Intrinsic and Passivation‐Induced Trench Tapering during Plasma Etching
Intrinsic and Passivation‐Induced Trench Tapering during Plasma Etching
复制标题
等离子蚀刻过程中固有的和钝化引起的沟槽锥化
DOI：
10.1149/1.2055036
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发表时间：
1994
影响因子：
3.9
通讯作者：
M. Dalvie
中科院分区：
文献类型：
--
作者：
S. Hamaguchi;M. Dalvie
在等离子体刻蚀过程中，经常会观察到侧壁的锥化现象。本文基于数值模拟和表面演化理论，讨论了本征锥化和钝化诱导锥化两种沟槽锥化现象。当刻蚀速率C(0)随着斜率e接近垂直表面的刻蚀速率(即@=_+~r/2)而迅速减小时，发生本征锥化。当粘着系数5e较小时，这是锥形侧壁形成的主要机制。对于较大的粘着系数，钝化诱导的锥化变得更占优势。在等离子体刻蚀中，需要适当控制侧壁锥角，以获得高方向性(即各向异性)刻蚀轮廓。本文基于文献[1]中发展的数值方法，对沟槽锥化过程进行了数值模拟。特别给出了刻蚀沟槽轮廓与刻蚀速率C、粘着概率b和再发射分布等重要系统参数之间的定量关系。如参考文献[1]中所述。2、即使没有在沟槽侧壁上沉积钝化膜，也会发生沟槽锥化。这种类型的锥化程度可以被称为本征锥化，可以根据刻蚀速率C(O)的函数形式来评估，其中O表示倾斜角(见图3)。i)。与参考文献相同。I，2，刻蚀速率C定义为运动表面的法向速度，水平表面(其中0=0)定义为来自等离子体的单向离子束垂直的表面。总的来说，不同材料的刻蚀速率函数C(O)有一些共同的特点。例如，当倾斜角O接近垂直墙的倾斜角时，C(O)减小到0(即O=+~r/2)。特别地，对于~r/2~i@1-<；~r，C(O)=0，因为具有~r/2-<；i@L的斜率不直接暴露在入射光束中。也是最大的
Sidewall tapering is often observed during plasma trench etching. In this paper, two types of trench tapering, intrinsic tapering and passivation-indueed tapering, are discussed based on numerical simulations and theory of surface evolution. Intrinsic tapering occurs when the etch rate C (0) decreases rapidly as the slope angle e approaches that of the vertical surface (ie,@= _+~ r/2). It is the dominant mechanism for the formation of tapered sidewalls when the sticking coefficient 5e is small. For a larger sticking coefficient, passivation-indueed tapering becomes more dominant. Quantitative relations between etched trench profiles and some system parameters such as sticking coefficients, etch rates, and re-emission distributions are also presented.In plasma etching, appropriate control over sidewall taper angles is desired to achieve highly directional (ie, anisotropie) etched profiles. In this paper, we present numerical simulations of trench tapering, based on the numerical methods developed in Ref. i and 2. In particular we present quantitative relations between etched trench profiles and some important system parameters such as etch rate C, sticking probability b, and re-emission distributions. As discussed in Ref. 2, trench tapering occurs even without the deposition of passivation films on the trench sidewalls. The extent of this type of tapering, which may be called intrinsic tapering, may be evaluated from the functional form of the etch rate C (O), where O denotes the slope angle (see Fig. i). As in Ref. i, 2, the etch rate C is defined as the normal velocity of the moving surface and the" horizontal" surface (where 0= 0) is defined as the surface to which the monodireetional ion beam from the plasma is perpendicular. In general, the etch rate functions C (O) for various materials have some common features. For example, C (O) decreases to 0 as the slope angle O approaches that of the vertical wall (ie, O=+~ r/2). In particular, C (O)= 0 for~ r/2~ I@ 1-<~ r since the slope with~ r/2-< I@ l-<~ are not directly exposed to the incoming beam. Also the maximum