CN116097564A

CN116097564A - Quartz crystal resonator, manufacturing method thereof, oscillator and electronic equipment

Info

Publication number: CN116097564A
Application number: CN202080104149.8A
Authority: CN
Inventors: 李伟; 姚艳龙; 徐慧龙
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2023-05-09
Also published as: WO2022061514A1

Abstract

A quartz crystal resonator, a manufacturing method thereof, an oscillator and electronic equipment relate to the field of quartz crystal vibration and can reduce the size of the quartz crystal resonator. The quartz crystal resonator includes: the slide glass (1) is provided with a first metal layer (21), a quartz layer (3) and a second metal layer (22) which are sequentially arranged on the surface of the slide glass (1); the cavity (10) is arranged on one side of the quartz layer (3) away from the second metal layer (21), and at least a first metal layer (21) with partial thickness is arranged between the cavity (10) and the quartz layer (3); under the condition, the manufacturing process of MEMS can be adopted to meet the manufacturing requirement of the quartz crystal resonator with small size, and further the sealing of the quartz crystal resonator and the chip can be realized.

Description

Quartz crystal resonator, manufacturing method thereof, oscillator and electronic equipment

Technical Field

The application relates to the field of quartz crystal oscillators, in particular to a quartz crystal resonator, a manufacturing method thereof, an oscillator and electronic equipment.

Background

The quartz crystal oscillator (quartz crystal resonator) is a quartz crystal resonator made of quartz materials and is commonly called as a crystal oscillator. The quartz crystal oscillator plays a role in generating frequency, has the characteristics of stability and good anti-interference performance, and is widely applied to various electronic products, such as the clock field.

The oscillation frequency of the quartz crystal oscillator is inversely proportional to the thickness of the quartz wafer, the wafer size of the low-frequency crystal oscillator is larger, the high-frequency crystal oscillator is usually obtained by adopting a method of corroding and thinning the middle of the wafer, the wafer with the periphery as a support is thicker, and the size of the whole wafer is still larger; the quartz crystal oscillator is a piezoelectric device and is sensitive to the external environment, and the quartz crystal oscillator is packaged in a special ceramic tube shell sealing mode; based on the large size of the existing quartz crystal oscillator and the sealing form of the ceramic tube shell, the sealing with an integrated circuit cannot be realized.

With the rapid development of consumer electronics, the requirements of electronic products on the integration level of chips and systems are higher and higher, and the traditional crystal oscillator is difficult to seal with a CMOS (complementary metal oxide semiconductor ) chip, so that the further improvement of the integration level of the systems is restricted.

Disclosure of Invention

The embodiment of the application provides a quartz crystal resonator, a manufacturing method thereof, an oscillator and electronic equipment, and the size of the quartz crystal resonator can be reduced.

The present application provides a quartz crystal resonator comprising: the slide glass comprises a first metal layer, a quartz layer and a second metal layer which are sequentially arranged on the surface of the slide glass; the cavity is arranged at one side of the quartz layer, which is away from the second metal layer, and at least a first metal layer with partial thickness is arranged between the cavity and the quartz layer.

The quartz crystal resonator provided by the embodiment of the application comprises a carrier sheet and a plurality of film layers (such as a first metal layer, a quartz layer and a second metal layer) positioned on the carrier sheet, wherein the quartz layer is arranged between the two metal layers, and a cavity is arranged in the film layer at the lower side of the quartz layer, so that the quartz crystal resonator is formed; in this case, the processing conditions (up to millimeter scale and down to nanometer scale) of various devices with different sizes can be satisfied based on the MEMS manufacturing process, so for the quartz crystal resonator adopting the multiple film structures provided in the embodiment of the present application, the manufacturing of the quartz crystal resonator with small size can be realized by adopting the MEMS manufacturing process; and the quartz crystal resonator based on small size can realize the sealing of the quartz crystal resonator and a chip (such as a CMOS chip), namely, the wafer-level packaging (such as cap packaging) can be realized, so that the system space is saved, and the requirement of electronic equipment on high integration level is met.

