Integrated circuit with inductance comprises spiral channel in which metal deposit forms inductance winding

摘要

The monolithic circuit includes a substrate (11) on which an inductance is formed. This is achieved by depositing a conducting material on one wall of a spiral channel. The channel may be filled with insulating material. The monolithic circuit includes a substrate (11) on which an inductance is formed. On one surface of the substrate a channel (21) is formed, and this may be in the form of a spiral, extending between a central hole and an outer hole defining the outer end of the spiral. This channel may be formed by laser action. The surface of the channel and that of the end hole is then insulated. Insulation may be achieved in the process by thermal oxidation, whilst the channel itself may alternatively be cut by plasma etching. A conducting material is deposited on at least one wall of the channel, defining a conductive path between the two extreme holes. This conductive spiral forms the inductance. The channel may finally be filled with a further quantity of insulating material.