WO2021082052A1

WO2021082052A1 - Microfilter and mems sensor assembly

Info

Publication number: WO2021082052A1
Application number: PCT/CN2019/116566
Authority: WO
Inventors: 畠山庸平; 林育菁
Original assignee: 潍坊歌尔微电子有限公司
Priority date: 2019-10-31
Filing date: 2019-11-08
Publication date: 2021-05-06
Also published as: CN110809207B; CN110809207A

Abstract

Disclosed is a microfilter, comprising a bearing member (201) and a filter membrane (102). The bearing member (201) is provided with a through cavity (205) formed therein and penetrating same in the thickness direction thereof. The filter membrane (102) is stacked on the bearing member (201). The filter membrane (102) comprises a first portion (104) covering one opening of the through cavity (205) and a second portion (106) uncovering the opening, and the first portion (104) is surrounded by the second portion (106). Through holes (207) are arranged and distributed in the first portion (104), and the second portion (106) is jointed with the bearing member (201). The first portion (104) is connected to the second portion (106) by means of only a single beam (108), such that the first portion (104) is suspended above the through cavity (205). Further provided is an MEMS sensor assembly.

Description

Micro filters and MEMS sensor components

Technical field

The present disclosure mainly relates to a micro filter, which may be a micro filter suitable for acoustic equipment, and is used to filter dust, particles, and/or water and other substances that are not desired to enter the interior of the acoustic equipment. The present disclosure also relates to a MEMS sensor assembly.

Background technique

Nowadays, portable computing devices such as notebook computers and tablet computers are very common, as are portable communication devices such as smart phones. However, the internal space left for microphones or speakers in such devices is very limited. Therefore, microphones and speakers are getting smaller and smaller in size and becoming more and more compact. In addition, because microphones and speakers are deployed in compact portable devices, they usually need to be close to the related acoustic input or output ports of the device, so the ingress of particles and water can easily cause the malfunction of the MEMS sensor therein.

In the prior art, particle filters (also known as PB chips, micro filters) are often deployed in MEMS sensor components to prevent certain types of debris from entering them.

Films with high stress are prone to peeling, cracking, wrinkling or otherwise detaching from their substrates. Wrinkles are caused by the difference in the coefficient of thermal expansion between the filter membrane made of metal wire mesh and the carrier supporting the filter membrane, which makes the constraint condition of the edge portion of the filter membrane problematic. Therefore, PB chips are often discarded shortly after being put into operation.

A screen made of fine metal wires or through holes formed through a plurality of holes in a silicon substrate have been put into use, and a thin film with low stress is required. In addition, when depositing a suitable metal thin film on the substrate in order to manufacture the PB chip structure, it is necessary to obtain a thin film with low stress.

Recently, a micro particle filter with a double support beam or a fully clamped diaphragm structure has been developed, but this makes the stress control requirements of the dust filter membrane more stringent and makes It is difficult to reduce wrinkles at any temperature.

Summary of the invention

An object of the present disclosure is to provide a new technical solution for the micro filter.

According to a first aspect of the present disclosure, there is provided a micro filter including: a carrier having a through cavity formed therein and penetrating in a thickness direction thereof; and a filter membrane stacked on the carrier Above, the filter membrane includes a first part that covers an opening of the through cavity and a second part that does not cover the opening. The first part is surrounded by the second part, and the first part is arranged with passages. A hole, the second part is engaged with the carrier; wherein the first part is only connected to the second part by a single beam, thereby being suspended on the through cavity.

Optionally, the carrier is made of polymer material, metal, silicon or silicon dioxide.

Optionally, the filter membrane is made of an amorphous metal material.

Optionally, the filter membrane is metallic glass.

Optionally, the thickness of the filter membrane is 5 nm to 5 μm.

Optionally, the thickness of the filter membrane is 20 nm to 1000 nm.

Optionally, the inner diameter of the through hole is 1 nm to 100 μm.

Optionally, the inner diameter of the through hole is 100 nm to 10 μm.

According to a second aspect of the present disclosure, there is provided a MEMS sensor assembly, including: the micro filter according to the first aspect of the present disclosure; and a MEMS sensor having an opening and capable of sensing through the opening. Measure; wherein the micro filter is installed to the MEMS sensor in a manner to cover the opening.

Optionally, the MEMS sensor component is used in a microphone module or a microphone chip.

According to an embodiment of the present disclosure, the coefficient of thermal expansion of the filter membrane can be ignored at any temperature, and only the stress gradient needs to be considered when stress control is performed on the filter membrane.

Through the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings, other features and advantages of the present disclosure will become clear.

Description of the drawings

The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments of the present disclosure, and together with the description thereof, serve to explain the principle of the present disclosure.

Fig. 1 schematically shows an embodiment of the microfilter according to the present disclosure, in which Fig. 1(A) is a plan view of the microfilter, and Fig. 1(B) is a cross-sectional view taken along the line A-O-B in Fig. 1(A).

Detailed ways

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that unless specifically stated otherwise, the relative arrangement, numerical expressions and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation to the present disclosure and its application or use.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

The present disclosure provides a micro filter and a MEMS sensor component using the micro filter. The MEMS sensor component may be used in an acoustic device, and the acoustic device may be, for example, a microphone chip or a microphone module. For example, when the acoustic device is a microphone chip, the MEMS sensor component can be arranged on the microphone chip; when the acoustic device is a microphone module, the MEMS sensor component can be arranged on the housing or the sound hole of the microphone module. Of course, for those skilled in the art, the acoustic device may also be other types of acoustic transducers, which will not be described in detail here.

