Multi-turn, multi-level IC inductor with crossovers

• US 5,610,433 A
• Filed: 03/13/1995
• Issued: 03/11/1997
• Est. Priority Date: 03/13/1995
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Issaq, Enayet U., Merrill, Richard B.
• Primary Examiner(s): LARKINS, WILLIAM
• Application Number:
  US08/404,019
• Time in Patent Office: 729 Days
• Field of Search: 257/531, 336/200, 336/232
• US Class Current: 257/531
• CPC Class Codes: H01F 17/0013 with stacked layers

Abstract

A high value inductor with a high Q factor is formed using integrated circuit techniques to have a plurality of layers, where each layer has formed on it two or more coils. The coils in the various layers are interconnected in series. Although the resulting inductor exhibits a relatively high resistance, the number of coil turns is large. Since inductance increases in proportion to the square of the number of coil turns, the resulting inductor has a very high Q factor. A cross-over arrangement located in one level provides compact connections between turns in a different level.

Claims

1. An inductor formed on a substrate using integrated circuit techniques, said inductor comprising:

a first conductive coil and a second conductive coil formed on a first insulating surface, said first conductive coil being substantially formed within the boundaries of said second conductive coil;

a third conductive coil and a forth conductive coil formed on a second insulating surface, said third conductive coil being substantially formed within the boundaries of said fourth conductive coil;

a fifth conductive coil and a sixth conductive coil formed on a third insulating surface, said fifth conductive coil being substantially formed within the boundaries of said sixth conductive coil,

said first conductive coil, said third conductive coil, and said fifth conductive coil being substantially axially aligned, said second conductive coil, said fourth conductive coil, and said sixth conductive coil being substantially axially aligned,

a first end of said first conductive coil being connected to a first end of said third conductive coil, a second end of said third conductive coil being connected to a first end of said fifth conductive coil, a second end of said fifth conductive coil being connected to a first end of said sixth conductive coil, a second end of said sixth conductive coil being connected to a first end of said fourth conductive coil, a second end of said fourth conductive coil being connected to a first end of said second conductive coil,

a second end of said second conductive coil receiving an input current, and a second end of said first conductive coil providing an output current so as to create a series combination of said first conductive coil, said third conductive coil, said fifth conductive coil, said sixth conductive coil, said fourth conductive coil, and second conductive coil,

all connections between conductive coils on different insulating surfaces being made with conductive vias formed through an insulating surface;

a seventh conductive coil formed on said first insulating surface, said first conductive coil and said second conductive coil being substantially formed within the boundaries of said seventh conductive coil;

an eighth conductive coil formed on said second insulting surface, said third conductive coil and said fourth conductive coil being substantially formed within the boundaries of said eighth conductive coil;

a ninth conductive coil formed on said third insulating surface, said fifth conductive coil and said sixth conductive coil being substantially formed within the boundaries of said ninth conductive coil,

said seventh conductive coil, said eighth conductive coil, and said ninth conductive coil being substantially axially aligned,

a first end of said seventh conductive coil being connected to said second end of said second conductive coil, a first end of said eighth conductive coil being connected to a second end of said seventh conductive coil,

a second end of said eighth conductive coil being connected to a first end of said ninth conductive coil, a second end of said ninth conductive coil being connected to receive said input current, said second end of said first conductive coil connected to provide said output current, so as to create a series combination of said first conductive coil, said third conductive coil, said fifth conductive coil, said sixth conductive coil, said fourth conductive coil, said second conductive coil, said seventh conductive coil, said eighth conductive coil, and said ninth conductive coil; and

a conductive bridge formed on said second insulating surface connecting said first end of said seventh conductive coil to said second end of said second conductive coil.

2. The inductor of claim 1 further comprising:

a first conductive lead formed on said second insulating surface connected to said second end of said first conductive coil, said first conductive lead providing said output current; and

a second conductive lead formed on said second insulating surface connected to said second end of said ninth conductive coil, said second conductive lead receiving said input current.

3. The inductor of claim 1 wherein said conductive bridge has a width dimension and a length dimension, said width dimension being substantially the same as a width dimension of said first end of said eighth conductive coil, a length of said conductive bridge running along side a length of said first end of said eighth conductive coil.

4. The inductor of claim 1 wherein said first conductive coil, said second conductive coil, said third conductive coil, said fourth conductive coil, said fifth conductive coil, said sixth conductive coil, said seventh conductive coil, said eighth conductive coil, and said ninth conductive coil are rectangular.