Process of manufacturing thin film transistor

A process of producing a thin film transistor, comprising:

• sequentially forming a first metal layer and a first photoresist on a substrate;
• patterning the first photoresist by exposure and development processes using a first photomask, and forming a gate line on the substrate by etching, and removing the first photoresist after exposure;
• sequentially forming an insulator layer, a semiconductor layer, an ohmic contact layer, a second metal layer and a second photoresist layer on a gate line;
• patterning the second photoresist by exposure and development processes using a second photoresist, and forming a source and a drain on the ohmic contact layer alter etching to form a semiconductor channel between the source and the drain, and removing the second photoresist after exposure;
• forming a third photoresist layer on the substrate, wherein the substrate includes the source, the drain, the semiconductor channel and the semiconductor layer;
• patterning the third photoresist layer by exposure and development processes using a third photomask, and forming an island-shaped transistor region after etching and removing the third photoresist;
• sequentially forming a protection layer and a fourth photoresist layer on the substrate with the island-shaped transistor region therein;
• patterning the fourth photoresist layer by exposure and development processes using a fourth photomask, and defining a contact hole in the protection layer by etching, and removing the fourth photoresist layer;
• sequentially forming a pixel electrode and a fifth photoresist layer on the protection layer;
• and
• patterning a fifth photoresist by exposure and development processes using a fifth photomask, and forming a pixel electrode by etching that connects to the drain via the contact hole, and removing the fifth photoresist layer.