Selective chemical removal of coil seed-layer in thin film head

Details Selective chemical removal of coil seed-layer in thin film head Selective chemical removal of coil seed-layer in thin film head

1990-09-28

1991-10-22

Powell, William A.

Adhesive bonding and miscellaneous chemical manufacture

Delaminating processes adapted for specified product

Delaminating in preparation for post processing recycling step

29603, 156656, 1566591, 360123, B44C 122, C23F 102

Patent

active

050592785

ABSTRACT:
The seed-layer, or metallization layer, used to form the coil winding in a thin film head (TFH) by electrodeposition, is removed from between individual winding turns by selective etching with an etchant which preferentially, or selectively, attacks the seed-layer while leaving the coil winding, insulation, and gap materials essentially intact. A suitable combination of compatible materials which can be used as the seed-layer, coil winding, and etchant, respectively, in practicing this invention comprises nickel-iron Permalloy, copper, and a mixture of nitric acid and phosphoric acid diluted in pure water. Other combinations of materials and types of etching processes suitable for this invention are also disclosed.

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