Method for molding via hole of printed circuit board

Abstract

The invention relates to a method for molding a via hole of a printed circuit board, which comprises the steps of: film attachment, in which the surfaces of upper and lower surface copper layers of an insulating dielectric layer drilled with the via hole are attached with photosensitive films, and the positions, which correspond to the via hole, on the photosensitive films are provided with film openings; hole-sealing electroplating, in which an orifice end, which is near a first surface, of the via hole is closed through a copper electroplating process on the first surface of the insulating dielectric layer; hole-filling electroplating, in which the via hole is completely filled with copper, and the filled copper is connected with the surface copper layer of a second surface of the insulating dielectric layer, namely the connection of solid via holes between upper and lower adjacent line layer patterns is realized; and the post-treatment, in which the two surfaces of the insulating dielectric layer are subjected to subsequent treatment respectively, and a level conducting surface which is convenient for implementing subsequent pattern line production working procedures is obtained by removing the photosensitive films, removing the filled copper higher than the surface copper layers, and leveling the board surface. The method has the advantages of simple, convenient and feasible process, low cost, and small area occupation, and upper and lower corresponding line rackets of the hole are integrally preserved, are not damaged by the via hole and have good electrical properties.

Description

technical field [0001] The invention relates to a technology for preparing printed circuit boards, in particular to a method for forming via holes in printed circuit boards. Background technique [0002] With the development of integrated circuits, the requirements for integrated circuit packaging have also increased, and the requirements for printed circuit boards used in packaging are also developing towards higher wiring density, better electrical performance and thermal performance. In order to meet the above requirements, the development of high-reliability via hole technology is the key, which has a great impact on the density of wiring and the electrical and thermal performance after packaging. [0003] As we all know, there must be several via holes on the printed circuit board to connect the circuits on the upper and lower adjacent conductive surfaces of the insulating medium layer. Such as figure 1 As shown, one of the traditional via hole manufacturing methods i...

AI Technical Summary

Problems solved by technology

However, these traditional copper vias will have a great negative impact on the subsequent process flow. For example, in the transfer process of the circuit pattern after the hollow copper vias are formed, the unevenness of the substrate surface caused by the hollow vias will cause photosensitive resistance. Poor adhesion of the etch film can easily cause line defects

In addition, this kind of through hole will have a great influence on the wiring design, so that the hole layout on the racket is limited, so that special wiring structures such as stacked holes cannot be realized, thus restricting the improvement of wiring density

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