Micromolding of Ni-P with Reduced Ferromagnetic Properties for 3D MEMS. Issue 5 (1st January 2017)

• Record Type: Journal Article
• Authors: Risquez, S.; Woytasik, M.; Cai, H.; Philippe, H.; Bayle, F.; Lefeuvre, E.; Moulin, J.
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 5(2017)
• Page Start: B3096
• Page End: B3100
• Publication Date: 2017-01-01
• Subjects: 3D -- additive process -- electrodeposition -- electrostatic -- energy harvesting -- MEMS -- Ni-P -- non-magnetic; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0151705jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : This paper presents the development of nickel phosphorus (Ni-P) micromolding for the manufacturing of a 3D electrostatic energy harvesting microsystem. Ni-P alloy exhibits weak ferromagnetic properties beyond 10–12 wt% phosphorus content. Deposits were prepared at different current densities (−10 to −150 mA/cm²) and concentration of phosphorous acid in the electrolyte (0–20 g/l). It was found that the deposition rate decreases when phosphorus content increases in the deposit. The final process leaded the choice of a H3 PO3 concentration of 5 g/l to reach a 0.1 μm/min deposition rate for phosphorus content higher than 13 wt%. Mechanical, electrical and magnetic properties of the Ni-P films were investigated on 1 mm² and 1 cm² square deposit and confirmed the suitability of that material for the target MEMS. Comb patterns of micromolded Ni-P have been realized on a 2-inch wafer, leading to a 10 μm thick deposit containing 13.5 wt% in P, which is, at our knowledge, the first high phosphorus Ni-P micromolding involving electrodeposition growth for 3D MEMS applications.