Development of functional electrodes for dissociation of water molecules and its applications to the electrochemical machining procesges in ultrapure water

提出并研制了能有效解离水分子的催化电极，用于超纯水中的超精密电解加工。成功地制备了表面羧化或磺化碳多晶电极，用这些表面修饰电极对铜多晶表面进行刻蚀，刻蚀速率达到了8 nm/S。特别是在使用表面磺化碳电极的情况下，以100%的电流效率获得了粗糙度为4 nm(Ra)的超光滑表面。另一方面，对于阴极金属或半导体的刻蚀工艺，我们采用胺化金电极，获得了0.2 nm/S的刻蚀速率。应用这些结果，提出了一种新的超精密加工方法，即在超纯水中分散表面改性的微细颗粒，并进行了试验。将直径为30 nm的表面胺化超细粒子分散在超纯水中，通过渗析将金属离子的杂质浓度降至ppb级。利用这种新的“电解液”，我们实现了硅表面的超清洁电化学刻蚀工艺。(001)面和(111)面的表面粗糙度分别为0.1228 nm(Ra)和0.064 nm(Ra)。最后，将所提出的新的电化学加工工艺应用于将电极的几何形状转录到铜、铝和钨表面。在使用直径为5 mm的细小颗粒的情况下，成功地实现了转录。

Catalytic electrodes which can dissociate water molecules effectively were proposed and developed for ultraprecision electrochemical machining processes in ultrapure water. Surface carboxylated or sulfonated carbon polycrystalline electrodes were successfully prepared and etching rate of 8nm/s was obtained far etching of Cu polycrystalline surface using these surface modified electrodes. Especially, in the case of using the surface sulfonated carbon electrodes, ultra-smooth surfaces whose roughness are 4nm (Ra) were obtained with 100% current efficiency. On the other hand, for the etching processes of cathode metal or semi-conductor, we used aminated gold electrodes, and etching rates of 0.2nm/s were obtained for the cathode AL. Applying these results, a new ultraprecision machining method in which using surface modified fine-particles dispersed in ultrapure water were proposed and tested. Surface aminated ultrafine particle whose diameters are 30nm were dispersed in ultrapure water and using dialysis the density of impurity of metal ions were lowered to ppb level. By using this new "electrolyte", we performed ultraclean electrochemical etching process of Si surfaces. The observed surface roughness for (001) and (111) surfaces were 0.1228nm (Ra) and 0.064nm (Ra), respectively. Finally, the present new electrochemical machining processes were applied to transcription of the geometry of electrodes to Cu, Al and W surfaces. In the case of using fine-particles whose diameters are 5mm, the transcriptions were successfully achieved.