CN116281835A - MEMS device, preparation method thereof and electronic device - Google Patents

Abstract

The invention provides an MEMS device, a preparation method thereof and an electronic device, wherein the method comprises the following steps: providing a substrate, wherein the substrate comprises a sensitive film layer, at least one piezoresistor is arranged in the sensitive film layer, a structural supporting layer is arranged on the sensitive film layer, a reference pressure cavity is formed in the structural supporting layer, and a through hole penetrating through the structural supporting layer is formed at the outer side of the reference pressure cavity; forming a rewiring layer on the side wall and the bottom of the through hole and the surface of the structural support layer, wherein the rewiring layer is electrically connected with at least one piezoresistor; and a dry film layer is covered on at least part of the surface of the rewiring layer, the dry film layer is attached to the rewiring layer positioned on the side wall of the through hole, and an isolation cavity is formed between the bottom dry film layer of the through hole and the rewiring layer. The method can form the dry film layer as the protective layer of the rewiring layer, so that the metal in the through silicon via is protected, and the damage of the metal in the through silicon via is avoided.

Description

MEMS device, preparation method thereof and electronic device

Technical Field

The invention relates to the technical field of semiconductors, in particular to an MEMS device, a preparation method thereof and an electronic device.

Background

MEMS pressure sensors are a leading-edge research field developed on the basis of MEMS technology and are widely applied to the fields of electronics, industry and the like.

As shown in fig. 1, a reference pressure cavity 103 and a through hole 104 are formed in a structural support layer 100, a rewiring layer 101 is formed inside the through hole 104 and on the surface of the structural support layer 100, a metal line is distributed in the rewiring layer 101, and when pressure is applied, the resistance value of a piezoresistor 106 in a sensitive film layer 105 changes, so that a pressure signal is converted into an electrical signal.

In the conventional process, the polyimide layer 102 is generally used as a protection layer of the re-wiring layer 101, but the structure cannot protect the metal inside the through hole 104, so that the metal inside the through hole 104 is exposed for a long time to be easily oxidized and corroded, and oxidation resistance and corrosion resistance are reduced.

Disclosure of Invention

In the summary, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description. The summary of the invention is not intended to define the key features and essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In view of the problems existing at present, one aspect of the present invention provides a method for manufacturing an MEMS device, including:

providing a substrate, wherein the substrate comprises a sensitive film layer, at least one piezoresistor is arranged in the sensitive film layer, a structural supporting layer is arranged on the sensitive film layer, a reference pressure cavity is formed in the structural supporting layer, and a through hole penetrating through the structural supporting layer is formed at the outer side of the reference pressure cavity;

forming a rewiring layer on the side wall and the bottom of the through hole and the surface of the structural support layer, wherein the rewiring layer is electrically connected with at least one piezoresistor;

and a dry film layer is covered on at least part of the surface of the rewiring layer, the dry film layer is attached to the rewiring layer positioned 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.

Illustratively, 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 arranged on the insulating layer.

Illustratively, a dielectric layer is formed on the sensitive membrane layer, and a side of the structural support layer on which the reference pressure chamber is formed is bonded to the dielectric layer.

The dielectric layer includes a first dielectric layer and a second dielectric layer, a conductive contact hole is further disposed in the first dielectric layer, a bonding pad is disposed on the first dielectric layer, the second dielectric layer covers a part of surfaces of the first dielectric layer and the bonding pad, each bonding pad is electrically connected to a corresponding varistor through the conductive contact hole, and each rewiring layer is electrically connected to one bonding pad respectively.

Illustratively, the method of forming the redistribution layer comprises:

depositing a seed layer on the bottom and sidewalls of the via;

the re-wiring layer is formed on the seed layer by electroplating.

Illustratively, prior to forming the redistribution layer, the method further comprises:

and forming a diffusion barrier layer on the side wall of the through hole and the surface of the structural support layer.

Illustratively, the covering the dry film layer on at least part of the surface of the rewiring layer includes:

pasting a dry film layer on at least part of the surface of the rewiring layer through a vacuum film pasting machine;

and baking the dry film layer.

Illustratively, the reference pressure chamber is a vacuum chamber.

