Low dielectric glass and fiber glass for electronic applications
Glass compositions are provided that are useful in electronic applications, e.g., as reinforcements in printed circuit board substrates. Reduced dielectric constants are provided relative to E-glass, and fiber forming properties are provided that are more commercially practical than D-glass.
1. A glass composition suitable for fiber forming comprising:
SiO 2
60-68
weight percent;
B 2 O 3
7-12
weight percent;
Al 2 O 3
9-15
weight percent;
MgO
8-15
weight percent;
CaO
0-4
weight percent;
Li 2 O
>0-2
weight percent;
Na 2 O
0-1
weight percent;
K 2 O
0-1
weight percent;
Fe 2 O 3
0-1
weight percent;
F 2
0-1
weight percent;
TiO 2
0-2
weight percent; and
other constituents
0-5
weight percent total.
wherein the Li 2 O content is greater than either the Na 2 O content or the K 2 O content.
2. The composition of claim 1 wherein the CaO content is 0-3 weight percent.
3. The composition of claim 1 wherein the CaO content is 0-2 weight percent.
4. The composition of claim 1 wherein the CaO content is 0-1 weight percent.
5. The composition of claim 1 wherein the MgO content is 8-13 weight percent.
6. The composition of claim 1 wherein the MgO content is 9-12 weight percent.
7. The composition of claim 1 wherein the TiO 2 content is 0-1 weight percent.
8. The composition of claim 1 wherein the B 2 O 3 content is no more than 10 weight percent.
9. The composition of claim 1 wherein the Al 2 O 3 content is 9-14 weight percent.
10. The composition of claim 1 wherein the Al 2 O 3 content is 10-13 weight percent.
11. The composition of claim 1 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 6.7 at 1 MHz frequency.
12. The composition of claim 1 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 6 at 1 MHz frequency.
13. The composition of claim 1 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 5.8 at 1 MHz frequency.
14. The composition of claim 1 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 5.6 at 1 MHz frequency.
15. The composition of claim 1 wherein the constituents are selected to provide a forming temperature T F at 1000 poise viscosity no greater than 1370° C.
16. The composition of claim 1 wherein the constituents are selected to provide a forming temperature T F at 1000 poise viscosity no greater than 1320° C.
17. The composition of claim 1 wherein the constituents are selected to provide a forming temperature T F at 1000 poise viscosity no greater than 1300° C.
18. The composition of claim 1 wherein the constituents are selected to provide a forming temperature T F at 1000 poise viscosity no greater than 1290° C.
19. The composition of claim 15 wherein the constituents are selected to provide a liquidus temperature T L at least 55° C. below the forming temperature.
20. The composition of claim 16 wherein the constituents are selected to provide a liquidus temperature T L at least 55° C. below the forming temperature.
21. The composition of claim 17 wherein the constituents are selected to provide a liquidus temperature T L at least 55° C. below the forming temperature.
22. The composition of claim 18 wherein the constituents are selected to provide a liquidus temperature T L at least 55° C. below the forming temperature.
23. The composition of claim 1 wherein the Li 2 O content is 0.4-2.0 weight percent.
24. The composition of claim 23 wherein the Li 2 O content is greater than the (Na 2 O+K 2 O) content.
25. The composition of claim 1 wherein the (Li 2 O Na 2 O,+K 2 O) content is less than 2 weight percent.
26. The composition of claim 1 wherein the composition contains 0-1 weight percent of BaO and 0-2 weight percent ZnO.
27. The composition of claim 1 wherein the composition contains essentially no BaO and essentially no ZnO.
28. The composition of claim 1 wherein other constituents, if any, are present in a total amount of 0-2 weight percent.
29. The composition of claim 1 wherein other constituents, if any, are present in a total amount of 0-1 weight percent.
30. A glass composition suitable for fiber forming comprising:
B 2 O 3
less than 12
weight percent;
Al 2 O 3
9-15
weight percent;
MgO
8-15
weight percent;
CaO
0-4
weight percent;
SiO 2
60-68
weight percent;
Li 2 O
>0-2
weight percent;
Na 2 O
0-1
weight percent;
K 2 O
0-1
weight percent;
Fe 2 O 3
0-1
weight percent;
F 2
0-1
weight percent;
TiO 2
0-2
weight percent;
wherein the glass exhibits a dielectric constant (D k ) less than 6.7 and forming temperature (T F ) at 1000 poise viscosity no greater than 1370° C. and wherein the Li 2 O content is greater than either the Na 2 O content or the K 2 O content.
31. The composition of claim 30 wherein the CaO content is 0-1 weight percent.
32. A glass composition suitable for fiber forming comprising:
SiO 2
60-68 weight percent
B 2 O 3
7-12 weight percent
Al 2 O 3
9-15 weight percent
MgO
8-15 weight percent
CaO
0-3 weight percent
Li 2 O
0.4-2 weight percent
Na 2 O
0-1 weight percent
K 2 O
0-1 weight percent
Fe 2 O 3
0-1 weight percent
F 2
0-1 weight percent
TiO 2
0-2 weight percent
wherein the glass exhibits a dielectric constant (D k ) less than 5.9 and forming temperature (T F ) at 1000 poise viscosity no greater than 1300° C. and wherein the Li 2 O content is greater than either the Na 2 O content or the K 2 O content.
33. A glass composition suitable for fiber forming consisting essentially of:
SiO 2
60-68 weight percent;
B 2 O 3
7-11 weight percent;
Al 2 O 3
9-13 weight percent;
MgO
8-13 weight percent;
CaO
0-3 weight percent;
Li 2 O
0.4-2 weight percent;
Na 2 O
0-1 weight percent;
K 2 O
0-1 weight percent;
(Na 2 O + K 2 O + Li 2 O)
0-2 weight percent;
Fe 2 O 3
0-1 weight percent
F 2
0-1 weight percent
TiO2
0-2 weight percent
wherein the Li 2 O content is greater than either the Na 2 O content or the K 2 O content.
34. The composition of claim 33 wherein the CaO content is 0-1 weight percent.
35. The composition of claim 34 wherein the B 2 O 3 content is no more than 10 weight percent.
36. A glass composition suitable for fiber forming comprising:
SiO 2
60-68 weight percent;
B 2 O 3
7-10 weight percent;
Al 2 O 3
9-15 weight percent;
MgO
8-15 weight percent;
CaO
0-4 weight percent;
Li 2 O
0-2 weight percent;
Na 2 O
0-1 weight percent;
K 2 O
0-1 weight percent;
Fe 2 O 3
0-1 weight percent;
F 2
0-1 weight percent;
TiO 2
0-2 weight percent; and
other constituents
0-5 weight percent.
37. The composition of claim 36 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 6.7 at 1 MHz frequency.
38. The composition of claim 36 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 6 at 1 MHz frequency.
39. The composition of claim 36 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 5.8 at 1 MHz frequency.
40. The composition of claim 36 wherein the constituents are selected to provide a glass having a dielectric constant (D k ) less than 5.6 at 1 MHz frequency.