Symmetric differential inductor structure

Abstract

A symmetric differential inductor structure includes first, second, third and fourth spiral conductive wirings disposed in four quadrants of a substrate, respectively. Further, a fifth conductive wiring connects the first and fourth spiral conductive wirings, and a sixth conductive wiring connects the second and third spiral conductive wirings. The first and second spiral conductive wirings are symmetric but not intersected with one another, and the third and fourth spiral conductive wirings are symmetric but not intersected with one another. Therefore, the invention attains full geometric symmetry to avoid using conductive wirings that occupy a large area of the substrate as in the prior art and to thereby increase the product profit and yield.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to inductor structures, and, more particularly, to a symmetric differential inductor structure.[0003]2. Description of Related Art[0004]In the field of semiconductor fabrication processes, differential inductors are important passive components. Generally, there are two types of differential inductors: symmetric differential inductors and center-tap differential inductors.[0005]FIG. 1A shows a symmetric differential inductor 1. Referring to FIG. 1A, the symmetric differential inductor 1 has a T-shaped central conductive wiring 10 disposed in the center of a substrate, a first conductive wiring 11 extending from the left side of the central conductive wiring 10 in a counterclockwise spiral (moving outwards from the center), and a second conductive wiring 12 extending from the right side of the central conductive wiring 10 in a clockwise spiral. One end of the first conductive wiring 11 has a...

AI Technical Summary

Benefits of technology

[0010]According to the present invention, the first and second spiral conductive wirings are symmetric but not intersected with one another, and the third and fourth spiral conductive wirings are symmetric but not intersected with one another, thus attaining full geometric symmetry to avoid using central conductive wirings that occupy a large area of the substrate as in the prior art and to thereby increase the product profit and yield.

Problems solved by technology

However, the T-shaped central conductive wiring 10 of the symmetric differential inductor 1 and the central conductive wiring 20 of the center-tap differential inductor 2 occupy a large area of the substrate, thereby decreasing the product profit.

Further, it is not possible to attain a fully symmetric structure due to the intersections of the spiral conductive wirings in the center-tap differential inductor 2.

As such, phase differences or other interference could occur and adversely affect the product yield and even seriously affect the inductance values and quality factors of the inductor.

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