CN222293614U - MEMS chip and electronic equipment - Google Patents

Abstract

The embodiment of the utility model discloses an MEMS chip and electronic equipment, wherein the MEMS chip comprises a substrate, and a vibrating diaphragm, a supporting layer and a back electrode plate which are arranged on the same side of the substrate, wherein the vibrating diaphragm, the supporting layer and the back electrode plate are sequentially stacked in the thickness direction of the substrate, the supporting layer comprises a first part and a second part filled in the first part, and the expansion coefficient of the first part is smaller than that of the second part. The supporting layer is arranged in the utility model, so that the stress state of the whole supporting layer can be improved, and the total compressive stress of one side of the substrate provided with the vibrating diaphragm can be reduced, thereby improving the warping state of the whole MEMS chip. Compared with the prior art, the method for reducing the warpage of the MEMS chip by increasing the thickness of the back electrode plate has the advantages that the original size of the MEMS chip is not changed, the whole chip becomes heavier and thicker, the heat conduction performance of the chip is not reduced, and the performance and the service life of electronic elements are not influenced.

Description

MEMS chip and electronic equipment

Technical Field

The utility model relates to the technical field of micro-electromechanical sensors, in particular to an MEMS chip and electronic equipment.

Background

The MEMS chip is a semiconductor chip integrated with a micro-mechanical device and an electronic element, and a micro-level mechanical structure is manufactured by means of a micro-nano processing technology, so that the chip has the functions of sensing, controlling and controlling micro objects. The conventional MEMS capacitive pressure chip generally includes a substrate and a plurality of membrane structures stacked on a surface of the substrate in a thickness direction of the substrate, such as a diaphragm and a back plate stacked on the surface of the substrate. When the film is coated layer by layer, the substrate and the film can be heated and cooled simultaneously, because the expansion coefficient of the substrate and the expansion coefficient of the film are different or the Young modulus of the substrate and the Young modulus of the film are different, so that after cooling, the shrinkage degree of the substrate and the film is also different, and after the film is coated for a plurality of times, the MEMS chip is in an upward convex warping shape as a whole.

When the MEMS chip as a whole assumes a convex and warped shape, the internal structure of the chip may be overstressed, thereby impairing mechanical properties. This can lead to problems such as brittle rupture of the film, material fatigue, and failure of the nano/micro structure. Further, electronic components inside the chip may be affected by bumps and warpage, resulting in performance variations. For example, the capacitance value of the capacitor, the inductance value of the inductor, etc. may be shifted, resulting in inaccuracy of the measurement result and degradation of system performance. In particular, when the MEMS chip is applied to a microphone, the MEMS microphone has a high requirement on signal-to-noise ratio, which is often 68dB or more and 70dB or more, and when the diaphragm is stressed, the mechanical sensitivity is reduced, which affects the signal-to-noise ratio of the MEMS microphone.

Referring to fig. 1, in practical application, the ideal state of the MEMS chip is a "no warp" state, so that the deformation of the diaphragm becomes the only variable of the output variable capacitance, but slight warp is also allowed based on comprehensive consideration of various aspects of cost, process, and the like. The current common way to improve the warpage of the MEMS chip is to thicken the back plate, but increasing the thickness of the back plate will cause the whole chip to become heavier and thicker, and reduce the heat conductivity of the chip, resulting in the temperature rise of the chip during operation, which affects the performance and lifetime of the electronic component. For example, when the MEMS chip is used in a microphone, increasing the thickness of the backplate can result in increased thermal noise in the system, further reducing the signal-to-noise ratio of the finished product.

Disclosure of utility model

The embodiment of the utility model provides an MEMS chip and electronic equipment, which are used for improving and improving the warping phenomenon of the MEMS chip on the premise of not affecting the performance of the MEMS chip.

In order to solve the technical problems, the embodiment of the utility model discloses the following technical scheme:

In one aspect, the MEMS chip comprises a substrate, a vibrating diaphragm, a first supporting layer and a back electrode plate, wherein the vibrating diaphragm, the first supporting layer and the back electrode plate are sequentially stacked in the thickness direction of the substrate, the first supporting layer comprises a first part and a second part, and the first part and the second part are nested;

wherein the coefficient of expansion of the first portion (201) is smaller than the coefficient of expansion of the second portion (202).

