Semiconductor devices and fabrication methods thereof

A semiconductor device, comprising:

• a first stack of conductive layers and insulating layers alternating with each other along a first direction, wherein the first stack comprises a first deck of conductive layers and insulating layers and a second deck of conductive layers and insulating layers;
• a second stack of dielectric layers and insulating layers alternating with each other along the first direction, wherein the second stack comprises a first deck of dielectric layers and insulating layers and a second deck of dielectric layers and insulating layers;
• a first connecting layer connecting a first conductive layer of the first deck of the first stack with a first dielectric layer of the first deck of the second stack along a second direction perpendicular to the first direction;
• a second connecting layer connecting a second conductive layer of the second deck of the first stack with a second dielectric layer of the second deck of the second stack along the second direction;
• a first contact structure extending through the first deck of the second stack along the first direction, wherein the first contact structure extends through and is connected with the first connecting layer;
• and
• a second contact structure extending through the first deck and the second deck of the second stack along the first direction, wherein the second contact structure extends through the first connecting layer and the second connecting layer and is connected with the second connecting layer, and the second contact structure is isolated from the first connecting layer by a dielectric spacer.

A method, comprising:

• forming a first stack of conductive layers and insulating layers alternating with each other along a first direction and a second stack of dielectric layers and insulating layers alternating with each other along the first direction, wherein the first stack comprises a first deck of conductive layers and insulating layers and a second deck of conductive layers and insulating layers, and the second stack comprises a first deck of dielectric layers and insulating layers and a second deck of dielectric layers and insulating layers;
• forming a first connecting layer and a second connecting layer, wherein the first connecting layer connects a first conductive layer of the first deck of the first stack with a first dielectric layer of the first deck of the second stack along a second direction perpendicular to the first direction, and the second connecting layer connects a second conductive layer of the second deck of the first stack with a second dielectric layer of the second deck of the second stack along the second direction;
• and
• forming an isolating structure extending through the first deck of the second stack along the first direction, wherein the isolating structure extends through the first connecting layer and the second connecting layer along the first direction, and the isolating structure comprises a dielectric layer.