MANUFACTURE OF HEMISPHERICAL CRYSTAL GRAIN

摘要

PROBLEM TO BE SOLVED: To prevent the formation failure of a hemispherical crystal grain due to a natural oxide film by cleaning a polysilicon film that has been subjected to etching patterning so that it is in-situ in a reaction chamber for growing hemispherical crystal grain and growing a hemispherical crystal flow on the silicon surface. SOLUTION: The size of a hemispherical crystal grain 604 formed on the upper surface of a storage node 603 is relatively larger than that of a hemispherical crystal particle 605 formed on a side wall, since the upper surface of a structure is etched larger than a side-wall surface caused by the anisotropic characteristics of an etching process at an in-situ plasma etching cleaning stage. As a result, a remaining natural oxide film becomes smaller on the upper surface of the storage node 603 than on the side-wall surface, so that the size of the hemispherical crystal grain formed on the upper surface becomes larger than that on the side wall. As a result, by performing a pretreatment cleaning process, a natural oxide being generated on the wafer surface can be effectively eliminated.