Lithographic Illumination System Allocation Scheme

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Solution Overview

Problem

Existing lithographic apparatuses face limitations in efficiently modifying radiation beam properties and reducing intensity variations, leading to suboptimal pattern projection on substrates.

Innovation Solution

The use of an array of individually controllable elements with a specific allocation scheme to convert and direct radiation into desired illumination modes, allowing for precise control of radiation beam properties and minimizing movement requirements when switching between modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an array of individually controllable elements is used to convert radiation beam into desired illumination mode, then the ability to modify radiation beam properties is improved, but the device complexity increases

Engineering Contradiction:

Improveability to modify radiation beam propertiesVSAvoidcomplexity of illumination system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The illumination system is divided into an array of individually controllable elements (such as mirrors or lenslets), where each element can be independently adjusted to modify specific portions of the radiation beam. This segmentation enables precise control over illumination mode while maintaining manageable complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The individually controllable elements are made dynamically adjustable, allowing the system to switch between different illumination modes (e.g., from uniform to annular, or between different numerical apertures) by reconfiguring the elements in real-time, providing adaptability without requiring multiple fixed systems

Inventive Principle:

Principle #15Dynamics

2Device complexity

If a random allocation scheme is used to allocate elements to illumination mode parts, then the device complexity is reduced, but the productivity decreases due to excessive movement requirements

Engineering Contradiction:

Improvesimplicity of allocation schemeVSAvoidefficiency of mode switching

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

An optimized allocation scheme is pre-established that assigns specific elements to specific regions of the illumination mode based on their initial positions and characteristics. When switching between modes, this pre-planned allocation minimizes the movement distance each element must travel, thereby maintaining high productivity without complex real-time calculations

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If elements are moved extensively to switch between illumination modes, then the adaptability is improved, but the loss of time increases

Engineering Contradiction:

Improveability to switch between modesVSAvoidtime required for mode switching

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

Different regions of the element array are assigned to control different parts of the illumination mode based on local optimization principles. Elements that need to work together for a particular mode are grouped in specific spatial arrangements, reducing the distance they need to move when switching modes and thereby minimizing time loss while maintaining adaptability

Inventive Principle:

Principle #3Local quality

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 enhances the accuracy and efficiency of pattern projection by optimizing radiation beam properties and reducing the need for excessive movement of elements, thereby improving lithography processes.

Implementation Method 1

an array of individually controllable elements and associated optical components arranged to convert the radiation beam into a desired illumination mode

Methodology Applied

Scientific EffectOptical components:

Implementation Method 2

using a patterning device to impart the radiation beam having the desired illumination mode with a pattern in its cross-section

Methodology Applied

Scientific EffectPattern projection:

Implementation Method 3

projecting the patterned radiation beam onto a target portion of the substrate

Methodology Applied

Scientific EffectBeam projection:

Data Source

PatentUS10222703B2Lithographic apparatus and method

Publication Date: 2019.03.05 ASML NETHERLANDS BV

AI summary

A device manufacturing method includes conditioning a beam of radiation using an illumination system. The conditioning includes controlling an array of individually controllable elements and associated optical components of the illumination system to convert the radiation beam into a desired illumination mode, the controlling including allocating different individually controllable elements to different parts of the illumination mode in accordance with an allocation scheme, the allocation scheme selected to provide a desired modification of one or more properties of the illumination mode, the radiation beam or both. The method also includes patterning the radiation beam having the desired illumination mode with a pattern in its cross-section to form a patterned beam of radiation, and projecting the patterned radiation beam onto a target portion of a substrate.