Miniaturized Structure Processing End Point Detection
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Solution Overview
Problem
Current methods for detecting the end point of material deposition or removal in miniaturized structure processing, such as mask repair in the semiconductor industry, face challenges due to noisy detector signals and the inability to apply spatial frequency filtering, which can lead to overetching or overdoping, affecting the quality of the processed masks.
Innovation Solution
The method involves dividing the object region into surface segments of similar areas, integrating signals from each segment to form a total signal, and varying beam parameters for detection, allowing for precise end point determination by reducing noise and accounting for material variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detector signals are used for end point detection during material deposition or removal, then the processing end point can be monitored, but the signals are noisy and require noise suppression which complicates the detection system
Solution Approach 1:
The detector signal is segmented into multiple components based on different detection modes (secondary electron detection, backscattered electron detection, X-ray detection). Each segment serves a specific function in end point detection, allowing the system to process different signal types separately and reduce overall complexity while improving measurement precision
Solution Approach 2:
A signal processing unit acts as an intermediary between the detector and the control system. This intermediary processes the noisy detector signals through filtering and integration algorithms, suppressing noise while preserving the end point detection capability, thereby reducing the complexity of the overall detection system
2Measurement precision
If spatial frequency filtering is applied to suppress noise in detector signals, then noise is reduced, but this method cannot be applied in repairing defects which limits its usefulness
Solution Approach 1:
The detection system applies different processing strategies to different spatial regions. For periodic structures, spatial frequency filtering is applied to suppress noise. For defect regions, alternative noise suppression methods are used that do not rely on spatial periodicity. This local adaptation allows the system to maintain versatility while improving measurement precision in each specific context
3Manufacturing precision
If the electron beam is used to induce chemical reactions for material deposition or removal, then precise processing of miniaturized structures is achieved, but it becomes difficult to determine the correct end point without overprocessing
Solution Approach 1:
The system implements real-time feedback by continuously monitoring detector signals during electron beam processing. When the signal indicates that the end point has been reached (through characteristic changes in secondary electron yield, backscattered electron signal, or X-ray emission), the processing is automatically terminated. This feedback mechanism ensures both manufacturing precision and accurate end point detection
Solution Approach 2:
The system performs preliminary characterization of the workpiece material and processing conditions before actual processing. Based on this preliminary information, optimal detection parameters and end point criteria are pre-established, allowing for more accurate real-time end point detection during the actual material deposition or removal process
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
This approach enhances the accuracy of end point detection, reducing statistical noise and ensuring precise control over material deposition or removal, thereby improving the quality and reliability of the processing results.
Implementation Method 1
The electrons emitted by the object as a consequence of the striking of the electron beam and/or electrons backscattered at the object are detected
Implementation Method 2
electrons backscattered at the object are detected in order to compose an electron image of the scanned region
Implementation Method 3
material is deposited or removed selectively and with high precision by feeding to a site to be processed on the object a reaction gas that is excited by the electron beam striking the site to be processed on the object and becomes chemically reactive
Data Source
Figure 1
Figure 2a~2d
Figure 3
AI summary
The present invention relates to a method for processing an object with miniaturized structures, having the steps of: a) feeding the reaction gas onto a surface of the object; b) processing the object by directing an energetic beam onto a processing site on the surface of the object, in order to deposit material on the object or to remove material from the object, c) scanning the surface of the object with the energetic beam and detecting interaction products of the energetic beam with the object, and d) deciding whether the processing of the object must be continued or can be terminated with the aid of information which is obtained from the detected interaction products of the energetic beam with the object, e) in which the processing of the object in step b) is performed with a first set of beam parameters of the beam, and the scanning of the surface in step c) is performed with a second set of beam parameters of the energetic beam, and the second set of beam parameters deviates from the first set of the energetic beam parameters.