Protective Photoresist Layer for Contamination-Resistant Patterning

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Solution Overview

Problem

As semiconductor devices shrink in size, the process windows for photolithographic processing become tighter, and defects from contaminants like particles, moisture, and ammonia in photoresist become more critical, necessitating advances in photolithographic processing to maintain device scaling and defect elimination.

Innovation Solution

A photoresist composition is used with a protective polymer layer that forms over the photoresist layer, preventing contaminants and enhancing chemical differences between exposed and unexposed regions through radiation exposure, followed by selective development and etching to transfer patterns into the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photoresist is used for photolithographic processing, then pattern formation is achieved, but contaminant absorption (particles, moisture, ammonia) causes defects

Engineering Contradiction:

Improvepattern formation precisionVSAvoidcontaminant absorption

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A protective polymer layer is applied over the photoresist layer to serve as an intermediary barrier. This protective layer prevents contaminants (particles, moisture, ammonia) from being absorbed by the photoresist while allowing the photolithographic process to proceed normally, thereby eliminating defects without compromising pattern formation precision

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective polymer layer is applied in advance before photolithographic processing to preemptively prevent contaminant absorption. By establishing this protective barrier beforehand, the photoresist is shielded from harmful contaminants during storage and processing, preventing defect formation before it occurs

Inventive Principle:

Principle #9Preliminary anti-action

2Productivity

If device size is reduced to increase device density, then more devices fit on wafer, but process windows become tighter and defects more critical

Engineering Contradiction:

Improvedevice densityVSAvoidprocess window tolerance

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The protective polymer layer acts as a mediator that decouples the relationship between device scaling and defect susceptibility. By providing this additional protective layer, the system can achieve higher device density with tighter process windows without the usual increase in defect rates, as the protective layer shields against contaminants that would otherwise cause failures at smaller dimensions

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If protective polymer layer is applied over photoresist, then contaminant absorption is prevented, but additional processing step is added

Engineering Contradiction:

Improvecontaminant absorption preventionVSAvoidprocessing steps

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protective polymer application is merged with the existing photoresist coating process. Both the photoresist and protective polymer are applied in sequence during the same coating operation, and both layers are baked together in a single post-exposure bake step, thereby minimizing the increase in processing complexity while maintaining effective contaminant prevention

Inventive Principle:

Principle #5Merging (Combining)

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

The protective polymer layer effectively prevents contaminant absorption and enhances pattern transfer fidelity, reducing defects and improving the ability to form precise patterns in smaller semiconductor devices.

Implementation Method 1

Defects may be formed by the absorption of contaminants, such as particles, moisture, and ammonia in a photoresist during processing

Methodology Applied

Scientific EffectAbsorption (physical): Absorption (physical)

Implementation Method 2

Such an exposure modifies the chemical and physical properties of the exposed regions of the photosensitive material

Methodology Applied

Scientific EffectPhotochemical effect: Photopolymerisation

Data Source

PatentUS12436458B2Photoresist composition and method of forming photoresist pattern

Publication Date: 2025.10.07 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of forming a photoresist pattern includes forming a protective layer over a photoresist layer formed on a substrate, and selectively exposing the protective layer and the photoresist layer to actinic radiation. The protective layer and the photoresist layer are developed to form a pattern in the photoresist layer, and the protective layer is removed. The protective layer includes a polymer having pendant fluorocarbon groups and pendant acid leaving groups.