磁控溅射靶材刻蚀特性的模拟研究

靶材刻蚀特性是研究磁控溅射靶材利用率、薄膜生长速度和薄膜质量的关键因素.本文用有限元 分析软件ANSYS模拟了磁控溅射放电空间的磁场分布,用粒子模拟软件OOPIC Pro(object oriented particle in cell)模拟了放电过程,最后用SRIM(stopping and range of ions in matter)模拟了靶材的溅射特性,得到了靶材的刻蚀形貌和刻蚀速度,并讨论了不同工作气压和不同阴极电压对靶材刻蚀的影响.模拟结果表明:靶材刻蚀形貌与磁场分布有关,磁通密度越强,对应的靶材位置刻蚀越深;靶材的刻蚀速度随阴极电压的增大而增大,而当工作气压增大时,靶材的刻蚀速度先增大后趋向平衡,当工作气压超过一定的值时,刻蚀速度随气压的增大开始减小.模拟结果与实验观测进行了比较,二者符合较好.     

直流磁控溅射中磁场强度和阴极电压对圆平面靶刻蚀形貌的影响

本文借助Comsol和Matlab软件模拟了直流磁控溅射圆平面靶系统的磁场分布和荷电粒子分布,对不同磁场强度和阴极电压条件下的荷电粒子分布进行了模拟分析,通过比较靶面离子流密度分布曲线发现:当磁场强度增强时,靶面离子流密度分布曲线会变得更加陡窄;当阴极电压变化时,靶面离子流密度分布曲线几乎没有变化.说明靶材的刻蚀形貌会随磁场强度增强而变窄,而阴极电压变化对靶材的刻蚀形貌没有影响.上述结论对直流磁控溅射工艺参数优化具有一定的理论指导意义.     

直流磁控溅射中矩形平面靶刻蚀形貌的数值计算及优化

对普通矩形平面靶的磁场分布、电子运动轨迹和电子分布进行了理论计算。通过磁场的解析表达式,解出电子在磁场中的运动方程,求得并从理论上解释了电子的运动轨迹。由电子的运动轨迹,并运用Monte Carlo方法,求得电子在磁场中的分布,得到电子分布的均值和标准差。本文通过在基片和靶材间加正向电场,改变了电子的运动轨迹和空间分布,优化了矩形平面靶的刻蚀形貌,提高了靶材利用率。     

不同非平衡度磁场环境中溅射等离子体的诊断与分析

采用Langmuir探针对两种不同非平衡度磁场环境中(K值分别为2.78和6.41)的溅射等离子体进行诊断,并使用高斯仪测量靶材表面的磁感应强度,结合靶材表面磁场分布的Ansys软件模拟,分析了等离子体在非平衡磁场环境中的运动规律。结果表明:磁控阴极内侧(靶材表面中部)的溅射等离子体主要参数(离子密度、电子密度及电子温度)在两种不同非平衡度磁场中都具有随靶基距增大而逐渐减小的趋势,大量带电粒子从磁控阴极外端向远离靶材表面的区域运动;K为2.78时的等离子体参数在靶材表面的刻蚀环正上方60 mm范围内明显高于K为6.41时,前者靶材表面的磁感应强度大于后者;向外发散的磁力线数量随K值的增大而增多。     

磁控溅射矩形靶磁场的优化设计

磁控溅射靶材的利用率在降低生产成本中起着重要作用.正交的靶电磁场能显著地延长电子的运动路程,增加同工作气体分子的碰撞几率,提高等离子体密度,使磁控溅射速率数量级的提高,因此靶面正交电磁场的分布将决定靶的烧蚀情况.提出了2种改善矩形平面靶磁场分布的方法,经过分析,这2种设计将拓宽靶面的刻蚀范围,提高靶材的利用率.     

