# US 2019/0174632 A1 · Flexible printed circuit and electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0174632 A1 - Document ID: US20190174632A1 - Status: Published application - Kind: A1 - Application number: 16/205,864 - Filed: 2018-11-30 - Published: 2019-06-06 - Earliest claimed: 2017-12-05 - Assignees: Canon Components, Inc. - Applicants: Canon Components, Inc. - Inventors: Takaya SHUTO - Web page: https://patentgrep.com/patent/US20190174632A1 ## CPC - H05K 1/115: {Via connections; Lands around holes or via connections (H05K1/112 takes precedence)} - H05K 3/108: {by semi-additive methods; masks therefor (characterised by metallic etch mask H05K3/062; electroplating methods or apparatus H05K3/241)} - H05K 1/112: {directly combined with via connections} - H05K 1/118: {specially for flexible printed circuits, e.g. using folded portions} - H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)} - H05K 3/427: {initial plating of through-holes in metal-clad substrates} - H05K 1/189: characterised by the use of flexible or folded printed circuits - H05K 3/421: {Blind plated via connections (H05K3/422, H05K3/423 and H05K3/425 take precedence)} - H05K 2201/09727: Varying width along a single conductor; Conductors or pads having different widths - H05K 2201/098: Special shape of the cross-section of conductors, e.g. very thick plated conductors - H05K 2201/09827: Tapered, e.g. tapered hole, via or groove - H05K 2203/1383: Temporary protective insulating layer - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract A flexible printed circuit according to the present invention comprises a flexible base, a wiring pattern arranged on the flexible base, and a via that is provided in the flexible base and is electrically connected to the wiring pattern, wherein the wiring pattern is formed to have an aspect ratio of at least 0.7 or more. This feature enables to increase the density of a wiring structure in the flexible printed circuit while improving the reliability thereof. ## Claims ### Claim 1 A flexible printed circuit comprising: a flexible base; a wiring pattern arranged on the flexible base; and a via that is provided in the flexible base and is electrically connected to the wiring pattern, wherein the wiring pattern is formed to have an aspect ratio of at least 0.7 or more. ### Claim 2 (depends on 1) The flexible printed circuit according to claim 1, wherein, in a cross section orthogonal to a direction in which the wiring pattern extends, the width of the wiring pattern in a horizontal direction increases from a lower side toward an upper side, and the wiring pattern includes a portion that satisfies, when the angle of inclination of a side face of the wiring pattern is denoted as θ, 90°<θ<105°. ### Claim 3 (depends on 2) The flexible printed circuit according to claim 2, wherein the portion of the side face of the wiring pattern is curved in a convex shape. ### Claim 4 (depends on 2) The flexible printed circuit according to claim 2, wherein 90°<θ≤100° is further satisfied. ### Claim 5 (depends on 2) The flexible printed circuit according to claim 2, wherein the wiring pattern is formed to have a width in a range from 2 μm to 50 μm and a height in a range from 6 μm to 35 μm. ### Claim 6 (depends on 2) The flexible printed circuit according to claim 2, wherein when, in the cross section, the height from a lower face to an upper face of the wiring pattern is denoted as H, and the distance from an end of the lower face to an end of the upper face of the wiring pattern in a horizontal direction is denoted as D, H/D≥5 is satisfied. ### Claim 7 (depends on 6) The flexible primed circuit according to claim 6, wherein H/D≥10 is further satisfied. ### Claim 8 (depends on 1) The flexible printed circuit according to claim 1, wherein the via includes a metal pillar, and the wiring pattern includes a portion that is connected to the metal pillar from above the metal pillar. ### Claim 9 (depends on 8) The flexible printed circuit according to claim 8, wherein a boundary surface is formed between the metal pillar and the portion of the wiring pattern. ### Claim 10 (depends on 1) The flexible printed circuit according to claim 1, wherein the via includes a metal pillar that is integrally provided so as to extend from below an upper surface of the flexible base to above the upper surface, and the wiring pattern is connected to a pillar upper portion, which is an upper portion of the metal pillar, from a side of the pillar upper portion. ### Claim 11 (depends on 10) The flexible printed circuit according to claim 10, wherein the wiring pattern includes, as its portion, a metal pattern that is integrally connected to the pillar upper portion from a side of the pillar upper portion. ### Claim 12 (depends on 11) The flexible printed circuit according to claim 11, wherein the wiring pattern further includes, the metal pattern being a first metal pattern, a second metal pattern, which is an underlayer of the first metal pattern, and the metal pillar is integrally provided so as to extend from below a boundary surface between the first metal pattern and the second metal pattern to above the boundary surface. ### Claim 13 (depends on 12) The flexible printed circuit according to claim 12, wherein the first metal pattern is made of the same material as the second metal pattern. ### Claim 14 (depends on 12) The flexible printed circuit according to claim 12, wherein the via further includes a metal film that covers a side face of the metal pillar, and the metal film is made of the same material as the second metal pattern. ### Claim 15 (depends on 1) The flexible printed circuit according to claim 1, further comprising, the wiring pattern being a first wiring pattern, a second wiring pattern that is arranged on a lower face of the flexible base, wherein the via electrically connects the first wiring pattern and the second wiring pattern. ### Claim 16 (depends on 1) An electronic device comprising: the flexible printed circuit according to claim 1; and an electronic component to which the flexible printed circuit is connected.