Method for manufacturing a magnetic memory element array using high angle side etch to open top electrical contact
A method for manufacturing a magnetic memory element array. A plurality of magnetic memory elements are formed on a substrate, and a dielectric fill layer such as SiO2 or SiNx is deposited over the magnetic memory element pillars. An ion milling is then performed at a high angle (at least 70 degrees) relative normal to remove topographic dielectric features from areas over the magnetic memory elements. Optionally, additional ion milling processes can be performed at increasing angles relative to normal until the dielectric material has been removed from the areas over the magnetic memory elements.
1. A method for manufacturing high density pillar structures, the method comprising:
forming magnetic memory element pillars over a substrate;
depositing a dielectric material over the magnetic memory element pillars and substrate;
performing a first high angle ion milling to remove a portion of the dielectric material, the high angle ion milling being performed at an angle of at least 70 degrees relative to normal with a rotating chuck; and
after performing the first ion milling, performing a second ion milling at an angle relative to normal that is greater than the angle of the first ion milling.
2. The method as in claim 1 , further comprising performing sequential ion milling processes at increasing angles relative to normal.
3. The method as in claim 1 , wherein the magnetic memory element pillars are formed with a hard mask structure at their top, the method further comprising performing sequential ion milling processes at increasing angles relative to normal and terminating the ion milling when the hard mask has been exposed.
4. The method as in claim 1 , wherein the dielectric material comprises one or more of SiO 2 , Si 3 N 4 , SiC or Al 2 O 3 .
5. The method as in claim 1 , wherein the dielectric material is deposited at least to the height of the top of the magnetic memory element pillars.
6. The method as in claim 1 , wherein the magnetic memory element pillars are formed with hard mask layers at their top and wherein the dielectric layer is deposited at least to the level of the hard mask layer.
7. The method as in claim 1 , wherein the forming of the magnetic memory element pillars further comprises:
depositing a magnetic memory element layer;
depositing a hard mask layer;
depositing a photoresist layer;
photolithographically patterning the photoresist layer to form a photoresist mask;
performing a reactive ion etching to transfer the image of the photoresist mask onto the hard mask; and
performing an ion milling to remove portions of the magnetic memory element that are not protected by the hard mask to form magnetic memory element pillars.
8. The method as in claim 7 , wherein the ion milling process used to form the magnetic memory element pillars is performed at one or more angles relative to normal to form vertical side walls on the magnetic memory element pillars.
9. A method for manufacturing high density pillar structures, the method comprising:
forming magnetic memory element pillars over a substrate, the memory element pillars having a hard mask layer formed at their top, the hard mask layer having an end point detection layer incorporated therein;
depositing a dielectric material over the magnetic memory element pillars and substrate;
performing a first high angle ion milling to remove a portion of the dielectric material, the high angle ion milling being performed at an angle of at least 70 degrees relative to normal with a rotating chuck; and
after performing the first ion milling performing a second ion milling at an angle relative to normal that is greater than the angle of the first ion milling.
10. The method as in claim 9 , wherein the end point detection layer comprises Mg.
11. The method as in claim 9 , further comprising performing sequential ion milling processes at increasing angles relative to normal.
12. The method as in claim 9 , further comprising performing sequential ion milling processes at increasing angles relative to normal and terminating the ion milling when the end point detection layer has been detected.
13. The method as in claim 9 , further comprising after performing the ion milling performing a second ion milling at an angle relative to normal that is greater than the angle of the first ion milling, and terminating the second ion milling when the end point detection layer has been detected.
14. The method as in claim 9 , further comprising terminating the ion milling process when the end point detection layer has been detected, the end point detection layer being detected by secondary ion mass spectroscopy.
15. The method as in claim 9 , wherein the dielectric material comprises one or more of SiO 2 , Si 3 N 4 , SiC or Al 2 O 3 .
16. The method as in claim 9 , wherein the dielectric material is deposited at least to the height of the top of the magnetic memory element pillars.
17. The method as in claim 9 , wherein the dielectric layer is deposited at least to the level of the hard mask layer.
18. The method as in claim 9 , wherein the forming of the magnetic memory element pillars further comprises:
depositing a magnetic memory element layer;
depositing the hard mask layer;
depositing a photoresist photoreisist layer;
photolithographically patterning the photoresist layer to form a photoresist mask;
performing a reactive ion etching to transfer the image of the photoresist mask onto the hard mask; and
performing an ion milling to remove portions of the magnetic memory element that are not protected by the hard mask to form magnetic memory element pillars.