The method of preparing a semiconductor device

The present invention discloses a method for producing a semiconductor device, comprising: providing a substrate, said substrate comprising a first device region and a second device region, said first device region having at least a split-gate type flash memory cell, said split gate surface surrounding said first device-type flash memory cell having a first device region of the oxide layer are sequentially stacked from bottom to top, a first polysilicon layer, the dielectric layer and the second polysilicon layer, the second having a device region sequentially stacked from bottom to top oxide layer and the second device a second polysilicon layer device; etching, the mask layer is etched according to the split-gate type flash memory; in the preparation of the substrate on the mask layer the unit other than the first polycrystalline silicon layer, said dielectric layer and the second polysilicon layer, and selectively etching the second polysilicon layer device. Preparing a semiconductor device according to the present invention, reduced process steps, improve production efficiency, reduce production costs.