Positive Resist Composition for High-Fidelity Sub-100 nm Pattern Formation

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Solution Overview

Problem

Conventional resist compositions face challenges in reproducing fine patterns with high fidelity and accuracy, particularly in miniaturization processes, due to issues like pattern collapse and deteriorated circularity in hole patterns with diameters less than 100 nm, resulting from mask error factors and limitations in lithography properties such as resolution and sensitivity.

Innovation Solution

A positive resist composition incorporating a polymeric compound with specific structural units that exhibit increased solubility in alkali developing solutions upon acid exposure, allowing for precise pattern formation by adjusting the proportions of structural units (a0-1, a0-2, and a1-0-1) within the polymeric compound, enhancing the resist's ability to maintain pattern integrity and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional resist compositions are used for miniaturization processes, then lithography can be performed with standard materials, but pattern fidelity deteriorates and mask error factors increase for fine patterns

Engineering Contradiction:
Improvepattern fidelityVSAvoidmask error factor
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the resist material by incorporating specific polymeric compounds with controlled structural unit proportions (a0-1: 10-40 mol%, a0-2: 5-20 mol%, a1-0-1: 10-55 mol%). This changes the solubility characteristics and acid-base properties of the resist, enabling better pattern fidelity and reduced mask error factors in miniaturization processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resist composition by combining multiple polymeric compounds with specific functional groups (carboxyl, hydroxyl, lactone structures) and acid-dissociable dissolution-inhibiting groups. This composite approach synergistically improves both pattern fidelity and reduces mask error factors that cannot be achieved with single-component resists.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If the wavelength of exposure light is shortened to achieve pattern miniaturization, then resolution improves, but sensitivity and lithography properties deteriorate

Engineering Contradiction:
ImproveresolutionVSAvoidsensitivity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent adjusts the chemical parameters of the resist by incorporating polymeric compounds with specific functional groups that enhance sensitivity to shorter wavelength exposure light. The carboxyl, hydroxyl, and lactone structures modify the photochemical response, maintaining high sensitivity while achieving improved resolution with KrF and ArF excimer lasers.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If hole patterns with diameters less than 100 nm are formed, then pattern miniaturization is achieved, but circularity deteriorates and pattern collapse occurs

Engineering Contradiction:
Improvepattern dimensionVSAvoidcircularity
Core Design Contradiction:
Length of moving objectVSShape

Solution Approach 1:

The patent modifies the physical and chemical parameters of the resist material through specific polymeric compound composition, controlling solubility and mechanical properties. This enables maintenance of circularity and prevention of pattern collapse even when forming hole patterns with diameters less than 100 nm.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite resist composition with multiple polymeric compounds provides synergistic effects that simultaneously achieve miniaturization while maintaining pattern shape integrity. The combination of different functional groups creates a resist with optimized mechanical strength and solubility characteristics for sub-100 nm hole pattern formation.

Inventive Principle:
Principle #40Composite materials

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 proposed resist composition effectively improves pattern fidelity and resolution, reducing mask error factors and pattern collapse, enabling the formation of precise, high-resolution resist patterns with improved circularity and uniformity, especially in the formation of fine features.

Implementation Method 1

an acid generator that generates acid upon exposure

Methodology Applied
Scientific EffectPhotoacid generation: Photo-oxidation

Implementation Method 2

selective exposure of radial rays such as light or electron beam through a mask having a predetermined pattern

Methodology Applied
Scientific EffectRadiation absorption: Absorption (EM radiation)

Data Source

PatentUS8232041B2Positive resist composition, method of forming resist pattern, and polymeric compound
Publication Date: 2012.07.31 TOKYO OHKA KOGYO CO LTD

AI summary

A polymeric compound (A1) includes a structural unit (a0-1) represented by general formula (a0-1), a structural unit (a0-2) represented by general formula (a0-2), and a structural unit (a1-0-1) represented by general formula (a1-0-1), wherein relative to the combined total of all the structural units, the proportion of the structural unit (a0-1) is from 10 to 40 mol %, the proportion of the structural unit (a0-2) is from 5 to 20 mol %, and the proportion of the structural unit (a1-0-1) is from 10 to 55 mol %. [In the formulas, each of R1 and R independently represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, or a halogenated alkyl group of 1 to 5 carbon atoms, R2, A and B each represents a divalent linking group, R3 represents a cyclic group containing —SO2— within the ring skeleton thereof, and R4 and X1 each represents an acid-dissociable, dissolution-inhibiting group.]