Chemical vapor deposition of copper from CuI hexafluoroacetylacetonate trimethylvinylsilane for ultralarge scale integration applications

Abstract

In this article, the authors report the results of a study aimed at optimizing a manufacturable thermal copper-chemical vapor deposition process, using (tmvs) CuI (hfac) as the source, where tmvs=trimethylvinylsilane and hfac=hexafluoroacetylacetonate, and establishing associated material and process characteristics and performance. This study employed a two-stage design of experiments approach in conjunction with actual deposition runs on unpatterned silicon (Si) and titanium nitride (TiN) surfaces, as well as SEMATECH patterned TiN structures with feature sizes as small as 0.30 μm with aspect ratio 6:1. All samples were analyzed by Auger electron spectroscopy, Rutherford backscattering, four-point resistivity probe, and cross-section scanning electron microscopy. The results of these analyses showed that precursor concentration, substrate temperature, and in situ predeposition substrate surface plasma treatment play a key role in achieving good conformality and complete filling at high growth rates in aggressive via and trench structures. Based on these findings, an optimum process window was identified and employed to demonstrate complete high growth rate (∼2000 Å/min) filling of 0.3 μm, 6:1 aspect ratio, devices structures with pure copper at as-deposited resistivities of 1.8 μΩ cm.