Printed circuit boards and cards having buried thin film capacitors and processing techniques for fabricating said boards and cards

• US 5,027,253 A
• Filed: 04/09/1990
• Issued: 06/25/1991
• Est. Priority Date: 04/09/1990
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lauffer, John M., Schumacher, Richard A.
• Primary Examiner(s): GRIFFIN, DONALD
• Application Number:
  US07/506,640
• Time in Patent Office: 442 Days
• Field of Search: 361/386, 361/320, 361/321, 361/397-401, 174/68.5, 29/25.42, 501/136-138, 357/51
• US Class Current: 361/321.4
• CPC Class Codes: H05K 1/162 incorporating printed capacitors
• CPC Class Codes: H05K 2201/0175 Inorganic, non-metallic layer, e.g. resist or dielectric for printed capacitor
• CPC Class Codes: H05K 2201/0179 Thin film deposited insulating layer, e.g. inorganic layer for printed capacitor
• CPC Class Codes: H05K 2201/0317 Thin film conductor layer; Thin film passive component
• CPC Class Codes: H05K 2201/0355 Metal foils
• CPC Class Codes: H05K 2201/09309 Core having two or more power planes; Capacitive laminate of two power planes
• CPC Class Codes: H05K 3/429 Plated through-holes specially for multilayer circuits, e.g. having connections to inner circuit layers
• CPC Class Codes: H05K 3/4611 by laminating two or more circuit boards H05K3/4652 takes precedence
• CPC Class Codes: Y10S 257/916 Narrow band gap semiconductor material, <<1ev
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

Disclosed is a multilayer circuit package having a buried thin film capacitor. The circuit package includes at least a power core, a ground core, a first signal core, a second signal core, and the integral, buried, thin film capacitor. The integral, buried, thin film capacitor serves to capacitively couple the first and second signal cores. Structurally, the first signal core includes at least one first wire that terminates in at least one first electrode, while the second signal core includes at least one second wire that terminates in at least one second electrode. At least a portion of the first electrode overlays at least a portion of the first electrode overlays at least a portion of the second electrode and is separated therefrom by a thin film of a dielectric material. The first electrode, the second electrode, and the thin film of dielectric material define the integral buried capacitor. The thin film capacitor is prepared by thin film methodology, with epitaxial deposition of the dielectric.

Claims

1. A multilayer microelectronic circuit package including:

(1) an integral, thin film, buried capacitor comprising;

(a) a first signal core comprising at least one first thin film copper wire having at least one first thin film copper electrode;

(b) a second signal core comprising at least one second thin film copper wire having at least one second thin film copper electrode, at least a portion of said first thin film copper electrode overlying at least a portion of said second thin film copper electrode; and

(c) an epitaxial thin film of a dielectric material between said first copper electrode and said second copper electrode;

said thin film first copper electrode, said thin film second copper electrode, and said thin film of dielectric material define the integral buried thin film capacitor capacitively coupling said thin film signal cores within said multilayer circuit package; and

(2) an integrated circuit chip bonded to said multilayer circuit package and electrically interconnected to one of said capacitively coupled thin film signal cores.

2. The multilayer microelectronic circuit package of claim 1 wherein one of said thin film signal cores is at ground potential.

3. The multilayer microelectronic circuit package of claim 1 wherein the thin film dielectric is a ceramic chosen from the group consisting of calcium titanate, barium titanate, aluminum oxide, berylium oxide, and aluminum nitride.

4. The multilayer microelectronic circuit package of claim 3 wherein the thin film ceramic dielectric is a reactively sputtered ceramic.

5. A multilayer microelectronic circuit package including:

(1) an integral, thin film, buried capacitor comprising;

(a) a first signal core comprising at least one first thin film copper wire having at least one first thin film copper electrode;

(b) a second signal core comprising at least one second thin film copper wire having at least one second thin film copper electrode, at least a portion of said first thin film copper electrode overlying at least a portion of said second thin film copper electrode; and

(c) a thin film of a dielectric material between said first copper electrode and said second copper electrode, said thin film of a dielectric material being a reactively sputtered thin film of a ceramic dielectric;

one of said thin film copper signal cores being at ground potential;

said thin film first copper electrode, said thin film second copper electrode, and said thin film of dielectric material define the integral buried thin film capacitor capacitively coupling said thin film signal cores within said multilayer circuit package; and

(2) an integrated circuit chip bonded to said multilayer circuit package and electrically interconnected to one of said capacitively coupled thin film signal cores.

6. A multilayer microelectronic circuit package including:

(1) an integral, thin film, buried capacitor comprising;

(a) a first signal core comprising at least one first thin film copper wire having at least one first thin film copper electrode;

(b) a second signal core comprising at least one second thin film copper wire having at least one second thin film copper electrode, at least a portion of said first thin film copper electrode overlying at least a portion of said second thin film copper electrode; and

(c) a thin film of a dielectric material between said first copper electrode and said second copper electrode, said thin film of a dielectric material being a reactively sputtered thin film of a ceramic dielectric chosen from the group consisting of calcium titanate, barium titanate, aluminum oxide, berylium oxide, and aluminum nitride;

one of said thin film copper signal cores being at ground potential;

said thin film first copper electrode, said thin film second copper electrode, and said thin film of dielectric material define the integral buried thin film capacitor capacitively coupling said thin film signal cores within said multilayer circuit package; and

(2) an integrated circuit chip bonded to said multilayer circuit package and electrically interconnected to one of said capacitively coupled thin film signal cores.

7. A method of fabricating a multilayer circuit package comprising a first signal core, a second signal core, and integral buried thin film capacitor means capacitively coupling said first and second signal cores, which method comprises:

(a) circuitizing said first signal core on a dielectric substrate to form an electrode;

(b) reactively sputtering a thin film of dielectric chosen from the group consisting of calcium titanate, barium titanate, aluminum oxide, berylium oxide, and aluminum nitride atop said electrode of the circuitized first signal core; and

(c) circuitizing said second signal core atop said thin film of dielectric to form an electrode thereon.

8. The method of claim 7 comprising forming said first and second signal cores of a metallic conductor chosen from the group consisting of Cu, Al, and Ag.

9. The method of claim 8 comprising forming said first and second signal cores of Cu.

10. The method of claim 7 comprising depositing said first conductor to an electrode thickness of from about 100 Angstroms to about 100 microns thick.

11. The method of claim 7 comprising depositing the dielectric thin film to a thickness of from about 100 Angstroms to about 10 microns.