Hemispherical shell manufacturing method and hemispherical resonant gyroscope

Abstract

The invention provides a hemispherical shell manufacturing method and a hemispherical resonant gyroscope, and relates to the technical field of manufacturing of micro electro mechanical systems and inertial devices. The method comprises the following steps: forming an annular groove in the upper surface of an SOI silicon wafer, and forming a silicon dioxide protection layer covering the annular groove; a glass substrate is used for sealing the annular groove to form a sealing cavity, a first area of the glass substrate is etched to form a separation groove, and the first area surrounds the sealing cavity; and heating the glass to form a hemispherical shell. According to the embodiment of the invention, wafer-level manufacturing of the hemispherical shell can be realized, the processing link and the processing time are shortened, the manufacturing cost is effectively reduced, the batch consistency is improved, and large-scale application is facilitated.

Description

Technical Field

[0001] This application relates to the field of microelectromechanical systems (MEMS) and inertial device manufacturing technology. Specifically, this application relates to a method for manufacturing a hemispherical shell and a hemispherical resonant gyroscope. Background Technology

[0002] Hemispherical resonator gyroscopes are core sensors in inertial navigation devices and related measurement and control systems, widely used in aviation, aerospace, maritime, rail transportation, and many other fields. As a novel all-solid-state gyroscope, the hemispherical resonator gyroscope boasts advantages such as high precision, low noise, large dynamic range, long lifespan, and high reliability. It also features long-term stable scaling factor, accuracy unaffected by size, and performance retention even when powered off, making it considered a "preferred sensor for high-value missions" with enormous future application potential.

[0003] Hemispherical resonator gyroscopes typically rely on a hemispherical shell with high symmetry, good surface quality, and strong stability to achieve high-precision data acquisition. However, existing methods for manufacturing hemispherical shells often involve precision machining, shaping, and polishing, which frequently result in numerous processing steps, long processing times, high manufacturing costs, and difficulties in maintaining batch consistency, thus hindering large-scale applications and cost reduction. Summary of the Invention

[0004] This application provides a method for manufacturing a hemispherical shell and a hemispherical resonant gyroscope, which can solve the problems of multiple processing steps, long processing time, high manufacturing cost, and difficulty in ensuring batch consistency in the existing hemispherical shell manufacturing process. To achieve this objective, this application provides the following solutions.

[0005] According to one aspect of the embodiments of this application, a method for manufacturing a hemispherical shell is provided, the hemispherical shell being used for a hemispherical resonant gyroscope, the method comprising: A circular groove is formed on the upper surface of the SOI silicon wafer, and a silicon dioxide protective layer is formed covering the circular groove. A sealing cavity is formed by sealing the annular groove with a glass substrate, and a separation groove is formed by etching a first region of the glass substrate, the first region surrounding the sealing cavity; The glass is heated to form a hemispherical shell.

[0006] In one possible implementation, forming an annular groove on the upper surface of the SOI silicon wafer includes: The upper surface is etched to form a ring, and the ring is deep etched to form an annular groove.

[0007] In one possible implementation, forming the silicon dioxide protective layer covering the annular groove includes: A silicon dioxide protective layer is grown on the upper surface of the SOI silicon wafer; Remove the silicon dioxide protective layer from the area outside the annular groove on the upper surface.

[0008] In one possible implementation, the method of using a glass substrate to seal the annular groove to form a sealed cavity includes: The SOI silicon wafer is bonded to the glass substrate on one side of the annular groove to form a bonding interface, and the glass substrate closes the opening of the annular groove to form the sealed cavity.

[0009] In one possible implementation, etching the first region of the glass substrate to form a separation groove includes: The glass substrate is subjected to photolithography to generate the pattern of the separation groove; The first region of the glass substrate is etched using the pattern to form the separation groove, the bottom of which contacts the SOI silicon wafer.

[0010] In one possible implementation, heating the glass to form a hemispherical shell includes: The glass substrate is heated to a molten state to form a hemispherical shell above the annular groove; The hemispherical shell is separated using the separation groove.

[0011] In one possible implementation, separating the hemispherical shell using the separation groove includes: The area corresponding to the separation groove on the SOI silicon wafer is etched to form a release gap, which surrounds the annular groove and communicates with the sealing cavity.

[0012] In one possible implementation, the area of ​​the hemispherical shell opposite to the annular groove extends away from the annular groove to form an arcuate protrusion, and the middle part of the hemispherical shell contacts the SOI silicon wafer.

[0013] In one possible implementation, the method includes: Metal layers for electrode conductivity and signal extraction are formed on the glass substrates on both sides of the separation groove.

