A MEMS inertial device and its manufacturing process
By adopting a structural design of bonding device layers and top cover plates on a silicon substrate in MEMS inertial devices, the manufacturing process of MEMS inertial devices is simplified, costs are reduced, and miniaturization is achieved, solving the problem of complex metal wiring in existing technologies.
Patent Information
- Application Number
- CN202511196622.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2045-08-26
AI Technical Summary
Existing MEMS inertial devices have complex metal wiring processes, which increase the difficulty of manufacturing, increase costs, and result in large device areas, which is not conducive to miniaturization.
The structure design adopts a bonding device layer and a top cover plate on a silicon substrate. By setting pads and vias on the top cover plate and filling the vias with metal to achieve electrical connection, the trace metal layer covers the vias, avoiding traces on the silicon substrate, simplifying the process and reducing costs.
This reduces the manufacturing difficulty and cost of MEMS inertial devices, while also reducing the device size and achieving miniaturization.
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Figure CN120721071B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of inertial device technology, and in particular to a MEMS inertial device and its manufacturing process. Background Technology
[0002] MEMS inertial devices can be widely used in inertial navigation, drones, autonomous driving, intelligent manufacturing, and high-end industrial fields. In existing technologies, the metal traces of MEMS inertial devices are all completed on a silicon substrate. A metal trace layer is grown on the silicon substrate to allow electrical signals from the inertial device layer to be transmitted to the ASIC circuit through this metal trace layer, ultimately enabling MEMS inertial device detection. The current inertial device structure, where metal traces are all completed on a silicon substrate, has a complex manufacturing process, increasing manufacturing difficulty and reducing yield; it also results in high cost, large device area, and significant space requirements, hindering miniaturization. Summary of the Invention
[0003] The purpose of this invention is to provide a MEMS inertial device and its manufacturing process, aiming to reduce the manufacturing difficulty and cost of MEMS inertial devices. The specific technical solution is as follows:
[0004] A MEMS inertial device includes a silicon substrate, a device layer, a wiring metal layer, and a top cover plate bonded sequentially from bottom to top. The top cover plate has multiple pads on its upper side and multiple through holes corresponding to the multiple pads. The wiring metal layer is electrically connected to the multiple pads through the multiple through holes.
[0005] Furthermore, the silicon substrate is bonded to the device layer via a solder ring.
[0006] Furthermore, the device layer includes a mass block, a moving comb tooth anchor post, a moving comb tooth, a fixed comb tooth, and a beam structure, with the moving comb tooth anchor post bonded to the solder ring; the fixed comb tooth anchor post is also etched on the silicon substrate, and the mass block is supported on the middle of the silicon substrate through the fixed comb tooth anchor post; the trace metal layer is bonded to the moving comb tooth anchor post.
[0007] Furthermore, the fixed comb teeth are distributed around the mass block, the movable comb teeth are distributed around the beam structure, and the movable comb tooth anchor is connected to the movable comb tooth through the beam structure, so that the movable comb tooth is suspended above the silicon substrate, the beam structure is suspended between the movable comb tooth anchor and the movable comb tooth, and the mass block is surrounded within the movable comb tooth anchor.
[0008] Furthermore, the frame edge of the moving comb anchor is 10µm to 50µm wider than the frame edge of the solder ring.
[0009] Furthermore, the wiring metal layer is disposed on the lower side of the upper cover plate, and the lower side of the upper cover plate is also provided with an upper cover plate fixed comb tooth anchor post. The wiring metal layer surrounds the upper cover plate fixed comb tooth anchor post, the wiring metal layer covers the multiple through holes on the outer side, the upper cover plate fixed comb tooth anchor post covers the through hole in the center, and the mass block is bonded to the upper cover plate fixed comb tooth anchor post.
[0010] Furthermore, the wiring metal layer is the same shape and size as the solder ring and the moving comb tooth anchor, forming a square frame, and the upper cover plate fixed comb tooth anchor is the same shape and size as the fixed comb tooth anchor.