Another aspect of the invention provides a MEMS device comprising:

the voltage-sensitive resistor comprises a substrate, wherein the substrate comprises a sensitive film layer, and at least one voltage-sensitive resistor is arranged in the sensitive film layer;

the structure supporting layer is positioned on the sensitive film layer, and a reference pressure cavity and a through hole penetrating through the structure supporting layer are formed in the structure supporting layer;

a rewiring layer covering the sidewall and bottom of the via and a portion of the surface of the structural support layer, wherein the rewiring layer is electrically connected to at least one of the piezoresistors;

and the dry film layer covers at least part of the surface of the rewiring layer, is attached to the side wall of the through hole and is formed with an isolation cavity between the dry film layer and the rewiring layer at the bottom of the through hole.

Illustratively, the method further comprises:

the substrate further comprises a base layer and an insulating layer positioned on the base layer, a cavity penetrating through the base layer is formed in the base layer, and the sensitive film layer is positioned on the insulating layer.

Illustratively, the method further comprises:

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

a diffusion barrier layer covering the sidewall of the via and the surface of the structural support layer;

a pad on the first dielectric layer, part of the surface of the pad being covered by the second dielectric layer, the upper surface of the pad being in contact with the rewiring layer;

and the conductive contact holes are positioned in the first dielectric layer, and each bonding pad is electrically connected with the corresponding piezoresistor through the conductive contact holes.

Illustratively, the isolation chamber is a vacuum chamber.

Illustratively, the reference pressure chamber is a vacuum chamber.

In yet another aspect, the present invention provides an electronic device including the MEMS device described above.

According to the MEMS device and the preparation method thereof, the dry film layer is used as the protective layer of the rewiring layer, the dry film layer is attached to the side wall of the through silicon via, and the isolation cavity is reserved at the bottom of the through silicon via, so that the rewiring layer in the through hole is protected, oxidation and corrosion of the rewiring layer in the through hole are avoided, and meanwhile, due to the existence of the isolation cavity, tearing force of bottom metal caused by shrinkage force generated by the dry film layer when the dry film layer is processed (for example baked) is avoided, and further damage of the rewiring layer at the bottom of the through hole is avoided.

Drawings

The following drawings are included to provide an understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and their description to explain the principles of the invention.

In the accompanying drawings:

FIG. 1 is a schematic cross-sectional view of a device obtained by implementing a method for fabricating a MEMS device according to the prior art;

FIG. 2 is a flow chart illustrating a method of fabricating a MEMS device in accordance with an embodiment of the present invention;

fig. 3 shows a schematic cross-sectional view of a device obtained by implementing a method for manufacturing a MEMS device according to an embodiment of the present invention.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention 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 invention to those skilled in the art. In the drawings, the size of layers and regions, as well as the relative sizes, may be exaggerated for clarity. Like numbers refer to like elements throughout.

It will be understood that when an element or layer is referred to as being "on," "adjacent," "connected to," or "coupled to" another element or layer, it can be directly on, adjacent, connected, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled 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. may 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 invention.

Spatially relative terms, such as "under," "below," "beneath," "under," "above," "over," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature 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 and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "under" or "beneath" other elements would then be oriented "on" the other elements or features. Thus, the exemplary terms "below" and "under" may include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 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 the associated listed items.

Embodiments of the invention are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. In this way, variations from the illustrated shape due to, for example, manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be limited to the particular shapes of the regions illustrated herein, but rather include deviations in shapes that result, for example, from manufacturing. For example, an implanted region shown as a rectangle typically has rounded or curved features and/or implant concentration gradients at its edges rather than a binary change from implanted to non-implanted regions. Also, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface over which the implantation is performed. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the present invention.

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 invention 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 specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In order to provide a thorough understanding of the present invention, detailed steps and structures will be presented in the following description in order to illustrate the technical solution presented by the present invention. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments in addition to these detailed descriptions.

Therefore, in view of the foregoing technical problems, the present invention proposes a method for manufacturing a MEMS device, as shown in fig. 2, which mainly includes the following steps:

step S1, providing a substrate, wherein the substrate comprises a sensitive film layer, at least one piezoresistor is arranged in the sensitive film layer, a structural supporting layer is arranged on the sensitive film layer, a reference pressure cavity is formed in the structural supporting layer, and a through hole penetrating through the structural supporting layer is formed at the outer side of the reference pressure cavity;

s2, forming a rewiring layer on the side wall and the bottom of the through hole and the surface of the structural support layer, wherein the rewiring layer is electrically connected with at least one piezoresistor;

and S3, covering a dry film layer on at least part of the surface of the rewiring layer, attaching the dry film layer to the rewiring layer positioned on the side wall of the through hole, and forming an isolation cavity between the dry film layer and the rewiring layer at the bottom of the through hole.

