the thickness of subsequent vias, and reduce the difficulty of subsequent via fabrication and filling.

[0069] In one example, such as Figure 3 As shown, the structural support layer 305 is etched to form a via 309, which penetrates the structural support layer 305. Subsequently, the second dielectric layer 304 is etched to expose a portion of the surface of the pad 313. In this embodiment, deep reactive ion etching (DRIE) can be used as the etching process. To prevent short circuits between devices and to provide protective isolation, a diffusion barrier layer 306 is deposited on the surface of the structural support layer 305 and the sidewalls of the via 309.

[0070] Subsequently, step S2 is performed to form a redistribution layer on the sidewalls and bottom of the through hole and on the surface of the structural support layer, wherein the redistribution layer is electrically connected to at least one of the varistors, for example, the bottom of the redistribution layer contacts the pad, thereby electrically connecting at least one of the varistors through the pad.

[0071] In one example, such as Figure 3 As shown, a redistribution layer 307 is formed on the sidewalls and bottom of the via 309 and on the surface of the structural support layer 305. The redistribution layer 307 is attached to the upper surface of the pad 313. The method for forming the redistribution layer 307 includes:

[0072] Seed layers are deposited on the bottom and sidewalls of through-hole 309;

[0073] The redistribution layer 307 is formed on the seed layer by electroplating.

[0074] In this embodiment, the seed layer is formed by electroplating or electroless plating. In some embodiments, the seed layer can be formed by physical vapor deposition or suitable techniques. It should be noted that the seed layer is a metal layer, which can include one or more metal layers. For example, the seed layer can include a first metal layer and a second metal layer on the first metal layer, the first metal layer can be a titanium layer, and the second metal layer can be a copper layer. In this embodiment, the seed layer can be a copper layer. In some embodiments, the seed layer can also be selected from other suitable metals. In this embodiment, the redistribution layer 307 can be multi-layered, and the multi-layered redistribution layer 307 can be formed by repeatedly adopting the electroplating process.

[0075] In one example, as shown in FIG. 3B, the redistribution layer 307 connects the through hole, the pad, and the internal wiring of the external circuit board, to achieve electrical connection between the MEMS absolute pressure sensor chip and the external circuit board. In this way, under the action of external pressure, the sensitive membrane layer 302 deforms, causing the piezoresistor 311 in the sensitive membrane layer 302 to deform. Due to the piezoresistive effect, the resistance of the piezoresistor 311 changes, and the change in the corresponding electrical signal is converted through the electrical connection, thereby measuring the pressure. Figure 3

[0076] Finally, step S3 is performed to cover the at least part of the surface of the redistribution layer with a dry film layer, the dry film layer is attached to the redistribution layer on the side wall of the through hole, and an isolation cavity is formed between the dry film layer and the redistribution layer at the bottom of the through hole. In one example, as shown in FIG. 3C, the dry film layer 308 is first attached to at least part of the surface of the redistribution layer 307 by a vacuum film press, and then the dry film layer 308 is attached to the redistribution layer 307 on the side wall of the through hole 309 by vacuum cavity vacuumization and heating, and an isolation cavity is formed between the dry film layer 308 and the redistribution layer 307 at the bottom of the through hole 309. In this embodiment, the isolation cavity is a vacuum cavity. In this embodiment, the temperature range of the vacuum molding process is 90 to 95 degrees Celsius. In this way, during the subsequent baking process, the compression force generated by the shrinkage of the dry film layer 308 will not cause tearing force to the metal at the bottom of the through hole 309, thereby avoiding damage to the metal at the bottom of the through hole 309. The composition of the dry film layer 308 includes one or more of melamine compounds, alkoxysiloxanes, and organic ammonium salts, but is not limited thereto. Figure 3

[0077] ​​This concludes the description of the key steps in the fabrication method of the MEMS device of the present invention. Other steps may also be included in the fabrication of a complete MEMS device, which will not be elaborated here.

[0078] In summary, the MEMS device fabrication method of the present invention uses a dry film layer as a protective layer for the redistribution layer. The dry film layer is attached to the sidewall of the through-silicon via and has an isolation cavity at the bottom of the through-silicon via, which protects the redistribution layer inside the through-silicon via and avoids oxidation and corrosion of the redistribution layer inside the through-silicon via. At the same time, due to the presence of the isolation cavity, the shrinkage force generated by the dry film layer during processing (e.g., baking) can be avoided to prevent tearing force on the bottom metal, thereby avoiding damage to the redistribution layer at the bottom of the through-silicon via.

