Abstract: First memory openings are formed through a first alternating stack of first insulating layers and first spacer material layers. Each first memory opening is filled with a first memory film, a sacrificial dielectric liner, and a first-tier opening fill material portion. Second memory openings are formed through a second alternating stack of second insulating layers and second spacer material layers. A second memory film is formed in each second memory opening. The first-tier opening fill material portions are removed selective to the sacrificial dielectric liners. The sacrificial dielectric liners are removed selective to the second memory films and the first memory films. A vertical semiconductor channel can be formed on each vertical stack of a first memory film and a second memory film.

Abstract: An alternating stack of insulating layers and sacrificial material layers is formed with stepped surfaces. Sacrificial metal plates are formed on the top surfaces of the sacrificial material layers, and a retro-stepped dielectric material portion is formed over the sacrificial metal plates. Contact via cavities are formed through the retro-stepped dielectric material portion employing the sacrificial metal plates as etch stop structures. The sacrificial metal plates are replaced with portions of insulating spacer layers. Sacrificial via fill structures within remaining volumes of the contact via cavities. The sacrificial material layers are replaced with electrically conductive layers. The sacrificial via fill structures are replaced with portions of staircase-region contact via structures that contact the electrically conductive layers.

Abstract: An alternating stack of insulating layers and sacrificial material layers is formed with stepped surfaces. Sacrificial metal plates are formed on the top surfaces of the sacrificial material layers, and a retro-stepped dielectric material portion is formed over the sacrificial metal plates. Contact via cavities are formed through the retro-stepped dielectric material portion employing the sacrificial metal plates as etch stop structures. The sacrificial metal plates are replaced with portions of insulating spacer layers. Sacrificial via fill structures within remaining volumes of the contact via cavities. The sacrificial material layers are replaced with electrically conductive layers. The sacrificial via fill structures are replaced with portions of staircase-region contact via structures that contact the electrically conductive layers.

Abstract: In a connection structure of a tubular connection member and a joint member according to an embodiment, a joint member (20) with a cap nut (30) mounted thereon is connected to a tubular connection member (12) with a spiral ridge (14) and a flange (16). The cap nut (30) has a spiral groove formed in the inner peripheral surface and includes a detent member (35) having a movable portion (36) and an extending portion (37). A spigot portion of the joint member (20) is inserted into the tubular connection member (12), and the cap nut (30) is screwed in. Then, the extending portion (37) of the detent member (35) is locked by a locking protrusion (162) provided on the flange (16) of the tubular connection member (12).

Abstract: In a connection structure of a tubular connection member and a joint member according to an embodiment, a joint member (20) with a cap nut (30) mounted thereon is connected to a tubular connection member (12) with a spiral ridge (14) and a flange (16). The cap nut (30) has a spiral groove formed in the inner peripheral surface and includes a detent member (35) having a movable portion (36) and an extending portion (37). A spigot portion of the joint member (20) is inserted into the tubular connection member (12), and the cap nut (30) is screwed in. Then, the extending portion (37) of the detent member (35) is locked by a locking protrusion (162) provided on the flange (16) of the tubular connection member (12).