PCB酸性蚀刻液中不同缓蚀剂对铜蚀刻的影响及模拟计算研究

Influence of Different Corrosion Inhibitors in PCB Acid Etching Solution on Copper Etching and Simulation Calculation Research

目的研究苯并三氮唑(BTA)、苯并咪唑(BZI)和2-巯基苯并噻唑(2-MBT)3种缓蚀剂对酸性蚀刻液中铜的蚀刻速率和蚀刻因子的影响及作用机理。方法采用静态挂片失重法计算蚀刻速率和缓蚀效率,利用金相显微镜测试蚀刻因子。通过塔菲尔极化曲线,研究缓蚀剂分子对铜腐蚀的影响。运用密度泛函理论,计算BTA、BZI、2-MBT的全局和局部反应活性。使用Forcite模块中的COMPASS力场进行分子动力学计算,研究缓蚀剂分子在Cu层表面吸附过程中的能量变化。结果缓蚀剂的加入,降低了铜的腐蚀速度,减缓了蚀刻速率,增大了蚀刻因子。实验结果显示,2-MBT存在时,缓蚀效率最大,铜的腐蚀速度最小,蚀刻因子最佳。全局反应活性分析表明,3种缓蚀剂分子对铜的缓蚀效率关系为2-MBT>BZI>BTA;局部反应活性分析表明,2-MBT的活性主要集中在2个S原子上,S(9)可以接受电子,形成反馈键,S(10)能够提供电子,形成配位键。分子动力学计算结果表明,BTA、BZI、2-MBT均能自发吸附在铜层表面,且在Cu(111)面的吸附能分别为–2927.04、–3033.94、–3097.58 kJ/mol,表明3种缓蚀剂分子均易吸附在铜层表面,进而在一定程度上抑制铜的腐蚀。结论在酸性蚀刻液中加入缓蚀剂,能有效提高蚀刻因子。当缓蚀剂分子中的活性原子同时包含亲核中心和亲电中心时,效果更好。

The work aims to study the effect of benzotriazole(BTA),benzimidazole(BZI)and 2-mercaptobenzothiazole(2-MBT)on the etching rate and etching factors of copper in acid etching solutions mechanism.Static weight-loss method was used to calculate the etching rate and inhibiting efficiency.The etching factor was measured by metallographic microscope.The effect of corrosion inhibitor molecules on copper corrosion was investigated through Tafel polarization curve.The global and local reactivity of BTA,BZI and 2-MBT inhibitors were calculated by density functional theory.COMPASS force field in Forcite module was used for molecular dynamics calculation to study the energy change of corrosion inhibitor molecules in the surface adsorption process of Cu layer.The results show that the addition of corrosion inhibitor can reduce the corrosion rate of copper,slow down the etching rate,and increase the etching factor.The experimental results indicate that the corrosion inhibition efficiency is the largest,copper corrosion rate is the smallest,and the etching factor is the best in the presence of 2-MBT.The analysis of global reactivity shows that the inhibition efficiency of the three inhibitor molecules is 2-MBT>BZI>BTA.Local reactivity analysis shows that the activity of 2-MBT is mainly concentrated on two S atoms,S(9)can accept electrons to form feedback bonds,and S(10)can provide electrons to form coordination bonds.The results of molecular dynamics calculations show that BTA,BZI,and 2-MBT can spontaneously adsorb on the surface of the copper layer,and the adsorption energy on the Cu(111)plane is–2927.04,–3033.94,and–3097.58 kJ/mol,respectively,indicating that the three inhibitor molecules are easily adsorbed on the surface of the copper layer,thereby inhibiting copper corrosion to a certain extent.Adding a corrosion inhibitor to the acid etching solution can effectively improve the etching factor.The effect is better when the active atoms in the corrosion inhibitor molecules have both nucleophilic centers and electrophilic centers.