Microstructure in electrodeposited copper layers, the role of the substrate

• The microstructures of Cu layers, ranging in thickness from 3 to 12 µm, were investigated. The layers were electrodeposited from an acidic copper electrolyte onto two distinct substrate materials important for the micro-components industry: an Au layer with a pronounced <111>-texture, and a nano-crystalline Ni-P layer. The evolutions of surface topography, morphology and crystallographic texture in the layers were investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis, respectively. Distinct surface topographies were observed for Cu layers deposited on the Au and Ni-P substrates. Deposition onto the Au substrate resulted in a very smooth surface of all Cu layers, whereas the Ni-P substrate caused an irregular surface for 3-µm-thick layers of Cu. The crystallographic texture in the Cu layers in the first few micrometres depended strongly on the crystallographic texture in the substrate. The Cu crystallites inherited the <111>-orientation of the Au substrate, whilst no preferred crystallographic orientation was observed in the Cu crystallites on the nano-crystalline Ni-P substrate. For Cu layers thicker than 3 µm a <110>-fibre texture developed on both the substrates. © 2001 Elsevier Science Ltd. All rights reserved.

Keyword

Copper plating

Electrodeposition

Microstructures

Textures

NATURAL SCIENCES

NATURVETENSKAP

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ref (subject category)

art (subject category)