Method of forming main pole of thermally-assisted magnetic recording head

A method of manufacturing a thermally-assisted magnetic recording head, the thermally-assisted magnetic recording head comprising:

• a medium facing surface that faces a recording medium;
• a main pole that produces a write magnetic field for writing data on the recording medium;
• an accommodation layer including an accommodation part that accommodates the main pole;
• a waveguide having a core and a clad, the core allowing light to propagate therethrough;
• a plasmon generator having a near-field light generating part located in the medium facing surface, the plasmon generator being configured so that a plasmon is excited based on the light propagating through the core, and the near-field light generating part generates near-field light based on the plasmon;
• and
• a substrate having a top surface, wherein:
• the main pole, the accommodation layer, the waveguide, and the plasmon generator are disposed above the top surface of the substrate;
• the core has an end face that faces toward the medium facing surface and that is located away from the medium facing surface, the core being located farther from the top surface of the substrate than is the plasmon generator;
• the main pole has a front end face located in the medium facing surface and a rear end face opposite to the front end face, the main pole being interposed between the end face of the core and the medium facing surface;
• the accommodation layer has a wall face that faces the accommodation part and that defines the shape of the rear end face of the main pole;
• and
• the front end face of the main pole has a first end closer to the top surface of the substrate and a second end farther from the top surface of the substrate, the first end being smaller than the second end in width in a track width direction,
• the method of manufacturing the thermally-assisted magnetic recording head comprising the steps of:
• forming the plasmon generator;
• forming the waveguide after the plasmon generator is formed;
• and
• forming the accommodation layer and the main pole after the plasmon generator is formed,
• wherein the step of forming the accommodation layer and the main pole includes:
• a step of forming an initial accommodation layer having a top surface;
• a step of forming a first etching mask on the top surface of the initial accommodation layer, the first etching mask having a first opening;
• a first etching step of etching the initial accommodation layer by reactive ion etching using the first etching mask to thereby form a groove in the initial accommodation layer;
• a step of forming a second etching mask on the top surface of the initial accommodating layer after the first etching step, the second etching mask having a second opening;
• a second etching step of etching a part of the initial accommodation layer including the groove by reactive ion etching using the second etching mask so that the initial accommodation layer becomes the accommodation layer and the groove becomes the accommodation part;
• and
• a step of forming the main pole in the accommodation part, wherein:
• the first etching mask has first and second sidewalls that face the first opening, the first and second sidewalls being opposed to each other and being at a first distance from each other in the track width direction;
• the second etching mask has third and fourth sidewalls that face the second opening, the third and fourth sidewalls being opposed to each other and being at a second distance from each other in the track width direction, the second distance being greater than the first distance;
• and
• in any cross section of the accommodation part parallel to the medium facing surface, an end closest to the top surface of the substrate is smaller in width in the track width direction than an end farthest from the top surface of the substrate.