Array substrate, display panel, and manufacturing method of the array substrate

A method for manufacturing an array substrate, comprising:

• forming an insulation layer;
• and
• patterning the insulation layer to form one or more stepped holes each penetrating through the insulation layer in a direction perpendicular to the insulation layer,
• wherein the patterning the insulation layer to form the one or more stepped holes each penetrating through the insulation layer in the direction perpendicular to the insulation layer comprises:
• forming a first photoresist layer on the insulation layer, and exposing and developing the first photoresist layer with an exposure mask plate in a first exposure condition, so as to remove a part of the first photoresist layer, thereby to expose a first to-be-etched region of the insulation layer;
• dry-etching the first to-be-etched region of the insulation layer in a first process condition to form a first hole, and removing the remaining first photoresist layer;
• forming a second photoresist layer on the insulation layer, and exposing and developing the second photoresist layer with the exposure mask plate in a second exposure condition, so as to remove a part of the second photoresist layer, thereby to expose a second to-be-etched region of the insulation layer, the second photoresist layer being made of a material different from the first photoresist layer and/or the second exposure condition being different from the first exposure condition so that the second to-be-etched region is located within the first to-be-etched region and an area of the second to-be-etched region is smaller than an area of the first to-be-etched region;
• and
• dry-etching the second to-be-etched region of the insulation layer in a second process condition to form a second hole, and removing the remaining second photoresist layer,
• wherein each stepped hole comprises the first hole and the second hole under the first hole, a radius of the first hole at a bottom is a first radius, a radius of the second hole at a top is a second radius which is substantially smaller than the first radius, and a difference between the first radius and the second radius is 0.2 μm to 0.6 μm.