MEMS switch with planar through-glass via
By designing a plane through-glass through-glass (TGV) in the MEMS element, the problem that MEMS element is difficult to maintain airtightness when transmitting electrical signals is solved, and efficient and stable signal transmission is achieved.
Patent Information
- Application Number
- CN202411516448.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-10-31
- Filing Date
- 2024-10-29
- Publication Date
- 2025-05-02
AI Technical Summary
Existing MEMS components are difficult to maintain airtightness when transmitting electrical signals, resulting in low signal transmission efficiency.
A flat through-glass through glass (TGV) is designed, which passes through the glass cap or substrate, ensuring that electrical signals can be transmitted without destroying airtightness. The construction of the TGV involves applying a metal conformal coating to the inner wall of the void of the glass cap or substrate and filling the void with flexible composite material to achieve the dual requirements of conductivity and airtightness.
Through the design of TGV, the efficiency and airtightness of MEMS components when transmitting electrical signals are achieved, ensuring the stability of signal transmission and low leakage rate.
Smart Images
Figure CN119920655A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a MEMS switch having a planar through-glass via. Background Art
[0002] A microelectromechanical system (MEMS) element may include: a MEMS device on a glass substrate; and a glass cap (or cover) arranged to encapsulate the MEMS device within an airtight cavity. Electrical signals originating from outside the MEMS element may need to be transmitted to / from the MEMS device without affecting the airtightness of the airtight cavity. Summary of the invention
[0003] The described embodiments of the present invention relate to a microelectromechanical system (MEMS) element, which includes a MEMS device on a glass substrate and a glass cap (or lid or cover) bonded to the substrate to form an airtight cavity that accommodates the MEMS device. The MEMS element also includes at least one planar through-glass via (TGV) that facilitates the transmission of electrical signals from the MEMS device within the cavity to a device or system outside the cavity (or vice versa). The TGV is constructed and arranged to prevent gas from flowing into or out of the cavity through the TGV. In the exemplary embodiments described herein, the TGV is implemented in the glass cap, although in other embodiments, the TGV can be implemented in the device substrate. As described in more detail herein, a "planar" TGV means that the ends of the TGV are planar, so that, for example, the ends of the TGV can be coplanar with the outer surface of the cap.
[0004] In one aspect, the present invention may be a microelectromechanical system (MEMS) component comprising: a glass substrate; a MEMS device disposed on the glass substrate; and a glass cap, the glass cap: (i) having at least one conductive via extending through the glass cap; and (ii) attached to the glass substrate, thereby encapsulating and hermetically sealing the MEMS device within a cavity. The at least one conductive via may have a top planar end cap coupled to a top end of the conductive via and a bottom planar end cap coupled to a bottom end of the conductive via.
[0005] In one embodiment, the at least one conductive via may be cylindrical. The at least one conductive via may include a metal conformal coating on the inner wall of the void extending through the glass cap, such that the conformal coating surrounds the remaining void. The remaining void may be filled with a flexible composite material from the top end to the bottom end. The flexible composite material may be conductive or substantially non-conductive.
[0006] The flexible composite material may include a mixture of materials that form an airtight seal from the top end to the bottom end. The top surface of the top planar end cap may be substantially coplanar with the top surface of the glass cap, and the bottom surface of the bottom planar end cap may be substantially coplanar with the bottom surface of the glass cap. The bottom planar end cap may be electrically coupled to the MEMS device. The glass cap may be bonded to the glass substrate such that the MEMS device is hermetically sealed within a cavity formed between the glass substrate and the glass cap.
[0007] On the other hand, the present invention may be a microelectromechanical system (MEMS) element, which includes a glass substrate, a MEMS device disposed on the glass substrate, and a glass cap disposed on the glass substrate. The glass cap may have at least one conductive via that passes through the glass cap. The conductive via may include a cylindrical void that passes through the glass cap from the top surface of the glass cap to the bottom surface of the glass cap and a metal conformal coating disposed on the inner side wall of the cylindrical void. The metal conformal coating may have a top end at the top surface of the glass cap and a bottom end at the bottom surface of the glass cap. The conductive via may further include a flexible composite material disposed in the cylindrical void from the top surface of the glass cap to the bottom surface of the glass cap, a top planar end cap coupled to the top end of the metal conformal coating, and a bottom planar end cap coupled to the bottom end of the metal conformal coating.