矩形平面磁控溅射装置薄膜沉积仿真

薄膜厚度沿矩形靶长度方向分布的均匀度是衡量矩形平面磁控溅射装置镀膜质量的重要指标。为了分析气压和靶基板间距对该指标的影响,本文采用Monte Carlo方法,在假设靶材沿跑道均匀刻蚀的前提下,对靶材原子沉积过程进行了计算机仿真。模型假设靶材原子出射能量满足Thompson分布,出射角度以余弦定律处理;假设背景气体速度为麦克斯韦分布,并采用舍选法对各个速度分量进行了抽样;应用可变硬球模型对碰撞过程进行了处理。通过仿真发现,随着气压增大,尽管薄膜的均匀度越好,但是靶材原子到达基板的能量会降低;而靶与基板间距越大,薄膜的均匀度和靶材原子到达基板的能量都会降低。另外,通过对矩形靶端部磁场改进,可以削弱靶材的反常刻蚀现象,在提高靶材利用率的同时,可以有效提高薄膜均匀度。     

电弧离子镀的旋转横向磁场弧源设计

电弧离子镀工艺中电弧蒸发产生的大颗粒污染严重影响了所沉积涂层的性能.为了从源头上解决大颗粒难题,本文提出了一种新的旋转横向磁场的设计思路,通过频率和强度可调且覆盖整个靶面的旋转横向磁场控制弧斑的运动.通过有限元模拟磁场的分布,对旋转横向磁场控制的电弧离子镀弧源进行了优化设计.并根据方案制作了旋转磁场发生装置及其电源,使该弧源的旋转磁场具有多模式可调频调幅的功能,用以改善弧斑的放电形式,提高靶材刻蚀均匀性和靶材利用率,减少靶材大颗粒的发射,用以制备高质量的薄膜以及功能薄膜,以拓展电弧离子镀的应用范围.     

第十九讲 真空溅射镀膜

正(接2016年第6期第80页)图70给出了在非平衡四靶闭合磁场结构和四靶镜像磁场结构中,磁控溅射系统的磁场分布情况。比较这两种结构的磁场分布情况,可以看出两者在靶面附近的磁场差别不大,在内外磁极之间以横向磁场为主,通过对电子的紧约束,形成一个电离度很高的等离子体阴极区。区内的正离子对靶面的强烈溅射刻蚀构成了靶材中性粒     

圆柱旋转双面矩形磁控溅射靶磁场的设计计算

本文提出一种新型的圆柱旋转双面矩形磁控溅射靶,它具有平面磁控溅射靶的优点.根据靶的结构与工作原理,给出了圆柱双面矩形磁控靶磁场强度计算数学模型及计算公式.依据该计算方法,对具体的靶进行了计算机编程计算,并根据计算结果绘制出了靶磁场分布曲线.计算结果表明圆柱双面矩形磁控靶的磁场分布比较均匀,磁场强度满足磁控溅射功能的需要,其靶的溅射刻蚀区可宽达40°角的范围.从而提高了膜层的沉积速率及膜层沉积范围,改善了同轴圆柱形磁控靶由于环状磁场所引起的膜层不够均匀及靶材利用率低的问题,可以在靶磁场两侧的大面积平面基片上沉积出膜厚均匀的涂层.     

磁控溅射中旋转阴极的对角效应及其解决途径

对角效应是一种存在于磁控溅射中,由于阳极的不对称分布而引起的一种不对称刻蚀的现象,表现为靠近阳极的一侧溅射跑道沿着霍尔电流方向的转角刻蚀明显增强,而另一侧对应转角刻蚀相对较弱,如为双靶时,表现为沿对角线方向刻蚀增强的现象,导致靶材的不均匀刻蚀及靶材利用率降低.文章研究了这种现象,对其成因进行了分析,并进一步阐明了如何避...     

