Study on Narrow Tube Inner Coating Method by Harmonic ECR Plasma

针对窄管内壁镀膜，研究了磁场中微等离子体，特别是二次谐波电子回旋共振（ECR）等离子体的脉冲同轴溅射工艺。在二次谐波ECR条件下，电子的共振约束导致了有趣的微等离子体特性：与ECR条件相比，更高的电子密度、更低的等离子体电势、更低的电子温度和更低的有效功率吸收.通过对靶离子电流和电压随时间的变化的详细研究，发现了脉冲偏压和间隙长度的选择规律.在均匀型下测量了靶离子流，离子流随靶偏压的增加而减小。护套宽度的扩大可以被认为是这个原因。当比较均匀型和镜面型时，可以理解离子电流密度的趋势是相同的。但是，离子流密度高于均匀型。认为镜面型离子流密度的增加是由于镜面效应减少了轴向电子损失所致。结果表明，等离子体密度高于均匀型等离子体密度，并成功地用氩气在内径为1mm的绝缘细管内表面溅射镀制了Au膜。并利用扫描镜式磁场对40mm长的窄管进行了内镀。

For the inner surface coating of narrow tubes, we have investigated pulsed coaxial sputtering process with the micro plasmas in a magnetic field, especially, the 2nd harmonic electron cyclotron resonance (ECR) plasmas. Resonant confinement of electrons at the 2nd harmonic ECR leads to interesting micro plasma characteristics: the higher electron density, the lower plasma potential, the lower electron temperature and the effective power absorption compared with ECR condition.As a result of detailed investigation of temporal evolutions of the target ion current and voltage, we found that the selection rule of pulse bias voltage and gap length. The target ion current was measured at uniform type, and the ion current is decreased with increasing the target bias voltage. Expansion of a sheath width can be considered as this reason. When the uniform type and the mirror type are compared, it is understood that the tendency to the ion current density was the same. However, the ion current density was higher than that of uniform type one. It is considered that the increase of ion current density in mirror-type is caused by decreased axial electron loss by mirror effect. From this result, it is understood that plasma density was higher than that of uniform type one.As a result, we have succeeded in sputter coating of Au films onto the inner surface of insulated narrow tube with 1mm inner diameter by using Xe gas. And it was performed that inner coating of narrow tube with 40mm length by using scanning-mirror-type magnetic field.