Abstract: The present invention discloses a method of adding an additional mask in the ion-implantation process. It relates to technical field of ion implantation. This invention comprises: a mask plate is added upon the said MPW and the nitrogen element is implanted in the said MPW; the implanted nitrogen element is used for amorphizing the upper surface of the MPW. The advantageous effects of the above technical solution are as follows: the steps of the production process are simplified; the ion implantation mask will achieve 4 different doping concentrations of the ion implantation when the wafer is implanted. It means that it is possible to form 4 different gate oxide layers of different in thickness. However, it is essential to apply the photomask three times to achieve the same effect in the process of prior art. Consequently, the method of the present invention can reduce both the cost and the term of production process.

Abstract: The present invention is related to the semiconductor manufacturing field, especially a method for monitoring alignment between contact holes and polycrystalline silicon gate by setting a plurality of equidistant contact holes with same sharp on poly-silicon and residual active area, and then obtain the process alignment profile of the quantized values in the plane in order to have a better control of process quality, thereby have a better control of the quality of the process.