Bump electrode and printed circuit board
AssigneeRicoh Microelectronics Co., Ltd.
InventorMakoto Kinoshita
Life of this patent
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Abstract
A bump electrode is a bump made from a fused metal in a shape of one of a circular cylinder, a cone, a pyramid, a frustum of a cone, and a frustum of a pyramid, formed on a substrate. A printed circuit board has a substrate and a wiring pattern provided thereon. The wiring pattern is made from one of a paste and a fused metal and has a cross-section at right angles with respect to an extending direction of the wiring pattern with such an aspect ratio of a depth thereof to a width thereof that the depth thereof is greater than a depth with an aspect ratio of 1:5 and the width thereof is smaller than a width with an aspect ratio of 1:5.
Claims3
A printed circuit board comprising:
- a printed circuit substrate;
- a first wiring pattern, made from a paste or a fused metal, and formed on a surface of a front side or a back side of said printed circuit substrate;
- and
- a second wiring pattern, made from a paste or a fused metal, and formed in contact with said surface and so as to cross said first wiring pattern, thereby forming at least one of a junction portion of said first wiring pattern and said second wiring pattern and a crossover portion of said first wiring pattern and said second wiring pattern with a resistive coating interposed between said first and second wiring patterns in said crossover portion, wherein
- at least one of said first wiring pattern and said second wiring pattern has a rectangular shaped cross-section with an aspect ratio of a thickness to a width of the cross-section being greater than 1:1,
- said first and second wiring patterns form a cross-over portion and said resistive coating is a localized thin film resistive coating interposed between said first wiring pattern and said second wiring pattern and confined only to said cross-over portion, and
- said resistive coating consists of an insulating material having a substantially uniform composition.
Dependencies are inferred from the claim text.