Phase-change memory

1. A phase-change memory, comprising:

a plurality of phase-change structures, wherein each phase-change structure comprises:

a strip of phase-change material; and

a metal conductive strip on a top surface of the strip of phase-change material;

a first insulator made of a first insulating material on sides of the metal conductive strips and the strips of phase-change material;

a second insulator made of a second insulating material positioned in contact with and between first insulators of adjacent phase-change structures, said second insulating material being different from the first insulating material;

wherein top surfaces of the strips of phase-change material, first insulator and second insulator are coplanar;

an etch stop layer on the coplanar top surfaces of the metal conductive strips, the first insulator and the second insulator, wherein the etch stop layer is made of a third insulating material different from the first and second insulating materials;

wherein the etch stop layer includes openings extending through the etch stop layer to the top surfaces of the metal conductive strips; and

a metal connection structure filling each opening; and

wherein the third insulating material is selectively etchable with respect to both the first and second insulating materials.

2. The phase-change memory of claim 1 , wherein the metal connection structure is a component of a connection network composed of several levels of metallization.

3. The phase-change memory of claim 1 , wherein the metal connection structure comprises: a metal liner layer lining side walls and a bottom of each opening; and a metal fill in contact with the metal liner layer.

4. The phase-change memory of claim 3 , wherein the metal liner layer is a cladding made of tantalum nitride and the metal fill is a core made of copper.

5. The phase-change memory of claim 1 , wherein said first insulating material is silicon nitride and said second insulating material is silicon oxide.

6. The phase-change memory of claim 5 , wherein said third insulating material is selected from the group consisting of AlN and Al 2 O 3 .

7. The phase-change memory of claim 1 , wherein the strip of phase-change material has a width and further has a length longer than the width, and wherein the metal conductive strip has a width and further has a length longer than the width, and wherein the widths of the strip of phase-change material and metal conductive strip are the same.

8. A method of fabricating a phase-change memory, comprising:

forming a plurality of phase-change structures, wherein each phase-change structure comprises a conductive strip that covers a strip of phase-change material;

insulating the phase-change structures from each other with a first insulator made of a first insulating material on sides of the conductive strips and the strips of phase-change material and a second insulator made of a second insulating material positioned in contact with and between first insulators of adjacent phase-change structures, said second insulating material being different from the first insulating material;

planarizing the conductive strips, first insulator and second insulator to form a coplanar surface;

depositing an etch-stop layer on the coplanar surface, wherein the etch stop layer is made of a third insulating material different from the first and second insulating materials, the third insulating material being selectively etchable with respect to both the first and second insulating materials;

etching openings through the etch stop layer to uncover upper faces of the conductive strips; and

forming elements of a lower metallization level of a connection network within the etched openings, in direct contact with upper faces of the conductive strip.

9. The method according to claim 8 , wherein forming elements of the lower metallization level comprises: filling the etched openings with one or more metal materials.

10. The method according to claim 9 , wherein filling the etched openings comprises depositing a cladding made of tantalum nitride and depositing a core made of copper.

11. The method according to claim 8 , wherein the first insulating material is silicon nitride, the second insulating material is silicon oxide and the etch-stop layer is made of a material selected from the group consisting of Al 2 O 3 and AlN.

12. The method according to claim 8 , wherein a thickness of the etch-stop layer is in a range between 5 and 10 nm.