METHOD TO MAKE INTERFEROMETRIC TAPER WAVEGUIDE FOR HAMR LIGHT DELIVERY
A method for making an interferometric taper waveguide (I-TWG) with high critical dimension uniformity and small line edge roughness for a heat assisted magnetic recording (HAMR) head, wherein the method includes creating an I-TWG film stack with two hard mask layers on top of an I-TWG core layer sandwiched between two cladding layers, defining a photoresist pattern over the I-TWG film stack using deep ultraviolet lithography, transferring the pattern to the first hard mask layer using reactive ion etching (RIE), forming a temporary I-TWG pattern on the second hard mask layer using RIE, transferring the temporary pattern to the I-TWG core using RIE, refilling the cladding layer, and planarizing using chemical mechanical planarization (CMP).
1 . A process for manufacturing a waveguide for magnetic recording media, the process comprising:
depositing a film stack, the film stack comprising a first hard mask layer, a second hard mask layer, a first cladding layer, a core layer, and a second cladding layer;
defining a first pattern in a photoresist layer;
transferring the first pattern to the first hard mask layer;
removing the photoresist layer;
forming a second pattern in the second hard mask layer patterned from the first pattern in the first hard mask layer;
transferring the second pattern to the core layer;
planarizing a top surface of the waveguide; and
integrating the waveguide with magnetic recording media components.
2 . The process of claim 1 wherein the core layer is deposited on the second cladding layer, the first cladding layer is deposited on the core layer, the second hard mask layer is deposited on the first cladding layer, and the first hard mask layer is deposited on the second hard mask layer.
3 . The process of claim 1 wherein the first hard mask layer comprises Ta 2 O 5 or Ta, the second hard mask layer comprises Cr or Ru, the first cladding layer comprises SiO 2 , the core layer comprises Ta 2 O 5 , and the second cladding layer comprises SiO 2 .
4 . The process of claim 1 wherein the defining a first pattern in the photoresist comprises ultraviolet lithography.
5 . The process of claim 1 wherein the transferring the first pattern to the first hard mask layer comprises reactive ion etching.
6 . The process of claim 1 wherein the forming the second pattern in the second hard mask layer comprises reactive ion etching.
7 . The process of claim 1 wherein the transferring the second pattern to the core layer comprises reactive ion etching, which results in the removal of cladding material.
8 . The process of claim 7 further comprising refilling the cladding material removed by the reactive ion etching.
9 . The process of claim 1 wherein the planarizing a top surface of the waveguide comprises chemical mechanical planarizing.
10 . The process for a manufacturing waveguide of claim 1 further comprising removing the second hard mask layer using wet etching.