Structure and method for formation of cladded interconnects for MRAMs
US7442647B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 2008 |
| Grant date | Oct 28, 2008 |
| Priority date | — |
| Expiry date | Mar 5, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76849
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A structure and method for fabricating a top strap in a magnetic random access memory, MRAM, comprising a damascene process forming a trench in a dielectric layer and resulting in a metal conductor clad on three sides by an inverted U-shape trench liner and cap made up of three layers consisting of a stack of a ferromagnetic material sandwiched between two layers of a refractory metal or an alloy of a refractory metal. First the two sidewalls of the trench are formed with the cladding layer, followed by filling the trench with the metal conductor. In preparing the structure for the capping layer, the metal conductor is recessed with an etch that is selective to the metal conductor over the sidewall stack. This preparation may be performed on selected metal filled trenches and blocked on others, such that after a final polishing step, only those metal conductors that received the recess operation will have the capping layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.