US-12628357-B2 - Ferromagnetic plates for enhancing inductance and methods of forming the same

US12628357B2US 12628357 B2US12628357 B2US 12628357B2US-12628357-B2

Abstract

A semiconductor structure includes an inductive metal line located in a dielectric material layer that overlies a semiconductor substrate and laterally encloses a first area; and an array of first ferromagnetic plates including a first ferromagnetic material and overlying or underlying the inductive metal line. For any first point that is selected within volumes of the first ferromagnetic plates, a respective second point exists within a horizontal surface of the inductive metal line such that a line connecting the first point and the second point is vertical or has a respective first taper angle that is less than 20 degrees with respective to a vertical direction. The magnetic field passing through the first ferromagnetic plates is applied generally along a hard direction of magnetization and the hysteresis effect is minimized.

Inventors

Yu-Sheng Chen
Hsien Jung CHEN
Kuen-Yi Chen
Chien Hung Liu
Yi Ching Ong
Yu-Jen Wang
Kuo-Ching Huang
Harry-Hak-Lay Chuang

Assignees

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LIMITED

Dates

Publication Date: 20260512
Application Date: 20220808

Claims (20)

1 . A semiconductor structure comprising: an inductive metal line located in a dielectric material layer that overlies a semiconductor substrate and laterally encloses a first area; an array of first ferromagnetic plates comprising a first ferromagnetic material and overlying or underlying the inductive metal line, wherein, for any first point that is selected within volumes of the first ferromagnetic plates, a respective second point exists within a horizontal surface of the inductive metal line such that a line connecting the first point and the second point is vertical or has a respective first taper angle that is less than 20 degrees with respective to a vertical direction; and an array of nonmagnetic metallic plates in contact with the array of first ferromagnetic plates, wherein an nonmagnetic metallic plate selected from the array of nonmagnetic plates has a substantially same area as a respective overlying or underlying first ferromagnetic plate within the array of first ferromagnetic plates.
2 . The semiconductor structure of claim 1 , wherein the array of first ferromagnetic plates laterally encloses a second area that has a partial overlap with the first area in a plan view, and the second area is free of the first ferromagnetic material and is free of any other ferromagnetic material.
3 . The semiconductor structure of claim 1 , wherein a ferromagnetic plate selected from the array of first ferromagnetic plates has a respective maximum lateral dimension that is greater than twice a vertical dimension of the first ferromagnetic plates.
4 . The semiconductor structure of claim 1 , wherein a first ferromagnetic plate within the array of first ferromagnetic plates has a maximum vertical dimension less than 10 nm.
5 . The semiconductor structure of claim 4 , wherein the first ferromagnetic plate within the array of first ferromagnetic plates has a maximum lateral dimension in a range from 10 nm to 200 nm.
6 . The semiconductor structure of claim 1 , wherein a ratio of an overlap area between the inductive metal line and the array of first ferromagnetic plates in a plan view to a total area of the inductive metal line in the plan view is in a range from 0.10 to 0.90.
7 . The semiconductor structure of claim 1 , further comprising an array of second ferromagnetic plates in contact with the array of nonmagnetic metallic plates and comprising a second ferromagnetic material.
8 . The semiconductor structure of claim 7 , wherein: the array of first ferromagnetic plates overlies the inductive metal line; the semiconductor structure comprises an array of second ferromagnetic plates underlying the inductive metal line; a second ferromagnetic plate selected from the array of second ferromagnetic plates comprises a second ferromagnetic material; and for any third point that is selected within volumes of the second ferromagnetic plates, a respective fourth point exists within another horizontal surface of the inductive metal line such that a line connecting the third point and the fourth point is vertical or has a second taper angle that is less than 20 degrees with respective to the vertical direction.
9 . The semiconductor structure of claim 1 , wherein the inductive metal line comprises multiple loop segments that are interconnected to one another in a spiral configuration.
