PCB Technical - PCBA black holeization process technology introduction

I. Overview

The emergence of PCBA black hole direct electroplating is a challenge to traditional PTH. Its biggest feature is to replace the traditional electroless copper plating process, and the conductive film formed by physical action can be directly transferred to electroplating. From an efficiency point of view, due to the simplified process procedures and reduced control factors, compared with the traditional PTH manufacturing procedures, the number of drugs used is reduced and the production cycle is greatly shortened. Therefore, the production efficiency is greatly improved, and the sewage treatment costs are reduced. The total cost of printed circuit board manufacturing is reduced.

Second, the characteristics of PCBA black hole direct plating

1. PCBA black hole solution does not contain traditional electroless copper plating components, and eliminates the use of formaldehyde and environmentally harmful chemicals such as EDTA, NTA, EDTP, etc. in the formulation, which is an environmentally friendly product.

2. The process flow is simplified. The PCBA black hole process takes only 12 minutes, instead of the extremely thin and difficult-to-control intermediate layer (electroless copper plating), thereby improving the adhesion of electroplated copper and improving the metallization of PCB/FPC holes. reliability.

3. The analysis, maintenance and management procedures of the solution are greatly simplified.

4. Compared with the traditional PTH, the operation is convenient, the production cycle is short, and the waste treatment cost is reduced, thereby reducing the total cost of production.

5. Provides a new technological process-selective direct electroplating.

3. PCBA black hole direct electroplating technology

3.1 The principle of PCBA black holeization

It is to dip fine graphite and carbon black powder on the hole wall to form a conductive layer, and then conduct direct electroplating. Its key technology is the composition of the black hole solution. First, the fine graphite and carbon black powder are uniformly dispersed in the medium, namely deionized water, and the surfactant in the solution is used to stabilize the uniformly distributed graphite and carbon black particles in the solution, and at the same time, it has good wetting performance, so that Graphite and carbon black can be fully absorbed on the surface of the non-conductor hole wall to form a uniform, fine, and firmly bonded conductive layer.

3.2 Composition

PCBA black porosification solution is mainly composed of fine graphite and carbon black powder (particle diameter of 0.2-0.3μm), liquid dispersion medium, deionized water and surfactants.

3.3 The role of various ingredients

(1) Graphite and carbon black powder: it is the main part of the PCBA black porosification solution, which plays a conductive role.

(2) Liquid dispersion medium: high-purity deionized water used to disperse graphite and carbon black powder.

(3) Surfactant: The main function is to improve the stability and wettability of graphite and carbon black suspensions.

(4) Process conditions: PH value: 9.5-10.5, operating temperature: 25-32 degrees.

(5) The best treatment area: 300-600cm2/g.

3.4 Selection and adjustment of the components of PCBA black pore solution

(1) The surfactant used, whether it is cationic, anionic or nonionic surfactants, can be used, but it must be soluble, stable and able to form a uniform liquid with other ingredients.

(2) In order to improve the stability of PCBA black hole solution, it is best to use potassium hydroxide or reagent ammonia to adjust the pH value of the solution.

(3) Use deionized water as the dispersion medium of PCBA black porosification solution.

3.5 PCBA black holeization process and process description

(1) Cleaning the whole hole treatment-water cleaning-PCBA black hole treatment-drying-micro-etching water cleaning-copper electroplating.