Inductive filters and methods of fabrication therefor

• US 7,518,248 B2
• Filed: 08/04/2006
• Issued: 04/14/2009
• Est. Priority Date: 12/28/1999
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Figueroa, David G., Li, Yuan-Liang
• Primary Examiner(s): Warren; Matthew E
• Application Number:
  US11/462,611
• Publication Number:
  US 20060267216A1
• Time in Patent Office: 984 Days
• Field of Search: 257/531, 257/691, 257/698, 257/773, 257/774, 716/15
• US Class Current: 257/774
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 41/041 Printed circuit coils apparatus or processes for manufacturing printed circuits in general H05K3/00
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/49822 Multilayer substrates multilayer metallisation on monolayer substrate H01L23/498
• CPC Class Codes: H01L 23/49838 Geometry or layout
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01046 Palladium [Pd]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2924/15312 being a pin array, e.g. PGA
• CPC Class Codes: H05K 1/115 Via connections; Lands around holes or via connections H05K1/112 takes precedence
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/086 for inductive purposes, e.g. printed inductor with ferrite core
• CPC Class Codes: H05K 2201/097 Alternating conductors, e.g. alternating different shaped pads, twisted pairs; Alternating components
• CPC Class Codes: H05K 2201/1006 Non-printed filter
• CPC Class Codes: H05K 2203/0723 Electroplating, e.g. finish plating
• CPC Class Codes: H05K 3/06 the conductive material being removed chemically or electrolytically, e.g. by photo-etch process semi-additive methods H05K3/108
• CPC Class Codes: H05K 3/42 Plated through-holes or plated via connections

Abstract

A series of plated through hole (PTH) vias are interconnected by traces that alternate between a top surface and a bottom surface of a dielectric board. The PTH vias in the series can be positioned to create a collinear inductive filter, a coil-type inductive filter, or a transformer. Multiple, electrically isolated series of interconnected PTH vias can be used as a multi-phase inductive filter in one embodiment. In another embodiment, multiple series of interconnected PTH vias are electrically connected by a linking portion of conductive material, resulting in a low-resistance inductive filter. Ferromagnetic material patterns can be embedded in the dielectric board to enhance the inductive characteristics of the interconnected via structures. In one embodiment, a closed-end pattern is provided with two series of interconnected vias coiling around the pattern, resulting in an embedded transformer structure. A method of producing an interconnected series of PTH vias includes providing a dielectric board having a series of holes. In some embodiments, the board includes an embedded ferromagnetic material pattern. The holes and the top and bottom surface of the dielectric board have a conductive material thereupon. Portions of the conductive material are selectively removed, resulting in the embedded inductive filter and/or transformer structure.

Claims

1. An inductive filter comprising:

a substrate;

a series of plated through hole (PTH) vias formed in the substrate between a first conductive layer and a second conductive layer, wherein the first conductive layer and the second conductive layer are separated by one or more dielectric layers of the substrate;

conductive material traces within the first conductive layer and the second conductive layer that electrically connect the PTH vias, wherein adjacent PTH vias are electrically connected by a trace on either the first conductive layer or the second conductive layer, and wherein the adjacent PTH vias in the series alternate between being electrically connected by a trace on the first conductive layer or electrically connected by a trace on the second conductive layer;

at least one additional series of PTH vias formed in the substrate; and

additional conductive material traces in the first conductive layer and the second conductive layer that electrically connect the PTH vias in each of the at least one additional series, wherein adjacent PTH vias in the at least one additional series alternate between being electrically connected by traces on the first conductive layer or the second conductive layer.

2. The inductive filter as claimed in claim 1, wherein the series of PTH vias forms a coil-like structure.

3. The inductive filter as claimed in claim 2, wherein the substrate includes an embedded ferromagnetic material pattern, and the coil-like structure winds around the embedded ferromagnetic material pattern.

4. The inductive filter as claimed in claim 1, wherein a linking portion of conductive material electrically connects at least one PTH via in each of the first series and the at least one additional series.

