Multi-finger inductor with equal metal length

Abstract

The invention discloses a multi-finger inductor with equal metal length. The multi-finger inductor comprises a plurality of turns of metal paths which are spirally wound in parallel, wherein the lengths of all extended metal paths are equal. Since the metal length difference of a plurality of paths which are connected in parallel is reduced, the resistance values of all paths connected in parallel are equivalent, namely the uniformity of current which flows through each path is enhanced. The metal length difference of each finger is reduced, the influence of a proximity effect between two adjacent fingers at a high frequency is reduced, and the quality factor of the inductor at the high frequency is obviously improved without the sacrificing of inductance values. For the inductor with a smaller internal diameter, the quality factor is obviously improved because of the structure.

Description

technical field [0001] The invention relates to the field of microelectronics, in particular to a multi-finger inductor. Background technique [0002] At present, a large number of passive devices are included in integrated circuits, among which on-chip inductors are a very important one, and on-chip inductors are one of the important components of radio frequency CMOS / BiCMOS integrated circuits. In typical wireless products, inductive components have a significant impact on the overall RF performance. Therefore, the design and analysis of these inductive components have also been extensively studied. As the core component of the RF circuit, the inductor can usually affect the overall performance of the entire circuit. At present, on-chip inductors with high quality factors are widely used in RF circuit modules such as voltage-controlled oscillators and low-noise amplifiers. [0003] Due to the existence of the high-frequency skin effect at high frequencies, the tradition...

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Problems solved by technology

[0003] Due to the existence of the high-frequency skin effect at high frequencies, the traditional RF on-chip single-ended inductors concentrate the current near the surface of the metal wire at high frequencies, while the current inside the wire becomes smaller and smaller, reducing the current flow. The effective metal cross-sectional area causes the equivalent resistance of the metal to increase at high frequencies, thereby reducing the quality factor of the inductor at high frequencies

like figure 1 As shown, in the existing multi-finger inductor structure, the metal lengths of the inner and outer rings are inconsistent, and the metal length of the inner ring is smaller than that of the outer ring, so that the equivalent metal resistance of the inner ring is also smaller than that of the outer ring, so that in Due to the influence of the proximity effect at high frequencies, the current distribution of the inner and outer rings is uneven, which affects the quality factor of the inductor

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