Photodegradable Base Photoresist for Pattern Profile Contrast

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Solution Overview

Problem

Conventional photoresist layers with non-photodegradable bases exhibit poor acid and base distribution contrast, leading to lower pattern contrast and poor profile quality due to the inability to confine acid distribution effectively as feature sizes decrease in semiconductor manufacturing.

Innovation Solution

A photoresist material comprising a photodegradable base linked with functional groups having delocalizable pi electrons, which is photosensitive and depletes in exposed areas, enhancing acid and base distribution contrast, combined with a polymer, photoacid generator, quencher, and electron acceptor, to improve pattern profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a non-photodegradable base is used in conventional photoresist layers, then the photoresist maintains structural stability, but acid and base distribution contrast deteriorates leading to poor pattern profiles

Engineering Contradiction:

Improvestructural stabilityVSAvoidpattern profile quality

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameter of the base material from non-photodegradable to photodegradable, enabling it to undergo photo-induced chemical changes. This allows the base to participate actively in the patterning process by depleting in exposed areas, thereby improving acid and base distribution contrast while maintaining structural integrity through the photodegradation mechanism

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photoresist system combining a photodegradable base with a polymer matrix, photoacid generator, and other additives. This composite approach allows the photodegradable base to provide enhanced contrast and pattern definition while the polymer and other components maintain structural stability and processability

Inventive Principle:

Principle #40Composite materials

2Productivity

If feature sizes are decreased to increase functional density, then production efficiency improves, but acid distribution contrast and base distribution contrast deteriorate

Engineering Contradiction:

Improveproduction efficiencyVSAvoidacid and base distribution contrast

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

By changing the photodegradability parameter of the base material, the patent enhances the photoresist's ability to maintain sharp chemical contrasts at smaller feature sizes. The photodegradable base responds more effectively to exposure at reduced dimensions, preserving acid and base distribution contrast even as critical dimensions decrease, thereby enabling continued scaling while maintaining pattern fidelity

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional non-photodegradable bases are used, then photoresist formulation is simpler, but pattern contrast and resolution are reduced

Engineering Contradiction:

Improvephotoresist formulation complexityVSAvoidpattern contrast

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent modifies the chemical parameter of the base to be photodegradable, which enhances pattern contrast through photo-induced depletion in exposed areas. While this increases formulation complexity slightly, the improvement in pattern contrast and resolution is substantial, particularly for advanced node patterning where high contrast is critical for achieving desired pattern fidelity

Inventive Principle:

Principle #35Parameter changes

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 photodegradable base material provides improved acid and base distribution contrast, resulting in enhanced pattern profiles, resolution, and reduced iso/dense bias, leading to better critical dimension uniformity and circularity in semiconductor device fabrication.

Implementation Method 1

The photodegradable base comprises an amine linked with a functional group comprising substantially delocalizable pi electrons by a —C— group

Methodology Applied

Scientific EffectPhotodegradation: Photodissociation

Implementation Method 2

a photoacid generator

Methodology Applied

Scientific EffectPhotoacid generation: Photodissociation

Data Source

PatentUS8658344B2Patterning process and photoresist with a photodegradable base

Publication Date: 2014.02.25 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A resist material and methods using the resist material are disclosed herein. An exemplary method includes forming a resist layer over a substrate, wherein the resist layer includes a polymer, a photoacid generator, an electron acceptor, and a photodegradable base; performing an exposure process that exposes portions of the resist layer with radiation, wherein the photodegradable base is depleted in the exposed portions of the resist layer during the exposure process; and performing an developing process on the resist layer.