[0008] The glass cap may be bonded to the glass substrate such that the MEMS device is hermetically sealed within a cavity formed between the glass substrate and the glass cap. The flexible composite material may be conductive or non-conductive. The flexible composite material may include a mixture of materials that form a hermetic seal from the top end to the bottom end. The top surface of the top planar end cap may be substantially coplanar with the top surface of the glass cap, and the bottom surface of the bottom planar end cap may be substantially coplanar with the bottom surface of the glass cap.
[0009] In another aspect, the present invention may be a method of transmitting an electrical signal to a packaged microelectromechanical (MEMS) device, the method comprising: providing a MEMS device disposed on a glass substrate; and forming at least one conductive via extending through a glass cap. The at least one conductive via may have a top planar end cap coupled to a top end of the conductive via and a bottom planar end cap coupled to a bottom end of the conductive via. The method may also include: attaching the glass cap to the glass substrate, thereby encapsulating and hermetically sealing the MEMS device within a cavity.
[0010] The method may also include: bonding the glass cap to the glass substrate so that the MEMS device is hermetically sealed in a cavity formed between the glass substrate and the glass cap. The method may also include: electrically coupling the bottom planar end cap to the MEMS device. The method may also include: manufacturing the top surface of the top planar end cap to be substantially coplanar with the top surface of the glass cap; and manufacturing the bottom surface of the bottom planar end cap to be substantially coplanar with the bottom surface of the glass cap. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The foregoing will be apparent from the following more particular description of exemplary embodiments, as illustrated in the accompanying drawings, in which like reference numerals refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the embodiments.
[0012] Figure 1A and Figure 1B An exemplary MEMS element structure is shown.
[0013] Figure 2 A cross-sectional view of a shrunk via is shown.
[0014] Figure 3A An exemplary embodiment of a hybrid via according to the present invention is shown.
[0015] Figure 3B It shows that according to the present invention Figure 3A A more detailed view of the hybrid via is shown.
[0016] Figure 4 Reference to an exemplary MEMS element architecture is shown. Figure 3A and Figure 3B Describes the mixed vias.
[0017] Figure 5 A hybrid via is shown through the glass substrate. DETAILED DESCRIPTION
[0018] A description of exemplary embodiments follows.
[0019] Micro-electromechanical systems (MEMS) components can consist of two-piece structures, such as Figure 1A The first part includes a MEMS device structure 10 built on a glass substrate 12, and the second part includes a glass cap 14, as shown in FIG. Figure 1B As shown, a glass cap 14 surrounds and covers the MEMS device structure 10 to form an airtight cavity 16 in which the MEMS device structure 10 is located.
[0020] The glass cap 14 and the glass substrate 12 may be made of any of a variety of glass materials, such as silicon dioxide (SiO 2), fused silica, quartz glass, crystal, sodium-doped glass, and borosilicate glass. In other embodiments, the substrate and cap can be composed of non-glass materials, such as silicon (Si), silicon carbide (SiC), and gallium nitride (GaN), although other non-glass materials can also be used.
[0021] One or more electrical conductors 18 may pass through the glass cap 14 to the MEMS device structure 10 to provide an electrical path from outside the airtight cavity 16 to the MEMS device structure 10. These electrical conductors 18 may be in the form of through-glass vias (TGVs) 18 that facilitate the transmission of electrical signals through the glass cap 14 while maintaining the airtightness of the airtight cavity 16. The embodiments described herein may be configured to provide an airtight seal between the device environment within the airtight cavity 16 and the external environment 22, which can provide an airtight seal of less than 1.0×10 -6 (atm-cm) 3 / s measured helium leak rate.
[0022] The conductive material within the TGV 18 may be copper, a gold layer 20a is coupled to the bottom (i.e., substrate-facing) end of the TGV 18, and a gold layer 20b (external pad) is coupled to the top of the TGV 18. A gold layer 20c is disposed on the substrate 12 and electrically coupled to the MEMS device structure 10. The gold layer 20a at the bottom of the TGV 18 is coupled to the gold layer 20c on the substrate 12 by thermocompression bonding, thereby forming an airtight cavity 16, as shown in FIG. Figure 1B shown.
