Array substrate and manufacturing method thereof

A method of manufacturing an array substrate, comprising steps of:

• forming at least a first conductive pattern on a base substrate;
• forming a first insulating layer on the base substrate with the first conductive pattern formed thereon;
• forming at least a second conductive pattern on the first insulating layer;
• forming a second insulating layer on the base substrate with the second conductive pattern formed thereon;
• patterning the second insulating layer and the first insulating layer with a double-tone mask, forming at least a half lap joint via hole in the second insulating layer, and forming at least a full lap joint via hole in both the first insulating layer and the second insulating layer, wherein the second conductive pattern corresponds to a part of the half lap joint via hole, and the first conductive pattern corresponds to the whole of the full lap joint via hole;
• and
• forming at least a third conductive pattern and a fourth conductive pattern on the base substrate with the half lap joint via hole and the full lap joint via hole formed thereon, wherein the third conductivity pattern is formed on the surface of the second conductivity pattern and the first insulating layer through the half lap joint via hole, and the fourth conductive pattern is formed on the surface of the first conductive pattern through the full lap joint via hole;
• wherein patterning the second insulating layer and the first insulating layer with a double-tone mask comprises:
• applying a layer of photoresist on the second insulating layer;
• exposing and developing the photoresist with a double-tone mask, so as to form a pattern of the photoresist layer, which comprises a fully retained region, a partially retained region, and a completely removed region, wherein the completely removed region corresponds to the full lap joint via hole and corresponds to a part of the half lap joint via hole that is disposed on the drain electrode, the partially retained region corresponds to the remaining part of the half lap joint via hole, and the fully retained region corresponds to the region other than the completely removed region and the partially retained region, wherein the half lap joint via hole corresponds to a combination of the partially retained region and a part of the completely removed region;
• performing a first dry etching to etch away at least the part of the second insulating layer that corresponds to the completely removed region and expose the drain electrode corresponding to the part of the half lap joint via hole;
• aching the photoresist in accordance with the thickness of the photoresist in the partially retained region and expose the second insulating layer corresponding to the remaining part of the half lap joint via hole;
• and
• performing a second dry etching to etch away the part of the second insulating layer to expose the first insulating layer that corresponds to the remaining part of the half lap joint via hole and to etch away the part of the first insulating layer that corresponds to the completely removed region, so as to form the half lap joint via hole and the full lap joint via hole.