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Directionally Homogenous Magnets for Vacuum Deposition Apparatus

IP.com Disclosure Number: IPCOM000086763D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Jones, RE: AUTHOR [+3]

Abstract

Magnetic films which are useful for memories and film heads require a uniaxial anisotropy, which can be provided by vacuum deposition in the presence of a magnetic field. The field should be directionally homogeneous over the substrate area. In the past, this field has been generally supplied by a large pair of Helmholtz coils located outside the vacuum chamber. Large currents and water cooling are necessary for these coils. Therefore, they suffered from high initial installation and maintenance cost. Furthermore, the target in a sputtering system could be of a magnetic material and, therefore, could disturb the original field distribution in such a way that the field applied to the substrate becomes very small unless the target is very thin.

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Directionally Homogenous Magnets for Vacuum Deposition Apparatus

Magnetic films which are useful for memories and film heads require a uniaxial anisotropy, which can be provided by vacuum deposition in the presence of a magnetic field. The field should be directionally homogeneous over the substrate area. In the past, this field has been generally supplied by a large pair of Helmholtz coils located outside the vacuum chamber. Large currents and water cooling are necessary for these coils. Therefore, they suffered from high initial installation and maintenance cost. Furthermore, the target in a sputtering system could be of a magnetic material and, therefore, could disturb the original field distribution in such a way that the field applied to the substrate becomes very small unless the target is very thin.

To solve these problems, a compact permanent-magnet structure with configurations similar to the ones shown in the figures can be used to generate a field which is directionally homogeneous over the area of the substrate holder. The structure in Fig. A uses two permanent bar magnets 1 and 2 and four magnetically soft blocks 3-6. Blocks 3 and 4 are shaped to obtain directional homogeneity within the area between the two dotted lines 7 and 8. Blocks 5 and 6 are inserted to shortcircuit the flux close to the permanent magnets 1 and 2, and thus extend the useful area beyond the dotted lines 7 and 8, respectively.

The structure in Fig. B makes use of the homogeneous...