Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2001-03-16
2004-04-06
Vigushin, John B. (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S261000, C174S264000, C361S734000, C257S698000
Reexamination Certificate
active
06717071
ABSTRACT:
This application incorporates by reference Taiwanese application Serial No. 089116185, Filed Aug. 11, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to a structure of a coaxial via hole, and more particularly to a coaxial via hole, which can be applied as a capacitor or a resistor and has the function of signal shielding.
2. Description of the Related Art
The development and progress of the IC (Integrated Circuit) integration and fabrication and the advance of device package and circuit design is always aimed to be smaller and lighter.
Conventionally, capacitor is fixed on the circuit board by Surface Mounted Technique (SMT), as shown in FIG.
1
. The capacitor
102
is fixed on the pad
104
and the pad
104
is fixed on the circuit board (not shown). Trace
106
connects the pad
104
and via
108
on the circuit board. However, capacitor
102
fixed by SMT occupies large surface area, which is against the aim of size shrinking.
Via capacitors within substrate is proposed, with the development of high dielectric constant material. A typical one is disclosed in a U.S. Pat. No. 5,055,966.
FIG. 2A
shows the structure of the via capacitor within the multi-layer substrate;
FIG. 2B
is the cross-sectional view of the structure in
FIG. 2A
;
FIG. 2C
is the equivalent circuit of the capacitor at multi-layer substrate. The circuit board contains substrates L
1
, L
2
, L
3
, L
4
and L
5
. A via
203
is formed in the substrate L
3
and the via
203
is filled with dielectric. The conductive trace
204
above the via
203
, the conductive trace
206
below the via
203
and the via
203
itself together form a capacitor. The capacitance C thereof is a function of the thickness of the substrate L
3
, the diameter of the via
203
and the dielectric constant of the dielectric.
Referring to
FIGS. 3A
to
3
C, another structure of the conventional inter-layer capacitor is disclosed in U.S. Pat. No. 5,972,231, which contains two conductive plates
302
,
304
of polygonal shape on top and bottom of the substrate
306
. The conductive plates
302
,
304
are coupled to surrounding circuitry at the polygonal vertices through conductive traces
308
,
310
, respectively. The inter-layer capacitor can be further extended to be a capacitor between multi-layer substrates by using via holes.
The two conventional capacitors mentioned-above occupy smaller horizontal surface but more substrate layers. However, increasing number of substrate layer is not acceptable for some Printed Circuit Boards (PCBs) with high device density. Similar problems also occur in the resistor structure.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a coaxial via hole used in a carrier, includes an outer cylinder-shaped conductor, an inner cylinder-shaped conductor, and an insulating fill. The outer cylinder-shaped conductor extends along the first direction. The inner cylinder-shaped conductor is in the outer cylinder-shaped conductor and extends along the first direction. The insulating fill is between the outer cylinder-shaped conductor and the inner cylinder-shaped conductor. It is therefore another object of the invention to provide a method of manufacturing a coaxial via hole. First, the first hole is formed in a carrier. A process to make the first hole become conduct electricity is then performed to form an outer cylinder-shaped conductor on the interior of the first hole. Next, an insulating material is placed in the outer cylinder-shaped conductor to form an insulating fill. The second hole in the insulating fill is then formed. The second hole has a diameter smaller than the diameter of the first hole. Next, a process to make the second hole become conduct electricity is performed to form an inner cylinder-shaped conductor on the interior of the second hole.
It is therefore another object of the invention to provide a coaxial via hole used in a carrier. The coaxial via hole includes an outer cylinder-shaped conductor, an inner cylinder-shaped conductor and an electrical-resistant fill. The outer cylinder-shaped conductor extends along the first direction. The inner cylinder-shaped conductor is in the outer cylinder-shaped conductor and extends along the first direction. The electrical-resistant fill is between the outer cylinder-shaped conductor and the inner cylinder-shaped conductor.
It is therefore a further object of the invention to provide a method of manufacturing a coaxial via hole. First, the first hole is formed in a PCB. A process to set hole become conduct electricity is then performed to form an outer cylinder-shaped conductor on the interior of the first hole. Next, an electrical-resistant material is placed in the outer cylinder-shaped conductor to form an electrical-resistant fill. The second hole in the electrical-resistant fill is then formed. The second hole has a diameter smaller than the diameter of the first hole. Next, a process to set hole become conduct electricity is performed to form an inner cylinder-shaped conductor on the interior of the second hole.
REFERENCES:
patent: 4211603 (1980-07-01), Reed
patent: 4675788 (1987-06-01), Breitling et al.
patent: 5072075 (1991-12-01), Lee et al.
patent: 5257452 (1993-11-01), Imai et al.
patent: 5374788 (1994-12-01), Endoh et al.
patent: 5689091 (1997-11-01), Hamzehdoost et al.
patent: 5834705 (1998-11-01), Jonaidi
patent: 5949030 (1999-09-01), Fasano et al.
patent: 6353999 (2002-03-01), Cheng
Chang Huey-Ru
Ho Ted C.
Lee Min-Lin
Alcala José H.
Industrial Technology Research Institute
Rabin & Berdo PC
Vigushin John B.
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