Johnson L F, Ingersoll K A
Appl Opt. 1981 Sep 1;20(17):2951-61. doi: 10.1364/AO.20.002951.
A simple phenomenological model has been developed to account for the effects of redeposition during transverse ion-beam erosion of grating relief patterns on surfaces. The model predicts the evolution with time of an inclined facet in the substrate, and the dependence of the facet angle theta(r) on angle of incidence of the ion beam, erosion rates of mask and substrate, and the geometrical parameters of the mask. The results are illustrated by calculation of the angular dependence of theta(r) for AZ-1350 photoresist masks on GaAs and SiO(2) substrates and for Ti on SiO(2). A strong dependence of theta(r) on mask intercept angle alpha is found, except for a limited range in angle of incidence of the ion beam. Combined with results derived previously, the facet angles theta(S) and theta(r) and the groove angle theta(g) of the asymmetric triangular groove profiles produced in these systems have been determined. A groove angle of 90 degrees cannot be obtained for AZ-1350 on GaAs and SiO(2), but in appropriate conditions a 90 degrees groove angle may be obtained in SiO(2) with a Ti mask.
已开发出一个简单的唯象模型，以解释表面光栅浮雕图案在横向离子束刻蚀过程中再沉积的影响。该模型预测了衬底中倾斜小面随时间的演变，以及小面角θ(r)与离子束入射角、掩膜和衬底的刻蚀速率以及掩膜几何参数的关系。通过计算AZ - 1350光刻胶掩膜在GaAs和SiO₂衬底上以及Ti在SiO₂上的θ(r)的角度依赖性来说明结果。发现θ(r)强烈依赖于掩膜截角α，但离子束入射角存在有限范围除外。结合先前得到的结果，已确定了这些系统中产生的不对称三角形沟槽轮廓的小面角θ(S)和θ(r)以及沟槽角θ(g)。对于AZ - 1350在GaAs和SiO₂上，无法获得90度的沟槽角，但在适当条件下，使用Ti掩膜在SiO₂中可能获得90度的沟槽角。
