Copper damascene chemical mechanical polishing (CMP) for thin film head writer fabrication

A method of forming at least one coil layer in a write head comprising:

• depositing a first insulating layer on top of a magnetic alloy layer;
• forming hard baked photoresist on top of the deposited first insulating layer;
• filling a second insulating layer on top of the hard baked photoresist;
• polishing back the filled second insulating layer;
• depositing a dielectric hard mask on top of the formed hard baked photoresist layer;
• etching trenches through a plurality of layer stacks, each made of the dielectric hard mask and the hard bake photoresist defining coil turns;
• depositing a barrier layer on top plurality of layer stacks and the bottom and sidewalls of the trenches;
• depositing a copper seed layer on top of the barrier layer;
• electroplating the trenches with copper wherein some of the electroplated copper forms a first coil layer and the remainder of the filled copper is undesirable;
• performing a two-slurry step of chemical mechanical polishing with a first slurry step removing the undesirable copper that is on top of the barrier layer and on top of the trenches and a second slurry step removing the remainder of the undesirable copper, the barrier layer, the copper seed layer, the hard mask, the hard basked photoresist layer, the magnetic alloy layer, and the second insulating layer using a combination of a particular pH, oxidizer and corrosion inhibitor, wherein the corrosion inhibitor is bencotriazole (BTA) and the oxidizer is ammonium persulfate (APS) and further wherein the combination is SiO2/BTA/APS and the concentrations of the combination is:
• SiO2/BTA/APS Slurry:
• SiO2 150 nm, 10%+Benzotriazole (BTA) 0.0002% to 0.2%+Ammonium Persulfate (APS) 0.02% to 2%+DI water-pH 8 to 12 (KOH).

A method of forming at least one coil layer in a write head of a disc drive comprising:

• depositing a first insulating layer on top of a magnetic alloy layer;
• forming hard baked photoresist on top of the deposited first insulating layer;
• filling a second insulating layer on top of the hard baked photoresist and polishing back;
• depositing a dielectric hard mask on top of the hard baked photoresist layer;
• etching trenches through a plurality of layer stacks, each made of the dielectric hard mask and the hard bake photoresist defining coil turns;
• depositing a barrier layer is on top plurality of layer stacks and the bottom and sidewalls of the trenches;
• depositing a copper seed layer on top of the barrier layer;
• electroplating the trenches with copper wherein some of the electroplated copper forms a first coil layer and the remainder of the filled copper is undesirable;
• performing a two-slurry step of chemical mechanical polishing with a first slurry step removing the undesirable copper that is on top of the barrier layer and on top of the trenches using a composition of AbOQ˜/BTA/H202 Slurry having a concentration of 19 A1203150 nm, 3%+Benzotriazole (BTA) 0.0002% to 0.2%+H2021% to 20%, +DI water with a pH of 2 to 6 and a second slurry step removing the remainder of the undesirable copper, the barrier layer, the seed layer, the hard mask, the hard baked photoresist layer the magnetic alloy layer, and alumina insulating layer.