[0011] Furthermore, the beam structure includes a square frame and four straight beams that connect the square frame to the corresponding sides of the moving comb tooth anchor.
[0012] Furthermore, three pads are provided, arranged in a straight line on the upper cover plate, two located at the edge of the upper cover plate and one located at the center of the upper cover plate.
[0013] The present invention also provides a manufacturing process for a MEMS inertial device, for manufacturing the MEMS inertial device as described above, comprising the following steps:
[0014] S100: Etch the solder ring and the fixed comb tooth anchor on the silicon substrate; bond the device layer and etch the mass block, the moving comb tooth anchor, the moving comb tooth, the fixed comb tooth, and the beam structure.
[0015] S200: The pads are grown on the upper side of the upper cover plate wafer; a layer of SiO2 is grown on the lower side of the upper cover plate wafer, the vias are etched, and metal is filled to connect with the pads; trace metal is grown on the lower side of the SiO2 layer, and the trace metal is etched to form the trace metal layer and the upper cover plate fixed comb tooth anchor.
[0016] S300: Bond the upper cover plate to the device layer and the silicon substrate to form a MEMS inertial device.
[0017] The present invention provides a MEMS inertial device and its manufacturing process, which have the following beneficial effects:
[0018] This invention involves setting a device layer bonded on a silicon substrate; a top cover plate has multiple pads on its upper side and multiple through holes corresponding to the pads, with metal filled in the through holes for electrical connection with the pads; a trace metal layer is set on the lower side of the top cover plate, covering at least a portion of the through holes; the top cover plate is bonded to the device layer through the trace metal layer; this allows the metal trace layer to run on the device layer instead of the substrate, extracting signals from the cover plate, avoiding the complex process flow caused by running on the substrate, and reducing the manufacturing difficulty of MEMS inertial devices; furthermore, the trace metal layer between the cover plate and the device layer can serve as a solder ring to connect the cover plate and the device layer, and can also be used for signal connection, which can reduce the size and cost of MEMS inertial devices. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the MEMS inertial device provided by the present invention;
[0020] Figure 2 This is a schematic diagram of the silicon substrate structure of the present invention;
[0021] Figure 3 This is a schematic diagram of the silicon substrate bonding device layer of the present invention;
[0022] Figure 4 This is a schematic diagram of the upper side of the cover plate of the present invention;
[0023] Figure 5 This is a partial structural diagram of the lower side of the upper cover plate of the present invention;
[0024] Figure 6 This is a schematic diagram of the structure of the lower side of the upper cover plate of the present invention;
[0025] Figure 7 This is a schematic diagram of the first step of the TSV process for the MEMS inertial device of the present invention.
[0026] Figure 8 This is a schematic diagram of the second step of the TSV process for the MEMS inertial device of the present invention.
[0027] Figure 9 This is a schematic diagram of the third step of the TSV process for the MEMS inertial device of this invention. Detailed Implementation
[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.
[0029] Example 1: This example provides a MEMS inertial device 10, see reference. Figure 1 As shown, it includes a silicon substrate 100, a device layer 200, a wiring metal layer 330, and a cover plate 300 bonded sequentially from bottom to top.
[0030] See Figure 2 As shown, a solder ring 110 and a fixed comb anchor 120 are etched on the silicon substrate 100. In a preferred embodiment, the silicon substrate 100 is square, and the solder ring 110 is a square frame aligned with the edge of the silicon substrate 100. The fixed comb anchor 120 is cylindrical.
[0031] See Figure 3 As shown, a device layer 200 is bonded on a silicon substrate 100. The device layer 200 includes a mass block 210, a moving comb anchor post 220, a moving comb tooth 230, a fixed comb tooth 240, and a beam structure 250.
