Wei Guo and Herbert H Sawin 2009 J. Phys. D: Appl. Phys. 42 194014 doi:10.1088/0022-3727/42/19/194014
Wei Guo and Herbert H Sawin
Show affiliationsPlasma etching of thin films is essential for microelectronics manufacturing. With current feature sizes of 35 nm in production and processes for smaller devices being developed, the sidewall roughness is within the order of magnitude of the gate length of the device, and therefore significantly impacts the devices' performance. In this paper we review the modelling of the surface profile evolution in plasma etching. Both two-dimensional (2D) and three-dimensional (3D) models have been developed using a number of representations and solution algorithms. String algorithms and the method of characteristics use a segmented string which is incrementally advanced. Level-set representations describe the profile evolution as a moving interface in response to a velocity field. Cellular representations in which the area or volume domain is divided into discrete cells have been used with flux and surface kinetics based on Monte Carlo calculations. We discuss our work in the modelling of profile evolution with surface roughening using a 3D cellular Monte Carlo simulation. The formation of perpendicular and parallel ripple formation on planar surfaces as a function of ion bombardment incidence angle and the transformation from perpendicular to parallel as etching progresses has been modelled. The smoothing and/or roughening of resist masks has been demonstrated along with the pattern transfer of roughness into the underlying layers being etched.
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
52.40.Hf Plasma-material interactions; boundary layer effects
Condensed matter: electrical, magnetic and optical
Issue 19 (7 October 2009)
Received 6 April 2009, in final form 8 July 2009
Published 18 September 2009
Wei Guo and Herbert H Sawin 2009 J. Phys. D: Appl. Phys. 42 194014
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