Multilayer circuit board and method for fabricating same

Abstract

The invention provides a multi-layer circuit board which can subtly install the circuit with a high density and a method for producing the multi-layer circuit board stably and cheaply. The multi-layercircuit board and its producing method are characterized in that: laying the outer reinforced layer on the inner core plate and connecting by connecting holes between layers; the conductor thicknessof the bearing platform forming the connecting holes between layers on the inner core plate is more than the inner core plate wiring pattern except for connecting holes between layers.

Description

technical field [0001] The invention relates to an enhanced multilayer circuit board and a manufacturing method thereof, in particular to a multilayer circuit board with a thinned wiring pattern of an enhanced layer and a manufacturing method thereof. Background technique [0002] In recent years, the miniaturization and high performance of electronic devices have been increasing, and therefore, the demand for higher density of circuit boards has increased. [0003] Therefore, in order to achieve high-density installation, double-sided or multilayer flexible circuit boards are used as core boards, and reinforced multilayer flexible circuit boards with 1 to 2 layers of reinforcement layers on both sides or one side have also been put into practical use (patent Literature 1). [0004] However, there is a problem that it is not necessarily easy to carry out high-density mounting on the above-mentioned enhanced multilayer flexible circuit board. That is to say, when the circui...

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Problems solved by technology

[0016] As mentioned above, if electrolytic plating of about 25 to 30 μm is performed on a 12 μm thick copper foil, the thickness becomes 37 to 42 μm, and it is difficult to form a fine pattern with a circuit pitch of 100 μm with a good yield, so high-density packaging cannot be satisfied. requirements

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