Phase Change Memory Gap-Filling via Plasma and Low-Temp Heat

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Solution Overview

Problem

Phase change memory devices face challenges in achieving good gap-filling characteristics due to poor step coverage of the phase change material layer, leading to voids or seams, which are difficult to address without damaging the device through high-temperature heat treatments.

Innovation Solution

A method involving a plasma treatment process to remove the oxide layer on the phase change material layer, followed by a heat treatment at a lower temperature to fill the opening without forming additional oxides, ensuring the layer is free of voids and seams, is employed. This process maintains a high vacuum state to prevent oxide layer formation and uses specific gases like hydrogen and argon.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high temperature heat treatment is applied to fill voids or seams in the phase change material layer, then the gap-filling characteristics are improved, but the device may be damaged

Engineering Contradiction:

Improvegap-filling characteristicsVSAvoiddevice damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the temperature parameter from high temperature to low temperature heat treatment, and introduces plasma treatment as a preparatory step. This parameter change allows effective void and seam removal without causing device damage that would occur with high temperature treatment.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention applies plasma treatment before heat treatment to remove oxide layers from the phase change material layer surface. This preliminary action prepares the surface for more effective low-temperature heat treatment, enabling good gap-filling characteristics without requiring high temperatures that could damage the device.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If the phase change material layer is deposited to fill the opening, then the gap-filling is improved, but voids or seams remain due to poor step coverage

Engineering Contradiction:

Improvegap-filling characteristicsVSAvoidpresence of voids or seams

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention performs plasma treatment and low-temperature heat treatment as preliminary actions after deposition. These treatments remove oxide layers and fill voids or seams that form during deposition due to poor step coverage, thereby improving gap-filling characteristics and reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention utilizes phase transition during low-temperature heat treatment to fill voids and seams in the phase change material layer. The material undergoes phase change that enables it to flow and fill gaps, improving gap-filling characteristics without requiring high temperatures.

Inventive Principle:

Principle #36Phase transitions

3Manufacturing precision

If plasma treatment is performed to remove oxide layer, then the subsequent heat treatment effectiveness is improved, but additional oxide layers may form if vacuum is not maintained

Engineering Contradiction:

Improveheat treatment effectivenessVSAvoidoxide layer formation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention maintains high vacuum conditions (below 10^-7 Torr) during the transition between plasma treatment and heat treatment, and during heat treatment. This inert environment prevents oxidation of the phase change material layer surface, ensuring that the plasma treatment effectiveness is not negated by subsequent oxide formation.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively fills the openings without high-temperature treatments, ensuring the phase change material layer has no voids or seams, thereby improving the electrical characteristics of the phase change memory devices.

Implementation Method 1

performing a plasma treatment process on the phase change material layer to remove an oxide layer on a surface of the phase change material layer

Methodology Applied

Scientific EffectPlasma etching: Plasma

Implementation Method 2

performing a heat treatment process on the phase change material layer to remove a void or a seam in the phase change material layer, sufficiently filling the opening

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

The phase change material layer may be maintained at a pressure below about 10−7 Ton between the plasma treatment process and the heat treatment process, preventing formation of another oxide layer on the phase change material layer

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentUS8865558B2Method of forming a phase change material layer pattern and method of manufacturing a phase change memory device

Publication Date: 2014.10.21 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of forming a phase change material layer pattern includes forming a phase change material layer partially filling an opening through an insulating interlayer. A plasma treatment process is performed on the phase change material layer to remove an oxide layer on a surface of the phase change material layer. A heat treatment process is performed on the phase change material layer to remove a void or a seam in the phase change material layer, sufficiently filling the opening.