Profile simulation of conformality of chemical vapor deposited copper in subquarter-micron trench and via structures

Abstract

Copper profile evolution in ultralarge scale integration via and trench structures was investigated for thermal low pressure, low temperature, chemical vapor deposition (LPCVD) from CuI(tmvs)(hfac). The investigation examined copper profiles in specialized cantilever structures as a function of systematic changes in key processing conditions, namely, substrate temperature, precursor flux, and hydrogen reactant flow. Resulting experimental observations from cross section scanning electron microscopy were incorporated in a fast analytical simulator, using a two-dimensional adsorption/re-emission model, to simulate copper profile evolution. The deposition profiles were simulated using a single rate limiting precursor model. A comparison of simulation results and actual experimental profiles for thermal LPCVD copper showed that species re-emission within the via and trench structures play a critical role in achieving conformal step coverage and complete filling. In additional, precursor flux and substrate temperature were identified as the dominant parameters in the species re-emission process, with the probability for re-emission being inversely proportional to substrate temperature and directly proportional to precursor flux. The results of this study were employed in the development of an optimum LPCVD process window for complete copper filling of aggressive via and trench structures at growth rates above 2000 Å/min and as-deposited resistivity below 2.0 μΩ cm.

Conformality of Plasma-Assisted ALD: Physical Processes and Modeling

“…This can, in part, be explained by the wide range of methods used to determine the probabilities, ranging from ab initio density functional theory calculations 9 to direct beam experiments, 14 but also by variations in experimental and theoretical accuracies. Temperaturedependent values of s have also been reported; for example, an increase in s with temperature was found for Hf͑NEtMe͒ 4 and Ti͑O i Pr͒ 4 precursor adsorption. 15,16 Regarding the reactant step in plasma-assisted ALD, oxygen radicals appear the most reactive, whereas hydrogen radicals have generally the lowest reactivity.…”

“…For example, for chemical vapor deposition, simulations are numerous and have been used to study many aspects of the deposition process including the conformality that can be achieved by various processes. 4,5 For thermal ALD, a number of theoretical studies regarding conformality have been reported in the literature.…”

Growth of germanium sulfide by hot wire chemical vapor deposition for nonvolatile memory applications

“…On the other hand, the reemission depends indirectly on many deposition parameters, such as temperature, precursor partial pressure, reactant gas flow, etc. [18,19]. More conformal filling means more re-emission events occur till the precursor molecule will react with the growing film surface.…”

“…3a) and the most porous films (highest deposition rate) cannot fill the holes at all. Burke et al [18] have shown that re-emission and surface diffusion are responsible for conformal filling of three dimensional structures by copper. Surface diffusion is a temperature related process and it is significant only at higher temperatures.…”

Metalorganic Chemical Vapor Deposition of Copper Using (Hexafluoroacetylacetonate)Cu(I)(3,3-dimethyl-1-butene) with a Liquid Delivery System

“…The enhancement of precursor concentration can be achieved by increasing the precursor partial pressure in the reaction zone by the increase of the precursor flow while keeping all other process parameters fixed. The partial pressure of precursor (P precursor ) is defined as follows: 17,18) …”