According to the MEMS device and the preparation method thereof, the dry film is used as the protective layer of the rewiring layer, the dry film layer is attached to the side wall of the through silicon via, and the isolation cavity is reserved at the bottom of the through silicon via, so that the rewiring layer in the through hole is protected, oxidation and corrosion of the rewiring layer in the through hole are avoided, and meanwhile, due to the existence of the isolation cavity, tearing force of bottom metal caused by shrinkage force generated by the dry film layer when the dry film layer is processed (for example baked) is avoided, and further damage of the rewiring layer at the bottom of the through hole is avoided.

Example 1

Next, a method for manufacturing a MEMS device of the present invention will be described in detail with reference to fig. 2 to 3, wherein fig. 2 shows a flowchart of a method for manufacturing a MEMS device according to an embodiment of the present invention; fig. 3 shows a schematic cross-sectional view of a device obtained by implementing a method for manufacturing a MEMS device according to an embodiment of the present invention.

Illustratively, as shown in FIG. 2, the method of fabricating the MEMS device of the present invention comprises the steps of:

firstly, step S1 is executed, a substrate is provided, the substrate comprises a sensitive film layer, at least one piezoresistor is arranged in the sensitive film layer, a structural supporting layer is arranged on the sensitive film layer, a reference pressure cavity is formed in the structural supporting layer, and a through hole penetrating through the structural supporting layer is formed at the outer side of the reference pressure cavity.

The MEMS device may be any suitable device known to those skilled in the art, and in this embodiment, the technical solution of the present invention is mainly explained and illustrated by taking the case that the MEMS device is a MEMS absolute pressure sensor as an example.

Specifically, in one example, as shown in fig. 3, the substrate is a silicon-on-insulator (SOI) substrate including 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 may 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 may be silicon-on-insulator (SSOI), silicon-germanium-on-insulator (S-SiGeOI), silicon-germanium-on-insulator (SiGeOI), germanium-on-insulator (GeOI), or the like, so long as there is a sensitive film thereon.

In one example, as shown in fig. 3, a first side of the substrate is etched to form a cavity 314, the cavity 314 extending through the base layer 300.

In one example, as shown in fig. 3, the insulating layer 301 is a buried insulating layer of an SOI substrate, the insulating layer 301 functioning as an etch stop layer in the fabrication of the cavity 314. The insulating layer 301 may comprise any of a number of dielectric materials, non-limiting examples including oxides, nitrides, and oxynitrides, especially oxides, nitrides, and oxynitrides of silicon. The insulating layer 301 can be formed using any of several methods, non-limiting examples of which include an ion implantation method, a thermal or plasma oxidation or nitridation method, a chemical vapor deposition method, and a physical vapor deposition method. The buried insulating layer typically has a thickness of 0.1 to 2 microns, but in this embodiment one skilled in the art can adapt accordingly to the actual needs. In this embodiment, silicon dioxide is used for the insulating layer 301.

In one example, as shown in FIG. 3, the sensitive film 302 is a silicon-based film. The thickness of the sensitive film layer affects linearity and sensitivity, and in general, the thinner the sensitive film layer, the higher the sensitivity of pressure measurement, but the thinner the sensitive film layer will result in larger film deflection, resulting in reduced linearity. In this embodiment, it will be appreciated by those skilled in the art that the thickness of the sensitive film layer 302 should be selected to be appropriate according to actual needs.

In one example, as shown in FIG. 3, the piezoresistors 311 are formed and a Wheatstone bridge connection is formed by photolithography and ion implantation of the sensitive film layer 302. Those skilled in the art will recognize that since the process of forming the sensitive film and the varistor is well established, detailed description of the process will not be repeated here, and reference may be made to conventional designs and process parameters in the art.

In one example, as shown in fig. 3, 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 through the dielectric layer 303 and exposes the varistor, and metal is filled in the contact hole to form a conductive contact hole 312. The first dielectric layer 303 may comprise any one of several dielectric materials, non-limiting examples including oxides, nitrides, and oxynitrides, especially oxides, nitrides, and oxynitrides of silicon. In this embodiment, the first dielectric layer 303 may be silicon nitride.