In some possible implementations, the projection of the second metal layer onto the carrier sheet is within the projection range of the cavity onto the carrier sheet. Under the condition, the second metal layer is arranged in the cavity area in a suspended mode, so that the reflectivity of sound waves generated by vibration can be enhanced, the acoustic loss is reduced, the Q value (namely the quality factor) of the quartz crystal resonator is improved, and the performance of the quartz crystal resonator is further improved.

In some possible implementations, hollowed-out parts exposing the first metal layer are arranged in the quartz layer and the second metal layer, wherein the projection of the hollowed-out parts on the slide sheet is not overlapped with the projection of the cavity on the slide sheet; namely, the windowing area is arranged above the first metal layer, so that the electric connection requirement of the first metal layer is met, and the electric connection with an external control circuit is realized.

In some possible implementations, the carrier sheet is provided with a hollowed-out portion exposing the first metal layer, wherein a projection of the cavity on the carrier sheet does not overlap with the hollowed-out portion. Namely, the windowing area is arranged below the first metal layer, so that the electric connection requirement of the first metal layer is met, and the electric connection with an external control circuit is realized.

In some possible implementations, the slide includes: a substrate, an insulating layer; the insulating layer is positioned on the surface of the substrate, which is close to one side of the first metal layer; the first metal layer comprises an upper metal layer and a lower metal layer; the lower metal layer is adjacent to the carrier sheet relative to the upper metal layer; the cavity is located in the lower metal layer and the insulating layer, and along the thickness direction of the slide, the cavity penetrates through the lower metal layer and the insulating layer.

In some possible implementations, the slide includes: a substrate, an insulating layer; the insulating layer is positioned on the surface of the substrate, which is close to one side of the first metal layer; the cavity is located in the insulating layer.

In some possible implementations, the substrate is a silicon substrate.

In some possible implementations, the sides of the first metal layer, the quartz layer, and the second metal layer are covered with an insulating material to protect the sides of the first metal layer, the quartz layer, and the second metal layer.

The embodiment of the application also provides a manufacturing method of the quartz crystal resonator, which comprises the following steps:

sequentially forming an insulating film layer and a first metal film layer on a first substrate, and forming a groove on one side where the first metal film layer is arranged to obtain a first intermediate; and sequentially forming a quartz film layer and a second metal film layer on the second substrate to obtain a second intermediate.

And bonding the first intermediate and the second intermediate through the first metal film layer and the second metal film layer so as to form a cavity at the groove position.

And removing the second substrate and forming a third metal film layer on the surface of the quartz film layer.

Forming an isolation groove surrounding the cavity on one side where the third metal film layer is arranged; the isolation groove at least penetrates through the third metal film layer, the quartz film layer, the second metal film layer and the first metal film layer.

In summary, for the manufacturing method of the quartz crystal resonator, the whole manufacturing process can be completed by adopting the MEMS manufacturing process, that is, the requirement of the quartz crystal resonator on the size can be met as long as the manufacturing range (up to millimeter scale and down to nanometer scale) of the MEMS is within, that is, the quartz crystal resonator manufactured by adopting the manufacturing method can be ensured to meet the requirement on the small size; and the quartz crystal resonator and the chip can be sealed based on the small-size quartz crystal resonator, so that the wafer-level packaging can be realized, the system space is saved, and the requirement of electronic equipment on high integration level is met.

In some possible implementations, forming the isolation groove around the cavity on the side where the third metal film layer is disposed includes: forming a first isolation groove around the cavity on the third metal film layer; wherein the edge of the third metal film layer positioned at the inner side of the first isolation groove is positioned at the inner side of the edge of the cavity; and forming a second isolation groove penetrating through the quartz film layer, the second metal film layer and the first metal film layer at a position corresponding to the first isolation groove, wherein the edge of the quartz film layer at the inner side of the second isolation groove protrudes out of the edge of the third metal film layer positioned in the first isolation groove.

In some possible implementations, after forming the second isolation trench, further includes: forming a hollowed-out part penetrating through the quartz film layer and exposing the second metal film layer in a region, which is protruded from the third metal film layer, of the quartz film layer at the inner side of the second isolation groove; the electric connection requirement of the lower electrode (corresponding to the second metal film layer) in the quartz crystal resonator is met, and the electric connection with an external control circuit is realized.

