Wiring board providing impedance matching

• US 7,339,260 B2
• Filed: 08/27/2004
• Issued: 03/04/2008
• Est. Priority Date: 08/27/2004
• Status: Expired due to Fees

• Current Assignee: NGK Spark PLUG Company Limited
• Original Assignee: NGK Spark PLUG Company Limited
• Inventors: Suzuki, Kazuhiro, Higo, Kazunaga, Sugimoto, Yasuhiro
• Primary Examiner(s): WILLIAMS, ALEXANDER O
• Application Number:
  US10/927,134
• Publication Number:
  US 20060043572A1
• Time in Patent Office: 1,285 Days
• Field of Search: 257/E23.063, 257/E23.067, 257/E23.079, 257/E23.07, 257/E23.062, 257/700, 257/698, 257/774, 257/678, 257/668, 361/316, 361/760, 361/761, 174/260
• US Class Current: 257/668
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H05K 1/0222 for shielding around a single via or around a group of vias, e.g. coaxial vias or vias surrounded by a grounded via fence
• CPC Class Codes: H05K 1/0251 related to vias or transitions between vias and transmission lines
• CPC Class Codes: H05K 1/113 Via provided in pad; Pad over filled via
• CPC Class Codes: H05K 2201/093 Layout of power planes, ground planes or power supply conductors, e.g. having special clearance holes therein reduction of cross-talk, noise or interference by patterned shielding planes, ground planes or power planes H05K1/0224
• CPC Class Codes: H05K 2201/09309 Core having two or more power planes; Capacitive laminate of two power planes
• CPC Class Codes: H05K 2201/09536 Buried plated through-holes, i.e. plated through-holes formed in a core before lamination
• CPC Class Codes: H05K 2201/096 Vertically aligned vias, holes or stacked vias
• CPC Class Codes: H05K 2201/09618 Via fence, i.e. one-dimensional array of vias
• CPC Class Codes: H05K 2201/09627 Special connections between adjacent vias, not for grounding vias redundant conductors or connections H05K2201/0979
• CPC Class Codes: H05K 2201/0969 Apertured conductors
• CPC Class Codes: H05K 2201/09718 Clearance holes
• CPC Class Codes: H05K 2201/09809 Coaxial layout reduction of cross-talk, noise or interference by printed shielding conductors for shielding around a single via or around a group of vias H05K1/0222
• CPC Class Codes: H05K 3/4602 characterized by a special circuit board as base or central core whereon additional circuit layers are built or additional circuit boards are laminated

Abstract

A wiring board comprising: a plate core having a first main surface and a second main surface; conductor layers including a conductor line; dielectric layers laminated alternately with said conductor layers on at least one of said first and second main surfaces; via conductors as defined herein; a signal through-hole as defined herein; a signal through-hole conductor as defined herein; a first path end pad as defined herein; a second path end pad as defined herein; a shield through-hole as defined herein; and a shield through-hole conductor as defined herein; wherein: a signal transmission path is formed as defined herein; at least one of said conductor layers is disposed on each of said first and second main surface sides; said surface conductor on said first main surface side and said conductor line form a strip line, a microstrip line, or a coplanar waveguide with constant characteristic impedance Z0; an inner surface of said shield through-hole is covered with said shield through-hole conductor; and an interaxis distance between said signal through-hole conductor and said shield through-hole conductor is adjusted as defined herein.

Claims

1. A wiring board comprising:

a plate core having a first main surface and a second main surface;

conductor layers including a conductor line;

dielectric layers laminated alternately with said conductor layers on at least one of said first and second main surfaces of said plate core;

via conductors formed to penetrate said dielectric layers;

a signal through-hole made to penetrate said plate core in a plate thickness direction;

a signal through-hole conductor with which an inner surface of said signal through-hole is covered;

a first path end pad provided on a first main surface side of said plate core;

a second path end pad formed on a second main surface side of said plate core;

a shield through-hole formed to penetrate said plate core in said plate thickness direction and located in a position adjacent to said signal through-hole in said plate core; and

a shield through-hole conductor connected to at least one of a surface conductor on said first main surface side and a surface conductor on said second main surface side in said plate core;

wherein;

a signal transmission path is formed to range from said first path end pad to said second path end pad and to include said conductor line, said via conductors, and said signal through-hole conductor;

at least one of said conductor layers is disposed on each of said first and second main surface sides of said plate core so as to form said surface conductor serving as a power supply layer or a ground layer;

said surface conductor on said first main surface side and said conductor line form a strip line, a microstrip line, or a coplanar waveguide with constant characteristic impedance ZO;

an inner surface of said shield through-hole is covered with said shield through-hole conductor in order to shield a high-frequency signal transmitted through said signal through-hole conductor;

an interaxis distance between said signal through-hole conductor and said shield through-hole conductor is adjusted so that characteristic impedance ZO′

of a shield transmission path structure formed by said signal through-hole conductor and said shield through-hole conductor is in a range of ZO±

