Wafer Inspection Parameter Selection via Optical Mode Scoring

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Solution Overview

Problem

Current wafer inspection processes are labor-intensive and time-consuming due to the need for manual setup and optimization of multiple optical modes and defect detection parameters, often resulting in sub-optimal inspection outcomes due to limited time and capability for exploring combinations of optical modes and sensitivity parameter tuning.

Innovation Solution

A computer-implemented method and system for selecting one or more parameters for wafer inspection, which includes acquiring output from individual optical modes, determining capture rates of defects of interest and nuisance defects, calculating scores for these modes, and selecting the optimal optical modes or combinations for inspection based on these scores, allowing for simultaneous tuning of defect detection parameters across multiple scans.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual processes are used to set up inspection processes for each wafer type, then flexibility to handle different wafer types is achieved, but the setup time becomes prohibitively long

Engineering Contradiction:

Improveflexibility to handle different wafer typesVSAvoidsetup time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs self-service by automatically selecting optimal optical modes and sensitivity parameters for inspection processes. The computer system autonomously evaluates multiple optical modes, determines capture rates for defects of interest and nuisance defects, calculates scores, and selects the best configuration without requiring manual setup for each wafer type, thereby eliminating the time-consuming manual configuration while maintaining adaptability to different wafer types

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system utilizes parameter changes by automatically adjusting optical modes and sensitivity parameters based on the specific wafer type and defect characteristics. The computer system evaluates different parameter combinations (optical modes, aperture, focus offset, polarization, angles of collection) and selects the optimal set of parameters for each inspection scenario, enabling rapid adaptation to different wafer types without manual intervention

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a large number of adjustable output acquisition settings and sensitivity parameters are available in the inspection system, then the ability to detect different types of defects is improved, but the difficulty of setting up the inspection process increases

Engineering Contradiction:

Improveability to detect different types of defectsVSAvoiddifficulty of setting up inspection process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system implements feedback by using capture rate information to guide the selection of optical modes and sensitivity parameters. The computer system determines capture rates for defects of interest and nuisance defects for each optical mode, uses this feedback information to calculate scores, and selects the optimal configuration based on this feedback, thereby simplifying the setup process while maintaining the ability to detect different defect types

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The computer system acts as an intermediary between the complex inspection system capabilities and the user. It automatically processes the evaluation of multiple optical modes and parameters, determining capture rates and calculating scores to select the optimal configuration, thereby mediating the complexity of multiple adjustable parameters and presenting a simplified setup process to users

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of time

If incorrect or non-optimized output acquisition and sensitivity parameters are used, then the inspection process can be set up quickly, but the detection capability for defects of interest is lost due to high noise levels

Engineering Contradiction:

Improveinspection setup timeVSAvoiddefect detection capability

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by automatically selecting optimal optical modes and sensitivity parameters before the actual inspection process begins. The computer system evaluates multiple optical modes, determines capture rates, calculates scores, and selects the best configuration in advance, ensuring that the inspection process is both quick to set up and optimized for defect detection, eliminating the trade-off between speed and precision

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9601393B2Selecting one or more parameters for inspection of a wafer

Publication Date: 2017.03.21 KLA CORP

AI summary

Computer-implemented methods, computer-readable media, and systems for selecting one or more parameters for inspection of a wafer are provided.