Focused Ion Beam Apparatus Stage Shift Correction
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Solution Overview
Problem
Focused ion beam apparatuses face challenges in maintaining working location accuracy when the sample stage moves beyond the display range, as the positioning accuracy of the physical sample stage is lower than the ion beam emission, leading to errors in location detection and correction.
Innovation Solution
A focused ion beam apparatus with a control unit that detects and corrects the location of reference marks on the sample image after stage movement, allowing for precise adjustment of the ion beam emission location, even when working beyond the display range, by using a detector to generate and display sample images with location detection marks and controlling the sample stage movement based on pre-set working regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the working magnification is increased to improve working accuracy, then the working accuracy increases, but the field of view becomes too small to display all working regions
Solution Approach 1:
The patent divides the working process into multiple segments by using multiple location detection marks distributed across different regions of the sample. When the sample stage moves, the system can detect and switch between different marks to maintain continuous location correction throughout the entire working region, effectively segmenting the large-area working space into multiple correctable zones.
Solution Approach 2:
The patent introduces location detection marks as intermediary reference objects between the ion beam system and the sample. These marks serve as mediators for detecting stage movement and correcting working location shifts, enabling accurate position feedback even when the sample stage moves beyond the initial field of view.
2Area of stationary object
If the sample stage is moved to display all working regions, then the entire working region can be displayed, but location shift occurs due to mechanical positioning error
Solution Approach 1:
The patent implements a feedback mechanism by continuously detecting the positions of location detection marks after sample stage movement. The system compares the detected mark positions with pre-registered positions to calculate location shifts, then uses this feedback information to correct the working location, forming a closed-loop control system that compensates for mechanical positioning errors.
Solution Approach 2:
The patent performs preliminary registration of location detection mark positions before sample working. By pre-storing the correct positions of multiple reference marks across the entire working region, the system can quickly retrieve and use this reference information for location correction after stage movement, avoiding the need for time-consuming re-calibration.
3Measurement precision
If the ion beam is emitted multiple times to the location detection mark to detect its location, then the mark location can be detected, but the mark may be damaged by ion sputtering
Solution Approach 1:
The patent creates multiple copies of location detection marks distributed across different regions of the sample. Instead of repeatedly irradiating a single mark, the system can switch between multiple mark copies for detection purposes. This distributes the ion beam damage across multiple marks while preserving at least some recognizable marks for continued use as reference points.
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 solution enables high-accuracy working of the entire working region by correcting location shifts, ensuring precise ion beam placement and maintaining high working accuracy even when moving the sample stage beyond the display range.
Implementation Method 1
a focused ion beam emission mechanism configured to emit a focused ion beam to the sample
Implementation Method 2
a detector configured to detect secondary charged particles generated with the emission of the focused ion beam to the sample
Data Source
AI summary
A focused ion beam apparatus includes an image generation unit that generates a sample image including location detection marks formed on a sample based on secondary charged particles generated from the sample by emission of a focused ion beam to the sample, and a display that which displays a sample image. A control unit which, in a case of performing working by emitting the focused ion beam to a working region of the sample that is beyond a display range, moves a sample stage, detects locations of the location detection marks included in the sample image after the movement of the sample stage as reference marks from the location detection marks included in the sample image before moving the sample stage, and controls an emission location of the focused ion beam based on the reference marks detected in the sample image after movement of the sample stage to correct a working location shift due to movement of the sample stage.