Manufacturing method of tft array substrate, tft array substrate and display device

A manufacturing method of a TFT array substrate, comprising steps of:

• S1. forming a thin film transistor on a base substrate;
• S2. forming a passivation layer thin film on the base substrate after the step S1;
• S3. forming a passivation layer via hole and a light-shielding pattern on the base substrate after the step S2;
• and
• S4. forming a color filter layer and a pixel electrode on the base substrate after the step S3,
• wherein the pixel electrode is electrically connected to a drain electrode of the thin film transistor through the passivation layer via hole, and the color filter layer is in correspondence with a position of the pixel electrode,
• wherein the forming the passivation layer via hole comprises:
• forming a layer of photoresist on the base substrate after the step S2;
• exposing and developing the photoresist by using a mask plate to form a photoresist-completely-removed region and a photoresist-completely-reserved region, wherein the photoresist-completely-removed region corresponds to a region where the passivation layer via hole is to be formed and the photoresist-completely-reserved region corresponds to remaining regions;
• and
• removing the passivation layer thin film of the photoresist-completely-removed region, to form the passivation layer via hole, and
• wherein the forming the light-shielding pattern comprises:
• thinning the photoresist of the photoresist-completely-reserved region through an ashing process until the thin film transistor is exposed, wherein other regions than the thin film transistor is still covered by a remaining portion of the photoresist which has a reduced thickness;
• forming a light-shielding conductive metal layer thin film to cover the thin film transistor and other regions than the thin film transistor;
• stripping off the remaining portion of the photoresist to form the light-shielding pattern above the thin film transistor, wherein the light-shielding conductive metal layer thin film still remains in the passivation layer via hole.