# US 2017/0288707 A1 · Lc filter layer stacking by layer transfer to make 3d multiplexer structures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288707 A1 - Document ID: US20170288707A1 - Status: Published application - Kind: A1 - Application number: 15/088,019 - Filed: 2016-03-31 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Changhan Hobie YUN; David Francis BERDY; Chengjie ZUO; Daeik Daniel KIM; Mario Francisco VELEZ; Niranjan Sunil MUDAKATTE; Robert Paul MIKULKA - Web page: https://patentgrep.com/patent/US20170288707A1 ## CPC - H04B 1/0057: {using diplexing or multiplexing filters for selecting the desired band} - H03H 3/00: Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators - H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)} - H03H 7/463: {Duplexers} - H03H 2001/0085: {Multilayer, e.g. LTCC, HTCC, green sheets} - H10W 72/012: {of bump connectors, dummy bumps or thermal bumps} - H04B: TRANSMISSION - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A three dimensional (3D) multiplexer structure may include a first two dimensional (2D) inductor capacitor (LC) filter layer. The first 2D LC filter layer may include a first 2D spiral inductor and a first capacitor(s). The 3D multiplexer structure may also include a second 2D LC filter layer. The second 2D LC filter layer may include a second 2D spiral inductor and a second capacitor(s) stacked directly on and communicably coupled to the first 2D LC filter. ## Claims ### Claim 1 A three dimensional (3D) stacked multiplexer structure, comprising: a first two dimensional (2D) inductor capacitor (LC) filter circuit including a first 2D spiral inductor and at least one first capacitor; and a second 2D LC filter circuit including a second 2D spiral inductor and at least one second capacitor, the second 2D LC filter circuit stacked directly on and communicably coupled to the first 2D LC filter circuit. ### Claim 2 (depends on 1) The 3D stacked multiplexer structure of claim 1, in which the second 2D spiral inductor comprises a copper trace. ### Claim 3 (depends on 1) The 3D stacked multiplexer structure of claim 1, in which the first 2D LC filter circuit comprises a high band filter and the second 2D LC filter circuit comprises a low band filter. ### Claim 4 (depends on 3) The 3D stacked multiplexer structure of claim 3, further comprising a mid-band filter coupled to conductive bumps of the high band filter. ### Claim 5 (depends on 3) The 3D stacked multiplexer structure of claim 3, in which a side of the 3D stacked multiplexer structure, including the low band filter, is a backside of the 3D stacked multiplexer structure, distal from a system board. ### Claim 6 (depends on 1) The 3D stacked multiplexer structure of claim 1, in which the first 2D LC filter layer circuit and the second 2D LC filter circuit are stacked to arrange the first 2D spiral inductor distal from the second 2D spiral inductor. ### Claim 7 (depends on 1) The 3D stacked multiplexer structure of claim 1, in which the first 2D LC filter circuit and the second 2D LC filter circuit are stacked back to back, back to face, face to back, or face to face. ### Claim 8 (depends on 1) The 3D stacked multiplexer structure of claim 1, integrated into a radio frequency (RF) front end module, the RF front end module incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer. ### Claim 9 A method of constructing a three dimensional (3D) stacked multiplexer structure, comprising: fabricating a first two dimensional (2D) inductor capacitor (LC) filter circuit, including a first 2D spiral inductor and at least one first capacitor, on a substrate; fabricating a second LC filter circuit, including a second 2D spiral inductor and at least one second capacitor, on the substrate; removing the substrate from the first 2D LC filter circuit and the second 2D LC filter circuit; and stacking the second 2D LC filter circuit directly on the first 2D LC filter circuit. ### Claim 10 (depends on 9) The method of claim 9, in which the first 2D LC filter circuit is fabricated directly on a first surface of a passive substrate panel and the second 2D LC filter circuit is fabricated directly on a second surface of the passive substrate panel opposite the first surface using a dual-sided printing process. ### Claim 11 (depends on 9) The method of claim 9, in which the first 2D LC filter circuit is fabricated side by side with the second 2D LC filter circuit directly on a surface of a passive substrate panel. ### Claim 