Method for forming memory device

A method for forming a memory device, comprising:

• forming a stack comprising a first sacrificial layer, a first supporting layer, a second sacrificial layer, and a second supporting layer over a substrate;
• forming a first trench, a second trench, and a third trench in the stack, wherein a distance between the first trench and the second trench is less than a distance between the first trench and the third trench;
• forming bottom electrodes in the first, second, and third trenches, respectively;
• forming a patterned mask over the stack, wherein the patterned mask has an opening exposing the stack;
• performing an etch process to the stack through the opening of the patterned mask to form a recess in the stack, wherein after the etch process is complete, a first portion of the second supporting layer laterally between the first trench and the second trench remains, while a second portion of the second supporting layer
• laterally between the first trench and the third trench is removed;
• removing the first sacrificial layer and the second sacrificial layer from the stack through the recess;
• forming capacitor dielectric layers over the bottom electrodes, respectively;
• and
• forming top electrodes over the capacitor dielectric layers, respectively.