Embodiments of the present application also provide an oscillator including a package substrate, and a chip (e.g., a CMOS chip) disposed on the package substrate, and a quartz crystal resonator as provided in any one of the foregoing possible implementations; the chip is connected with the quartz crystal resonator.

The embodiment of the application also provides electronic equipment, which comprises a printed circuit board and the quartz crystal resonator which is connected with the printed circuit board and provided in any one of the possible implementation modes.

Drawings

FIG. 1 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 2a is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 2b is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 5a is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 5b is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 6a is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 6b is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 8 is a flowchart of a method for fabricating a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 10 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 11 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 12 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

FIG. 13 is a schematic diagram of a quartz crystal resonator according to an embodiment of the present disclosure;

fig. 14 is a schematic structural diagram of a quartz crystal resonator according to an embodiment of the present application.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions in the present application will be clearly described below with reference to the drawings in the present application, and it is apparent that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

The terms "first," "second," and the like in the description and in the claims and drawings are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or order. "at least one" means one or more, and "a plurality" means two or more. "connected," "coupled," and the like, are used to indicate interworking or interaction between different components, and may include direct coupling or indirect coupling via other components. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion, such as a series of steps or elements. The method, article, or apparatus is not necessarily limited to those explicitly listed but may include other steps not explicitly listed or inherent to such process, method, article, or apparatus. "upper", "lower", "left", "right", etc. are used merely with respect to the orientation of the components in the drawings, these directional terms are relative terms, which are used for description and clarity with respect thereto, and which may vary accordingly depending on the orientation in which the components are placed in the drawings.

The embodiment of the application provides an electronic device, in which a quartz crystal oscillator (also simply called an oscillator) and other electronic devices connected with the quartz crystal oscillator are arranged, such as a printed circuit board (printed circuit board, PCB) and the like; the specific setting form of the electronic device is not limited, and for example, the electronic device can be an electronic product such as a mobile phone, a tablet computer, a notebook computer, a smart watch, a Bluetooth headset and the like.

In the quartz crystal oscillator in the electronic device, the quartz crystal resonator (hereinafter may also be simply referred to as a quartz crystal oscillator) and a chip (for example, a CMOS chip, but not limited thereto) are sealed, that is, in the quartz crystal oscillator, the chip and the quartz crystal resonator connected with the chip are arranged on the same packaging substrate for packaging, so that the system space can be reduced, and the requirement of the electronic device on high integration level can be met; the following examples are given by taking the case of sealing a quartz crystal resonator and a CMOS chip.

In the resonator of the present application, the quartz crystal resonator and the CMOS chip may be stacked on the package substrate, or may be disposed in parallel on the package substrate, which is not limited in this application. The connection modes such as wire bonding (wire bonding), protruding points (bump) and the like can be adopted between the quartz crystal resonator and the CMOS chip and between the quartz crystal resonator and the packaging substrate, and the quartz crystal resonator is not limited in the application, and can be selected and arranged according to the needs in practice.

In some possible implementations, a quartz crystal oscillator may be integrated in a system in package (system in package, SIP) to achieve the electronic device's demands for high integration, high performance, low power consumption, low cost, etc.

In addition, for the oscillator of the present application, the quartz crystal resonator and the CMOS chip are directly sealed, and the size of the quartz crystal resonator is necessarily required to be small enough to meet the sealing requirement of the quartz crystal resonator and the CMOS chip, and the embodiments of the present application provide a small-sized quartz crystal resonator that can be manufactured based on the MEMS (microelectromechanical systems, microelectromechanical system) manufacturing process (may also be referred to as micro-nano manufacturing process, microfabrication process), and a specific arrangement of the quartz crystal resonator is described below.

Those skilled in the art will appreciate that the MEMS fabrication process is a down to nanometer scale and up to millimeter scale micro-structure fabrication process that can accommodate the fabrication of a variety of different size devices, and that MEMS fabrication processes include, but are not limited to, photolithography, epitaxy, thin film deposition, oxidation, diffusion, implantation, sputtering, evaporation, etching, dicing, and packaging, among others, are basic processes.