20 Ω

; and

a fourth conductor layer including a third surface conductor, a third dielectric layer, a fifth conductor layer including a fourth surface conductor, and a fourth dielectric layer are laminated successively on said second main surface of said plate core in order of increasing distance from said plate core;

a through-hole opening is formed in said fourth conductor layer and in a position of said third surface conductor corresponding to said signal through-hole conductor, and a through-hole pad electrically connected to said signal through-hole conductor is disposed in an inside of said through-hole opening so as to form an annular gap between said through-hole pad and said through-hole opening;

a via opening is formed in said fifth conductor layer and in a position of said fourth surface conductor corresponding to said signal through-hole conductor, and third signal via conductors formed to penetrate said third dielectric layer and said fourth dielectric layer while connected to said through-hole pad are disposed in an inside of said via opening; and

said third surface conductor and said fourth surface conductor form ground conductors or power supply conductors, and a shield via conductor for shielding a high-frequency signal transmitted through said third signal via conductors is provided in said third dielectric layer so as to be connected to at least one of said third surface conductor and said fourth surface conductor.

3. The wiring board according to claim 1, wherein a plurality of said shield through-hole conductors are disposed around said signal through-hole conductor.

5. The wiring board according to claim 1, wherein impedance adjustment openings for adjusting characteristic impedance of said signal transmission path are formed in said surface conductors in positions facing said signal transmission path through said dielectric layers.

7. The wiring board according to claim 5, wherein;

a first conductor layer including a first surface conductor, a first dielectric layer, a second conductor layer including a conductor line, and a second dielectric layer are laminated successively on said first main surface of said plate core in order of increasing distance from said plate core;

said signal through-hole is formed to penetrate said plate core in said plate thickness direction and in a position opposite to a first end portion of said conductor line, and a first main surface side end portion of said signal through-hole conductor with which said inner surface of said signal through-hole is covered is connected to said first end portion of said conductor line through a first signal via conductor formed to penetrate said first dielectric layer, while said second path end pad connected to a second main surface side end portion of said signal through-hole conductor is disposed on said second main surface side of said plate core;

a second signal via conductor formed to penetrate said second dielectric layer is connected to a second end portion of said conductor line, and said first path end pad electrically connected to said second signal via conductor is disposed on said second dielectric layer; and

a first impedance adjustment opening for adjusting characteristic impedance of said signal transmission path from said first path end pad to said second path end pad is formed in said first surface conductor and in a position opposite to said second end portion of said conductor line.

9. The wiring board according to claim 7, wherein an inner diameter d1 of said first impedance adjustment opening is set to be in a range of d1≦

d2 in which said inner diameter of said first impedance adjustment opening is d1 and an outer diameter of said first path end pad is d2.

11. The wiring board according to claim 5, wherein:

said first conductor layer, said first dielectric layer, said second conductor layer, said second dielectric layer, and a third conductor layer including a second surface conductor are laminated successively on said first main surface of said plate core in order of increasing distance from said plate core;

said conductor line is interposed between said first surface conductor and said second surface conductor so as to form a strip line;

a first path end pad opening is formed in said second surface conductor so as to surround said second signal via conductor, and said first path end pad electrically connected to said second signal via conductor is disposed in an inside of said first path end pad opening so as to form an annular gap between said first path end pad and said first path end pad opening; and

a second impedance adjustment opening for adjusting characteristic impedance of said signal transmission path is provided in a position opposite to said first end portion of said conductor line in said second surface conductor.

