賽森電子科技告訴你磁控濺射的種類Cycas Microelectronics tells you the type of magnetron sputtering

磁控濺射包括很多種類。各有不同工作原理和應用對象。但有一共同點:利用磁場與電場交互作用，使電子在靶表面附近成螺旋狀運行，從而增大電子撞擊氬氣產生離子的概率。磁控濺射臺所產生的離子在電場作用下撞向靶面從而濺射出靶材。

靶源分平衡和非平衡式，平衡式靶源鍍膜均勻，非平衡式靶源鍍膜膜層和基體結合力強。平衡靶源多用于半導體光學膜，非平衡多用于磨損裝飾膜。磁控陰極按照磁場位形分布不同，大致可分為平衡態和非平衡磁控陰極。平衡態磁控陰極內外磁鋼的磁通量大致相等，兩極磁力線閉合于靶面，很好地將電子/等離子體約束在靶面附近，增加碰撞幾率，提高了離化效率，因而在較低的工作氣壓和電壓下就能起輝并維持輝光放電，靶材利用率相對較高，但由于電子沿磁力線運動主要閉合于靶面，基片區域所受離子轟擊較小.非平衡磁控濺射技術概念，即讓磁控陰極外磁極磁通大于內磁極，兩極磁力線在靶面不完全閉合，部分磁力線可沿靶的邊緣延伸到基片區域，從而部分電子可以沿著磁力線擴展到基片，增加基片區域的等離子體密度和氣體電離率.不管平衡非平衡，若磁鐵靜止，其磁場特性決定一般靶材利用率小于30%。為增大靶材利用率，可采用旋轉磁場。但旋轉磁場需要旋轉機構，同時濺射速率要減小。旋轉磁場多用于大型或貴重靶。如半導體膜濺射。對于小型設備和一般工業設備，多用磁場靜止靶源。

用磁控靶源濺射金屬和合金很容易，點火和濺射很方便。這是因為靶(陰極)，等離子體，和被濺零件/真空腔體可形成回路。但若濺射絕緣體如陶瓷則回路斷了。于是人們采用高頻電源，回路中加入很強的電容。這樣在絕緣回路中靶材成了一個電容。但高頻磁控濺射電源昂貴，濺射速率很小，同時接地技術很復雜，因而難大規模采用。為解決此問題，發明了磁控反應濺射。就是用金屬靶，加入氬氣和反應氣體如氮氣或氧氣。當金屬靶材撞向零件時由于能量轉化，與反應氣體化合生成氮化物或氧化物。

磁控反應濺射絕緣體看似容易,而實際操作困難。主要問題是反應不光發生在零件表面，也發生在陽極，真空腔體表面，以及靶源表面。從而引起滅火，靶源和工件表面起弧等。德國萊寶發明的孿生靶源技術，很好的解決了這個問題。其原理是一對靶源互相為陰陽極，從而消除陽極表面氧化或氮化。

冷卻是一切源(磁控，多弧，離子)所必需，因為能量很大一部分轉為熱量，若無冷卻或冷卻不足，這種熱量將使靶源溫度達一千度以上從而溶化整個靶源。

There are many kinds of magnetron sputtering. There are different working principles and application objects. But there is one thing in common: using the interaction of magnetic field and electric field, the electrons move in a spiral shape near the target surface, thus increasing the probability of electrons impacting argon to produce ions. The ions produced by the magnetron sputtering platform hit the target surface under the action of electric field, thus splashing out the target. 

The target source is divided into equilibrium and non-equilibrium type, the equilibrium type target source coating is uniform, and the non-equilibrium type target source coating has strong binding force with the substrate. The balanced target source is mainly used for semiconductor optical films, and the unbalanced target source is mainly used for wear decorative films. According to the different distribution of magnetic field configuration, the magnetron cathodes can be roughly divided into equilibrium and non-equilibrium. The magnetic flux of the inner and outer magnetic steel of the balanced magnetic control cathode is approximately the same, the two pole magnetic field lines are closed to the target surface, which confines the electron / plasma to the target surface well, increases the collision probability, and improves the ionization efficiency. Therefore, the glow discharge can be started and maintained under the lower working pressure and voltage, and the utilization ratio of the target material is relatively high, but the movement of the electron along the magnetic field lines is mainly closed to The concept of unbalanced magnetron sputtering technology is that the magnetic flux of the outer pole of the magnetron cathode is larger than that of the inner pole, the magnetic field lines of the two poles are not completely closed on the target, some of the magnetic field lines can extend to the substrate along the edge of the target, so some electrons can extend to the substrate along the magnetic field lines, increasing the plasma density and gas ionization rate in the substrate area Whether the balance is unbalanced or not, if the magnet is stationary, its magnetic field characteristics determine that the utilization rate of the general target is less than 30%. In order to increase the utilization ratio of the target, the rotating magnetic field can be used. But the rotating magnetic field needs a rotating mechanism, and the sputtering rate should be reduced. Rotating magnetic field is mostly used for large or valuable targets. Such as semiconductor film sputtering. For small equipment and general industrial equipment, magnetic static target source is used.

 It is easy to sputter metals and alloys with magnetron target source, and easy to ignite and sputter. This is because the target (cathode), plasma, and splashed parts / vacuum cavity can form a circuit. But if sputtering insulator such as ceramic, the circuit will be broken. So people use high-frequency power supply, and a strong capacitance is added to the circuit. In this way, the target becomes a capacitor in the insulating circuit. However, the high frequency magnetron sputtering power supply is expensive, the sputtering rate is very small, and the grounding technology is very complex, so it is difficult to use it on a large scale. In order to solve this problem, magnetron reactive sputtering was invented. It is to use metal target, add argon and reaction gas such as nitrogen or oxygen. When the metal target collides with the part, it combines with the reaction gas to form nitride or oxide due to energy conversion. 

Magnetron reactive sputtering insulator seems easy, but it is difficult to operate. The main problem is that the reaction occurs not only on the surface of parts, but also on the surface of anode, vacuum cavity and target source. So as to cause fire-extinguishing, arc on target source and workpiece surface, etc. The twin target source technology invented by German LeiBao solves this problem well. The principle is that a pair of target sources are cathode and anode to each other, so as to eliminate anodizing or nitriding on the anode surface. 

Cooling is necessary for all sources (magnetically controlled, multi arc, ion), because a large part of energy is converted into heat. If there is no cooling or insufficient cooling, this heat will make the target temperature reach more than 1000 degrees and dissolve the whole target.