RRAM Manufacturing Uniform Resistance via Flat Metal Layer

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Solution Overview

Problem

The manufacturing process of conventional resistive random access memory (RRAM) results in uneven distribution of resistance, leading to inefficiencies in storage units.

Innovation Solution

A method involving forming a resistance layer on a flat first metal layer, followed by a passivation layer, etching to create basic units, depositing an insulating dielectric layer, forming contacting holes, and filling with a metal wire, ensures uniform resistance distribution by avoiding uneven oxidization and surface differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the conventional manufacturing process (filling tungsten plug, grinding and oxidizing) is used, then the manufacturing process is compatible with conventional MOS process, but the resistance distribution on the wafer becomes uneven

Engineering Contradiction:

Improveprocess compatibilityVSAvoidresistance distribution uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by first forming a flat metal layer base before depositing the resistance layer. This preliminary flat surface preparation ensures that subsequent oxidation produces uniform resistance distribution, preventing the unevenness that occurs when oxidizing irregular tungsten plugs. The flat base layer is prepared in advance to create optimal conditions for the resistance layer formation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary flat metal layer between the substrate and the resistance layer. This intermediary layer serves as a mediator that provides a flat surface for resistance layer deposition, thereby ensuring uniform oxidation and resistance distribution while maintaining compatibility with conventional MOS manufacturing processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If tungsten plug grinding and oxidizing is performed, then a resistance layer can be formed, but uneven oxidization occurs leading to wire width limitations

Engineering Contradiction:

Improveresistance layer formationVSAvoidoxidation uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical parameter of the metal layer surface from irregular (grinded tungsten plugs) to flat (planarized metal layer). This parameter change in surface topology ensures uniform oxidation kinetics across the entire resistance layer, eliminating the wire width limitations and oxidation non-uniformity that plague the conventional approach.

Inventive Principle:

Principle #35Parameter changes

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 method achieves uniform resistance distribution, enhancing the manufacturing process by preventing uneven oxidization and wire width limitations, thus improving the performance and reliability of RRAM storage units.

Implementation Method 1

oxidizing the resistance substrate layer to obtain an oxide of the resistance substrate layer, a resistance layer is formed

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

depositing a insulating dielectric layer, and flattening the insulating dielectric layer

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

depositing a nitride layer on the resistance layer by performing a chemical vapor deposition process

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS9153781B2Method for manufacturing resistive random access storage unit

Publication Date: 2015.10.06 CSMC TECH FAB2 CO LTD

AI summary

A manufacturing method of a resistive random access storage unit, includes: forming a resistance layer on a first metal layer having a flat surface; forming a passivation layer on the resistance layer; performing an etching process to obtain a plurality of basic units, a basic unit comprising a first metal layer, a resistance layer, and a passivation layer, which are laminated sequentially; depositing a insulating dielectric layer, and flattening the insulating dielectric layer; etching the insulating dielectric layer and the passivation layer to form contacting holes corresponded to the basic units; filling metal wires in the contacting holes; forming a second metal layer. According to the above method, a uniformly distributed resistance can be formed on a whole wafer.