Lithography Defectivity Quantification Using Off-Target Parameters

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Solution Overview

Problem

Existing methods for determining defectivity quantifiers in lithographical circuit fabrication processes are resource-intensive and time-consuming due to the low occurrence rates of stochastic-induced defects at optimal process conditions, making it challenging to accurately assess and calibrate lithographic stochastic models within modern IC design timeframes.

Innovation Solution

A defectivity quantifier technology that determines defectivity quantifiers through off-target process parameters, allowing for the determination of stochastic-induced defects and effects at increased rates, thereby reducing the need for extensive computational or physical resources by simulating or fabricating at target conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional lithography processes are used, then manufacturing cost is reduced, but manufacturing precision deteriorates due to inability to print sub-10 nanometer features

Engineering Contradiction:
Improvefeature size precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the wavelength parameter of light from conventional visible/near-UV ranges to extreme ultraviolet (EUV) range (13.5 nanometers), enabling sub-10 nanometer feature printing. This parameter change allows conventional lithography to achieve the required manufacturing precision for next-generation integrated circuits while maintaining compatibility with existing lithography tool architectures.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If EUV lithography is implemented to achieve sub-10 nanometer printing, then manufacturing precision is improved, but device complexity increases due to new light sources and optics

Engineering Contradiction:
Improvefeature size precisionVSAvoidlithography system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical mirrors with reflective optics designed specifically for EUV wavelengths. The system uses a series of reflective elements including a zone plate and cylindrical mirrors that are optimized for 13.5 nanometer light, eliminating the need for conventional refractive lenses and simplifying the optical path while achieving the required precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a zone plate as an intermediary optical element that converts the EUV light from the source into a focused beam pattern suitable for lithography. This zone plate acts as a mediator between the high-energy EUV source and the subsequent optical elements, enabling efficient energy transfer and precise beam control.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If process parameters are tightly controlled to maintain manufacturing precision, then manufacturing precision is improved, but productivity decreases due to reduced process window

Engineering Contradiction:
Improvefeature size precisionVSAvoidproduction throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements dynamic control of the illumination system, allowing real-time adjustment of the light source parameters and optical element positions. This dynamic capability enables the system to adapt to varying process conditions and maintain optimal focus and exposure across different production scenarios, effectively expanding the usable process window.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback mechanisms that monitor the actual lithography process parameters and adjust the illumination and optical systems accordingly. This closed-loop control ensures that manufacturing precision is maintained while allowing greater flexibility in process parameter selection, thereby improving productivity without sacrificing quality.

Inventive Principle:
Principle #23Feedback

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

Enables efficient and resource-effective determination of defectivity quantifiers for lithographical circuit fabrication processes, facilitating faster and more accurate assessment of lithographic processes without the need for billions of simulations or fabrications at optimal conditions.

Implementation Method 1

an illumination system adapted to receive light from the light source and focus the light onto the photomask

Methodology Applied
Scientific EffectLight focusing: Focusing

Implementation Method 2

a photomask adapted to receive focused light from the illumination system and generate a pattern corresponding to features of an integrated circuit

Methodology Applied
Scientific EffectOptical absorption and transmission: Absorption (EM radiation)

Data Source

PatentEP4374225B1Defectivity quantifier determinations for lithographical circuit fabrication processes through off-target process parameters
Publication Date: 2026.05.06 SIEMENS INDUSTRY SOFTWARE INC
  • EP4374225B1 patent drawingFigure 1
  • EP4374225B1 patent drawingFigure 2
  • EP4374225B1 patent drawingFigure 3

AI summary

A computing system (100) may include a quantifier determination engine (110) configured to determine a defectivity quantifier (310) for a lithographical circuit fabrication process performed with a target value (210) for a process parameter, including by modifying the target value (210) to obtain an off-target value (220) for the process parameter, determining a defectivity quantifier (250) for the lithographical circuit fabrication process performed with the off-target value (220), and extrapolating the defectivity quantifier (310) for the lithographical circuit fabrication process performed with the target value (210) from the determined defectivity quantifier (250) for the lithographical circuit fabrication process performed with the off-target value (220). The computing system (100) may also include a quantifier provision engine (112) configured to provide the determined defectivity quantifier (310) for assessment of the lithographical circuit fabrication process.