Towards Quantitative AFM Nanomechanical Metrology for Advanced Semiconductor Patterning

The continuous scaling of semiconductor technology is driving increasingly small feature dimensions and pitches, enabled by advanced patterning technologies such as high-NA EUV lithography. As critical dimensions (CDs) continue to shrink and material stacks become increasingly complex, the mechanical properties of photoresists, underlayers, and hard masks may increasingly influence pattern stability, roughness, defect formation, and pattern-transfer performance. This creates a growing need for metrology techniques capable of measuring these properties at the relevant nanometre scale.

AFM-based nanomechanical characterization is particularly attractive because atomic force microscopy (AFM) can probe the local mechanical response while simultaneously mapping surface topography at nanometre-scale sampling intervals. Depending on the measurement mode, the probed response may be contact stiffness, elastic modulus, adhesion, deformation, etc. However, turning this nanomechanical contrast into reliable quantitative material properties remains challenging because the measured response can depend on tip geometry, probe calibration, tip–sample contact mechanics, viscoelastic effects, applied load and other measurement conditions. For ultrathin films and nanoscale patterns, substrate and edge effects can further influence the measured response.

Therefore, the goal of this Master’s thesis (internship) is to determine when AFM-based nanomechanical measurements can provide repeatable and quantitatively interpretable information, within a defined range of materials, film thicknesses, and sample geometries, for advanced semiconductor-patterning materials.

The student will:

• Evaluate different AFM nanomechanical approaches in terms of sensitivity and measurement repeatability for use on semiconductor-patterning materials.
• Investigate the influence of selected experimental parameters on the measured mechanical response, with particular emphasis on film-thickness and substrate effects.
• Assess the main measurement artefacts associated with substrate contribution, nanoscale topography, and pattern edges, and identify conditions under which the measured nanomechanical response can be reliably interpreted.
• Develop an uncertainty-aware measurement and data-analysis workflow for nanomechanical characterization of thin films and demonstrate its applicability to a representative nanoscale patterned sample.
• If time and suitable matched samples permit, explore whether a selected nanomechanical observable correlates with a relevant patterning metric, such as roughness or line deformation.

The project will provide the student with hands-on experience in advanced AFM techniques, nanoscale contact mechanics, experimental design, quantitative data analysis, and semiconductor-patterning metrology, while addressing a measurement challenge directly relevant to next-generation lithography.