VARIABLE INDUCTOR AND SEMICONDUCTOR DEVICE USING SAME

• US 20130140672A1
• Filed: 01/26/2012
• Published: 06/06/2013
• Est. Priority Date: 03/29/2011
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Sato, Junji, Mizuno, Koichi, Fujita, Suguru
• Granted Patent: US 9,324,778 B2
• Time in Patent Office: Days
• US Class Current: 257/531
• CPC Class Codes: H01F 2027/2809 on stacked layers
• CPC Class Codes: H01F 21/005 Inductances without magnetic core
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 27/0605 integrated circuits made of compound material, e.g. AIIIBV
• CPC Class Codes: H01L 28/10 Inductors
• 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

Abstract

A variable inductor includes a spiral inductor, a loop conductor, and a switch for opening or short-circuiting an end of the loop conductor. The loop conductor is formed in a direction perpendicular to the spiral inductor and is used for adjusting the inductance value of the spiral inductor by opening or short-circuiting the end of the loop conductor by the switch.

Claims

1. A variable inductor comprising:

a spiral inductor formed on a semiconductor substrate;

a loop conductor; and

a switch adapted to open or short-circuit one end of the loop conductor,

wherein the loop conductor is placed in a layer which is lower than the spiral inductor; and

wherein an inductance value of the spiral inductor is changed by opening or short-circuiting the one end of the loop conductor by use of the switch.

2. The variable inductor according to claim 1, wherein the loop conductor is formed in a vertical direction with respect to the spiral inductor.

3. The variable inductor according to claim 2, wherein the spiral inductor is formed on one surface of the semiconductor substrate;

and

wherein the loop conductor includes;

a first layer conductor formed in a layer which is lower than the spiral inductor;

a second layer conductor formed in a layer which is lower than the first layer conductor;

a vertical conductor formed in a via which is formed in at least a part of the semiconductor substrate in a direction perpendicular to the one surface and which connects the first layer conductor to the second layer conductor; and

the switch adapted to open or short-circuit the one end of the loop conductor.

4. The variable inductor according to claim 3, wherein the semiconductor substrate is a silicon substrate;

wherein the spiral inductor is formed from a surface conductor formed on a topmost layer of the silicon substrate;

wherein the first conductor is an inner layer conductor positioned at a lower layer side with respect to the surface conductor through an interlayer dielectric film;

wherein the second conductor is a backside conductor formed on a back side of the silicon substrate; and

wherein the loop conductor includes;

the inner layer conductor;

the vertical conductor formed in a pass-through via which penetrates through the silicon substrate;

the backside conductor; and

the switch adapted to open or short-circuit the one end of the loop conductor.

5. The variable inductor according to claim 1, wherein the loop conductor is located below or inside a region surrounded by an outermost peripheral line constituting the spiral inductor.

6. The variable inductor according to claim 1, wherein the switch includes a variable resistor connected to the one end of the loop conductor, and controls an inductance value of the spiral inductor by controlling a resistance value of the variable resistor.

7. The variable inductor according to claim 1, wherein a plurality of loop conductors are provided beneath the spiral inductor.

8. The variable inductor according to claim 1, wherein the loop conductor has a spiral shape which is turned a plurality of times in a direction perpendicular to a surface of the semiconductor substrate on which the spiral inductor is formed;

and

wherein the switch opens or short-circuits the one end of the loop conductor to change the number of turns of the loop conductor.

9. A semiconductor device comprising the variable inductor according to claim 1.