Composition for ceramic substrate, ceramic substrate, process for producing ceramic substrate and glass composition

1. A ceramic substrate composition comprising a glass represented by aB 2 O 3 -bRe 2 O 3 -cZnO in which Re is a rare earth element which is at least one element selected from the group consisting of lanthanum and neodymium and the molar amounts a+b+c=1; and wherein the molar amounts (a, b, and c) fall within a region defined in a ternary composition diagram by Point A (0.4, 0.595, 0.005), Point B (0.4, 0.25, 0.35), Point C (0.52, 0.01, 0.47), Point D (0.9, 0.005, 0.095), and Point E (0.9, 0.09, 0.01) or on the lines connection the Points, at least one oxide selected from the group consisting of aluminum oxide and titanium oxide in an amount of 50% or less by weight of the total amount, and a mixed oxide ceramic material including at least one crystal phase selected from the group consisting of ReBO 3 , Re 3 BO 6 , Re(B 2 O 3 ) 3 and ReB 3 O 6 .

2. The ceramic substrate composition according to claim 1 , wherein the mixed oxide ceramic material is calcined dB 2 O 3 -eRe 2 O 3 in which the molar ratio d/e=1/3 to 3/1.

3. The ceramic substrate composition according to claim 2 , wherein the mixed oxide ceramic material further contains ZnO.

4. The ceramic substrate composition according to claim 1 , wherein the content of the mixed oxide ceramic material is 20% to 90% by weight of the total amount of the glass and the mixed oxide ceramic material.

5. The ceramic substrate composition according to claim 1 , further comprising a crystallization glass that can precipitate at least one crystal phase selected from the group consisting of ReBO 3 , Re 3 BO 6 , Re(B 2 O 3 ) 2 and ReB 3 O 6 .

6. The ceramic substrate composition according to claim 5 , wherein the crystallization glass is represented by gB 2 O 3 -hRe 2 O 3 -iZnO in which g+h+i=1 and the molar amounts g, h, and i fall within a region defined in a ternary composition diagram by Point F (0.4, 0.595, 0.005), Point G (0.4, 0.25, 0.35), Point H (0.52, 0.01, 0.47), Point I (0.9, 0.005, 0.095), and Point J (0.9, 0.09, 0.01) or on the lines connected those Points.

7. The ceramic substrate composition according to claim 5 , wherein the content of the crystallization glass is 20% to 90% by weight of the total amount of the glass and the crystallization glass.

8. The ceramic substrate composition according to claim 1 , further comprising, in addition to the rare earth oxide of said glass, a rare earth oxide comprising Re 2 O 3 .

9. A ceramic substrate comprising precipitated ReBO 3 and/or ReB 3 O 6 as a main crystal phase, the ceramic substrate being produced by the process of providing a predetermined shaped ceramic substrate composition comprising a glass represented by aB 2 O 3 -bRe 2 O 3 -cZnO in which Re is a rare earth element, a+b+c=1, and the molar amounts a, b, and c fall within a region defined in a ternary composition diagram by Point A (0.4, 0.595, 0.005), Point B (0.4, 0.25, 0.35), Point C (0.52, 0.01, 0.47), Point D (0.9, 0.005, 0.095), and Point B (0.9, 0.09, 0.01) or on the lines connecting those Points; and firing the shaped ceramic substrate composition.

10. The ceramic substrate according to claim 9 , wherein the shaped product fired is a laminate of comprising a plurality of layers comprising the glass.

11. The ceramic substrate according to claim 10 , having a patterned conductor comprising at least one metal selected from the group consisting of silver and copper on a layer.

12. A method for producing a ceramic substrate providing a shaped product which is a laminate comprising a plurality of layers comprising a glass represented by aB 2 O 3 -bRe 2 O 3 -cZnO in which Re is a rare earth element, a+b+c=1, and the molar amounts a, b, and c fall within a region defined in a ternary composition diagram by Point A (0.4, 0.595, 0.005), Point B (0.4, 0.25, 0.35), Point C (0.52, 0.01, 0.47), Point D (0.9, 0.005, 0.095), and Point E (0.9, 0.09, 0.01) or on the lines connecting those Points; and firing the shaped product.

13. The method for producing a ceramic substrate according to claim 12 , further comprising forming a patterned conductor comprising at least one metal selected from the group consisting of silver and copper on at least one of the layers.

14. A ceramic substrate composition comprising a glass represented by aB 2 O 3 -bRe 2 O 3 -cZnO in which Re is a rare earth element which is at least one element selected from the group consisting of lanthanum and neodymium and the molar amounts a+b+c=1; and wherein the molar amounts (a, b, and c) fall within a region defined in a ternary composition diagram by Point A (0.4. 0.595, 0.005), Point B (0.4. 0.25, 0.35), Point C (0.52, 0.01, 0.47), Point D (0.9, 0.005, 0.095), and Point B (0.9, 0.09, 0.01) or on the lines connection the Points, and at least one of (a) at least one oxide selected from the group consisting of aluminum oxide and titanium oxide in an amount of 50% or less by weight of the total amount, (b) a mixed oxide ceramic material including at least one crystal phase selected from the group consisting of ReBO 3 , Re 3 BO 6 , Re(B 2 O 3 ) 3 and ReB 3 O 6 , (c) a crystallization glass that can precipitate at least one crystal phase selected from the group consisting of ReBO 3 , Re 3 BO 6 , Re(B 2 O 3 ) 2 and ReB 3 O 6 and (d) a crystallization glass that can precipitate at least one crystal phase selected from the group consisting of ReBO 3 , Re 3 BO 6 , Re(B 2 O 3 ) 2 and ReB 3 O 6 .

15. The ceramic substrate composition according to claim 14 , wherein the mixed oxide ceramic material is 20% to 90% by weight of the total amount of the glass and the mixed oxide ceramic material, is calcined dB 2 O 3 -eRe 2 O 3 in which the molar ratio d/e=1/3 to 3/1 and optionally further contains ZnO; and wherein the crystallization glass is 20% to 90% by weight of the total amount of the glass and the crystallization glass and is represented by gB 2 O 3 -hRe 2 O 3 -iZnO in which g+h+i=1 and the molar amounts g, h, and i fall within a region defined in a ternary composition diagram by Point F (0.4, 0.595, 0.005), Point G (0.4, 0.25, 0.35), Point H (0.52, 0.01, 0.47), Point I (0.9, 0.005, 0.095), and Point J (0.9, 0.09, 0.01) or on the lines connected those Points; and wherein the total molar amounts of B 2 O 3 , Re 2 O 3 and ZnO in the composition are such that they fall within a region defined in a ternary composition diagram by Points A through E or on the lines connected those Points.