Orthogonal FIB-STEM Integrated Chamber for High-Throughput Thin Film Machining
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Solution Overview
Problem
Conventional FIB machining and STEM observation are typically performed using separate apparatuses, leading to inefficiencies in throughput and sample rotation requirements, with challenges in achieving high image resolution and accurate film thickness management, especially in low-energy STEM observations.
Innovation Solution
An integrated charged particle beam apparatus where the FIB and STEM systems are arranged to intersect almost orthogonally, allowing for simultaneous machining and observation without sample rotation, with the objective lenses positioned close to the sample to enhance resolution, and a compensation magnetic field is used to focus the ion beam, enabling high-accuracy film thickness regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FIB machining and STEM observation are performed using separate apparatuses, then each apparatus can be optimized for its specific function, but the throughput is reduced and sample rotation is required
Solution Approach 1:
The patent combines the FIB machining system and STEM observation system into a single integrated apparatus. The ion beam irradiation system for FIB machining and the electron beam irradiation system for STEM observation are merged in one device, allowing both functions to be performed on the same sample without physical transfer or rotation, thereby improving throughput while managing integration complexity through shared sample chamber and coordinated beam control
2Ease of operation
If the ion beam axis intersects the electron beam axis at an acute angle, then the apparatus layout is compact, but the sample must be rotated between FIB machining and STEM observation
Solution Approach 1:
The patent employs an asymmetric orthogonal arrangement where the ion beam axis and electron beam axis intersect at approximately 90 degrees rather than at acute angles. This asymmetric configuration allows the sample to remain in a fixed orientation during both FIB machining and STEM observation, eliminating the need for sample rotation while managing the spatial requirements through optimized positioning of the sample holder at the intersection point
3Measurement precision
If the objective lenses are positioned far from the sample, then the apparatus structure is simplified, but the image resolution is reduced
Solution Approach 1:
The patent positions the objective lenses in a configuration where they are located as close as possible to the sample in the vertical dimension, with the electron beam objective lens positioned above the sample and the ion beam objective lens positioned below or at an angle. This spatial arrangement in multiple dimensions allows high-resolution imaging and machining while managing the complexity through coordinated positioning mechanisms that maintain the required close proximity during both FIB and STEM operations
4Object-affected harmful factors
If FIB machining is performed at low energy, then the beam damage is reduced, but the film thickness management accuracy is compromised
Solution Approach 1:
The patent implements dynamic energy parameter changes during the FIB machining process. The system can adjust the ion beam energy level based on the machining stage: using lower energies for final precision work to minimize damage and higher energies for bulk material removal. Combined with real-time STEM observation and automated feedback control, this parameter adjustment strategy achieves both reduced beam damage and accurate film thickness management
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 setup enables high-throughput FIB machining and high-resolution STEM observation in a single sample chamber, simplifying sample thickness optimization and improving image resolution, while maintaining high machining accuracy and throughput.
Implementation Method 1
By applying an FIB to a sample, it is possible to perform micro-machining using the sputtering phenomenon.
Implementation Method 2
by introducing a deposition gas into the vicinity of the FIB irradiation of the sample and performing the FIB irradiation in the gas atmosphere, a deposition film is formed by the ion beam assisted deposition phenomenon
Implementation Method 3
the sample for observation by using the STEM fabricated by the FIB machining is placed at the intersection of the ion beam axis and the electron beam axis and can be additionally machined by the FIB and observed by the STEM
Data Source
AI summary
It is possible to carry out a highly accurate thin film machining by irradiation of an ion beam to a sample and a high-resolution STEM observation of the sample by irradiating an electron beam with a high throughput almost without moving the sample. The FIB irradiation system has an irradiation axis almost orthogonally intersecting an irradiation axis of the STEM observation electron beam irradiation system. The sample is arranged at the intersection point of the irradiation axes. The FIB machining plane of the sample is extracted from the thin film plane of the STEM observation sample. The transmitting/scattered beam detector are arranged at backward of the sample on the electron beam irradiation axis viewed from the electron beam irradiation direction.