Integrated circuit toroidal inductor

• US 5,793,272 A
• Filed: 08/23/1996
• Issued: 08/11/1998
• Est. Priority Date: 08/23/1996
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jahnes, Christopher Vincent, Edelstein, Daniel Charles, Uzoh, Cyprian Emeka, Burghartz, Joachim Norbert
• Primary Examiner(s): Gellner, Michael L.
• Assistant Examiner(s): MAI, ANH T
• Application Number:
  US08/701,922
• Time in Patent Office: 718 Days
• Field of Search: 336/200, 336/219, 336/223, 336/222, 336/177, 336/229
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 17/06 with core substantially closed in itself, e.g. toroid
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 27/2895 Windings disposed upon ring cores
• CPC Class Codes: H01F 30/16 Toroidal transformers
• CPC Class Codes: H01F 41/042 by thin film techniques
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

High quality factor (Q) spiral and toroidal inductor and transformer are disclosed that are compatible with silicon very large scale integration (VLSI) processing, consume a small IC area, and operate at high frequencies. The spiral inductor has a spiral metal coil deposited in a trench formed in at dielectric layer over a substrate. The metal coil is enclosed in ferromagnetic liner and cap layers, and is connected to an underpass contact through a metal filled via in the dielectric layer. The spiral inductor also includes ferromagnetic cores lines surrounded by the metal spiral coil. A spiral transformer is formed by vertically stacking two spiral inductors, or placing them side-by-side over a ferromagnetic bridge formed below the metal coils and cores lines. The toroidal inductor includes a toroidal metal coil with a core having ferromagnetic strips. The toroidal metal coil is segmented into two coils each having a pair of ports to form a toroidal transformer.

Claims

1. An integrated circuit toroidal inductor comprising:

a dielectric layer formed over a substrate, and a toroidal metal coil formed in said dielectric layer, said toroidal metal coil having upper and lower metal segments, each upper metal segment having a planar metal portion and a metal stud portion extending downward from said planar metal portion towards said lower segment, said metal stud portion connecting opposing ends of said lower metal segments and said planar metal portions, said integated circuit toroidal inductor further having ferromagnetic strips formed in a core defined by an inner surface of said toroidal metal coil, said ferromagnetic strips being separated from each other and from said inner surface by said dielectric layer.

2. The integrated circuit toroidal inductor of claim 1, wherein inner and outer surfaces of said toroidal metal coil are lined with a ferromagnetic material.

3. The integrated circuit toroidal inductor of claim 1, further comprising a ferromagnetic material formed in a core defined by an inner surface of said toroidal metal coil.

4. The integrated circuit toroidal inductor of claim 1, wherein said toroidal metal coil is segmented into two toroidal coils each having a pair of ports to form a toroidal transformer.