Manufacturing method for SOI-type thin film transistor

Claim 1

A method of manufacturing a double gate structure SOI-type thin film transistor, comprising the steps of: (a) forming a first gate electrode on one surface of a transparent substrate; (b) forming a first gate insulating layer covering the first gate electrode; (c) forming a semiconductor layer covering the first gate insulating layer on the substrate; (d) forming a second gate insulating layer covering the semiconductor layer; (e) depositing a positive photoresist on the second gate insulating layer; (f) irradiating light selectively onto the photoresist from another surface of the transparent substrate through the substrate and the first gate electrode using the first gate electrode as a photomask, and subjecting the photoresist to a patterning process; (g) injecting an ion into the semiconductor layer using the patterned photoresist as a mask, to form a source or a drain region in the semiconductor layer; (h) removing the patterned photoresist; (i) forming a conductive layer on the second gate insulating layer; (j) depositing a positive photoresist on the conductive layer; (k) irradiating light selectively onto the photoresist from the other surface of the transparent substrate through the substrate and the first electrode using the first electrode as a photomask; and (l) patterning the photoresist, and etching the conductive layer using the patterned photoresist as the mask to form a second electrode.

Claim 2

A method of manufacturing a double gate structure SOI-type thin film transistor, comprising the steps of: (a) forming a first gate electrode on one surface of a transparent substrate; (b) forming a first gate insulating layer covering the first gate electrode; (c) forming a semiconductor layer covering the first gate insulating layer on the substrate; (d) forming a second gate insulating layer covering the semiconductor layer; (e) depositing a positive photoresist on the second gate insulating layer; (f) irradiating light selectively onto the photoresist from another surface of the transparent substrate through the substrate and the first gate electrode using the first gate electrode as a photomask, and subjecting the photoresist to a patterning process; (g) injecting an ion into the semiconductor layer using the patterned photoresist as a mask, to form a source or a drain region in the semiconductor layer; (h) removing the patterned photoresist; (i) forming a conductive layer on the second gate insulating layer; (j) depositing a positive photoresist on the conductive layer; (k) irradiating light selectively onto the photoresist from the other surface of the transparent substrate through the substrate and the first electrode using the first electrode as a photomask; and (l) patterning the photoresist, and etching the conductive layer using the patterned photoresist as the mask to form a second electrode.