Combined CMP and RIE contact scheme for MRAM applications

Patent metadata

Field	Value
Publication number	US-10014464-B1
Application number	US-201715446592-A
Country	US
Kind code	B1
Filing date	Mar 1, 2017
Priority date	Mar 1, 2017
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A method is presented for establishing a top contact to a magnetic tunnel junction (MTJ) device, the method including selectively etching, via a first etching process, an oxide layer to expose a top surface of a nitride layer of a dummy fill shape and selectively etching, via a second etching process, a top portion of the nitride layer of the dummy fill shape to expose a top surface thereof. The method further includes selectively etching, via the second etching process, the oxide layer to expose a top surface of a nitride layer of the MTJ device, and selectively etching, via the first etching process, a top portion of the nitride layer of the MTJ device to expose a top surface thereof such that a height of the MTJ device is approximately equal to a height of the dummy fill shape.

First claim

What is claimed is:

1. A semiconductor structure for establishing a top contact to a magnetic tunnel junction (MTJ) device, the structure comprising:
the MTJ device; and
a dummy fill shape, the MTJ device and dummy fill shape planarized by alternating selective chemical-mechanical planarization (CMP) and reactive ion etch (RIE) processes such that:
a first dielectric layer is selectively etched by CMP to expose a top surface of a second dielectric layer of the dummy fill shape;
a top portion of the second dielectric layer of the dummy fill shape is selectively etched by RIE to expose a top surface thereof;
the first dielectric layer is selectively etched by RIE to expose a top surface of a third dielectric layer of the MTJ device; and
a top portion of the third dielectric layer of the MTJ device is selectively etched by CMP to expose a top surface thereof such that a height of the MTJ device is approximately equal to a height of the dummy fill shape.

2. The structure of claim 1 , wherein the dummy fill shape has a first height and the MTJ device has a second height, the first height being greater than the second height.

3. The structure of claim 1 , wherein etching via CMP is lased on a predetermined height offset between the dummy fill shape and the MTJ device.

4. The structure of claim 1 , wherein MTJ device one of a plurality of MTJ devices defining a uniform top contact across a wafer without exposure to reactive plasma chemistries.

Assignees

• IBM

Inventors

• Lofaro Michael F
• Marchack Nathan P
• Nowak Janusz J
• O'Sullivan Eugene J

Classifications

• H01L43/02

  Electricity · mapped topic

• H01L27/222

  Electricity · mapped topic

• H01L43/08

  Electricity · mapped topic

• H01L43/12 Primary

  Electricity · mapped topic

• H10N50/01 Primary

  Manufacture or treatment · CPC title