Length Measurements of Reflecting Films using an Optical Interferometer ASTM E2244

Scope:

ASTM E2244 test method determines the in-plane length and deflection of reflecting films in unproven fabrication processes. It helps receive the topographical 3-D data sets through the use of an interferometric microscope. The measurements obtained can be used in parameter calculations, such as Young’s modulus and strain. In-plane deflection values are essential for various test structures. 

Procedure:

Transitional edges are selected and aligned for obtaining a 3-D data set. Four 2-D data traces are obtained from a 3-D data set for the examination of transitional advantages. Temperature and humidity are recorded, and transitional edges are arranged as per the intensity of brightness. The endpoints and uncertainties are determined, and the misalignment is rectified. The direction of the transitional edges is recorded, and data traces are calculated for every possibility. The final length is the average of the four calibrated values. 

Specimen size

Specimen size should be as required, within 10 µm.

Data:

The available symbols used in the calculation are as follows:
α = the misalignment angle.
L = the in-plane length measurement that accounts for misalignment.
L_align = the corrected in-plane length.
While measuring in-plane deflection, L can be replaced by D, which stands for ‘deflection.’