Thin film head

Figure 6 Scanning Karr image of the magnetization changes in the indirection for a thin-film head having a 1-MHz, 5-mA p-p coil current, and the magnetic domain pattern deduced for this head from the observed domain wall motion. ...

Metal in gap (MIG) or ferrite heads are produced with a combination of machining, bonding, and thin-film processes. Thin-film inductive heads are manufactured using thin-fihn processes similar those of semiconductor 1C technology (discussed in Chapter 19). The thin-film head production process is rather unusual, as it involves both very thin and very thick films. We choose to present here a detailed summary of the fabrication process of thin-film inductive heads with a single-layer spiral coil. This may serve, once again to, illustrate the centrally important role of electrochemical deposition in connection with modem information technology. 

Figure 20.4. Thin-film head fabrication stage 1. (From Ref. 1, by permission from Elsevier.)...

Substrates most commonly used for thin-film heads are ceramic alumina TiC wafers. The production steps are as follows (see Figs 20.4 to 20.6 and Ref. 3) ... 

S. H. Liao, Electrodeposition of Magnetic Materials for Thin-Film Heads, IEEE TYans. on Mag., 26, No. 1, 328-332 (1990). 

Figure 12. Thin film head fabrication stages (1). Reprinted from Ref. 48, Copyright (1999) with permission from Elsevier.

Most thin-film inductive heads employ multilayer spiral coils to achieve large read back signals. This means that the copper plating and the hard cured photoresist steps must be repeated. Electrical coimection between the neighboring coil layers must also be implemented. Naturally, these steps greatly add to the complexity of the thin film head production. 

The process flow for the thin-film head is shown in Fig. 6.6 [6]. The Cu coils, Cu lead, Au pad, and the core of the soft magnetic thin films in the head are prepared by electrodeposition. These metal parts require a high-aspect ratio. Also, the method... 

Electroplated permalloy films for use as thin-film heads are based on the technology of magnetic wire memory developed in the 1950s. Ever since IBM applied the... 

Fig. 8.1 (a) Schematic illustration ol thin film head with a helical coil at the main pole tip. (b) Dependence of field distribution on coil recession height, h [2]. 1999 IEEE... 

These ion-beam systems have been used to manufacture superconducting films, thin film heads for electronic equipment, optical thin films, ring-laser gyro-mirrors, dielectric films of all... 

Further improvements in the frequency response of thin film heads have been investigated by preparing multilayered films with insulating (Si02) interlayers (Louis, Jeong Walser, 1990), or with heteroamorphous structures, where amorphous, magnetic nanoparticles ( 5 nm) are scattered... 

Thin film head by throngh-mask plating... 

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