Semiconductor Passivation Layer Surface Treatment for Etching

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Solution Overview

Problem

In semiconductor device fabrication, forming a passivation layer on high aspect ratio structures is challenging due to condensation defects that hinder etching processes and reduce yield rates, as residual passivation layers often remain at the bottom of openings, causing leakage currents and poor electrical performance.

Innovation Solution

A method involving the formation of a composite or single passivation layer with varying hydrophobicity and oxygen content, where the treated surface properties differ from the inner surface, allowing for effective removal of the passivation layer from the bottom part of the opening during an etching process, preventing condensation defects and residue formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passivation layer is formed on the sidewall of the opening to prevent leakage current, then electrical performance is improved, but condensation defects occur and residual passivation layer remains at the bottom part of the opening

Engineering Contradiction:

Improveelectrical performanceVSAvoidresidual passivation layer

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The passivation material layer is treated to create different surface properties at different locations. The first surface (exposed to reaction gas) is made more hydrophobic through treatment processes, while the second surface (facing the opening bottom) maintains different properties. This local quality difference enables selective removal during etching, resolving the contradiction between forming complete sidewall passivation and preventing bottom residue

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The surface treatment is performed on the passivation material layer before the etching process. By preliminarily modifying the surface properties (making the first surface more hydrophobic), the subsequent etching process can selectively remove the passivation layer from the bottom part of the opening while preserving it on the sidewall, preventing residual defects before they occur

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the passivation layer is formed completely on the sidewall, then leakage current is prevented, but the etching process is hindered by condensation defects

Engineering Contradiction:

Improveleakage current preventionVSAvoidetching process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Different regions of the passivation material layer are given different surface properties through selective treatment. The first surface exposed to reaction gas becomes more hydrophobic, preventing condensation that would hinder etching, while the passivation function on the sidewall is maintained. This resolves the contradiction between complete passivation and etching processability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The treatment process intentionally creates surface property differences that could be seen as modifying the passivation layer, but this modification actually benefits the etching process by preventing condensation defects. The harmful condensation is converted into a beneficial hydrophobic surface that facilitates smooth etching while maintaining passivation functionality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 ensures the passivation layer is formed only on the sidewall, eliminating leakage currents and improving electrical performance while significantly reducing yield loss, especially in smaller critical dimensions, by preventing condensation defects and enhancing the removal of the passivation layer from the bottom part of the opening.

Implementation Method 1

A treatment process is performed to the first passivation material layer to form a second passivation material layer. In addition, a first surface of the second passivation material layer and a second surface of the second passivation material layer differ in a property

Methodology Applied

Scientific EffectSurface treatment process:

Data Source

PatentUS10607848B2Method of fabricating semiconductor device

Publication Date: 2020.03.31 MACRONIX INTERNATIONAL CO LTD

AI summary

Provided is a method of fabricating a semiconductor device including the following steps. A substrate is provided. A material layer having an opening is formed on the substrate. A first passivation material layer is formed on sidewalls of the opening and on the substrate. A treatment process is performed to the first passivation material layer to form a second passivation material layer. A first surface of the second passivation material layer and a second surface (at an inner side) of the second passivation material layer are differ in a property, and the first surface is located at a side of the second passivation material layer relatively away from the material layer.