旋转圆柱靶磁控溅射阴极的磁场模拟及结构设计

基于旋转圆柱靶磁控溅射阴极的工作原理,建立其结构模型,并应用ANSYS有限元方法对旋转靶阴极磁场进行了模拟计算,得到了磁场分量Bx在靶材表面上的二维磁场分布规律。通过调节磁铁的宽和高、磁铁间夹角以及设置可移动磁性挡板等方法优化磁场并设计了一种新型磁场结构旋转靶。本研究为旋转靶磁控溅射阴极的磁场结构设计提供了理论依据。     

外加磁场对磁控溅射靶利用率的影响

通过在基片上直接放置一块永久磁铁来研究外加磁场对磁控溅射靶利用率的影响。实验发现 ,外加磁场的引入改变了靶表面附近的磁场分布 ,因而靶的刻蚀环的位置、宽度和深度均发生了明显的变化 ,靶的利用率在S S构型和S N构型中均比无外加磁场时要高。利用空间模拟磁场成功的解释这一实验现象。在S S构型和S N构型中 ,后者靶的刻蚀深度轮廓线比较平坦 ,相对刻蚀深度值更大 ,更能有效地提高靶的利用率     

圆平面磁控溅射靶磁场的ANSYS模拟分析

磁控溅射靶面磁感应强度的水平分布直接关系到靶材的利用率和刻蚀的均匀性.为了寻求更好的磁控靶结构参数,从而实现靶而水平磁感应强度的均匀分布,作者应用ANSYS软件对SD500型磁控溅射镀膜机的圆平面靶表面磁感应强度进行模拟,应用SHT-V型特斯拉计通过同心十字线法对实物靶表面磁感应强度进行测试,将模拟结果与测量结果进行比较,证明其模拟的准确性.进而对圆平面磁控靶的结构参数进行优化设计,得出靶与磁钢间距为3 mm、磁钢高度为15 mm、内磁柱半径为4 mm、内磁柱高度为14 mm时靶面水平磁感应强度最强、分布最均匀.在工程应用中,设计人员可以预先对靶的参数进行优化设计,使设计的磁控溅射靶更好的满足生产和科学研究的需要.     

射频磁控溅射中离子输运的计算机模拟

采用射频辉光放电等离子体壳层模型和蒙特卡罗法 ,模拟了射频磁控溅射镀膜中工作气体离子 (Ar+)的输运过程 ,得到了离子到达靶面时的入射能量、角度和位置。模拟结果 :对靶材溅射的离子主要来自于溅射坑上方的等离子体区域 ,初始离子的位置分布可通过靶材溅射坑的形貌拟合得到 ;离子的能量主要集中在壳层电压附近 ,离子大多数以垂直入射。模拟与实际相符 ,可用作进一步模拟离子对靶材溅射时的输入参数。     

Some New Views on the Principles of Magnetron Sputtering

In this paper, some common phenomena in magnetron sputtering are freshly analyzed and discussed on the basis of the motion of electrons in non-uniform orthogonal electric and magnetic fields. There exist magnetic confinements in three spatial dimensions on moving charged particles (including electrons) in this kind of non-uniform field. They are the longitudinal cycloidal motion, the horizontal simple harmonic-like motion (with varying amplitudes), and the vertical repelling action. The horizontal magnetic confinement in a mirror-like magnetic field keeps glow discharge lane completely parallel to the corridor of magnetic force lines, therefore only an effectively closed magnet array structure can form a relatively uniform and closed discharge lane. The main reasons for electrons' releasing from magnetic confinement are the vertical magnetic repelling force as well as a more and more weak confinement action in outer range etc. The dominant reasons for a comparatively low increase of substrate's temperature are that the density of bombarding electrons near the substrate is relatively low and their spatial distribution is relatively uniform (compared with that near the target surface). The erosion lane with an inverted Gauss's distribution shape on a magnetron sputtered target is due to that,with sputtering, the distribution width of the critical density of electrons shrinks continuously but the sputtering effect in the centerline of the corridor is always the most powerful.     

