Distributed constant circuit board using ceramic substrate material

• US 5,232,765 A
• Filed: 07/22/1991
• Issued: 08/03/1993
• Est. Priority Date: 07/25/1990
• Status: Expired due to Term

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Yamaguchi, Hirofumi, Yano, Shinsuke, Hirai, Takami
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): MULVANEY, ELIZABETH EVANS
• Application Number:
  US07/733,642
• Time in Patent Office: 743 Days
• Field of Search: 428/195, 428/209, 428/210, 428/323, 428/325, 428/332, 428/402, 428/432, 428/433, 428/457, 428/901
• US Class Current: 428/195.1
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01P 1/203 Strip line filters
• CPC Class Codes: H01P 3/088 Stacked transmission lines
• CPC Class Codes: H05K 1/024 Dielectric details, e.g. changing the dielectric material around a transmission line
• CPC Class Codes: H05K 1/0306 Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles
• CPC Class Codes: H05K 3/4611 by laminating two or more circuit boards H05K3/4652 takes precedence
• CPC Class Codes: H05K 3/4629 laminating inorganic sheets comprising printed circuits, e.g. green ceramic sheets
• CPC Class Codes: Y10S 428/901 Printed circuit
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/31678 : Of metal

Abstract

A distributed constant circuit board including a ceramic substrate, and at least one conductor pattern which is carried by the ceramic substrate and which forms a resonance circuit, an inductor, a capacitor or strip transmission line. The conductor pattern has an electrically conductive composition whose major component is selected from the group consisting of Ag, Au and Cu, and which has a sheet resistivity not higher than 10 mΩ per square. The conductor is formed by co-firing with the ceramic substrate, so that the conductor pattern is incorporated in the substrate. The ceramic substrate is formed principally of a ceramic composition which gives the resonance circuit a resonance frequency whose temperature coefficient is held within a range between -30 ppm/° C. and +100 ppm/° C.

Claims

1. A distributed constant circuit board, comprising:

a ceramic substrate consisting essentially of a ceramic composition including at least 5% by weight of TiO₂ powder, wherein particles of said TiO₂ powder are dispersed in said ceramic substrate; and

a microwave integrated circuit buried in said ceramic substrate, said microwave integrated circuit forming at least one of a resonance circuit, an inductor, a capacitor and a strip transmission line and having a major component selected from the group consisting of Ag, Au and Cu, said microwave integrated circuit having a sheet resistivity not higher than 10 mΩ

per square;

wherein

said ceramic composition of said ceramic substrate yields a temperature coefficient between -30 ppm/°

C. and +100 ppm/°

C. of such a resonance circuit, said microwave integrated circuit is co-fired with a green sheet of said ceramic substrate, and a sintering temperature of the ceramic substrate is not higher than 1100°

C.

2. A distributed constant circuit board of claim 1, wherein said TiO₂ powder is calcined so as to give a BET specific surface area not larger than 2 m² /g.

3. A distributed constant circuit board of claim 1, wherein said ceramic composition comprises a mixture of an amorphous or crystallized glass powder and said TiO₂ powder, said amorphous or crystallized glass powder having a dielectric constant not higher than 20.

4. A distributed constant circuit board according to claim 3, wherein said ceramic composition further comprises a filler in the form of a powder selected from the group consisting of:

alumina;

mullite;

cordierite, forsterite;

quartz;

quartz glass;

zircon;

zirconia; and

RE₂ Ti₂ O₇ wherein RE is one or more rare earth elements, said filler having a dielectric constant not higher than 50.

5. A distributed constant circuit board of claim 1, wherein said ceramic composition comprises a mixture of a TiO₂ powder, and said ceramic material selected from the group consisting of:

boric acid;

an oxide of alkaline earth metal; and

silicic acid.

6. A distributed constant circuit board of claim 1, wherein said major component of said microwave integrated circuit is selected from the group consisting of:

Ag;

Ag-Pt alloy;

Ag-Pd alloy;

Ag-Pt-Pd alloy;

Cu;

Cu-based alloy;

Au;

Au-Pt alloy;

Au-Pd alloy; and

Au-Pt-Pd alloy.