Three-dimensional memory devices with stacked device chips using interposers

A three-dimensional (3D) memory device, comprising:

• a first device chip, comprising:
• a first alternating conductor/dielectric stack and a first memory string extending vertically through the first alternating conductor/dielectric stack;
• and
• a first chip contact disposed on a surface of the first device chip and electrically connected to the first memory string;
• a second device chip, comprising:
• a second alternating conductor/dielectric stack and a second memory string extending vertically through the second alternating conductor/dielectric stack;
• and
• a second chip contact disposed on a surface of the second device chip and electrically connected to the second memory string;
• and
• an interposer disposed vertically between the first device chip and the second device chip, the interposer comprising:
• an interposer substrate;
• a first interposer contact disposed on a first surface of the interposer;
• and
• a second interposer contact disposed on a second surface opposite to the first surface of the interposer and electrically connected to the first interposer contact through the interposer substrate,
• wherein the first interposer contact is attached to the first chip contact, and the second interposer contact is attached to the second chip contact.

A method for forming a three-dimensional (3D) memory device, comprising:

• forming an alternating conductor/dielectric stack at a first side of a chip substrate;
• forming a memory string extending vertically through the alternating conductor/dielectric stack;
• forming a chip contact at a second side opposite to the first side of the chip substrate, the chip contact electrically connected to the memory string;
• forming a first interposer contact at a first side of an interposer substrate;
• forming a second interposer contact at a second side opposite to the first side of the interposer substrate, the second interposer contact electrically connected to the first interposer contact through the interposer substrate;
• and
• attaching the first interposer contact to the chip contact.

A method for forming a three-dimensional (3D) memory device, comprising:

• forming an alternating conductor/dielectric stack at a first side of a chip substrate;
• forming a memory string extending vertically through the alternating conductor/dielectric stack;
• forming a chip contact at the first side of the chip substrate, the chip contact electrically connected to the memory string;
• forming a first interposer contact at a first side of an interposer substrate;
• forming a second interposer contact at a second side opposite to the first side of the interposer substrate, the second interposer contact electrically connected to the first interposer contact through the interposer substrate;
• and
• attaching the first interposer contact to the chip contact.