Magnetic memory and manufacturing method thereof
View Patent ↗According to one embodiment, a magnetic memory is disclosed. The magnetic memory includes a substrate, and a contact plug provided on the substrate. The contact plug includes a first contact plug, and a second contact plug provided on the first contact plug and having a smaller diameter than that of the first contact plug. The magnetic memory further includes a magnetoresistive element provided on the second contact plug. The diameter of the second contact plug is smaller than that of the magnetoresistive element.
1. A magnetic memory comprising:
a substrate;
a contact plug provided on the substrate, the contact plug including a first contact plug, and a second contact plug provided on the first contact plug and having a smaller diameter than a diameter of the first contact plug, and the first and second contact plugs comprising a same material; and
a magnetoresistive element provided on the second contact plug, wherein the diameter of the second contact plug is smaller than a diameter of the magnetoresistive element.
2. The magnetic memory according to claim 1 , wherein an upper surface of the second contact plug is covered with the magnetoresistive element.
3. A magnetic memory comprising:
a substrate;
a contact plug provided on the substrate, the contact plug including a first contact plug, and a second contact plug provided on the first contact plug and having a smaller diameter than a diameter of the first contact plug, the first contact plug comprising a first material, and the second contact plug comprising a second material differing from the first material; and
a magnetoresistive element provided on the second contact plug, wherein the diameter of the second contact plug is smaller than a diameter of the magnetoresistive element.
4. The magnetic memory according to claim 3 , wherein the second material is lower in resistance than the first material.
5. The magnetic memory according to claim 3 , wherein the second material includes at least one of tantalum, silicon, titanium, copper, tungsten, aluminum, hafnium, boron, nickel, cobalt, and carbon nanotube.
6. A magnetic memory comprising:
a substrate;
a contact plug provided on the substrate, the contact plug including a first contact plug, and a second contact plug provided on the first contact plug and having a smaller diameter than a diameter of the first contact plug; and
a magnetoresistive element provided on the second contact plug, wherein the diameter of the second contact plug is smaller than a diameter of the magnetoresistive element,
wherein a side surface of the first contact plug is covered with a first insulating film, and a side surface of the second contact plug is covered with a second insulating film of a material differing from a material of the first insulating film.
7. The magnetic memory according to claim 6 , wherein the second insulating film includes an element constituting the second contact plug.
8. The magnetic memory according to claim 7 , wherein the second insulating film includes a nitrided or oxidized material of at least one of tantalum, silicon, titanium, copper, tungsten, aluminum, hafnium, boron, cobalt, and carbon nanotube.
9. The magnetic memory according to claim 6 , wherein the second contact plug has a hollow structure in which a hollow space is provided along a height direction.
10. The magnetic memory according to claim 9 , wherein the hollow structure is a hollow cylinder.
11. The magnetic memory according to claim 9 , wherein the first contact plug contacts the second contact plug at two points in a cross section of the first and second contact plugs taken along a plane defined by a normal direction which is perpendicular to a stacking direction of the first and second contact plugs.
12. The magnetic memory according to claim 6 , wherein the second contact plug includes an L-shaped portion.
13. The magnetic memory according to claim 6 , wherein the magnetoresistive element is a MTJ (Magnetic Tunnel Junction) element.
14. A method for manufacturing a magnetic memory comprising:
forming a first insulating film on a substrate;
forming a first contact plug in the first insulating film;
forming a second insulating film on the first insulating film;
forming a second contact plug connected to the first contact plug in the second insulating film, the second contact plug having a smaller diameter than a diameter of the first contact plug;
forming stacked films to be processed into a magnetoresistive element on the second contact plug and the second insulating film; and
forming the magnetoresistive element by processing the stacked films.
15. The method according to claim 14 , wherein the first and second insulating films comprise a same material.
16. A method for manufacturing a magnetic memory comprising:
forming a first insulating film on a substrate;
forming a first contact hole in the first insulating film;
filling the first contact hole with a first contact plug;
turning an upper part of the first contact hole into a trench unfilled with the first contact plug by removing an upper part of the first contact plug;
forming a second insulating film on a part of the first contact plug and forming a second contact hole which reaches the first contact plug and is surrounded by the second insulating film;
filling the second contact hole with a second contact plug;
forming stacked films to be processed into a magnetoresistive element on the second contact plug and the second insulating film; and
forming the magnetoresistive element by processing the stacked films.
17. The method according to claim 16 , wherein the first insulating film comprises a material differing from a material of the second insulating film.