12 (depends on 11) The method of claim 11, in which stacking the second 2D LC filter circuit directly on the first 2D LC filter circuit comprises: peeling the passive substrate panel from the first 2D LC filter circuit fabricated side by side with the second 2D LC filter circuit; and folding a backside of the second 2D LC filter circuit onto the backside of the first 2D LC filter circuit according to a back to back integration of the first 2D LC filter circuit and the second 2D LC filter circuit. ### Claim 13 (depends on 9) The method of claim 9, in which removing the substrate comprises using an etching process or a mechanical peeling process to remove the first 2D LC filter circuit and the second 2D LC filter circuit. ### Claim 14 (depends on 9) The method of claim 9, in which the first 2D LC filter circuit is fabricated using a first process and the second 2D LC filter circuit is fabricated using a second process different from the first process. ### Claim 15 (depends on 9) The method of claim 9, further comprising integrating the 3D stacked multiplexer structure into a radio frequency (RF) front end module, the RF front end module incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer. ### Claim 16 A three dimensional (3D) stacked multiplexer structure, comprising: a first two dimensional (2D) inductor capacitor (LC) filter circuit including a 2D spiral inductor and at least one first means for storing charge; and a second 2D LC filter circuit including a second 2D spiral inductor and at least one second means for storing charge, the second 2D LC filter circuit stacked directly on and communicably coupled to the first 2D LC filter circuit. ### Claim 17 (depends on 16) The 3D stacked multiplexer structure of claim 16, in which the first 2D LC filter circuit comprises a high band filter and the second 2D LC filter circuit comprises a low band filter. ### Claim 18 (depends on 17) The 3D stacked multiplexer structure of claim 17, further comprising a mid-band filter coupled to conductive bumps of the high band filter. ### Claim 19 (depends on 17) The 3D stacked multiplexer structure of claim 17, in which a side of the 3D stacked multiplexer structure including the low band filter is a backside of the 3D stacked multiplexer structure that is distal from a system board. ### Claim 20 (depends on 16) The 3D stacked multiplexer structure of claim 16, in which the first 2D LC filter circuit and the second 2D LC filter circuit are stacked to arrange the first 2D spiral inductor distal from the second 2D spiral inductor. ### Claim 21 (depends on 16) The 3D stacked multiplexer structure of claim 16, in which the first 2D LC filter circuit and the second 2D LC filter circuit are stacked back to back, back to face, face to back, or face to face. ### Claim 22 (depends on 16) The 3D stacked multiplexer structure of claim 16, integrated into a radio frequency (RF) front end module, the RF front end module incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer. ### Claim 23 A radio frequency (RF) front end module, comprising: a three dimensional (3D) stacked multiplexer structure, comprising a first two dimensional (2D) inductor capacitor (LC) filter circuit including a first 2D spiral inductor and at least one first capacitor, and a second 2D LC filter circuit including a second 2D spiral inductor and at least one second capacitor, the second 2D LC filter circuit stacked directly on and communicably coupled to the first 2D LC filter circuit; and an antenna coupled to an output of the 3D stacked multiplexer structure. ### Claim 24 (depends on 23) The RF front end module of claim 23, further comprising: a high band antenna switch coupled to the first 2D LC filter circuit through a high band input port of the 3D stacked multiplexer structure; and a low band antenna switch coupled to the second 2D LC filter circuit through a low band input port of the 3D stacked multiplexer structure. ### Claim 25 (depends on 23) The RF front end module of claim 23, in which the first 2D LC filter circuit comprises a high band filter and the second 2D LC filter circuit comprises a low band filter. ### Claim 26 (depends on 25) The RF front end module of claim 25, further comprising a mid-band filter coupled to conductive bumps of the high band filter. ### Claim 27 (depends on 23) The RF front end module of claim 23, incorporated into at least one of a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, a mobile phone, and a portable computer.