Magnetic random access memory integration having improved scaling
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 2 , and a uniform thickness of material between the bit lines and the underlying memory elements.
1. A method of manufacturing a magnetic element, the method comprising:
forming a first via in a first portion of a first dielectric material;
forming a first conductive material in the first via and on a second portion of the first dielectric material;
forming a second conductive material in the first via and on the first conductive material which is in the first via and on the second portion of the first dielectric material;
forming a first electrode (i) over the first conductive material, (ii) on the second conductive material which is in the first via and over the second portion of the first dielectric material, and (iii) in the first via and on the second conductive material which is in the first via:
polishing the first electrode. by a chemical mechanical polish, to provide a polished first electrode, leaving a portion of the first electrode (i) over the first conductive material and (ii) on the second conductive material which is in the first via and over the second portion of the first dielectric material; and
forming a magnetic bit over the polished first electrode and aligned with the first via.
2. The method of claim 1 further comprising:
etching a portion of the first conductive material before forming the second conductive material on the first conductive material.
3. The method of claim 2 wherein forming the first conductive material, etching a portion of the first conductive material, and forming the second conductive material are performed in-situ.
4. The method of claim 2 wherein the first and second conductive materials are metals.
5. The method of claim 1 further comprising:
forming more electrode material on the first electrode subsequent to the polishing the first electrode.
6. The method of claim 1 further comprising:
forming a second electrode over the magnetic bit;
forming a chemical mechanical polish stop layer over the second electrode;
forming a second dielectric layer over the chemical mechanical polish stop layer;
polishing to the chemical mechanical polish stop layer;
forming an etch stop layer over the chemical mechanical polish stop layer;
forming a third dielectric layer over the etch stop layer;
etching an opening in the third dielectric layer, the etch stop layer, and the chemical mechanical polish stop layer above and to the second electrode; and
forming a third conductive material within the opening and on the second electrode.
7. The method of claim 1 wherein forming the first conductive material consists of forming one of tungsten or ruthenium.
8. The method of claim 1 wherein the first conductive material comprises tantalum or tantalum-nitride.
9. The method of claim 8 wherein the first electrode comprises tantalum or tantalum-nitride.
10. The method of claim 1 wherein forming a magnetic bit over the polished first electrode further includes forming the magnetic bit on the polished first electrode.
11. A method of manufacturing a magnetic element, the method comprising:
etching a via through a first dielectric layer;
forming a first conductive material in the via and on a portion of the first dielectric layer;
etching a portion of the first conductive material wherein after etching, a portion of the first conductive material remains in the via and on the portion of the first dielectric layer;
forming a second conductive material on the first conductive material remaining in the first via and over the portion of the first dielectric layer, wherein a portion of the second conductive layer is in the via, and wherein the first and second conductive materials are metals;
forming a first electrode on the second conductive material which is in the via and on the portion of the first dielectric layer;
polishing a first surface of the first electrode to provide a polished first surface, leaving a portion of the first electrode (i) on the second conductive material and (ii) over the portion of the first dielectric layer; and
forming a magnetic bit on the polished first surface and in electrical contact with the first conductive material.
12. The method of claim 11 further comprising:
forming a second electrode over the magnetic bit;
forming a chemical mechanical polish stop layer over the second electrode and the magnetic hit;
forming a second dielectric layer over the chemical mechanical polish stop layer;
polishing to the chemical mechanical polish stop layer;
forming an etch stop layer over the chemical mechanical polish stop layer;
forming a third dielectric layer over the etch stop layer;
etching an opening in the third dielectric layer, the etch stop layer, and the chemical mechanical polish stop layer above and to the second electrode; and
forming a third conductive material within the opening and on the second electrode.
13. The method of claim 11 wherein the magnetic bit is one of a plurality of magnetic bits forming an array.
14. The method of claim 11 wherein forming the first and second conductive materials comprise a process also used to form other electrical contacts on an array containing the magnetic element.
