First demonstration of a temporal coherence analysis through a parametric interferometer

2008 ◽  
Vol 281 (10) ◽  
pp. 2722-2726 ◽  
Author(s):  
L. Del Rio ◽  
M. Ribiere ◽  
L. Delage ◽  
F. Reynaud
Keyword(s):  
Temporal Coherence ◽  
Coherence Analysis

Defect Detection of Flip Chip Solder Bumps Through Local Temporal Coherence Analysis of Laser Ultrasound Signals

2007 ◽  
Author(s):  
Jin Yang ◽  
Charles Ume
Keyword(s):  
Defect Detection ◽  
Flip Chip ◽  
Solder Bump ◽  
Temporal Coherence ◽  
Coherence Analysis ◽  
Laser Ultrasound ◽  
Surface Mount ◽  
Flip Chips ◽  
Solder Bumps ◽  
Ultrasound Signals

Microelectronics packaging technology has evolved from through-hole and bulk configuration to surface-mount and small-profile ones. In surface mount packaging, such as flip chips, chip scale packages (CSP), and ball grid arrays (BGA), chips/packages are attached to the substrates or printed wiring boards (PWB) using solder bump interconnections. Solder bumps, which are hidden between the device and the substrate/board, are no longer visible for inspection. A novel solder bump inspection system has been developed using laser ultrasound and interferometric techniques. This system has been successfully applied to detect solder bump defects including missing, misaligned, open, and cracked solder bumps in flip chips, and chip scale packages. This system uses a pulsed Nd:YAG laser to induce ultrasound in the thermoelastic regime and the transient out-of-plane displacement response on the device surface is measured using the interferometric technique. In this paper, local temporal coherence (LTC) analysis of laser ultrasound signals is presented and compared to previous signal processing methods, including Error Ratio and Correlation Coefficient. The results show that local temporal coherence analysis increases measurement sensitivity for inspecting solder bumps in packaged electronic devices. Laser ultrasound inspection results are also compared with X-ray and C-mode Scanning Acoustic Microscopy (CSAM) results. In particular, this paper discusses defect detection for a 6.35mm×6.35mm×0.6mm PB18 flip chip and a flip chip (SiMAF) with 24 lead-free solder bumps. These two flip chip specimens are both non-underfilled.

scholarly journals Effect of spectral sampling on the temporal coherence analysis of a broadband source in a SFG interferometer

2015 ◽  
Vol 23 (20) ◽  
pp. 25450 ◽  
Author(s):  
Pascaline Darré ◽  
Ludovic Szemendera ◽  
Ludovic Grossard ◽  
Laurent Delage ◽  
François Reynaud
Keyword(s):  
Temporal Coherence ◽  
Coherence Analysis ◽  
Spectral Sampling

Principle and practice of high-resolution imaging with a field-emission TEM

1992 ◽  
Vol 50 (1) ◽  
pp. 138-139
Author(s):  
Max T. Otten ◽  
Wim M.J. Coene
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Incidence Angle ◽  
Temporal Coherence ◽  
Energy Spread ◽  
High Resolution Imaging ◽  
Major Improvement ◽  
High Resolution Images ◽  
Resolution Imaging

High-resolution imaging with a LaB6 instrument is limited by the spatial and temporal coherence, with little contrast remaining beyond the point resolution. A Field Emission Gun (FEG) reduces the incidence angle by a factor 5 to 10 and the energy spread by 2 to 3. Since the incidence angle is the dominant limitation for LaB6 the FEG provides a major improvement in contrast transfer, reducing the information limit to roughly one half of the point resolution. The strong improvement, predicted from high-resolution theory, can be seen readily in diffractograms (Fig. 1) and high-resolution images (Fig. 2). Even if the information in the image is limited deliberately to the point resolution by using an objective aperture, the improved contrast transfer close to the point resolution (Fig. 1) is already worthwhile.

ANALISIS KOHESI DAN KOHORENSI DALAM WACANA BERITA KEMISKINAN DAN RAMADHAN DALAM KORAN REPUBLIKA

2019 ◽  
Vol 1 (01) ◽  
pp. 1-6
Author(s):  
Resdianto Permata Raharjo ◽  
Ahmad Sudali
Keyword(s):  
Qualitative Research ◽  
Data Collection ◽  
The Other ◽  
Coherence Analysis ◽  
Lexical Cohesion ◽  
News Discourse ◽  
The Relationship

This journal explains the results of cohesion and coherence analysis in the current new news discourse in Indonesia published by Republika, Thursday 16 May 2019. The research uses descriptive methods by describing and explaining the results of the analysis found in the study. This research is a type of qualitative research because the results tend to be released and descriptive. the technique used in this study is to take data, data collection is done in two ways, namely listening and taking notes. This study found the results of the use of cohesion and and the use of coherence. Cohesion is the integration between the parts that are characterized by the use of language elements. Cohesion is divided into two parts, lexical cohesion and grammatical cohesion. Grammatical cohesion includes conjunction, reference, release, substitution. Lexical cohesion includes antonyms, synonyms, repetitions, metonymy, and hypomini. Whereas, cohorence is the relationship between elements one with the other elements so that it has an integrated meaning.  

Coherence Analysis of the Space Launch System using Unsteady Pressure Sensitive Paint

2021 ◽  
Author(s):  
Francesco Soranna ◽  
Martin K. Sekula ◽  
Patrick S. Heaney ◽  
James M. Ramey ◽  
David J. Piatak
Keyword(s):  
Coherence Analysis ◽  
Pressure Sensitive Paint ◽  
Unsteady Pressure ◽  
Pressure Sensitive ◽  
Space Launch
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