The embodiment of the present application provides a quartz crystal resonator, as shown in fig. 1 and fig. 2a, the quartz crystal resonator includes a carrier 1, and a first metal layer 21, a quartz layer 3, and a second metal layer 22 sequentially disposed on the surface of the carrier 1, and a cavity 10 is disposed on the lower side of the quartz layer 3 (i.e. the side facing away from the second metal layer 22), where at least a portion of the first metal layer 21 with a thickness is disposed between the cavity 10 and the quartz layer 3, that is, at least a portion of the first metal layer 21 is remained on the lower surface of the quartz layer 3 corresponding to the position of the cavity 10, so as to ensure that the metal layers disposed on the upper and lower surfaces of the quartz layer 3 can be used as upper and lower electrodes, so that when an electrical signal is applied to the two electrodes, the quartz layer located in the cavity region can generate mechanical vibration, thereby generating piezoelectric resonance.

For the first metal layer 21 described above, which has at least a partial thickness between the cavity 10 and the quartz layer 3:

in some possible implementations, as shown in fig. 1, it may be that the cavity 10 is located in the first metal layer 21, but does not completely penetrate the first metal layer 21 on the side close to the quartz layer 3, i.e. only a partial thickness of the first metal layer 21 remains between the quartz layer 3 and the cavity 10.

In some possible implementations, as shown in fig. 2a, the cavity 10 may be located in the carrier sheet 1 on the underside of the first metal layer 21 (i.e. the side facing away from the quartz layer 3), i.e. the entire thickness of the first metal layer 21 remains between the quartz layer 3 and the cavity 10.

It should be noted here that, in some possible implementations, as shown in fig. 1 and 2a, a cavity 10 may be provided in the quartz crystal resonator of the present application; in some possible implementations, as shown in fig. 2b, two or more cavities 10 may be provided in the quartz crystal resonator; the present application does not limit this, and in practice, the setting may be selected as needed. The following embodiments will each be described schematically by taking as an example a quartz crystal resonator in which a cavity 10 is provided.

The location of the cavity 10 is further described below in connection with the specific placement of the first metal layer 21 and the carrier sheet 1.

As shown in fig. 3, in some possible implementations, the carrier sheet 1 includes a substrate 11 and an insulating layer 12; the first metal layer 21 includes a lower metal layer 211 and an upper metal layer 212; the insulating layer 12, the lower metal layer 211, and the upper metal layer 212 are sequentially stacked on the surface of the substrate 11; that is, the insulating layer 12 is located on the surface of the substrate 11 on the side close to the first metal layer 21, and the upper metal layer 212 in the first metal layer 21 is located on the side of the lower metal layer 211 facing away from the insulating layer 12.

In this case, as shown in fig. 3, the cavity 10 may be disposed in the lower metal layer 211 and the insulating layer 12, and considering the actual fabrication process and the thickness requirement of the quartz crystal resonator, the cavity 10 may be disposed through the lower metal layer 211 and the insulating layer 12, and the specific fabrication method of the cavity 10 may refer to the fabrication method provided in the related embodiments below, which will not be described herein.

As shown in fig. 4, in some possible implementations, the carrier sheet 1 includes a substrate 11 and an insulating layer 12, the first metal layer 21 is disposed on an upper surface of the insulating layer 12 (i.e., a surface facing away from the substrate 11), and the cavity 10 is located in the insulating layer 12.

In some possible implementations, the substrate 11 may be a glass sheet (i.e., a glass substrate), a silicon wafer (i.e., a Si substrate, a Si wafer), or other sheet that has similar functionality and is compatible with wafer level packaging process materials.

In some possible implementations, the insulating layer 12 may be made of silicon oxide (SiO ₂ ) Silicon nitride (SiN) _x ) Silicon oxynitride (SiO) _x N _y ) One or more of the following.

In some possible implementations, any of the foregoing metal layers (e.g., 21, 22, 211, 212) may be one or more of molybdenum (Mo), aluminum (Al), and copper (Cu), and the metal layer may be a single-layer metal layer formed of one metal, or may be a multi-layer metal composite layer formed of multiple metals.

