Photoresist Pattern Resolution via Polarity Conversion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current photo-lithography processes for forming patterns in semiconductor devices face challenges in achieving high resolution due to limitations in the chemical properties and reactions of photoresist layers, which affect the accuracy and stability of the pattern formation.

Innovation Solution

A method involving the sequential formation of a lower coating layer and a photoresist layer, where the lower coating layer includes a polarity conversion group that undergoes a dehydration reaction upon exposure, converting from hydrophilic to hydrophobic properties, allowing for improved adhesion and affinity with the photoresist pattern, enabling selective removal of the non-exposed portion and precise etching of the object layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional photoresist layers are used without polarity conversion groups, then the photo-lithography process is simpler, but the resolution and adhesion between layers deteriorate

Engineering Contradiction:

Improvepattern resolutionVSAvoidcoating layer structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The lower coating layer incorporates polarity conversion groups at specific locations (in the exposed portions) to create local hydrophobic regions that enhance adhesion to the photoresist pattern. This localized modification improves pattern resolution without requiring complete structural redesign of the entire coating system.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The lower coating layer is designed as a composite material containing both the base polymer and polarity conversion groups (such as tertiary alcohol groups). This composite structure combines the fundamental coating properties with enhanced chemical reactivity and adhesion characteristics, resolving the contradiction between simplicity and performance.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If polarity conversion groups are added to improve adhesion, then pattern stability improves, but the chemical reaction complexity increases

Engineering Contradiction:

Improvepattern stabilityVSAvoidchemical reaction process

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The polarity conversion groups undergo a parameter change from hydrophilic to hydrophobic state upon exposure to light. This parameter transformation (change in polarity) enhances pattern stability by improving adhesion between the lower coating layer and photoresist, while the reaction mechanism remains relatively simple and controlled.

Inventive Principle:

Principle #35Parameter changes

3Strength

If dehydration reaction is induced in the polarity conversion group, then adhesion with photoresist improves, but the process steps increase

Engineering Contradiction:

Improveadhesion strengthVSAvoidprocess steps

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The polarity conversion groups are pre-installed in the lower coating layer before the photo-lithography process. During exposure, these pre-positioned groups automatically undergo dehydration reaction to form hydrophobic regions, eliminating the need for separate adhesion-promoting process steps and maintaining process simplicity while enhancing adhesion strength.

Inventive Principle:

Principle #10Preliminary action

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 the resolution and stability of the photo-lithography process by improving the adhesion and chemical affinity between the photoresist and coating layers, allowing for precise pattern formation and preventing pattern misalignment or distortion during etching.

Implementation Method 1

a photoresist layer may be formed of a photoresist composition including a negative-tone photoresist polymer and a photoacid generator. A polarity of the exposed portion may be converted to be hydrophobic by an acid generated from the photoacid generator during the exposure process.

Methodology Applied

Scientific EffectPhotolysis: Photodissociation

Implementation Method 2

the acid may be diffused into the portion of the lower coating layer under the exposed portion to form the polarity conversion portion.

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

in transforming the portion of the lower coating layer, a dehydration reaction may be induced in the polarity conversion group by the acid diffused into the portion of the lower coating layer. The polarity conversion group may include a tertiary alcohol group, and a hydroxyl group included in the tertiary alcohol group may be replaced with a double bond.

Methodology Applied

Scientific EffectDehydration reaction:

Data Source

PatentUS9772555B2Methods of forming patterns using photoresists

Publication Date: 2017.09.26 SAMSUNG ELECTRONICS CO LTD

AI summary

In a method of forming a pattern, a lower coating layer and a photoresist layer are sequentially formed on an object layer. An exposure process may be performed such that the photoresist layer is divided into an exposed portion and a non-exposed portion. A portion of the lower coating layer overlapping or contacting the exposed portion is at least partially transformed into a polarity conversion portion that has a polarity substantially identical to that of the exposed portion. The non-exposed portion of the photoresist layer is selectively removed.