US5108958A
Expired / Lapsed
US
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Ceramic composite for electronic applications
Assignee: 3M Co
•
Filing: 1990-03-23
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Granted: 1992-04-28
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Expires: 2010-03-23
Abstract
Abstract Machinable ceramic composites having a low dielectric constant. The composite comprises ceramic bubbles uniformly distributed throughout a ceramic matrix. These composites can be used as ceramic substrates and housings in electronic packaging, and as windows transparent to microwave and millimeter wave radiation.
Inventors
- 👤 Kyung H. Moh
- 👤 Charles D. Hoyle
- 👤 Charles E. Boyer, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:12
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/16; H; H10; H10W; H10W70/00; H10W70/60; H10W70/67; H10W70/69; H10W70/692; H10W76/00; H10W76/10; H10W76/17; H10W76/18; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0306
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
24 words
A composite comprising hollow, thin-walled, refractory, ceramic bubbles having a dielectric constant less than 9, said bubbles uniformly distributed throughout a refractory, ceramic matrix.
Claim 2
Dependent Claim
24 words
A composite comprising hollow, thin-walled, refractory, ceramic bubbles having a dielectric constant less than 9, said bubbles uniformly distributed throughout a refractory, ceramic matrix.
Claim 3
Dependent Claim
19 words
The composite of claim 1, said composite not having been fired at a temperature of at least 1,000° C.
Claim 4
Dependent Claim
18 words
The composite of claim 1, said composite having been fired at a temperature of at lease 1,000° C.
Claim 5
Dependent Claim
29 words
The composite of claim 1, wherein the ceramic matrix is prepared from material selected from the group consisting of aluminum phosphate, alumina, mullite, steatite, forsterite, cordierite, and mixtures thereof.
Claim 6
Dependent Claim
22 words
The composite of claim 1, wherein the ceramic bubbles are selected from the group consisting of aluminum borosilicate, mullite, and mixtures thereof.
Claim 7
Dependent Claim
68 words
The composite of claim 1, wherein the dielectric constant thereof is from about 1.5 to about 6.5 measured from 0.1 to 20 GHz, from about 1.5 to about 6.5 measured at 1 MHz; wherein the dielectric loss factor (ε") is from about 0.001 to 1.0 measured at 0.1 to 20 GHz, and the dissipation factor or loss tangent is from about 0.001 to about 1.0 at 1 MHz.
Claim 8
Dependent Claim
37 words
The article of claim 2, wherein the bubbles are selected from the group consisting of bubbles of aluminum borosilicate, mullite, and mixtures thereof that are unfired or have been fired below the sintering temperature of the composite.
Claim 9
Dependent Claim
24 words
The composite of claim 1, wherein the ratio of the ceramic bubbles to the ceramic matrix ranges from 0.6:1.0 to 1.5:1.0, based on volume.
Claim 10
Dependent Claim
24 words
The composite of claim 1, wherein the ceramic bubbles are incorporated into the ceramic matrix at a concentration of 10 to 90 volume percent.
Claim 11
Dependent Claim
24 words
The composite of claim 9, wherein the ceramic bubbles are incorporated into the ceramic matrix at a concentration of 40 to 70 volume percent.
Claim 12
Dependent Claim
24 words
The composite of claim 10, wherein the ceramic bubbles are incorporated into the ceramic matrix at a concentration of 50 to 60 volume percent.
Claim 13
Dependent Claim
17 words
An article that is transparent to microwaves and to millimeter waves comprising the composite of claim 1.
Claim 14
Dependent Claim
23 words
The composite of claim 1, wherein the thermal expansion coefficient is approximately 4.0×10 -6 /°C. from room temperature (25° C.) to 400° C.
Claim 15
Dependent Claim
61 words
A method of preparing the composite of claim 1, comprising the steps of: (1) providing a refractory ceramic matrix, and refractory ceramic bubbles; (2) mixing the ceramic matrix of step (1) with the ceramic bubbles of step (1) to form a mixture; (3) shaping the mixture of step (2); and (4) firing the mixture of step (3) to form the composite.
Claim 16
Dependent Claim
55 words
A method of preparing the composite of claim 1, comprising the steps of: (1) providing a liquid dispersion comprising a refractory ceramic matrix, refractory ceramic bubbles, and a liquid; (2) drying the mixture of step (1); (3) shaping the mixture of step (2); and (4) firing the mixture of step (3) to form the composite.
Claim 17
Dependent Claim
55 words
A method of preparing the composite of claim 1, comprising the steps of: (1) providing a liquid dispersion comprising a refractory ceramic matrix, refractory ceramic bubbles, and a liquid; (2) shaping the mixture of step (1); (3) drying the mixture of step (2); and (4) firing the mixture of step (3) to form the composite.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-28 | 1995-10-28 | 1996-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-28 | 1999-10-28 | 2000-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-28 | 2003-10-28 | 2004-04-28 | $7700.00 | Window Closed / Lapsed |