Self-aligned top contact for MRAM fabrication

摘要

Systems and methods for forming precise and self-aligned top metal contact for a Magnetoresistive random-access memory (MRAM) device include forming a magnetic tunnel junction (MTJ) in a common interlayer metal dielectric (IMD) layer with a logic element. A low dielectric constant (K) etch stop layer is selectively retained over an exposed top surface of the MTJ. Etching is selectively performed through a top IMD layer formed over the low K etch stop layer and the common IMD layer, based on a first chemistry which prevents etching through the low K etch stop layer. By switching chemistry to a second chemistry which precisely etches through the low K etch stop layer, an opening is created for forming a self-aligned top contact to the exposed top surface of the MTJ.

主权项

1. A method of forming a top contact for a Magnetoresistive random-access memory (MRAM) device, the method comprising:
forming a magnetic tunnel junction (MTJ) in a common interlayer metal dielectric (IMD) layer; forming a low dielectric constant (K) etch stop layer over an exposed top surface of the MTJ; selectively etching through a top IMD layer formed over the low K etch stop layer and the common IMD layer, based on a first chemistry which prevents etching the low K etch stop layer; and switching chemistry to a second chemistry which precisely etches through the low K etch stop layer, to create an opening for forming a self-aligned top contact to the exposed top surface of the MTJ.