On this basis, in some possible implementations, as shown in fig. 5a, the area of the second metal layer 22 may be reduced, the edge of the second metal layer 22 is disposed inside the edge of the cavity 10, and the outer edge of the quartz layer 3 protrudes from the outer edge of the second metal layer 22, that is, the projection of the second metal layer 22 on the slide 1 is within the range of the projection of the cavity 10 on the slide 1; in this way, the second metal layer 22 is suspended in the cavity 10, so as to enhance the reflectivity of the acoustic wave generated by vibration, reduce the acoustic loss, and improve the Q value (i.e. quality factor) of the quartz crystal resonator, thereby improving the performance of the quartz crystal resonator. It is understood that the above projection of the cavity 10 onto the slide 1 refers to the projection of the cavity region of the cavity 10 (or the region surrounded by the cavity side walls) onto the slide 1; the term "projection of the cavity 10 onto the slide 1" will be understood in this regard and will not be described in detail.

It should be noted here that, in the case of the above-mentioned arrangement in which the edge of the second metal layer 22 is located inside the edge of the cavity 10, in some possible implementations, as shown in fig. 5a, the edge of the quartz layer 3 may be located outside the edge of the cavity 10, i.e. the projection of the quartz layer 3 onto the slide 1 covers the projection of the cavity 10 onto the slide 1; in some possible implementations, as shown in fig. 5b, the edge of the quartz layer 3 may also be located outside the edge of the cavity 10, i.e. the projection of the quartz layer 3 onto the slide 1 is within the projection range of the cavity 10 onto the slide 1; the present application is not limited in this regard. Of course, in view of reliability (e.g., aging, etc.) of the first metal layer 21 under the quartz layer 3, it is generally possible to provide that the edge of the quartz layer 3 is located outside the edge of the cavity 10.

In addition, since the first metal layer 21 (i.e., the lower electrode) is located at the lower side of the quartz layer 3, in order to facilitate the normal electrical connection between the first metal layer 21 and an external control circuit (such as a CMOS chip), a window (i.e., a hollowed-out portion) may be formed above or below the first metal layer 21 to expose a portion of the first metal layer 21, so as to meet the electrical connection requirement of the first metal layer 21; for example, the first metal layer 21 may be electrically connected (directly connected or indirectly connected) to the CMOS chip by wire bonding (wire bonding), bump (bump), or the like at the position of the hollowed-out portion.

Schematically, as shown in fig. 6a, in some possible implementations, a hollowed-out portion S may be provided in the quartz layer 3 and the second metal layer 22, where the hollowed-out portion S is located in an outer area of the cavity 10; that is, the projection of the hollowed-out portion S on the carrier 1 and the projection of the cavity 10 on the carrier 1 do not overlap, so that the first metal layer 21 is exposed through the hollowed-out portion S.

As shown schematically in fig. 6b, in some possible implementations, a hollowed-out portion S may be provided on the slide 1 in an area outside the cavity 10, that is, the projection of the cavity 10 on the slide 1 does not overlap with the hollowed-out portion S, so as to expose the first metal layer 21 through the hollowed-out portion S.

In addition, as shown in fig. 7, in some possible implementations, the insulating layer 4 may be provided on the side surfaces of the first metal layer 21, the quartz layer 3, and the second metal layer 22, or the side surfaces of the first metal layer 21, the quartz layer 3, and the second metal layer 22 may be covered with an insulating material to protect the side surfaces of the first metal layer 21, the quartz layer 3, and the second metal layer 22.

The embodiment of the present application further provides a method for manufacturing a quartz crystal resonator, taking the quartz crystal resonator shown in fig. 6a as an example, as shown in fig. 8, where the manufacturing method includes:

step 01, referring to fig. 9 (a), an insulating film layer D and a first metal film layer M1 are sequentially formed on a first substrate 100; referring to fig. 9 (b), a groove C is formed at a side where the first metal film layer M1 is disposed, to obtain a first intermediate A1. Referring to fig. 10, a quartz film layer Q and a second metal film layer M2 are sequentially formed on a second substrate 200 to obtain a second intermediate A2.

