# US 4,396,900 A · Thin film microstrip circuits

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- Number: US 4,396,900 A
- Document ID: US4396900A
- Status: Granted
- Kind: A
- Application number: 06/355,831
- Filed: 1982-03-08
- Granted: 1983-08-02
- Earliest claimed: 1982-03-08
- Assignees: The United States of America as represented by the Secretary of the Navy
- Inventors: Ronald D. Hall
- Web page: https://patentgrep.com/patent/US4396900A

## CPC

- H05K 3/388: {by the use of a metallic or inorganic thin film adhesion layer}
- H10D 86/85: characterised by only passive components
- H05K 1/0237: {High frequency adaptations (H05K1/0216 takes precedence)}
- Y10T 29/49099: Coating resistive material on a base
- Y10T 428/12438: Composite
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A four layer thin film metallization system is comprised of layers of tantalum, chromium, copper and gold and is useful in high resolution, low loss microstrip circuits. The metallization system is compatible with lead-tin solder and, in addition, provides low insertion losses at X-band frequencies.

## Claims

### Claim 1

A thin film microstrip circuit having low insertion loss at X-band frequency and being highly solderable with lead-tin solder comprising,
a non-metallic substrate,
a layer of tantalum fused onto said substrate,
a layer of chromium having a thickness of about 200 Angstroms fused onto said layer of tantalum,
a layer of copper having a thickness of about 50,000 Angstroms fused onto said layer of chromium, and
a layer of gold having a thickness of about 7,000 Angstroms fused onto said layer of copper.