High Q inductor with faraday shield and dielectric well buried in substrate

• US 6,534,843 B2
• Filed: 02/10/2001
• Issued: 03/18/2003
• Est. Priority Date: 02/10/2001
• Status: Expired due to Term

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Rosner, Joanna, Cordes, Steven A., Groves, Robert A., Lund, Jennifer L., Carasso, Melanie L., Acosta, Raul E.
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): FORDE, REMMON R
• Application Number:
  US09/781,014
• Publication Number:
  US 20020109204A1
• Time in Patent Office: 766 Days
• Field of Search: 257/531, 257/534, 257/539, 257/500, 257/338, 257/351, 257/357
• US Class Current: 257/531
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/363 made of electrically conductive material

Abstract

Inductor losses to a semiconducting substrate are eliminated in an IC structure by etching a well into the substrate down to the insulating layer coating the substrate and fabricating a grounded Faraday shield in the shape of elongated segments in the bottom of the well. The well lies directly below the inductor and is optionally filled with cured low-k organic dielectric or air.

Claims

1. An inductor device for an integrated circuit, comprising:

a. a semiconductor substrate;

b. a well in the substrate, the well having a floor;

c. a conductive ground shield disposed planarly on the well floor in parallel, elongated segments which are connected commonly and connected to ground; and

d. a spiral planar inductor disposed above the well and parallel to the ground shield.

2. The device recited in claim 1, wherein the well is slope-walled.

3. The device recited in claim 2, wherein the slope-walled well is filled with a low-k organic dielectric material, or with air.

4. The device recited in claim 3, wherein the low-k organic dielectric material comprises polyimide or SiLK.

5. The device recited in claim 1, wherein the conductive ground shield is comprised of a metal, doped silicon, doped polysilicon or silicide.

6. The device recited in claim 1, wherein the conductive ground shield is separated from the substrate by a passivation/insulation material selected from the group consisting of SiO2, Si3N4 and BPSG.