Thin Film Characterization

In the field of semiconductor and microtechnology, there are a variety of layer materials and multilayer systems with very different requirements for their thin film parameters. In addition to apparent parameters such as thickness, composition, mechanical stresses, and resistance, surface properties are crucial for many applications, as well. For example, bonding materials must have a certain surface energy (hydrophilic/hydrophobic) and display extremely low roughness values (<< 0.5 nm) in addition to exhibiting as few foreign atom deposits as possible.

Fraunhofer ENAS uses a variety of methods within in-line metrology for this range of thin film and surface characterization tasks:

  • Ellipsometer and reflectometer: characterization of single/multilayer thin films
  • AFM: determination of line and surface roughness of coatings and substrate materials
  • Four-point probe: characterization of thin film resistance and specific resistance
  • Stress measurement device: determination of mechanical stress in thin films and substrates

Additionally, certain processes, especially during development, require special thin film characterization methods that either do not or only partially allow further processing of the wafers:

  • Contact angle measuring device: determination of contact angle and surface engergy of coatings and substrate surfaces
  • EDX, FTIR, XPS, Raman: material analysis of coatings, substrates or contaminants
© Fraunhofer ENAS
2D AFM scan and evaluation of area roughness parameters after SiO2 CMP (AFM: Bruker Insight Cap)
© Fraunhofer ENAS
Thin film characterization of optically transparent layers (n/k) (top) as well as wafer map on the ellipsometer (bottom left) and reflectometer.
© Fraunhofer ENAS
Sheet resistance measurement
 

FRT Reflectometer

 

Atomic Force Microscopy

 

Ellipsometry

Additional Methods of Characterization

  • Thin film stress measurement system (Toho Technologies FLX 2320-S)
  • Coating resistance measurement (Polytec 280SI) 
  • Fourier transformation infrared spectroscopy (FTIR Spectrometer) 
  • X-ray photoelectron spectroscopy (XPS) 
  • Raman spectroscopy 
  • Contact angle measurement