An integrated solenoid type double-layer magnetic film inductor and its preparation method

Abstract

The invention belongs to the field of integrated circuit technology and provides an integrated solenoid type double-layer magnetic film inductor and a preparation method thereof, which are used to further increase the inductance density and reduce substrate loss. The invention comprises a silicon substrate, a lower magnetic core film, a deep buried layer, a lower coil, an insulating layer, an upper magnetic core film, an insulating layer and an upper coil; the lower magnetic core film is arranged on the silicon substrate, and the deep buried layer covers the silicon On the substrate and bury the lower magnetic core film deeply, the upper surface of the deep buried layer is also provided with a lower coil groove, and the lower coil is correspondingly arranged in the lower coil groove; the upper magnetic core film is located on the deep buried layer, and the upper coil is located On the upper magnetic core film, an insulating layer is set between the lower coil and the upper magnetic core film, and between the upper coil and the upper magnetic core film to isolate each other, and the upper coil and the lower coil are conducted through through holes; the present invention adopts a double-layer magnetic The core film structure increases the inductance value density, reduces the parasitic capacitance loss between the coils, and has a simple preparation process and low preparation cost, which is beneficial to industrial production.

Description

technical field [0001] The invention belongs to the field of integrated circuit technology, and in particular relates to an integrated solenoid type double-layer magnetic film inductor and a preparation method thereof, which are used to improve the inductance density and quality factor. Background technique [0002] Inductor is one of the three major passive devices (inductance, resistance, capacitance), which plays an important role in RFIC circuits, but its integration level has become a bottleneck restricting the integration of RFIC. At present, many famous companies and scientific research institutions in the world, such as Intel, IBM, Tyndall National Laboratory in Ireland, Ferric Corporation in the United States, Stanford University, etc., have introduced the magnetic core film into the inductor to increase the inductance density. The high frequency performance of the magnetic core is directly determines the performance of the inductor. [0003] Judging from the curre...

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Problems solved by technology

The defects in this structure are as follows: first, the lower layer coil is too close to the silicon substrate, and due to the high dielectric loss of semiconductor silicon, parasitic capacitance is formed in the high frequency band, resulting in a large substrate loss; second, in the preparation process , the polishing process is too close to the surface of the lower coil, which is very easy to cause damage to the lower coil; third, the structure uses a single-layer magnetic core film, and the increase in inductance density is still limited

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