[0032] The movable comb-tooth anchor 220 is bonded to the solder ring 110. In a preferred embodiment, the movable comb-tooth anchor is square-shaped, and the frame edge of the movable comb-tooth anchor is 10µm to 50µm wider than the frame edge of the solder ring to prevent metal overflow after bonding.
[0033] The mass block 210 is supported on the center of the silicon substrate 100 by the fixed comb-tooth anchor post 120. In a preferred embodiment, the mass block 210 is square.
[0034] Fixed comb teeth 240 are distributed around the mass block 210, and movable comb teeth 230 are distributed around the beam structure 250. In one embodiment, the movable comb teeth 230 correspond one-to-one with the fixed comb teeth 240.
[0035] The movable comb tooth anchor post 220 is connected to the movable comb tooth 230 via a beam structure 250, allowing the movable comb tooth 230 to be suspended above the silicon substrate 100. The beam structure 250 is suspended between the movable comb tooth anchor post 220 and the movable comb tooth 230, and surrounds the mass block 210 within the movable comb tooth anchor post 220. In this embodiment, the device layer is connected to the device structure in a suspended state by a beam using a solder ring as an anchor point, effectively reducing device stress and improving performance indicators.
[0036] In a preferred embodiment, the beam structure 250 includes a square frame and four straight beams connecting the square frame to the corresponding sides of the movable comb tooth anchor 220. Optionally, the beam structure 250 can be a straight beam structure as shown in the figure, or it can be a U-shaped beam or an L-shaped beam.
[0037] See Figure 4-6 As shown, a plurality of pads 310 are provided on the upper side of the upper cover plate 300. In a preferred embodiment, three square pads 310 are provided, arranged in a straight line on the upper cover plate 300, two of which are located at the edge of the upper cover plate 300 and one is located at the center of the upper cover plate 300.
[0038] The upper cover plate 300 is also provided with a plurality of through holes 320 corresponding to a plurality of solder pads 310, and the plurality of through holes 320 are filled with metal to conduct electricity to the plurality of solder pads 310. In a preferred embodiment, the through holes 320 are square.
[0039] A wiring metal layer 330 and a fixed comb tooth anchor 340 are provided on the lower side of the upper cover plate 300. The wiring metal layer surrounds the fixed comb tooth anchor, and the wiring metal layer 330 covers multiple through holes 320 on the outer side. The fixed comb tooth anchor 340 covers the central through hole 320. In a preferred embodiment, the wiring metal layer 330 is the same shape and size as the solder ring 110 and the moving comb tooth anchor 220, forming a square frame. The fixed comb tooth anchor 340 is the same shape and size as the fixed comb tooth anchor 120.
[0040] See Figure 1 As shown, the upper cover plate 300 is bonded to the device layer 200 and the silicon substrate 100 to form a MEMS inertial device. The upper cover plate 300 and the device layer 200 are bonded to the moving comb tooth anchor post 220 through the wiring metal layer 330, which serves as the bonding ring of the upper cover plate 300. The mass block 210 is bonded to the fixed comb tooth anchor post 340 of the upper cover plate.
[0041] Example 2: This example provides a manufacturing process for a MEMS inertial device, used to manufacture the MEMS inertial device 10 as described above, including the following steps:
[0042] S100, see reference Figure 7 As shown, a solder ring 110 and a fixed comb tooth anchor post 120 are etched on a silicon substrate 100; a bonding device layer 200 is bonded and etched to form a mass block 210, a moving comb tooth anchor post 220, a moving comb tooth 230, a fixed comb tooth 240, and a beam structure 250.
[0043] S200, see reference Figure 8 As shown, pads 310 are grown on the upper side of the cover plate (CAP) 300 wafer; a layer of SiO2 is grown on the lower side of the cover plate 300 wafer, through-hole vias (TSVs) 320 are etched, and metal is filled to connect them to the pads 310; trace metal is grown on the lower side of the SiO2 layer, and the trace metal is etched to form a trace metal layer 330 and a CAP fixed comb anchor post 340. In this embodiment, the TSV process is used to directly introduce electrical signals into the top layer of the device, simplifying the process steps.
