Electrically decoupled integrated transformer having at least one grounded electric shield

• US 7,084,728 B2
• Filed: 12/15/2003
• Issued: 08/01/2006
• Est. Priority Date: 12/15/2003
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Hyvönen, Lassi Pentti Olavi
• Primary Examiner(s): Nguyen, Tuyen T
• Application Number:
  US10/736,809
• Publication Number:
  US 20050128038A1
• Time in Patent Office: 960 Days
• Field of Search: 336/83.R, 336/84.C, 336/200, 336/232, 257/531
• US Class Current: 336/84.00C
• CPC Class Codes: H01F 17/0013 with stacked layers
• CPC Class Codes: H01F 2027/348 Preventing eddy currents
• 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
• CPC Class Codes: H01L 23/5225 Shielding layers formed together with wiring layers
• 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: H01L 2924/3011 Impedance

Abstract

An integrated circuit, such as a radio frequency integrated circuit (RFIC), has a first layer bearing first metallization patterned for defining a first inductive coil, a second layer bearing second metallization patterned for defining a second inductive coil that overlies the first inductive coil and that is magnetically coupled to the first inductive coil through a third layer interposed between the first layer and the second layer. The third layer bears third metallization for defining an electric shield or electrostatic shield. The third metallization is patterned into a plurality of structures having shapes intended to minimize eddy currents. The electric shield is connected to further metallization that carries a ground potential. The third layer may further bear other metallization for coupling together at least two components of the integrated circuit. The integrated circuit may be fabricated by a CMOS process, and the first and second coils may be a primary coil and a secondary coil, respectively, of a radio frequency transformer. An additional electric shield may also be included, and in this case one electric shield can be coupled to a ground potential associated with the primary coil, and the second electric shield can be coupled to a ground potential associated with the secondary coil.

Claims

1. An integrated circuit comprising a first layer bearing first metallization patterned for defining a first inductive coil, a second layer bearing second metallization patterned for defining a second inductive coil that overlies the first inductive coil and that is magnetically coupled to the first inductive coil through a third layer interposed between the first layer and the second layer, said third layer bearing third metallization for defining an electric shield, the third metallization being patterned into a plurality of structures having shapes intended to minimize eddy currents and being connected to further metallization that carries a ground potential.

2. An integrated circuit as in claim 1, where said third layer further bears other metallization for coupling together at least two components of said integrated circuit.

3. An integrated circuit as in claim 1, where said electric shield is patterned to form a plurality of ribbon structures, each ribbon having a width that is a function of a frequency of an electrical signal that is applied to said first inductive coil.

4. An integrated circuit as in claim 1, where said electric shield is patterned to form a plurality of ribbon structures, each ribbon being spaced apart from an adjacent ribbon by a distance that is a function of a distance between said first metallization and said second metallization.

5. An integrated circuit as in claim 1, where said electric shield is patterned to form a plurality of ribbon structures, each ribbon having a width that is a function of a frequency of an electrical signal that is applied to said first inductive coil and each ribbon being spaced apart from an adjacent ribbon by a distance that is a function of a distance between said first metallization and said second metallization.

6. An integrated circuit as in claim 1, where said electric shield is patterned to form a plurality of groups of ribbon structures, within each group the ribbon structures being electrically connected together at one point, and each group being electrically connected together at one point for being connected to the further metallization that carries the ground potential.

7. An integrated circuit as in claim 6, where each group of ribbon structures is electrically connected together at a point located at about a center of the patterning of the first and second metallizations.

8. An integrated circuit as in claim 1, further comprising a fourth layer interposed between the first layer and the second layer, said fourth layer bearing fourth metallization for defining a second electric shield, the fourth metallization also being patterned into a plurality of structures having shapes intended to minimize eddy currents and being connected to still further metallization that carries a ground potential.

9. An integrated circuit as in claim 8, where the further metallization that carries the ground potential carries a ground potential associated with said first inductive coil, and where the still further metallization that carries the ground potential carries a ground potential associated with said second inductive coil.

