| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a TFT including at least one LDD region in self-alignment manner without forming a sidewall spacer and increasing the number of steps, and also provide a manufacturing method for forming various TFTs on the same substrate without increasing the number of steps, such as a TFT having the LDD region on one side of a channel formation region, and a TFT having the LDD region on both sides of the channel formation region. <P>SOLUTION: By applying a photo mask or reticle provided with a diffraction grating pattern or an auxiliary pattern composed of a semi-permeable membrane and having an optical strength reduction function to a photolithography process for gate electrode formation, asymmetric resist patterns having a side part on one side thereof a region having a large thickness and a region having a smaller thickness than the former region are formed, and a gate electrode having a step is formed, and impurity element is implanted into the semiconductor layer by allowing the impurity element to pass through the region having the smaller thickness of the gate electrode, thereby forming an LDD region in self-alignment manner. <P>COPYRIGHT: (C)2012,JPO&INPIT |
