With a measurement technique called television holographic interferometry, we investigated the internal stress generated at the initial deposition stage in electrolessly deposited Cu films on silicon substrates. In a region of film thickness less than 100 nm, two inflection points, at which the direction of stress was reversed, were observed on the film thickness-stress curve. From cross-sectional transmission electron microscopy observation of these films, it was found that the films grew in the Volmer-Weber mode and that the above inflection points related to specific stages observed, such as islands growth, islands coalescence, the formation of continuous film, and grain growth. (c) 2007 The Electrochemical Society.