A full quartz resonant force sensor chip structure

Abstract

The utility model relates to a full quartz resonant force sensor chip structure, including a quartz upper cover, a quartz frequency chip and a quartz base, a concave or convex MESA structure is arranged on the quartz frequency chip, a quartz upper cover is installed on the upper end of the quartz frequency chip, the quartz upper cover forms a sealed space outside the MESA structure, an electrode surface is arranged on the MESA structure, electrodes connected to the electrode surface are arranged on both sides of the quartz frequency chip, the quartz frequency chip is installed on the quartz base, a pad is arranged on both sides of the upper end of the quartz base, and each pad is connected to the corresponding electrode. The utility model stacks the quartz upper cover, the quartz frequency chip and the quartz base to form a mechanical sensitive unit, and the entire mechanical sensitive unit adopts a consistent quartz material. Such a combined structure can reduce the loss of force transmission during the sensing process, ensure the force transmission effect, and improve the accuracy of the force sensing signal.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical sensors, in particular to a full quartz resonant force sensor chip structure. Background Art

[0002] Traditional mechanical sensors usually use strain gauges as sensitive units. They use metal materials as the deformation body and measure the resistance change generated as the sensor variable. However, due to their large deformation size, they lack miniaturization and multifunctionality and cannot be combined with other electronic components. Therefore, better alternatives need to be found in terms of miniaturization. In order to solve this problem, new materials and micro-electromechanical systems (MEMS) manufacturing processes have been proposed. The MEMS process, which uses semiconductor materials as the mainstream, can manufacture a variety of miniaturized sensors and combine them with IC chips to form multifunctional products.

[0003] Using quartz piezoelectric resonant components (QCRs) as the sensitive unit of mechanical sensors, instead of detecting the change in resistance, directly detects the change in its vibration frequency, which can present functions with advantages such as high sensitivity, high precision and fast response, and can be manufactured in the MEMS way, which has advantages in miniaturization and multi-function. The sensitive units of early quartz piezoelectric resonant sensors were all disc-shaped, and resonated using the AT-cut thick film shear oscillation method. There have been a large number of papers on the research of bare chips (without electrodes). Because the rigidity of the sensitive unit is closely related to the vibration frequency, when an external force is applied to the crystal, its bearing capacity will affect its range, so the research on the force-frequency coefficient is the key factor. At the same time, in consideration of subsequent multi-functions, mechanical properties and processing, square structures have also begun to be used in sensor sensitive units. However, because the sensitive unit chip is a thin sheet structure, it is easy to break and has insufficient bearing capacity, resulting in insufficient range. Therefore, how to increase its mechanical strength and increase its range without affecting its sensing frequency accuracy and other functions. Summary of the invention

[0004] The technical problem to be solved by the utility model is to provide a full quartz resonant force sensor chip structure. The quartz upper cover, quartz frequency chip and quartz base are stacked together to form a mechanical sensitive unit. The entire mechanical sensitive unit adopts a consistent quartz material. Such a combined structure can reduce the loss of force transmission during the sensing process, ensure the force transmission effect, improve the accuracy of the force sensing signal, and has a relatively strong force-bearing capacity and is not easy to break.

[0005] The utility model solves the technical problem by adopting the following technical solution: providing a full quartz resonant force sensor chip structure, comprising a quartz upper cover, a quartz frequency chip and a quartz base, wherein a concave or convex MESA structure is arranged on the quartz frequency chip, a quartz upper cover is installed on the upper end of the quartz frequency chip, the quartz upper cover is covered outside the MESA structure, so that a sealed space is formed above the MESA structure, an electrode surface is arranged on the upper end of the MESA structure, electrodes connected to the electrode surface are arranged on both sides of the quartz frequency chip, the quartz frequency chip is installed on the quartz base, the lower part of the MESA structure is sealed by the quartz base to form a sealed space, a welding pad is arranged on both sides of the upper end of the quartz base, and each welding pad is connected to a corresponding electrode.

[0006] As a supplement to the technical solution described in the utility model, the resonant frequency of the quartz frequency chip ranges from 20 to 300 MHz.

