Low loss glass-ceramic materials, method of making same and electronic packages including same
A glass-ceramic is provided having a thermal expansion coefficient in a range of 3-6 ppm/° C., a dielectric constant that is less than 5 and a Quality factor Q of at least 400. The glass-ceramic consists essentially of SiO 2 in a range of 45-58 wt %, Al 2 O 3 in a range of 10-18 wt % and MgO in a range of 10-25 wt %. A method of making the glass-ceramic is also provided. Further, an electronic package is also provided, including a base member and a glass-ceramic substrate bonded to the base member.
1. A glass-ceramic material consisting essentially of SiO 2 in a range of 45-58 wt %, Al 2 O 3 in a range of 10-18 wt %, MgO in a range of 10-25 wt % and B 2 O 3 present in an amount up to 10 wt %, said glass-ceramic material having a thermal expansion coefficient in a range of 3-6 ppm/° C., a dielectric constant of less than 5 and a Quality factor (Q) of at least 400.
2. The glass-ceramic material of claim 1 , further including at least one of P 2 O 5 in an amount up to 4 wt %, and GeO 2 in an amount up to 10 wt %.
3. The glass-ceramic material of claim 1 , wherein said glass-ceramic material further includes an additive that is added as a particulate after said glass-ceramic material is formed and pulverized into a powder, said additive comprising at least one material selected form the group consisting of crystalline silica, a material having a high thermal expansion coefficient and a main phase of crystalline silica, cordierite, fused silica and a borosilicate glass.
4. The glass-ceramic material of claim 3 , wherein said additive comprises 1-15 wt % crystalline silica.
5. The glass-ceramic material of claim 3 , wherein said additive comprises 4-12 wt % of a borosilicate glass.
6. The glass-ceramic material of claim 3 , wherein said additive comprises 1-15 wt % of a material consisting essentially of 50-55 wt % SiO 2 , 12-18 wt % Al 2 O 3 , 10-18 wt % MgO and 4-16 wt % ZnO and having a crystalline silica main crystal phase.
7. An electronic package comprising:
a base member; and
a glass-ceramic substrate bonded to said base member, said glass-ceramic substrate consisting essentially of SiO 2 in a range of 45-58 wt %, Al 2 O 3 in a range of 10-18 wt %, MgO in a range of 10-25 wt % and B 2 O 3 present in an amount up to 10 wt %, said glass-ceramic substrate having a thermal expansion coefficient in a range of 3-6 ppm/° C., a dielectric constant of less than 5 and a Quality factor (Q) of at least 400.
8. The electronic package of claim 7 , further comprising a bonding layer interposed between said base member and said glass-ceramic substrate.
9. The electronic package of claim 8 , wherein said bonding layer comprises one of a solder and a bond glass.
10. The electronic package of claim 7 , wherein said glass-ceramic material further includes an additive that is added as a particulate after said glass-ceramic material is formed and pulverized into a powder, said additive comprising at least one material selected form the group consisting of crystalline silica, a material having a high thermal expansion coefficient and a main phase of crystalline silica, cordierite, fused silica and a borosilicate glass.
11. A substrate for an electronic package comprising the glass-ceramic material of claim 1 .