[0079] Example 2

[0080] The present invention also provides a MEMS device, which is prepared by the method described in the first embodiment above.

[0081] Below, for reference Figure 3 The MEMS devices of the present invention will be explained and described, wherein structures identical to those in the foregoing Embodiment 1 will not be described in detail here.

[0082] Specifically, such as Figure 3 As shown, the MEMS device of the present invention includes:

[0083] A substrate, the substrate including a sensitive film layer 302, wherein at least one varistor 311 is disposed in the sensitive film layer 302;

[0084] A structural support layer 305 is located on the sensitive membrane layer 302, and a reference pressure cavity 310 and a through hole 309 are formed in the structural support layer 305.

[0085] A redistribution layer 307 covers the sidewalls and bottom of the via 309 and a portion of the surface of the structural support layer 305, wherein the redistribution layer is electrically connected to at least one of the varistors;

[0086] A dry film layer 308 covers at least a portion of the surface of the redistribution layer 307. The dry film layer 308 is attached to the sidewall of the via 309, and an isolation cavity is formed between the dry film layer 308 and the redistribution layer 307 at the bottom of the via 309.

[0087] Specifically, such as Figure 3As shown, the substrate is silicon-on-insulator (SOI), which includes a base layer 300, an insulating layer 301 on the base layer 300, and a sensitive film layer 302 on the insulating layer 301. The material of the base layer 300 can be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs, or other III / V compound semiconductors. In other examples, the substrate can be silicon-on-layered insulator (SSOI), silicon germanium-on-layered insulator (S-SiGeOI), silicon germanium-on-insulator (SiGeOI), germanium-on-insulator (GeOI), etc., as long as it has the sensitive film layer thereon. In this embodiment, the insulating layer 301 can be a silicon dioxide layer. In this embodiment, the sensitive film layer 302 can be a silicon-based film layer. In this embodiment, the structure support layer 305 can be a silicon layer. In this embodiment, the redistribution layer 307 is formed by electroplating based on a copper seed layer.

[0088] Further, the MEMS device of the present application further comprises:

[0089] a dielectric layer on the sensitive film layer 302, the dielectric layer including a first dielectric layer 303 and a second dielectric layer 304;

[0090] a diffusion barrier layer 306 covering the sidewalls of the via 309 and the surface of the structure support layer 305;

[0091] a pad 313, part of the surface of the pad 313 being covered by the second dielectric layer 304, the upper surface of the pad 313 being attached to the redistribution layer 307;

[0092] a conductive via 312 in the first dielectric layer 303, each pad being electrically connected to a corresponding piezoresistor through the conductive via.

[0093] In this embodiment, the second dielectric layer 304 can be made of the same material as the insulating layer 301 or a different material, and the second dielectric layer 304 can be, for example, a silicon dioxide layer. In this embodiment, the first dielectric layer 303 can be a silicon nitride layer. In this embodiment, the pad 313 can be made of aluminum.

[0094] The structure of the MEMS device of the present application has been introduced so far. The complete device can also include other component structures, which are not described here.

[0095] Since the MEMS device of the present application is formed with a dry film layer as a protective layer of the re-wiring layer, the dry film layer is attached to the side wall of the through silicon via and leaves a separation cavity at the bottom of the through silicon via, thereby protecting the re-wiring layer inside the through via from oxidation and corrosion. Meanwhile, since the separation cavity exists, the shrinkage force of the dry film layer during the treatment (such as baking) of the dry film layer can be avoided from causing tearing force to the bottom metal, thereby avoiding the damage of the re-wiring layer at the bottom of the through via.

[0096] Embodiment Three

[0097] In another embodiment of the present application, an electronic device is provided, which comprises the MEMS device of Embodiment Two. The MEMS device is the MEMS device of Embodiment Two, or the MEMS device obtained by the preparation method of Embodiment One.

[0098] The electronic device of the present embodiment can be a mobile phone, a tablet computer, a notebook computer, a netbook, a game console, a television, a VCD, a DVD, a navigator, a camera, a camcorder, a voice recorder, an MP3, an MP4, a PSP, or any other electronic product or device, or any intermediate product comprising the MEMS device. The electronic device of the present embodiment has better performance due to the use of the above-mentioned MEMS device.

