Thin film transistor display panel and manufacturing method thereof

PURPOSE: A thin film transistor array panel and a production method thereof are provided to etch semiconductor substances and metal substances using the first mask to reduce the generation of a scue and an undercut by forming a channel portion using the second mask. CONSTITUTION: A semiconductor layer(151) is formed on a gate insulating layer(140). The semiconductor layer contains a channel portion which corresponds to a part in which a source electrode(173) and a drain electrode(175) are separated. The semiconductor layer is overlapped with the semiconductor layer to have 'the same boundary with a data line(171), the source electrode, and the drain electrode' except for the channel portion.