In one example, as shown in fig. 3, a pad 313 is disposed on the first dielectric layer 303, and the pad is electrically connected to the corresponding piezoresistor through a conductive contact hole and is used as an input/output port of the pressure sensor chip. Subsequently, a second dielectric layer 304 is deposited, the second dielectric layer 304 covering the first dielectric layer 303 and the pads 313. The second dielectric layer 304 may be made of the same material as the insulating layer 301 or a different material. In this embodiment, the second dielectric layer 304 is silicon dioxide. Alternatively, the material of the pad 313 may be one or more metals selected from aluminum, copper, gold, titanium, sodium, platinum, etc. In this embodiment, the bonding pad 313 is aluminum. The second dielectric layer 304 is then planarized to obtain a planar surface in preparation for subsequent processing.

In one example, as shown in fig. 3, the structural support layer 305 is a silicon layer, and the method of forming a reference pressure cavity in the structural support layer includes: the structural support layer 305 is etched to form a reference pressure cavity 310. In this embodiment, the reference pressure chamber is a vacuum chamber. In some embodiments, the reference pressure chamber may also be a non-vacuum chamber of known pressure. Illustratively, a bond and layer is deposited on the side of the structural support layer 305 where the reference pressure cavity 310 is formed. The bonding layer may be formed before the reference pressure chamber is formed, or may be formed after the reference pressure chamber is formed. The bonding layer can be made of silicon oxide, silicon nitride and silicon oxynitride.

Illustratively, the side of the structural support layer 305 on which the bonding layer is deposited is bonded to the sensitive film layer 302 using a bonding process to form a unitary body, and more specifically, the side of the structural support layer 305 on which the bonding layer is deposited is bonded to the second dielectric layer 304 using a bonding process to form a unitary body. In some embodiments, instead of depositing the bonds and layers, the side of the structural support layer 305 where the reference pressure cavity 310 is formed may be directly bonded to the second dielectric layer 304 to form a unitary body. The post-bond structural support layer 305 is located over the sensitive film layer 302. The bonding process may use one of low temperature electrostatic-free bonding, anodic bonding, and the like. In an alternative embodiment, after the bonding process, the structural support layer 305 may also be thinned to increase heat dissipation and reduce the thickness of the subsequent via, as well as reduce the difficulty of subsequent via fabrication and filling.

In one example, as shown in fig. 3, structural support layer 305 is etched to form a via 309, via 309 extending through structural support layer 305, and then second dielectric layer 304 is continued to be etched to expose a portion of the surface of pad 313. In this embodiment, the etching process may be a deep reactive ion etching process. To prevent shorting between devices and to protect against isolation, a diffusion barrier 306 is deposited on the surface of the structural support layer 305 and the sidewalls of the via 309.

Subsequently, a step S2 is performed to form a redistribution layer on the sidewall and bottom of the via and on the surface of the structural support layer, wherein the redistribution layer is electrically connected to at least one of the piezoresistors, for example, a bottom contact pad of the redistribution layer, so as to electrically connect at least one of the piezoresistors through a pad.

In one example, as shown in fig. 3, a re-wiring layer 307 is formed on the sidewalls and bottom of the via 309 and the surface of the structural support layer 305, the re-wiring layer 307 being bonded to the upper surface of the pad 313. The method of forming the re-wiring layer 307 includes:

depositing a seed layer on the bottom and sidewalls of the via 309;

a re-wiring layer 307 is formed on the seed layer by electroplating.

In this embodiment, the seed layer is formed by electroplating or electroless plating. In some embodiments, the seed layer may be formed using physical vapor deposition or a suitable technique. It should be noted that the seed layer is a metal layer, and may include one or more metal layers. For example, the seed layer may include a first metal layer, which may be a titanium layer, and a second metal layer, which may be a copper layer, on the first metal layer. In this embodiment, the seed layer may be a copper layer. In some embodiments, other suitable metals may be used for the seed layer. In this embodiment, the rerouting layer 307 may be a plurality of layers, and the plurality of rerouting layers 307 may be formed by repeatedly performing an electroplating process.

In one example, as shown in fig. 3, the rewiring layer 307 connects the vias, pads, and internal wiring of the external circuit board, enabling 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 film layer 302 deforms, so that the piezoresistor 311 in the sensitive film layer 302 deforms, the resistance value of the piezoresistor 311 changes due to the piezoresistance effect, and the pressure is measured by converting the resistance value into the corresponding electrical signal change through electrical connection.