[0099] Although a number of embodiments have been described herein, it is understood that the skilled person would be able to devise further modifications and embodiments which would fall within the ambit of the inventive concept disclosed. More particularly, various modifications and changes can be made within the scope of the present disclosure, the drawings, and the appended claims, in the arrangement and / or composition of parts of the subject matter. In addition to modifications and changes in the arrangement and / or composition of parts, the use of alternative materials for the parts is also a choice which would be apparent to the skilled person.

Claims

1. A method of fabricating a MEMS device, characterized by, The method comprises: providing a substrate comprising a sensitive film layer, at least one piezoresistor being arranged in the sensitive film layer, a structural support layer being arranged on the sensitive film layer, a reference pressure cavity being formed in the structural support layer, a through hole being formed outside the reference pressure cavity and penetrating the structural support layer; forming a redistribution layer on the side wall and bottom of the through hole and the surface of the structural support layer, wherein the redistribution layer is electrically connected to at least one piezoresistor; covering at least part of the surface of the redistribution layer with a dry film layer, the dry film layer being attached to the redistribution layer on the side wall of the through hole and an isolation cavity being formed between the dry film layer and the redistribution layer at the bottom of the through hole.

2. The method of claim 1, wherein, The substrate further comprises a base layer and an insulating layer arranged on the base layer, a cavity penetrating the base layer being arranged in the base layer, and the sensitive film layer being arranged on the insulating layer.

3. The method of claim 1, wherein, A dielectric layer is formed on the sensitive film layer, and the side of the structural support layer where the reference pressure cavity is formed is attached to the dielectric layer.

4. The method of claim 3, wherein, The dielectric layer comprises a first dielectric layer and a second dielectric layer, a conductive contact hole being further arranged in the first dielectric layer, a pad being arranged on the first dielectric layer, and the second dielectric layer covering part of the surface of the first dielectric layer and the pad, each pad being electrically connected to a corresponding piezoresistor through the conductive contact hole, and each redistribution layer being electrically connected to one pad.

5. The method of claim 1, wherein, The method for forming the redistribution layer comprises: depositing a seed layer on the bottom and side wall of the through hole; forming the redistribution layer on the seed layer by electroplating.

6. The method of claim 1, wherein, Before forming the redistribution layer, the method further comprises: forming a diffusion barrier layer on the side wall of the through hole and the surface of the structural support layer.

7. The method of claim 1, wherein, The covering of at least part of the surface of the redistribution layer with a dry film layer comprises: attaching a dry film layer to at least part of the surface of the redistribution layer by a vacuum laminator; baking the dry film layer.

8. The method of claim 1, wherein, The reference pressure cavity is a vacuum cavity.

9. A MEMS device, characterized by The MEMS device comprises: a substrate comprising a sensitive film layer, at least one piezoresistor being arranged in the sensitive film layer; a structural support layer arranged on the sensitive film layer, a reference pressure cavity and a through hole penetrating the structural support layer being formed in the structural support layer; a redistribution layer covering the side wall and bottom of the through hole and part of the surface of the structural support layer, wherein the redistribution layer is electrically connected to at least one piezoresistor; a dry film layer covering at least part of the surface of the redistribution layer, the dry film layer being attached to the side wall of the through hole and an isolation cavity being formed between the dry film layer and the redistribution layer at the bottom of the through hole.

10. The MEMS device of claim 9, wherein, The MEMS device further comprises: The substrate further comprises a base layer and an insulating layer arranged on the base layer, a cavity penetrating the base layer being arranged in the base layer, and the sensitive film layer being arranged on the insulating layer.

11. The MEMS device of claim 9, wherein, The MEMS device further comprises: a dielectric layer arranged on the sensitive film layer, the dielectric layer comprising a first dielectric layer and a second dielectric layer; a diffusion barrier layer covering the side wall of the through hole and the surface of the structural support layer; a pad on the first dielectric layer, a part of a surface of the pad being covered by the second dielectric layer, an upper surface of the pad being in contact with the redistribution layer; a conductive via in the first dielectric layer, each of the pads being electrically connected to a corresponding one of the varistors through the conductive via.

12. The MEMS device of claim 9, wherein, The isolation cavity is a vacuum cavity.

13. The MEMS device of claim 9, wherein, The reference pressure cavity is a vacuum cavity.

14. An electronic device, comprising: The electronic device comprises the MEMS device of one of claims 9 to 13.

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