磁场非平衡度对CrN_x镀层性能的影响

使用具有不同非平衡度的磁控管直流磁控溅射技术沉积CrN_x镀层,并用Langmuir探针诊断、高斯仪测量、Ansys软件模拟等手段进行表征,研究了磁场非平衡度对溅射等离子体的空间分布状态以及CrN_x镀层的微观结构、硬度及摩擦性能的影响。结果表明:低非平衡度磁控管（K为2.78）将多数离子束缚在靶材表面大约6 cm范围内,而对于高非平衡度磁控管（K为6.41）则在此区域没有类似的高密度等离子体存在。随着磁场非平衡度的增大,CrN_x镀层的厚度递增,物相结构也从Cr+Cr₂N依次向Cr+Cr₂N+CrN和Cr₂N+CrN转化,且镀层的平整度和致密性随之明显改善。同时,CrN_x镀层的硬度随着非平衡度的增大而提高,摩擦系数则随之减小。     

Development of a magnetron sputtering system with an extraordinary strong magnetic field near the target

We have developed a planar sputtering device that uses a melt-processed bulk superconductor to generate the magnetic field. The magnetic field that confines the plasma above the sputtering target is about 1.0 T, which is about 20 times larger than the field normally used for magnetron sputtering. Because of the large magnetic field, discharge at an Ar gas pressure as low as 10⁻³ Pa was possible. In this study, we used the ultra-strong-field sputtering technique for depositing Ga-doped ZnO which is attracting interest as a transparent electrode material. We also studied the effect of employing an auxiliary coil to tailor the magnetic field distribution and discuss how the discharge characteristic had changed.     

"GT target", A new high rate sputtering target of magnetic materials

A new type of a magnetic material target for high rate sputtering, "Gap Type target (GT target)" have been developed. GT target have many narrow gaps crossing the magnetic flux produced by permanent magnets attached to the cathode. Therefore, the magnetic flux being necessary for magnetron sputtering leaks out over the target surface without magnetic saturation of target materials. By using the GT target, the high rate sputtering of magnetic materials is possible even with common permanent magnets. For example, with a Fe target of 20 mm thick, the deposition rate of 1.5 μm/min. with 15 W/cm²power density is obtained by DC magnetron sputtering at argon pressure of10^{-2} sim 1.0pa.     

Friction and adhesion properties of fluorocarbon polymer thin films prepared by magnetron sputtering

Fluorocarbon polymer thin films were deposited onto a SUS302 substrate with a poly(tetrafluoroethylene) (PTFE) target by three different types of r.f. magnetron sputtering systems with strong, weak and unbalanced magnetic fields. Friction and adhesion properties of these polymer thin films were evaluated.Friction coefficient of polymer thin films prepared with strong magnetic field, unbalanced magnetron and without magnetron (r.f. sputtering) was almost the same level, however, that prepared with the weak magnetic field was slightly lower than those of other thin films. Wear durability of polymer thin film increased with increase of the magnetic field.Adhesion strength between these thin films and SUS302 substrate and shear stress were measured by SAICAS. Both of the adhesion strength and shear stress of polymer thin films prepared with r.f. sputtering (without magnetron) were slightly higher than those prepared by magnetron sputtering systems.     

Wide erosion nickel magnetron sputtering using an eccentrically rotating center magnet

A wide erosion magnetron sputtering system for nickel targets has been developed using a large, tall and eccentrically rotating center magnet. In this system, a water cooling unit was attached behind the target except the moving center magnet area. Therefore, the rotating mechanism of yoke magnet could be separated from the cooling water without decreasing the magnetic flux on the target surface and ensure a high reliability of long life use.Utilization on the 5-inches Ni target was 40%, as compared with 12% utilization of the conventional system. The sputtering rate and erosion depth linearly changed while the target was in use, because the increase of magnetic flux was lower than that of a conventional system. Hence, the target life will be precisely managed by the total sputtering time.