Method for forming a self-aligned bit line for PCRAM and self-aligned etch back process

A method of forming a device comprising:

• forming a pedestal of a sacrificial material on a portion of a lower electrode;
• forming at least one dielectric material adjacent to the sacrificial material, the at least one dielectric material has an upper surface substantially coplanar with an upper surface of the pedestal of the sacrificial material;
• removing the pedestal of the sacrificial material selective to the at least one dielectric material and the lower electrode to provide an opening to an exposed surface of the lower electrode;
• depositing a phase change material on the exposed surface of the lower electrode, wherein the depositing of the phase change material on the exposed surface of the lower electrode comprises a Te-containing material deposited by physical vapor deposition, wherein the phase change material is also formed on the upper surface of the at least one dielectric material;
• and
• filling the opening with a conductive fill material, wherein the filling of the opening with the conductive fill material comprises:
• depositing a spin-on-glass or photoresist material filling the opening,
• planarizing to remove the phase change material that is present on the upper surface of the at least one dielectric material,
• removing the sacrificial filler material that is filling the opening,
• depositing a barrier layer within the opening,
• depositing the conductive fill material within at least the opening, and
• planarizing the conductive fill material, wherein the upper surface of the conductive fill material is substantially coplanar with the upper surface of the at least one dielectric material.

A method of forming a device comprising:

• providing an opening through a material stack to a lower electrode;
• depositing a phase change material on an exposed surface of the lower electrode;
• forming an upper electrode on the phase change material that is present within the opening, wherein electrically conductive material that provides the upper electrode is also formed overlying an upper surface of the material stack;
• filling the opening with an etch stop material;
• etching the electrically conductive material that is present overlying the upper surface of the material stack, wherein the upper electrode that is present within the opening is protected by the etch stop material;
• removing the etch stop material with an etch that is selective to the upper electrode and the material stack;
• and
• forming a via in electrical communication with the upper electrode.