Patent ID: 6716693
Filing Date: 2004-04-06
Classification: H01F,H01L

Abstract:
A method of forming trench and channel, or tunnel, openings for an inductor comprising the following steps:(a) providing an insulating layer overlying a substrate; (b) forming a patterned first silicon nitride sacrificial layer, for subsequent channel formation, over the insulating layer; (c) providing a first dielectric layer, overlying said patterned first silicon nitride sacrificial layer; (d) forming a patterned second silicon nitride sacrificial layer over the first dielectric layer; (e) forming a second dielectric layer, over said patterned second silicon nitride sacrificial layer and planarizing the second dielectric layer, by chemical mechanical polishing; (f) forming via openings in the second dielectric layer, by patterning and selectively removing regions of the second dielectric layer, by a reactive ion etch, stopping on the patterned second silicon nitride sacrificial layer, while exposing portions of the underlying first silicon nitride sacrificial layer; (g) changing plasma etching chemistry to etch through exposed regions of the underlying second silicon nitride sacrificial layer, and while continuing to pattern the first dielectric layer, forming vertical channels of the inductor by reactive ion etching, stopping on the patterned first silicon nitride sacrificial layer; (h) selectively wet etching away the underlying first and second silicon nitride sacrificial layers, thus forming both top and bottom horizontal channels or tunnels.