US5312674A
Expired / Lapsed
US
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Low-temperature-cofired-ceramic (LTCC) tape structures including cofired ferromagnetic elements, drop-in components and multi-layer transformer
Assignee: Raytheon Co
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Filing: 1992-07-31
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Granted: 1994-05-17
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Expires: 2012-07-31
Abstract
Abstract A ferromagnetic material (18,20) in ink or tape form is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as low-temperature-cofired-ceramic (LTCC) tape, and is chemically non-reactive therewith. The ferromagnetic material (18,20) is applied to the surfaces of LTCC tape sheets (12,14,16) to form desired elements such as cores for inductors (22) and transformers and magnetic shields. Ferromagnetic vertical interconnects (vias) (54) can be formed by punching holes (56) through tape sheets (46) and filling them with ferromagnetic ink. The tape sheets (12,14,16) and ferromagnetic elements (18,20) are laminated together and cofired to form an integral structure (10). Ferromagnetic and non-magnetic components (114) can be fabricated separately and inserted into cavities (104a, 106a,108a) in tape sheets (104,106,108) prior to cofiring. A multi-layer transformer (250) includes primary (254b, 256b,258b,254d,256d,258d) and secondary (254c,256c,258c) coils, each being formed of vertically aligned, arcuate conductors which are printed on separate tape sheets (254,256,258) and vertically interconnected at their ends to form continuous electrical paths therethrough.
Inventors
- 👤 Carol Haertling
- 👤 Andrew A. Shapiro
- 👤 Charles A. Goodman
- 👤 Ramona G. Pond
- 👤 Robert D. Washburn
- 👤 Robert F. McClanahan
- 👤 Carlos H. Gonzalez
- 👤 David M. Lusher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:30
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/16; H05K1/165; H10; H10W; H10W76/00; H10W76/10; H10W76/12; H10W76/15; H10W76/153; H10W90/00; H05K1/02; H05K1/03; H05K1/0306; H05K1/09; H05K1/092; H05K2201/00; H05K2201/08; H05K2201/083; H05K2201/086; H05K3/00; H05K3/46; H05K3/4611; H05K3/4626; H05K3/4629; H05K3/4688; H10W70/00; H10W70/60; H10W70/67; H10W70/68; H10W70/682; H10W70/685; H10W72/00; H10W72/071; H10W72/072; H10W72/07251; H10W72/20; H10W72/50; H10W72/531; H10W72/5363; H10W72/851; H10W72/874; H10W72/884; H10W90/701; H10W90/731; H10W90/734; H10W90/737; H10W90/751; H10W90/754; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
76 words
A cofired ceramic tape circuit structure, comprising; a plurality of sandwiched sheets of low-temperature-cofired-ceramic (LTCC) tape; and a ferromagnetic element sandwiched between sheets of said tape, said element being formed of a material which is substantially chemically non-reactive with, is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as said tape, wherein said the ferromagnetic material comprises a ferromagnetic oxide, a glass powder (or frit) and an organic binder.
Claim 2
Dependent Claim
76 words
A cofired ceramic tape circuit structure, comprising; a plurality of sandwiched sheets of low-temperature-cofired-ceramic (LTCC) tape; and a ferromagnetic element sandwiched between sheets of said tape, said element being formed of a material which is substantially chemically non-reactive with, is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as said tape, wherein said the ferromagnetic material comprises a ferromagnetic oxide, a glass powder (or frit) and an organic binder.
Claim 3
Dependent Claim
22 words
A structure as in claim 1, in which said material comprises a glass frit having a melting point of approximately 500-650° C.
Claim 4
Dependent Claim
62 words
A structure as in claim 1, in which said material comprises; a ferromagnetic oxide powder; and a glass frit including silicon dioxide (SiO 2 ) and at least one material selected from the group consisting of lead oxide (PbO), bismuth oxide (Bi 2 O 3 ), sodium oxide (Na 2 O), lithium oxide (Li 2 O), and potassium oxide (K 2 O).
Claim 5
Dependent Claim
24 words
A structure as in claim 1, in which said element comprises a vertical interconnect (via) which extends through at least one of said sheets.
Claim 6
Dependent Claim
12 words
A structure as in claim 1, in which said element is flat.
Claim 7
Dependent Claim
32 words
A structure as in claim 1, in which: the structure further comprises an inductor formed between sheets of said tape; and said element is arranged to increase the inductance of the inductor.
Claim 8
Dependent Claim
33 words
A structure as in claim 6, in which: the inductor includes a flat electrical conductor having a predetermined shape; and said element comprises a flat layer which is vertically aligned with said conductor.
Claim 9
Dependent Claim
38 words
A structure as in claim 1, in which: the structure further comprises an electrical component disposed between sheets of said tape; and said element comprises a flat layer which is vertically aligned with and magnetically shields said component.
Claim 10
Dependent Claim
51 words
A ferromagnetic material which is cofirable with and chemically non-reactive with low-temperature-cofired-ceramic (LTCC) tape, comprising: a ferromagnetic oxide; an organic vehicle; and a glass frit comprising constituents selected such that said material is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as said tape.
Claim 11
Dependent Claim
51 words
A ferromagnetic material which is cofirable with and chemically non-reactive with low-temperature-cofired-ceramic (LTCC) tape, comprising: a ferromagnetic oxide; an organic vehicle; and a glass frit comprising constituents selected such that said material is sinterable using a same firing profile as and has approximately the same thermal shrinkage characteristics as said tape.
Claim 12
Dependent Claim
19 words
A material as in claim 9, in which the glass frit has a melting point of approximately 500-650° C.
Claim 13
Dependent Claim
54 words
A material as in claim 10, in which the glass frit comprises silicon dioxide (SiO 2 ) and at least one material selected from the group consisting of lead oxide (PbO), bismuth oxide (Bi 2 O 3 ), sodium oxide (Na 2 O) lithium oxide (Li 2 O) and potassium oxide (K 2 O).
Claim 14
Dependent Claim
27 words
A material as in claim 9, further comprising a solvent in a proportion selected such that said material is in fluid form and has a ink viscosity.
Claim 15
Dependent Claim
24 words
A material as in claim 9, in which said vehicle is selected such that said material is in solid form and has tape flexibility.
Claim 16
Dependent Claim
16 words
A material as in claim 13, in which said material is formed as a tape sheet.
Claim 17
Dependent Claim
19 words
A material as in claim 9, in which the ferromagnetic oxide comprises nickel-zinc ferrite (NiZnFe 3 O 4 ).
Claim 18
Dependent Claim
23 words
A material as in claim 9, in which the ferromagnetic oxide is selected from the group consisting of spinels, including magnetoplumbites and garnets.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-16 | 1997-11-15 | 1998-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-16 | 2001-11-15 | 2002-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-16 | 2005-11-15 | 2006-05-17 | $7700.00 | Window Closed / Lapsed |