Resistive Memory Device Lateral Recesses for Etch Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Resistive memory material portions in semiconductor devices are prone to collateral damage during the etch process that removes sacrificial material layers, leading to inefficiencies in manufacturing three-dimensional monolithic memory arrays.

Innovation Solution

A method is developed to form resistive memory devices by selectively growing resistive memory material portions from exposed surfaces of conductive lines within lateral recesses, avoiding direct contact with etching agents that damage these materials, and replacing sacrificial layers with electrically conductive layers without harming the resistive memory material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the etch process is used to remove sacrificial material layers, then the manufacturing process can proceed, but collateral damage occurs to resistive memory material portions

Engineering Contradiction:
Improvemanufacturing process progressionVSAvoidintegrity of resistive memory material
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent extracts the harmful etching action from the vicinity of resistive memory material portions by forming lateral recesses that physically separate the sacrificial material layers from the memory material. This allows the etch process to remove sacrificial material without contacting and damaging the resistive memory material portions, thus resolving the contradiction between process progression and material integrity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces lateral recesses as an intermediary structure between the sacrificial material layers and the resistive memory material portions. These recesses act as protective zones that enable the etch process to proceed while preventing direct contact between the etching agents and the sensitive memory material, thereby maintaining reliability while ensuring productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If sacrificial material layers are removed by etching, then the structure can be simplified, but resistive memory material portions suffer collateral damage

Engineering Contradiction:
Improvestructure simplificationVSAvoiddamage to memory material
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the structure by creating lateral recesses that divide the space between sacrificial material layers and memory material portions. This segmentation allows the etch process to selectively remove sacrificial material in specific zones without affecting the memory material, thus achieving structure simplification while maintaining manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating lateral recesses only in specific locations where sacrificial material needs to be removed. This localized structural modification enables selective etching in areas where it is needed while protecting memory material portions, resolving the contradiction between simplification and precision.

Inventive Principle:
Principle #3Local quality

3Productivity

If conventional manufacturing methods are used, then production can proceed efficiently, but resistive memory material portions are damaged during etching

Engineering Contradiction:
Improveproduction efficiencyVSAvoidcollateral damage from etching
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary action by forming lateral recesses before the etch process removes sacrificial material layers. This advance preparation creates protective zones that prevent collateral damage during subsequent etching steps, allowing efficient production while eliminating the harmful effect of etching on memory material portions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies preliminary anti-action by creating lateral recesses that preemptively counteract the harmful effects of the etch process. These recesses are formed in advance to block or redirect etching agents away from resistive memory material portions, thus neutralizing the potential damage before it can occur during production.

Inventive Principle:
Principle #9Preliminary anti-action

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

This approach prevents collateral damage to resistive memory material portions, enhancing the reliability and performance of resistive random access memory devices by ensuring the integrity of the memory material during the manufacturing process.

Implementation Method 1

selectively growing resistive memory material portions from physically exposed surfaces of the vertical conductive lines and not from the surfaces of the insulating layers and the dielectric pillar structures in the lateral recesses

Methodology Applied
Scientific EffectSelective deposition: Deposition (physical)

Data Source

PatentEP3619752B1Resistive random access memory device containing replacement word lines and method of making thereof
Publication Date: 2021.05.05 SANDISK TECHNOLOGIES LLC
  • EP3619752B1 patent drawingFigure 1
  • EP3619752B1 patent drawingFigure 2A
  • EP3619752B1 patent drawingFigure 2B

AI summary

A method of forming a resistive memory device includes forming an alternating stack of insulating layers and sacrificial material layers that extend along a first horizontal direction over a substrate, forming a laterally alternating sequence of vertical conductive lines and dielectric pillar structures that alternate along the first horizontal direction on sidewalls of the alternating stack, forming lateral recesses by removing the sacrificial material layers selective to the insulating layers, selectively growing resistive memory material portions from physically exposed surfaces of the vertical conductive lines in the lateral recesses, and forming electrically conductive layers over the resistive memory material portions in the lateral recesses.