10. An integrated circuit as in claim 1, where the third metal is a non-ferrous metal.

11. A radio frequency integrated circuit (RFIC) comprising a first layer bearing first metallization patterned for defining a primary coil of at least one transformer, a second layer bearing second metallization patterned for defining a secondary coil of the at least one transformer, one of the primary or the secondary coil overlying the other one of the secondary or primary coil and being magnetically coupled thereto through a third layer interposed between the first layer and the second layer, said third layer bearing third metallization for defining an electrostatic shield for the at least one transformer, the third metallization being patterned into a plurality of structures having shapes intended to minimize eddy currents and being connected to further metallization that carries a ground potential, where said third layer further bears other metallization for coupling together at least two components of said RFIC.

12. An RFIC as in claim 11, where said electrostatic shield is patterned to form a plurality of ribbon structures, each ribbon having a width that is a function of the RF frequency of an electrical signal that is applied to said primary coil.

13. An RFIC as in claim 11, where said electrostatic shield is patterned to form a plurality of ribbon structures, each ribbon having a width that is a function of a skin depth in the third metallization of an RE frequency of an electrical signal that is applied to said primary coil.

14. An RFIC as in claim 11, where said electrostatic shield is patterned to form a plurality of ribbon structures, each ribbon being spaced apart from an adjacent ribbon by a distance that is a function of a distance between said first metallization and said second metallization.

15. An RFIC as in claim 11, where said electrostatic shield is patterned to form a plurality of ribbon structures, each ribbon having a width that is a function of the RE frequency of an electrical signal that is applied to said primary coil and each ribbon being spaced apart from an adjacent ribbon by a distance that is a function of a distance between said first metallization and said second metallization.

16. An RFIC as in claim 11, where said electrostatic shield is patterned to form a plurality of ribbon structures, each ribbon having a width that is a function of a skin depth in the third metallization of an RE frequency of an electrical signal that is applied to said primary coil and each ribbon being spaced apart from an adjacent ribbon by a distance that is a function of a distance between said first metallization and said second metallization.

17. An RFIC as in claim 11, where said electrostatic shield is patterned to form a plurality of groups of ribbon structures, within each group the ribbon structures being electrically connected together at one point, and each group being electrically connected together at one point for being connected to the further metallization that carries the ground potential.

18. An RFIC as in claim 17, where each group of ribbon structures is electrically connected together at a point located at about a center of the patterning of the first and second metallizations.

19. An RFIC as in claim 11, further comprising a fourth layer interposed between the first layer and the second layer, said fourth layer bearing fourth metallization for defining a second electrostatic shield, the fourth metallization also being patterned into a plurality of structures having shapes intended to minimize eddy currents and being connected to still further metallization that carries a ground potential.

20. An RFIC as in claim 19, where the further metallization that carries the ground potential carries a ground potential associated with said primary coil, and where the still further metallization that carries the ground potential carries a ground potential associated with said secondary coil.

21. An RFIC as in claim 11, where the third metal is a non-ferrous metal.

22. An RFIC as in claim 11, where the RFIC is constructed using a CMOS process.

23. A radio frequency integrated circuit (RFIC) comprising a first layer bearing first electrically conductive material patterned for defining a primary coil of at least one transformer, a second layer bearing second electrically conductive material patterned for defining a secondary coil of the at least one transformer, one of the primary or the secondary coil overlying the other one of the secondary or primary coil and being magnetically coupled thereto through a third layer interposed between the first layer and the second layer, said third layer bearing third electrically conductive material for defining at least one electric shield for the at least one transformer, the third electrically conductive material being patterned into a plurality of structures having shapes intended to minimize eddy currents and being connected to further electrically conductive material that carries a ground potential.

24. An RFIC as in claim 23, where at least some of said electrically conductive material is comprised of metal.

25. An RFIC as in claim 23, where at least some of said electrically conductive material is comprised of a non-metal.

26. An RFIC as in claim 23, where said transformer is a balanced transformer, and where said at least one electric shield functions to improve the symmetry of the balanced transformer.

27. An RFIC as in claim 23, where said RFIC comprises a plurality of transformers, and where said third layer bears the third electrically conductive material for defining, for each of said plurality of transformers, at least one electric shield.

28. An RFIC as in claim 27, where said third layer further bears other electrically conductive material for coupling together at least two components of said RFIC.