A memory structure is described, which includes a substrate, a word line structure, a bit line contact, and a bit line. The substrate has a trench. The word line structure is disposed in the trench of the substrate. The word line structure includes a word line, a gate dielectric layer, and a capping layer. The word line is disposed in the trench. The gate dielectric layer is disposed between the word line and the substrate. The capping layer covers the word line. The capping layer includes a first material film, and a dielectric constant of the first material layer is smaller than a dielectric constant of silicon nitride. The bit line contact is disposed on a portion of the trench and a portion of the capping layer. The bit line is disposed over the bit line contact and electrically connected to the bit line contact.

Some embodiments include a method of forming an integrated assembly. An arrangement is formed to include a conductive pillar extending through an insulative mass. An upper surface of the conductive pillar is recessed to form a cavity. An insulative collar is formed within the cavity to line an outer lateral periphery of the cavity. A recessed surface of the conductive pillar is exposed at a bottom of the lined cavity. A conductive expanse is formed over the insulative mass. A portion of the conductive expanse extends into the cavity and is configured as an interconnect. The conductive expanse is patterned into multiple conductive structures. One of the conductive structures includes the interconnect.

A method includes etching a substrate to form an opening, depositing a first dielectric liner extending into the opening, and depositing a second dielectric liner over the first dielectric liner. The second dielectric liner extends into the opening. A conductive material is filled into the opening. The method further includes performing a first planarization process to planarize the conductive material so that a portion of the conductive material in the opening forms a through-via, performing a backside grinding process on the substrate until the through-via is revealed from a backside of the substrate, and forming a conductive feature on the backside of the substrate. The conductive feature is electrically connected to the through-via.

A method includes etching a substrate to form an opening, depositing a first dielectric liner extending into the opening, and depositing a second dielectric liner over the first dielectric liner. The second dielectric liner extends into the opening. A conductive material is filled into the opening. The method further includes performing a first planarization process to planarize the conductive material so that a portion of the conductive material in the opening forms a through-via, performing a backside grinding process on the substrate until the through-via is revealed from a backside of the substrate, and forming a conductive feature on the backside of the substrate. The conductive feature is electrically connected to the through-via.