等离子体增强原子层沉积技术制备铜薄膜

Growth of Copper Thin Films by Plasma Enhanced Atomic Layer Deposition

集成电路的高速发展为铜互连提出诸多要求,其中,如何低温条件(≤150℃)下在大深宽比的通孔或沟槽中沉积保形性好、纯度高、导电性好的铜籽晶层是亟需解决的问题。本文利用等离子体增强原子层沉积技术,以脒基铜为铜前驱体,以氢等离子体为还原物质,在较低的沉积温度(100℃)下,沉积了纯度高、导电性能优良的铜薄膜。在10∶1的硅基沟槽中,表面与沟槽底部厚度均匀(~80 nm)。考察了放电输入功率对薄膜形貌的影响并利用时间分辨发射光谱技术对氢等离子体进行在线诊断。本论文研究表明铜脒基前驱体用于低温等离子体辅助原子层沉积工艺,可有效地解决铜薄膜沉积过程中铜粒子的团聚问题,并为其它类脒基前驱体进行金属薄膜的沉积提供借鉴。

The copper films were synthesized inside the trenches with high aspect ratios at 100 （ C by plasma enhanced atomic layer deposition（PEADL） with copper amidinate and H2-plasma as the precursors and reductant, respectively. The impact of the input power on the microstructures was investigated with X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and time-resolved optical emis- sion spectroscopy. The results show that the highly conformal and uniform Cu-coatings, 80 nm in thickness, were synthesized throughout the entire trench with an aspect ratio as high as 10： 1. Besides, as the input power increased, the copper grain size increased, resulting in improvement of crystallinity, possibly because of increasing growth tem- perature. No agglomeration of copper particles was observed. We suggest that the metal amidinate precursors, other than that of Cu, may be of some technological interest in growth of ALD metal films.