Fig. 1 schematically shows an embodiment of the microfilter according to the present disclosure, in which Fig. 1(A) is a plan view of the microfilter, and Fig. 1(B) is a cross-sectional view taken along the line A-O-B in Fig. 1(A). 1(A) and 1(B), the micro filter includes a carrier 201 and a filter membrane 102 stacked on the carrier. The carrier 201 has formed therein and penetrates in the thickness direction of the carrier 201的through cavity 205. The through cavity 205 has two openings, and each opening is located on one of the two opposite surfaces of the carrier 201. One of the two openings is covered by the filter membrane 102. A plurality of through holes 207 are arranged on the central portion 104 of the filter membrane 102 to allow air to flow therethrough. The central portion 104 faces the through cavity 205 and covers an opening of the through cavity 205. The surrounding portion 106 of the filter membrane 102 is joined to the carrier 201 without covering the opening. The central part 104 is surrounded by the surrounding part 106. The boundary 110 between the central part 104 and the surrounding part 106 is basically hollow, and only a single beam 108 connects the central part 104 to the surrounding part 106, thereby allowing the central part 104 to be suspended only by the support of the beam 108 It is placed above the through cavity 205.

Compared with a double support beam (doubly support beam) or a fully clamped diaphragm (fully clamped diaphragm) structure of the micro filter (which is not hollowed out at the boundary 110), the micro filter of the embodiment shown in FIG. 1 is free from Filter membrane folds induced by stress. Therefore, the coefficient of thermal expansion of the filter membrane can be ignored at any temperature, and only the stress gradient needs to be considered when the filter membrane is subjected to stress control.

The beam 108 may be a part of the filter membrane 102, that is, the beam 108 is integrated with the central part 104 and the surrounding part 106. In one embodiment, the beam 108 is formed by removing the filter membrane material at the boundary 110. In one embodiment, the beam 108 is integrally formed with the central part 104 and the surrounding part 106, that is, when the filter membrane 102 is initially formed, the boundary 110 is hollowed out.

Optionally, the thickness of the filter membrane 102 is 5 nm to 5 μm, preferably 20 nm to 1000 nm.

Optionally, the inner diameter of the through hole 207 is 1 nm to 100 μm, preferably 100 nm to 10 μm.

The carrier 201 may be made of polymer material, metal, silicon or silicon dioxide. The carrier 201 is beneficial to fix the filter membrane 102 in place, and is also beneficial to assembling a dust-proof chip (PB chip).

The filter membrane 102 may be a metal thin film, more preferably made of an amorphous metal material, and more preferably made of metallic glass. Since amorphous metal has irregular atomic arrangement and no specific slip surface, compared with crystalline metal, it has higher strength and excellent fatigue performance, elastic deformation ability, and shock resistance. There are several methods to produce amorphous metal materials, including extremely rapid cooling, physical vapor deposition (PVD), electroplating, pulsed laser deposition (PLD), solid state reaction, ionizing radiation, and mechanical alloying. Optionally, the filter membrane 102 is formed by a PVD process, an electroplating process, or a PLD process.

Since metallic glass is isotropic and uniform, there are basically no defects such as grain boundaries and segregation caused by polycrystalline structure, and its size effect is small. Therefore, when designing the micro filter, it is not necessary to consider the changes in physical properties due to anisotropy and size, which facilitates the structural design of the micro filter. In addition, because metallic glass is an alloy composed of multiple elements, the range of material selection in the design of a micro filter is widened, and a higher performance micro filter can be designed and manufactured.

The second aspect of the present disclosure also provides a MEMS sensor assembly, including: a micro filter as shown in the embodiment of FIG. 1; and a MEMS sensor, the MEMS sensor has an opening and can be sensed through the opening; The micro filter is mounted to the MEMS sensor in a manner to cover the opening.

Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

A micro filter is characterized in that it comprises:

The carrier has a through cavity formed therein and penetrated in the thickness direction thereof; and

The filter membrane is stacked on the carrier, the filter membrane includes a first part covering an opening of the through cavity and a second part not covering the opening, the first part is surrounded by the second part , Through holes are arranged on the first part, and the second part engages the carrier;

Wherein, the first part is only connected to the second part by a single beam, and thereby is suspended on the through cavity.
The micro filter according to claim 1, wherein the supporting member is made of polymer material, metal, silicon or silicon dioxide.
The micro filter according to claim 1, wherein the filter membrane is made of amorphous metal material.
The micro filter according to claim 3, wherein the filter membrane is made of metallic glass.
The micro filter according to claim 1, wherein the thickness of the filter membrane is 5 nm to 5 μm.
The micro filter according to claim 5, wherein the thickness of the filter membrane is 20 nm to 1000 nm.
The micro filter according to claim 1, wherein the inner diameter of the through hole is 1 nm to 100 μm.
The micro filter according to claim 7, wherein the inner diameter of the through hole is 100 nm to 10 μm.
A MEMS sensor assembly, characterized in that it comprises:

The micro filter according to any one of claims 1 to 8, and

A MEMS sensor, which has an opening and can perform sensing through the opening;

The micro filter is mounted to the MEMS sensor in a manner to cover the opening.
The MEMS sensor assembly of claim 9, wherein the MEMS sensor assembly is used in a microphone module or a microphone chip.