And finally, executing step S3, wherein at least part of the surface of the rewiring layer is covered with a dry film layer, the dry film layer is attached to the rewiring layer positioned 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. In one example, as shown in fig. 3, a dry film layer 308 is first adhered to at least a portion of the surface of the redistribution layer 307 by a vacuum film press, and then the dry film layer 308 is adhered to the redistribution layer 307 on the sidewall of the through hole 309 by vacuum heating through a vacuum cavity, and an isolation cavity is formed between the bottom dry film layer 308 and the redistribution layer 307 of the through hole 309. In this embodiment, the isolation chamber is a vacuum chamber. In this embodiment, the temperature range of the vacuum compression molding process is 90 to 95 degrees celsius. In this way, during the subsequent baking process, the compressive force generated by shrinkage of the dry film layer 308 will not cause a tearing force on the bottom metal of the through hole 309, so as to avoid damaging the bottom metal of the through hole 309. The composition of the dry film layer 308 includes one or more of melamine compounds (melaminecom), alkoxy siloxanes (alcoxysiloxane), and organic ammonium salts (Organicammonium salt).

The key steps of the method for manufacturing the MEMS device of the present invention are described so far, and the manufacturing of the complete MEMS device may further include other steps, which are not described in detail herein.

In summary, according to the preparation method of the MEMS device, the dry film layer is used as the protective layer of the rewiring layer, the dry film layer is attached to the side wall of the through silicon via, and the isolation cavity is reserved at the bottom of the through silicon via, so that the rewiring layer inside the through hole is protected, oxidation and corrosion of the rewiring layer inside the through hole are avoided, and meanwhile, due to the existence of the isolation cavity, tearing force of bottom metal caused by shrinkage force generated by the dry film layer when the dry film layer is processed (for example baked) can be avoided, and further damage of the rewiring layer at the bottom of the through hole is avoided.

Example two

The invention also provides a MEMS device prepared by the method in the first embodiment.

Hereinafter, a MEMS device according to an embodiment of the present invention will be explained and illustrated with reference to fig. 3, wherein the same structure as in the first embodiment is not described in detail herein.

Specifically, as shown in fig. 3, the MEMS device of the present invention includes:

a substrate, wherein the substrate comprises a sensitive film layer 302, and at least one piezoresistor 311 is arranged in the sensitive film layer 302;

a structural support layer 305 located on the sensitive film layer 302, wherein a reference pressure cavity 310 and a through hole 309 penetrating the structural support layer 305 are formed in the structural support layer 305;

a rewiring layer 307 covering the sidewalls and bottom of the via 309 and a portion of the surface of the structural support layer 305, wherein the rewiring layer electrically connects at least one of the piezoresistors;

and a dry film layer 308 covering at least part of the surface of the re-wiring layer 307, wherein the dry film layer 308 is attached to the sidewall of the through hole 309, and an isolation cavity is formed between the dry film layer 308 and the re-wiring layer 307 at the bottom of the through hole 309.

Specifically, as shown in fig. 3, the substrate is a silicon-on-insulator (SOI), and 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 may 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 may be silicon-on-insulator (SSOI), silicon-germanium-on-insulator (S-SiGeOI), silicon-germanium-on-insulator (SiGeOI), germanium-on-insulator (GeOI), or the like, so long as there is a sensitive film thereon. In this embodiment, the insulating layer 301 may be a silicon oxide layer. In this embodiment, the sensitive film 302 may be a silicon-based film. In this embodiment, the structural support layer 305 may be a silicon layer. In this embodiment, the re-wiring layer 307 is formed based on a copper seed layer by electroplating.

Further, the MEMS device of the present invention further comprises:

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

a diffusion barrier 306 covering the sidewalls of the via 309 and the surface of the structural support layer 305;

a pad 313, wherein a part of the surface of the pad 313 is covered by the second dielectric layer 304, and the upper surface of the pad 313 is attached to the redistribution layer 307;

and a conductive contact hole 312, located in the first dielectric layer 303, where each bonding pad is electrically connected to a corresponding varistor through the conductive contact hole.

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

The description of the structure of the MEMS device of the present invention is thus completed, and other constituent structures may be included in the complete device, which will not be described in detail herein.

