The segmented non-uniform dielectric module design for uniformity control of plasma profile in a capacitively coupled plasma chamber

Abstract

Low-temperature plasma technique is one of the critical techniques in IC manufacturing process, such as etching and thin-film deposition, and the uniformity greatly impacts the process quality, so the design for the plasma uniformity control is very important but difficult. It is hard to finely and flexibly regulate the spatial distribution of the plasma in the chamber via controlling the discharge parameters or modifying the structure in zero-dimensional space, and it just can adjust the overall level of the process factors. In the view of this problem, a segmented non-uniform dielectric module design solution is proposed for the regulation of the plasma profile in a CCP chamber. The solution achieves refined and flexible regulation of the plasma profile in the radial direction via configuring the relative permittivity and the width of each segment. In order to solve this design problem, a novel simulation-based auto-design approach is proposed, which can automatically design the positional sequence with multi independent variables to make the output target profile in the parameterized simulation model approximate the one that users preset. This approach employs an idea of quasi-closed-loop control system, and works in an iterative mode. It starts from initial values of the design variable sequences, and predicts better sequences via the feedback of the profile error between the output target profile and the expected one. It never stops until the profile error is narrowed in the preset tolerance.

Numerical optimization of dielectric properties to achieve process uniformity in capacitively coupled plasma reactors

“…The changes in the spatial distributions of the plasma parameters by using a combination of dielectric components with different dielectric constants to fabricate the component that plays the role of an electrode, such as the showerhead, were previously studied [10][11][12]. However, studies of the effect of using a combination of dielectric parts on the sidewall do not seem to have been reported.…”

“…To address this, Yang and Kushner proposed differential conductivity electrodes using multiple layers of dielectric materials [10]. Xia et al proposed a segmented non-uniform dielectric module design for uniformity control [11]. As an alternative, Michna and Ellingboe proposed the use of a multi-tiled system where adjacent tiles are out of phase to ensure good uniformity [12].…”

New simulation-based approach for the profile control in a process chamber: Fluid, thermal, and plasma profile

“…For the detail of the model and reactions of Ar, it is referred in the literature. 34 The main structural parameters of the numerical model are configured as follows: the thickness of the dielectric module h 1 ¼ 8 mm; and the module is partitioned into N equidistant and ring-like sub-regions along the radial direction; the gap between the showerhead and the pedestal is H ¼ 30 mm. The thickness and relative permittivity of the shell-like quartz outside the pedestal is 5 mm and 4 mm, respectively.…”