Modeling of Charging on Unconventional Surface Morphologies of PMMA Substrates During Ar Plasma Etching

Abstract

The charging on unconventional, rough, surface morphologies of polymeric substrates is investigated. The case study is Ar plasma etching of PMMA surfaces with sinusoidal profiles resembling rough profiles. A modeling framework for the description of charging on plasma ''wetted'' two-dimensional (2d) surface morphologies is developed. It consists of models for the calculation of the ion and electron trajectories, the local surface charge density, the potential induced by the surface charge, and a surface etching model. The latter is devised by combining experimental measurements and calculations by TRIM code. Etching rate calculations with and without charging are performed; it is shown that charging affects the etching rate mainly due to the decrease of the ion energy. Calculations are performed for sinusoidal profiles of different amplitude (roughness); as the amplitude increases, the ion energy decreases and the angle of ion incidence increases contributing competitively to the etching rate.

The influences of the electrode dimension and the dielectric material on the breakdown characteristics of coplanar dielectric barrier discharge in ambient air

“…Another possible factor is the surface charge accumulated on the dielectric surface, which is largely dependent on the types of dielectric material . Li et al reported that the desorption of the trapped electrons on the dielectric surface can provide seed electrons for the diffuse discharge.…”

Multiscale Modeling of Low Pressure Plasma Etching Processes: Linking the Operating Parameters of the Plasma Reactor with Surface Roughness Evolution

“…θ in Equation is the angle of ion incidence (with respect to the normal to the surface). The angle dependence being expressed by f ( θ ), is approximated by a simple polynomial function aiming to approximate the measured or simulated curves of angle dependent etching yield of polymeric substrates: …”

“…The space [0, φ 1 ] defines the angle range that the etching yield is constant and equal to that at normal incidence. The reported values for φ 2 for Ar + sputtering of several polymeric substrates varies from 60° to 80° . a in the same works varies from 0.67 to 0.13 or even lower depending on the ion energy.…”

“…The reported values for w 2 for Ar þ sputtering of several polymeric substrates varies from 608 to 808. [74,77,81,[83][84][85] a in the same works varies from 0.67 to 0.13 or even lower depending on the ion energy. In this work, w 2 is considered equal to 758 [w 2 ¼ (75/90) Â p/2], a is considered equal to 0.3 and w 1 is assumed equal to 208 [w 1 ¼ (20/90) Â p/2].…”

Relationship between edge roughness in mask pattern and charging in plasma etching

“…A recent work of Memos and Kokkoris has recognized that the rough surface of dielectric materials being etched by plasma indeed presents the charging effect. This is because the roughness results in a local imbalance of negative and positive charges accumulated on dielectric surface.…”