13. The wiring board according to claims 5, wherein:

a fourth conductor layer including a third surface conductor, a third dielectric layer, a fifth conductor layer including a fourth surface conductor, a fourth dielectric layer and a sixth conductor layer including a fifth surface conductor are laminated successively on said second main surface of said plate core in order of increasing distance from said plate core;

a through-hole opening is formed in said fourth conductor layer and in a position of said third surface conductor corresponding to said signal through-hole conductor, and a through-hole pad electrically connected to said signal through-hole conductor is disposed in an inside of said through-hole opening so as to form an annular gap between said through-hole pad and said through-hole opening;

a via opening is formed in said fifth conductor layer and in a position of said fourth surface conductor corresponding to said signal through-hole conductor, and third signal via conductors formed to penetrate said third dielectric layer and said fourth dielectric layer while connected to said through-hole pad are disposed in an inside of said via opening;

a second path end pad opening is formed in said sixth conductor layer and in a position of said fifth surface conductor corresponding to said signal through-hole conductor, and said second path end pad electrically connected to said third signal via conductors is disposed in an inside of said second path end pad opening so as to form an annular gap between said second path end pad and said second path end pad opening; and

said through-hole pad, said via opening, said second path end pad and said second path end pad opening are all disposed concentrically, and an inner diameter d4 of said via opening is adjusted to be in a range of d3≦

d4≦

d5 in which d3 is an outer diameter of said through-hole pad, d4 is said inner diameter of bald via opening, d5 is an inner diameter of said second path end pad opening, so that said via opening serves as an impedance adjustment hole.

15. The wiring board according to claim 13, wherein said inner diameter d4 of said via opening is adjusted to be in a range of d3≦

d4≦

d6 in which d6 is an outer diameter of said second path end pad.

17. The wiring board according to claim 5, wherein said impedance adjustment openings are provided as a combination of a plurality of kinds of openings different in terms of at least one of shape of a signal transmission path side conductor portion of each opening forming parasitic capacitance with a surface conductor portion around said opening, size of said signal transmission path side conductor portion, and relative position relation between said surface conductor portion and said signal transmission path side conductor portion.

2. A wiring board comprising:

a plate core having a first main surface and a second main surface;

conductor layers including a conductor line;

dielectric layers laminated alternately with said conductor layers on at least one of said first and second main surfaces of said plate core;

via conductors formed to penetrate said dielectric layers;

a signal through-hole made to penetrate said plate core in a plate thickness direction;

a signal through-hole conductor with which an inner surface of said signal through-hole is covered;

a first path end pad provided on a first main surface side of said plate core;

a second path end pad formed on a second main surface side of said plate core;

a shield through-hole formed to penetrate said plate core in said plate thickness direction and located in a position adjacent to said signal through-hole in said plate core; and

a shield through-hole conductor connected to at least one of said surface conductor on said first main surface side and said surface conductor on said second main surface side in said plate core;

wherein;

a signal transmission path is formed to range from said first path end pad to said second path end pad and to include said conductor line, said via conductors, and said signal through-hole conductor;

at least one of said conductor layers is disposed on each of said first and second main surface sides of said plate core so as to form a surface conductor serving as a power supply layer or a ground layer;

said surface conductor on said first main surface side and said conductor line form a strip line, a microstrip line, or a coplanar waveguide with constant characteristic impedance ZO;

an inner surface of said shield through-hole is covered with said shield through-hole conductor in order to shield a high-frequency signal transmitted through said signal through-hole conductor;

an outer diameter of each of said signal through-hole conductor and said shield through-hole conductor is adjusted so that characteristic impedance ZO′

of a shield transmission path structure formed by said signal through-hole conductor and said shield through-hole conductor is in a range of ZO±

20 Ω

; and

a fourth conductor layer including a third surface conductor, a third dielectric layer, a fifth conductor layer including a fourth surface conductor, and a fourth dielectric layer are laminated successively on said second main surface of said plate core in order of increasing distance from said plate core;

a through-hole opening is formed in said fourth conductor layer and in a position of said third surface conductor corresponding to said signal through-hole conductor, and a through-hole pad electrically connected to said signal through-hole conductor is disposed in an inside of said through-hole opening so as to form an annular gap between said through-hole pad and said through-hole opening;

a via opening is formed in said fifth conductor layer and in a position of said fourth surface;

conductor corresponding to said signal through-hole conductor, and third signal via conductors formed to penetrate said third dielectric layer and said fourth dielectric layer while connected to said through-hole pad are disposed in an inside of said via opening; and

said third surface conductor and said fourth surface conductor form ground conductors or power supply conductors, and a shield via conductor for shielding a high-frequency signal transmitted through said third signal via conductors is provided in said third dielectric layer so as to be connected to at least one of said third surface conductor and said fourth surface conductor.

4. The wiring board according to claim 2, wherein a plurality of shield through-hole conductors similar to and in place of said shield through-hole conductor are disposed around said signal through-hole conductor.

