PCB Tech - PCB process PCB board cleaning process detailed explanation

PCB process PCB board cleaning process detailed explanation

1. Cutting: cutting a large sheet of material into small pieces of material needed

Wash board: Wash the dust and impurities on the board machine and air dry.
2. The inner layer of dry film: paste a layer of photosensitive material on the copper foil of the board, and then use the black film for alignment exposure and development to form a circuit diagram.
Chemical cleaning:
(1) Remove oxides, garbage, etc. on the Cu surface; if the Cu surface is rough, it can enhance the bonding force between the Cu surface and the photosensitive material.
(2) Process: Degreasing-water washing-micro erosion-high pressure water washing-circulating water washing-water absorption-strong wind drying-hot air drying.
(3) Factors affecting plate washing: degreasing speed, degreasing agent concentration, micro-etching temperature, total acidity, Cu2+ concentration, pressure, speed.
(4) Defects are easy to produce: open circuit-poor cleaning effect, resulting in film throwing; short circuit-dirty cleaning produces garbage.
3. Immersion copper and board power

4. Outer dry film
5. Pattern electroplating: Carry out the hole and circuit circuit to complete the copper plating thickness requirement.
(1) Degreasing: remove the surface oxide layer and surface pollutants;
(2) Acid leaching: remove pollutants in the pretreatment and copper tank;
6. Circuit board electricity gold:
(1) Degreasing: Remove grease and oxides on the surface of the circuit diagram to ensure that the copper surface is clean.
7. Wet green oil:
(1) Pre-treatment: Remove the surface oxide film and roughen the surface to enhance the bonding force between the green oil and the circuit board surface.
8. Tin spraying process:

(1) Hot water washing: clean the dirt and some ions on the surface of the circuit board;
(2) Scrubbing: further clean the residues left on the surface of the circuit board.
9. Immersion gold craft:
(1) Acidic degreasing: remove light grease and oxides on the copper surface to activate and clean the surface to form a surface state suitable for nickel and gold plating.
10. Shape processing
(1) Wash the board: remove surface contaminants and dust. 11. NETEK copper surface treatment

(1) Degreasing: Remove grease and oxides on the surface of the circuit diagram to ensure that the copper surface is clean.

Steps to clean the copper surface:
1. Dry film pressing
2. Before the inner layer oxidation treatment

3. After drilling (remove the slag, remove the colloid produced during the drilling process to make it coarser and clean) (mechanical grinding plate: use ultrasonic cleaning to fully clean the hole, and the copper powder and adhesion in the hole Sex particles are removed)
4. Before chemical copper
5. Before copper plating
6. Before the green paint
7. Before spraying tin (or other solder pad processing procedures)
8. Gold finger before nickel plating

Secondary copper pretreatment:
Degreasing-washing-micro-etching-washing-acid immersion-copper plating-washing the surface of the board surface impurities such as oxidation, fingerprints, and minor objects that may be left on the surface of the outer circuit manufacturing plant of the previous process Remove. And activated with the surface, so that the copper plating adhesion is good.
A cleaning is required before shipment to remove ion contamination.

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