Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
1999-06-11
2001-12-04
Gaffin, Jeffrey (Department: 2841)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S261000, C361S792000, C361S794000
Reexamination Certificate
active
06326556
ABSTRACT:
TECHNICAL FIELD
This invention relates to a multilayer printed wiring board, and more particularly it proposes a multilayer printed wiring board characterized by having a conductor pattern of a power layer arranged for supplying a current to a signal layer.
BACKGROUND ART
In a multilayer printed wiring board formed by laminating interlaminar insulating layers and conductor layers, the conductor layers are divided into a power layer, a signal layer and a shield layer in accordance with use purpose and functioned individually. Among them, the power layer is usual to be a flat conductor pattern having a large surface area.
On the other hand, the multilayer printed wiring board is produced through an additive process by alternately building up a resin insulating layer and a conductor layer on a substrate and then electrically connecting the conductor layers to each other through a viahole formed in the resin insulating layer. In the production process of such a multilayer printed wiring board, therefore, there is a tendency that a solvent is liable to be retained in the interlaminar insulating layer disposed on a lower side of the conductor layer.
For example, when an air permeable resin layer such as a resist is formed on the interlaminar insulating layer, such a residual solvent is evaporated and removed by a heat treatment such as a drying treatment conducted at a plating step or the like, so that such a solvent does not particularly cause a problem.
However, when an impermeable metal layer such as a conductor layer is formed on the interlaminar insulating layer, it is very difficult to remove the above residual solvent by evaporation. Particularly, when the power layer having a flat pattern as a conductor pattern among the conductor layers is formed on the resin insulating layer through additive process, the residual solvent is retained between the power layer and the resin insulating layer as a vapor and there is a problem easily causing so-called “swelling of conductor layer”.
Further, such a “swelling of conductor layer” degrades the adhesion property between the resin insulating layer and the conductor and hence causes the lowering of the interlaminar insulating property.
It is, therefore, an object of the invention to provide a multilayer printed wiring board capable of solving the above problems resulting from the residual solvent, and to particularly propose a conductor pattern of a power layer capable of preventing the swelling of the conductor layer and effectively acting to improve the adhesion property between the resin insulating layer and the conductor.
SUMMARY OF THE INVENTION
The inventors have made various studies in order to achieve the above object and as a result the present invention relates to a multilayer printed wiring board formed by laminating resin insulating layers and conductor layers on a substrate, wherein the surface of the resin insulating layer is roughened and among conductor layers at least constituted with signal layer and power layer, a conductor pattern of the power layer is of lattice-shaped form.
In the above multilayer printed wiring board, the power layer is desirable to have such a conductor pattern that a conductor width of the lattice-shaped conductor is 100 &mgr;m~5 mm and a distance between the conductor is 100 &mgr;m~10 mm.
Also, the conductor pattern of the power layer in the multilayer printed wiring board is desirable that each corner part in a cross portion of the lattice-shaped conductor is curved.
Moreover, the resin insulating layer constituting the multilayer printed wiring board according to the invention is desirable to be formed by dispersing heat-resistant resin particles soluble in an acid or an oxidizing agent into a heat-resistant resin (or a photosensitive resin) hardly soluble in an acid or an oxidizing agent. The surface of such a resin insulating agent is roughened by removing the heat-resistant resin particles with the acid or oxidizing agent. On the other hand, when the lattice-shaped power layer is formed, the plated resist is an isolated shape surrounded with the conductors and is liable to be peeled off as it is. In this point, when the plated resist is formed on the above roughened surface, the plated resist hardly peels off even in the isolated shape and hence the reliability is ensured.
In one aspect, the present invention is directed to a multilayer printed wiring board comprising a substrate; at least one resin insulating layer and at least one conductor layer laminated on the substrate; the at least one resin insulating layer comprising a roughened surface; the at least one conductor layer comprising at least a signal layer and a power layer; and the power layer comprising a lattice-shaped conductor pattern including a conductor width of about 100 &mgr;m to 5 mm, and a distance from a conductor edge to an opposing conductor edge of about 100 &mgr;m to 10 mm.
Each corner part in a cross portion of the lattice-shaped conductor pattern can be curved.
The at least one resin insulating layer and the at least one conductor layer can comprise a plurality of insulating layers and conductor layers.
REFERENCES:
patent: 5061547 (1991-10-01), Plesinger et al.
patent: 5519176 (1996-05-01), Goodman et al.
patent: 54113863 (1979-09-01), None
patent: 54149646 (1979-10-01), None
patent: 54150675 (1979-11-01), None
patent: 61106079 (1986-07-01), None
patent: 3-97973 (1991-10-01), None
patent: 7202359 (1995-08-01), None
patent: 7321463 (1995-12-01), None
patent: 9-8465 (1997-01-01), None
An English Language abstract of JP 61-106079.
An English Language abstract of JP 7-321463.
An English Language abstract of JP 7-202359.
An English Language abstract of JP 3-97973.
An English Language abstract of JP 54-150675.
An English Language abstract of JP 54-149646.
An English Language abstract of Jp 54-113863.
An English Language abstract of JP 9-8465.
Asai Motoo
Nakamura Akihito
Alcala José H.
Gaffin Jeffrey
Greenblum & Bernstein P.L.C.
Ibiden Co. Ltd.
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