PROBLEM:
The customer requested our help for the development of a Ultra High Vacuum (UHV) sample loader for a next-generation Scanning Electron Microscope.
CHALLENGES
Achieving and maintaining UHV conditions: achieving and maintaining UHV involves challenges related to material selection, outgassing rates, and seal integrity.
Mechanical design and precision: the sample loader had to be designed to precisely position samples without introducing contaminants. This required the use of flexure mechanisms and careful consideration of mechanical movements within a confined space.
Thermal considerations: the system had to be 150 degrees Celsius compatible to ensure UHV.
Cleanliness and contamination control: In SEM analysis, even minute particles can interfere with the imaging. The design of the sample loader may not introduce any contamination into the microscope.
Reliability and maintenance: the system had to be reliable and require minimal maintenance, as any downtime is costly.
- Material selection: materials used in UHV environments must have low outgassing rates and must not degrade or contaminate the vacuum. They also need to be compatible with the SEM environment, which requires non-magnetic materials.
PROBLEM:
The customer required a non-vibrating cryogenic cooler for an Electron Microscope. Achieving this goal presented several unique challenges that needed to be meticulously addressed to ensure the performance and reliability of the cooling system.
CHALLENGES
Thermal insulation: one of the paramount challenges was to minimize heat leakage into the system. At cryogenic temperatures, even minimal heat ingress can significantly impact the cooler’s efficiency. To combat this, we employed advanced insulation techniques, including vacuum insulation, radiation shields, and the use of materials renowned for their low thermal conductivity.
Material selection: material with a large heat capacity and high thermal conduction was needed to meet the requirements. Special consideration was given to the potential for deformation and stress, acknowledging that materials can exhibit markedly different behaviours at cryogenic temperatures versus ambient conditions. This careful selection ensures the cooler’s structural integrity and operational reliability.
Thermal modelling: to accurately predict the cooler’s performance, we utilized advanced thermal modelling techniques, including lumped-mass and Finite Element Method (FEM) models. These models are instrumental in understanding the thermal dynamics of the cooler, allowing us to optimize its design for the specific requirements.
PROBLEM:
The customer required a highly accurate positioning stage for a metrology system, tailored to handle heavy loads exceeding 50 kg. The challenge was to design and develop a system capable of operating in a vacuum environment of 1E-6 mbar, while maintaining sub-micrometer accuracy and stability.
CHALLENGES
Heavy load handling: developing a mechanism capable of accurately positioning loads exceeding 50 kg.
Vacuum environment: ensuring the system’s functionality and reliability in a high-vacuum environment of 1E-6 mbar.
Nanometer accuracy: achieving and maintaining positioning accuracy at the nanometer scale over a long positioning range.
Integration with metrology system: the stage had to seamlessly integrate with the metrology systems.
Temperature control: managing temperature fluctuations and thermal drift that affects the precision and stability of the positioning system.
PROBLEM:
The customer contacted us for the development and qualification of a test setup to verify the specifications of a newly designed vacuum seal. This seal is a critical component for future Extreme Ultraviolet (EUV) lithography machines.
CHALLENGES
Measuring creep and stiffness: assessing the vacuum seal’s material properties, particularly its creep behavior and stiffness, to ensure long-term reliability and performance.
Ensuring vacuum and leak tightness: testing the seal’s ability to maintain vacuum integrity and prevent leaks under different circumstances, critical for the functionality of the machine.
- High process forces: evaluating the seal’s resilience and durability under high mechanical forces encountered during operation.
PROBLEM:
The customer requested us to develop of a mask- and substrate aligner for the low-cost fabrication of periodic nano-structures.
CHALLENGES
6 DoF long-stroke/short-stroke motion with sub-micrometer resolution
Micro radian and sub-micron cross-coupling
Mask and substrate clamping mechanism
Substrate loading mechanism
Nanometer standstill performance
