Silicon Hardmask for Directed Self-Assembly Patterning

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Solution Overview

Problem

Current directed self-assembly (DSA) processes for microelectronic structure fabrication require multiple layers, including a neutral brush layer and anti-reflective coating, which increase complexity, time, and cost, and complicate chemical matching between layers.

Innovation Solution

A method that eliminates the need for a separate neutral brush layer and anti-reflective coating by applying the DSA layer directly on top of the hardmask, using a spin-applied silicon-containing hardmask layer with compatible moieties that induce pattern formation during self-assembly, and a carbon-rich intermediate layer to facilitate the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple layers (neutral brush layer, anti-reflective coating, hardmask) are used in DSA process, then pattern formation capability is improved, but process complexity and manufacturing time increase

Engineering Contradiction:
Improvepattern formation capabilityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the neutral brush layer and hardmask into a single integrated layer. The silicon-containing polymer provides both the neutral surface properties needed for DSA pattern formation and the hardmask functionality for etch resistance, eliminating the need for separate layers while maintaining both functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The silicon-containing polymer layer serves multiple functions simultaneously: it acts as a neutral layer to induce perpendicular pattern formation, provides hardmask properties for etch resistance, and eliminates the need for separate anti-reflective coating. This multi-functional approach reduces process complexity while maintaining pattern formation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple layers (neutral brush layer, anti-reflective coating, hardmask) are used in DSA process, then pattern formation capability is improved, but processing time and cost increase

Engineering Contradiction:
Improvepattern formation capabilityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

By merging the neutral brush layer and hardmask into a single layer, the patent reduces the number of deposition and processing steps required. This integration eliminates redundant processing time associated with applying and treating separate layers, while maintaining the pattern formation capability through the silicon-containing polymer's dual functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If conventional optical lithography is used, then process simplicity is maintained, but resolution limit is 37 nm for dense lines and spaces

Engineering Contradiction:
Improveprocess simplicityVSAvoidresolution
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The silicon-containing polymer layer acts as an intermediary that enables DSA pattern formation directly on the hardmask surface. This intermediary layer provides the necessary neutral surface properties to induce perpendicular pattern formation, allowing resolution beyond conventional lithography limits while simplifying the overall process by eliminating additional layers.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If separate neutral brush layer is used underneath block copolymer, then pattern formation is induced perpendicular to substrate, but chemical matching challenges between layers increase

Engineering Contradiction:
Improvepattern formation orientationVSAvoidchemical matching complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the neutral brush layer and hardmask into a single silicon-containing polymer layer, eliminating the chemical matching interface between separate organic brush layer and inorganic hardmask. The integrated layer provides both neutral surface properties for perpendicular pattern formation and compatible chemical properties for etch resistance, reducing chemical matching challenges.

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

This approach simplifies the DSA process, reduces processing time and cost, and achieves high-resolution pattern formation with improved chemical compatibility and etch resistance, enabling the formation of nanometer-scale features not achievable with conventional optical lithography.

Implementation Method 1

directed self-assembly (DSA), is already capable of forming patterns

Methodology Applied
Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 2

A carbon-rich intermediate layer is formed on the substrate or on the hardmask layer

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

A spin-applied silicon-containing hardmask layer is formed on a substrate or on a carbon-rich intermediate layer

Methodology Applied
Scientific EffectSpin coating: Spin Coating

Data Source

PatentEP2839341B1Method for directed self-assembly
Publication Date: 2020.01.15 BREWER SCIENCE INC
  • EP2839341B1 patent drawingFigure 1
  • EP2839341B1 patent drawingFigure 2(A)~2(C)
  • EP2839341B1 patent drawingFigure 3(A)~3(C)

AI summary

Compositions for directed self-assembly patterning techniques are provided which avoid the need for separate anti-reflective coatings and brush neutral layers in the process. Methods for directed self-assembly are also provided in which a self-assembling material, such as a directed self-assembly block copolymer, can be applied directly to the silicon hardmask neutral layer and then self-assembled to form the desired pattern. Directed self-assembly patterned structures are also disclosed herein.