Pick and Place Machine,Reflow Oven,Wave Soldering,Small Benchtop SMT,Stencil Printers,PCB Magazine Loader
Products Category
Contact Us

Name: Beijing Glichn S&T Development Co.,Ltd
Tel: +8610-65734544
Fax: +8610-65734544
Mobile: 13146162617
E-mail: info@smtchn.com;sales@smtchn.com
Add: Sales department: Floor 17th,Building No.6,Area 7th,ChaoXinJiaYuanDongLi,Chaoyang District,Beijing,China


• SMT technology • Package sizes introduction • Reworking defective SMD compon • Assembly components techniques • SMT placement equipment


PCB Hole Metallization (Plating)

Author:Glichn Date:7/23/2012 10:54:49 AM

Metallization and Plating

PCB (Printed Circuit Board) Hole Metallization and Copper Plating Process

The printed circuit board (PCB) copper plating include electroplating copper, tin electroplating, nickel and aurum electroplating etc. Among them copper electroplating is an important in the printed circuit board manufacture.

1 Dip circuit board into acid liquid

The purpose of dipping circuit board into acid liquid is to remove oxides on the plate surface, activate the board, usually concentration is 5%, and some are 10%, mainly to prevent the water into liquid container resulting sulfuric acid instability.

2 Make up electroplating liquid

Acid electronic liquid is made up of CuSO4, H2SO4, HCl and organic additives. CuSO4 liquid is main ingredients which is the main source of Cu+, CuSO4 concentration is important during making. Usually CuSO45H2O is 60g/L-100g/L. The amount of H2SO4 is about 180g/L-220g/L. Cl- content in the liquid is lower, it is about 30mg/L-80mg/L. Organic additives are transport agent, brightening agent, leveling agent and others. 

3 Electroplate

3.1 Full board electroplate copper

It also known as only copper, main function is protect thin electroless copper that just deposit. The process is take the whole board as cathode by thickening copper to a certain extent after hole metallization; then forming circuit line by etching that can prevent to waste products because of thin electroless copper layer which is etching in following process.

3.2 Secondary electroplate copper

It is also known as secondary copper or circuit copper. To meet rated current load, the thickness of each circuit line and hole metallization have to be up to requirement. The purpose of graphical electroplate is to add thickness.

4 Acid Degreasing

Degreasing is used to remove oxide, ink, glue or film on the surface of copper board to ensure the binding force between copper and graphical copper or nickel. The liquid has two kinds: acidic and alkaline, the alkaline agent is better, but why don’t use it? Because graphical and ink are not alkali, the alkaline agent will damage this line, please notice that using acidic degreasing agent during working. The liquid concentration is about 10%, time is less 6 min. Replacement is about 15m2/L, adding items is 0.5L-0.8L/100m2.

5 Etching

Etching is mainly used to clean the surface of copper board to ensure the binding force between graphical copper board and copper. Usually etching liquid is Na2S2O8, concentration is about 60g/L, time is about 20s, adding items is 3kg-4kg every 100m2; copper content is less than 20g/L.

Traditional hole metallization of printed circuit board is completed by electroless copper plating layer; more and more direct plating electroplating process is popular, it is not only simplifies the process, easy operation, also environmental; It will replace electroless copper process and become inevitable trend.