MEMS inertial device manufacturing method
By employing a comb-shaped anchor post bonding method with the device layer wafer in MEMS inertial device manufacturing, the problems of low bonding strength and low process yield have been solved, achieving efficient increase in capacitance and reduction in cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-21
AI Technical Summary
In the current manufacturing of MEMS inertial devices, the bonding strength is not high and the process yield is low, resulting in high production costs.
The method of bonding comb anchors to the device layer wafer involves etching solder joints and comb anchors on the substrate, fabricating conductive holes on the comb anchors after bonding, forming deep holes using TSV process to enhance bonding strength, and forming capacitor combs and capacitor comb anchors on the device layer wafer to improve capacitance.
It improved bonding strength, increased process yield, increased capacitance, reduced device area, and lowered production costs.
Smart Images
Figure CN121894600A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of inertial device technology, specifically to a method for manufacturing MEMS inertial devices. Background Technology
[0002] In the existing technology, inertial devices are usually made using silicon processing technology, which is a technology for processing silicon substrates. It employs techniques such as anisotropic chemical etching, deep silicon etching, self-stopping etching, and wafer bonding to create different micromechanical structures. This technology can be used to manufacture precision microstructures of MEMS and enable high-precision, high-efficiency, and mass production of MEMS devices.
[0003] The existing process involves etching metal traces on a silicon substrate before bonding the device layers. However, the current method suffers from low bonding strength, low process yield, and high production costs. Summary of the Invention
[0004] The purpose of this invention is to provide a method for manufacturing MEMS inertial devices, which can at least solve some of the defects in the prior art.
[0005] To achieve the above objectives, embodiments of the present invention provide the following technical solution: a method for manufacturing MEMS inertial devices, comprising the following steps:
[0006] S1, solder joints and several comb-tooth anchors are etched on the front side of the substrate;
[0007] S2, the device layer wafer is bonded to the substrate through the solder joints and each of the comb-tooth anchor posts;
[0008] S3, after bonding, flip the entire substrate over and grow an isolation layer on the reverse side of the substrate;
[0009] S4, a plurality of conductive holes are made on each of the comb-tooth anchors, the conductive holes extending from the isolation layer into the comb-tooth anchor;
[0010] S5, bonding a cover plate onto the device layer wafer;
[0011] S6, a conductive structure is fabricated on the back side of the substrate, and the device layer wafer is electrically connected to the conductive structure through the conductive via.
[0012] Furthermore, after step S4, the device layer wafer and each of the comb tooth anchors are etched sequentially to form a number of capacitor comb teeth and a number of capacitor comb tooth anchor points, and then the cover plate is bonded on the device layer wafer.
[0013] Furthermore, before sequentially etching the device layer wafer and each of the comb anchors, the entire structure after the conductive holes have been fabricated is flipped over. When the etching point is on the substrate, after etching the comb anchors, etching continues until the substrate is penetrated.
[0014] Furthermore, in step S5, the bonding sites on the cover plate are aligned with the positions of the solder joints on the device layer wafer, and the bonding sites are bonded to the device layer wafer.
[0015] Furthermore, the cover plate, the device layer wafer corresponding to the solder joint, and the substrate enclose a sealed cavity, and each of the capacitor comb teeth and each of the capacitor comb tooth anchor points are located in the sealed cavity.
[0016] Furthermore, in step S4, the fabrication of the conductive hole includes:
[0017] The substrate is etched from the reverse side toward the device layer wafer direction until it penetrates each of the comb anchors to form a plurality of deep holes;
[0018] Metal material is embedded in the deep hole to make the deep hole into the conductive hole.
[0019] Furthermore, the deep hole is formed by etching using the TSV process.
[0020] Furthermore, in step S6, the fabrication of the conductive structure includes: first growing a metal layer, and then fabricating a PAD layer on the metal layer.
[0021] Furthermore, in step S1, the solder joint is a solder ring, which is located at the edge of the substrate.
[0022] Furthermore, the substrate is a silicon substrate, the device layer wafer is a silicon wafer, and the isolation layer is made of silicon dioxide.
[0023] Compared with the prior art, the beneficial effects of the present invention are:
[0024] 1. By using comb-tooth anchors to form several anchor points that bond with the device layer wafer, the bonding strength is improved and the process yield is increased.
[0025] 2. The capacitor comb teeth and capacitor comb tooth anchors formed after etching can increase the capacitance value, improve performance, reduce device area, and reduce cost. Attached Figure Description
[0026] Figure 1 A schematic diagram of etching solder joints and comb-tooth anchors on a substrate in a MEMS inertial device manufacturing method provided in an embodiment of the present invention;
[0027] Figure 2A schematic diagram of a substrate-bonded device layer wafer provided in an embodiment of the present invention for a MEMS inertial device manufacturing method;
[0028] Figure 3 A schematic diagram illustrating the fabrication of conductive holes in a MEMS inertial device manufacturing method according to an embodiment of the present invention;
[0029] Figure 4 This is a schematic diagram illustrating the etching process for forming capacitor comb teeth and capacitor comb tooth anchor points in a MEMS inertial device manufacturing method according to an embodiment of the present invention.