[0014] According to one aspect of the embodiments of this application, a hemispherical resonator gyroscope is provided, the hemispherical resonator gyroscope including a housing and a hemispherical shell as described above, the hemispherical shell being fixed to the housing.

[0015] The beneficial effects of the technical solutions provided in this application are: The method for manufacturing a hemispherical shell provided in this application includes: forming an annular groove on the upper surface of an SOI silicon wafer; forming a silicon dioxide protective layer covering the annular groove; sealing the annular groove with a glass substrate to form a sealed cavity; etching a first region of the glass substrate to form a separation groove, the first region surrounding the sealed cavity; and heating the glass to form a hemispherical shell. The embodiments of this application enable wafer-level manufacturing of the hemispherical shell, shortening processing steps and time, effectively reducing manufacturing costs and improving batch consistency, facilitating large-scale applications. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below.

[0017] Figure 1 A flowchart illustrating a method for manufacturing a hemispherical shell according to an embodiment of this application; Figure 2 This is a cross-sectional schematic diagram of an annular groove formed on an SOI silicon wafer, provided in an embodiment of this application. Figure 3 This is a cross-sectional schematic diagram of a silicon dioxide protective layer formed on an SOI silicon wafer, provided in an embodiment of this application. Figure 4 This is a cross-sectional view of the sealed cavity provided in an embodiment of this application; Figure 5 This is a cross-sectional view of the etching separation groove provided in an embodiment of this application; Figure 6 This is a schematic cross-sectional view of the hemispherical shell after it has been formed, as provided in an embodiment of this application. Figure 7 This is a cross-sectional schematic diagram showing the formation of the release gap as provided in an embodiment of this application; Figure 8 This is a cross-sectional view of the metal layer after its formation, provided in an embodiment of this application. Figure 9 This is a top view of an SOI silicon wafer after an annular groove has been formed, as provided in an embodiment of this application. Figure 10 This is a top view of a glass substrate after a separation groove has been formed, provided as an embodiment of this application. Figure 11 This is a structural diagram of a hemispherical resonant gyroscope provided in an embodiment of this application. Attached image description: 1. SOI silicon wafer; 11. Circular groove; 2. Silica protective layer; 3. Glass substrate; 31. Separation tank; 32. Hemispherical shell; 4. Sealing cavity; 5. Release gap; 6. Metal layer. Detailed Implementation

[0019] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.

[0020] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the terms “comprising” and “including” as used in embodiments of this application mean that the corresponding feature can be implemented as the presented feature, information, data, step, operation, element, and / or component, but do not exclude implementation as other features, information, data, step, operation, element, component, and / or combinations thereof supported by the art. It should be understood that when we say that an element is “connected” or “coupled” to another element, the one element can be directly connected or coupled to the other element, or it can mean that the one element and the other element establish a connection relationship through an intermediate element. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein indicates at least one of the items defined by the term; for example, “A and / or B” indicates implementation as “A,” or implementation as “A,” or implementation as “A and B.”

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0022] The technical solutions of this application and their effects are described below through several exemplary embodiments. It should be noted that the following embodiments can be referenced, borrowed from, or combined with each other. Identical terms, similar features, and similar implementation steps in different embodiments will not be repeated.

[0023] The hemispherical shell manufacturing method and hemispherical resonant gyroscope provided in this application are intended to solve at least one technical problem existing in the prior art.

[0024] Optionally, the hemispherical shell manufacturing method of this application can be used for a hemispherical resonant gyroscope, which can be applied to inertial navigation equipment in many fields such as aviation, aerospace, navigation, and rail transportation.

[0025] Optionally, such as Figures 1-10 (The cross-section in the figure can be a cross-section formed by cutting along a direction perpendicular to the upper surface of SOI silicon wafer 1.) As shown, the hemispherical shell manufacturing method of this application includes: S101: A circular groove 11 is formed on the upper surface of the SOI silicon wafer 1, and a silicon dioxide protective layer 2 is formed covering the circular groove 11.

[0026] Optionally, an annular groove 11 is formed on the upper surface of an SOI (Silicon On Insulator) silicon wafer, including: etching the upper surface to form a ring, and deep silicon etching the ring to form the annular groove 11. The annular groove 11 can be formed by photolithography and etching the upper surface of the SOI silicon wafer 1.

[0027] Optionally, the side (upper surface) of the SOI silicon wafer 1 with the top silicon layer can be etched. During the etching process, a pattern of annular groove 11 is first formed on the photoresist on the upper surface by photolithography. Based on this pattern, the pattern is etched using deep silicon etching (DRIE) technology to form the annular groove 11.

