Rotatable EUV Optical Reflector for Lithography Energy Loss

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Solution Overview

Problem

The increasing complexity of processing semiconductor devices with decreased feature sizes in integrated circuits poses challenges in achieving high-density IC formation, particularly in maintaining efficient lithography processes for precise pattern formation and minimizing energy loss and contamination in extreme ultraviolet (EUV) exposure tools.

Innovation Solution

The implementation of a lithography system that includes a collector with a multilayer reflector, a laser generator, a droplet generator, and rotatable optical reflectors, which synchronize EUV light generation and reflection to pattern a photoresist layer on a wafer, allowing for controlled exposure and rotation of optical reflectors to prevent energy loss and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If optical reflectors are used to reflect EUV light in lithography, then pattern formation precision is improved, but energy loss and contamination on the reflectors occur

Engineering Contradiction:

Improvepattern formation precisionVSAvoidEUV light energy loss

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The optical reflectors are made rotatable rather than fixed, allowing them to be dynamically repositioned between different operational states. This enables the system to rotate reflectors out of the EUV light path when not needed, preventing energy loss and contamination while maintaining pattern formation precision when reflectors are actively used.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements a multi-reflector configuration where used reflectors can be rotated out of service and replaced with fresh ones. This allows contaminated or energy-depleted reflectors to be discarded (rotated away) while clean reflectors are brought into use, maintaining optimal performance without permanent degradation.

Inventive Principle:

Principle #34Discarding and recovering

2Reliability

If optical reflectors are rotated to prevent contamination, then energy loss and contamination are reduced, but system complexity increases

Engineering Contradiction:

Improvereflector cleanlinessVSAvoidlithography system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The single reflector is segmented into multiple separate reflector elements that can be independently rotated and positioned. This segmentation allows the system to manage contamination and energy loss by isolating individual reflectors, while the modular nature keeps overall system complexity manageable through standardized components.

Inventive Principle:

Principle #1Segmentation

3Productivity

If more aggressive design rules are implemented to increase IC density, then manufacturing throughput is improved, but processing complexity increases

Engineering Contradiction:

ImproveIC manufacturing densityVSAvoidprocessing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system changes the operational parameters of the lithography tool by implementing variable reflector rotation angles and positions. This allows optimization of EUV light delivery for different pattern densities and feature sizes, enabling more aggressive IC design rules to be manufactured while managing processing complexity through adaptive parameter control.

Inventive Principle:

Principle #35Parameter changes

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 throughput and yield of the EUV process by preventing energy loss and reducing contamination on optical reflectors, while allowing for flexible exposure patterns, thereby improving the precision and efficiency of semiconductor device manufacturing.

Implementation Method 1

a laser generator configured to generate a laser beam

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

configured to generate extreme ultraviolet (EUV) light in response to the laser emission operation and the droplet shooting operation

Methodology Applied

Scientific EffectEUV light generation:

Implementation Method 3

A collector is used to gather the EUV light onto a first optical reflector

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 4

The first optical reflector is used to reflect the EUV light to a reticle, so as to impart the EUV light with a pattern. A second optical reflector is used to reflect the EUV light with the pattern onto a wafer

Methodology Applied

Scientific EffectOptical reflection: Reflection

Data Source

PatentUS11016390B2Method for exposing wafer

Publication Date: 2021.05.25 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method includes generating extreme ultraviolet (EUV) light. The EUV light is gathered onto a first region of a first optical reflector by using a collector. A second region of the first optical reflector is free from incidence of the EUV light when the EUV light is reflected onto the first region. The EUV light is reflected to a reticle by using the first optical reflector, so as to impart the EUV light with a pattern. The first optical reflector is rotated such that the EUV light is reflected onto the second region in a first time period and the EUV light is reflected onto the first region in a second period. The first region is free from incidence of the EUV light in the first time period, and the second region is free from incidence of the EUV light in the second time period.