Inner Brown Oxide Solution

Inner Brown Oxide Solution

The brown oxide solution is the core processing step of the browning process. The copper surface of the inner surface of the circuit board enters the tank after acid-base cleaning and activation, and is processed into a brown and uniformly apparent organic metal layer. The microscopic rough structure of the organic metal layer strengthens the bonding force between the copper surface and the prepreg during the pressing process, and ensures good thermal shock resistance and chemical attack resistance in the subsequent stages.

1) Product Feature

1. Generate an organic metal coating on the copper surface;
2. Based on the corrosion of copper crystal lattice based on sulfuric acid hydrogen peroxide system, the microstructure is optimized to improve the bonding force of the inner layer;
3. Compared with the black oxidation process, it has better acid resistance and almost no "pink circles" and "wedge-shaped voids";
4. Highly concentrated liquid, easy to operate and store;
5. The highest copper ion concentration can reach 30g/L, usually within 28g/L for long-term stable operation;
6. It is suitable for horizontal transmission production line.

2) Equipment Requirement & Recommendation

3) Composition of Bath

The tank matching parameters of the inner brown oxide solution are as follows

Slot Matching Steps:

①Clean the tank
②Calculate the required addition amount of each component according to the specific tank volume and the parameters in the above table
③Add deionized water about half of the tank volume
④Add 50% sulfuric acid according to the calculated amount and stir well
⑤Add the inner browning agent and 35% hydrogen peroxide in order
⑥ Replenish water to the corresponding tank volume scale
⑦ Heat to the set temperature and prepare for production

4）Operating Parameters

The operating control parameters of the inner brown oxide solution are as follows

5) Process Control & Maintenance

①Add parameters

Mode 1 (steady state operation): the steady state operation mode of automatically adding the emission system (recommended)

It is recommended to use an automatic addition and discharge system. The system automatically discharges a certain amount of old working fluid every time a certain area of the board is produced during the steady-state production process, and then the system automatically adds fresh components into the tank according to the set amount. The discharge amount varies according to the control concentration of copper ions, and needs to be fine-tuned according to the area of residual copper on the board. Under normal circumstances, 30-50 liters of working fluid needs to be replaced for every 100 square meters (cutting area) circuit boards produced. In this mode, in principle, sustainable production is possible without opening a new tank, but it is still necessary to regularly withdraw the potion in the tank, clean and maintain the tank, and then pump the potion back to continue production after maintenance.
Note: It is recommended to measure and analyze each parameter in each shift. According to the analysis results, sulfuric acid, hydrogen peroxide and U-Bond® MT 50 can be adjusted. If it is found that there is a trend of insufficient or excessive addition of components, the automatic addition parameters should be adjusted appropriately. This phenomenon is related to the difference in the residual copper area of different batches of boards.

Mode 2 (Single-tank operation): Single-tank operation mode without automatic addition of an exhaust system

Without the control of an automatic emission system, the concentration of copper ions cannot be stabilized at a certain set value. When the copper ion exceeds 30g/L, the tank needs to be re-allocated. The tank life in single-cylinder operation mode is approximately 2.5 square meters per liter of working fluid.

The adding parameters of the inner brown oxide solution are recommended as follows:

②Maintenance

Periodic equipment cleaning and maintenance are necessary. For steady-state operation in mode 1, cleaning and maintenance are required at least four weeks. For single-cylinder operation in mode 2, cleaning and routine maintenance are required before each cylinder is opened.

③Water quality requirements
Deionized water is required for the browning tank and the front and back washing tanks. The chloride ion content should be controlled within 5ppm.

6) Product Characteristic & Storage Condition

①Inner Brown Oxide Solution: Specific gravity: 1.07-1.13 g/mL
②Storage conditions: 5℃-40℃, avoid heat and direct sunlight.

7) Safety Guidelines

①Avoid direct contact with this chemical.
②Do not breathe its vapor.
③Wash contaminated clothing before reuse.
④Before using or coming into contact with this chemical, please read the relevant Material Safety Data Sheet (MSDS) carefully. Please ask for relevant information from the relevant customer service staff