Pillar Passivation Material for Trench Etching

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Solution Overview

Problem

Existing semiconductor fabrication processes face challenges in protecting the top region of pillars adjacent trenches during etching, leading to unintended consequences such as material removal, edge rounding, and critical dimension drifts due to the lack of effective passivation materials with sufficient etch resistance.

Innovation Solution

A cyclic process involving the deposition and selective removal of a hydrocarbon polymer passivation material is used to form a barrier on the top region of pillars, ensuring it has a higher etch resistance than the substrate material, thereby protecting the pillar from etching at the bottom region of the trench and maintaining critical dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If no passivation material is used on the top region of the pillar, then the etching process can proceed without additional steps, but the top region of the pillar suffers from material removal, edge rounding, and critical dimension drifts

Engineering Contradiction:

Improvecritical dimension control of pillar top regionVSAvoidfabrication process steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A passivation material is deposited on the top region of the pillar before the etching process to protect it from material removal and edge rounding. This preliminary protective action prevents the harmful effects of etching on the pillar top region, maintaining critical dimensions throughout the fabrication process.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a passivation material with high etch resistance is applied on the top region of the pillar, then the pillar is protected from etching damage, but the trench etching process becomes more difficult due to the barrier effect

Engineering Contradiction:

Improveprotection of pillar top regionVSAvoidtrench etching process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The passivation material is selectively applied only to the top region of the pillar, creating a localized protective layer with different etch resistance properties than the surrounding areas. This local quality enhancement protects the pillar top region while allowing the trench etching process to proceed effectively in other areas.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If the passivation material is left on the trench sidewalls after etching, then the pillar top region remains protected, but the trench width increases and sidewall roughness increases

Engineering Contradiction:

Improvepillar top region dimension controlVSAvoidtrench width and sidewall smoothness

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The passivation material is applied dynamically during the etching process with controlled deposition and removal timing. The material is deposited on the pillar top region before etching, then selectively removed after etching to maintain protection during the process while preventing final accumulation that would affect trench dimensions and sidewall quality.

Inventive Principle:

Principle #15Dynamics

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 effectively prevents material removal and edge rounding, maintains the original dimensions of the top region of the pillar, and reduces the width and roughness of the trench, ensuring precise semiconductor device fabrication.

Implementation Method 1

The protection may be conferred by a passivation material that forms a barrier over the top region having a resistance to an etching procedure that is higher than a resistance of the substrate material being etched

Methodology Applied

Scientific EffectEtch resistance:

Implementation Method 2

A cyclic process involving the deposition and selective removal of a hydrocarbon polymer passivation material is used to form a barrier on the top region of pillars

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS10665665B2Passivation material for a pillar adjacent a trench

Publication Date: 2020.05.26 MICRON TECHNOLOGY INC

AI summary

Systems, apparatuses, and methods related to passivation material for a pillar adjacent a trench are described. An example method includes forming a passivation material on a top region of a pillar adjacent a trench of a semiconductor device and removing a first portion of the passivation material to form, on a remaining second portion of the passivation material, a surface that is coplanar with an underlying sidewall of the pillar. The example method further includes removing a portion of a substrate material at a bottom region of the trench and removing the remaining second portion of the passivation material from the top region.