Silicon microstructures and microactuators for compact computer disk drives

Abstract

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.