Manufacturing method of semiconductor devices

Abstract

To provide a manufacturing method of thin film transistors (TFT) using poly-silicone and having an LDD structure. In particular, the LDD sections of the TFTs are formed in an improved method so as to achieve a high throughput and stable performance of the TFTs. To be specific, the LD region is doped at a low concentration in the ion implantation method which includes mass spectrometry because high controllability over a dose is required. On the other hand, the source and drain regions are doped at a higher concentration than the LD region in the ion showering method which does not include mass spectrometry. Using the ion showering method, poly-crystal silicon can be doped such that less doping damage is caused thereto. This makes it possible to apply a lower temperature for annealing, such as RTA, to activate doped impurities so as to prevent the substrate from being curved. Further, combination of the ion implantation method and the showering method achieves a high throughput production of TFTs having stable performance.