Circuit-forming substrate and circuit substrate
AssigneeNitto Denko Corporation
InventorsToshihiko Omote, Yasuhito Funada, Hideyuki Usui, Masanori Ueno, Kazumasa Igarashi
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Abstract
There are provided a circuit-forming substrate comprising a long stainless steel foil having formed on one surface or both surfaces thereof a polyimide resin layer wholly or partially, and a circuit substrate formed by using the circuit-forming substrate, wherein a conductor layer is finely patterned on the circuit-forming substrate. The circuit-forming substrate sufficiently satisfies low cost, high density and high reliability, scarcely causes warping of the substrate itself, and has excellent workability.
Claims4
A process of producing a circuit substrate, comprising:
- (A) providing a polyimide precursor solution comprising a polyimide precursor containing a photosensitive agent on a long stainless steel foil,
- wherein the solution is provided wholly or partially, on one surface or both surfaces, of the foil, and
- (B) further providing on the polyimide resin layer a conductor layer formed by laminating a copper layer via a chromium layer or a titanium layer or directly.
A process of producing a hard disk suspension, comprising:
- (A) providing a polyimide precursor solution comprising a polyimide precursor containing a photosensitive agent on a long stainless steel foil,
- wherein the solution is provided wholly or partially, on one surface or both surfaces, of the foil, and
- (B) further providing on the polyimide resin layer a conductor layer formed by laminating a copper layer via a chromium layer or a titanium layer or directly.
A process of producing a circuit substrate, comprising the steps of:
- providing a polyimide precursor solution comprising a photosensitive polyimide resin containing a photosensitive agent on one surface or both surfaces of a long stainless steel foil,
- drying the polyimide precursor solution to prepare a polyimide precursor layer,
- irradiating the polyimide precursor layer with light through a photomask having a desired pattern,
- developing with a developer,
- heating the remaining polyimide precursor layer to prepare a polyimide resin layer, and
- laminating, on the stainless steel foil exposed by the developing step and the polyimide resin layer, a copper layer directly or via a chromium layer or a titanium layer to provide a conductor layer.
A process of producing a hard disk suspension comprising the steps of:
- providing a polyimide precursor solution comprising a photosensitive polyimide resin containing a photosensitive agent on one surface or both surfaces of a long stainless steel foil,
- drying the polyimide precursor solution to prepare a polyimide precursor layer,
- irradiating the polyimide precursor layer with light through a photomask having a desired pattern,
- developing with a developer, heating the remaining polyimide precursor layer to prepare a polyimide resin layer, and
- laminating, on the stainless steel foil exposed by the developing step and the polyimide resin layer, a copper layer directly or via a chromium layer or a titanium layer to provide a conductor layer.
Dependencies are inferred from the claim text.