Integrated electronic device and method of making the same
An integrated electronic device includes a substrate, passive components, pads for external connection, and three-dimensional wiring. The passive components includes a multi-stage coil inductor provided on the substrate. The multi-stage coil inductor has a plurality of coils disposed in several layers. Mutually adjacent coil wires are spaced-apart from each other. The three-dimensional wiring includes a first wiring portion which extends on the substrate, a second wiring portion which extends off the substrate but along the substrate, and a third wiring portion connecting with the first wiring portion and the second wiring portion.
1. A method of making an integrated electronic device, the method comprising the steps of:
forming a lower conductive portion by electroplating;
forming a first resist pattern having an opening for formation of an upper conductive portion on the lower conductive portion, the opening allowing part of the lower conductive portion to expose;
forming a seed layer over a surface of the first resist pattern and a surface of the lower conductive portion exposed in the opening;
forming a second resist pattern on the first resist pattern, the second resist pattern being formed with an opening;
forming the upper conductor portion by electroplating in the opening of the second resist pattern;
removing the second resist pattern;
removing the seed layer; and
removing the first resist pattern.
2. The method according to claim 1 , wherein the opening of the second pattern is formed above a region in which the lower conductive portion is exposed from the opening of the first resist pattern and a part of the first resist pattern.
3. The method according to claim 1 , wherein:
the lower conductive portion includes a first coil;
the upper conductive portion includes a second coil; and
removing the first resist pattern includes spacing the first coil and the second coil apart from each other by a gap in a direction in which the first coil and the second coil are staked.
4. The method according to claim 3 , wherein:
the lower conductive portion includes the first coil, at least a part of an external connection and a part of three-dimensional wiring; and
the upper conductive portion includes the second coil and an other part of the three-dimensional wiring.