Mask plate and manufacturing method thereof

The invention provides a mask plate and a manufacturing method thereof. The mask plate is characterized in that a halftone mask technology (a semi light-permeable sub area in a partially light-permeable area) is utilized to ensure the uniformity of the thickness of photoresist, or in a junction of the partially light-permeable area and a light-proof area, or a junction of a partially light-permeable area or a completely light-permeable area, a gray tone mask technology (slit) is utilized to ensure the light intensity at the junction to be as consistent as possible with the light intensity in the semi light-permeable sub area, so that the intensity of light permeating the partially light-permeable area is uniform, and an edge angle of a photoresist retaining area is increased. According to the technical scheme provided by the invention, the process in a TFT (thin film transistor) channel forming process is precisely controlled, and the reliability of the TFT channel size is ensured, so that the electric properties of a TFT array substrate can be effectively improved.