Method for manufacturing an ultra narrow gap magnetoresistive sensor
View Patent ↗A method for manufacturing a magnetoresistive sensor that decreases the stack height of the sensor. The method includes forming a sensor structure having at its top, a Ru layer and a Ta layer over the Ru layer. An annealing process is performed to set the magnetization of the pinned layer of the sensor structure. After the annealing process has been completed and the Ta layer is no longer needed, an ion milling process is performed to remove the Ta layer.
1. A method for manufacturing a magnetoresistive sensor, comprising:
providing a substrate;
depositing a plurality of sensor layers over the substrate, the plurality of sensor layers including a capping layer structure formed at the top of the plurality of sensor layers, the capping layer including a layer of Ru and a layer of Ta formed over the layer of Ru;
performing an annealing process;
after performing the annealing process, performing an ion milling to remove all of the layer of Ta; and
after performing the ion milling to remove all of the layer of Ta, defining a sensor structure from the plurality of sensor layers.
2. The method as in claim 1 wherein the Ta layer is deposited to a thickness of 1-5 nm.
3. The method as in claim 1 wherein the Ta layer is deposited to a thickness of 1-5 nm and the Ru layer is deposited to a thickness of 5-15 nm.
4. The method as in claim 1 wherein the Ta layer is deposited to a thickness of about 3 nm.
5. The method as in claim 1 wherein the Ta layer is deposited to a thickness of about 3 nm and the Ru layer is deposited to a thickness of about 10 nm.
6. The method as in claim 1 wherein an end point detection method is used during the ion milling to determine when the layer of Ta has been removed and is terminated after the Ta has been removed.
7. The method as in claim 1 wherein Secondary Ion Mass Spectroscopy is used during ion milling to determine when the layer of Ta has been removed, and the ion milling is terminated after the layer of Ta has been removed.
8. The method as in claim 1 wherein the ion milling removes the Ta layer and a portion of the Ru layer.
9. The method as in claim 1 wherein the ion milling removes the Ta layer and about 2 nm of the Ru layer.
10. The method as in claim 1 further comprising, after performing an ion milling to remove the layer of Ta, and after defining the sensor structure, depositing an electrically insulating gap layer.
11. The method as in claim 1 further comprising, after performing an ion milling to remove the layer of Ta, and after defining the sensor structure, depositing an electrically conductive lead layer.