Silicon micromachined SCALED technology

Silicon micromachining technology will play an important role in the fabrication of high-bandwidth servo controlled microelectromechanical (mechatronic) components for super-compact disk drives. At the University of California, Los Angeles, and the California Institute of Technology, for the last three years, we have initiated a number of industry-supported joint research projects to develop the necessary technology building blocks for an integrated drive design of the future. These efforts include a silicon read/write head microgimbal with integrated electrical and mechanical interconnects, which targets the next-generation 30% form factor pico-sliders, and an electromagnetic piggyback microactuator in super-high-track-density applications, both of which utilize state-of-the-art silicon micromachining fabrication techniques

Silicon micromachined SCALED technology

Silicon micromachining technology will play an important role in the fabrication of high-bandwidth servo controlled microelectromechanical (mechatronic) components for super-compact disk drives. At the University of California, Los Angeles, and the California Institute of Technology, for the last three years, we have initiated a number of industry-supported joint research projects to develop the necessary technology building blocks for an integrated drive design of the future. These efforts include a silicon read/write head microgimbal with integrated electrical and mechanical interconnects, which targets the next-generation 30% form factor pico-sliders, and an electromagnetic piggyback microactuator in super-high-track-density applications, both of which utilize state-of-the-art silicon micromachining fabrication techniques

Silicon microstructures and microactuators for compact computer disk drives

Silicon micromachining techniques offer many exciting opportunities for fabricating both passive microstructures and active electromagnetic microactuators for significant form factor reduction and increase in recording density of future magnetic recording rigid disk drives. In this overview paper, the authors have presented some recent results and novel product concepts

Silicon microstructures and microactuators for compact computer disk drives

In 1956, IBM shipped the first magnetic rigid disk drive. It was 24 inches in diameter; fitted inside a box the size of an industrial size refrigerator; stored 5 megabytes, and sold for tens of thousands of dollars. In 1983, Seagate shipped the first magnetic disk drive for the PC market which was 5-1/4 inch in diameter; fitted in a box half the size of a shoebox, also stored 5 megabytes and sold for less than $1,500. In 1992, HP shipped what is still the world’s smallest commercially available rigid disk drive, which is 1.3 inch in diameter; fitted in a box the size of a matchbook, stored 20 megabytes, and sold for$150. In terms of both areal storage density and cost per megabyte, this progress has far exceeded the so-called 10-10 rules of the semiconductor industry, which is an order of magnitude improvement in 10 years. In fact, since 1991 magnetic recording disk drives have doubled in performance every eighteen months, and as a result, have maintained at least an order of magnitude cost advantage over solid-state memory and have long since surpassed optical recording in terms of storage density and capacity per drive. It is projected that in another five years, the industry will be capable of delivering credit-card size gigabyte disk drive cartridges at about 10 cents per megabyte. At UCLA and Caltech, we believe silicon micromachining technology will play an important role in the fabrication of high-bandwidth, servo-controlled miniaturized microelectromechanical components for such super-high-capacity, supercompact computer disk drives. For the past four years, we have been collaborating on a number of industry and government supported joint research projects to develop the necessary technology building blocks for design of a low-cost integrated drive of the future. These efforts include the design and fabrication of a silicon read/write head, microgimbaled with integrated electrical and mechanical interconnects, which targets the next-generation, 30 percent form factor pico-sliders. The efforts also include an electromagnetic piggyback planar microactuator for super high-track-density applications. Both efforts utilize state-of-the-art silicon micromachining fabrication techniques

INVESTIGATION INTO SUBMICRON TRACK POSITIONING AND FOLLOWING TECHNOLOGY FOR COMPUTER MAGNETIC DISKS

In the recent past some magnetic heads with submicron trackwidth have been developed in order to increase track density of computer magnetic disks, however a servo control system for a submicron trackwidth head has not been investigated. The main objectives of this work are to investigate and develop a new servo pattern recording model, a new position sensor, actuator, servo controller used for submicron track positioning and following on a computer hard disk with ultrahigh track density, to increase its capacity. In this position sensor study, new modes of reading and writing servo information for longitudinal and perpendicular magnetic recording have been developed. The read/write processes in the model have been studied including the recording trackwidth, the bit length, the length and shape of the transition, the relationship between the length of the MR head and the recording wavelength, and the SIN of readout. lt has also been investigated that the servo patterns are magnetized along the radial direction by a transverse writing head that is aligned at right angles with the normal data head and the servo signals are reproduced by a transverse MR head with its stripe and pole gap tangential to the circumferential direction. lt has been studied how the servo signal amplitude and linearity are affected by the length of the MR sensor and the distance between the shields of the head. Such things as the spacing and length of the servo-pattern elements have been optimised so as to achieve minimum jitter and maximum utilisation of the surface of the disk. The factors (i.e. the skew angle of the head) affecting the SIN of the position sensor have been analysed and demonstrated. As a further development, a buried servo method has been studied which uses a servo layer underneath the data layer, so that a continuous servo signal is obtained. A new piezo-electric bimorph actuator has been demonstrated. This can be used as a fine actuator in hard disk recording. The linearity and delay of its response are improved by designing a circuit and selecting a dimension of the bimorph element. A dual-stage actuator has been developed. A novel integrated fine actuator using a piezo-electric bimorph has also been designed. A new type of construction for a magnetic head and actuator has been studied. A servo controller for a dual-stage actuator has been developed. The wholly digital controller for positioning and following has been designed and its performances have been simulated by the MAL TAB computer program. A submicron servo track writer and a laser system measuring dynamic micro-movement of a magnetic head have been specially developed for this project. Finally, track positioning and following on 0.7 µm tracks with a 7% trackwidth rms runout has been demonstrated using the new servo method when the disk-was rotating at low speed. This is one of the best results in this field in the world