Study on Narrow Tube Inner Coating Method by Harmonic ECR Plasma

对于窄管内表面涂层，我们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。二次谐波 ECR 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，电子密度更高、等离子体电势更低、电子温度更低、有效功率吸收也更低。通过对目标离子电流和电压的时间演变进行详细研究，我们发现了脉冲偏置电压和间隙长度的选择规则。目标离子电流以均匀类型测量，离子电流随着目标偏压的增加而减小。其原因可以认为是护套宽度的扩大。当比较均匀型和镜面型时，可知离子电流密度的趋势相同。然而，离子电流密度高于均匀型一。认为镜型离子电流密度的增加是由于镜效应减少了轴向电子损失造成的。从该结果可以看出，等离子体密度比均匀型等离子体密度高。结果，我们成功地使用Xe气，在内径1mm的绝缘细管的内表面上溅射了Au膜。利用扫描镜式磁场对40mm长的细管进行内涂层处理。

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.