Method of manufacturing a thermally-assisted magnetic recording head that suppresses protrusion of a plasmon generator

1. A method of manufacturing a thermally-assisted magnetic recording head, the thermally-assisted magnetic recording head comprising: a medium facing surface that faces a magnetic recording medium; a magnetic pole; a waveguide; and a plasmon generator, wherein:

the magnetic pole produces a write magnetic field for writing data on the magnetic recording medium;

the waveguide includes a core through which light propagates, and a cladding that surrounds the core, the core having an evanescent light generating surface that generates evanescent light based on the light propagating through the core;

the plasmon generator has an outer surface that includes a plasmon exciting part and a front end face, the plasmon exciting part facing the evanescent light generating surface with a predetermined spacing therebetween, the front end face being located in the medium facing surface and including a near-field light generating part that generates near-field light; and

the plasmon generator is configured so that a surface plasmon is excited on the plasmon exciting part through coupling with the evanescent light generated from the evanescent light generating surface, the surface plasmon propagates to the near-field light generating part, and the near-field light generating part generates the near-field light based on the surface plasmon,

the method comprising the steps of:

forming a preliminary head section that has a surface to be polished and includes the magnetic pole, the waveguide, and a preliminary plasmon generator;

causing a volumetric expansion of the preliminary plasmon generator with heat by introducing light into the core of the waveguide of the preliminary head section; and

polishing the surface to be polished of the preliminary head section into the medium facing surface, wherein

the preliminary plasmon generator has an end face that is located in the surface to be polished, and

in the step of polishing the surface to be polished, the surface to be polished is subjected to polishing with the preliminary plasmon generator expanded in volume, whereby the end face of the preliminary plasmon generator is polished into the front end face, and the preliminary plasmon generator thereby becomes the plasmon generator.

2. The method of manufacturing the thermally-assisted magnetic recording head according to claim 1 , wherein, in the step of causing a volumetric expansion of the preliminary plasmon generator, the preliminary plasmon generator is made to have a temperature of 400° C.

3. The method of manufacturing the thermally-assisted magnetic recording head according to claim 1 , wherein the plasmon generator is formed of one of Au, Ag, and Cu.