5. A computer system positioned on a printed circuit board, the computer system comprising:

a bus;

a memory coupled to the bus; and

an integrated circuit package coupled to the bus, including;

a package having a first series of plated through hole (PTH) vias that provide electrical connections between a top surface of the package and a bottom surface of the package, wherein the PTH vias in the first series are electrically connected by conductive material traces on the top surface and the bottom surface, and wherein adjacent PTH vias in the first series alternate between being electrically connected by a trace on the top surface or electrically connected by a trace on the bottom surface, and

a microprocessor located on the top surface of the package, the microprocessor containing a circuit which is electrically connected to a PTH via of the series of PTH vias.

6. The computer system as claimed in claim 5, wherein the series of PTH vias forms a coil-like structure, the integrated circuit package includes an embedded ferromagnetic material pattern, and the coil-like structure winds around the embedded ferromagnetic material pattern.

7. The computer system as claimed in claim 5, further comprising:

at least one additional series of PTH vias formed in the integrated circuit package; and

additional conductive material traces on the top surface and the bottom surface that electrically connect the PTH vias in each of the at least one additional series, wherein adjacent PTH vias in the at least one additional series alternate between being electrically connected by traces on the top surface or the bottom surface.

8. A computer system positioned on a printed circuit board, the computer system comprising:

a bus;

a memory coupled to the bus; and

an integrated circuit package coupled to the bus, including;

a package having a first series of plated through hole (PTH) vias that provide electrical connections between a first conductive layer of the package and a second conductive layer of the package, wherein the PTH vias in the first series are electrically connected by conductive material traces on the first conductive layer and the second conductive layer, and wherein adjacent PTH vias in the first series alternate between being electrically connected by a trace in the first conductive layer or electrically connected by a trace in the second conductive layer, and

a microprocessor located on a top surface of the package, the microprocessor containing a circuit which is electrically connected to a PTH via of the series of PTH vias.

9. The computer system as claimed in claim 8, wherein the series of PTH vias forms a coil-like structure.

10. The computer system as claimed in claim 9, wherein the integrated circuit package includes an embedded ferromagnetic material pattern, and wherein the coil-like structure winds around the embedded ferromagnetic material pattern.

11. The computer system as claimed in claim 8, further comprising:

at least one additional series of PTH vias formed in the integrated circuit package; and

additional conductive material traces in the first conductive layer and the second conductive layer that electrically connect the PTH vias in each of the at least one additional series, wherein adjacent PTH vias in the at least one additional series alternate between being electrically connected by traces in the first conductive layer or the second conductive layer.

12. The computer system as claimed in claim 11, wherein a linking portion of conductive material electrically connects at least one PTH via in each of the first series and the at least one additional series.

13. A computer system positioned on a printed circuit board, the computer system comprising:

a bus;

a memory coupled to the bus;

an interposer coupled to the bus, including a first series of plated through hole (PTH) vias that provide electrical connections between a top surface of the interposer and a bottom surface of the interposer, wherein the PTH vias in the first series are electrically connected by conductive material traces on the top surface and the bottom surface, and wherein adjacent PTH vias in the first series alternate between being electrically connected by a trace on the top surface or electrically connected by a trace on the bottom surface; and

an integrated circuit package coupled to the interposer, including a package and a microprocessor located on a top surface of the package.

14. The computer system as claimed in claim 13, wherein the series of PTH vias forms a coil-like structure, the interposer comprises an embedded ferromagnetic material pattern, and the coil-like structure winds around the embedded ferromagnetic material pattern.

15. The computer system as claimed in claim 13, further comprising:

at least one additional series of PTH vias formed in the interposer; and

additional conductive material traces on the top surface and the bottom surface that electrically connect the PTH vias in each of the at least one additional series, wherein adjacent PTH vias in the at least one additional series alternate between being electrically connected by traces on the top surface or the bottom surface.