It should be noted that, when the groove C is formed on the side where the first metal film layer M1 is disposed, the groove C may be located in the first metal film layer M1, or may penetrate through the first metal film layer M1, and be partially located in the insulating film layer D; of course, in practice, in order to reduce the thickness of the quartz crystal resonator as much as possible, it is generally possible to provide the grooves C penetrating the insulating film layer D and the first metal film layer M1.

Illustratively, for the preparation of the first intermediate A1 in step 01, referring to (a) and (b) in fig. 9, it may include: growth of SiO on Si wafer (100) ₂ Film layer (D) of SiO ₂ A Mo metal film layer (M1) with the thickness of 300nm is deposited on the surface of the film layer (D); and a recess C is formed on the first metal film layer M1 and the insulating film layer D using a reactive ion etching process (reactive ion etch, RIE) to form a first intermediate A1 (which may also be referred to as host wafer).

Illustratively, for the production of the second intermediate A2 in step 01, referring to fig. 10, it may include: the quartz wafer (Q) is bonded to the surface of the Si wafer (200), and then a Mo metal film layer (M1) with the thickness of 300nm is evaporated on the surface of one side of the quartz wafer (Q) facing away from the Si wafer (200) to form a second intermediate A2 (also called as a handling wafer).

It should be noted that, in step 01, the formation of the groove C on the side where the first metal film layer M1 is disposed may be a formation of a plurality of grooves C, so that a plurality of quartz crystal resonators can be formed by a single process and then by dicing; the corresponding relevant drawings in the manufacturing method of the present application are only schematic and illustrate one quartz crystal resonator.

Step 02, referring to fig. 11, the first intermediate A1 and the second intermediate A2 are bonded through the first metal film M1 and the second metal film M2 to form a cavity 10 at the position of the groove C.

Illustratively, for the foregoing formation of the host wafer (A1) and the handling wafer (A2), referring to fig. 10, the host wafer (A1) and the handling wafer (A2) may be bonded through two Mo metal film layers (M1, M2), so that the cavity 10 is formed at the groove C position of the host wafer (A1), that is, a wafer (wafer) with the cavity 10 is formed.

Step 03, referring to fig. 11 to 12 (a), the second substrate 200 is removed, referring to fig. 12 (b), and a third metal film M3 is formed on the surface of the quartz film Q.

Illustratively, on the basis of the foregoing formation of a wafer with a cavity 10, referring to fig. 11 to 12 (a), the Si wafer (200) in the handling wafer (A2) may be removed by using a chemical mechanical polishing process (chemical mechanical polishing, CMP), while the quartz wafer (Q) may be thinned appropriately (for example, to below 100 μm), and then the thickness of the quartz wafer (Q) may be corrected by using a plasma trimming (trimming) process, so that the thickness fluctuation of the quartz wafer (Q) is ensured to be less than 1%. Next, referring to fig. 12 (b), a Mo metal film layer (M3) having a thickness of 300nm was deposited on the surface of the trimmed quartz wafer (Q).

Step 04, referring to fig. 13 (b), forming an isolation groove P around the cavity 10 on the side where the third metal film layer M3 is disposed; the isolation groove P at least penetrates through the third metal film M3, the quartz film Q, the second metal film M2 and the first metal film M1.

In practice, in order to improve the Q value of the quartz crystal resonator, the edge of the third metal film layer M3 located in the isolation groove P may be located at the inner side of the edge of the cavity 10, so as to enhance the reflectivity of the acoustic wave generated by the vibration, reduce the acoustic loss, and improve the performance of the quartz crystal resonator.

Based on this, the above step 04 may include: referring to fig. 13 (a), a first isolation groove P1 disposed around the cavity 10 may be formed in the third metal film layer M3 by a single etching process; wherein, the edge of the third metal film layer M3 located inside the first isolation groove P1 is located inside the cavity 10 area; referring to fig. 13 (b), a second isolation groove P2 penetrating through the quartz film layer Q, the second metal film layer M2, and the first metal film layer M1 is then formed at a position corresponding to the first isolation groove P1 by a single etching process; the width of the second isolation groove P1 is smaller than that of the second isolation groove P2, and the edge of the quartz film layer Q inside the second isolation groove P2 protrudes out of the edge of the third metal film layer M3 inside the first isolation groove P1.

