Methods for fabricating damascene write poles using ruthenium hard masks
A method for forming a write pole comprises the steps of providing a structure comprising a substrate layer, a ruthenium layer over the substrate layer, and a tantalum layer over the ruthenium layer, providing an opening in the tantalum layer over a portion of the ruthenium layer, performing a first reactive ion etching step on the portion of the ruthenium layer under the opening in the tantalum layer to provide an opening in the ruthenium layer over a portion of the substrate layer, performing a second reactive ion etching step on the portion of the substrate layer under the opening in the ruthenium layer to form a damascene trench therein, and filling the damascene trench with a magnetic material to form the write pole.
1. A method for forming a write pole, comprising the steps of:
providing a structure comprising a substrate layer, a ruthenium layer over the substrate layer, and a tantalum layer over the ruthenium layer;
providing an opening in the tantalum layer over a portion of the ruthenium layer;
performing a first reactive ion etching step on the portion of the ruthenium layer under the opening in the tantalum layer to provide an opening in the ruthenium layer over a portion of the substrate layer;
performing a second reactive ion etching step on the portion of the substrate layer under the opening in the ruthenium layer to form a damascene trench therein; and
filling the damascene trench with a magnetic material to form the write pole.
2. The method according to claim 1 , wherein the first reactive ion etching step comprises reactive ion etching with a first gas comprising both chlorine (Cl) and oxygen (O).
3. The method according to claim 1 , wherein the second reactive ion etching step comprises reactive ion etching with a second gas comprising chlorine (Cl).
4. The method according to claim 1 , wherein the opening in the tantalum layer is provided by:
forming a photoresist pattern over the tantalum layer, the photoresist pattern including an opening over a portion of the tantalum layer, and
performing a third reactive ion etching step on the portion of the tantalum layer under the opening in the photoresist pattern to provide the opening in the tantalum layer.
5. The method according to claim 4 , wherein the third reactive ion etching step comprises reactive ion etching with a third gas comprising Cl.
6. The method according to claim 4 , wherein the photoresist pattern comprises a layer of photoresist material in which the opening is disposed, and a bar layer disposed between the layer of photoresist material and the tantalum layer.
7. The method according to claim 6 , wherein the bar layer comprises a nitride.
8. The method according to claim 1 , wherein the opening in the tantalum layer is provided by:
forming a photoresist pattern over the ruthenium layer, the photoresist pattern including a region of photoresist over the portion of the ruthenium layer,
disposing the tantalum layer over the photoresist pattern; and
etching the tantalum layer to remove both a portion of the tantalum layer over the region of photoresist and the region of photoresist.
9. The method according to claim 8 , wherein the photoresist pattern comprises an iso-line of photoresist material comprising the region of photoresist, and a bar layer disposed between the iso-line of photoresist material and the tantalum layer.
10. The method according to claim 9 , further comprising etching an exposed portion of the bar layer before disposing the tantalum layer over the photoresist pattern.
11. The method according to claim 1 , wherein the substrate layer comprises alumina.
12. The method according to claim 1 , wherein the structure further comprises a stop layer under the substrate layer.
13. The method according to claim 12 , wherein the stop layer comprises NiCr, Cr or Ru.
14. The method according to claim 1 , wherein the structure further comprises a second layer of tantalum between the substrate layer and the ruthenium layer, and wherein the second reactive ion etching step provides an opening in the second tantalum layer under the opening in the ruthenium layer.
15. The method according to claim 1 , wherein the step of filling the damascene trench with the magnetic material comprises electroplating the magnetic material.
16. The method according to claim 1 , further comprising the step of polishing the magnetic material to remove a portion thereof extending above the damascene trench.
17. The method according to claim 16 , wherein the polishing is stopped upon reaching the ruthenium layer.