Method for making a perpendicular magnetic recording write head with write pole having thin side gaps and thicker leading gap
Ionized physical vapor deposition (IPVD) is used to form a magnetic recording disk drive write head main pole with thin side gap layers and a thicker leading gap layer. A metal or metal alloy is formed by IPVD in a trench with a bottom and outwardly sloping sidewalls. An optional Ru seed layer is deposited on the metal or metal alloy. This is followed by atomic layer deposition (ALD) of a Ru smoothing layer. If the IPVD results in metal or metal alloy side gap layers with a rough surface, the ALD process is modified, resulting in a smooth Ru smoothing layer that does not replicate the rough surface of the side gap layers.
1. A method for depositing a layer of material in a substrate having a trench with a bottom and outwardly sloped sidewalls comprising:
depositing into the trench, by ionized physical vapor deposition, material selected from a metal and a metal alloy to form a bottom layer of said material and sidewall layers of said material, wherein said sidewall layers are thinner than said bottom layer;
depositing a seed layer of ruthenium (Ru) on said bottom layer and said sidewall layers; and
depositing a smoothing layer of Ru on said Ru seed layer by atomic layer deposition using RuO 4 and H 2 , wherein the RuO 4 acts as a precursor that reduces to RuO 2 on said Ru seed layer and the H 2 acts to reduce RuO 2 to Ru.
2. The method of claim 1 wherein said material is selected from a NiNb alloy, a NiTa alloy and a NiCr alloy.
3. The method of claim 1 wherein the thickness of said bottom layer is at least 1.5 times as thick as the thickness of said sidewall layers.
4. The method of claim 1 wherein said sidewall layers have a surface substantially rougher than the surface of said bottom layer, wherein the Ru seed layer substantially replicates the surface of said sidewall layers, and further comprising, after the RuO 2 has formed on the Ru seed layer, continuing to introduce RuO 4 .
5. The method of claim 1 wherein said sidewall layers have a surface substantially rougher than the surface of said bottom layer, wherein the Ru seed layer substantially replicates the surface of said sidewall layers, and further comprising, after the RuO 2 has formed on the Ru seed layer, delaying the introduction of H 2 .
6. The method of claim 1 further comprising depositing a metallic pole seed layer comprising Co and Fe on the Ru smoothing layer and electroplating a ferromagnetic pole layer comprising Co and Fe on the pole seed layer.
7. A method for forming a main pole of a magnetic recording disk drive write head comprising:
providing a substrate having a trench with a bottom and outwardly sloped sidewalls;
depositing into the trench, by ionized physical vapor deposition, material selected from a nonmagnetic metal and a nonmagnetic metal alloy to form a bottom layer of said material and sidewall layers of said material, said sidewall layers having a thickness and said bottom layer is having a thickness at least 1.5 times the thickness of said sidewall layers;
depositing a seed layer of ruthenium (Ru) on said bottom layer and said sidewall layers;
depositing a smoothing layer of Ru on said Ru seed layer by atomic layer deposition using RuO 4 and H 2 , wherein the RuO 4 acts as a precursor that reduces to RuO 2 on said Ru seed layer and the H 2 acts to reduce RuO 2 to Ru;
depositing a metallic pole seed layer comprising Co and Fe on the Ru smoothing layer; and
electroplating a ferromagnetic pole layer comprising Co and Fe on the pole seed layer.
8. The method of claim 7 wherein said material is selected from a NiNb alloy, a NiTa alloy and a NiCr alloy.
9. The method of claim 7 wherein said sidewall layers have a surface substantially rougher than the surface of said bottom layer, wherein the Ru seed layer substantially replicates the surface of said sidewall layers, and further comprising, after the RuO 2 has formed on the Ru seed layer, continuing to introduce RuO 4 .
10. The method of claim 7 wherein said sidewall layers have a surface substantially rougher than the surface of said bottom layer, wherein the Ru seed layer substantially replicates the surface of said sidewall layers, and further comprising, after the RuO 2 has formed on the Ru seed layer, delaying the introduction of H 2 .
11. The method of claim 7 wherein providing a substrate comprises providing a substrate formed of ferromagnetic material selected from alloys of two or more of Ni, Fe and Co.
12. A method for depositing a layer of material in a substrate having a trench with a bottom and outwardly sloped sidewalls comprising:
depositing into the trench, by ionized physical vapor deposition, material selected from a metal and a metal alloy to form a bottom layer of said material and sidewall layers of said material, wherein said sidewall layers are thinner than said bottom layer;
depositing a smoothing layer of Al 2 O 3 on said bottom layer and said sidewall layers by atomic layer deposition, said Al 2 O 3 smoothing layer having a thickness greater than or equal to 1 nm and less than 5 nm; and
depositing a metallic pole seed layer comprising Co and Fe on the Al 2 O 3 smoothing layer and electroplating a ferromagnetic pole layer comprising Co and Fe on the pole seed layer.