OMEGA-HEAD - AN EXPERIMENTAL 120-TURN INDUCTIVE HEAD

Experimental 120-turn thin-film inductive heads have been built. The k ey features of this head are the 6-mum pitch helical coils and an omeg a-shaped, planar yoke structure having dual easy axes. Hardbaked photo resist insulator layers are used to encapsulate the yoke and to smooth out the wafer surface topography. Micro-Kerr studies show that the ea sy axis remains in the transverse direction in the yokes after multipl e anneals. The P1/G/P2 is 3.8/0.3/3.8/mum, and the yoke length is clos e to 1 mm. The helical coils were built with a novel process that comb ines yoke/stud coplating and a photoresist planarization process. The coil resistance is 68OMEGA and the inductance is 5.5 muH. The yoke sat urates at 5 mA. The heads were tested over disks having Mrt of 2.5 mem u/cm2 and H(c) of 1500 Oe. The write threshold current is 5.3 mA (peak -to-peak) and the overwrite is 30 dB. The isolated pulse amplitude V(p p) is 10.3 muV/(T(w)V), where track width T(w) is in mum and the linea r velocity V in m/s.