Phase change memory device to prevent thermal cross-talk and method for manufacturing the same
View Patent ↗A phase change memory device for preventing thermal cross-talk includes lower electrodes respectively formed in a plurality of phase change cell regions of a semiconductor substrate. A first insulation layer is formed on the semiconductor substrate including to the lower electrodes having holes for exposing the respective lower electrodes. Heaters are formed on the surfaces of the respective holes to contact the lower electrodes. A second insulation layer is formed to fill the holes in which the heaters are formed. A mask pattern is then formed on the first and second insulation layers, including the heaters, to have openings that expose portions of the respective heaters having a constant pitch. A phase change layer is formed on the mask pattern including the exposed portions of the heaters and the first and second insulation layers and subsequently, upper electrodes are formed on the phase change layer.
1. A method for manufacturing a phase change memory device, comprising the steps of:
forming an interlayer dielectric on a semiconductor substrate;
etching the interlayer dielectric to form contact holes in a plurality of phase change cell regions of the semiconductor substrate;
forming lower electrodes respectively in the plurality of phase change cell regions of the semiconductor substrate;
forming a first insulation layer on the interlayer dielectric including the lower electrodes to have holes which expose the respective lower electrodes;
forming a material layer for heaters on the first insulation layer including the holes;
forming a second insulation layer on the material layer for heaters to fill the holes in which the material layer for heaters is formed;
polishing chemically and mechanically the second insulation layer and the material layer for heaters to expose the first insulation layer, and thereby forming heaters on surfaces of the holes to be brought into contact with the lower electrodes;
forming a mask pattern on the first and second insulation layers including the heaters to have openings which expose portions of the respective heaters and which have a constant pitch, wherein the openings are arranged to expose the heaters in a direction perpendicular to the cell arrangement direction;
forming a phase change layer on the mask pattern including the exposed portions of the heaters and the first and second insulation layers; and
forming upper electrodes on the phase change layer.
2. The method according to claim 1 , wherein the material layer for heaters is formed of any one of TiN, TiW and TiAlN.
3. The method according to claim 1 , wherein the material layer for heaters is formed through chemical vapor deposition or atomic layer deposition.
4. The method according to claim 1 , wherein the mask pattern is formed of a nitride layer.
5. The method according to claim 1 , wherein the mask pattern is formed in a manner such that side portions of the first and second insulation layers including the heaters are exposed in a lateral cell arrangement direction.
6. The method according to claim 1 , wherein the mask pattern is formed in a manner such that side portions of the first and second insulation layers including the heaters are exposed in a direction which is perpendicular to a cell arrangement direction.
7. The method according to claim 1 , wherein, after the step of forming the mask pattern and before the step of forming the phase change layer, the method further comprises the step of:
forming spacers on both sidewalk of each opening of the mask pattern.
8. The method according to claim 1 , wherein the upper electrodes are formed of any one of TiN, TiW and TiAlN.