Sacrificial Layer for Safe Semiconductor Mask Removal

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Solution Overview

Problem

During the fabrication of semiconductor devices, the removal of masks containing nitride or oxide can damage the underlying substrate, leading to degradation of electrical characteristics.

Innovation Solution

A method involving the formation of a sacrificial layer, which is etched and used to protect the lower layer, allowing for the safe removal of the mask without damaging the substrate, using materials like organic silicon, photoresist, or polymer layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a mask containing nitride or oxide is used and then removed, then the mask can be easily formed and removed, but the underlying substrate or lower structure is damaged during mask removal

Engineering Contradiction:

Improveease of mask formation and removalVSAvoiddamage to substrate or lower structure

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A sacrificial layer is introduced as an intermediary between the mask and the lower structure. This sacrificial layer is specifically designed to be selectively removed after the mask is removed, thereby protecting the lower structure from damage. The sacrificial layer acts as a buffer that absorbs the harmful effects of mask removal processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sacrificial layer is formed in advance before the mask is applied. This preliminary action ensures that protective coverage is already in place before any potentially damaging operations occur. The sacrificial layer is positioned and prepared beforehand to intercept and mitigate damage during subsequent mask removal steps.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the mask is removed using etch back process, then the mask can be effectively removed, but the lower layer may be exposed and damaged

Engineering Contradiction:

Improveefficiency of mask removalVSAvoidintegrity of lower layer

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The sacrificial layer serves as a protective intermediary during the etch back process. It allows the mask to be removed efficiently via etch back while the sacrificial layer remains in place to shield the lower layer from exposure and damage. The sacrificial layer is selectively etched only after the mask removal is complete.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sacrificial layer provides beforehand cushioning protection to the lower layer during the mask removal process. It is positioned in advance to absorb and mitigate the harmful effects of the etch back process, ensuring that the lower layer remains protected even when aggressive removal techniques are employed.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If no protective layer is used during mask removal, then the process is simple and fast, but the substrate or lower structure suffers damage

Engineering Contradiction:

Improvesimplicity of mask removal processVSAvoiddamage to substrate or lower structure

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The sacrificial layer is designed as a disposable, temporary protective element. It is easily formed and even more easily removed after serving its protective function. This disposable approach maintains process simplicity while providing necessary protection, as the sacrificial layer can be quickly deposited and just as quickly removed after mask removal is complete.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The sacrificial layer acts as a temporary intermediary that simplifies the overall process by enabling direct mask removal without complex protective measures. It provides the necessary protection during the critical removal phase, then is easily discarded, maintaining process simplicity while preventing damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively prevents damage to the substrate during mask removal, maintaining the integrity and electrical performance of the semiconductor device.

Implementation Method 1

The underlying layer is etched using the mask as an etching mask to form patterns. The sacrificial layer in the opening is partially etched when the mask is removed.

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

The sacrificial layer may be removed using an ashing or strip process.

Methodology Applied

Scientific EffectAashing:

Data Source

PatentUS8481426B2Method of forming pattern structure and method of fabricating semiconductor device using the same

Publication Date: 2013.07.09 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of forming a pattern structure and a method of fabricating a semiconductor device using the pattern structure, are provided the method of forming the pattern structure includes forming a mask on an underlying layer formed on a lower layer. The underlying layer is etched using the mask as an etching mask, thereby forming patterns on the lower layer. The patterns define at least one opening. A sacrificial layer is formed in the opening and the mask is removed. The sacrificial layer in the opening is partially etched when the mask is removed.