[0028] In one embodiment, the total thickness of the SOI silicon wafer 1 is 500 μm, and the thickness of the top silicon layer is 5 μm. A circular pattern is formed on the SOI silicon wafer 1 using photolithography, and a circular groove 11 is formed using a deep silicon etching (DRIE) process. The bottom of the circular groove 11 extends to the lower silicon layer of the SOI silicon wafer 1. Specifically, the inner diameter of the circular groove 11 can be 2 mm, the outer diameter can be 10 mm, and the depth can be 350 μm.

[0029] Optionally, forming a silicon dioxide protective layer 2 covering the annular groove 11 includes: growing the silicon dioxide protective layer 2 on the upper surface of the SOI silicon wafer 1; and removing the silicon dioxide protective layer 2 from the area outside the annular groove 11 on the upper surface.

[0030] Optionally, the SOI silicon wafer 1 forming the annular groove 11 can be placed in a thermo-oxidative furnace to generate a silicon dioxide protective layer 2 on the surface of the SOI silicon wafer 1 and in the annular groove 11.

[0031] Optionally, when removing the silicon dioxide protective layer 2, CMP (Chemical Mechanical Polishing) can be used to remove the silicon dioxide protective layer 2 in the area outside the annular groove 11 on the upper surface. Alternatively, wet etching or wet etching can be used (but the inner surface of the annular groove 11 needs to be protected to prevent the silicon dioxide protective layer 2 on the inner surface from being removed), thereby exposing a silicon surface suitable for bonding on the upper surface, and using the silicon dioxide protective layer 2 on the surface of the annular groove 11 to protect it from being affected in subsequent production steps.

[0032] S102: The glass substrate 3 is used to close the annular groove 11 to form a sealed cavity 4, and the first area of ​​the glass substrate 3 is etched to form a separation groove 31.

[0033] Optionally, the first region surrounds the sealing cavity 4, and the resulting separation groove 31 can be multiple, with the multiple separation grooves 31 surrounding the annular groove 11.

[0034] Optionally, the glass substrate 3 is used to close the annular groove 11 to form a sealed cavity 4, including: bonding one side of the SOI silicon wafer 1 with the glass substrate 3 to form a bonding interface, and the glass substrate 3 closing the opening of the annular groove 11 to form a sealed cavity 4.

[0035] Optionally, the glass substrate 3 can be the same size as the upper surface of the SOI silicon wafer 1, wherein the glass substrate 3 can be anodicly bonded to the upper surface of the SOI silicon wafer 1 to form a bonding interface. Specifically, the glass substrate 3 can be anodicly bonded to the area outside the annular groove 11 on the upper surface of the SOI silicon wafer 1.

[0036] Alternatively, a glass paste can be used to bond the glass substrate 3 to the SOI silicon wafer 1. A low-melting-point glass paste can be used as an interlayer; the paste is heated and softened before bonding the SOI silicon wafer 1 and the glass substrate 3 to achieve bonding. Alternatively, an ion beam can be used to bombard the area to be bonded on the SOI silicon wafer 1 in an ultra-high vacuum to form a highly active layer, which is then bonded to the glass substrate 3 at room temperature to achieve surface-activated bonding. A metal interlayer (such as gold) can also be introduced between the silicon wafer and the glass substrate 3, heated to its eutectic point (such as gold-silicon 363°C) to fix the glass substrate 3. Other methods that can effectively fix the glass substrate 3 can also be used to form a closed annular groove 11, resulting in a sealed cavity 4.

[0037] Optionally, etching a first region of the glass substrate 3 to form a separation groove 31 includes: performing photolithography on the glass substrate 3 to generate a pattern for the separation groove 31; and using the pattern to etch the first region of the glass substrate 3 to form the separation groove 31, with the bottom of the separation groove 31 contacting the SOI silicon wafer 1.

[0038] Optionally, during photolithography, photoresist can be applied, exposed, and developed (collectively referred to as photolithography) to transfer the mask pattern (i.e., the pattern of the annular groove 11) onto the photoresist on the glass substrate 3. During etching, the area outside the annular groove 11 on the glass substrate 3 is etched based on the pattern on the photoresist to generate the separation groove 31.

