Multilayer wiring board
View Patent ↗Provided is a multilayer wiring board, wherein impedance matching can be achieved in a via connection section by means of a configuration, which has a simple structure, and which can be easily processed. In the multilayer wiring board including a ground layer ( 401 ) of a layer ( 1 ), and a signal line ( 102 ) of a layer ( 2 ), an elliptical through hole is formed in the ground layer ( 401 ), said through hole being at a position facing a part of the signal line ( 102 ). The elliptical through hole overlaps the signal line ( 102 ) by a length of lambda/36-lambda/2 in the long axis direction, Impedance of the signal line ( 102 ) can be adjusted by adjusting the size of the through hole.
1. A multilayer wiring board comprising:
a via that connects a plurality of inner layers; and
a ground layer that forms an outer layer distinct from the plurality of inner layers along a direction perpendicular to layer surfaces, the ground layer including a metal film formed to define a cut pattern where no metal film is present at a position facing the via, the cut pattern overlapping a first portion of the via while not overlapping a second portion of the via.
2. The multilayer wiring board according to claim 1 , wherein the cut pattern has any one of a circular shape, an elliptical shape, and a rectangular shape.
3. The multilayer wiring board according to claim 2 , wherein the cut pattern has any one of a letter-C- shape and an n-cut shape.
4. The multilayer wiring board according to claim 1 , wherein the ground layer includes a through hole having a length of λ/4 along a signal line connected to the via.
5. The multilayer wiring board according to claim 4 , wherein the through hole has any one of a rectangular shape, a protruding shape, and a taper shape.