GB1497575A - Magnetic heads - Google Patents

Abstract

1497575 Magnetic heads PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 21 May 1975 [24 May 1974] 21801/75 Heading G5R A playback magnetic head comprises a substrate 1, Fig. 3, bearing a magnetic flux-sensitive element in the form of a thin film 4, on only one side-wall 6, Fig. 4 (not shown), of a groove 2 extending in a major surface of the substrate, and electrical leads (not shown) connected to the flux-sensitive element. The head is made by etching the groove 2 in a substrate 1 of sapphire or a carbide, or silicon, the latter allowing the groove side-walls to be normal to the major surface. An auxiliary layer 3 of Al or Cu, 500 to 10,000 Angstroms thick is then vapour deposited at a first angle (α), Fig. 2 (not shown), to the substrate major surface onto areas thereof at both sides of groove 2 and onto a first sidewall 5 thereof, a 1000 Angstrom thick layer 4 of magnetic flux-sensitive material, such as magnetoresistive Ni-Fe, being thereafter vapour deposited at a second angle # to the substrate onto the areas shown in Fig. 3. The auxiliary layer 3, and the parts of layer 4 thereon, are then removed by etching leaving only the part of layer 4 on a second side-wall 6 of groove 2, to which layer 4 electrical leads are then connected. This method produces a magnetoresistive element 4 with an accurately defined height (h), Fig. 4 (not shown), e.g. of 5Œ 0À5 microns, without the need for grinding the substrate major surface, height (h) being dependent on the angle # and the location of edge 7. The method may be used to form a magnetoresistive element on the outer side-wall 11, Fig. 5, of the central web of a generally U-shaped groove 8, a lacquer layer 10 then being provided to cover the groove part between lines C and D. The remaining part of the groove 8 outward of lines C and D is then filled up to the major surface of the substrate with Au which contacts the magnetoresistive element and which is connected at E and F to an external circuit by "bean leads" or a "plated through hole" technique. The part of groove 8 between C and D may be filled with SiO.