Product Code: ICA11_M802

Development of Non-Planar Interconnects for Double-Sided Flexible Copper Substrates Using Laser Assisted Maskless Microdeposition Processes
Authors:
Steven Tong, University of Waterloo; Waterloo ON Canada
Elahe Jabari, University of Waterloo; Waterloo ON Canada
Hamidreza Alemohammad, University of Waterloo; Waterloo ON Canada
Ehsan Toyserkani, University of Waterloo; Waterloo ON Canada
Presented at ICALEO 2011

Non-planar interconnects has a permanent role in electronic packaging industry today. Interconnects allow manufacturers to save materials and space when connecting circuit components on flexible and non-planar substrates. Nowadays, double-sided flexible substrates (e.g., copper substrates separated by a layer of polyethylene terephthalate) have attracted the electronic industry to develop miniaturized flexible devices, such as sensors-on-chips, effectively and compactly. This study focuses on the creation of non-planar silver interconnects through micro-size holes between such conductive copper sides using laser-assisted maskless microdeposition (LAMM). In the LAMM process, which is a laser-based direct write technology, suspensions of silver nano-particles are used in a layer-by-layer deposition followed by post laser sintering.
The study includes the characterization of the LAMM process to achieve desired conductivity in the produced interconnects, which is the main indicator of performance for the electronic packages. Several parameters, including the deposition and laser processing parameters, are optimized to achieve interconnects free of pores, cracks and delimitation with reasonable bonding. For investigating the topography and microstructure of the interconnects, optical profilometry, scanning electron microscope(SEM), and X-ray diffraction(XRD) are used.