A display device comprising: an auxiliary electrode on a lower substrate in a non-light emitting area of the display device; a lower passivation layer on the auxiliary electrode, the lower passivation layer comprising an insulating material and including a first penetrating hole exposing the auxiliary electrode; and an over-coat layer on the lower passivation layer, the over-coat layer comprising an organic insulating material and including a second penetrating hole, a light-emitting structure on the passivation layer in a light emitting area of the display device, the light-emitting structure including a lower electrode, an upper electrode, and a light-emitting layer between the lower electrode and the upper electrode, wherein a portion of the upper electrode is located in the first penetrating hole and a portion of the upper electrode is located in the second penetrating hole and the upper electrode is electrically connected to the auxiliary electrode through the first penetrating hole and the second penetrating hole, wherein, in a plan view of the display device in which the first and second penetrating holes are viewed from a direction parallel to a normal of a planar surface of the auxiliary electrode, a side surface of the second penetrating hole intersects, in the plan view of the display device, a side surface of the first penetrating hole such that the side surface of the second penetrating hole includes a first side region disposed inside the first penetrating hole and a second side region disposed outside the first penetrating hole to overlap with the lower passivation layer, wherein the first side region has a negative taper and the second side region has a positive taper, wherein an under-cut region formed by the lower passivation layer and the over-coat layer is disposed on the auxiliary electrode, wherein the auxiliary electrode is electrically connected to the upper electrode by the under-cut region. an auxiliary electrode on a lower substrate in a non-light emitting area of the display device; a lower passivation layer on the auxiliary electrode, the lower passivation layer comprising an insulating material and including a first penetrating hole exposing the auxiliary electrode; and an over-coat layer on the lower passivation layer, the over-coat layer comprising an organic insulating material and including a second penetrating hole, a light-emitting structure on the passivation layer in a light emitting area of the display device, the light-emitting structure including a lower electrode, an upper electrode, and a light-emitting layer between the lower electrode and the upper electrode, wherein a portion of the upper electrode is located in the first penetrating hole and a portion of the upper electrode is located in the second penetrating hole and the upper electrode is electrically connected to the auxiliary electrode through the first penetrating hole and the second penetrating hole, wherein, in a plan view of the display device in which the first and second penetrating holes are viewed from a direction parallel to a normal of a planar surface of the auxiliary electrode, a side surface of the second penetrating hole intersects, in the plan view of the display device, a side surface of the first penetrating hole such that the side surface of the second penetrating hole includes a first side region disposed inside the first penetrating hole and a second side region disposed outside the first penetrating hole to overlap with the lower passivation layer, wherein the first side region has a negative taper and the second side region has a positive taper, wherein an under-cut region formed by the lower passivation layer and the over-coat layer is disposed on the auxiliary electrode, wherein the auxiliary electrode is electrically connected to the upper electrode by the under-cut region.