3-D inductor and transformer devices in MRAM embedded integrated circuits
View Patent ↗An integrated circuit device includes a magnetic random access memory (“MRAM”) architecture and at least one inductance element formed on the same substrate using the same fabrication process technology. The inductance element, which may be an inductor or a transformer, is formed at the same metal layer (or layers) as the program lines of the MRAM architecture. Any available metal layer in addition to the program line layers can be added to the inductance element to enhance its efficiency. The concurrent fabrication of the MRAM architecture and the inductance element facilitates an efficient and cost effective use of the physical space available over active circuit blocks of the substrate, resulting in three-dimensional integration.
1. A method of forming an integrated circuit device, said method comprising:
forming, on a substrate, at least one digit line from a first metal layer;
forming, on said substrate, at least one bit line from a second metal layer;
forming, on said substrate and between said first metal layer and said second metal layer, a magnetic tunnel junction core, said at least one digit line, said at least one bit line, and said magnetic tunnel junction core comprising a magnetic random access memory (“MRAM”) architecture; and
forming, on said substrate, an inductor from at least one of said first metal layer or said second metal layer, wherein the inductor is formed on a portion of said first metal layer that is physically separated from said at least one digit line or on a portion of said second metal layer that is physically separated from said at least one bit line.
2. A method according to claim 1 , wherein forming said inductor comprises forming a spiral inductor from at least one of said first metal layer, concurrently with said at least one digit line, or said second metal layer, concurrently with said at least one bit line.
3. A method according to claim 1 , further comprising forming a magnetic shield layer over said inductor.
4. A method according to claim 1 , wherein forming said inductor comprises:
forming the inductor as a coil section within an area of said first metal layer or said second metal layer that that does not intersect areas of said first metal layer or said second metal layer within which said at least one digit line or said at least one bit line are formed.
5. A method according to claim 1 , wherein forming said inductor comprises:
forming said inductor as a coil section having an area within which no other electrical components are located.
6. A method of forming an integrated circuit device, said method comprising:
forming, on a substrate, at least one digit line from a first metal layer;
forming, on said substrate, at least one bit line from a second metal layer;
forming, on said substrate and between said first metal layer and said second metal layer, a magnetic tunnel junction core, said at least one digit line, said at least one bit line, and said magnetic tunnel junction core comprising a magnetic random access memory (“MRAM”) architecture; and
forming, on said substrate, a transformer from said first metal layer or said second metal layer by
forming a first spiral element from said first metal layer concurrently with said at least one digit line,
forming a second spiral element from said second metal layer concurrently with said at least one bit line, and
forming a number of conductive vias between said first spiral element and said second spiral element, wherein the transformer is formed on portions of said first metal layer and portions of said second metal layer that are physically separated from said at least one digit line and from said at least one bit line.
7. A method according to claim 6 , wherein forming said transformer comprises:
forming a first spiral element from said first metal layer concurrently with said at least one digit line;
forming a second spiral element from said second metal layer concurrently with said at least one bit line;
forming at least one additional spiral element from at least one additional metal layer other than said first metal layer and said second metal layer; and
forming a number of conductive vias between said first spiral element, said second spiral element, and said at least one additional spiral element.
8. A method according to claim 6 , wherein forming said transformer comprises:
forming a primary transformer winding from said first metal layer concurrently with said at least one digit line; and
forming a secondary transformer winding from said second metal layer concurrently with said at least one bit line.
9. A method according to claim 6 , wherein forming said transformer comprises:
forming the transformer as a primary winding and a secondary winding within areas of said first metal layer and said second metal layer that do not intersect areas of said first metal layer and said second metal layer within which said at least one digit line and said at least one bit line are formed.
10. A method according to claim 6 , wherein forming said transformer comprises:
forming said transformer as a primary winding and a secondary winding having areas within which no other electrical components are located.