Influence Of Non-ionic Surfactant On Electroless Copper

In recent years, electroless copper have important applications in circuit board PCB through-hole plating. Hole within the insulating layer and the copper layer alternately exist to achieve the hole circuit is turned on, metal treatment on the pore wall. Hole metallization process, often there will be bad copper layer toughness, since plated slow, hole liquid exchange adverse affect the quality of the hole copper. In order to overcome the electroless copper hole wall rupture, and PTH is not complete and other issues, the topics put forward a non-ionic surface active agent to improve the toughness of the copper layer and from the plating capacity to meet the hole copper requirements. Electroless copper plating was carried out on the brass sheet substrate. The basic bath composition and process conditions are as follows:CuSO4·5H2O lOg/L, EDTA-2Na40g/L, NaOH12g/L, HCHO10ml/L, pH13.0, and temperature35℃. Effects of non-ionic surfactant such as OP-10、AEO9、polyoxyethylene amide、Triton X-100、Tween-80and polyethyleneglycol, anionic surfactant such as sodium dodecyl benzene sulfonate(SDBS)、lauryl sodium sulfate and sodium dodecylsulpHate(SDS), the compound surfactant such as fatty alcohol polyoxyethylene ether compound with polyoxyethylene amide、polyethyleneglycol、Triton X-100respectively on the starting time of copper deposition, deposition rate, ductility and grain refinement of coatings were studied. Results shows that:(1)When the mass concentration is small (less than10mg/L), the kinds of surfactants can reduce copper deposition rate and improve the ductility,such as OP-10、AEO9、Triton X-100、fatty alcohol polyoxyethylene ether compound with Polyoxyethylene amide、 polyethyleneglycol, Triton X-100respectively.(2)The first of refine the grain ability is Triton X-100,the secondly is Tween-80, the last one is OP-10.(3) The surfactants are in the form of mixed in the copper.(4) When it is not added surfactants, the starting time of copper deposition is shorter.The addition with AEO9、OP-10; polyethyleneglycol、Tween-80、Triton X-100, the starting time of copper deposition is delayed. From equilibrium potential and plating time comprehensive judgment, the surfactant adsorption ability of the order is:the AEO9<OP-10, polyethylene glycol< Tween-80<Triton X-100.Tween-80can reduce the deposition rate significantly but has little impact on ductility of copper coating. Compared to Triton X-100and Tween-80, OP-10is the favorable agent for ductility improvement of copper coatings. Most of the presence of surfactant is unfavorable for coating corrosion resistance, however, When the mass concentration of OP-10is less than3mg/L,the copper coating has anticorrosion effect on the sulfuric acid solution. Because of the weak adsorption capacity, it has little impact of electroless plating copper cathode polarization with OP-10. When the mass concentration of AEO9is10mg/L(or20mg/L), the cathode current is increased, which is beneficial to the deposition of copper.