Integrated, variable-reluctance magnetic minimotor

Abstract

The use of lithography and electroplating to fabricate variable-reluctance, nearly planar, integrated minimotors with 6-mm-diameter rotors on silicon wafers is described. The motors consist of six electroplated Permalloy@ horseshoe-shaped cores that surround the rotor. Copper coils are formed around each core. The Permalloy and copper electroplating baths, electroplating seed layers, and through-mask plating techniques are similar to those used to fabricate inductive thin-film heads. High-aspect-ratio optical lithography or X-ray lithography was used to form the various resist layers. The rotors were fabricated separately, released from the substrate, and then slipped onto the shaft, which was plated as part of the stator fabrication process. The fabrication processes for stator and rotor are described in this paper, and initial minimotor operation data are presented.

Nucleation and growth of the electrodeposited iron layers in the presence of an external magnetic field

“…They have found a wide application in the magnetic storage [11,12] and in the microelectromechanical systems (MEMS) technology [13][14][15].…”

Stress Changes of Nanocrystalline CoNi Thin Films Electrodeposited from Chloride Baths

“…Numerous studies of electrodeposited iron group thin films ͑Fe, Co, and Ni͒ have been carried out because of potential applications in computer read/write heads, 1,2 microelectromechanical systems ͑MEMS͒, [3][4][5] and ultralarge scale integration ͑ULSI͒ devices. 6,7 Electrochemical processes ͑electrodeposition and electroless deposition͒ have many advantages over vacuum processes because of roomtemperature operation, various deposition parameters, easy scale up and maintenance, low production cost, relatively rapid deposition rate, the capability of handling complex geometries, and the ability to ''tailor'' deposit structure and properties.…”

Microelectromechanical Systems

“…An interesting application of Permalloy electroplating consists in the fabrication of magnetic micromotors utilizing soft magnetic materials for the stator and the rotor. A particularly illuminating implementation of this process is presented in [80], which compares two designs using either optical or X-ray lithography. Plated features included about 30-mm-thick conductors and 45-mm-thick Permalloy cores ( Fig.…”