[0007] As a supplement to the technical solution of the present invention, the thickness of the MESA structure is T, and the range of T is between 5 and 100 microns.

[0008] As a supplement to the technical solution described in the utility model, stress concentration structures are provided on both the front and rear sides of the quartz frequency chip, and the stress concentration structures are stress grooves; the shape of the stress grooves is an isosceles trapezoid.

[0009] As a supplement to the technical solution of the utility model, the quartz upper cover and the quartz frequency chip are fixed by bonding with a sealant or by metal welding.

[0010] As a supplement to the technical solution of the utility model, the quartz frequency chip and the quartz base are fixed by bonding with sealant or by metal welding.

[0011] As a supplement to the technical solution described in the utility model, a welding metal layer is installed on the inner side of each welding pad at the upper end of the quartz base, and the two welding metal layers are respectively welded and fixed to the two sides of the lower end of the quartz frequency chip.

[0012] Beneficial effects: The utility model relates to a full quartz resonant force sensor chip structure, in which a quartz upper cover, a quartz frequency chip and a quartz base are stacked together to form a mechanical sensitive unit. The entire mechanical sensitive unit is made of a consistent quartz material. Such a combined structure can reduce the loss of force transmission during the sensing process, ensure the force transmission effect, improve the accuracy of the force sensing signal, and have a relatively strong force bearing capacity and are not easy to break; at the same time, without affecting the accuracy of its sensing frequency and other functions, the mechanical strength and range of the mechanical sensitive unit structure are increased. In addition to improving the range of its chip, the utility model can also increase its oscillation frequency to a high frequency range, while increasing parameters such as resolution, sensitivity, and response time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an exploded view of the utility model;

[0014] Figure 2 It is a cross-sectional view of the utility model.

[0015] Illustration: 101, quartz upper cover, 102, quartz frequency chip, 103, MESA structure, 104, electrode, 105, electrode surface, 106, stress concentration structure, 107, quartz base, 108, welding pad, 109, welding metal layer. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0017] The embodiment of the utility model relates to a full quartz resonant force sensor chip structure, such as Figure 1-2As shown, it includes a quartz cover 101, a quartz frequency chip 102 and a quartz base 107. The quartz frequency chip 102 is provided with a concave or convex MESA structure 103. The oscillation frequency of the MESA structure 103 is not affected by the change of the surrounding structure, which can increase the rigidity of the overall structure and expand the measurement range. The quartz cover 101 is installed on the upper end of the quartz frequency chip 102. The quartz cover 101 is covered outside the MESA structure 103, so that a sealed space is formed above the MESA structure 103. 3 domains are encapsulated inside, which can reduce external pollution and interference and ensure the long-term stability of the resonant frequency. The upper end of the MESA structure 103 is provided with an electrode surface 105, and both sides of the quartz frequency chip 102 are provided with electrodes 104 connected to the electrode surface 105. The quartz frequency chip 102 is installed on a quartz base 107, and the bottom of the MESA structure 103 is sealed by the quartz base 107 to form a sealed space. Both sides of the upper end of the quartz base 107 are provided with a pad 108, and each pad 108 is connected to the corresponding electrode 104.

[0018] The utility model stacks the quartz cover 101, the quartz frequency chip 102 and the quartz base 107 to form a mechanical sensing unit. The entire mechanical sensing unit is made of the same quartz material. Such a structure can reduce the loss of force transmission during the sensing process, ensure the force transmission effect, and improve the accuracy of the force sensing signal. The frequency change generated by the quartz frequency chip 102 is transmitted to the electrode 104 outside the chip by an electrical signal, and then transmitted to the signal processing center through the pad 108 and the lead wire, and the correct value can be calculated.

[0019] The resonant frequency of the quartz frequency chip 102 ranges from 20 to 300 MHz.

[0020] The thickness of the MESA structure 103 is T, and the range of T is between 5 and 100 microns; the value of the thickness dimension T determines the chip oscillation frequency range. When T<50um is thin, the oscillation is in the high frequency range and can reach above 100MHz. For traditional quartz resonant chips, T>50um, and the oscillation frequency is in the range of tens of KHz to 100MHz. When it is applied to sensors, such as mechanical sensors, it affects physical parameters such as resolution, sensitivity, response time and load-bearing range.

