Electrochemical Deposition of Platinum Interconnects on Flexible Biocompatible Substrates
- PDF / 2,661,508 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 39 Downloads / 206 Views
Electrochemical Deposition of Platinum Interconnects on Flexible Biocompatible Substrates A. Radisic1, B. M. Morcos1, 2, 3, M. Op de Beeck1, J. M. O’Callaghan1, and C. Van Hoof1 1 imec, Kapeldreef 75, Leuven, Belgium 2 KACST-Intel Consortium CENA, Riyadh, Saudi Arabia 3 Chemistry Department, Faculty of Science, Alexandria University, Egypt ABSTRACT We explored the use of galvanostatic electrochemical deposition of Pt for cost-effective fabrication of interconnects in flexible implantable bio-medical devices. Initial studies were done on coupons diced from 200 mm Si wafers coated with PVD TiN. Based on the physical and chemical properties of the electrodeposited Pt films, optimal conditions were chosen for through-mask plating of centimeters long Pt lines on flexible, medical grade, releasable polyimide layers. Possibility for further up-scaling was considered with special emphasis on high throughput manufacturing of Pt interconnects with good adhesion to TiN/flexible substrates, low impurity content and resistivity, and acceptable roughness and uniformity. INTRODUCTION Implantable devices for bio-medical applications are typically placed in a rigid biocompatible packaging (e.g. Ti box) which provides hermetic enclosure for the electronic components. While such an enclosure is well-studied and deemed generally safe, it is often large compared to the electronics inside, requiring large insertion opening during implantation. Pronounced foreign-body-reaction (FBR), higher infection risk, and irritation due to the strong mismatch in properties of the soft body tissue and the rigid encapsulating materials could also accompany the device implantation [1-3]. To alleviate or reduce these risks one could consider implant packaging made of soft, biomimetic materials, and explore the miniaturization techniques from microelectronics industry to make the device as compact as possible. In one of the reported approaches [2, 3], individual sub-devices are manufactured using standard waferscale microelectronics processing techniques, and placed on a thin flexible carrier, made from medical grade polyimide. The sub-devices are then electrically connected through Pt interconnects, and finally encapsulated in another layer of polyimide. Pt is the material of choice for interconnects due to its biocompatibility, high corrosion resistance and conductivity. Out of two commonly used Pt deposition techniques, physical vapor deposition (PVD) (or sputtering) and electrodeposition, electrodeposition was considered more cost-effective when only part (< 30%) of the wafer was to be metallized [2, 3]. Cost of ownership calculations included the costs of materials, tools, labor, etc for one Pt metallization step on a 200 mm wafer. In these calculations it was assumed that wafer-scale Pt plating is not a challenge and produces quality Pt interconnects on par with PVD techniques. However, examples from the literature [4] show that morphology, microstructure, and electrochemical properties of platinum thin films deposited from aqueous electrolytes stro
Data Loading...
