The main factors affecting PCB OSP film thickness:
1. The concentration of the main components of OSP: Alkylbenzimidazole or similar components (imidazoles) are the main components in the OSP liquid, and the concentration is the fundamental factor in determining the thickness of the OSP.
2. Organic acid: The addition of organic acid can increase the solubility of alkylbenzimidazole in aqueous solution and promote the formation of a complex protective film. However, excessive dosage will dissolve the protective film deposited on the copper surface, so it is crucial to control the amount of organic acid added (i.e., the pH value). High pH values can decrease the solubility of alkylbenzimidazole and cause oily matter to precipitate out, hindering the dipping process. Maintaining a reasonable pH level can result in a dense, uniform, and moderately thick complex film. Conversely, a low pH level can increase the solubility of the complex film, leading to its dissolution on the copper surface and failure to achieve the desired thickness.
3. Dip coating time: With specific OSP bath composition, temperature, and pH values, the thickness of the complex protective film initially increases linearly with the duration of dip coating, but then plateaus after a certain point. Extending the dip coating time beyond this threshold does not significantly increase the film thickness.
4. Pre-soaking: Pre-soaking helps prevent harmful ions like chloride ions from damaging the OSP tank solution. Additionally, the presence of copper ions in the prepreg solution can expedite the formation of the complex protective film and shorten the dip-coating time. The copper ions are believed to form complexes with alkylbenzimidazole in the pre-flux solution, which accelerates the deposition of a thicker protective layer on the copper surface. However, as the content of alkylbenzimidazole in the prepreg is minimal, excessive copper ions can hasten the aging of the solution and necessitate its replacement. The OSP prepreg cylinder primarily serves to enhance film thickness and counteract the effects of harmful ions. It is advisable to optimize the syrup performance and minimize the reliance on the prepreg tank to reduce costs.
1. The concentration of the main components of OSP: Alkylbenzimidazole or similar components (imidazoles) are the main components in the OSP liquid, and the concentration is the fundamental factor in determining the thickness of the OSP.
2. Organic acid: The addition of organic acid can increase the solubility of alkylbenzimidazole in aqueous solution and promote the formation of a complex protective film. However, excessive dosage will dissolve the protective film deposited on the copper surface, so it is crucial to control the amount of organic acid added (i.e., the pH value). High pH values can decrease the solubility of alkylbenzimidazole and cause oily matter to precipitate out, hindering the dipping process. Maintaining a reasonable pH level can result in a dense, uniform, and moderately thick complex film. Conversely, a low pH level can increase the solubility of the complex film, leading to its dissolution on the copper surface and failure to achieve the desired thickness.
3. Dip coating time: With specific OSP bath composition, temperature, and pH values, the thickness of the complex protective film initially increases linearly with the duration of dip coating, but then plateaus after a certain point. Extending the dip coating time beyond this threshold does not significantly increase the film thickness.
4. Pre-soaking: Pre-soaking helps prevent harmful ions like chloride ions from damaging the OSP tank solution. Additionally, the presence of copper ions in the prepreg solution can expedite the formation of the complex protective film and shorten the dip-coating time. The copper ions are believed to form complexes with alkylbenzimidazole in the pre-flux solution, which accelerates the deposition of a thicker protective layer on the copper surface. However, as the content of alkylbenzimidazole in the prepreg is minimal, excessive copper ions can hasten the aging of the solution and necessitate its replacement. The OSP prepreg cylinder primarily serves to enhance film thickness and counteract the effects of harmful ions. It is advisable to optimize the syrup performance and minimize the reliance on the prepreg tank to reduce costs.
