A three-dimensional memory device comprising: an alternating stack of insulating layers and electrically conductive layers located over a substrate (9, 10); a drain select level isolation dielectric structure; and memory stack structures extending through the alternating stack (32, 46), wherein each of the memory stack structures comprises a memory film and a vertical semiconductor channel contacting an inner sidewall of the memory film, wherein: two or more uppermost layers among the electrically conductive layers include first strip portions and second strip portions that are laterally spaced from one another by the drain select level isolation dielectric structure; and the device is characterized in that: the drain select level isolation dielectric structure includes a pair of alternating sequences of non-concave sidewall portions (12P1, 12P2) and concave sidewall portions; and the device further comprises: a first vertical conductive connector contacting each of the first strip portions of the two or more uppermost layers among the electrically conductive layers; and a second vertical conductive connector contacting each of the second strip portions of the two or more uppermost layers among the electrically conductive layers; wherein: the first vertical conductive connector and the first strip portions of the two or more uppermost layers among the electrically conductive layers constitute a first continuous conductive structure; and the second vertical conductive connector and the second strip portions of the two or more uppermost layers among the electrically conductive layers constitute a second continuous conductive structure. an alternating stack of insulating layers and electrically conductive layers located over a substrate (9, 10); a drain select level isolation dielectric structure; and memory stack structures extending through the alternating stack (32, 46), wherein each of the memory stack structures comprises a memory film and a vertical semiconductor channel contacting an inner sidewall of the memory film, wherein: two or more uppermost layers among the electrically conductive layers include first strip portions and second strip portions that are laterally spaced from one another by the drain select level isolation dielectric structure; and the device is characterized in that: the drain select level isolation dielectric structure includes a pair of alternating sequences of non-concave sidewall portions (12P1, 12P2) and concave sidewall portions; and the device further comprises: a first vertical conductive connector contacting each of the first strip portions of the two or more uppermost layers among the electrically conductive layers; and a second vertical conductive connector contacting each of the second strip portions of the two or more uppermost layers among the electrically conductive layers; wherein: the first vertical conductive connector and the first strip portions of the two or more uppermost layers among the electrically conductive layers constitute a first continuous conductive structure; and the second vertical conductive connector and the second strip portions of the two or more uppermost layers among the electrically conductive layers constitute a second continuous conductive structure. two or more uppermost layers among the electrically conductive layers include first strip portions and second strip portions that are laterally spaced from one another by the drain select level isolation dielectric structure; and the device is characterized in that: the drain select level isolation dielectric structure includes a pair of alternating sequences of non-concave sidewall portions (12P1, 12P2) and concave sidewall portions; and the device further comprises: a first vertical conductive connector contacting each of the first strip portions of the two or more uppermost layers among the electrically conductive layers; and the first vertical conductive connector and the first strip portions of the two or more uppermost layers among the electrically conductive layers constitute a first continuous conductive structure; and the second vertical conductive connector and the second strip portions of the two or more uppermost layers among the electrically conductive layers constitute a second continuous conductive structure.