Three-dimensional memory device containing self-aligned lateral contact elements and methods for forming the same

A three-dimensional memory device, comprising:

• an alternating stack of insulating layers and electrically conductive layers having stepped surfaces;
• memory stack structures extending through the alternating stack, wherein each of the memory stack structures comprises a vertical semiconductor channel and a vertical stack of memory elements;
• a retro-stepped dielectric material portion overlying the stepped surfaces;
• and
• pillar-shaped contact-opening assemblies located within a respective pillar-shaped volume vertically extending through the retro-stepped dielectric material portion and a region of the alternating stack that underlies the retro-stepped dielectric material portion,
• wherein:
• a first one of the pillar-shaped contact-opening assemblies comprises a first conductive plug that laterally contacts a cylindrical sidewall of one of the electrically conductive layers and a conductive via structure that contacts a top surface of the first conductive plug and vertically extends at least to a horizontal plane including a top surface of the retro-stepped dielectric material portion;
• the first one of the pillar-shaped contact-opening assemblies comprises a vertically alternating stack of encapsulated cavities and additional conductive plugs;
• each of the encapsulated cavities is located at a level of a respective one of the insulating layers;
• and
• each of the additional conductive plugs is located at a level of a respective one of the electrically conductive layers.

A three-dimensional memory device, comprising:

• an alternating stack of insulating layers and electrically conductive layers having stepped surfaces;
• memory stack structures extending through the alternating stack, wherein each of the memory stack structures comprises a vertical semiconductor channel and a vertical stack of memory elements;
• a retro-stepped dielectric material portion overlying the stepped surfaces;
• and
• pillar-shaped contact-opening assemblies located within a respective pillar-shaped volume vertically extending through the retro-stepped dielectric material portion and a region of the alternating stack that underlies the retro-stepped dielectric material portion,
• wherein:
• a first one of the pillar-shaped contact-opening assemblies comprises a first conductive plug that laterally contacts a cylindrical sidewall of one of the electrically conductive layers and a conductive via structure that contacts a top surface of the first conductive plug and vertically extends at least to a horizontal plane including a top surface of the retro-stepped dielectric material portion;
• each of the pillar-shaped contact-opening assemblies comprises at least one pair of a conductive plug and an encapsulated cavity arranged along a vertical direction;
• and
• a total number of the at least one pair is different among the pillar-shaped contact-opening assemblies.

A three-dimensional memory device, comprising:

• an alternating stack of insulating layers and electrically conductive layers having stepped surfaces;
• memory stack structures extending through the alternating stack, wherein each of the memory stack structures comprises a vertical semiconductor channel and a vertical stack of memory elements;
• a retro-stepped dielectric material portion overlying the stepped surfaces;
• and
• pillar-shaped contact-opening assemblies located within a respective pillar-shaped volume vertically extending through the retro-stepped dielectric material portion and a region of the alternating stack that underlies the retro-stepped dielectric material portion,
• wherein a first one of the pillar-shaped contact-opening assemblies comprises a first conductive plug that laterally contacts a cylindrical sidewall of one of the electrically conductive layers and a conductive via structure that contacts a top surface of the first conductive plug and vertically extends at least to a horizontal plane including a top surface of the retro-stepped dielectric material portion;
• and
• wherein each of the pillar-shaped contact-opening assemblies vertically extends through a bottommost one of the electrically conductive layers, and comprises a respective conductive plug that contacts a respective cylindrical sidewall of the bottommost one of the electrically conductive layers.