Research And Application Of Additives In Electroless Copper Plating System Based On THPED

Electroless copper plating is widely used in electronic appliances,communications,machinery,aviation and other fields.The research on its formulation and process parameters is very important.Among them,complexing agents and additives are an indispensable part of the electroless copper plating solution.However,the application of traditional complexing agents such as tartrate is limited by temperature and cannot meet the industrial requirements of high-speed deposition;EDTA with a low reaction order has weak control over the copper plating reaction,and subsequent treatment of the plating solution is difficult.In recent years,tetrahydroxypropyl ethylene diamine(THPED),which has the characteristics of organic alkalis,as a new complexing agent can greatly improve the deposition rate of the system and the quality of the coating.At present,there are few targets for THPED as a single Research on complexing agent for copper plating.Based on the above point of view,this paper chooses THPED as the complexing agent to study the influence of single additive and additive compound on the electroless copper plating of THPED system,and optimize the process parameters.The silicon-based composite material is prepared by using the optimized copper plating system.Carry out photoelectrochemical performance research and realize the transition from theory to application.The main work content is as follows:(1)By comparing the effects of various additives on the deposition rate of the THPED system and the appearance of the coating,2,2'-bipyridine and K₄Fe(CN6) are selected as stabilizers,and N,N-dimethyl-dithioformamide C Sodium sulfonate(DPS)is an accelerator,and polyethylene glycol 6000 is a surfactant.2,2'-Bipyridine and K₄Fe(CN6) reduce the deposition rate of the reaction by 49.8%and 24.8%respectively by reducing the current density of the cathode and anode.Both stabilizers can refine the size of the deposited grains and make the coating show a(220)crystal plane nucleation tendency.A small amount of DPS can greatly accelerate the reaction process,so that the deposition rate reaches the maximum value of 14.80?m·h-1,and the obtained coating has a(111)crystal plane preferred orientation.Surfactant PEG-6000 inhibits the reduction reaction of copper ions,which reduces the reduction current by 34.7%and the deposition rate by 14.5%.The coating has a tendency to crystallize to the Cu(220)crystal plane,and the surface grain size of the coating is reduced from 87.9 nm to At 76.5 nm,the binding force increased from 0.83 k N·m^-1 to1.62 k N·m^-1.(2)The effect of a single additive on the THPED system is limited.The compound addition of 2,2'-bipyridine,K₄Fe(CN)₆,DPS and PEG-6000 can obtain a stable and high-speed copper plating system,and the compound additives The good synergistic effect enhances the nucleation tendency of the coating on the(111)crystal plane,the grain size is reduced to 51nm,and the binding force is increased to 4.33k N·m^-1,which effectively improves the surface deposition of the coating compared with a single additive.The optimized THPED copper plating process parameters are obtained through orthogonal experiments:0.055 mol·L^-1 Cu SO₄·5H₂O,0.060 mol·L^-1THPED,10m L·L^-1 HCHO(37%),0.2 mol·L^-1 Na OH,10 mg·L^-1 K₄Fe(CN)₆,0.6 mg·L^-1DPS,30 mg·L^-1 PEG-6000,water bath temperature is 50?.Comparing with the electroless copper plating solution on the market,it can be seen that in a short period of time,it can better meet the process requirements of high plating speed,and the obtained coating quality is good,and the surface deposition is uniform,smooth and detailed,and has a metallic luster.Potentially,it paves the way for the design of low-cost and high-efficiency electroless copper plating based on the combination of DPS additives and THPED complexing agent.(3)Using single crystal silicon as the substrate,firstly,silicon nano-arrays(Si NWs)are prepared on the planar single crystal silicon by the metal Ag-assisted etching method,and then the optimized THPED system is used to electroless copper plating on the Si NWs to realize the surface metal of the single crystal silicon The silicon-copper composite material is obtained by chemicalization,and the composite material is further oxidized to obtain Cu/Cu O@Si NWs composite material.The photocurrent density of this electrode is 0.15m A·cm^-2 under 1.23 V vs.RHE,and the lowest reflectivity is only 6%.The transfer resistance is only 5.1 K?,and the maximum light-to-hydrogen conversion efficiency is 0.057%,which is 24 times that of planar silicon light-to-hydrogen conversion efficiency and 3.7 times that of Cu O@Si NWs composite materials prepared by hydrothermal method.It has better photocurrent response and more The fast charge transfer kinetics proposes a simple and effective method for loading metal oxides on the surface of single crystal silicon.