Permalloy electroplating through photoresist molds

Electrodeposited Ni80Fe20 magnetic films are used in storage devices and are usually used for MEMS. In this paper, we present some fundamental results concerning the influence of electrodeposition conditions on the films characteristics. In the first step, permalloy electrodeposition has been studied on copper evaporated films without resist patterns. The growth rate varies Linearly as function of the current density (typically 120 nm min(-1) for 10 mA cm(-2)). The variation of the alloy composition with deposition parameters is consistent with the so-called anomalous deposition effect, i.e., a preferential deposition of iron. The composition is the same for films with thickness in the range 0.6-20 mu m and the Fe concentration decreases with current density. An alloy Ni80Fe20 with a density close to the bulk value is obtained for a current density of 14.5 mA cm(-2). Characterization of magnetic properties with a vibrating magnetometer shows that good properties can be obtained (coercivity = 0.35 Oe for a thickness of 600 nm). These results are applied to the patterning of permalloy by electrodeposition through photoresist molds. (C) 1999 Elsevier Science S.A. All rights reserved.