Claims
- 1. A process for fabricating a rigid-flexible circuit board comprising:
- (a) providing at least one core which comprises a dielectric substrate and at least one conductive layer located on said dielectric substrate;
- (b) providing at least one sub-composite which comprises a polyimide and a rigid dielectric substrate adjacent said at least one conductive layer and in both the rigid and flexible segments of said circuit board;
- (c) providing a release layer adjacent said at least one sub-composite in a location to correspond to the desired flexible segment of said circuit board;
- (d) providing at least one rigid bonding layer located adjacent said at least one sub-composite and at the rigid segments of said board but not at the flexible segments of said board;
- (e) providing a second conductive layer adjacent said at least one rigid bonding layer to thereby form a composite;
- (f) laminating said composite;
- (g) removing portions of said second conductive layer that correspond to the flexible segment of said circuit board; and,
- (h) then removing said release layer to thereby provide said rigid-flexible circuit board.
- 2. The process of claim 1 wherein said dielectric substrate is a reinforced epoxy composition or polyimide film.
- 3. The process of claim 1 wherein said dielectric substrate is a flexible substrate.
- 4. The process of claim 3 wherein said flexible substrate comprises a combination of at least one layer of a polyimide film and at least one layer of an epoxy composition and wherein said epoxy composition contacts said at lest one conductive layer.
- 5. The process of claim 4 wherein said polyimide is obtained from biphenyltetracarboxylic dianhydride and diamine.
- 6. The process of claim 2 wherein said polyimide is obtained from biphenyltetracarboxylic dianhydride and a diamine.
- 7. The process of claim 1 wherein the polyimide of said subprocess is obtained from biphenyltetracarboxylic dianhydride and diamine; the rigid dielectric substrate of said subprocess is an epoxy composition wherein said epoxy composition contacts said conductive layer of said core.
- 8. The process of claim 1 wherein said release layer comprises a metal substrate coated with a fluorinated polymer.
- 9. The process of claim 8 wherein said metal substrate is copper.
- 10. The process of claim 1 wherein said rigid bonding layers are reinforced epoxy compositions.
- 11. The process of claim 10 wherein the thickness of said rigid bonding layers is substantially equal to the thickness of said release layer.
- 12. The process of claim 1 wherein said second conductive layer is copper.
- 13. The process of claim 1 wherein said composite comprises a plurality of at least 3 cores with interim release layers and rigid bonding layers.
Parent Case Info
This is a divisional application of Ser. No. 07/913,101, filed on Jul. 14, 1992, now U.S. Pat. 5,288,542.
US Referenced Citations (22)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0427702A2 |
May 1991 |
EPX |
52-146489 |
Dec 1977 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Brochure from Upilex on polyimide films for elec. circuitry. |
IBM Disclosure Bulletin vol. 28, No. 12, May 1986. |
Divisions (1)
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Number |
Date |
Country |
Parent |
913101 |
Jul 1992 |
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