Laminated plasmon generator with cavity process

A thermally assisted magnetic recording (TAMR) head comprising:

• (a) a write pole having a leading edge and a trailing edge formed along an air bearing surface (ABS), said leading edge and trailing edge are part of a leading side and trailing side, respectively, that are connected by two sides to define a cross-track width along each of the leading and trailing edges, the TAMR head including the write pole, a plasmon generator (PG) with planar top and bottom surfaces and sidewalls, and a waveguide move in a down-track direction over a magnetic medium during a write process;
• (b) the waveguide that captures light energy from a light source and propagates the light energy toward an end of the waveguide at the ABS, the waveguide has a top surface that faces the write pole and is separated from the planar bottom PG surface by a first gap distance;
• and
• (c) the PG that is formed between the waveguide and the write pole, the PG couples light energy from the waveguide to a surface plasmon mode along the planar bottom PG surface and sidewalls, the surface plasmon mode is propagated to an end of a peg portion of the PG at the ABS and is then projected as an optical spot onto a localized region of the magnetic medium thereby heating the localized region and reducing its magnetic coercivity and anisotropy to facilitate a write process, the PG has a plurality of non-planar layers each having a center section formed parallel to the planar bottom PG surface that is aligned in a plane that is perpendicular to the down-track direction, and side sections each formed parallel to a nearest PG sidewall, the plurality of non-planar PG layers comprises:
• (1) a plurality of “n” X layers where X is one of Au, Ag, Cu, Al, or alloys thereof with Co or Ni;
• and
• (2) a plurality of “n” or “n−1” Y layers where Y is a metal that is one of Ru, Cr, Pd, Pt, Ti, W, Ta, Mg, Fe, Co, Ni, Cu, Zr, Y, or a dielectric material that is one of Ta2O5, Al2O3, SiO2, SiON, Si3N4, Ti2O5, and HfO2 wherein X and Y layers are formed in an alternating design beginning with a first X layer at the bottom PG surface, and each X layer has a thickness that is greater than a thickness of an overlying Y layer.

A plasmon generator (PG) having a planar bottom surface and sidewalls that propagate light energy from a light source towards an air bearing surface (ABS) in a write head, a portion of the light energy is coupled to a surface plasmon mode along the sidewalls and the planar bottom surface of the PG, the surface plasmon mode is propagated to an end of a peg portion of the PG at the ABS and projected as an optical spot on a magnetic medium to provide localized heating during a write process, the PG comprises:

• (a) a first layer that includes the peg with an end at the ABS and a second end recessed from the ABS, the first and second ends are connected by two parallel sides extending in a lengthwise direction a first distance perpendicular to the ABS, and by a planar top surface formed parallel to the bottom PG surface, the first layer has a cross-track width, a first thickness in a down-track direction, and includes a plurality of non-planar layers each having a center section formed parallel to the planar bottom surface and side sections formed substantially parallel to a nearest PG sidewall, the first layer comprises;
• (1) a plurality of “n” X layers where X is one of Au, Ag, Cu, Al, or alloys thereof with Co or Ni;
• and
• (2) a plurality of “n” or “n−1” Y layers where Y is a metal that is one Ru, Cr, Pd, Pt, Ti, W, Ta, Mg, Fe, Co, Ni, Cu, Zr, Y, or a dielectric material that is one of Ta2O5, Al2O3, SiO2, SiON, Si3N4, Ti2O5, and HfO2 wherein X and Y layers are formed in an alternating manner beginning with a bottommost first X layer, and each X layer has a thickness that is greater than a thickness of an overlying Y layer;
• and
• (b) a second layer made of a noble metal that covers the planar top surface and two parallel sides of the first layer except over the peg portion, the second layer has a bottom surface that together with a bottom surface of the first metal layer form the planar bottom PG surface, and has sidewalls that are the PG sidewalls.

A thermally assisted magnetic recording (TAMR) head comprising:

• (a) a write pole having a leading edge and a trailing edge formed along an air bearing surface (ABS), said leading edge and trailing edge are part of a leading side and trailing side, respectively, that are connected by two sides to define a cross-track width along each of the leading and trailing edges, the TAMR head including the write pole, a plasmon generator (PG) with a planar bottom surface and sidewalls, and a waveguide move in a down-track direction over a magnetic medium during a write process;
• (b) the waveguide that captures light energy from a light source and propagates the light energy toward an end of the waveguide at the ABS, the waveguide has a top surface that faces the write pole and is separated from the planar bottom PG surface by a first gap distance;
• and
• (c) the PG that is formed between the waveguide and the write pole, the PG couples light energy from the waveguide to a surface plasmon mode along the planar bottom PG surface and sidewalls, the surface plasmon mode is propagated to a first end of a peg portion of the PG at the ABS and is then projected as an optical spot onto a localized region of the magnetic medium thereby heating the localized region and reducing its magnetic coercivity and anisotropy to facilitate a write process, the PG comprises:
• (a) a first layer that includes the peg portion having the first end at the ABS and a second end recessed from the ABS, the first and second ends are connected by two parallel sides extending in a lengthwise direction a first distance perpendicular to the ABS, and by a planar top surface formed parallel to the planar bottom PG surface, the first layer has a cross-track width, a first thickness in a down-track direction, and includes a plurality of non-planar layers each having a center section formed parallel to the planar bottom PG surface and side sections formed substantially parallel to a nearest PG sidewall, the first layer comprises
• (1) a plurality of “n” X layers where X is one of Au, Ag, Cu, Al, or alloys thereof with Co or Ni;
• and
• (2) a plurality of “n” or “n−1” Y layers where Y is a metal that is one of Ru, Cr, Pd, Pt, Ti, W, Ta, Mg, Fe, Co, Ni, Cu, Zr, Y, or a dielectric material that is one of Ta2O5, Al2O3, SiO2, SiON, Si3N4, Ti2O5, and HfO2 wherein X and Y layers are formed in an alternating design beginning with a first X layer at the planar bottom PG surface, and each X layer has a thickness that is greater than a thickness of an overlying Y layer;
• and
• (b) a second layer made of a noble metal that covers the planar top surface and two parallel sides of the first metal layer except over the peg portion, the second metal layer has a bottom surface that together with a bottom surface of the first layer form the planar bottom PG surface, and has sidewalls that are the PG sidewalls.

