【作者】 刘鹤；

【导师】 贺岩峰；

【作者基本信息】 长春工业大学 ， 化学工程， 2011， 硕士

【摘要】 化学镀镍,其本质是在基材表面的自催化作用下,镀液中的Ni2+获得还原剂提供的电子,沉积到基材上的一种氧化还原反应。碱性化学镀镍,可以实现低温下操作,并获得低磷含量的镀层。硅,作为太阳能电池、微电子器件和集成电路的主要材料,在其进行表面改性时,多经过氢氟酸和硝酸的预处理,操作环境受到很大影响。本文的研究是,中低温下,经过不含氟化物溶液的简单预处理,通过碱性化学镀镍工艺,半导体硅表面获得导电性和结合力良好的Ni-P合金镀层。选择适合碱性化学镀的络合体系。对于络合剂的选择,本文先后试验了柠檬酸、焦磷酸钠、辅助络合剂、硼砂等试剂。或单独使用,例如,单独使用柠檬酸作为络合剂,研究其最小用量；或进行组合使用,例如,柠檬酸+辅助络合剂、柠檬酸+硼砂、柠檬酸+焦磷酸钠组成不同的络合体系,进行相关实验。根据镀液的稳定性、镀速、镀层质量来判断这些络合体系,最终确定柠檬酸+辅助络合剂的络合体系较适合碱性化学镀液。通过一系列实验,研究了温度的变化对镀液的稳定性、镀速、镀层质量的影响,进而调整柠檬酸与辅助络合剂的配比,及相关操作条件,得到30-90℃各温度下的适宜络合体系。低温化学镀工艺的研究。在40℃左右的低温下,根据GB/T 17359-98.GB/T 13913标准,通过EDX和ICP的方法,对镀层中磷的质量含量进行了定性和定量分析。本文先后研究了柠檬酸、辅助络合剂、次亚磷酸钠的用量和温度、pH对镀层磷含量的影响,得到一系列的相关曲线,进而对镀液组成和操作条件进行调整,以得到低磷镀层。综合考虑镀速、镀液稳定性和镀层的磷含量,本文得到了一种新的低温低磷碱性化学镀镍液配方,并证明低温高pH的条件下易获得低磷镀层。以中低温碱性化学镀镍液的配方为基础,在P111、N111、N100单晶硅上直接进行镍的化学沉积,并研究了柠檬酸、辅助络合剂的用量和温度、pH对镀速和镀层结合力的影响。通过调整这些工艺参数,使得镀层结合力增强,从而降低镀层与硅之间的接触电阻,因为结合力的好坏对接触电阻有直接的影响。此外,在碱性的化学镀溶液中,阴离子性的表面活性剂有利于镍在基材表面的均匀沉积,使得镀层与基材之间的结合更充分、紧密。因此,本文在硅的碱性化学镀镍溶液中添加了十二烷基硫酸钠,探索了该表面活性剂的用量对镀层结合力的影响,并得到其最佳用量。最终,本文得到一种新的适用于多种型号半导体硅,可得到结合力良好镀层的中温碱性化学镀镍液配方。更多还原

【Abstract】 Electroless plating, under the catalytic form the surface of the substrate,Ni2+ in the bath provided electronic by a reducing agent, deposition to the substrate,is a redox reaction.Alkaline plating, can operate at low temperature and get low phosphorus coating.Silicon, as the main material of solar cells, microelectronics devices and integrated circuits,in their surface modification, is almost pretreated with the mixture of hydrofluoric acid and nitric acid, and the operating environment has been greatly affected.This study is,under the low temperature, after a simple pretreatment solution without fluoride,the Ni-P alloy coating with good electrical conductivity and adhesion,is obtained on the silicon surface through the alkaline electroless nickel plating,.Choosing complex system of the electroless plating bath.For the choice of complexing agent, the paper has tested citric acid, sodium pyrophosphate, auxiliary complexing agent, borax and other reagents.Or alone, for example, citric acid as a complexing agent,is used alone to study the minimum amount; or in combination, for example, complex system composed of citric acid+auxiliary complexing agent, citric acid+borax, citric acid+sodium pyrophosphate,is used for the associated experiment.The complex system is determined according to the bath stability, deposition rate and the quality of the coating, and ultimately the complex system composed of citric acid+auxiliary complexing agent, is more suitable for alkali chemical bath.Through a series of experiment to study the influence of the temperature on stability of the plating bath, plating rate and quality of coating, the ratio of citric acid and auxiliary complexing agent, and related operating conditions will be adjusted to obtain the appropriate complex system under 30-90℃.Research on low-temperature electroless plating.At low temperature around 40℃, according to GB/T 17359-98, GB/T 13913 standard, by EDX and ICP method, mass content of phosphorus in the coating is studied in a qualitative and quantitative analysis.This paper has studied the affection of the concentration of citric acid, auxiliary complexing agent, sodium hypophosphite in the bath,and temperature, pH of the bath on the phosphorus content of the coating,to get a list of related curves, and then the bath composition and operating conditions will be adjusted to attain low phosphorus coating.Considering the plating rate, bath stability and phosphorus content of the coating, the paper has found a new low phosphorus electroless nickel alkaline solution and proved that low-phosphorus coating is easy to obtain under the conditions of low temperature and high pH. For the low-temperature alkaline electroless nickel plating onto the P111, N111, N100 silicon,the paper studied the affection of the citric acid, auxiliary complexing agent, and temperature, pH on the plating rate and adhesion of the coating.After adjusting the parameters of the plating, the binding becomes better, and the contact resistance between the coating and the silicon surface reduces because the binding force of the coating has a direct impact, the contact resistanceIn addition, in an alkaline electroless nickel plating solution, the anionic surfactant is conducive to attain uniform Ni coating on the substrate surface, making the combination between the coating and the substrate better.Therefore, in the alkaline electroless nickel solution, sodium dodecyl sulfate is added to study the affection of it on the coating adhesion and get the best concentration.Finally, this paper obtained a new alkaline electroless nickel plating solution,that is used for variety type silicon and gets good adhesion coating.更多还原