Scanning System Counter-Scan Beam Static Focal Point
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Solution Overview
Problem
Current scanning systems for semiconductor wafers face challenges in achieving high throughput and maintaining data quality due to limitations in scanning technology, particularly in efficiently managing radiation beams and detecting radiation across elongated spots.
Innovation Solution
A scanning system comprising an illumination module that scans an elongated radiation spot over an object and a collection module that optically manipulates the collected radiation beam to provide a counter-scan beam directed towards detection units, with a focal point remaining static regardless of the spot's propagation, allowing multiple spots to be scanned simultaneously and increasing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional scanning system uses a single detection unit to collect radiation from an elongated spot, then the system is simpler in structure, but the throughput is limited and data quality suffers due to sequential scanning requirements
Solution Approach 1:
The detection system is segmented into multiple detection units arranged in a column, where each detection unit corresponds to a specific portion of the elongated radiation spot. This segmentation allows parallel collection of radiation data from different spatial locations simultaneously, thereby increasing scanning throughput without requiring complex mechanical scanning mechanisms for the detectors
Solution Approach 2:
The set of detection units serves multiple functions: (1) simultaneously collecting radiation from different portions of the elongated spot, (2) maintaining a static focal point for the counter-scan beam, and (3) enabling parallel processing of multiple spots. This multi-functionality achieves high throughput while avoiding the need for additional complex scanning components
2Reliability
If the focal point of the counter-scan beam moves during scanning, then the optical system is simpler, but artifacts are introduced and data quality deteriorates
Solution Approach 1:
The optical system is pre-configured with the detection units positioned at locations that correspond to the elongated spot geometry, and the counter-scan beam is optically manipulated to maintain a static focal point at the detection units. This preliminary configuration ensures that as the illumination spot scans across the object, the detected radiation always focuses at the correct spatial locations without requiring dynamic adjustment during scanning, thereby maintaining data quality
Solution Approach 2:
Different detection units are positioned to receive radiation from specific local portions of the elongated spot. Each detection unit has a dedicated field of view that matches the spot width, creating a one-to-one correspondence between spot position and detector position. This local quality mapping ensures accurate spatial registration of detected radiation without introducing artifacts
3Productivity
If multiple elongated radiation spots are scanned simultaneously, then throughput increases, but the optical system complexity increases significantly
Solution Approach 1:
Multiple elongated radiation spots are merged into a single illumination beam path by scanning the beam across multiple locations on the object simultaneously. The collection module merges the radiation from multiple spots into a single counter-scan beam that is directed to the detection units. This merging approach allows parallel scanning of multiple spots without requiring separate illumination and detection paths for each spot, thereby increasing throughput while limiting optical complexity
4Measurement precision
If the field of view of detection units does not match the spot width, then the optical alignment is simpler, but measurement precision and defect detection capability are reduced
Solution Approach 1:
The field of view parameter of each detection unit is specifically designed to match the width of the elongated radiation spot. This parameter matching ensures that each detection unit captures radiation from the complete width of the spot at its corresponding position, maximizing the signal-to-noise ratio and enabling precise defect detection. The systematic parameter matching across all detection units creates a unified measurement system with consistent precision
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 enhances scanning throughput and reduces artifacts by maintaining a static focal point for counter-scan beams, improving data quality and enabling efficient detection across multiple elongated radiation spots.
Implementation Method 1
a collection module that may be configured to (a) collect a collected radiation beam from the object, and (b) optically manipulate the collected radiation beam to provide a counter-scan beam
Data Source
AI summary
A scanning system that includes an illumination module that is configured to scan, at a first direction, an elongated radiation spot over an object; and a collection module that is configured to (a) collect a collected radiation beam from the object, and (b) optically manipulate the collected radiation beam to provide a counter-scan beam is directed towards a set of detection units and has a focal point that is positioned at a same location regardless of the propagation of the elongated radiation spot along the first direction.