Method for cleaning through hole smears of rigid-flexible printed circuit board

A printed circuit board, rigid-flex technology, applied in the secondary processing of printed circuits, cleaning/polishing of conductive patterns, chemical instruments and methods, etc. and other problems, to achieve the effect of good bite force, simple method and high decontamination efficiency

Inactive Publication Date: 2012-05-02
UNIV OF ELECTRONIC SCI & TECH OF CHINA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the investment in plasma cleaning equipment is large, and the investment of each equipment is more than 1 million, and the cleaning efficiency is low due to the influence of the v

Method used

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  • Method for cleaning through hole smears of rigid-flexible printed circuit board
  • Method for cleaning through hole smears of rigid-flexible printed circuit board
  • Method for cleaning through hole smears of rigid-flexible printed circuit board

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Use a mechanical numerical control machine to drill 0.25mm through holes in the four-layer rigid-flex printed circuit board. The structure of the rigid-flex board is a double-sided flexible board in the middle, and a single-sided rigid board on both sides. The rigid board is Shengyi 18 / 0.2FR-4 single-sided copper-clad laminate, and the flexible board is Taihong 18 / 25 / 18 calendered PI halogen-free double-sided copper-clad laminate. Use the method of the present invention to remove drilling dirt, then hole metallization, its technological process is as follows:

[0026] Step 1: Prepare two kinds of decontamination solutions;

[0027] Among them, the first decontamination solution contains 35g of sodium hydroxide or potassium hydroxide per liter, 30g of ethylene glycol ethyl ether used as an epoxy resin swelling agent, 2g of butanediol as a solubilizer, and 2g of butanediol as a polyimide swelling agent. 40ml of hydrazine, the rest is water; the second decontamination sol...

Embodiment 2

[0036] Use a mechanical numerical control machine to drill 0.30mm through holes in the six-layer rigid-flex printed circuit board. The structure of the rigid-flex board is a double-sided flexible board in the middle and double-sided rigid boards on both sides. The rigid board is Shengyi 35 / 0.5 / 35FR-4 double-sided copper-clad laminate, and the flexible board is Taihong 18 / 25 / 18 calendered PI halogen-free double-sided copper-clad laminate. Use the inventive method to remove drilling dirt, hole metallization, its technological process is as follows:

[0037] Step 1: Prepare two kinds of decontamination solutions;

[0038] Among them, the first decontamination solution contains 35g of sodium hydroxide or potassium hydroxide per liter, 20g of ethylene glycol ethyl ether used as an epoxy resin swelling agent, 2g of butanediol as a solubilizer, and 2g of butanediol as a polyimide swelling agent. 40ml of hydrazine, the rest is water; the second decontamination liquid contains 35g of ...

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Abstract

The invention relates to a method for cleaning through hole smears of a rigid-flexible printed circuit board, belonging to the field of printed circuit board manufacturing. The cleaning method comprises the following steps: 1) using a novel decontamination liquid to remove polyimide and acrylic resin smears and swell epoxy resin smears; 2) using a potassium permanganate decontamination liquid to oxidize and crack the swollen epoxy resin; and 3) using a sulfuric acid-sodium oxalate system to remove the residual potassium permanganate liquid, thereby realizing the removal of through hole smearsof the rigid-flexible board based on a low-valence chemical method, wherein every liter of decontamination liquid for removing polyimide and acrylic resin smears and swelling epoxy resin contains 20-50g of sodium hydroxide or potassium hydroxide, 10-40g of epoxy resin sweller, 1-5g of solubilizer, 10-60ml of polyimide sweller and the balance of water. The method provided by the invention realizesthe low-cost smear cleaning, and has the characteristics of simple method and high decontamination efficiency. By using the method to clean the through holes of the rigid-flexible printed circuit board, a level hole wall having good hole interlocking capability can be obtained.

Description

technical field [0001] The invention belongs to the field of printed circuit board manufacturing, and in particular relates to a method for cleaning (or removing) through-hole drilling stains of rigid-flexible circuit boards. Background technique [0002] The development trend of electronic products requires printed circuit boards to develop along the direction of "light, thin, short, small" and multi-functional. Rigid-flex printed circuit boards will become an important direction for the development of printed circuit boards due to their small size, light weight, avoiding wiring errors, increasing assembly flexibility, and realizing three-dimensional assembly. In the rigid-flex board, the electrical connection between layers and between the rigid board and the flexible board is mainly realized through metallized through holes in the rigid area. Because the rigid-flex printed circuit board dielectric substrate usually contains rigid board materials such as epoxy resin and g...

Claims

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Application Information

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IPC IPC(8): H05K3/26C11D7/12C11D7/32
Inventor 王守绪何为周国云黄志远陈亨书张建军
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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