Segmented Beam Influencing Element for Microlithography

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Solution Overview

Problem

Conventional microlithographic projection exposure apparatuses face limitations in rapidly switching between illumination settings without significant light loss, particularly when adjusting for different mask exposures in short intervals, due to the mechanical constraints of adjustable optical components.

Innovation Solution

The implementation of an optical beam influencing element divided into multiple beam influencing regions, allowing for independent generation of various illumination modes without attenuation, which can be quickly reconfigured by displacing the element perpendicular to its long side, enabling rapid switching between illumination settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional adjustable optical components are used to switch between illumination settings, then illumination mode variety is achieved, but switching time increases and light loss occurs due to mechanical travel distances

Engineering Contradiction:

Improveillumination mode varietyVSAvoidswitching time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The illumination system is segmented into multiple independently controllable optical elements (stop, phase, amplitude) that can be individually adjusted. This allows different illumination modes to be generated by combining different segments rather than moving entire optical components, enabling rapid switching without mechanical travel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs dynamically adjustable optical elements with variable transmission and phase characteristics. These elements can be rapidly reconfigured through electronic control to switch between illumination modes instantaneously, eliminating the mechanical inertia and travel time associated with conventional adjustable components.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If conventional adjustable optical components are used to switch between illumination settings, then illumination mode variety is achieved, but light loss increases due to mechanical constraints and component movement

Engineering Contradiction:

Improveillumination mode varietyVSAvoidlight loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent replaces mechanical optical components (movable mirrors, rotatable filters) with electronically controlled optical elements. These electronic components adjust illumination characteristics without physical movement, eliminating light loss from mechanical constraints and component alignment issues during switching.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical elements are designed with variable transmission and phase parameters that can be electronically adjusted. By changing these parameters rather than moving components, the system achieves illumination mode switching without the light loss associated with mechanical movement and realignment.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If exchangeable pupil filters are used for illumination switching, then illumination mode variety is achieved, but light loss increases and switching speed decreases

Engineering Contradiction:

Improveillumination mode varietyVSAvoidswitching speed

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

Instead of static exchangeable filters, the patent employs dynamic optical elements with continuously adjustable transmission and phase characteristics. These elements can be rapidly reconfigured through electronic control to switch between illumination modes instantaneously, eliminating the mechanical inertia and travel time associated with conventional adjustable components.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent replaces mechanical filter exchange mechanisms with electronically controlled optical modulators. These electronic components enable illumination switching without physical movement, eliminating light loss from mechanical constraints and achieving much faster switching speeds.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution enables rapid and efficient switching between illumination settings within fractions of a second with minimal light loss, enhancing the flexibility and performance of microlithographic projection exposure apparatuses by allowing precise control over illumination modes and intensity distributions.

Implementation Method 1

The generation of various illumination modes for the object field using the at least two beam influencing regions of the optical beam influencing element may be independent of a light attenuation. This is achievable by a diffractive, refractive or reflective generation in the beam influencing regions.

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS7787104B2Illumination optics for a microlithographic projection exposure apparatus

Publication Date: 2010.08.31 CARL ZEISS SMT GMBH

AI summary

Illumination optics for a microlithographic projection exposure apparatus is used for illumination of an object field in the object plane with illumination light of a radiation source. The illumination optics has an optical beam influencing element which is divided into at least two beam influencing regions in order to generate various illumination modes for the object field which are independent of a light attenuation. The optical beam influencing element is displaceable between a first beam influencing position where a first one of the beam influencing regions is exposed to a bundle of the illumination light, and at least another beam influencing position where another one of the beam influencing regions is exposed to the bundle of the illumination light. Each of the beam influencing regions has a surface which is exposable to illumination light and has a long and a short side length, with the optical beam influencing element being displaceable perpendicular to the long side length. The result is an illumination optics which allows rapid switching between various illumination settings, preferably within fractions of a second and substantially without light loss.