[0030] Figure 5 A schematic diagram of a bonding cover plate for a MEMS inertial device manufacturing method provided in an embodiment of the present invention;
[0031] Figure 6 A schematic diagram illustrating the fabrication of a conductive structure in a MEMS inertial device manufacturing method according to an embodiment of the present invention;
[0032] In the attached figures, the following labels are used: 1-substrate; 10-solder ring; 11-comb anchor post; 12-capacitor comb anchor point; 2-device layer wafer; 20-capacitor comb tooth; 3-conductive via; 4-cover plate; 5-isolation layer; 6-metal layer; 7-PAD layer. Detailed Implementation
[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0034] Please see Figures 1 to 6This invention provides a method for manufacturing a MEMS inertial device, comprising the following steps: S1, etching solder joints and a plurality of comb-tooth anchors 11 on the front side of a substrate 1; S2, bonding a device layer wafer 2 to the substrate 1 via the solder joints and each of the comb-tooth anchors 11; S3, flipping the bonded wafer over and growing an isolation layer 5 on the reverse side of the substrate 1; S4, fabricating a plurality of conductive holes 3 on each of the comb-tooth anchors 11, the conductive holes 3 extending from the isolation layer 5 into the comb-tooth anchors 11; S5, bonding a cover plate 4 to the device layer wafer 2; S6, fabricating a conductive structure on the back side of the substrate 1, the device layer wafer 2 being electrically connected to the conductive structure via the conductive holes 3. Preferably, after step S4, the device layer wafer and each of the comb-tooth anchors are etched sequentially to form a plurality of capacitor comb teeth and a plurality of capacitor comb tooth anchors, and then the cover plate is bonded to the device layer wafer. Before sequentially etching the device layer wafer and each of the comb anchors, the entire wafer after the conductive vias are fabricated is flipped over. When the etching point is on the substrate, after etching the comb anchors, etching continues until the substrate is penetrated. In this embodiment, a large-area substrate comb anchor is first bonded to the device layer. After bonding, the comb anchor electrodes are led out. Then, the device layer is etched to form each capacitor comb tooth 20 and each capacitor anchor. By bonding the large-area substrate anchor to the device layer, the bonding strength is improved, and the process yield is increased. After large-area bonding, small comb teeth and small anchors are etched to increase the capacitance value, improve performance, reduce device area, and reduce cost. Specifically, in existing manufacturing processes, metal traces are first etched on substrate 1 before bonding the device layer wafer 2. However, this bonding strength is not high, leading to a low process yield. Therefore, in this embodiment, comb-tooth anchor posts 11 are etched on the front side of substrate 1. This large-area anchor point bonding can improve the bonding strength. Furthermore, in subsequent processes, after etching the comb-tooth anchor posts 11 into small capacitor comb teeth 20 and small capacitor comb tooth anchor points 12, the capacitance value can be increased. Please refer to... Figure 3 To refine step S2, the entire bonded substrate is first flipped over, and an isolation layer 5 is grown on the reverse side of the substrate 1. Then, the conductive hole 3 in step S3 is fabricated. Growing the isolation layer 5 facilitates the subsequent fabrication of the conductive hole 3. Preferably, the conductive hole 3 extends from the isolation layer 5 into the comb-shaped anchor post 11, i.e., as shown... Figure 3 As shown, the conductive via 3 penetrates the entire substrate 1 and the isolation layer 5 to facilitate the subsequent electrical connection between the conductive structure and the device layer wafer 2 after the conductive structure is grown. Preferably, the isolation layer 5 is made of silicon dioxide. The substrate 1 can be a silicon substrate 1, and the device layer wafer 2 can also be a silicon wafer. Preferably, the solder joint is a solder ring 10, which is located at the edge of the substrate 1.
[0035] Please see Figure 3The fabrication of the conductive via 3 includes: etching the substrate 1 from the reverse side of the substrate 1 toward the device layer wafer 2 until penetrating each of the comb anchor posts 11 to form a plurality of deep holes; and filling the deep holes with metal material to fabricate the deep holes as the conductive via 3. In this embodiment, firstly... Figure 2 The bonded whole is flipped to Figure 3 After thinning the wafer, multiple deep holes are etched on the isolation layer 5 using the TSV process. These deep holes penetrate each comb anchor post 11, and then metal is buried in the deep holes to make them conductive holes 3.
[0036] Please see Figure 4 First, the entire wafer 2 after the conductive hole 3 is fabricated is flipped over. Then, the device layer wafer 2 and each of the comb anchor pillars 11 are etched sequentially. When the etching point is on the substrate 1, after etching the comb anchor pillars 11, etching continues until the substrate 1 is penetrated. In this embodiment, in Figure 3 Based on this, the whole thing is flipped over, and then small capacitor comb anchor points 12 and several capacitor comb teeth 20 can be obtained by etching.
