Ultra-high density magnetic heads

Most are amazed as the IC continues to increase density and improve speed. But, we have come to expect a doubling of density about every 18 months in tacit obedience to Moore's Law proposed so many years ago. Most do not realize, however, that another key player in electronics has not only kept pace, but clearly outstripped Moore's Law for the last 10 years. The magnetic storage industry, using principles of physics, electronics, optics, mechanics and electrical phenomenon, has continued to break density records, often several times a year. The hard disk drive (HDD) gets smaller, faster and cheaper every year. This protracted density extension has been accomplished recently by a breakthrough known as GMR (Giant Magnetoresistance). GMR allows and micro-head to write and read the tiniest magnetic domains on the rapidly spinning disk. GMR now makes it possible to store over 20 million bits per square inch, the equivalent of 2,500 books, considerably higher than CD-ROM density. This paper will describe GR and GMR principles and how they are used. Head construction will be discussed along with fabrication processes that utilize semiconductor technology. The production process now requires reworkable adhesives that were recently developed for this fascinating application. We will cover both wafer processing and head element fabrication using thermoplastic adhesives.