Discriminative non-destructive imaging of flip chips based on photoacoustic remote sensing microscopy with layered elasto-optic models
Discriminative internal imaging for different chip layers can pinpoint the location of critical defect in the flip chips, yet existing methods face challenges in in-line imaging to identify defects or structures from the sub-surface within the silicon substrate and their underlying coating. To addre...
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Veröffentlicht in: | Optics express 2024-06, Vol.32 (13), p.22700 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Discriminative internal imaging for different chip layers can pinpoint the location of critical defect in the flip chips, yet existing methods face challenges in in-line imaging to identify defects or structures from the sub-surface within the silicon substrate and their underlying coating. To address these challenges, we develop and verify layered elasto-optic models for photoacoustic remote sensing microscopy (PARS) that distinguish structures from multi-layers within a single device for in-line flip-chip wafer inspection. A finite-difference time-domain algorithm based on transparent source (TS-FDTD) accurately predicts different initial slopes of PARS signals within the silicon-metal and the silicon-air models. The initial slopes of PARS signals are experimentally validated and utilized for discriminative non-destructive imaging of the interdigital electrode chips and silicon cracks within the same region of interest. PARS with layered elasto-optic models and non-contact fast scanning has the potential for in-line detection of defects from various layered structures with different refractive indices, offering an approach for discriminative non-destructive testing (NDT) of flip-chip and layered structures. |
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ISSN: | 1094-4087 1094-4087 |
DOI: | 10.1364/OE.524193 |