In addition to or in lieu of one or more of the features disclosed above, the Young's modulus of the first portion (201) is less than the Young's modulus of the second portion (202).

In addition to or in lieu of one or more of the features disclosed above, in a thickness direction of the substrate, a projection of the backplate covers a projection of the second portion, which is within a projection of the diaphragm.

In addition to or in lieu of one or more of the features disclosed above, the first support layer may further comprise a cavity extending through its thickness, the second portion being a continuous annular structure, the second portion being disposed concentric with the cavity.

In addition to or in lieu of one or more of the features disclosed above, the second portion includes a first annular structure and a second annular structure, the first annular structure having a diameter greater than a diameter of the second annular structure, the first annular structure and the second annular structure being concentric rings.

In addition to or in lieu of one or more of the features disclosed above, the first support layer may further comprise a cavity extending through its thickness, and the second portion may comprise a plurality of second portions uniformly distributed along an edge of the cavity.

In addition to or in lieu of one or more of the features disclosed above, the projected shapes of adjacent ones of the second portions are different in the thickness direction of the substrate, and the projected shapes of second portions that are symmetrical about the center of the cavity are the same.

In addition to, or as an alternative to, one or more of the features disclosed above, the projected shape is one or more of polygonal, arcuate.

In addition to or in lieu of one or more of the features disclosed above, the first portion is silicon oxide and the second portion is silicon nitride.

In addition to or in lieu of one or more of the features disclosed above, the substrate includes a back cavity extending through its thickness, the projection range of the cavity covering the projection range of the back cavity in the thickness direction of the substrate.

In addition to or in lieu of one or more of the features disclosed above, a second support layer is included between the substrate and the diaphragm, the substrate including a back cavity extending through the substrate in a thickness direction thereof, the back cavity also extending through the second support layer.

In another aspect, an electronic device is provided that includes any of the MEMS chips disclosed above.

The technical scheme has the advantages that the first supporting layer between the vibrating diaphragm and the back electrode plate can avoid direct contact between the back electrode plate and the vibrating diaphragm, and when the MEMS chip is manufactured, the expansion coefficient of the first supporting layer is different from that of the vibrating diaphragm, or the Young modulus of the first supporting layer is different from that of the vibrating diaphragm, and in the processes of heating through a coating film and cooling through the coating film, the residual stress state of the first supporting layer is usually compressive stress. The first supporting layer comprises a first part and a second part filled in the first part, the expansion coefficient of the first part is smaller than that of the second part, or the Young's modulus of the first part is smaller than that of the first part, and the residual stress state of the first part is compressive stress and the residual stress state of the second part is tensile stress in the process of coating temperature rising and coating temperature lowering, so that the integral stress state of the first supporting layer can be improved, the total compressive stress on one side of a substrate provided with a vibrating diaphragm is reduced, and the integral warping state of the MEMS chip is improved. Compared with the prior art, the method for reducing the warpage of the MEMS chip by increasing the thickness of the back electrode plate has the advantages that the original size of the MEMS chip is not changed, the whole chip becomes heavier and thicker, the heat conduction performance of the chip is not reduced, and the performance and the service life of electronic elements are not influenced.

Drawings

The technical solution and other advantageous effects of the present utility model will be made apparent by the following detailed description of the specific embodiments of the present utility model with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of chip warpage provided in accordance with an embodiment of the present application;

FIG. 2 is a schematic diagram of a MEMS chip according to an embodiment of the present application;

FIG. 3 is a schematic view of a first support layer according to an embodiment of the present application;

FIG. 4 is a second schematic view of a first support layer according to an embodiment of the present application;

FIG. 5 is a third schematic view of a first support layer according to an embodiment of the present application;

Fig. 6 is a schematic diagram of a first support layer according to an embodiment of the present application.

Reference numerals illustrate:

000. a substrate, 001, back cavity;

100. a vibrating diaphragm;

200. First support layer 201, first part 202, second part 2021, first annular structure 2022, second annular structure 203, cavity;

400. 401, through hole;

500. And a second support layer.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present utility model more apparent, the present utility model will be further described in detail with reference to the accompanying drawings and detailed description. It should be understood that the detailed description is intended to illustrate the utility model, and not to limit the utility model.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present utility model, the meaning of "plurality" means two or more, unless specifically defined otherwise.