A method of fabricating a planar plasmon generator (PG) with a first down-track thickness in a TAMR head, comprising:

• (a) providing a dielectric layer on a substrate, and forming an opening in the dielectric layer with sidewalls and a planar bottom surface wherein a lengthwise dimension of the opening is in a direction perpendicular to a plane that will subsequently become the air bearing surface (ABS), a widthwise dimension is a cross-track direction, and the opening exposes a portion of the substrate;
• (b) depositing a first X layer having a thickness t1 on the planar bottom surface and sidewalls of the opening where X is one of Au, Ag, Cu, Al, or alloys thereof with Co or Ni;
• (c) depositing a first Y layer having a thickness h1 on the first X layer and where h1<t1, the first Y layer is a metal that is one of Ru, Cr, Pd, Pt, Ti, W, Ta, Mg, Fe, Co, Ni, Cu, Zr, Y, or a dielectric material that is one of Ta2O5, Al2O3, SiO2, SiON, Si3N4, Ti2O5, and HfO2;
• (d) repeating the X layer and Y layer deposition in alternating fashion until a plurality of “n” X layers, and a plurality of “n” or “n−1” Y layers are formed and completely fill the opening, each of the X layers has a thickness greater than a thickness of an overlying Y layer and each of the X and Y layers is non-planar with a center section formed parallel to the planar bottom surface and side sections that are substantially parallel to a nearest sidewall of the dielectric layer;
• and
• (e) performing a chemical mechanical polish (CMP) process to remove the X and Y layers formed above a top surface of the dielectric layer, the CMP process forms a laminated PG structure with a top surface that is coplanar with the dielectric layer top surface, and the PG comprises:
• (1) a peg portion with two parallel sidewalls aligned perpendicular to the ABS plane and that connect a first peg end at the ABS plane to a second peg end recessed toward a back side of the PG;
• and
• (2) a second portion with two sides that extend from the second peg end toward the back side of the PG and are separated by increasing distance in a cross-track direction with increasing distance from the second peg end.

A method of fabricating a plasmon generator in a TAMR head, comprising:

• (a) providing a first dielectric layer on a substrate, and forming a trench with sidewalls and a bottom surface in the first dielectric layer wherein a lengthwise dimension of the trench is in a direction perpendicular to a plane that will subsequently become the air bearing surface (ABS), and the trench exposes a portion of the substrate;
• (b) depositing a plurality of “n” non-planar X layers and “n” or “n−1” non-planar Y layers in alternating fashion on the sidewalls and the bottom surface to a level that fills the trench along a substantial portion thereof including a region at the ABS plane, each X layer is one of Au, Ag, Cu, Al, or alloys thereof with Co or Ni, and each Y layer is a metal that is one of Ru, Cr, Pd, Pt, Ti, W, Ta, Mg, Fe, Co, Ni, Cu, Zr, Y, or a dielectric material that is one of Ta2O5, Al2O3, SiO2, SiON, Si3N4, Ti2O5, and HfO2 wherein each X layer has a thickness that is greater than a thickness of an overlying Y layer;
• (c) performing a chemical mechanical polish (CMP) process to form a rod-like laminated layer with a planar top surface that is coplanar with a top surface of the dielectric layer, the rod-like laminated layer includes a peg portion with an end at the ABS plane with a first thickness in a down-track direction, and a width in a cross-track direction between two parallel sidewalls;
• (d) removing the first dielectric layer by an etch technique to leave the rod-like laminated layer on the substrate, the rod-like laminated layer has a rectangular shape from a top-down view wherein the two parallel sides connect a front end proximate to the ABS plane to a back end;
• (e) forming a photoresist layer on the rod-like laminated layer and then patterning to form an opening in a desired shape of a subsequently deposited second layer, the opening exposes a portion of the substrate along a substantial section of two parallel sides and back end of the rod-like laminated layer but the photoresist layer remains over the peg portion;
• (f) depositing the second layer made of a noble metal on exposed regions of the rod-like laminated layer and on exposed portions of substrate;
• and
• (g) removing the photoresist layer to leave a PG comprised of a rod-like laminated layer with an exposed peg portion, and the second layer with a first section formed above the top surface of the rod-like laminated layer and side portions formed along the two parallel sides that each have a bottom surface that is coplanar with a bottom surface of the rod-like laminated layer to form a planar bottom PG surface.