Method for improving pad-off phenomenon of blind holes in multi-stage circuit board, and multi-stage circuit board

Abstract

The invention discloses a method for improving the pad-off phenomenon of blind holes in a multi-stage circuit board, and the multi-stage circuit board. The method comprises the following steps: drilling a plug hole in a core board, metalizing the plug hole, filling the plug hole with resin, and metalizing the surface of the resin after grinding the board with an abrasive belt; manufacturing an inner-layer circuit on the core board; pressing the core plate and a copper foil into a first daughter board; drilling a first blind hole and a first-order blind hole in the first daughter board, and subjecting the first blind hole and the first-order blind hole to filling and levelling-up; pressing the first sub-plate and another copper foil into a second sub-plate; drilling a second blind hole and a second-order blind hole in the second daughter board in a depth-controlled mode, and subjecting the second blind hole and the second-order blind hole to filling and levelling-up; pressing the second daughter board and another copper foil into a production board; drilling a third-order blind hole and a through hole in the production board in a depth-controlled mode, and subjecting the third-order blind hole and the through hole to metalization; and sequentially carrying out subsequent processes on the production board to obtain the multi-stage circuit board. According to the method, dielectric thickness between the blind hole layers can be reduced, so the thickness-diameter ratio of the blind holes is reduced, and the problem of poor open circuit caused by the pad-off phenomenon caused by overlarge dielectric thickness between the blind hole layers is solved.

Description

technical field [0001] The invention relates to the technical field of printed circuit board production, in particular to a method for improving blind hole pad removal of a multi-level circuit board and the multi-level circuit board. Background technique [0002] Three-stage laser HDI board, this product is mainly used in the security module of the digital keypad control box of the ATM machine. There are 2 pieces of PCBA in the keyboard control box, one of which is the keyboard touchpad, and the other is the safety control panel under the touchpad. The working principle of the safety control board is as follows: There are safety induction keys at both ends of the PCBA to connect with the ATM machine. When there is external damage / mechanical intrusion, the device senses and transmits the intrusion signal to the safety control core. The BGA starts the self-destruct mode and formats the memory. , ATM automatically shuts down and cannot be restarted. The purpose of this board b...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the above-mentioned existing technical defects, and provides a method for improving the blind holes of multi-level circuit boards. The hole connection composition, according to the manufacturing method of the laser blind hole, can reduce the interlayer thickness of the blind hole, so that the thickness-to-diameter ratio of the blind hole becomes smaller, which is beneficial to the copper plating of the blind hole, and improves the reliability of the blind hole. Solved the problem of poor opening of blind holes due to excessive interlayer thickness.

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