A New In-line Laser-based Acoustic Technique for Pillar Bump Metrology
Autor: | Xueping Ru, Andrew Bakir, Michael Kotelyanskii, Jonathan Cohen, Manjusha Mehendale, Michelle T. Schulberg, Priya Mukundhan, Robin Mair, David M. Stobbe, Todd W. Murray, T. Kryman |
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Rok vydání: | 2015 |
Předmět: |
Thermal copper pillar bump
Interconnection Materials science Computer Networks and Communications business.industry Pillar 02 engineering and technology 021001 nanoscience & nanotechnology Laser Engineering physics Line (electrical engineering) Electronic Optical and Magnetic Materials Metrology law.invention Optics law Automotive Engineering Electrical and Electronic Engineering 0210 nano-technology business |
Zdroj: | International Symposium on Microelectronics. 2015:000486-000492 |
ISSN: | 2380-4505 |
Popis: | The drive to reduce the interconnect pitch and increase the number of connections for packaging in mobile devices has led to the development of copper pillar bumps. The key drivers for the adoption of copper pillars are improved performance, reduced form factor and lower cost. In this paper, we present a laser-based acoustic technique for the characterization of multi-layer pillars. This non-contact technique has a high sensitivity for materials characterization with micron-scale spatial resolution. Absorption of laser light causes excitation of elastic waves that propagate through the pillar and are reflected by the pillar walls, exciting vibrational modes in the structure. We have demonstrated that our approach is sensitive to the thicknesses of individual layers in bi-layer and tri-layer copper pillar stacks. Focused ion beam scanning electron microscopy (FIB SEM) has been used to optimize the model and to validate the accuracy of the technique. |
Databáze: | OpenAIRE |
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