CN110775936A

CN110775936A - Miniature three-dimensional stacked MEMS (micro-electromechanical systems) resonance device

Info

Publication number: CN110775936A
Application number: CN201911128592.4A
Authority: CN
Inventors: 林日乐; 谢佳维; 王伟; 李文蕴; 蒋昭兴; 罗华
Original assignee: CETC 26 Research Institute
Current assignee: CETC 26 Research Institute
Priority date: 2019-11-18
Filing date: 2019-11-18
Publication date: 2020-02-11
Anticipated expiration: 2039-11-18
Also published as: CN110775936B

Abstract

The invention discloses a miniature three-dimensional stacked MEMS (micro-electromechanical systems) resonance device, which comprises a shell, a cover cap for sealing the opening of the shell and a conductive chip support, wherein the chip support and the resonance chip have the same thermal expansion coefficient, the resonance chip comprises a resonance beam and a fixing part, the resonance chip is arranged on the chip support through the fixing part and enables the resonance beam to be suspended in the air, the chip support is arranged on the inner wall of the shell and is electrically connected with the shell, an integrated chip mounting groove is arranged on the inner bottom surface of the shell below the chip support, and an integrated chip electrically connected with the shell is arranged in the integrated chip mounting groove. The chip support is adopted to connect the resonance chip and the shell, so that the resonance chip is prevented from being influenced by shell deformation and thermal stress; the miniature three-dimensional stacked MEMS resonance device disclosed by the invention can realize the miniaturization of the MEMS resonance device on the premise of meeting the stability requirement of the MEMS resonance device.

Description

Miniature three-dimensional stacked MEMS (micro-electromechanical systems) resonance device

Technical Field

The invention relates to the technical field of MEMS (micro-electromechanical systems) resonant devices, in particular to a miniature three-dimensional stacked MEMS resonant device.

Background

MEMS (Micro-Electro-Mechanical Systems) is an abbreviation of Micro-Electro-Mechanical Systems, and MEMS chip fabrication utilizes Micro-electronic processing technology, especially three-dimensional Micro-body processing technology, to fabricate various Micro-Mechanical structure sensitive chips, which are then integrated with an application-specific integrated circuit to form Micro-sized and intelligent MEMS devices and components such as sensors, actuators, optical devices, etc., such as crystal resonators, angular velocity sensors, acceleration sensors, pressure sensors, temperature sensors, etc. MEMS devices and components have the characteristics of small volume, high reliability, strong environmental adaptability, low power consumption, low cost and the like, and are widely applied to the fields of aerospace, aviation, electronics and the like, such as mobile phones, toys, digital cameras, unmanned planes, automobiles, robots, intelligent transportation, industrial automation, modern agriculture and the like.

The performance and volume of the MEMS resonator device mainly depend on the processing, assembling and packaging processes of the MEMS resonator chip, and particularly, the frequency stability and volume of the MEMS resonator device are greatly affected by the packaging method. When the MEMS resonator works, the resonance chip is in a vibration state, and when the chip is assembled and packaged, the resonance chip needs to be suspended in the air, so that the resonance beam can freely resonate. The existing MEMS resonator usually manufactures a convex fixed supporting point on a chip, the convex fixed supporting point is pasted with a packaging shell (usually made of materials such as metal, ceramic and the like), and the convex fixed supporting point is high, so that a resonant chip is suspended in the air to form a resonant space; or a gasket is manufactured, the gasket is firstly adhered to a packaging shell (usually made of materials such as metal, ceramic and the like), then the resonance chip is assembled, and the resonance chip is suspended through the height of the gasket to form a resonance space. In the chip assembly and packaging mode in the form, when the temperature changes, thermal stress can be generated due to different thermal expansion coefficients of the resonant chip material and the gasket material with the shell material, so that the structure of the resonant chip is deformed, and the resonant frequency is changed; meanwhile, when the device packaging structure is deformed by external force, the deformation can be transmitted to the resonant chip, so that the chip structure is deformed, the resonant frequency is changed, and the stability of the resonant frequency is influenced. The MEMS resonator device also needs to have a matching asic chip when operating, and the existing MEMS resonator is usually packaged separately with the MEMS resonator chip and the asic chip, and then mounted in a housing base in a stacked or side-by-side manner, as shown in fig. 5 and 6. When the MEMS resonant chip and the application specific integrated circuit chip are stacked and mounted, the MEMS resonant chip is easily affected by the heating of the application specific integrated circuit chip, and the frequency stability of the MEMS resonant chip is affected; when installing side by side, the outer casing that needs is bulky great, is unfavorable for the miniaturization, and MEMS resonance chip contacts with the shell simultaneously, and the chip structure deformation that the shell deformation leads to easily influences it and is stability.