[0044] S300, see reference Figure 9 As shown, the upper cover plate 300 is bonded to the device layer 200 and the silicon substrate 100 to form a MEMS inertial device 10.
[0045] It should be noted that steps S100 and S200 are not in any particular order.
[0046] Those skilled in the art should understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the invention. Any changes or modifications made by those skilled in the art based on the embodiments of the present invention and the above disclosure shall fall within the protection scope of the claims.
Claims
1. A MEMS inertial device, characterized by, The MEMS inertial device comprises, from bottom to top, a silicon substrate, a device layer, a metal layer for wiring, and an upper cover plate. The upper side of the upper cover plate is provided with a plurality of pads. A plurality of through holes corresponding to the pads are formed in the upper cover plate. The metal layer for wiring is electrically connected to the pads through the through holes. The metal layer for wiring is arranged on the lower side of the upper cover plate. The lower side of the upper cover plate is further provided with an upper cover plate fixed comb anchor column. The metal layer for wiring surrounds the upper cover plate fixed comb anchor column. The metal layer for wiring covers a plurality of through holes on the outer side. The upper cover plate fixed comb anchor column covers the through hole in the center. The device layer comprises a mass block. The mass block is bonded to the upper cover plate fixed comb anchor column.
2. The MEMS inertial device of claim 1, wherein, The silicon substrate and the device layer are bonded by a solder ring.
3. The MEMS inertial device of claim 2, wherein, The device layer further comprises a moving comb anchor column, a moving comb, a fixed comb, and a beam structure. The moving comb anchor column is bonded to the solder ring. The silicon substrate is further etched with a fixed comb anchor column. The mass block is carried on the middle part of the silicon substrate through the fixed comb anchor column. The metal layer for wiring is bonded to the moving comb anchor column.
4. The MEMS inertial device of claim 3, wherein, The fixed comb is distributed around the mass block. The moving comb is distributed around the beam structure. The moving comb anchor column is connected to the moving comb through the beam structure. The moving comb is suspended on the silicon substrate. The beam structure is suspended between the moving comb anchor column and the moving comb. The mass block is surrounded by the moving comb anchor column.
5. The MEMS inertial device of claim 3, wherein, The frame of the moving comb anchor column is 10-50 um wider than the frame of the solder ring.
6. The MEMS inertial device of claim 3, wherein, The metal layer for wiring is consistent in shape and size with the solder ring and the moving comb anchor column, and is in the shape of a square frame. The upper cover plate fixed comb anchor column is consistent in shape and size with the fixed comb anchor column.
7. The MEMS inertial device of claim 6, wherein, The beam structure comprises a square frame and four straight beams connecting the square frame to the corresponding sides of the moving comb anchor column.
8. The MEMS inertial device of claim 5, wherein, Three pads are arranged in a straight line on the upper cover plate, two of which are located at the edges of the upper cover plate, and one of which is located at the center of the upper cover plate.
9. A manufacturing process of a MEMS inertial device, for manufacturing the MEMS inertial device according to any one of claims 1-8, comprising the following steps: S100, etching the solder ring and the fixed comb anchor column on the silicon substrate; bonding the device layer, and etching the mass block, the moving comb anchor column, the moving comb, the fixed comb, and the beam structure; S200, growing the pads on the upper side of the upper cover plate wafer; growing a layer of SiO2 on the lower side of the upper cover plate wafer, etching the through holes, and filling metal to connect the pads; growing the metal layer for wiring on the lower side of the SiO2 layer, and etching the metal layer for wiring to form the upper cover plate fixed comb anchor column; S300, bonding the upper cover plate to the device layer and the silicon substrate to form the MEMS inertial device.
Citation Information
Patent Citations
Two-axis MEMS (Micro Electro Mechanical System) circular ring gyroscope and preparation and packaging method thereof
CN113607153A