15. A method of manufacturing a magnetic element, the method comprising:
etching a first via through a first portion of a first dielectric layer;
forming a first conductive material in the first via and on a second portion of the first dielectric layer;
forming a second conductive material on the first conductive material which is in the first via and on the second portion of the first dielectric layer;
forming a first electrode (i) over the first conductive material which is on the second portion of the first dielectric layer, (ii) on the second conductive material which is on the first conductive material that is in the first via and (iii) in the first via and on the second conductive material which is in the first via;
polishing the first electrode, by a chemical mechanical polish, to provide a polished electrode, leaving a portion of the first electrode (i) over the first dielectric layer and the first conductive material and (ii) on the second conductive material which is on the first conductive material that is in the first via; and
forming a magnetic bit over the polished electrode.
16. The method of claim 15 wherein forming the first conductive material, forming the second conductive material, and forming the electrode are performed in-situ.
17. The method of claim 15 further comprising:
forming a second electrode over the magnetic bit;
forming a chemical mechanical polish stop layer over the second electrode;
forming a second dielectric layer over the chemical mechanical polish stop layer;
polishing to the chemical mechanical polish stop layer;
forming an etch stop layer over the chemical mechanical polish stop layer;
forming a third dielectric layer over the etch stop layer;
etching an opening in the third dielectric layer, the etch stop layer, and the chemical mechanical polish stop layer above and to the second electrode; and
forming a third conductive material within the opening and on the second electrode.
18. The method of claim 15 wherein:
the first conductive material comprises tantalum or tantalum-nitride, and
the first electrode comprises tantalum or tantalum-nitride.
19. The method of claim 18 wherein forming a magnetic hit over the polished first electrode further includes forming the magnetic bit on the polished first electrode.
20. The method of claim 15 further comprising:
etching the first conductive material before forming the second conductive material on the first conductive material wherein, after etching the first conductive material, a portion of the first conductive material remains in the first via.
21. The method of claim 20 wherein forming the first conductive material, etching a portion of the first conductive material, and forming the second conductive material are performed in-situ.
22. A method of manufacturing a magnetic element, the method comprising:
etching a first via through a first portion of a first dielectric layer;
forming a first conductive material in the first via and on a second portion of the first dielectric layer;
forming a second conductive material on the first conductive material which is in the first via and on the second portion of the first dielectric layer;
forming a first electrode (i) over the first conductive material which is on the second portion of the first dielectric layer and (ii) on the second conductive material which is on the first conductive material that is in the first via, wherein forming the first conductive material, forming the second conductive material, and forming the first electrode are performed in-situ;
polishing the first electrode to provide a polished electrode, leaving a portion of the first electrode (i) over the first dielectric layer and the first conductive material and (ii) on the second conductive material which is on the first conductive material that is in the first via; and
forming a magnetic bit over the polished electrode.
23. The method of claim 22 wherein:
the first conductive material comprises tantalum or tantalum-nitride, and
the first electrode comprises tantalum or tantalum-nitride.
24. The method of claim 23 wherein forming a magnetic bit over the polished first electrode further includes forming the magnetic hit on the polished first electrode.
25. The method of claim 22 further comprising:
etching the first conductive material before forming the second conductive material on the first conductive material wherein, after etching the first conductive material, a portion of the first conductive material remains in the first via.
26. The method of claim 22 further comprising:
forming a second electrode over the magnetic bit;
forming a chemical mechanical polish stop layer over the second electrode;
forming a second dielectric layer over the chemical mechanical polish stop layer;
polishing to the chemical mechanical polish stop layer;
forming an etch stop layer over the chemical mechanical polish stop layer;
forming a third dielectric layer over the etch stop layer;
etching an opening in the third dielectric layer, the etch stop layer, and the chemical mechanical polish stop layer above and to the second electrode; and
forming a third conductive material within the opening and on the second electrode.