The etching process referred to in the application may be a wet etching process or a dry etching process (such as a reactive ion etching process), and may specifically be a suitable etching process selected according to a film layer to be etched, which is not limited in the application; for example, for the etching process adopted to form the second isolation groove P2, a hydrofluoric acid wet etching may be adopted, so as to ensure that metal and quartz can be etched at the same time.

It should be further noted that, in step 04, in the case where the isolation groove P surrounding the cavity 10 is formed on the side where the third metal film layer M3 is provided, in the case where the cavity 10 in the quartz crystal resonator to be formed is one, the isolation groove P is provided around one cavity 10, and in the case where the cavity 10 in the quartz crystal resonator to be formed is plural (i.e., two or more, refer to fig. 2 b), the isolation groove P is provided around plural cavities 10.

Referring to fig. 13 (b), it will be understood by those skilled in the art that a plurality of individual quartz crystal resonators may be formed by cutting along the position of the isolation groove P later, that is, the portion located inside the isolation groove P later acts as a quartz crystal resonator; it can be understood that, in the inner region of the isolation groove P, the third metal film layer M3 and the second metal film layer M2 (or the first metal film layer M1) are respectively used as the upper electrode and the lower electrode of the quartz film layer Q, so that in order to facilitate the normal electrical connection between the second metal film layer M2 and the external control circuit, a window (i.e. a hollowed-out portion) may be generally formed above or below the second metal film layer M2 to expose the second metal film layer M2, so as to meet the electrical connection requirement of the second metal film layer M2.

Based on this, in some possible implementations, as shown in fig. 14, after the second isolation trench P2 is formed, a hollowed-out portion S (i.e. the aforementioned window) penetrating through the quartz film layer Q may be formed in a region where the quartz film layer Q inside the second isolation trench P2 protrudes from the third metal film layer M3, so as to expose the second metal film layer M, and ensure the electrical connection of the lower electrode (the second metal film layer M2).

Of course, in other implementations, a hollowed-out portion S (schematically shown in fig. 6 b) penetrating the first substrate 100 and the insulating film layer D and exposing the lower surface of the first metal film layer M1 (i.e., the surface on the side facing away from the second metal film layer M2) may be formed on the back surface of the first substrate 100 (also facing away from the cavity 10) and in the area between the cavity 10 and the isolation groove P, so as to ensure electrical connection of the lower electrode (the first metal film layer M1).

After the relevant fabrication process is completed, a plurality of individual quartz crystal resonators are formed by dicing along the positions of the isolation trenches P (as shown in fig. 6 a).

In addition, according to practical needs and application of the quartz crystal resonator, in some possible implementation manners, after the isolation trench P as shown in fig. 13 (b) is fabricated, an insulating material (such as SiO ₂ ) In this case, the quartz crystal resonator formed separately after dicing is covered with an insulating material on each of the metal layers and the side surfaces of the quartz layer (see fig. 7), thereby forming a protective layer on the side surfaces of the quartz crystal resonator.

Furthermore, in some possible implementations, in order to isolate the crystal oscillator surface in the quartz crystal resonator from the external environment, the quartz crystal resonator may be packaged using a packaging process (e.g., cap packaging).

Illustratively, as another possible manufacturing process, compared to the aforementioned manufacturing method (steps 01 to 04), when the first intermediate A1 is manufactured in the aforementioned step 01, the process of manufacturing the first metal film M1 may be omitted, and the groove C may be directly formed on the insulating film D; in this case, the insulating film layer D and the second intermediate A2 may be bonded by an adhesive; for other fabrication steps, reference may be made to the remaining fabrication steps described above, and no further description is given here.

In summary, for the manufacturing method of the quartz crystal resonator, the whole manufacturing process can be completed by adopting the MEMS manufacturing process, that is, the requirement of the quartz crystal resonator on the size can be met as long as the manufacturing range of the MEMS is within, that is, the quartz crystal resonator manufactured by adopting the manufacturing method can be ensured to meet the requirement on the small size, so that the quartz crystal resonator and the CMOS chip can be sealed together, the wafer-level packaging can be achieved, the system space can be saved, and the requirement of the electronic device on the high integration degree can be met.