10 . A semiconductor structure comprising: semiconductor devices located on a semiconductor substrate; metal interconnect structures located within dielectric material layers that overlie the semiconductor devices and electrically connected to the semiconductor devices; an inductive metal line that overlies the metal interconnect structures, electrically connected to a subset of the metal interconnect structures, and laterally enclosing an area; and an array of first ferromagnetic plates overlying the metal interconnect structures, and overlying or underlying the inductive metal line, wherein, for any first point that is selected within volumes of the first ferromagnetic plates, a respective second point exists within a horizontal surface of the inductive metal line such that a line connecting the first point and the second point is vertical or has a respective first taper angle that is less than 20 degrees with respective to a vertical direction; and an array of nonmagnetic metallic plates in contact with the array of first ferromagnetic plates, wherein a nonmagnetic metallic plate selected from the array of nonmagnetic metallic plates has a substantially same area as a respective overlying or underlying first ferromagnetic plate within the array of first ferromagnetic plates.
11 . The semiconductor structure of claim 10 , further comprising an array of second ferromagnetic plates in contact with the array of nonmagnetic metallic plates and comprising a second ferromagnetic material.
12 . The semiconductor structure of claim 10 , wherein: the array of first ferromagnetic plates overlies the inductive metal line; the semiconductor structure comprises an array of second ferromagnetic plates comprising a second ferromagnetic material and underlying the inductive metal line; and for any third point that is selected within volumes of the second ferromagnetic plates, a respective fourth point exists within another horizontal surface of the inductive metal line such that a line connecting the third point and the fourth point is vertical or has a second taper angle that is less than 20 degrees with respective to the vertical direction.
13 . A semiconductor structure comprising: an inductive metal line located in a dielectric material layer that laterally encloses a first area; an array of first ferromagnetic plates each comprising a first ferromagnetic material and having at least partial overlap with the inductive metal line in a plan view; and an array of nonmagnetic metallic plates in contact with the array of first ferromagnetic plates, wherein a nonmagnetic plate selected from the array of nonmagnetic metallic plates has a substantially same area as a respective overlying or underlying first ferromagnetic plate within the array of first ferromagnetic plates.
14 . The semiconductor structure of claim 13 , wherein the array of first ferromagnetic plates laterally encloses a second area that has a partial overlap with the first area in a plan view, and the second area is free of the first ferromagnetic material and is free of any other ferromagnetic material.
15 . The semiconductor structure of claim 13 , further comprising an array of second ferromagnetic plates in contact with the array of nonmagnetic metallic plates and comprising a second ferromagnetic material.
16 . The semiconductor structure of claim 13 , wherein: the array of first ferromagnetic plates overlies the inductive metal line; and the semiconductor structure comprises an additional array of additional ferromagnetic plates that underlie the inductive metal line.
17 . The semiconductor structure of claim 13 , wherein: the array of first ferromagnetic plates and the array of nonmagnetic metallic plates are included in a superlattice structure comprising multiple repetitions of a unit layer stack including a ferromagnetic material layer and a nonmagnetic metallic material layer; and a number of repetitions of the unit layer stack is in a range from 2 to 10, and the ferromagnetic material layer in the superlattice structure has a respective thickness less than 10 nm.
18 . The semiconductor structure of claim 13 , wherein: a first ferromagnetic plate selected from the array of first ferromagnetic plates comprises a ferromagnetic material selected from the group consisting of Fe, Co, Ni, NiFe, CoFe, NiCo, NiCoFe, compound rare earth-containing ferromagnetic materials, and ferromagnetic alloys thereof; and the ferromagnetic material in the first ferromagnetic plate is doped with a dopant element selected from B, C, O, Ta, W, Zr, Pt, Mo, Mn, Ru, Mg, Hf, and Ir.
19 . The semiconductor structure of claim 13 , further comprising an array of second ferromagnetic plates in contact with the array of nonmagnetic metallic plates and comprising a second ferromagnetic material, wherein: a nonmagnetic metallic plate selected from the array of nonmagnetic metallic plates comprises a nonmagnetic transition metal selected from Ta, Mo, W, Hf, Zr, Ru, Pt, and Pd and has a thickness in a range from 10 nm to 30 nm; and the nonmagnetic metallic plate is selected such that magnetization of the first ferromagnetic material in the first ferromagnetic plate is ferromagnetically or antiferromagnetically coupled, through the nonmagnetic metallic plates, to magnetization of the second ferromagnetic material in the second ferromagnetic plates.
20 . The semiconductor structure of claim 15 , wherein a coverage ratio of the second ferromagnetic plates, defined as a ratio of a sum of areas of the second ferromagnetic plates relative to an area of a region including the second ferromagnetic plates in a plan view, is in a range from 0.10 to 0.90.

