METHOD OF PROCESSING SEMICONDUCTOR THIN FILM AND MANUFACTURE OF SEMICONDUCTOR DEVICE HAVING CAPACITIVE ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a method for processing a semiconductor thin film, which can have surface irregularities with good controllability and reproducibility, and also to provide a method for fabricating a semiconductor device having a capacitive element with a large retained capacitance value with good controllability and reproductivity. SOLUTION: A light-shielding film 1 is formed on a cleaned insulating substrate in the form of a predetermined pattern, and then a base coat film 2 of SiO2 is deposited thereon by a CVD process. Subsequently, a semiconductor thin film 3 of amorphous Si (a.Si) is deposited thereon, subjected to a patterning process and then to a first laser beam irradiation to crystallize a.Si into polycrystalline p.Si. Further, only a capacitance formation region of the thin film 3 of p.Si is subjected to a second laser beam irradiation from a rear side of the insulating substrate to form surface irregularities thereon. Next, a gate insulating film 5 of SiO2 is deposited and also acts as an insulating film of a capacitive element. An Al-Si layer is deposited and subjected to a patterning process to form a gate electrode 6, a capacitive element electrode 7, an interlayer insulating film 8 and source and drain electrodes 9 and 10.