Compositions: ceramic – Ceramic compositions – Devitrified glass-ceramics
Reexamination Certificate
1999-11-12
2002-02-19
Sample, David (Department: 1755)
Compositions: ceramic
Ceramic compositions
Devitrified glass-ceramics
C501S008000, C501S032000, C501S070000, C501S072000, C501S073000, C156S089110
Reexamination Certificate
active
06348424
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a low-temperature calcined inorganic composition which can be simultaneously calcined with a low-resistance conductor such as Au, Ag and Cu. In particular, this invention relates to a low-temperature calcined glass ceramic which has a low dielectric constant and a low dielectric loss at a frequency in microwave and millimeter-wave ranges and which is suitable as an insulating layer in a multilayer wiring board for a microwave or millimeter-wave circuit.
2. Description of the Prior Art
A low-temperature calcined glass ceramic multilayer wiring board has been developed as an effective measure for improving performance of an electronic equipment because it permits a multilayered wiring, a higher density with a fine wiring and a miniaturized wiring; a low-resistance conductor such as Au, Ag and Cu can be selected as a wiring material; and the dielectric constant of an insulating layer may be lowered to allow a signal to be quickly transferred. In addition, a radio-frequency analogue circuit can be electromagnetically shielded because of a contact pattern of conductor plane and a high-density layout of cavity structures and via holes. Therefore, various elements such as a transmitter and receiver module and a DC or RF circuit may be integrated, which leads to miniaturization and performance improvement. Furthermore, a module mounted with multiple MMICs may be miniaturized and improved in its performance. Thus, the wiring board has been developed for use in, for example, a module for a communication device including a high-frequency analogue circuit in a microwave range.
In the field of high-frequency communication devices such as those for mobile communication and satellite communication, it is expected to use a system involving a super high-frequency range such as microwave and millimeter wave in a variety of applications. In the field of communication devices comprising a high-frequency analogue circuit, it is expected to use systems involving not only a microwave band but also a millimeter wave band, a further higher frequency range. In a module equipped with such an analogue circuit involving a super high-frequency range, it is essential to reduce a signal transmission loss. Therefore, for a glass ceramic type of multilayer wiring board, it is needed to minimize a dielectric loss of an insulating material and a resistance of a conductor.
SUMMARY OF THE INVENTION
An object of this invention is to provide a low-temperature calcined glass ceramic which can be calcined at a temperature below 1000° C., i.e., can be calcined simultaneously with a low-resistance conductor such as Au, Ag and Cu for internal mounting or multilayering, and which is suitable for an insulating layer in a multiple layer wiring board equipped with a high-frequency analogue circuit with a low dielectric constant and a low dielectric loss at a frequency within microwave and millimeter wave ranges.
We have intensely investigated a variety of glass compositions in an attempt to solve the problems in a conventional low-temperature calcined glass ceramic, and have found that an SiO
2
—B
2
O
3
—CaO—Al
2
O
3
glass with a certain range of composition has a low glass softening point, can be calcined at a temperature below 1000° C. as a composite with various ceramics and is crystallized during a calcination process to exhibit a low dielectric constant and a low dielectric loss, and that an SiO
2
—CaO—Al
2
O
3
glass with a certain range of composition, as a composite with various ceramics or alone, can be calcined at a temperature below 1000° C. and is crystallized during a calcination process to exhibit a low dielectric constant and a low dielectric loss.