Regarding the fabrication of the quartz crystal resonator with other structures, the above fabrication method may be referred to and combined with the related fabrication process, and an appropriate fabrication method may be selected, which is not described herein.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A quartz crystal resonator, comprising:

the slide glass comprises a slide glass body, a first metal layer, a quartz layer and a second metal layer, wherein the first metal layer, the quartz layer and the second metal layer are sequentially arranged on the surface of the slide glass body;

the cavity is arranged at one side of the quartz layer, which is away from the second metal layer, and at least a first metal layer with partial thickness is arranged between the cavity and the quartz layer.
The quartz crystal resonator of claim 1, wherein the quartz crystal resonator is configured to,

the projection of the second metal layer on the slide is positioned within the projection range of the cavity on the slide.
A quartz crystal resonator according to claim 1 or 2,

the quartz layer and the second metal layer are provided with hollowed-out parts exposing the first metal layer, and the projection of the hollowed-out parts on the slide sheet is not overlapped with the projection of the cavity on the slide sheet.
A quartz crystal resonator according to claim 1 or 2,

the slide is provided with a hollowed-out part exposing the first metal layer; the projection of the cavity on the slide glass is not overlapped with the hollowed-out part.
A quartz crystal resonator as in any of claims 1-4,

the slide includes: a substrate, an insulating layer; the insulating layer is positioned on the surface of the substrate, which is close to one side of the first metal layer;

the first metal layer comprises an upper metal layer and a lower metal layer; the lower metal layer is adjacent to the carrier sheet relative to the upper metal layer;

the cavity is located in the lower metal layer and the insulating layer, and along the thickness direction of the slide, the cavity penetrates through the lower metal layer and the insulating layer.
A quartz crystal resonator as in any of claims 1-4,

the slide includes: a substrate, an insulating layer;

the insulating layer is positioned on the surface of the substrate, which is close to one side of the first metal layer;

the cavity is located in the insulating layer.
The quartz-crystal resonator of any of claims 1-6, wherein sides of the first metal layer, the quartz layer, the second metal layer are covered with an insulating material.
A method of making a quartz crystal resonator, comprising:

sequentially forming an insulating film layer and a first metal film layer on a first substrate, and forming a groove on one side where the first metal film layer is arranged to obtain a first intermediate; sequentially forming a quartz film layer and a second metal film layer on a second substrate to obtain a second intermediate;

bonding the first intermediate and the second intermediate through the first metal film layer and the second metal film layer to form a cavity at the groove position;

removing the second substrate, and forming a third metal film layer on the surface of the quartz film layer;

forming an isolation groove surrounding the cavity on one side where the third metal film layer is arranged; the isolation groove at least penetrates through the third metal film layer, the quartz film layer, the second metal film layer and the first metal film layer.
The method of claim 8, wherein forming an isolation trench around the cavity on the side where the third metal film layer is disposed comprises:

forming a first isolation groove around the cavity on the third metal film layer; wherein the edge of the third metal film layer positioned at the inner side of the first isolation groove is positioned at the inner side of the edge of the cavity;

and forming a second isolation groove penetrating through the quartz film layer, the second metal film layer and the first metal film layer at a position corresponding to the first isolation groove, wherein the edge of the quartz film layer at the inner side of the second isolation groove protrudes out of the edge of the third metal film layer positioned in the first isolation groove.
The method of manufacturing a quartz crystal resonator according to claim 9, wherein,

the manufacturing method of the quartz crystal resonator further comprises the following steps of after the second isolation groove is formed:

and forming a hollowed-out part penetrating through the quartz film layer and exposing the second metal film layer in a region, which is protruded from the third metal film layer, of the quartz film layer at the inner side of the second isolation groove.
An oscillator comprising a package substrate and a chip provided on the package substrate and the quartz crystal resonator according to any of claims 1-7;

the chip is connected with the quartz crystal resonator.
An electronic device comprising a printed circuit board and the quartz crystal resonator of any of claims 1-7 coupled to the printed circuit board.