[0023] Figure 1A and Figure 1B Certain aspects of the MEMS elements shown may complicate the implementation of the TGV 18. For example, these aspects may include: (i) the requirement to hermetically seal the MEMS device cavity; (ii) the need to relieve stress applied to the glass surrounding the TGV when the glass and TGV materials have different coefficients of thermal expansion (CTE); and (iii) the need to prevent contaminants from being introduced into the MEMS device cavity.
[0024] Conformal plating of the void of the TGV opening can provide a conductive path through the glass cap or glass substrate without exerting stress on the surrounding glass because the conformal plating is much less sensitive to the CTE-induced stresses produced by a fully filled metal via. That is, the conformally filled via is constrained only along the outer walls and is therefore free to expand in more directions at elevated temperatures, thus producing lower stresses. However, the conformal plating only lines the inner walls of the TGV void, so it cannot support the TGV in maintaining a hermetic seal.
[0025] A TGV completely filled with metal or other conductive material provides a conductive path, can support the TGV to maintain a hermetic seal, and can support a flat planar end cap. The CTE of the filler metal can be different enough from the CTE of the surrounding glass that the stresses due to the CTE difference can crack or otherwise damage the glass if the temperature is too high.
[0026] like Figure 2 As shown, the constricted TGV 200 provides a conductive path, and the shape of the constricted via 200 is designed to provide relief for CTE-induced stress on the surrounding glass. In addition, the constricted via conductor 202 is completely filled at the constricted area 204, which facilitates hermetic sealing of the MEMS device cavity.
[0027] However, the via cavity 206 can provide a reservoir for collecting contaminants. Even though the via cavity is relatively shallow, it is difficult to completely remove these contaminants. During high temperature processing (e.g., thermal bonding of the glass cap to the glass substrate), the contaminants may be released into the sealed MEMS device cavity and cause performance degradation and / or instability of the MEMS device.
[0028] The described embodiments are directed to a hybrid TGV architecture that combines the advantages of several types of TGV architectures. Figure 3A The hybrid TGV architecture of the illustrated exemplary embodiment implements a TGV in which a conformal plating layer 302 extends through glass 306 (e.g., a glass device substrate or a glass cap / cover), wherein the TGV void is filled with a composite material 308. The composite material 308 can be conductive or non-conductive, since in the case of a non-conductive composite material 308, the conformal plating layer 302 provides conductivity of the TGV through the glass. The composite material 308 can be (i) sufficiently flexible to provide relief of CTE differences between the TGV and the surrounding glass (as with a constricted via); and (ii) facilitate hermetic sealing of the TGV between the outer surface of the glass exterior 310 and the glass interior 312 by preventing contaminants from flowing through the TGV. Figure 3A and Figure 3B Each end of the TGV shown in FIG. 1 is terminated by a top planar end cap 304a and a bottom planar end cap 304b. The end caps 304a, 304b are constructed and arranged so that the outer surface of the top planar end cap 304a is coplanar with the surface of the glass exterior 310 and the bottom planar end cap 304b is coplanar with the surface of the glass interior 312.
[0029] Figure 4 An exemplary embodiment of a MEMS element according to the present invention is shown. Figure 1A and Figure 1B The hybrid vias 402a, 402b are shown in the associated exemplary architecture and are described in detail herein and in Figure 3Aand Figure 3B The cap 14 is attached to the substrate 12 using thermocompression bonding, thereby forming a hermetic cavity 16 encapsulating the MEMS device structure 10 .
[0030] The embodiments herein relate to a hybrid via that passes through a glass cap. The hybrid via described herein can also be used to route signals through a device substrate. Figure 5 An exemplary embodiment is shown that includes a hybrid via 402c extending from a bottom surface 502 of the glass substrate 12 to a top surface 504 of the glass substrate.
[0031] While exemplary embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments as encompassed by the following claims.
