Multilayer inductor and production method thereof

• US 20020167389A1
• Filed: 05/20/2002
• Published: 11/14/2002
• Est. Priority Date: 08/06/1999
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Kojima, Noriyuki, Uchikoba, Fumio
• Granted Patent: US 6,839,955 B2
• Time in Patent Office: Days
• US Class Current: 336/200
• CPC Class Codes: H01F 27/027 specially adapted for combination of signal type inductors or transformers with electronic circuits, e.g. mounting on printed circuit boards
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.
• CPC Class Codes: Y10T 29/49163 with sintering of base

Abstract

In the multilayer inductor, the substrate thereof is composed of a constituent belonging to spinel ferrite, and is furnished with internal conductors of a main constituent being silver at the interior of the substrate. The internal conductors are drawn outside of the substrate, and the drawn portions are provided with external electrodes. The internal conductors contain manganese and bismuth, and the manganese and bismuth contents at an interface between the internal conductors and the substrate are more than those of other ranges. MnO₂ of 0.02 to 0.1 wt % and Bi₂O₃ of 0.5 to 1.2 wt % are added to a paste of the main constituent being silver to be used to the internal conductors, and the paste is baked together with spinel ferrite material.

Claims

1. A multilayer inductor comprising:

a substrate composed of a constituent belonging to spinel ferrite;

internal conductors of a main constituent being silver at the interior of the substrate, said internal conductors being drawn outside of the substrate; and

external electrodes provided at the drawn portions of said internal conductors;

wherein the internal conductors contain manganese and bismuth, and the manganese and bismuth contents at an interface between the internal conductors and the substrate are more than those of other ranges.

2. A method of making a multilayer inductor comprising steps of:

adding MnO₂ of 0.02 to 0.1 wt % and Bi₂O₃ of 0.5 to 1.2 wt % to a paste of a main constituent being silver to be used to an internal conductors; and

baking said paste together with spinel ferrite material.