Everspin Technologies, Inc.

Everpsin Technologies, Inc.

Moazzem Hossain

Sanjeev Aggarwal

Kerry Joseph Nagel

Kenneth H Smith

Sarin A Deshpande

Nicholas David Rizzo

A method of manufacturing one or more interconnects to magnetoresistive structure comprising (i) depositing a first conductive material in a via; (2) etching the first conductive material wherein, after etching the first conductive material a portion of the first conductive material remains in the via, (3) partially filling the via by depositing a second conductive material in the via and directly on the first conductive material in the via; (4) depositing a first electrode material in the via and directly on the second conductive material in the via; (5) polishing a first surface of the first electrode material wherein, after polishing, the first electrode material is (i) on the second conductive material in the via and (ii) over the portion of the first conductive material remaining in the via; and (6) forming a magnetoresistive structure over the first electrode material.

Method of integration of a magnetoresistive structure

The present disclosure is drawn to, among other things, a method of fabricating an integrated circuit device having a magnetoresistive device. In some aspects, the method includes forming the magnetoresistive device on a first contact of a substrate, wherein the magnetoresistive device includes a fixed magnetic region and a free magnetic region separated by an intermediate region; depositing a first dielectric material over the magnetoresistive device; depositing a second dielectric material over the first dielectric material; polishing a surface of the second dielectric material; forming a first cavity through the polished surface of the second dielectric material to expose a surface of the magnetoresistive device; and depositing an electrically conductive material in the first cavity to form a via.

Apparatus and methods for integrating magnetoresistive devices

A method of manufacturing one or more interconnects to a magnetoresistive structure, the method comprising depositing a first conductive material (i) in a via which is formed through a first surface of a first dielectric layer and (ii) directly on the first surface of the first dielectric layer. The method further includes etching the first conductive material wherein, after etching the first conductive material, a portion of the first conductive material remains (i) in the via and (ii) directly on the first surface of the first dielectric layer. The method also includes partially filling the via by depositing a second conductive material (i) in the via and (ii) directly on the first conductive material remaining in the via, depositing a first electrode material (i) in the via and (ii) directly on the second conductive material which is in the via, and forming a magnetoresistive structure over the first electrode material.

A layer of silicon nitride above the bottom electrode and on the sidewalls of the magnetoresistive stack serves as an insulator and an etch stop during manufacturing of a magnetoresistive device. Non-selective chemical mechanical polishing removes any silicon nitride overlying a top electrode for the device along with silicon dioxide used for encapsulation. Later etching operations corresponding to formation of a via to reach the top electrode use selective etching chemistries that remove silicon dioxide to access the top electrode, but do not remove silicon nitride. Thus, the silicon nitride acts as an etch stop, and, in the resulting device, provides an insulating layer that prevents unwanted short circuits between the via and the bottom electrode and between the via and the sidewalls of the magnetoresistive device stack.

Top electrode coupling in a magnetoresistive device using an etch stop layer

A conductive via disposed beneath a magnetic device and aligned therewith. In certain embodiments, an electrode formed on the conductive via may be polished to eliminate step functions or seams originating at the conductive via from propagating up through the various deposited layers. This integration approach allows for improved scaling of the MRAM devices to, for example, a 45 nanometer node.

A conductive via for connecting between a digit line and one side of the magnetic device is positioned beneath, and aligned with, each magnetic device. Other contacts may satisfy the same design rules, using the same process step. An electrode formed on the conductive via is polished to eliminate step functions or seams originating at the conductive via from propagating up through the various deposited layers. This integration approach allows for improved scaling of the MRAM devices to at least a 45 nanometer node, a cell packing factor approaching 6F, and a uniform thickness of material between the bit lines and the underlying memory elements.

Magnetic random access memory integration having improved scaling

A method is provided for forming a first via with an electrically conductive material, for example, copper, that is formed over and coupled to a conductive landing pad of an MRAM array. A sputter step is performed to lower the surface of the first via below that of a surrounding dielectric material. This recess is repeated in subsequent processing steps, providing alignment marks for the formation of a magnetic tunnel junction. The magnetic tunnel junction may be offset from the first via, and a second via being formed above the magnetic tunnel junction and to a conductive layer.

Growing community of inventors

Chandler, AZ, United States of America

Moazzem Hossain