Claims
1. A micro-electromechanical system component, comprising: Glass substrate; A micro-electro-mechanical system device, wherein the micro-electro-mechanical system device is arranged on the glass substrate; A glass cap: (i) having at least one conductive via extending through the glass cap; and (ii) attached to the glass substrate to encapsulate and hermetically seal the micro-electromechanical system device within a cavity, the at least one conductive via having a top planar end cap coupled to a top end of the conductive via and a bottom planar end cap coupled to a bottom end of the conductive via.
2. The MEMS component according to claim 1, wherein: The at least one conductive via is cylindrical.
3. The MEMS component according to claim 2, wherein: The at least one conductive via includes a metal conformal coating on inner walls of a void extending through the glass cap such that the conformal coating surrounds a remaining void.
4. The MEMS component according to claim 3, wherein: The remaining space is filled with a flexible composite material from the top end to the bottom end.
5. The MEMS component according to claim 4, wherein: The flexible composite material is electrically conductive.
6. The MEMS component according to claim 4, wherein: The flexible composite material is substantially electrically non-conductive.
7. The MEMS component according to claim 4, wherein: The flexible composite material includes a mixture of materials that forms an airtight seal from the top end to the bottom end.
8. The MEMS component according to claim 4, wherein: The top surface of the top planar end cap is substantially coplanar with the top surface of the glass cap, and the bottom surface of the bottom planar end cap is substantially coplanar with the bottom surface of the glass cap.
9. The MEMS component according to claim 1, wherein: The bottom planar end cap is electrically coupled to the MEMS device.
10. The MEMS component according to claim 1, wherein: The glass end cap is bonded to the glass substrate such that the MEMS device is hermetically sealed within a cavity formed between the glass substrate and the glass cap.
11. A micro-electromechanical system component, comprising: Glass substrate; A micro-electro-mechanical system device, wherein the micro-electro-mechanical system device is arranged on the glass substrate; A glass cap, the glass cap is disposed on the glass substrate, the glass cap has at least one conductive via penetrating the glass cap, and the conductive via comprises: (i) a cylindrical void extending through the glass cap from a top surface of the glass cap to a bottom surface of the glass cap; (ii) a metal conformal coating disposed on an inner sidewall of the cylindrical void, The metal conformal coating has a top end at the top surface of the glass cap and a bottom end at the bottom surface of the glass cap; (iii) a flexible composite material disposed in the cylindrical gap from the top surface of the glass cap to the bottom surface of the glass cap; (iv) a top planar end cap coupled to a top end of the metal conformal coating; and (v) a bottom planar end cap coupled to the bottom end of the metallic conformal coating.
12. The MEMS component according to claim 11, wherein: The glass cap is bonded to the glass substrate such that the MEMS device is hermetically sealed within a cavity formed between the glass substrate and the glass cap.
13. The MEMS component according to claim 11, wherein: The flexible composite material is electrically conductive.
14. The MEMS component according to claim 11, wherein: The flexible composite material is substantially electrically non-conductive.
15. The MEMS component according to claim 11, wherein: The flexible composite material includes a mixture of materials that forms an airtight seal from the top end to the bottom end.
16. The MEMS component according to claim 11, wherein: The top surface of the top planar end cap is substantially coplanar with the top surface of the glass cap, and the bottom surface of the bottom planar end cap is substantially coplanar with the bottom surface of the glass cap.
17. A method for transmitting an electrical signal to a packaged micro-electromechanical system device, the method comprising: Providing a micro-electromechanical system device disposed on a glass substrate; forming at least one conductive via through the glass cap, the at least one conductive via having a top planar end cap coupled to a top end of the conductive via and a bottom planar end cap coupled to a bottom end of the conductive via; and The glass cap is attached to the glass substrate, thereby encapsulating and hermetically sealing the MEMS device within the cavity.
18. The method according to claim 17, further comprising: The glass cap is bonded to the glass substrate such that the MEMS device is hermetically sealed within a cavity formed between the glass substrate and the glass cap.
19. The method according to claim 17, further comprising: The bottom planar end cap is electrically coupled to the micro-electromechanical systems device.
20. The method according to claim 17, further comprising: manufacturing a top surface of the top planar end cap to be substantially coplanar with a top surface of the glass cap; And the bottom surface of the bottom planar end cap is manufactured to be substantially coplanar with the bottom surface of the glass cap.