[0039] In one embodiment, the separation groove 31 can be located approximately 1 mm outside the edge of the annular groove 11. The position of the separation groove 31 can be determined according to the manufacturing process and the size of the hemispherical resonator gyroscope to be manufactured. The position of the separation groove 31 can be adjusted by the design of the mask plate. Specifically, the outer radius of the annular groove 11 is 5 mm, and the separation groove 31 is etched 1 mm away from the outer side of the annular groove 11. The width of the separation groove 31 can be 0.01 mm, and the separation groove 31 can be located in an annular region with an inner radius of 6 mm and an outer radius of 6.01 mm.

[0040] Optionally, during the etching process of the separation trench 31, the position of the glass substrate 3 corresponding to the separation trench 31 is etched through. Due to the use of selective etching, the etching automatically stops when the lower silicon layer is etched and separates from the subsequent structure.

[0041] Optionally, the separation groove 31 may include an annular groove surrounding the circular groove 11 and a plurality of radial grooves perpendicular to the annular groove, the radial grooves being in communication with the annular groove.

[0042] S103: Heating the glass to form a hemispherical shell 32.

[0043] Optionally, heating the glass to form a hemispherical shell 32 includes: heating the glass substrate 3 to a molten state to form a hemispherical shell 32 above the annular groove 11; and separating the hemispherical shell 32 using a separation groove 31.

[0044] Optionally, the structure formed by bonding the glass substrate 3 and the SOI silicon wafer 1 can be placed in a low-pressure tube furnace and heated to 850°C and held for 5 minutes, so that the glass substrate 3 is in a molten state and undergoes remelting deformation, thereby causing the expansion of the heated gas in the sealed cavity 4 to lift the glass substrate 3 and form a hemispherical shell 32 with a hemispherical cross section above the annular groove 11 (the gas in the annular groove 11 is heated and expanded to form a spherical shell, which is a semi-arched / hemispherical cap-shaped shell structure after forming).

[0045] Alternatively, when heating the glass substrate 3, a hot air circulating furnace, heating tube, heating furnace, or other equipment capable of achieving a stable heating temperature of 850 degrees Celsius can also be used.

[0046] Optionally, the area of ​​the hemispherical shell 32 opposite to the annular groove 11 extends away from the annular groove 11 to form an arc-shaped protrusion, and the middle part of the hemispherical shell 32 contacts the SOI silicon wafer 1.

[0047] In one embodiment, the hemispherical shell 32 formed after heating can be connected end to end along the annular groove 11 to form an annular structure. The glass substrate 3 inside the annular structure can still remain in contact with the SOI silicon wafer 1.

[0048] Optionally, the hemispherical shell 32 is separated using the separation groove 31, including: etching the area of ​​the SOI silicon wafer 1 corresponding to the separation groove 31 to form a release gap 5, the release gap 5 surrounding the annular groove 11 and communicating with the sealing cavity 4.

[0049] In one embodiment, a silicon-silicon dioxide etching process can be used to etch at the corresponding position of the separation groove 31 (the inside of the spherical shell is connected to the outside, and the edge of the hemispherical shell 32 is suspended due to the removal of the silicon below), forming a release gap 5, through which the connection between the hemispherical shell 32 and the outer glass substrate 3 is released.

[0050] Optionally, the method of this application further includes forming a metal layer 6 on the glass substrates 3 on both sides of the separation groove 31 for electrode conduction and signal extraction.

[0051] Optionally, a metal layer 6 can be formed by depositing metal on the upper side of the hemispherical shell 32 and on the glass substrate 3 on the side of the separation groove 31 away from the hemispherical shell 32. The metal layer 6 can be made of gold, silver, copper, or other conductive materials.

[0052] In one embodiment, the metal layer 6 is made of gold. Metals such as Ti / W or Cr can be pre-deposited on the glass substrate 3 as an adhesion layer, and then gold is deposited on the adhesion layer to form the metal layer 6. This metal layer 6 provides conditions for subsequent electrode extraction, excitation, and detection. The metal layers 6 on both sides of the separation groove 31 are not electrically connected; the two metal layers 6 form a capacitor through the separation groove 31.

[0053] Optionally, the radial groove and annular groove in the separation groove 31 can divide the glass substrate 3 outside the annular groove 11 into multiple separate parts, thereby allowing different electrodes to be formed using the metal layer 6.

[0054] Compared with existing technologies, the hemispherical shell manufacturing method of this application forms an annular groove 11 on an SOI silicon wafer 1 through photolithography and deep silicon etching. A silicon dioxide protective layer 2 is generated by thermal oxidation, and the upper surface of the silicon dioxide protective layer 2 is removed by CMP. The layer is then anoly bonded to a glass substrate 3 to form a sealed cavity 4. Subsequently, an etching separation groove 31 is formed on the glass, and the glass is heated in a low-pressure tube furnace to remelt it into a molten state, resulting in a hemispherical shell 32 located above the groove. Then, silicon-silicon dioxide etching is used to release the connection between the middle and outer glass layers. Finally, a metal layer 6 is deposited on the upper and side surfaces of the glass hemispherical shell 32 to achieve conductivity. This method is advantageous for shortening the processing cycle, reducing manufacturing costs, and is suitable for wafer-level fabrication.