Because the MEMS device is provided with the dry film layer as the protective layer of the rewiring layer, the dry film layer is attached to the side wall of the through silicon via, and the isolation cavity is reserved at the bottom of the through silicon via, the rewiring layer inside the through hole is protected, oxidation and corrosion of the rewiring layer inside the through hole are avoided, and meanwhile, due to the existence of the isolation cavity, the tearing force of the bottom metal caused by the shrinkage force generated by the dry film layer when the dry film layer is processed (for example baked) is avoided, and further, the damage of the rewiring layer at the bottom of the through hole is avoided.

Example III

In another embodiment of the present invention, an electronic apparatus is provided, including the MEMS device described in the second embodiment. The MEMS device is the MEMS device described in the second embodiment or the MEMS device obtained by the preparation method described in the first embodiment.

The electronic device of this embodiment may be any electronic product or apparatus such as 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 video camera, a recording pen, an MP3, an MP4, and a PSP, and may also be any intermediate product including the MEMS device. The electronic device provided by the embodiment of the invention has better performance due to the adoption of the MEMS device.

Although a number of embodiments have been described herein, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various modifications and alterations may be made in the arrangement and/or component parts of the subject matter within the scope of the disclosure, the drawings, and the appended claims. In addition to modifications and variations in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims (14)

1. A method of making a MEMS device, the method comprising:

providing a substrate, wherein the substrate comprises a sensitive film layer, at least one piezoresistor is arranged in the sensitive film layer, a structural supporting layer is arranged on the sensitive film layer, a reference pressure cavity is formed in the structural supporting layer, and a through hole penetrating through the structural supporting layer is formed at the outer side of the reference pressure cavity;

forming a rewiring layer on the side wall and the bottom of the through hole and the surface of the structural support layer, wherein the rewiring layer is electrically connected with at least one piezoresistor;

and a dry film layer is covered on at least part of the surface of the rewiring layer, the dry film layer is attached to the rewiring layer positioned 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.

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

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

4. A method according to claim 3, wherein the dielectric layer comprises a first dielectric layer and a second dielectric layer, wherein a conductive contact hole is further provided in the first dielectric layer, a pad is provided on the first dielectric layer, the second dielectric layer covers the first dielectric layer and a part of the surface of the pad, each pad is electrically connected to the corresponding varistor through the conductive contact hole, and each rewiring layer is electrically connected to one pad respectively.

5. The method of claim 1, wherein the method of forming the re-routing layer comprises:

depositing a seed layer on the bottom and sidewalls of the via;

the re-wiring layer is formed on the seed layer by electroplating.

6. The method of claim 1, wherein prior to forming the re-routing layer, the method further comprises:

and 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 the dry film layer on at least a portion of the surface of the rewiring layer comprises:

pasting a dry film layer on at least part of the surface of the rewiring layer through a vacuum film pasting machine;

and baking the dry film layer.

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

9. A MEMS device, the MEMS device comprising:

the voltage-sensitive resistor comprises a substrate, wherein the substrate comprises a sensitive film layer, and at least one voltage-sensitive resistor is arranged in the sensitive film layer;

the structure supporting layer is positioned on the sensitive film layer, and a reference pressure cavity and a through hole penetrating through the structure supporting layer are formed in the structure supporting layer;

a rewiring layer covering the sidewall and bottom of the via and a portion of the surface of the structural support layer, wherein the rewiring layer is electrically connected to at least one of the piezoresistors;

and the dry film layer covers at least part of the surface of the rewiring layer, is attached to the side wall of the through hole and is formed with an isolation cavity between the dry film layer and the rewiring 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 positioned on the base layer, a cavity penetrating through the base layer is formed in the base layer, and the sensitive film layer is positioned on the insulating layer.

11. The MEMS device of claim 9, wherein the MEMS device further comprises:

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

a diffusion barrier layer covering the sidewall of the via and the surface of the structural support layer;

a pad on the first dielectric layer, part of the surface of the pad being covered by the second dielectric layer, the upper surface of the pad being in contact with the rewiring layer;

and the conductive contact holes are positioned in the first dielectric layer, and each bonding pad is electrically connected with the corresponding piezoresistor through the conductive contact holes.

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

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

14. An electronic device, characterized in that it comprises a MEMS device as claimed in one of claims 9 to 13.

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