Thin film transistor substrate, display apparatus comprising the same, method of manufacturing thin film transistor substrate, and method of manufacturing display apparatus

A method of manufacturing a thin film transistor (TFT) substrate, the method comprising:

• forming a first gate electrode on a substrate such that the first gate electrode including a first branch electrode and a second branch electrode that are spaced apart from one another;
• forming a first gate insulating layer that covers the first gate electrode;
• forming an amorphous silicon layer on the first gate insulating layer;
• crystallizing the amorphous silicon layer to form a polysilicon layer;
• forming a second gate insulating layer that covers the polysilicon layer;
• and
• forming a second gate electrode on the second gate insulating layer such that the second gate electrode overlies the first and second branch electrodes,
• wherein:
• the polysilicon layer includes a first portion,
• the polysilicon layer includes second portions that overlie the first and second branch electrodes, the first portion being between the second portions, and
• a grain size of the first portion of the polysilicon layer is larger than a grain size of the second portions of the polysilicon layer.

A thin film transistor (TFT) substrate, comprising:

• a substrate;
• a first gate electrode on the substrate, the first gate electrode including a first branch electrode and a second branch electrode that are spaced apart from one another;
• a polysilicon layer on the first gate electrode and insulated from the first gate electrode;
• and
• a second gate electrode on the polysilicon layer, the second gate electrode being insulated from the polysilicon layer and overlying the first and second branch electrodes,
• a first gate insulating layer between the first gate electrode and the polysilicon layer;
• and
• a second gate insulating layer between the second gate electrode and the polysilicon layer,
• wherein each of the first and second gate insulating layers has a through hole such that the first and second gate electrodes are connected.