In the description of the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, directly connected, indirectly connected via an intermediate medium, or in communication between two elements or in interaction with each other. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.

An embodiment of the present utility model discloses a MEMS chip, referring to fig. 2, which includes a substrate 000, and a diaphragm 100, a first support layer 200, and a back plate 400 on the same side of the substrate 000. In the thickness direction of the substrate 000, the diaphragm 100, the first support layer 200, and the back plate 400 are sequentially stacked. The diaphragm 100 and the back electrode plate 400 are used for forming two electrodes of a capacitor, the first supporting layer 200 is used for supporting the back electrode plate 400, and isolating the back electrode plate 400 from the diaphragm 100, so that a deformation space is reserved for the diaphragm 100, and the back electrode plate 400 can be prevented from being in direct contact with the diaphragm 100.

In some embodiments, a second supporting layer 500 is disposed between the diaphragm 100 and the substrate 000, where the second supporting layer 500 can prevent the diaphragm 100 from directly contacting the substrate 000, and in some embodiments, the back plate 400 is provided with a plurality of through holes 401 penetrating through its thickness, and the substrate 000 includes a back cavity 001 penetrating through its thickness. By providing the second support layer 500, the influence on the diaphragm 100 when the back cavity 001 is provided can be avoided, and the back cavity 001 also normally penetrates through the second support layer 500. The second support layer 500 has a smaller thickness than the first support layer 200, and the residual stress generated by the second support layer 500 has a negligible effect on the MEMS chip when the MEMS chip is fabricated.

In preparing the MEMS chip, the second support layer 500, the diaphragm 100, the first support layer 200, and the back plate 400 are sequentially formed on one side surface of the substrate 000 through a plating process. The main reason for the warp of the MEMS chip is that when the film plating is performed, the film structure serving as the substrate and the film structure plated on the substrate are heated to a certain temperature at the same time, and after the film plating is completed, the film structure serving as the substrate and the film structure plated on the substrate are cooled to an initial temperature at the same time, because the expansion coefficients of the film structure serving as the substrate are different or the Young modulus of the film structure is different, or when the Young modulus of the film structure serving as the substrate is also smaller than the expansion coefficient of the film structure plated on the substrate, the film structure plated on the substrate generates tensile stress, otherwise, the film structure plated on the substrate generates compressive stress.

In order to improve the warpage phenomenon of the MEMS chip without affecting the performance of the MEMS chip, and particularly but not by way of limitation, the embodiment of the present application proposes a MEMS chip structure, and with continued reference to fig. 2, the first supporting layer 200 includes a first portion 201 and a second portion 202, where the first portion 201 and the second portion 202 are nested, and the expansion coefficient of the first portion 201 is smaller than the expansion coefficient of the second portion 202, or the young's modulus of the first portion 201 is also smaller than the young's modulus of the second portion 202.

Specifically, when the MEMS chip is manufactured, the expansion coefficient of the first supporting layer 200 is different from that of the diaphragm 100, or the young's modulus of the first supporting layer 200 is different from that of the diaphragm 100, and in the process of heating up the coating and cooling down the coating, the residual stress state of the first supporting layer 200 is usually compressive stress. In the disclosed embodiment of the application, the residual stress state of the first portion 201 is compressive stress and the residual stress state of the second portion 202 is tensile stress in the process of heating and cooling the coating by the first supporting layer 200, so that the stress state of the whole first supporting layer 200 can be improved, the total compressive stress of one side of the substrate 000 where the vibrating diaphragm 100 is arranged can be reduced, and the warping state of the whole MEMS chip can be improved.

In the thickness direction of the substrate 000, the projection of the backplate 400 covers the projection of the second portion 202, the projection of the second portion 202 being located within the projection of the diaphragm 100. In various embodiments, the second portion 202 has a different shape, and in some embodiments, the first support layer 200 further includes a cavity 203 extending through its thickness, and the second portion 202 is a continuous annular structure, and the second portion 202 is concentric with the cavity 203, as shown in fig. 3, and in some embodiments, the second portion 202 includes a plurality of continuous annular structures, and in particular, in the embodiment shown in fig. 4, the second portion 202 includes a first annular structure 2021 and a second annular structure 2022, the diameter of the first annular structure 2021 is larger than the diameter of the second annular structure 2022, and the first portion 201 is embedded between the first annular structure 2021 and the second annular structure 2022. The material of the first annular structure 2021 and the material of the second annular structure 2022 may be the same or different.