[0037] Please see Figure 5 The bonding sites on the cover plate 4 are aligned with the corresponding solder joints on the device layer wafer 2, and the bonding sites are bonded to the device layer wafer 2. In this embodiment, the cover plate 4 is bonded to the device layer wafer 2, and the solder joint is a solder ring 10. Therefore, the bonding sites on the cover plate 4 can also be annular. The cover plate 4 can be sealed by bonding. Specifically, the cover plate 4, the device layer wafer 2 corresponding to the solder joint, and the substrate 1 enclose a sealed cavity, and each capacitor comb tooth 20 and each capacitor comb tooth anchor point 12 are located in the sealed cavity.
[0038] Please see Figure 5 and Figure 6 The cover plate 4 is bonded onto the device layer wafer 2; a conductive structure is fabricated on the back side of the substrate 1, and the device layer wafer 2 is electrically connected to the conductive structure through the conductive via 3. In this embodiment, after the cover plate 4 is bonded, the entire assembly is flipped over, and a conductive structure is fabricated on the back side of the substrate 1. After the conductive structure is fabricated, a MEMS inertial device can be formed. Preferably, the fabrication of the conductive structure includes: first growing a metal layer 6, and then fabricating a PAD layer 7 on the metal layer 6. Specifically, the metal layer 6 is grown on the isolation layer 5, and then the PAD layer 7 is fabricated on the metal layer 6 at the edge of the substrate 1.
[0039] Thus, the MEMS inertial device fabricated using this method first undergoes large-area comb-tooth anchor bonding with the device layer. After bonding, the comb-tooth anchor electrodes are led out, and then the device layer is etched to form each capacitor comb tooth 20 and each capacitor anchor point. Large-area anchor point bonding improves bonding strength and increases process yield. Etching into smaller comb teeth and smaller anchor points after large-area bonding increases capacitance, improves performance, reduces device area, and lowers cost.
[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for manufacturing a MEMS inertial device, characterized in that, Includes the following steps: S1, solder joints and several comb-tooth anchors are etched on the front side of the substrate; S2, the device layer wafer is bonded to the substrate through the solder joints and each of the comb-tooth anchor posts; S3, after bonding, flip the entire substrate over and grow an isolation layer on the reverse side of the substrate; S4, a plurality of conductive holes are made on each of the comb-tooth anchors, the conductive holes extending from the isolation layer into the comb-tooth anchor; S5, bonding a cover plate onto the device layer wafer; S6, a conductive structure is fabricated on the back side of the substrate, and the device layer wafer is electrically connected to the conductive structure through the conductive via.
2. The MEMS inertial device manufacturing method as described in claim 1, characterized in that: After step S4, the device layer wafer and each of the comb tooth anchors are etched sequentially to form a number of capacitor comb teeth and a number of capacitor comb tooth anchor points, and then the cover plate is bonded on the device layer wafer.
3. The MEMS inertial device manufacturing method as described in claim 2, characterized in that: Before sequentially etching the device layer wafer and each of the comb anchors, the entire structure after the conductive holes have been fabricated is flipped over. When the etching point is on the substrate, after etching the comb anchors, etching continues until the substrate is penetrated.
4. The MEMS inertial device manufacturing method as described in claim 2, characterized in that: In step S5, the bonding sites on the cover plate are aligned with the positions of the solder joints on the device layer wafer, and the bonding sites are bonded to the device layer wafer.
5. The MEMS inertial device manufacturing method as described in claim 4, characterized in that: The cover plate, the device layer wafer corresponding to the solder joint, and the substrate enclose a sealed cavity, and each of the capacitor comb teeth and each of the capacitor comb tooth anchor points are located in the sealed cavity.
6. The MEMS inertial device manufacturing method as described in claim 1, characterized in that, In step S4, the fabrication of the conductive hole includes: The substrate is etched from the reverse side toward the device layer wafer direction until it penetrates each of the comb anchors to form a plurality of deep holes; Metal material is embedded in the deep hole to make the deep hole into the conductive hole.
7. The MEMS inertial device manufacturing method as described in claim 6, characterized in that: The deep hole was formed by etching using the TSV process.
8. The MEMS inertial device manufacturing method as described in claim 1, characterized in that, In step S6, the fabrication of the conductive structure includes: first growing a metal layer, and then fabricating a PAD layer on the metal layer.
9. The MEMS inertial device manufacturing method as described in claim 1, characterized in that: In step S1, the solder joint is a solder ring located at the edge of the substrate.
10. The MEMS inertial device manufacturing method as described in claim 1, characterized in that: The substrate is a silicon substrate, the device layer wafer is a silicon wafer, and the isolation layer is made of silicon dioxide.