Printed circuit board and method for producing a printed circuit board of this type and for producing a laminar composite material for such a printed circuit board

• US 20040028883A1
• Filed: 04/11/2003
• Published: 02/12/2004
• Est. Priority Date: 10/13/2000
• Status: Active Grant

• Current Assignee: PPC Electronic AG
• Original Assignee: PPC Electronic AG
• Inventors: Weber, Peter, Straub, Peter
• Granted Patent: US 7,226,653 B2
• Time in Patent Office: Days
• US Class Current: 428/209
• CPC Class Codes: H05K 1/0306 Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A printed circuit board for an electronic circuit, especially for the ultra-high frequencies located in the GHz range that comprises at least one conductor layer, which is arranged on top of an insulating layer and which is flatly joined to said insulating layer. Improved mechanical, thermal and electrical properties are attained by virtue of the fact that the insulating layer is a thin glass layer.

Claims

1. A printed circuit board (10, 20, 30) for an electronic circuit, in particular for extremely high frequencies in the GHz range, comprising at least one conductor layer (11, 15;

23, 24;

31, 34, 35, 38), which is arranged on an insulating layer and which is connected to the insulating layer in planar fashion, characterized in that the insulating layer is a thin glass layer (13, 13′

, 13″

).

2. The printed circuit board as claimed in claim 1, characterized in that a respective conductor layer (11, 15;

23, 24;

31, 34, 35, 38) is arranged on both sides of the thin glass layer (13, 13′

, 13″

) and connected to the thin glass layer (13, 13′

, 13″

) in planar fashion.

3. The printed circuit board as claimed in either of claims 1 and 2, characterized in that the thin glass layer (13, 13′

, 13″

) is pulled from the melt and comprises a modified borosilicate glass.

4. The printed circuit board as claimed in one of claims 1 to 3, characterized in that the thin glass layer (13, 13′

, 13″

) has a thickness in the range from a few μ

m to a few mm, preferably in the range between 30 μ

m and 1.1 mm.

5. The printed circuit board as claimed in one of claims 1 to 4, characterized in that the thin glass layer (13, 13′

, 13″

) has, at 1 MHz, a relative permittivity ε

_r of between 6 and 7, preferably of about 6.2, and a dielectric loss factor tanδ

of about 9×

10<sup>−

4</sup>.

6. The printed circuit board as claimed in one of claims 1 to 5, characterized in that the thin glass layer (13, 13′

, 13″

) has, for temperatures of between 20 and 300°

C., a thermal expansion coefficient α

_20-300 of between 4×

10<sup>−

6</sup>K<sup>−

1</sup> and 8×

10<sup>−

6</sup>K<sup>−

1</sup>, preferably of about 4.5×

10<sup>−

6</sup>K<sup>−

1</sup>.

7. The printed circuit board as claimed in one of claims 1 to 6, characterized in that the conductor layers (11, 15;

23, 24;

31, 34, 35, 38) in each case comprise a metal foil, preferably a Cu metal foil.

8. The printed circuit board as claimed in claim 7, characterized in that the metal foils have a thickness of between 5 and 50 μ

m, preferably of 18 or 35 μ

m.

9. The printed circuit board as claimed in either of claims 7 and 8, characterized in that the metal foils are adhesively bonded to the thin glass layers (13, 13′

, 13″

) in each case by means of a connecting layer (12, 14;

22, 25;

32, 33, 36, 37;

39, 40).

10. The printed circuit board as claimed in claim 9, characterized in that the connecting layers (12, 14;

22, 25;

32, 33, 36, 37;

39, 40) essentially comprise a resin.

11. The printed circuit board as claimed in claim 10, characterized in that the connecting layers (12, 14;

22, 25;

32, 33, 36, 37;

39, 40) are additionally provided with a silane as adhesion promoter.

12. The printed circuit board as claimed in one of claims 9 to 11, characterized in that the connecting layers (12, 14;

22, 25;

32, 33, 36, 37;

39, 40) each have a thickness of a few 0.10 μ

m, preferably about 20 μ

m, between the conductor layers (11, 15;

23, 24;

31, 34, 35, 38) and the adjacent thin glass layers (13, 13′

, 13″

).

13. The printed circuit board as claimed in one of claims 9 to 12, characterized in that the surfaces of the thin glass layers (13, 13′

, 13″

) are pretreated in order to improve the adhesion.

14. The printed circuit board as claimed in one of claims 1 to 13, characterized in that the printed circuit board (10) comprises an individual thin glass layer (13) which is adhesively bonded to metal foils on both sides.

15. The printed circuit board as claimed in one of claims 1 to 13, characterized in that the printed circuit board (20) comprises, in a stack one above the other, a plurality of thin glass layers (13, 13′

, 13″

) adhesively bonded to metal foils.

16. The printed circuit board as claimed in one of claims 1 to 13, characterized in that the printed circuit board (20) comprises, besides a thin glass layer (13), at least one further insulating plate (21, 26) made of a different insulating material.

17. A method for producing a layer composite material, in particular for a printed circuit board as claimed in one of claims 1 to 15, characterized in that a thin glass layer (13) is provided with a conductor layer (11, 15;

23, 24;

31, 34, 35, 38) by being adhesively bonded at least on one side, in planar fashion, to a resin-coated metal foil (28, 29), in particular a resin-coated Cu metal foil.

18. The method as claimed in claim 17, characterized in that the thin glass layer (13) is adhesively bonded to a resin-coated metal foil (28, 29), in particular a resin-coated Cu metal foil, on both sides.

19. The method as claimed in either of claims 17 and 18, characterized in that the layer composite formed is adhesively bonded to further thin glass layers (13′

, 13″

) and resin-coated metal foils.

20. The method as claimed in one of claims 17 to 19, characterized in that a thin glass layer (13) is used which

(a) is pulled from the melt and comprises a modified borosilicate glass,

(b) has a thickness in the range from a few μ

m to a few mm, preferably in the range between 30 μ

m and 1.1 mm,

(c) has, at 1 MHz, a relative permittivity ε

_r of between 6 and 7, preferably of about 6.2, and a dielectric loss factor tanδ

of about 9×

10<sup>−

4</sup> and

(d) has, for temperatures of between 20 and 300°

C., a thermal expansion coefficient α

_20-300 of between 4×

10<sup>−

6</sup>K<sup>−

1</sup> and 8×

10<sup>−

6</sup>K<sup>−

1</sup>, preferably of about 4.5×

10⁶K<sup>−

1</sup>.

21. The method as claimed in one of claims 17 to 20, characterized in that the resin-coated metal foils has a metal foil thickness of between 5 and 50 μ

m, preferably of 18 or 35 μ

m.

22. The method as claimed in one of claims 17 to 21, characterized in that the surfaces of the thin glass layer (13) are pretreated in order to improve the adhesion.

23. A method for producing a printed circuit board as claimed in one of claims 1 to 16, characterized in that, in order to form a layer composite integrated into the printed circuit board (20), a thin glass layer (13) is adhesively bonded to an insulating plate (21, 26) at least on one side, in planar fashion, which insulating plate is provided with a conductor layer (23, 24) on the adhesive-bonding side.