Internal Stress Actuated Micro-Nanomachines for Material Testing
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Solution Overview
Problem
Current methods for measuring mechanical and electromechanical properties of micro- and nano-scale materials are challenging due to specimen fragility, loading uniformity, inadequate load resolution, and sensitivity to precise dimensional measurements, particularly for thin films and multi-layers, which limits their precision, reliability, and cost-effectiveness.
Innovation Solution
The development of internal stress actuated micro- and nano-tensometers that utilize the difference in thermal expansion coefficients between a thin film actuator and a substrate to induce deformation in the material sample, allowing for precise measurement of mechanical properties by releasing internal stress through chemical or physical means, such as etching, and applying additional stresses like electrostatic, magnetic, or thermal means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external force application methods (e.g., nano-indenter) are used to measure mechanical properties, then measurement capability is achieved, but device complexity and handling difficulty increase
Solution Approach 1:
The thin film structure serves its own actuator function through internally generated stress, eliminating the need for external actuators or complex loading mechanisms. The structure deforms itself under internal stress, and this self-deformation is measured to determine mechanical properties, thereby simplifying the overall testing system while maintaining measurement precision.
Solution Approach 2:
The patent replaces traditional mechanical loading systems (nano-indenter, external actuators) with an internal stress-based system. Instead of applying external mechanical force, the measurement is based on detecting the structure's response to internally generated stress, substituting a complex mechanical system with a simpler stress detection approach.
2Ease of operation
If calibrated systems are used to estimate load, then measurement is possible, but measurement precision deteriorates due to calibration requirements
Solution Approach 1:
The thin film structure generates its own internal stress without requiring external calibration systems. The internal stress is inherent to the structure's fabrication process, eliminating the need for separate calibration procedures and associated precision losses, while maintaining ease of operation.
3Productivity
If conventional mechanical testing is used on micro- and nano-scale specimens, then testing can be performed, but reliability decreases due to specimen damage and handling difficulties
Solution Approach 1:
The specimen performs its own testing by deforming under internal stress without requiring external handling or gripping. This eliminates handling-induced damage and improves reliability while maintaining testing capability. The structure is released from its substrate and allowed to self-deform, ensuring specimen integrity throughout the process.
4Force
If external actuators are used to apply force, then loading can be applied, but device complexity increases
Solution Approach 1:
The thin film structure generates its own actuating force through internal stress developed during fabrication. This self-generated force eliminates the need for external actuators, significantly reducing device complexity while maintaining adequate loading capability for micro- and nano-scale specimens.
Solution Approach 2:
The internal stress in the thin film is controlled by changing fabrication parameters such as deposition temperature, film thickness, and material composition. By adjusting these parameters, the magnitude of internal stress can be tuned to provide appropriate loading levels without requiring complex actuator systems.
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 enables precise, reliable, and cost-effective measurement of mechanical properties by using internal stress to deform the material sample, providing accurate internal stress-strain curves and overcoming the limitations of existing methods, particularly for materials with dimensions smaller than 10 µm.
Implementation Method 1
utilize the difference in thermal expansion coefficients between a thin film actuator and a substrate to induce deformation
Implementation Method 2
releasing internal stress through chemical or physical means, such as etching
Data Source
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AI summary
This invention provides an internal stress actuated micro- or nano- machine for measuring mechanical and/or electrical properties, e.g. traction measurement, compression measurement or shear measurement, on micro- scale and nano-scale films or multi-layers of materials such as metallic materials, carbon-based materials and silicon-base materials. The device of the invention has applications in materials production industry, as well as in micro-electronics and for surface treatments and functionalization.