The method is characterized in that the existing methods for reducing the influence of assembly and packaging on the performance of the MEMS resonant chip are adopted, wherein one method is to select a material with a thermal expansion coefficient close to that of a resonant chip material (usually quartz crystal or silicon crystal) to manufacture a packaging shell; secondly, the gasket is made of the same material as the chip material; thirdly, the strength of the shell is increased, and the deformation of the shell is avoided; and fourthly, the resonance chip and the special integrated circuit are designed in a miniaturized mode, the size of the resonance chip and the special integrated circuit is reduced, meanwhile, the thermal optimization design is carried out, and the influence of the heating of the special integrated circuit on the resonance chip is reduced. However, these methods have disadvantages: firstly, a shell can not be made of a material with the same thermal expansion coefficient as that of the resonant chip material; secondly, the gasket material is the same as the chip material, so that the problem of mismatch of thermal expansion coefficients can be avoided, but the structural deformation of the chip caused by the deformation of the shell cannot be avoided; thirdly, the structural strength of the shell cannot be increased without limit due to the limitation of volume, materials, process and the like; fourthly, the resonance chip and the special integrated circuit are further miniaturized, the system optimization on the whole structure and performance of the product is often needed, the difficulty is high, the realization is difficult, and the heating phenomenon of the special integrated circuit during working can not be thoroughly eliminated. The above method cannot fundamentally solve the influence of the encapsulation on the stability of the MEMS resonator device and cannot effectively solve the miniaturization problem.

Therefore, how to realize the miniaturization of the MEMS resonator device on the premise of satisfying the stability requirement of the MEMS resonator device becomes a problem that needs to be solved by those skilled in the art.

Disclosure of Invention

Aiming at the defects in the prior art, the invention needs to solve the problems that: how to realize the miniaturization of the MEMS resonance device on the premise of meeting the stability requirement of the MEMS resonance device.

In order to solve the problems in the prior art, the invention adopts the following technical scheme:

the utility model provides a miniature three-dimensional closed assembly's MEMS resonance device, including being equipped with open shell and the open block of sealed shell, still include the chip support that can electrically conduct, the chip support is the same with resonance chip thermal expansion coefficient, resonance chip includes resonance roof beam and fixed part, resonance chip passes through the fixed part and installs on the chip support and make resonance roof beam unsettled, the chip support mounting on the shell inner wall and with shell electrical connection, the shell bottom surface in the chip support below is equipped with the integrated chip mounting groove, install the integrated chip with shell electrical connection in the integrated chip mounting groove.

Preferably, the chip support comprises a support body, a resonant beam groove is formed in the end face of the support body, a fixing portion of the resonant chip is fixedly connected with the edge of the resonant beam groove, the resonant beam of the resonant chip can freely resonate at the resonant beam groove, the outer side face of the support body transversely extends to form a supporting leg, the supporting leg is fixedly mounted on the inner wall of the shell, and the supporting leg is electrically connected with the shell through a lead.

Preferably, 4 supporting legs transversely extend out of the outer side surface of the support body, and the 4 supporting legs are arranged in an X shape.

Preferably, the fixing part of the resonant chip is in a ring shape, the inner wall of the ring fixing part transversely extends to form the resonant beam, the end face of the ring fixing part is matched with the ring installation end face around the groove of the bracket body, and the end face of the ring installation fixing part is attached to the ring installation end face around the groove of the bracket body.