This invention provides:
(1) A low-temperature calcined glass ceramic consisting of 50 to 100 wt % of glass powder and 0 to 50 wt % of ceramic powder, where the glass powder has an oxide-converted composition of 35 to 65 wt % of SiO
2
, 5 to 35 wt % of B
2
O
3
, 2 to 20 wt % of CaO, 5 to 25 wt % of Al
2
O
3
where the ratio of CaO to Al
2
O
3
is 1/1 to 1/2.5, 0.5 to 5 wt % of TiO
2
, 0.5 to 5 wt % of ZrO
2
, 0.5 to 5 wt % of ZnO, 0 to 5 wt % of MgO, 0 to 5 wt % of SrO, 0 to 5 wt % of BaO and 0 to 1 wt % of a group 1A element oxide; and is densified during calcination at 850 to 1000° C.;
(2) A low-temperature calcined glass ceramic described in (1), where the group 1A element oxide is at least one selected from the group consisting of Na
2
O, K
2
O and Li
2
O;
(3) A low-temperature calcined glass ceramic described in (1) or (2), where alumina is precipitated during the calcination process;
(4) A low-temperature calcined glass ceramic described in (1) or (2), where CaAl
2
SiO
6
is precipitated during the calcination process;
(5) A low-temperature calcined glass ceramic described in any of (1) to (4), where the ceramic powder is at least one selected from the group consisting of alumina, silica, mullite, cordierite and forsterite;
(6) A low-temperature calcined glass ceramic which is an SiO
2
—CaO—Al
2
O
3
glass having an oxide-converted composition of 10 to 45 wt % of SiO
2
, 20 to 50 wt % of CaO, 20 to 45 wt % of Al
2
O
3
, 0.1 to 5 wt % of MgO, 0.1 to 5 wt % of SrO, 0.1 to 5 wt % of BaO, 0.1 to 5 wt % of TiO
2
, 0.1 to 5 wt % of ZnO, 0.1 to 5 wt % of ZrO
2
and 0 to 3 wt % of a group 1A element oxide; and is densified during calcination at 800 to 1000° C.;
(7) A low-temperature calcined glass ceramic which is a composite comprising ceramic particles dispersed in an SiO
2
—CaO—Al
2
O
3
glass having an oxide-converted composition of 10 to 45 wt % of SiO
2
, 20 to 50 wt % of CaO, 20 to 45 wt % of Al
2
O
3
, 0.1 to 5 wt % of MgO, 0.1 to 5 wt % of SrO, 0.1 to 5 wt % of BaO, 0.1 to 5 wt % of TiO
2
, 0.1 to 5 wt % of ZnO, 0.1 to 5 wt % of ZrO
2
and 0 to 3 wt % of a group 1A element oxide; and is densified during calcination at 800 to 1000° C.;
(8) A low-temperature calcined glass ceramic described in (6) or (7), where the group 1A element oxide is at least one selected from the group consisting of Na
2
O, K
2
O and Li
2
O;
(9) A low-temperature calcined glass ceramic described in (7) or (8), where the rate of the ceramic particles in the composite is 10 to 50 wt %;
(10) A low-temperature calcined glass ceramic described in any of (7) to (9), where the ceramic particles are particles of at least one selected from Al
2
O
3
(alumina), SiO
2
(silica), Mg
2
Al
4
Si
5
O
18
(Cordierite), Mg
2
SiO
4
(Forsterite) and Al
6
Si
2
O
13
(Mullite);
(11) A low-temperature calcined glass ceramic described in any of (6) to (10), where at least one of the crystals of CaAl
2
SiO
6
, Ca
3
Si
2
O
7
(Rankinite), CaSiO
3
(Wollastonite) and Al
6
Si
2
O
13
(Mullite) is precipitated;
(12) A process for manufacturing a low-temperature calcined glass ceramic, comprising the steps of:
(A) film deposition where a green sheet is prepared from a mixed powder consisting of 50 to 100 wt % of SiO
2
—CaO—Al
2
O
3
glass powder and 0 to 50 wt % of ceramic powder;
(B) lamination where the green sheet is piled up and is then hot-pressed to give a laminate;
(C) calcination where the laminate from the above step is calcined at a temperature of 800 to 1000° C. to give a sintered compact, characterized in that the glass has an oxide-converted composition of 10 to 45 wt % of SiO
2
, 20 to 50 wt % of CaO, 20 to 45 wt % of Al
2
O
3
, 0.1 to 5 wt % of MgO, 0.1 to 5 wt % of SrO, 0.1 to 5 wt % of BaO, 0.1 to 5 wt % of TiO
2
, 0.1 to 5 wt % of ZnO, 0.1 to 5 wt % of ZrO
2
and 0 to 3 wt % of a group 1A element oxide;
(13) A process for manufacturing a low-temperature calcined glass ceramic described in (12), where the group 1A element oxide is at least one selected from the group consisting of Na
2
O, K
2
O and Li
2
O;
(14) A process for manufacturing a low-temperature calcined glass ceramic described in (12) or (13), where the ceramic particles are particles of at least one selected from Al
2
O
3
(Alumina), SiO
2
(Silica), Mg
2
Al
4
Si
5
O
18
(Cordierite), Mg
2
SiO
4
(Forsterite), CaAl
2
SiO
7
, Ca
3
Si
2
O
7
(Rankinite), CaSiO
3
(Wollas
Hazeyama Ichiro
Ikuina Kazuhiro
NEC Corporation
Sample David
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