Patterning Process Parameter Estimation for Process Window Boundaries

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Solution Overview

Problem

The existing lithography processes face challenges in efficiently determining optimal processing parameters to maintain the process window, leading to potential defects in pattern formation due to variations in processing conditions.

Innovation Solution

A method is introduced that iteratively determines the value of processing parameters by comparing current and prior values of characteristics, using techniques such as interpolation and affine combinations, to maintain the process window and identify patterns at risk of defectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If iterative determination of processing parameter values is performed to maintain the process window, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:

Improveprocess window maintenanceVSAvoidparameter optimization time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary simulations and calculations to establish the relationship between processing parameters and process window characteristics before actual manufacturing. By pre-determining optimal parameter ranges and their effects on process window boundaries, the system reduces the need for extensive iterative adjustments during production, thus improving precision while minimizing time loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the measured process window characteristics are continuously compared against target values, and processing parameters are adjusted accordingly. This closed-loop control system enables rapid convergence to optimal parameters by using feedback from previous iterations to guide subsequent adjustments, resolving the contradiction between achieving high precision and minimizing iteration time.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If extensive simulations are performed to determine optimal processing parameters, then manufacturing precision is improved, but productivity decreases

Engineering Contradiction:

Improvepattern formation accuracyVSAvoidprocess development speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent segments the simulation process into multiple stages, starting with coarse-grained parameter exploration and progressively refining to fine-grained optimization. By dividing the extensive simulation into hierarchical levels of detail, the system identifies optimal parameters more efficiently without sacrificing the thoroughness needed for high manufacturing precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs parameter changes by transforming the simulation approach from exhaustive parameter scanning to targeted parameter adjustment based on preliminary results. By changing the simulation parameters dynamically and focusing computational resources on critical parameter ranges, the system achieves high precision outcomes with reduced overall simulation time and improved productivity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the process window is maintained through precise parameter control, then reliability of pattern formation is improved, but device complexity increases

Engineering Contradiction:

Improvepattern formation consistencyVSAvoidparameter control system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent develops a universal parameter control methodology that can be applied across different lithography processes and equipment types. By creating a multi-functional framework that handles various processing parameters (exposure dose, focus, illumination conditions) through a unified approach, the system improves pattern formation reliability without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements self-service mechanisms where the system automatically determines optimal processing parameters and adjusts them without requiring complex external control systems. The methodology enables the lithography process to self-regulate by using built-in feedback from process monitoring, thereby improving reliability while minimizing the need for additional complex control devices.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11126092B2Methods for determining an approximate value of a processing parameter at which a characteristic of the patterning process has a target value

Publication Date: 2021.09.21 ASML NETHERLANDS BV

AI summary

A method including: determining a value of a characteristic of a patterning process or a product thereof, at a current value of a processing parameter; determining whether a termination criterion is met by the value of the characteristic; if the termination criterion is not met, determining a new value of the processing parameter from the current value of the processing parameter and a prior value of the processing parameter, and setting the current value to the new value and repeating the determining steps; and if the termination criterion is met, providing the current value of the processing parameter as an approximation of a value of the processing parameter at which the characteristic has a target value.