Preferably, a first groove extending downwards is formed in the upper end face of the shell, a second groove extending downwards is formed in the bottom face of the first groove, an integrated chip mounting groove extending downwards is formed in the bottom face of the second groove, the integrated chip is electrically connected with the bottom face of the second groove through a lead wire of spot welding, and the supporting leg of the resonant chip is mounted on the bottom face of the first groove and is electrically connected with the bottom face of the first groove through a lead wire of spot welding.

Preferably, the upper end surfaces of the supporting legs are flush with the upper end surface of the support body, and the thickness of the supporting legs is smaller than that of the support body.

Compared with the prior art, the invention has the technical effects that:

the invention adopts the X-type chip support, so that the resonance beam and the fixing part of the MEMS resonance chip can be integrally designed and processed, the fixing part does not need to be processed into a convex structure, the miniaturization of the chip size is facilitated, and the process complexity is reduced; the MEMS resonance chip is arranged at the groove by utilizing the X-shaped bracket, the cavity formed by the groove enables the resonance beam of the resonance chip to freely resonate in the cavity, and the four supporting legs extending out of the X-shaped bracket in the diagonal direction are arranged at four corners of the step of the shell to form a bottom cavity structure for mounting the ASIC chip, thereby forming a three-dimensional laminated structure which is compactly arranged: the bottom is a special integrated circuit chip, the middle is an X-shaped bracket, and the upper part is an MEMS resonance chip, so that the three-dimensional laminated structure is beneficial to reducing the volume of the MEMS resonance device and ensures the performance; the four supporting legs extending out in the diagonal direction of the X-shaped support can buffer the influence of the deformation of the shell on the MEMS resonance chip, and the stability is improved. The X-shaped support can be made of the same material as the MEMS resonant chip, so that the thermal expansion coefficients of the resonant chip and the support frame can be matched, and the influence of thermal stress is avoided. Four supporting legs of the X-shaped support are arranged at four corners of the step, the area of the bonding contact point is small, and the large-area contact between the support and the base of the shell is avoided, so that the adverse effect of large structural deformation caused by stress generated by different thermal expansion coefficients of different materials during temperature change is avoided. Meanwhile, the X-shaped support is small in bonding occupied area, does not occupy more areas of steps, and facilitates subsequent electrical connection. The micro three-dimensional stacked MEMS resonance device provided by the invention can ensure good stability while reducing the volume.

Drawings

For purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made in detail to the present invention as illustrated in the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of one embodiment of a miniature three-dimensional stacked MEMS resonator device as disclosed herein;

FIG. 2 is a top view of one embodiment of a miniature three-dimensional stacked MEMS resonator device disclosed herein with a cap removed;

FIG. 3 is a top view of one embodiment of a chip support in a micro three-dimensional stacked MEMS resonator device according to the present disclosure;

FIG. 4 is a cross-sectional view of a micro three-dimensional stacked MEMS resonator device according to the present invention after a resonant chip is bonded to a chip carrier;

fig. 5 and 6 are cross-sectional views of a MEMS resonator device in the related art.

The corresponding relation of the reference numbers in the drawings is as follows: wherein: 1-a resonant chip; 10-a resonant beam; 11-a fixed part; 2-chip support; 20-supporting feet; 21-a stent body; 22-resonant beam groove; 3-a resonant chip and chip support assembly; 41-an integrated chip; 42-a housing; 43-step; 6-MEMS resonator devices; 61-a lead; 62-a cap; 7-MEMS resonator devices of the prior art.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1 and fig. 2, the invention discloses a micro three-dimensional stacked MEMS resonator device, which includes an open housing 42, an open cap 62 for sealing the open housing 42, and a conductive chip support 2, wherein the thermal expansion coefficient of the chip support 2 is the same as that of the resonant chip 1 (the chip support 2 and the resonant chip 1 may be made of the same material), the resonant chip 1 includes a resonant beam 10 and a fixing portion 11, the resonant chip 1 is mounted on the chip support 2 through the fixing portion 11 and suspends the resonant beam 10, the chip support 2 is mounted on the inner wall of the housing 42 and electrically connected to the housing 42, an integrated chip 41 mounting groove is disposed on the inner bottom surface of the housing 42 below the chip support 2, and an integrated chip 41 electrically connected to the housing 42 is mounted in the integrated chip 41 mounting groove.