[0055] According to one aspect of the embodiments of this application, a hemispherical resonant gyroscope is also provided, such as... Figure 11As shown, the hemispherical resonator gyroscope includes a housing and a hemispherical shell as described in the above embodiment, with the hemispherical shell fixed to the housing. The hemispherical shell may partially or fully enclose the hemispherical shell.

[0056] The terms "first," "second," "third," "fourth," "1," "2," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than that shown in the illustrations or text descriptions.

[0057] It should be understood that although arrows indicate various operation steps in the flowcharts of this application's embodiments, the order in which these steps are implemented is not limited to the order indicated by the arrows. Unless explicitly stated herein, in some implementation scenarios of this application's embodiments, the implementation steps in each flowchart can be executed in other orders as required. Furthermore, some or all steps in each flowchart, based on the actual implementation scenario, may include multiple sub-steps or multiple stages. Some or all of these sub-steps or stages can be executed at the same time, and each sub-step or stage can also be executed at different times. In scenarios where execution times differ, the execution order of these sub-steps or stages can be flexibly configured according to requirements, and this application's embodiments do not limit this.

[0058] The above description is only an optional implementation method for some implementation scenarios of this application. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this application without departing from the technical concept of this application also fall within the protection scope of the embodiments of this application.

Claims

1. A method for manufacturing a hemispherical shell, characterized in that, The hemispherical shell is used for a hemispherical resonant gyroscope, and the method includes: A circular groove is formed on the upper surface of the SOI silicon wafer, and a silicon dioxide protective layer is formed covering the circular groove. A sealing cavity is formed by sealing the annular groove with a glass substrate, and a separation groove is formed by etching a first region of the glass substrate, the first region surrounding the sealing cavity; The glass is heated to form a hemispherical shell.

2. The method for manufacturing a hemispherical shell according to claim 1, characterized in that, The process of forming an annular groove on the upper surface of the SOI silicon wafer includes: The upper surface is etched to form a ring, and the ring is deep etched to form an annular groove.

3. The method for manufacturing a hemispherical shell according to claim 1, characterized in that, The formation of the silica protective layer covering the annular groove includes: A silicon dioxide protective layer is grown on the upper surface of the SOI silicon wafer; Remove the silicon dioxide protective layer from the area outside the annular groove on the upper surface.

4. The method for manufacturing a hemispherical shell according to claim 1, characterized in that, The method of using a glass substrate to seal the annular groove to form a sealed cavity includes: The SOI silicon wafer is bonded to the glass substrate on one side of the annular groove to form a bonding interface, and the glass substrate closes the opening of the annular groove to form the sealed cavity.

5. The method for manufacturing a hemispherical shell according to claim 1, characterized in that, The etching of the first region of the glass substrate forms a separation groove, including: The glass substrate is subjected to photolithography to generate the pattern of the separation groove; The first region of the glass substrate is etched using the pattern to form the separation groove, the bottom of which contacts the SOI silicon wafer.

6. The method for manufacturing a hemispherical shell according to claim 1, characterized in that, The heating of the glass to form a hemispherical shell includes: The glass substrate is heated to a molten state to form a hemispherical shell above the annular groove; The hemispherical shell is separated using the separation groove.

7. The method for manufacturing a hemispherical shell according to claim 6, characterized in that, The process of separating the hemispherical shell using the separation groove includes: The area corresponding to the separation groove on the SOI silicon wafer is etched to form a release gap, which surrounds the annular groove and communicates with the sealing cavity.

8. The method for manufacturing a hemispherical shell according to claim 6, characterized in that, The area of ​​the hemispherical shell opposite to the annular groove extends away from the annular groove to form an arc-shaped protrusion, and the middle part of the hemispherical shell contacts the SOI silicon wafer.

9. The method for manufacturing a hemispherical shell according to claim 6, characterized in that, The method includes: Metal layers for electrode conductivity and signal extraction are formed on the glass substrates on both sides of the separation groove.

10. A hemispherical resonant gyroscope, characterized in that, The hemispherical resonator gyroscope includes a housing and a hemispherical shell as described in any one of claims 1-9, wherein the hemispherical shell is fixed to the housing.

Images