SLM Illumination Control for Semiconductor Wafer Dynamic Range Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor wafer inspection methods face challenges in reducing dynamic range, leading to issues like ghosting, flaring, and ringing, which compromise inspection sensitivity and increase costs and throughput due to suboptimal illumination levels and sensitivity in saturated areas.
Innovation Solution
A system and method utilizing a spatial light modulator (SLM) to dynamically control illumination patterns on a semiconductor wafer, synchronizing pixel configurations with wafer patterns to adjust illumination levels across different regions, thereby reducing dynamic range and minimizing negative impacts from high dynamic range imagery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional saturation method is used to illuminate darker regions, then sensitivity in dark regions is improved, but saturation occurs in brighter regions reducing inspection sensitivity
Solution Approach 1:
The patent applies local quality by using a spatial light modulator to provide different illumination levels to different regions of the wafer. Bright regions receive reduced illumination to prevent saturation, while dark regions receive increased illumination to enhance defect detection sensitivity. This localized control of illumination quality resolves the contradiction by optimizing inspection sensitivity for each region's specific characteristics.
Solution Approach 2:
The patent employs dynamics by dynamically adjusting the illumination pattern in real-time as the wafer moves through the inspection system. The spatial light modulator continuously modifies which regions are illuminated and at what intensity, adapting to the moving wafer's pattern and ensuring optimal illumination conditions are maintained throughout the inspection process.
2Measurement precision
If multiple passes at different illumination levels are performed, then sensitivity in both bright and dark regions is improved, but wafer fabrication throughput is reduced
Solution Approach 1:
The patent implements continuity of useful action by performing illumination adjustment and defect detection simultaneously in a single continuous pass. The spatial light modulator maintains optimal illumination levels throughout the entire wafer inspection process, eliminating the need for multiple separate passes and thereby maintaining high throughput while achieving comprehensive inspection sensitivity.
Solution Approach 2:
The dynamic adjustment of illumination patterns allows the system to adapt to different wafer regions in real-time during a single pass, replacing the static multi-pass approach. This dynamic capability enables continuous optimization of illumination levels across the entire wafer surface without interrupting the inspection flow.
3Manufacturing precision
If global illumination is reduced below saturation levels, then saturation is avoided, but inspection sensitivity in all regions is compromised
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially selective illumination. Instead of uniformly reducing global illumination, the spatial light modulator selectively illuminates only those regions that require it, maintaining optimal illumination levels locally in each region while preventing saturation in bright areas. This localized approach preserves inspection sensitivity without compromising illumination level control.
4Measurement precision
If illumination is optimized for darker regions, then sensitivity in dark regions is improved, but flaring and ringing occur from brighter regions
Solution Approach 1:
The patent applies local quality by using the spatial light modulator to control illumination levels in bright regions, preventing over-illumination that causes flaring and ringing artifacts. Simultaneously, dark regions receive adequate illumination for sensitive defect detection. This localized illumination control eliminates harmful optical effects while maintaining inspection sensitivity.
Solution Approach 2:
The patent employs preliminary anti-action by preemptively reducing illumination in bright regions before it can cause flaring or ringing artifacts. The spatial light modulator is configured to limit the intensity of light reaching bright areas, preventing the generation of harmful optical effects before they occur, while still allowing adequate illumination for defect detection.
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
The solution effectively reduces dynamic range, enhancing defect detection sensitivity, eliminating ghosting and flaring, and optimizing illumination levels for improved wafer inspection, thus reducing costs and increasing throughput.
Implementation Method 1
a spatial light modulator (SLM) disposed along the illumination path and configured to receive at least a portion of light emanating from the illumination source
Implementation Method 2
a detector configured to detect light emanating from the surface of the wafer
Data Source
AI summary
The present invention includes generating illumination, providing a spatial light modulator (SLM) configured to selectably illuminate one or more portions of a surface of a wafer using the generated illumination, receiving a sets of wafer pattern data indicative of one or more patterns of the wafer, translating the wafer along a direction, selectably controlling a pixel configuration of the SLM to control an illumination pattern on the surface of the wafer, a first pixel configuration illuminating a first set of regions of the wafer at an illumination level, an additional pixel configuration illuminating an additional set of regions at an additional illumination level, wherein a pixel pattern of the SLM based on the received sets of wafer pattern data is configured to move across a surface of the SLM synchronously with the pattern of the translated wafer, and detecting illumination from the surface of the wafer.