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Combined physical and chemical etch for magnetic tunnel junction patterning

A magnetic tunneling junction and etching technology, applied in microstructure technology, microstructure devices, magnetic field controlled resistors, etc., can solve the problems of low yield, difficult to repair side walls, and increased cost.

Inactive Publication Date: 2020-03-31
TAIWAN SEMICON MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Furthermore, damaged sidewalls are difficult to repair and generally result in lower yields and thus higher cost per unit of acceptable product

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  • Combined physical and chemical etch for magnetic tunnel junction patterning
  • Combined physical and chemical etch for magnetic tunnel junction patterning
  • Combined physical and chemical etch for magnetic tunnel junction patterning

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Embodiment Construction

[0023]The present disclosure is a method of etching an MTJ layer stack in which all layers under a hard mask are removed using a single etch process that includes both physical and chemical components to form MTJ nanopillars , with substantially less sidewall damage and minimal residue compared to conventional methanol-based reactive ion etching. An alternative process sequence is provided in which physical and chemical etchant are used alternately or in separate steps followed by chemical treatment and optional volatilization to achieve better magnetic tunneling junction performance. Although only one MTJ nanocolumn is shown in the figure, those skilled in the art should understand that a plurality of MTJ nanocolumns can be formed in a typical memory device pattern. A process is defined as a method comprising one or more steps, and according to the present disclosure a sequence or process flow refers to two or more processes in succession.

[0024] refer to figure 1 , showi...

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Abstract

Processes for forming magnetic tunnel junction (MTJ) nanopillars (la) with minimal sidewall residue and damage are disclosed wherein a pattern is first formed in a hard mask (15) that is an uppermostMTJ layer. Thereafter, the hard mask sidewall (20) is etch-transferred through the remaining MTJ layers including a tunnel barrier (13) between a free layer (14) and a reference layer (12). The etching may be completed in a single RIE step (32m) that features a physical component involving inert gas ions or plasma, and a chemical component comprising ions or plasma generated from one or more of methanol, ethanol, ammonia, and carbon monoxide. Alternatively, a chemical treatment (33) with one of the aforementioned chemicals, and a volatilization step (34v) may follow MTJ stack patterning usingan ion beam etch or RIE involving inert gas ions (32i).

Description

technical field [0001] The present disclosure relates to a method for reducing sidewall damage of a magnetic tunnel junction (MTJ) during an etching process. The etching process transfers a mask pattern through the MTU layer stack, thereby producing MTU nanopillars. Array, which has better magnetoresistance ratio and other magnetic properties. Background technique [0002] Magnetic tunnel junction memory elements, also known as magnetic tunnel junction nanocolumns, are key components in magnetic recording devices and memory devices. Memory devices such as magnetoresistive random access memory (magnetoresistive random access memory, MRAM) and Spin torque transfer (spin torque transfer, STT) magnetoresistive random access memory. An important step in the fabrication of the MTJ array is to transfer the pattern in the overlying hard mask to the MTJ stack layer by etching to form a magnetic tunnel with a critical dimension (CD). Tunneling surface nanopillar arrays have critical...

Claims

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Application Information

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IPC IPC(8): H01L43/12
CPCH10N50/01H01L21/3065H01L21/308H01L21/30604B81C1/00111B81C1/00523B82Y40/00H10N50/10
Inventor 沈冬娜王郁仁童儒颖维格纳许·桑达沙希·帕特尔
Owner TAIWAN SEMICON MFG CO LTD