Thin film magnetic head and method of manufacturing the same

A method of manufacturing a combination type thin film magnetic head having an inductive type thin film magnetic head supported by a substrate comprising the steps of:

• forming a first magnetic layer extending forwardly beyond an air bearing surface such that the first magnetic layer is supported by the substrate;
• forming an insulating layer made of an inorganic insulating material on a surface of said first magnetic layer such that the insulating layer extends at least from the air bearing surface and includes a -shaped cut-out portion whose inner edge defines a reference position of throat height zero;
• forming a write gap layer to cover an exposed surface of said first magnetic layer and a surface of said inorganic insulating layer;
• forming a thin film coil on a surface of a portion of said write gap layer provided on said insulating layer in an insulated and isolated manner;
• forming a second magnetic layer on at least a part of a surface of the write gap layer exposed within said cut-out portion of the inorganic insulating layer and on a surface of said thin film coil, said second magnetic layer being magnetically coupled with said first magnetic layer at a rear portion remote from the air bearing surface;
• etching an exposed portion of the write gap layer within the cut-out portion to expose an underlying surface of the first magnetic layer, while a portion of said second magnetic layer provided within the cut-out portion and said inorganic insulating layer are used as a mask;
• etching a surface of a portion of said first magnetic layer exposed within said cut-out portion of the insulating layer over a part of a thickness of the first magnetic layer to form a trim structure, while said portion of said second magnetic layer provided within the cut-out portion and said inorganic insulating layer are used as the mask;
• covering a whole surface with an overcoat layer;
• and
• polishing the air bearing surface such that at least a front end of said cut-out portion of the insulating layer is exposed, while said inner edge of the cut-out portion is used as a positional reference.