Description

BACKGROUND Metal lines at interconnect-level dielectric material layers may be used to provide inductor structures in an integrated circuit. Such inductor structures tend to provide a low per-volume inductance, and thus, tend to occupy a significant volume in the integrated circuit. Inductor structures providing a higher per-volume inductance are desired. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIG. 1 is a vertical cross-sectional view of a first exemplary structure after formation of complementary metal-oxide-semiconductor (CMOS) transistors, first metal interconnect structures formed in lower-level dielectric material layers, and an isolation dielectric layer according to an embodiment of the present disclosure. FIG. 2A is a vertical cross-sectional view of the first exemplary structure after formation of under-inductor-level metal interconnect structures according to an embodiment of the present disclosure. FIG. 2B is a top-down view of the first exemplary structure of FIG. 2A. FIG. 3A is a vertical cross-sectional view of the first exemplary structure after formation of an inductive metal line and inductor-level metal interconnect structures according to an embodiment of the present disclosure. FIG. 3B is a top-down view of the first exemplary structure of FIG. 3A. FIG. 4 is a vertical cross-sectional view of the first exemplary structure after formation of a base dielectric material layer and a layer stack containing a first ferromagnetic material layer, a nonmagnetic metallic layer, and a second ferromagnetic material layer according to an embodiment of the present disclosure. FIG. 5A is a vertical cross-sectional view of the first exemplary structure after patterning the layer stack into a stack of an array of first ferromagnetic plates, an array of nonmagnetic metallic plates, and an array of second ferromagnetic plates according to an embodiment of the present disclosure. FIG. 5B is a top-down view of the first exemplary structure of FIG. 5A. FIG. 5C is a top-down view of an alternative configuration of the first exemplary structure of FIG. 5A. FIG. 6 is a vertical cross-sectional view of the first exemplary structure after formation of an over-inductor-level insulating layer according to an embodiment of the present disclosure. FIG. 7 is a vertical cross-sectional view of a first alternative configuration of the first exemplary structure according to an embodiment of the present disclosure. FIG. 8 is a vertical cross-sectional view of a second alternative configuration of the first exemplary structure according to an embodiment of the present disclosure. FIG. 9A is a vertical cross-sectional view of a second exemplary structure after formation of an inductive metal line and inductor-level metal interconnect structures according to an embodiment of the present disclosure. FIG. 9B is a top-down view of the second exemplary structure of FIG. 9A. FIG. 9C is a top-down view of an alternative configuration of the second exemplary structure of FIG. 9A. FIG. 10A is a vertical cross-sectional view of the second exemplary structure after formation of an array of first ferromagnetic plates, an array of nonmagnetic metallic plates, and an array of second ferromagnetic plates according to an embodiment of the present disclosure. FIG. 10B is a top-down view of the second exemplary structure of FIG. 10A. FIG. 10C is a top-down view of an alternative configuration of the second exemplary structure of FIG. 10A. FIG. 11 is a vertical cross-sectional view of the second exemplary structure after formation of an over-inductor-level insulating layer according to an embodiment of the present disclosure. FIG. 12 is a vertical cross-sectional view of a first alternative configuration of the second exemplary structure according to an embodiment of the present disclosure. FIG. 13 is a vertical cross-sectional view of a second alternative configuration of the second exemplary structure according to an embodiment of the present disclosure. FIG. 14A is a vertical cross-sectional view of a third exemplary structure after formation of an array of first lower ferromagnetic plates, an array of lower nonmagnetic metallic plates, and an array of second lower ferromagnetic plates according to an embodiment of the present disclosure. FIG. 14B is a top-down view of the third exemplary structure of FIG. 14A. FIG. 14C is a top-down view of an alternative configuration of the third exemplary structure of FIG. 14A. FIG. 15A is a vertical cross-sectional view of the third exemplary structure after formation of an array of first upper ferromagnetic plates, an array of upper nonmagnetic m