Referring to fig. 5, in some embodiments, the first support layer 200 still includes a cavity 203 extending through its thickness, unlike the previous embodiments in which the second portion 202 includes a plurality of second portions 202 evenly distributed along the edges of the cavity 203. Note that, adjacent materials of the adjacent second portions 202 may be the same or different, and materials of the second portions 202 symmetrical about the center of the cavity 203 may be the same. With continued reference to fig. 5, in some embodiments, the projected shapes of adjacent second portions 202 differ in the thickness direction of the substrate 000, and the projected shapes of second portions 202 that are symmetrical about the center of the cavity 203 are the same, and with reference to fig. 6, in some embodiments, the projected shapes of each second portion 202 are the same in the thickness direction of the substrate 000. It is worth mentioning that the projection shape may be polygonal, arcuate or irregular, and specifically, the irregular pattern may be petal-shaped or the like. It should be noted that, in some embodiments, the projection range of the cavity 203 covers the projection range of the back cavity 001 in the thickness direction of the substrate 000.

Further, in different embodiments, the first portion 201 may be made of different insulating materials, which has enough mechanical properties to be not easy to break during etching, and the first portion 201 is silicon oxide and the second portion 202 is silicon nitride in the embodiments provided by the present application. In some embodiments, diaphragm 100 is made of polysilicon and substrate 000 is made of silicon.

At least one embodiment of the present application also provides an electronic device including any of the MEMS chips disclosed above.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (11)

1. The MEMS chip is characterized by comprising a substrate (000), a vibrating diaphragm (100), a first supporting layer (200) and a back electrode plate (400) which are arranged on the same side of the substrate (000), wherein the vibrating diaphragm (100), the first supporting layer (200) and the back electrode plate (400) are sequentially stacked in the thickness direction of the substrate (000), the first supporting layer (200) comprises a first part (201) and a second part (202), the first part (201) and the second part (202) are nested, and the expansion coefficient of the first part (201) is smaller than that of the second part (202).

2. The MEMS chip, as recited in claim 1, wherein the young's modulus of the first portion (201) is smaller than the young's modulus of the second portion (202).

3. The MEMS chip, as set forth in claim 1, characterized in that the projection of the backplate (400) covers the projection of the second portion (202) in the thickness direction of the substrate (000), the projection of the second portion (202) being located within the projection of the diaphragm (100).

4. A MEMS chip according to claim 3, wherein the first support layer (200) further comprises a cavity (203) through its thickness, the second portion (202) being of continuous annular structure, the second portion (202) being arranged concentrically with the cavity (203).

5. The MEMS chip, as recited in claim 4, wherein the second portion (202) comprises a first annular structure (2021) and a second annular structure (2022), the first annular structure (2021) having a diameter greater than a diameter of the second annular structure (2022), the first annular structure (2021) and the second annular structure (2022) being concentrically disposed.

6. A MEMS chip according to claim 3, wherein the first support layer (200) further comprises a cavity (203) extending through its thickness, the second portion (202) comprising a plurality of second portions (202) uniformly distributed along the edges of the cavity (203).

7. The MEMS chip, as recited in claim 6, wherein the projected shapes of adjacent second portions (202) are different in the thickness direction of the substrate (000), and the projected shapes of second portions (202) symmetrical about the center of the cavity (203) are the same.

8. The MEMS chip of claim 7, wherein the projected shape is one or more of polygonal, arcuate.

9. The MEMS chip, as recited in any of claims 1-8, wherein the first portion (201) is silicon oxide and the second portion (202) is silicon nitride.

10. The MEMS chip, as recited in any of claims 1-8, further comprising a second support layer (500) between the substrate (000) and the diaphragm (100), the substrate (000) comprising a back cavity (001) through its thickness, the back cavity (001) also through the second support layer (500).

11. An electronic device comprising a MEMS chip as claimed in any one of claims 1-10.