Self-aligned transparent metal oxide TFT on flexible substrate

A method of fabricating self-aligned metal oxide TFTs on transparent flexible substrates comprising the steps of:

• providing a transparent flexible substrate having a front surface and a rear surface;
• positioning a structure including at least an opaque first metal TFT electrode and a layer of transparent material on the front surface of the substrate;
• positioning a layer of photoresist in overlying relationship to the structure;
• positioning a first photo mask over the rear surface of the substrate in non-critical alignment;
• exposing portions of the layer of photoresist through the first photo mask and using the opaque first metal TFT electrode as a self-alignment mask in cooperation with the first photo mask;
• positioning a second photo mask over the front surface of the substrate in non-critical alignment;
• exposing portions of the layer of photoresist using the second photo mask;
• the first photo mask being constructed to define pattern in a complementary area of the opaque first metal TFT electrode and the layer of transparent material and the second photo mask being constructed to define pattern in an overlap area of the opaque first metal TFT electrode and the layer of transparent material;
• and
• developing the layer of photoresist and forming a layer of second metal using the developed layer of photoresist.