[0021] The front and rear sides of the quartz frequency chip 102 are both provided with stress concentration structures 106, which can significantly improve the sensitivity of the force sensing signal. The stress concentration structure 106 is a stress groove; the shape of the stress groove is an isosceles trapezoid, and this shape of stress groove can greatly improve the sensitivity. As a preferred solution, two stress grooves are respectively provided on the front and rear sides of the quartz frequency chip 102, and the stress grooves are arranged symmetrically front and back.

[0022] The quartz upper cover 101 and the quartz frequency chip 102 are fixed by adhesive bonding or metal welding.

[0023] The quartz frequency chip 102 and the quartz base 107 are fixed by sealing adhesive or metal welding; one welding fixing scheme is as follows: a welding metal layer 109 is installed on the inner side of each welding pad 108 at the upper end of the quartz base 107, and the two welding metal layers 109 are respectively welded and fixed to the two sides of the lower end of the quartz frequency chip 102.

[0024] In addition to improving the chip measurement range, the utility model can also increase the oscillation frequency to a high frequency range (>100MHz), while increasing parameters such as resolution, sensitivity, and response time.

[0025] like Figure 2 As shown, as a preferred solution of the utility model, a MESA structure 103 with recessed upper and lower ends is provided on the quartz frequency chip 102, the quartz upper cover 101 seals the upper part of the MESA structure 103 to form a sealed space, and the lower part 103 of the MESA structure is sealed by the quartz base 107 to form a sealed space; when the MESA structure 103 is a convex structure, the quartz base 107 and / or the quartz upper cover 101 are provided with a recessed structure for accommodating the convex structure.

[0026] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0027] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0028] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.

[0029] The above is a detailed introduction to the all-quartz resonant force sensor chip structure provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technicians in this field, according to the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A full quartz resonant force sensor chip structure, characterized in that: The invention comprises a quartz upper cover (101), a quartz frequency chip (102) and a quartz base (107), wherein a concave or convex MESA structure (103) is arranged on the quartz frequency chip (102), and a quartz upper cover (101) is installed on the upper end of the quartz frequency chip (102), and the quartz upper cover (101) is covered outside the MESA structure (103), so that a sealed space is formed above the MESA structure (103), and a concave or convex MESA structure (103) is arranged on the upper end of the MESA structure (103). The quartz frequency chip (102) is provided with electrodes (104) connected to the electrode surface (105) on both sides. The quartz frequency chip (102) is mounted on a quartz base (107). The quartz base (107) seals the bottom of the MESA structure (103) to form a sealed space. A soldering pad (108) is provided on both sides of the upper end of the quartz base (107). Each soldering pad (108) is connected to a corresponding electrode (104).

2. The all-quartz resonant force sensor chip structure according to claim 1, characterized in that: The resonance frequency of the quartz frequency chip (102) ranges from 20 to 300 MHz.

3. The all-quartz resonant force sensor chip structure according to claim 1, characterized in that: The thickness of the MESA structure (103) is T, and the range of T is between 5 and 100 microns.

4. The all-quartz resonant force sensor chip structure according to claim 1, characterized in that: The front and rear sides of the quartz frequency chip (102) are both provided with stress concentration structures (106), and the stress concentration structures (106) are stress grooves.

5. The all-quartz resonant force sensor chip structure according to claim 4, characterized in that: The shape of the stress groove is an isosceles trapezoid.

6. The all-quartz resonant force sensor chip structure according to claim 1, characterized in that: The quartz upper cover (101) and the quartz frequency chip (102) are fixed by bonding with a sealant or by metal welding.

7. The all-quartz resonant force sensor chip structure according to claim 1, characterized in that: The quartz frequency chip (102) and the quartz base (107) are fixed by bonding with a sealant or by metal welding.

8. The all-quartz resonant force sensor chip structure according to claim 7, characterized in that: A welding metal layer (109) is installed on the inner side of each welding pad (108) at the upper end of the quartz base (107), and the two welding metal layers (109) are respectively welded and fixed to the two sides of the lower end of the quartz frequency chip (102).

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