Influence of the gas pressure in a Torr regime capacitively coupled plasma deposition reactor

Abstract

The adjustment of the gas pressure has been shown to improve the deposition rate and uniformity of a plasma process. This led us to investigate the effect of the gas pressure in a 300 mm wafer reactor. We numerically simulated SiH4/He capacitively coupled plasma discharges for the deposition of a hydrogenated amorphous silicon film. The results indicated that an increase in the gas pressure leads to uniform dissipation of the power coupled to the plasma and deposition profiles. By toggling the sidewall condition from grounded to dielectric while varying the gas pressure, we observed a modification of the plasma distributions and deposition profiles. Based thereupon, we concluded that the combination of high pressure with narrow electrode spacing can guarantee more efficient and uniform deposition. Additionally, this result was experimentally validated using the plasma deposition of hydrogenated amorphous carbon from the mixture C3H6/Ar/He. Even though the mixture differed from that we adopted in the simulation, the combination of high pressure with narrow electrode spacing still induced uniform deposition.

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

“…The recent requirement that the deposition unevenness of the film deposited on the wafer be less than 1%-3% has prompted growing interest in solving the technical problems surrounding the implementation of a uniform deposition process [6,7]. Therefore, ensuring the uniformity of the process results makes it necessary to control the spatial distribution of plasma parameters such as the ionization rate, excitation rate, excitation transfer rate, and electron density [8,9].…”

Two-dimensional particle-in-cell simulation of electron heating effect in multiple hollow cathode trenches with curved boundary

“…Capacitively coupled radio-frequency (RF) plasmas are commonly used in the microelectronics industries, such as dry etching, plasma-enhanced chemical vapor deposition, cleaning, and so on [1][2][3], as it is adequate to make a relatively uniform plasma with a simple structure. Since the RF capacitively coupled plasmas (CCPs) have a small gap between two parallel electrodes, the plasma is mainly heated and transported in the direction perpendicular to the electrode.…”

Effect of dilution gas on the distribution characteristics of capacitively coupled plasma by comparing SiH4/He and SiH4/Ar

“…Our focus, as part of the development of process technology, is on lowering the cost of microchip production and improving the process quality [5,6]. Representative factors that could be considered to accomplish these goals include the type of dilution gas, gas pressure, power delivery, and utilization of high frequency [7,8]. The plasma physical/ chemical roles of these factors are analyzed to optimize the process conditions.…”

“…In addition, in the thin film formation process, pressure conditions of 100 Pa or more are frequently used to prevent the increase in intrinsic stress caused by ion bombardment and to increase the deposition rate by increasing the efficiency of the generation of radicals in the gas phase reaction. For example, in our previous study of the deposition of an amorphous silicon layer using the SiH 4 /He mixture, the amount of SiH 4 used was only 1%-2% of the amount of He used, and the pressure exceeded 400 Pa [8,21,22]. Therefore, because of the large proportion of dilution gas in the mixture, the plasma properties of the mixture are inevitably influenced more profoundly by the type of dilution gas.…”

“…In fact, studies on CCP with these two mixtures have been conducted from various perspectives. For example, in our previous research, SiH 4 /He mixture CCP was used to determine the conditions under which an amorphous silicon layer could be uniformly and rapidly deposited, and ways in which to establish these conditions were studied [8,21,22]. The generation of silicon nanoparticles using SiH 4 /Ar CCP was also previously studied [23][24][25][26][27].…”