In the invention, the thickness of the resonant chip 1 is generally 80-400 microns, the materials of the resonant chip 1 and the support chip comprise quartz crystal, silicon crystal and the like, and the materials of the shell 42 and the cap 62 comprise metal, ceramic and the like. The chip support 2 is adopted to connect the resonance chip 1 and the shell 42, so that the resonance chip 1 is prevented from being influenced by the deformation and the thermal stress of the shell 42; the three-dimensional stacked structure is adopted to install the resonance chip 1, the chip support 2 and the integrated chip 41, so that the volume of the MEMS resonance device is effectively reduced.

As shown in fig. 3, in a specific implementation, the chip support 2 includes a support body 21, a resonant beam groove 22 is formed on an end surface of the support body 21, a fixing portion 11 of the resonant chip 1 is fixedly connected to an edge of the resonant beam groove 22, the resonant beam 10 of the resonant chip 1 can freely resonate at the resonant beam groove 22, an outer side surface of the support body 21 extends laterally to form a supporting leg 20, the supporting leg 20 is fixedly mounted on an inner wall of the housing 42, and the supporting leg 20 is electrically connected to the housing 42 through a lead 61.

In the invention, the thickness of the chip support 2 is generally 100-500 microns, the length of the supporting legs 20 is generally 1000-3000 microns, and the included angle between the supporting legs 20 is generally 20-160 degrees; the length and width of the bracket body 21 are consistent with or slightly wider than those of the resonant chip 1; the depth of the resonant beam groove 22 is generally 50 to 300 micrometers, and the length and width dimensions are the same as or slightly wider than those of the fixing part 11 on the resonant chip 1.

According to the invention, the chip support 2 is arranged on the inner wall of the shell 42 through the transverse supporting legs 20, the area of the bonding contact point is small, the large-area contact between the chip support 2 and the shell 42 is avoided, the adverse effect of large structural deformation caused by stress generated by different thermal expansion coefficients of different materials during temperature change is avoided, the supporting legs 20 are small in bonding occupied area, and the subsequent electrical connection is convenient.

The whole support is flaky, so that the vertical height of the resonance device can be effectively reduced. In addition, the design of arranging the resonant beam groove 22 on the support chip is adopted, so that the resonant chip 1 cannot collide with the support chip when vibrating in a normal use state, functional requirements such as the resonant chip 1 are met, in addition, the structural strength requirement of the support chip is also met, and the chip is prevented from deforming along with the deformation of the shell 42.

During specific implementation, 4 supporting legs 20 transversely extend from the outer side surface of the bracket body 21, and the 4 supporting legs 20 are arranged in an X shape.

In a specific manufacturing process, the supporting legs 20 may be 4 in number and arranged in an X shape. Thus, the structure is stable even if the processing is convenient. In order to further optimize the scheme of the invention, in the invention, the chip, the shell 42, the bracket (bracket body 21) and various grooves are all in a regular quadrangle shape and are concentrically arranged, the directions of the edges and the corners are the same, and the supporting legs 20 of the chip bracket 2 extend out from the directions of the edges and the corners of the regular quadrangle structure, so that the whole resonance device can be conveniently processed, designed and assembled, the space is saved to the maximum extent, and the resonance device is favorably miniaturized.

As shown in fig. 4, in a specific implementation, the fixing portion 11 of the resonant chip 1 is a ring, the inner wall of the ring fixing portion 11 extends transversely to form the resonant beam 10, the end surface of the ring fixing portion 11 matches with the ring-mounting end surface around the groove of the bracket body 21, and the end surface of the ring fixing portion 11 is attached to the ring-mounting end surface around the groove of the bracket body 21.

