EP0502614A2
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Thin film circuit substrate and processes for its manufacture
Assignee: Fujitsu Ltd
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Filing: 1992-02-06
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Granted: —
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Expires: 2012-02-06
Abstract
Abstract A thin film circuit substrate comprising multilayer conductor layers (1,4) formed via insulating layers (2,3), wherein a signal transmission path (1) in at least one of the conductor layers is embedded in a low dielectric constant insulator (2), and the low dielectric constant insulator (2) is embedded in an insulator layer (3) with a good adhesiveness. The thin film circuit substrate has a low dielectric constant, and thus an improved signal propagation velocity, but since the low dielectric constant insulator (2) which intrinsically has a low adhesiveness, is entirely surrounded by the insulator layer (3) with good adhesiveness the interlayer adhesiveness is not lowered overall.
Inventors
- 👤 Shuji c/o Fujitsu Limited Takeshita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 20:53
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/0213; H05K1/0237; H05K1/024; H10; H10W; H10W70/00; H10W70/60; H10W70/611; H10W70/62; H10W70/63; H10W70/635; H10W70/67; H10W70/69; H10W70/695; H05K2201/00; H05K2201/01; H05K2201/0183; H05K2201/0187; H05K2201/0195; H05K2201/07; H05K2201/0707; H05K2201/0715; H05K2203/00; H05K2203/11; H05K2203/1184; H05K3/00; H05K3/0011; H05K3/0017; H05K3/0041; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/31504; Y10T428/31678; Y10T428/31681
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
70 words
A thin film circuit substrate comprising multilayer conductor layers (4,10) formed via insulating layers (2,3), with a signal transmission path (1) embedded in the insulating layers (3) between the conductor layers (4,10) characterised in that the signal transmission path (1) is substantially encircled by a low dielectric constant insulator (2), and in that the low dielectric constant insulator (2) is surrounded by an insulator layer (3) with a good adhesiveness.
Claim 2
Dependent Claim
50 words
A substrate as set forth in claim 1, wherein the signal transmission path (1) is supported by the insulator layer (3) with a good adhesiveness in an undercut state and surrounded by the low dielectric constant insulator (2) except for a portion supported by the insulator layer with good adhesiveness.
Claim 3
Dependent Claim
24 words
A substrate as set forth in claim 1, wherein the signal transmission path (1) is entirely surrounded by the low dielectric constant insulator (2).
Claim 4
Dependent Claim
30 words
A substrate as set forth in any one of the preceding claims, wherein the low dielectric constant insulator (2) comprises a fluorinated polyimide, an amorphous fluoropolymer or a perfluorinated polyalkylamine.
Claim 5
Dependent Claim
181 words
A process for the manufacture of a thin film circuit substrate as claimed in claim 1, comprising the steps of: eliminating, by an isotropic etching means, a surface layer of a first insulator layer (3) with a good adhesiveness, and having a signal transmission path (1) formed on the surface thereof, except for at least a portion supporting the signal transmission path in an undercut state, and then coating the entire surface of the thus etched first insulator layer with a good adhesiveness on which the signal transmission path (1) is formed with a low dielectric constant insulator (2); and subsequently eliminating, by etching, the low dielectric constant insulator (2), except for the circumference of the signal transmission path (1), to form a desired pattern so that the signal transmission path is surrounded by the low dielectric constant insulator, and then coating the entire surface of the thus etched first insulator (3) on which the signal transmission path (1) and the low dielectric constant insulator pattern (2) are formed with a layer (3) of a second insulator with a good adhesiveness.
Claim 6
Dependent Claim
201 words
A process for the manufacture of a thin film circuit substrate as claimed in claim 1, comprising the steps of: eliminating, by etching, a first low dielectric constant insulator layer (2) formed on a first insulator layer (3) with a good adhesiveness to form a desired pattern; forming a desired metal pattern of a signal transmission path (1) on the surface of the first low dielectric constant layer pattern (2), and then coating the entire surface of the first insulator layer (3) with a good adhesiveness on which the first low dielectric constant insulator pattern (2) and the metal pattern (1) are formed with a second low dielectric constant insulator layer (2′); and eliminating, by etching, the second low dielectric constant insulator layer (2′) to form a pattern corresponding to the first low dielectric constant insulator pattern (2) so that the metal pattern (1) is positioned between and surrounded by the first and second low dielectric constant insulator pattern layers, and then coating the entire surface of the first insulator layer (3) on which the first and second low dielectric constant insulator patterns containing the metal pattern are formed with a layer (3) of a second insulator with a good adhesiveness.
Claim 7
Dependent Claim
185 words
A process for the manufacture of a thin film circuit substrate as claimed in claim 1, comprising the steps of: forming a first low dielectric constant insulator layer (2) on a surface of a first insulator layer (3) with a good adhesiveness; forming a desired metal pattern of a signal transmission path (1) on the surface of the first low dielectric constant insulator layer, and then coating the entire surface of the first low dielectric constant insulator layer (2) on which the metal pattern (1) is formed with a second low dielectric constant insulator layer (3); and eliminating, by etching, the first and second low dielectric constant insulator layers (2) (2′) to form a pattern such that the metal pattern (1) is positioned between and surrounded by the first and second low dielectric constant insulator pattern layers, and then coating the entire surface of the first insulator layer (3) with a good adhesiveness on which the first and second low dielectric constant insulator patterns (2) (2′) containing the metal pattern (1) are formed with a layer (3) of a second insulator with a good adhesiveness.
References Cited (Backward Citations)
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