Title :
Residual stress mapping with a scanning phase-measuring acoustic microscope
Author :
Meeks, S.W. ; Peter, D. ; Horne, D. ; Young, K. ; Novotny, V.
Author_Institution :
IBM Almaden Res. Center, San Jose, CA, USA
Abstract :
A high-resolution scanning phase-measuring acoustic microscope (SPAM) has been developed, and using the acoustoelastic effect, has been used to image the near-surface residual stress field around features etched in sputtered alumina. This microscope operates at 670 MHz and has a resolution of 5-10 μm, depending upon the amount of defocus. Relative-velocity changes of sample surface waves as small as 50 parts per million are resolved. Images of the stress field at the tip of a 400-μm-wide slot etched in alumina are presented and compared with a finite element simulation. The SPAM uses an unconventional acoustic lens with an anisotropic illumination pattern which can measure anisotropic effects and map residual stress fields with several-micrometer resolution and a stress sensitivity of 1/3 MPa in an alumina film
Keywords :
acoustic microscopy; alumina; etching; internal stresses; sputtered coatings; stress measurement; 400 micron; 670 MHz; acoustic lens; acoustoelastic effect; anisotropic effects; anisotropic illumination pattern; defocus; finite element simulation; high-resolution scanning phase-measuring acoustic microscope; near-surface residual stress field; residual stress mapping; sample surface waves; slot; sputtered Al2O3; Acoustic measurements; Anisotropic magnetoresistance; Finite element methods; Lenses; Lighting; Microscopy; Residual stresses; Sputter etching; Surface acoustic waves; Unsolicited electronic mail;
Conference_Titel :
Ultrasonics Symposium, 1989. Proceedings., IEEE 1989
Conference_Location :
Montreal, Que.
DOI :
10.1109/ULTSYM.1989.67099
