Ultra-Thick and High-Aspect-Ratio Nickel Microgyroscope Using EFAB TM Multi-Layer Additive Electroforming

Abstract

This paper presents a 240 µ m-thick nickel microgyroscope with a lateral aspect ratio greater than 100, fabricated using the EFAB TM commercial multi-layer additive electroforming process. The fabricated gyroscope demonstrates a measured mechanical sensitivity of 65 µ V/(deg/sec) and a noise-equivalent rate of 0.086deg/sec at atmospheric pressure in a measurement bandwidth of 1Hz, using a capacitive interface circuit constructed from off-the-shelf components. The gyroscope’s measurement bandwidth approaches to 100Hz. The variation of the drive-mode resonance frequency is measured to be better than 0.1% within 40 hours period, demonstrating the reliability of the electroformed nickel of the EFAB TM process. The gyroscope is sensitive to rotations about an in-plane axis, and therefore, allows implementation of a two-axis rate sensor on the same substrate.