# US 2008/0185518 A1 · High performance micro-fabricated electrostatic quadrupole lens > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0185518 A1 - Document ID: US20080185518A1 - Status: Published application - Kind: A1 - Application number: 12/012,000 - Filed: 2008-01-29 - Published: 2008-08-07 - Earliest claimed: 2007-01-31 - Assignees: Microsaic Systems Limited - Inventors: Richard Syms - Web page: https://patentgrep.com/patent/US20080185518A1 ## CPC - H01J 49/0018: {Microminiaturised spectrometers, e.g. chip-integrated devices, Micro-Electro-Mechanical Systems [MEMS]} - H01J 49/067: {Ion lenses, apertures, skimmers} - H01J 49/4215: {Quadrupole mass filters (H01J49/4225 takes precedence)} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A method of aligning sets of cylindrical electrodes in the geometry of a miniature quadrupole electrostatic lens, which can act as a mass filter in a quadrupole mass spectrometer is provided. The electrodes are mounted in pairs on microfabricated supports, which are formed from conducting parts on an insulating substrate. Complete segmentation of the conducting parts provides low capacitative coupling between co-planar cylindrical electrodes, and allows incorporation of a Brubaker prefilter to improve sensitivity at a given mass resolution. A complete quadrupole is constructed from two such supports, which are spaced apart by further conducting spacers. The spacers are continued around the electrodes to provide a conducting screen. ## Claims ### Claim 1 An electrostatic quadrupole lens comprising first and second microfabricated mounts, each mount having an insulating substrate having formed thereon first and second mounting members configured to receive a first and second electrode respectively, the first and second mounting members being physically distinct from one another. ### Claim 2 (depends on 1) The lens as claimed in claim 1 wherein each mount further includes at least one spacer, the at least one spacer having a height greater than the height of either the first or second mounting members. ### Claim 3 (depends on 2) The lens as claimed in claim 2 wherein each mounting member is formed from two support members, the support members being physically distinct from one another. ### Claim 4 (depends on 2) The lens as claimed in claim 2 wherein each of the support members is formed as an island on the insulating substrate, the individual islands being separated by trenches formed along longitudinal and transverse axes of the mount. ### Claim 5 (depends on 4) The lens as claimed in claim 4 wherein the support members of each mounting member are located at first and second locations on the substrate and separated from one another by the spacer, the spacer forming a shield located between the first and second locations such that a received electrode passes through the shield. ### Claim 6 (depends on 5) The lens as claimed in claim 5 wherein the shield includes a shield trench having a longitudinal axis substantially parallel to the electrode. ### Claim 7 (depends on 6) The mount as claimed in claim 6 wherein the shield trench has a conductive surface, the shield trench having a depth such that when an electrode passes through the shield it is physically separated from the conductive surface of the shield. ### Claim 8 (depends on 6) The lens as claimed in claim 6 wherein each of the first and second mounting members having a conductive surface provided on an upper surface thereof such that when an electrode is received and located on the first and second mounting members electrical contact is effected between the electrode and its respective mounting member. ### Claim 9 (depends on 8) The lens as claimed in claim 8 wherein an inserted electrode is receivable within a locating feature located in an upper surface of either of the first and second mounting members. ### Claim 10 (depends on 9) The lens as claimed in claim 9, wherein the depth of the locating feature is less than the depth of the trench formed in the shield, such that an electrode, when received in the etch feature, is suspended over the trench. ### Claim 11 (depends on 2) The lens as claimed in claim 2 having electrodes received within each of the mounting members. ### Claim 12 (depends on 11) The lens as claimed in claim 11 wherein each of the first and second mounts are arranged in a sandwich structure such that the insulating substrate of each of the first and second mounts are on opposite sides of the structure and provide an outer surface thereof. ### Claim 13 (depends on 12) The lens as claimed in claim 12 wherein on forming the sandwich structure, upper surfaces of the at least one spacer for each of the first and second mounts contact one another, thereby defining the separation distance between the opposing substrates. ### Claim 14 (depends on 13) The lens as claimed in any claim 13 wherein the contact between corresponding spacers provides a continuous conducting shield around the electrodes. ### Claim 15 (depends on 12) The lens as claimed in claim 12 provided in a quadrupole arrangement. ### Claim 16 (depends on 12) The lens as claimed in claim 12 including at least two sets of electrodes, each set being arranged in a quadrupole arrangement. ### Claim 17 (depends on 16) The lens as claimed in claim 16 wherein at least two of the at least two sets of electrodes are arranged in parallel relative to one another. ### Claim 18 (depends on 16) The lens as claimed in claim 16 wherein at least two of the at least two sets of electrodes are arranged serially relative to one another. ### Claim 19 (depends on 18) The lens as claimed in claim 18 wherein a first set of electrodes provides a pre-filter to a second set of electrodes. ### Claim 20 (depends on 19) The lens as claimed in claim 19 wherein the first set of electrodes are mountable on individual mounting members. ### Claim 21 (depends on 19) The lens as claimed in claim 19 wherein the first set of electrodes are mechanically contiguous with but electrically isolated from the second set of electrodes. ### Claim 22 (depends on 18) The lens as claimed in claim 18 wherein the first set of electrodes are coupled to an RF voltage supply. ### Claim 23 (depends on 22) The lens as claimed in claim 22 wherein the first set of electrodes are coupled to a DC ground supply. ### Claim 24 (depends on 12) The lens as claimed in claim 12 wherein external electrical contact to each of the electrodes are provided through bond connections on one of the mounts. ### Claim 25 (depends on 24) The lens as claimed in claim 24 wherein the footprint of each of the two mounts is different such that external access is provided to the mount providing the external electrical connection. ### Claim 26 (depends on 1) The lens as claimed in claim 1 wherein each of the mounting members is formed from a semiconducting material. ### Claim 27 (depends on 26) The lens as claimed in claim 26 wherein the semiconducting material is silicon. ### Claim 28 (depends on 26) The lens as claimed in claim 26 wherein features within the mounting member are defined using photolithographic or etching techniques. ### Claim 29 (depends on 1) The lens as claimed in claim 1 wherein the substrate is formed from a glass. ### Claim 30 (depends on 1) The lens as claimed in claim 1 wherein the substrate is formed from a plastics or ceramic material. ### Claim 31 A quadrupole mass spectrometer comprising a lens formed from first and second microfabricated mounts, each mount having an insulating substrate having formed thereon first and second mounting members configured to receive a first and second electrode respectively, the first and second mounting members being physically distinct from one another. ### Claim 32 A microfabricated quadrupole lens comprising a first set of electrodes provided in a quadrupole configuration and a second set of electrodes provided in a quadrupole configuration the first and second set of electrodes being arranged serially such that the first set provides a pre-filter to the second set, each of the electrodes being coupled to a mounting member that is provided on an insulating substrate and is physically isolated from the mounting member of others of the electrodes.