Meanwhile, in the second thin film transistor of the present disclosure, the second active layer under the contact hole may have a symmetrical structure, but is not limited thereto.

For example, although FIG. 9 illustrates that the first active layer 121 under the contact hole CH has a structure having top and bottom asymmetry and left and right asymmetry, as an example, the present disclosure is not limited thereto, and the first active layer 121 under the contact hole CH has a structure having top and bottom asymmetry or left and right asymmetry. For example, the contact hole CH connecting the first source electrode 122 or the first drain electrode 123 to respective regions of the first active layer 121 may expose at least a portion of the first active layer 121. As shown in FIG. 9, a top surface of the exposed portion of the first active layer 121 may be shaped asymmetrically with respect to a reference line extending in a first direction, such that a portion of the first active layer 121 on one side of the reference line is shaped differently from another portion of the first active layer 121 on the other side of the reference line. For example, the first direction may be a vertical direction in FIG. 9 extending from a top edge of the contact hole CH to a bottom edge of the contact hole CH, or a horizontal direction extending from a left edge of the contact hole CH to a right edge of the contact hole CH. Moreover, the top surface of the exposed portion may be shaped asymmetrically with respect to a reference line extending in a first direction (e.g., vertical direction) and a second direction intersecting the first direction (e.g., horizontal direction).