Reactive ion beam etching method and a thin film head fabricated using the method

A process for ion beam etching of a substrate having a structure comprising a first layer and a second layer, said process comprising the steps of:

• generating in an ion source a plasma including a species capable of forming carbonaceous deposits in said ion source;
• impinging an ion beam extracted from said plasma onto said substrate to selectively etch said second layer at a rate greater than about two times the rate of etching said first layer, said ion beam having species that chemically react with a material included in said second layer;
• and
• wherein said selectivity is substantially repeatable upon independent executions of said process.

A process for fabricating a thin film magnetic head, comprising the steps of:

• forming a structure comprising a lower magnetic pole layer, a gap layer overlying the lower magnetic pole layer, and a patterned upper magnetic pole layer over the gap layer;
• bombarding said structure with a first ion beam extracted from a first ion source, the first ion beam operative in etching the gap layer to expose a portion thereof;
• and
• bombarding said structure, including the portion of the gap layer exposed by etching the gap layer, with a second ion beam that includes an oxidizing species.

A process for ion beam etching of a substrate having a structure comprising a first layer and a second layer, said process comprising the steps of:

• generating in an ion source a plasma that includes a carbon-containing species;
• impinging an ion beam extracted from said plasma onto said substrate to selectively etch said second layer at a rate greater than about two times the rate of etching said first layer, said ion beam having species that chemically react with a material included in said second layer;
• and
• wherein said selectivity is substantially repeatable upon independent executions of said process.