Optical Element Configuration for Wafer Inspection
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Solution Overview
Problem
Current wafer inspection systems face challenges in efficiently determining optimal configurations for optical elements in collection and illumination apertures, particularly due to the need to consider numerous parameter combinations for different types of wafers and defects, leading to complex and time-consuming recipe setup processes.
Innovation Solution
A system and method that uses a light source, optical elements with adjustable apertures, and a computer subsystem to generate and compare images from different optical configurations, reconstructing additional images and selecting the optimal configuration for enhanced defect detection and noise reduction by analyzing image characteristics and phase relations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple parameter combinations are considered for different types of wafers and defects, then detection accuracy is improved, but setup complexity and time consumption increase
Solution Approach 1:
The system performs preliminary evaluation of multiple optical parameter combinations automatically before final recipe creation. The computer subsystem evaluates different aperture configurations, illumination wavelengths, and polarization states in advance, selecting optimal combinations without requiring manual setup for each parameter variation.
Solution Approach 2:
The system creates virtual models or simulations of different optical configurations to evaluate their performance before physical implementation. By copying and testing parameter combinations in silico, the system identifies optimal settings without requiring extensive physical setup and measurement iterations.
2Measurement precision
If multiple parameter combinations are evaluated, then detection accuracy is improved, but time consumption increases
Solution Approach 1:
The system performs preliminary evaluation of multiple optical parameter combinations automatically before final recipe creation. The computer subsystem evaluates different aperture configurations, illumination wavelengths, and polarization states in advance, selecting optimal combinations without requiring manual setup for each parameter variation.
Solution Approach 2:
The system replaces manual mechanical adjustment and evaluation of optical parameters with automated computer-controlled adjustment and algorithmic evaluation. The computer subsystem automatically varies optical parameters, captures images, and evaluates detection performance, eliminating time-consuming manual operations.
3Measurement precision
If optical element configuration is optimized for specific defect types, then defect detection capability is improved, but system versatility decreases
Solution Approach 1:
The system employs dynamic, adjustable optical elements that can be reconfigured for different inspection scenarios. The optical elements include adjustable apertures, variable wavelength illumination, and switchable polarization states, allowing the system to adapt its configuration based on the specific defect types and wafer characteristics being inspected.
Solution Approach 2:
The system optimizes detection capability by dynamically changing optical parameters such as aperture size, illumination wavelength, and polarization angle based on the inspection requirements. The computer subsystem automatically adjusts these parameters to match the specific defect characteristics, achieving high detection accuracy while maintaining versatility across different defect types.
Data Source
AI summary
Methods and systems for determining a configuration for an optical element positioned in a collection aperture during wafer inspection are provided. One system includes a detector configured to detect light from a wafer that passes through an optical element, which includes a set of collection apertures, when the optical element has different configurations thereby generating different images for the different configurations. The system also includes a computer subsystem configured for constructing additional image(s) from two or more of the different images, and the two or more different images used to generate any one of the additional image(s) do not include only different images generated for single collection apertures in the set. The computer subsystem is further configured for selecting one of the different or additional configurations for the optical element based on the different images and the additional image(s).