Miniature inductor for integrated circuits and devices

• US 5,070,317 A
• Filed: 01/17/1989
• Issued: 12/03/1991
• Est. Priority Date: 01/17/1989
• Status: Expired due to Fees

• Current Assignee: Jayant K. Bhagat
• Original Assignee: Jayant K. Bhagat
• Inventors: Bhagat, Jayant K.
• Primary Examiner(s): Skudy, R.
• Assistant Examiner(s): Vyas, Nilay H.
• Application Number:
  US07/298,158
• Time in Patent Office: 1,050 Days
• Field of Search: 336/200, 357/51 L, 357/84, 357/65, 357/51
• US Class Current: 336/200
• CPC Class Codes: B81B 7/0077 Other packages not provided for in groups B81B7/0035 - B81B7/0074
• CPC Class Codes: B81C 1/00214 Processes for the simultaneaous manufacturing of a network or an array of similar microstructural devices
• CPC Class Codes: H01F 17/0033 with the coil helically wound around a magnetic core
• CPC Class Codes: H01F 2017/0086 on semiconductor substrate
• CPC Class Codes: H01H 2001/0057 the contact materials containing refractory materials, e.g. tungsten
• CPC Class Codes: H01H 50/005 using micromechanics
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• CPC Class Codes: H01L 27/08 including only semiconductor components of a single kind
• 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

Spaced apart conductive strips are provided in a first and third of three layers covering a semiconductor substrate. Magnetic core material is included in the second layer so as to be interposed between the conductive strips of the first and second layers. The first and second layers are joined at suitable points so that their respective conductive strips combine to form a helical electrical path which spirals about a core portion of the magnetic material in the second layer. The second layer can be patterned to define a toroidal magnetic path and/or to define a path including a magnetic gap. The armature of an electromechanical relay can be formed within the optional gap by depositing magnetic armature material to partially overlap a sacrificial support base. When the sacrificial support base is etched away, it leaves the overlying armature material free to move.

Claims

1. An electromagnetic device comprising:

a semiconductor substrate having one or more electrical circuits integrally defined therein;

a magnetic shield layer disposed over the substrate,

a first layer of spaced apart conductive strips disposed over the shield layer;

a magnetic core layer superimposed on the first layer of conductive strips patterned to define first and second transverse magnetic paths;

a second layer of spaced apart conductive strips superimposed on the magnetic core layer;

portions of the conductive strips of the second layer are connected to portions of the conductive strips of the first layer to form first and second, substantially helical electrical paths each spiralling about at least one portion of the magnetic core layer for generating or detecting magnetic flux in said one portion of the magnetic core layer, said portion of the magnetic core layer including at least one of said first and second transverse magnetic paths, wherein said magnetic shield layer shields one or more of said electrical circuits from the flux generated or detected by the first and second helical electrical paths.

2. An electromagnetic device comprising:

a semiconductor substrate having one or more electrical circuits integrally defined therein;

a magnetic shield layer disposed over the substrate,

a first layer of spaced apart conductive strips disposed over the shield layer;

a magnetic core layer superimposed of the first layer of conductive strips;

a second layer of spaced apart conductive strips superimposed on the magnetic core layer, portions of the conductive strips of the second layer connected to portions of the conductive strips of the first layer to form a first substantially helical electrical path which spirals about at least one portion of the magnetic core layer for generating or detecting magnetic flux in said one portion of the core layer, and wherein said magnetic shield layer shields one or more of said electrical circuits from the flux generated or detected by the first helical electrical path; and

a movable member which is moved by a force induced by the magnetic flux of the magnetic core layer.

3. The electromagnet of claim 2 wherein the movable bar is resiliently anchored to the substrate.

4. An electromagnetic device comprising:

a semiconductor substrate having one or more electrical circuits integrally defined therein;

a magnetic shield layer disposed over the substrate,

a first layer of spaced apart conductive strips disposed over the shield layer;

a magnetic core layer superimposed on the first layer of conductive strips;

a second layer of spaced apart conductive strips superimposed on the magnetic core layer, portions of the conductive strips of the second layer connected to portions of the conductive strips of the first layer to form a first, substantially helical electrical path which spirals about at least one portion of the magnetic core layer for generating or detecting magnetic flux in said one portion of the core layer, wherein said magnetic shield layer shields one or more of said electrical circuits from the flux generated or detected by the first helical electrical path and wherein the one or more electrical circuits of the semiconductor substrate include a plurality of transistors, the helical electrical path has three connection terminals, and at least two of the transistors are electrically coupled to a corresponding two of the connection terminals.

5. An electromagnetic device comprising:

a semiconductor substrate having one or more electrical circuits integrally defined therein;

a magnetic shield layer disposed over the substrate,

a first layer of spaced apart conductive strips disposed over the shield layer;

a magnetic core layer superimposed on the first layer of conductive strips;

a second layer of spaced apart conductive strips superimposed on the magnetic core layer, portions of the conductive strips of the second layer connected to portions of the conductive strips of the first layer to form a first, substantially helical electrical path which spirals about at least one portion of the magnetic core layer for generating or detecting magnetic flux in said one portion of the core layer, wherein said magnetic shield layer shields one or more of said electrical circuits from the flux generated or detected by the first helical electrical path,

wherein the magnetic core layer includes a substantially annular section having two or more helical electrical paths spiraling there about, said two or more helical electrical paths being electrically isolated from one another, and wherein;

the number of electrical circuit integrally defined in the semiconductor substrate is more than one;

the semiconductor substrate includes substrate isolation means for subdividing the plural electrical circuits of the semiconductor substrate into at least first and second electrically isolated circuit portions and

the substantially annular section of the magnetic core layer is positioned to define a magnetic coupling path extending across the substrate isolation means to magnetically couple the first circuit portion to the second circuit portion.

6. A method for forming an integrated electromagnetic device comprising:

forming a layer of polyimide on or above the semiconductor substrate;

patterning the polyimide layer to define vias extending though the polyimide layer;

depositing a metal film on the patterned polyimide layer such that a portion of the deposited metal film adheres to the bottoms of the vias; and

removing portions of the metal film which have not adhered to the bottoms of the vias;

providing a semiconductor substrate having an integrated circuit integrally defined therein;

providing a bonding layer;

forming a first winding layer on the bonding layer of spaced apart, electrically conductive strips on the substrate, the first winding layer being composed of a first electrically conductive material;

forming a magnetic core above the first layer of conductive strips, the magnetic core being shaped so as to permit the formation of a helical electrical path thereabout where the helical electrical path is to include the conductive strips of the first layer;

forming a second winding layer of spaced apart, electrically conductive strips above the magnetic core, the second winding layer being composed of a second electrically conductive material; and

connecting the conductive strips of the first and second winding layers so as to define a substantially helical electrical path spiraling about the magnetic core;

wherein the forming of the first and second winding layers includes electroplating at least some of at least one of the first and second electrically conductive materials which form the respective conductive strips of the first and second winding layers.