Memory die with source side of three-dimensional memory array bonded to logic die and methods of making the same

A memory die includes an alternating stack of insulating layers and electrically conductive layers located between a drain-side dielectric layer and a source-side dielectric layer. Memory openings vertically extend through the alternating stack. Each of the memory openings has a greater lateral dimension an interface with the source-side dielectric layer than at an interface with the drain-side dielectric layer. Memory opening fill structures are located in the memory openings. Each of the memory opening fill structures includes a vertical semiconductor channel, a vertical stack of memory elements, and a drain region. A logic die may be bonded to a source-side dielectric layer side of the memory die.