There has been an increasing interest in recent years for lithium ion microbatteries for microelectromechanical systems (MEMs) integrated devices on silicon substrates. These thin film energy sources may be patterned and integrated on chip to match the specific requirements of the system. Minimising the footprint of such devices while maintaining the capacity and current drain capability is desirable to maximise the integration per substrate. One of the techniques that may be employed while utilising standard thin film battery materials is to structure the substrate prior to active materials deposition. This increases the quantity of available active material and the surface area for current drain while maintaining the optimised planar active layer thickness in the same footprint area. This paper describes lithographic techniques for patterning planar substrates to achieve microbattery materials compatible 3 D nickel substrates for sequential deposition of active battery materials. A single spin negative photoresist is used to achieve 90 µm height. After patterning, nickel is electroplated on the substrates from a low stress nickel sulfamate bath to a maximum of 90 µm. The sidewall angle achieved is in the range 6-9° yielding a thinner nickel feature at the surface level than at the base which is a key parameter to facilitate subsequent active battery materials deposition by vacuum deposition techniques. Aspect ratios of 1.5 to 1 have been achieved and the surface area may be doubled using this process by comparison with planar electrodes.

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