EP0526243A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Via hole structure and process
Assignee: Fujitsu Ltd
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Filing: 1992-07-31
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Granted: —
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Expires: 2012-07-31
Abstract
Abstract When an insulating film of a multilayer interconnected board or the like is made of two or more coatings so as to build up the required thickness, it can be difficult to provide a via hole with a suitably tapered shape such that when a metallic film for wiring is formed on the composite insulating film, the metal film can completely fill up the via holes. The via holes 7 of the invention are given a gradually increasing diameter from the bottom toward the top of the insulating layer 8 comprising a plurality of preferably photosensitive insulating resin films 2,5, by forming an aperture in each film 2,5 as it is applied, these apertures having successively smaller diameters.
Inventors
- 👤 Motoaki Fujitsu Ltd. 1015 Kamikodanaka Tani
- 👤 Shoichi Fujitsu Ltd. 1015 Kamikodanaka Miyahara
- 👤 Makoto Fujitsu Ltd. 1015 Kamikodanaka Sasaki
- 👤 Eiji Fujitsu Ltd. 1015 Kamikodanaka Horikoshi
- 👤 Isao Fujitsu Ltd. 1015 Kamikodanaka Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 21:21
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0017; H05K3/0023; H10; H10W; H10W70/00; H10W70/01; H10W70/05; H10W70/095; H10W70/60; H10W70/62; H10W70/63; H10W70/635; H05K2201/00; H05K2201/01; H05K2201/0183; H05K2201/0195; H05K2201/09; H05K2201/09209; H05K2201/095; H05K2201/09509; H05K2201/09818; H05K2201/09827; H05K2201/09845; H05K3/46; H05K3/4644
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
70 words
A via hole structure of a multilayer interconnected board including an insulating layer (8), itself comprising a plurality of insulating resin films (2,5), and an electrically conducting wiring layer (13) lying on the insulating layer (8) and filling the via hole (7), characterised in that the aperture of the via hole (7) formed in the insulating layer (8) increases substantially from the bottom toward the top of the insulating layer.
Claim 2
Dependent Claim
22 words
A via hole structure as set forth in claim 1, wherein the insulating resin films (2,5) are made of a photosensitive resin.
Claim 3
Dependent Claim
31 words
A via hole structure as set forth in claim 1 or 2, wherein the diameter of the top of the aperture of the via hole (7) is 300 µm or less.
Claim 4
Dependent Claim
17 words
A via hole structure as set forth in any preceding claim, wherein the insulating resin comprises polyimide.
Claim 5
Dependent Claim
28 words
A via hole structure as set forth in any preceding claim, wherein the thickness of the insulating layer (8) is in the range of 2 to 100 µm.
Claim 6
Dependent Claim
23 words
A via hole structure as set forth in any preceding claim and further including a metal film formed in the via hole (7).
Claim 7
Dependent Claim
39 words
A protective film or interlayer insulating film of a printed circuit for high-density mounting, a printed circuit board, a wiring board, or an electronic component, including one or more via hole structures as set forth in any preceding claim.
Claim 8
Dependent Claim
94 words
A process for the formation of a via hole structure in an insulating layer (8) comprising a plurality of insulating resin films (2,5), including the steps of: forming a first insulating resin film (2) and forming a first aperture (4) in the first insulating resin film; and forming a second insulating resin film (5) on the first and forming a second aperture (7) in the second insulating resin film (5) whose centre coincides with that of the first aperture (4); characterised in that the second aperture (7) is smaller than the first aperture (4).
Claim 9
Dependent Claim
18 words
A process according to claim 8, wherein the insulating resin films (2,5) are made of a photosensitive resin.
Claim 10
Dependent Claim
31 words
A process according to claim 8 or 9, wherein the insulating resin films (2,5) are each formed by applying a coating solution of an insulating resin in at least one solvent.
Claim 11
Dependent Claim
20 words
A process according to any of claims 8 to 10, wherein the insulating resin comprises polyimide or a polyimide precursor.
Claim 12
Dependent Claim
29 words
A process according to any of claims 8 to 11, and including the further step of forming a metal film in the via hole (7) by a dry process.
Claim 13
Dependent Claim
27 words
A process according to any of claims 8 to 12, wherein the thickness of the insulating layer (8) is in the range of 2 to 100 µm.
Claim 14
Dependent Claim
43 words
A process according to any of claims 8 to 13, in which the insulating layer (8) is a protective film or an interlayer insulating film of a printed circuit for high-density mounting, a printed circuit board, a wiring board, or an electronic component.
References Cited (Backward Citations)
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