ReRAM Contact Etching via Segmented Process

Solution Overview

Problem

Traditional etching processes struggle to achieve a smaller contact size and flat contact surface in resistive random-access memory (ReRAM) structures, leading to issues with device density, power consumption, and programming speed.

Innovation Solution

A two-step etching process is employed, where the first electrode layer and first barrier layer are etched to specific heights using different gases and pressures, maintaining the insulating layer as a protection layer to ensure a flat and smaller contact surface, with the first top surface area between 85 and 99% of the opening area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional etching process is used, then manufacturing simplicity is maintained, but contact size cannot be reduced and contact surface flatness is poor

Engineering Contradiction:

Improvecontact surface flatnessVSAvoidetching process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The etching process is divided into multiple sequential steps with different parameters. The first etching step uses parameters optimized for removing insulating layer material, while the second etching step uses different parameters to achieve precise contact surface formation. This segmentation allows each step to be optimized independently, achieving both flat contact surfaces and controlled contact sizes without requiring overly complex single-step processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by varying etching conditions between steps. Different etching gases, pressures, and power levels are used in successive steps to achieve the desired contact surface characteristics. This enables precise control over contact size reduction and surface flatness while managing process complexity through systematic parameter optimization.

Inventive Principle:

Principle #35Parameter changes

2Area of moving object

If traditional etching process is used, then process simplicity is maintained, but contact size cannot be reduced

Engineering Contradiction:

Improvecontact sizeVSAvoidetching process complexity

Core Design Contradiction:

Area of moving objectVSDevice complexity

Solution Approach 1:

The etching process is divided into multiple sequential steps with different parameters. The first etching step uses parameters optimized for removing insulating layer material, while the second etching step uses different parameters to achieve precise contact surface formation. This segmentation allows each step to be optimized independently, achieving both flat contact surfaces and controlled contact sizes without requiring overly complex single-step processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by varying etching conditions between steps. Different etching gases, pressures, and power levels are used in successive steps to achieve the desired contact surface characteristics. This enables precise control over contact size reduction and surface flatness while managing process complexity through systematic parameter optimization.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If contact size is reduced to improve device density, then device density improves, but contact surface uniformity deteriorates

Engineering Contradiction:

Improvedevice densityVSAvoidcontact surface uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The etching process is divided into multiple sequential steps with different parameters. The first etching step uses parameters optimized for removing insulating layer material, while the second etching step uses different parameters to achieve precise contact surface formation. This segmentation allows each step to be optimized independently, achieving both flat contact surfaces and controlled contact sizes without requiring overly complex single-step processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by varying etching conditions between steps. Different etching gases, pressures, and power levels are used in successive steps to achieve the desired contact surface characteristics. This enables precise control over contact size reduction and surface flatness while managing process complexity through systematic parameter optimization.

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 approach enhances controllability and achieves a smaller, flatter contact surface, improving device density and programming speed while maintaining the integrity of the insulating layer and preventing corner rounding.

Implementation Method 1

A two-step etching process is employed, where the first electrode layer and first barrier layer are etched to specific heights using different gases and pressures

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS9515258B2Memory structure and manufacturing method of the same

Publication Date: 2016.12.06 MACRONIX INTERNATIONAL CO LTD

AI summary

A memory structure including an insulating layer, a first electrode layer and a first barrier is provided. The insulating layer has a recess. The first electrode layer is formed in the recess and has a first top surface. The first barrier is formed between the insulating layer and the first electrode layer, and has a second top surface lower than the first top surface. The first top surface and the second top surface are lower than an opening of the recess.