EUV Patterning Device Phase Tune Portion Shadowing

Solution Overview

Problem

The thickness of the absorbing portion in patterning devices for lithographic apparatuses using EUV radiation leads to complex 3-dimensional diffraction and shadowing effects, as well as non-telecentricity, which affects the performance of the apparatus in forming small features on substrates.

Innovation Solution

A patterning device with an absorber portion comprising multiple layers of different materials, where the first layer has a higher refractive index and absorption coefficient than the second layer, and a phase tune portion to induce a phase shift causing destructive interference between the radiation reflected by the reflector and absorber portions, reducing the absorber thickness to less than 25 nm and minimizing shadowing and non-telecentricity effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the absorber portion thickness is increased to improve absorption of EUV radiation, then the absorption performance is improved, but complex 3-dimensional diffraction and shadowing effects occur

Engineering Contradiction:

Improveabsorption performanceVSAvoidshadowing effects

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The absorber portion is segmented into multiple layers with different materials (e.g., Mo, Si, Ru, B4C) rather than using a single thick layer. This segmentation allows each layer to contribute differently to absorption and reflection, achieving sufficient absorption performance while reducing the overall thickness to minimize shadowing effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The absorber portion uses composite materials consisting of multiple layers with different optical properties. By combining materials with varying absorption coefficients and refractive indices, the design achieves effective EUV radiation absorption with reduced thickness, thereby minimizing shadowing and diffraction effects.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the absorber portion thickness is increased to improve absorption of EUV radiation, then the absorption performance is improved, but non-telecentricity effects occur

Engineering Contradiction:

Improveabsorption performanceVSAvoidnon-telecentricity effects

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The absorber portion is segmented into multiple layers with different materials (e.g., Mo, Si, Ru, B4C) rather than using a single thick layer. This segmentation allows each layer to contribute differently to absorption and reflection, achieving sufficient absorption performance while reducing the overall thickness to minimize shadowing effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The absorber portion uses composite materials consisting of multiple layers with different optical properties. By combining materials with varying absorption coefficients and refractive indices, the design achieves effective EUV radiation absorption with reduced thickness, thereby minimizing shadowing and diffraction effects.

Inventive Principle:

Principle #40Composite materials

3Object-generated harmful factors

If the absorber portion thickness is reduced to minimize shadowing effects, then shadowing and non-telecentricity effects are reduced, but absorption performance may deteriorate

Engineering Contradiction:

Improveshadowing effectsVSAvoidabsorption performance

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The absorber portion uses composite materials consisting of multiple layers with different optical properties. By combining materials with varying absorption coefficients and refractive indices, the design achieves effective EUV radiation absorption with reduced thickness, thereby minimizing shadowing and diffraction effects.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the optical parameters of the absorber portion by using materials with different absorption coefficients and refractive indices. This allows optimization of both thickness and absorption performance, achieving thin absorber layers that maintain high absorption efficiency while minimizing shadowing effects.

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If a single material is used in the absorber portion, then the structure is simple, but the reflectivity cannot be optimized and thickness must be increased

Engineering Contradiction:

Improvestructure complexityVSAvoidabsorption performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The absorber portion uses composite materials consisting of multiple layers with different optical properties. By combining materials with varying absorption coefficients and refractive indices, the design achieves effective EUV radiation absorption with reduced thickness, thereby minimizing shadowing and diffraction effects.

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

This configuration improves the performance of the lithographic apparatus by reducing shadowing and non-telecentricity effects, allowing for the formation of smaller features with improved precision and stability under EUV radiation.

Implementation Method 1

a phase tune portion arranged between the reflector portion and the absorber portion, the phase tune portion being configured to induce a phase shift between the radiation reflected by the reflector portion and the portion of radiation reflected by the absorber portion

Methodology Applied

Scientific EffectPhase shift: Phase Modulation

Implementation Method 2

the radiation reflected by the reflector portion destructively interferes with the portion of radiation reflected by the absorber portion

Methodology Applied

Scientific EffectDestructive interference: Interference

Implementation Method 3

an absorber portion configured to absorb incident radiation and to reflect a portion of incident radiation

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 4

a reflector portion arranged beneath the absorber portion, the reflector portion being configured to reflect incident radiation

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS10928735B2Patterning device

Publication Date: 2021.02.23 ASML NETHERLANDS BV

AI summary

A patterning device for use with a lithographic apparatus, the device comprising an absorber portion configured to absorb incident radiation and to reflect a portion of incident radiation, the absorber portion comprising a first layer and a second layer, the first layer of the absorber portion comprising a first material that is different from a second material of the second layer of the absorber portion; a reflector portion arranged beneath the absorber portion, the reflector portion being configured to reflect incident radiation; and a phase tune portion arranged between the reflector portion and the absorber portion, the phase tune portion being configured to induce a phase shift between the radiation reflected by the reflector portion and the portion of radiation reflected by the absorber portion such that the radiation reflected by the reflector portion destructively interferes with the portion of radiation reflected by the absorber portion.