A novel capillary-effect-based solder pump structure and its potential application for through-wafer interconnection

• Published in: Journal of micromechanics and microengineering 2009-07, Vol.19 (7), p.074005-074005 (7), Article 074005
• Main Authors: Gu, Jiebin, Pike, W T, Karl, W J
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/19/7/074005

Through-wafer electrical interconnection is a critical technology for advanced packaging. In this paper, a novel capillary-effect-based solder pump has been proposed and analyzed, which could produce interconnects through and between silicon dies. The principle of this pump is to use the surface tension of a molten solder, introduced in the form of balls, to drive sufficient material into a deep reactive-ion etched hole to form a through-wafer conductive path. The solder pump structure uses unwettable through-wafer holes of different diameters together with wettable metallization on two dies to provide the pressure differential and flow path. Using multiple feed holes and a single via hole complete through-wafer interconnects are demonstrated.