# US 11,305,982 B2 · Eight spring dual substrate MEMS plate switch and method of manufacture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,982 B2 - Document ID: US11305982B2 - Status: Granted - Kind: B2 - Application number: 16/515,943 - Filed: 2019-07-18 - Published: 2021-01-21 - Granted: 2022-04-19 - Earliest claimed: 2019-07-18 - Assignees: Innovative Micro Technology - Applicants: Innovative Micro Technology - Inventors: Christopher S. Gudeman; Paul Rubel - Web page: https://patentgrep.com/patent/US11305982B2 ## CPC - B81B 3/0035: {Constitution or structural means for controlling the movement of the flexible or deformable elements} - H01H 59/0009: {making use of micromechanics} - B81B 3/0027: {Structures for transforming mechanical energy, e.g. potential energy of a spring into translation, sound into translation} - B81B 2203/0163: Spring holders - H01H 2001/0078: {with parallel movement of the movable contact relative to the substrate} - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) ## Abstract Systems and methods for forming an electrostatic MEMS plate switch include forming a deformable plate on a first substrate, forming the electrical contacts on a second substrate, and coupling the two substrates using a hermetic seal. A two-fold symmetric switch may be formed by a primary, secondary, and optionally tertiary set of voids formed in the movable plate. These voids may define the spring beams which provide a stable and reliable restoring force to the switch. ## Claims ### Claim 1 An electrostatic MEMS device, comprising: a first movable plate suspended adjacent to a first substrate and coupled to the first substrate by four pairs of spring beams, wherein the first plate has a square shape with corners and four perpendicular edges, and wherein the each pair has two spring beam members and wherein the two members are substantially collinear and are connected to each corner; at least one electrical contact formed on a second substrate, wherein the first plate is configured to move toward the at least one electrical contact; and a seal which couples the first substrate to the second substrate, and seals the MEMS switch, wherein each pair of spring beams is defined by a primary L-shaped void and a secondary void disposed adjacent and parallel to the primary L-shaped void, at least along a portion of the L-shaped void. ### Claim 2 (depends on 1) The electrostatic MEMS device of claim 1, wherein each of the pairs of spring beams are attached to the substrate by an anchor point at about the midpoint between the two members of the pair of spring beams. ### Claim 3 (depends on 1) The electrostatic MEMS device of claim 1, wherein each spring beam disposed along one side of the first movable plate shares the primary L-shaped void with another spring beam disposed on another side of the first movable plate, wherein the one side and the another side are orthogonal to one another. ### Claim 4 (depends on 1) The electrostatic MEMS device of claim 1, wherein each of the spring beams is configured to flex during electrostatic actuation of the MEMS device, thereby allowing the first movable plate to move towards the at least one electrical contact when the electrostatic MEMS device is actuated, and provide a restoring force when the actuation is ended. ### Claim 5 (depends on 1) The electrostatic MEMS device of claim 1, wherein in addition to the primary L-shaped and secondary voids is a tertiary void, contiguous with the secondary void, and which forms an auxiliary flexion structure, wherein the auxiliary flexion structure contributes more flexibility to the movement of the first movable plate. ### Claim 6 (depends on 5) The electrostatic MEMS device of claim 5, wherein the auxiliary flexion structure is substantially parallel to the pair of spring beams along an edge of the square, along at least a portion of a length of the pair of spring beams. ### Claim 7 (depends on 5) The electrostatic MEMS device of claim 5, wherein the tertiary void is also L-shaped, and includes a 90 degree bend, such that the tertiary void is substantially parallel to the secondary void over a portion of its length, and perpendicular to the secondary void over another portion of its length. ### Claim 8 (depends on 1) The electrostatic MEMS device of claim 1, wherein the first substrate is a silicon-on-insulator substrate including a device layer, a handle layer and a dielectric layer between the device layer and the handle layer, and the second substrate is at least one of a silicon substrate and a silicon-on-insulator substrate. ### Claim 9 (depends on 8) The electrostatic MEMS device of claim 8, further comprising: electrical vias formed through a thickness of the second substrate; and an adjacent electrostatic electrode formed on the second substrate. ### Claim 10 (depends on 8) The electrostatic MEMS device of claim 8, wherein the actuation force arises between the first movable plate and the adjacent electrostatic electrode, when a voltage is applied between the first movable plate and the adjacent electrostatic electrode. ### Claim 11 (depends on 1) The electrostatic MEMS device of claim 1, wherein the seal comprises: a gold/indium alloy which bonds the first substrate to the second substrate with a substantially hermetic seal around the MEMS device. ### Claim 12 A method for manufacturing an electrostatic MEMS device, comprising: forming a first movable plate suspended adjacent to a first substrate and coupled to the first substrate by four pairs of spring beams, wherein the first plate has a square shape with corners and four perpendicular edges, and wherein the each pair of spring beams has two spring beam members which are substantially collinear and are connected to each corner; forming at least one electrical contact on a second substrate, wherein the first plate is configured to move toward the at least one electrical contact; and coupling the first substrate to the second substrate with a seal that seals the MEMS device; wherein each pair of spring beams is defined by a primary L-shaped void and a secondary void disposed adjacent and parallel to the primary L-shaped void, at least along a portion of the L-shaped void. ### Claim 13 (depends on 12) The method of claim 12, wherein each of the pairs of spring beams are attached to the substrate by an anchor point at about the midpoint between the two members of the pair of spring beams. ### Claim 14 (depends on 12) The method of claim 12, wherein each pair of spring beams is formed by a primary L-shaped void and a secondary void disposed adjacent to the L-shaped void, at least along a portion of the L-shaped void. ### Claim 15 (depends on 12) The method of claim 12, wherein each spring beam disposed along one side of the first movable plate shares a primary L-shaped void with another spring beam disposed on another side of the first movable plate, wherein the one side and the another side are orthogonal to one another. ### Claim 16 (depends on 12) The method of claim 12, wherein each of the spring beams is configured to flex during electrostatic actuation of the MEMS device. ### Claim 17 (depends on 12) The method of claim 12, wherein in addition to the primary L-shaped and secondary voids is a tertiary void, contiguous with the secondary void, and which forms an auxiliary flexion structure, wherein the auxiliary flexion structure contributes more flexibility to each of the spring beams. ### Claim 18 (depends on 12) The method of claim 12, wherein the auxiliary flexion structure is defined by an additional L-shaped void formed in the first substrate, adjacent to the first and second voids.