SEM Charge Density Control for High Aspect Ratio Holes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional scanning electron microscopes face challenges in observing high aspect ratio contact holes due to non-uniform preliminary charge distribution, leading to potential gradients that cause image distortion and deviation in the field of view.
Innovation Solution
A scanning electron microscope design where the charge density in the inner area is reduced compared to the outer area within the scanned region, achieved by adjusting the scanning speed and beam irradiation patterns to create a uniform charge potential distribution without altering the electron microscope's lens conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If uniform beam scanning is used for preliminary charge, then the entire scanned area is charged, but a potential gradient is formed causing image distortion
Solution Approach 1:
The patent applies local quality by creating different charge densities in different regions of the scanned area. Specifically, the charge density in the inner area is made lower than in the outer area, which compensates for the potential gradient effect and prevents image distortion while maintaining adequate charge for electron detection.
2Manufacturing precision
If charge density in inner area is increased to suppress potential gradient, then image distortion is reduced, but charge uniformity is compromised
Solution Approach 1:
The patent changes the charge density parameter spatially across the scanned area. By making the charge density in the inner area lower than in the outer area, it creates a specific charge distribution pattern that suppresses potential gradients and prevents image distortion, achieving a balance between charge distribution and image quality.
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 effectively suppresses potential gradients within the scanned area, enabling precise observation and measurement of high aspect ratio contact holes without changing the electron microscope's optical conditions, thus preventing image distortion and ensuring accurate data acquisition.
Implementation Method 1
A scanning electron microscope (SEM) is an apparatus which detects secondary electrons (SE) and backscattered electrons (BSE) released from a sample by irradiating the sample with an electron beam
Implementation Method 2
an electrostatic lens or the like is not changed, beam scanning is performed so that a charge density in an inner area within a scanned area by the electron beam is lower than a charge density in an outer area within the scanned area
Data Source
AI summary
The present invention has an object to provide a scanning electron microscope which suppresses a potential gradient produced by preliminary charge without changing lens conditions of an electron microscope. As an aspect to achieve the above object, there is proposed a scanning electron microscope in which a scanning deflector is controlled so that a second beam is scanned to detect electrons released from a sample after scanning a first beam on the sample to charge the surface of the sample and the first beam is scanned so that charge density in a surrounding part within a scanned area by the first beam is increased relatively as compared with a center part within the scanned area by the first beam.