How to make a multilayer circuit board

Abstract

A method for manufacturing a multilayer circuit board, comprising the following steps: providing an inner circuit substrate, the inner circuit substrate at least including a base material layer and a first conductive circuit layer formed on a surface of the base material layer; The first conductive circuit layer includes a plurality of first conductive circuits; a first cover film is formed on the first conductive circuit layer, and the first cover film includes a first opening, and a part of the first conductive circuit from the first exposed in the opening; an outer line seed layer is formed on the first cover film, and an inner line protection layer is formed on the first conductive line exposed from the first opening, and the inner line protection layer The layer is non-copper metal or resist; forming a third conductive circuit layer on the outer circuit seed layer; and removing the outer circuit seed layer and the inner circuit protection layer. The manufacturing method of the multi-layer circuit board provided by the invention can reduce work flow and improve circuit reliability.

Description

technical field [0001] The invention relates to a printed circuit board technology, in particular to a method for manufacturing a multilayer circuit board. Background technique [0002] The multilayer circuit board includes an inner layer circuit substrate and an outer layer circuit. In the prior art, the manufacturing method of the outer layer circuit board is as follows: the outer layer single-sided board and the pure glue of the connection layer are respectively opened and then pressed with the inner layer circuit substrate, and then the outer layer circuit is manufactured through an image transfer process. Among them, it is necessary to use dry film or peelable adhesive to protect the inner circuit and resolve the outer circuit. [0003] However, the manufacturing method of this multilayer circuit board has the following disadvantages: 1. The combination of the outer layer and the inner layer is formed by pressing the single and double panels with pure glue, and the sin...

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Problems solved by technology

[0003] However, the manufacturing method of this multilayer circuit board has the following disadvantages: 1. The combination of the outer layer and the inner layer is formed by pressing the single and double panels with pure glue, and the single panel and the pure glue need to be opened separately

If you make a multi-layer board with more than three layers, the assembly process will be multiplied

2. When making the outer circuit, when using dry film to protect the inner layer and analyze the outer circuit, it often occurs that the circuit at the inner layer is etched or the outer circuit is poorly resolved, which makes the reliability of the circuit board poor.

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