Limitations of measuring methods for the depth of the groove

Project Description

Co-ordinate NMI

If the nature of the measuring method i.e. capabilities of measuring equipment give a possibility to measure roughness parameters on the repetitive rectangular grooves, those additional measurements shall be conducted.

Final Report 2011-09-11

Measurements of groove depth were preformed on roughness referent standards, property of Laboratory for precise measurement of length (LFSB). LFSB is a constitutive part of HMI. Measured standards have two measurement surfaces, one with repetitive rectangular SiO2 grooves and second with wide rectangular SiO2 grooves. Measurement surfaces are partly Au coated for optical instruments. Measurements were carried out on seven roughness standards with different nominal values of groove depths, ranging from 100 nm up to 4000 nm. Standards were measured using following measurement equipment:

• Stylus instrument Perthometer C5D - HMI
• Interferometric microscope Epival-Interphako - HMI
• Elipsometer AutoEL IV - HMI
• Stylus profilometer Talystep 1 - INRIM
• AFM Thermomicroscope Autoprobe CP - NIS
• Interferometer Zygo NewView 200 (wls, fs) - NIS 

Obtained measurement results revealed:

1. A good agreement within the declared levels of measurement uncertainties, with the exception of the results achieved on the AFM. Further research was set in order to identify causes for systematic error establish on the AFM.
2. Measurement areas, with respect to the applied measurement methods, are produced by different technologies. Therefore, there is a question of the influence of various measurement surfaces on the measurement results obtained with different methods.
3. The problem with size of the standards has appeared during the AFM measurements. Namely, the samples are 50 mm in diameter and as such cannot be measured by a majority of SPM's due to the size limitations of the set-up of those instruments. 

With regard to measurement results achieved within this project, and based on information’s about standards available today in the area and dimensional micro and nanometrology, a new roughness standard is designed and partially produced.