Patent ID: 11963457
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A method comprising:
forming a conductive layer on a top surface of a substrate;
modifying the conductive layer to have a concave top surface;
forming a stack of magnetic tunneling junction (MTJ) layers on the concave top surface of the conductive layer, wherein the stack of MTJ layers includes a first layer and a second layer disposed over the first layer, wherein the first layer and the second layer in the stack of MTJ layers have respective concave top surfaces, wherein defects associated with forming the first layer migrate to a first portion of the first layer during the forming of the stack of MTJ layers, wherein the concave top surface of the first layer in the stack of MTJ layers spans a first distance over the substrate and the concave top surface of the second layer in the stack of MTJ layers spans a second distance after the forming of the stack of MTJ layers, wherein the first and second distances are measured along a first direction that is substantially parallel to the top surface of the substrate, wherein the first distance is different than the second distance, wherein the first portion of the first layer has a flat top surface that is substantially parallel to the top surface of the substrate after the forming of the stack of the MTJ layers, wherein the first portion of the first layer physically contacts the top surface of the substrate after the forming of the stack of MTJ layers; and
removing the first portion of the first layer that contains defects and a portion of the concave top surface of the conductive layer to thereby expose the top surface of the substrate.