By the design, the limited space is reasonably used, the structural characteristics of the support body 21 are utilized to the maximum extent, so that the bonding area of the resonance chip 1 and the chip support 2 is large, and the bonding stability is ensured.

During the concrete implementation, be provided with downwardly extending's first recess on the shell 42 up end, be provided with downwardly extending's second recess on the bottom surface under the first recess, be provided with downwardly extending's integrated chip 41 mounting groove under the second recess on the bottom surface, integrated chip 41 and the bottom surface of second recess lead wire 61 electrical connection through spot welding, resonant chip 1's supporting legs 20 install on the bottom surface of first recess its lead wire 61 electrical connection through spot welding with the bottom surface of first recess.

In the invention, the inner cavity of the shell 42 is of a multi-step structure, the bonding of various parts and the spot welding of the lead 61 are carried out on the horizontal end surface, the construction difficulty is reduced, and the multi-step structure provides mounting positions with different heights for different parts, thereby realizing the reasonable utilization of space.

In specific implementation, the upper end surface of the supporting leg 20 is flush with the upper end surface of the bracket body 21, and the thickness of the supporting leg 20 is smaller than that of the bracket body 21.

In the invention, the thickness of the support body 21 is larger, so that the loss of the structural strength of the chip support 2 caused by the resonant beam groove 22 is made up, and the deformation resistance of the chip support 2 is improved.

Finally, it is noted that the above-mentioned embodiments illustrate rather than limit the invention, and that, while the invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The utility model provides a miniature three-dimensional closed assembly's MEMS resonance device, is including being equipped with open shell and the open block of sealed enclosure, its characterized in that still includes the chip support that can electrically conduct, the chip support with resonance chip thermal expansion coefficient is the same, resonance chip includes resonance roof beam and fixed part, and resonance chip passes through the fixed part and installs on the chip support and make resonance roof beam unsettled, chip support mounting on the shell inner wall and with shell electrical connection, the bottom surface is equipped with the integrated chip mounting groove in the shell of chip support below, install the integrated chip with shell electrical connection in the integrated chip mounting groove.

2. The MEMS resonator device according to claim 1, wherein the chip support comprises a support body, a resonant beam groove is formed on an end surface of the support body, the fixing portion of the resonant chip is fixedly connected to an edge of the resonant beam groove, the resonant beam of the resonant chip can freely resonate at the resonant beam groove, an outer side surface of the support body extends laterally to form a support leg, the support leg is fixedly mounted on an inner wall of the housing, and the support leg is electrically connected to the housing through a lead.

3. The miniature three-dimensional stacked MEMS resonator device of claim 2, wherein 4 supporting legs laterally extend from the outer side surface of the support body, and the 4 supporting legs are arranged in an X shape.

4. The miniature three-dimensional stacked MEMS resonator device of claim 2, wherein the fixing portion of the resonator chip is a loop, an inner wall of the loop fixing portion extends laterally to form the resonator beam, an end surface of the loop fixing portion matches with the loop end surface around the recess of the holder body, and the end surface of the loop fixing portion is attached to the loop end surface around the recess of the holder body.

5. The miniature three-dimensional stacked MEMS resonator device according to any one of claims 2 to 4, wherein a first groove extending downward is formed on the upper end surface of the housing, a second groove extending downward is formed on the lower bottom surface of the first groove, an ic mounting groove extending downward is formed on the lower bottom surface of the second groove, the ic is electrically connected to the bottom surface of the second groove by a lead wire formed by spot welding, and the supporting leg of the resonator chip is mounted on the bottom surface of the first groove and electrically connected to the bottom surface of the first groove by a lead wire formed by spot welding.

6. The miniature three-dimensional stacked MEMS resonator device of claim 5, wherein the upper end surface of the support leg is flush with the upper end surface of the support body and the thickness of the support leg is less than the thickness of the support body.