Showing papers by "Mohammed N. Islam published in 2010"
TL;DR: It is shown that the maximum measurable angular tilt from the sample surface normal for a given source power depends on the surface roughness of the sample.
Abstract: A line scan interferometer, which comprises a visible supercontinuum source coupled to Fourier domain Michelson interferometer, is used to obtain 3D images of ~300 μm high solder balls on a semiconductor die with 125 nm axial and 15 μm lateral resolution. The ability to measure curved surfaces enables the determination of solder ball shape defects in addition to ball height. We show that the maximum measurable angular tilt from the sample surface normal for a given source power depends on the surface roughness of the sample. As an example, we demonstrate height measurement over +/-20 degrees from the normal on the solder balls and over +/-60 degrees on a rough steel ball bearing sample.
14 citations
16 May 2010
TL;DR: This paper measured the RMS roughness of crankshaft journals from 0.05-0.13microns at a 45degree angle of incidence and 70cm standoff distance.
Abstract: We measure the RMS roughness of crankshaft journals from 0.05–0.13microns at a 45degree angle of incidence and 70cm standoff distance. The system is used to detect and sort journals not polished to specifications.
6 citations
TL;DR: In this article, an optical probe for detection of porosity inside spool bores of a transmission valve body with diameters down to 5 mm is presented, which consists of a graded-index relay rod that focuses a laser beam spot onto the inner surface of the bore.
Abstract: We demonstrate an optical probe for detection of porosity inside spool bores of a transmission valve body with diameters down to 5 mm. The probe consists of a graded-index relay rod that focuses a laser beam spot onto the inner surface of the bore. Detectors, placed in the specular and grazing directions with respect to the incident beam, measure the change in scattered intensity when a surface defect is encountered. Based on the scattering signatures in the two directions, the system can also validate the depth of the defect and distinguish porosity from bump-type defects coming out of the metal surface. The system can detect porosity down to a 50-µm lateral dimension and ~40 µm in depth with >3-dB contrast over the background intensity fluctuations. Porosity detection systems currently use manual inspection techniques on the plant floor, and the demonstrated probe provides a noncontact technique that can help automotive manufacturers meet high-quality standards during production.
5 citations
16 May 2010
TL;DR: In this article, a broadband line scan interferometer was used to identify shape defects on ∼300µm high solder balls by measuring the 3D profile over +/−20 degrees down the ball surface.
Abstract: We identify shape defects on ∼300µm high solder balls by measuring the 3D profile over +/−20 degrees down the ball surface. A broadband line scan interferometer enables measurement of ball height with 125nm axial resolution.
2 citations
16 May 2010
TL;DR: In this article, an optical probe with ∼50 µm lateral resolution was used to inspect the inner surfaces of valve body spool bores down to 5 mm diameter for porosity defects.
Abstract: We inspect inner surfaces of valve body spool bores down to 5 mm diameter for porosity defects, using an optical probe with ∼50 µm lateral resolution. The probe can also distinguish porosity from bump-type defects.