6. The wiring board according to claim 2, wherein impedance adjustment openings for adjusting characteristic impedance of said signal transmission path are formed in said surface conductors in positions facing said signal transmission path through said dielectric layers.

8. The wiring board according to claim 6, wherein:

a first conductor, layer including a first surface conductor, a first dielectric layer, a second conductor layer including a conductor line, and a second dielectric layer are laminated successively on said first main surface of said plate core in order of increasing distance from said plate core;

said signal through-hole is formed to penetrate said plate core in said plate thickness direction and in a position opposite to a first end portion of said conductor line, and a first main surface side end portion of said signal through-hole conductor with which said inner surface of said signal through-hole is covered is connected to said first end portion of said conductor line through a first signal via conductor formed to penetrate said first dielectric layer, while said second path end pad connected to a second main surface side end portion of said signal through-hole conductor is disposed on said second main surface side of said plate core;

a second signal via conductor formed to penetrate said second dielectric layer is connected to a second end portion of said conductor line, and said first path end pad electrically connected to said second signal via conductor is disposed on said second dielectric layer; and

a first impedance adjustment opening for adjusting characteristic impedance of said signal transmission path from said first path end pad to said second path end pad is formed in said first surface conductor and in a position opposite to said second end portion of said conductor line.

10. The wiring board according to claim 8, wherein an inner diameter d1 of said first impedance adjustment opening is set to be in a range of d1≦

d2 in which said inner diameter of said first impedance adjustment opening is d1 and an outer diameter of said first path end pad is d2.

12. The wiring board according to claim 6, wherein:

said first conductor layer, said first dielectric layer, said second conductor layer, said second dielectric layer, and a third conductor layer including a second surface conductor are laminated successively on said first main surface of said plate core in order of increasing distance from said plate core;

said conductor line is interposed between said first surface conductor and said second surface conductor so as to form a strip line;

a first path end pad opening is formed in said second surface conductor so as to surround said second signal via conductor, and said first path end pad electrically connected to said second signal via conductor is disposed in an inside of said first path end pad opening so as to form an annular gap between said first path end pad and said first path end pad opening; and

a second impedance adjustment opening for adjusting characteristic impedance of said signal transmission path is provided in a position opposite to said first end portion of said conductor line in said second surface conductor.

14. The wiring board according to claims 6, wherein:

a fourth conductor layer including a third surface conductor, a third dielectric layer, a fifth conductor layer including a fourth surface conductor, a fourth dielectric layer and a sixth conductor layer including a fifth surface conductor are laminated successively on said second main surface of said plate core in order of increasing distance from said plate core;

a through-hole opening is formed in said fourth conductor layer and in a position of said third surface conductor corresponding to said signal through-hole conductor, and a through-hole pad electrically connected to said signal through-hole conductor is disposed in an inside of said through-hole opening so as to form an annular gap between said through-hole pad and said through-hole opening;

a via opening is formed in said fifth conductor layer and in a position of said fourth surface conductor corresponding to said signal through-hole conductor, and third signal via conductors formed to penetrate said third dielectric layer and said fourth dielectric layer while connected to said through-hole pad are disposed in an inside of said via opening;

a second path end pad opening is formed in said sixth conductor layer and in a position of said fifth surface conductor corresponding to said signal through-hole conductor, and '"'"'said second path end pad electrically connected to said third signal via conductors is disposed in an inside of said second path end pad opening so as to form an annular gap between said second path end pad and said second path end pad opening; and

said through-hole pad, said via opening, said second path end pad and said second path end pad opening are all disposed concentrically, and an inner diameter d4 of said via opening is adjusted to be in a range of d3≦

d4≦

d5 in which d3 is an outer diameter of said through-hole pad, d4 is said inner diameter of said via opening, d5 is an inner diameter of said second path end pad opening, so that said via opening serves as an impedance adjustment hole.

16. The wiring board according to claim 14, wherein said inner diameter d4 of said via opening is adjusted to be in a range of d3≦

d4≦

d6 in which d6 is an outer diameter of said second path end pad.

18. The wiring board according to claim 6, wherein said impedance adjustment openings are provided as a combination of a plurality of kinds of openings different in terms of at least one of shape of a signal transmission path side conductor portion of each opening forming parasitic capacitance with a surface conductor portion around said opening, size of said signal transmission path side conductor portion, and relative position relation between said surface conductor portion and said signal transmission path side conductor portion.