MANUFACTURING METHOD OF TRIPLE WELL OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming the triple well of a semiconductor device is provided to improve the control of the threshold voltage and the characteristic of punch-through in the device by forming the triple well having the desired doping density and operating independently. CONSTITUTION: A buried n-well(15) is formed on a p-type semiconductor device on which a field oxide film is formed. The buried n-well(15) is narrower than a n-well to be defined on the substrate, and wider than a p-well-2 to be defined on the substrate. Further, the buried n-well(15) connects with the n-well, and separates a p-well and the p-well-2. The n-well is formed on the whole structure by using an n-well mask. The p-well is formed on the whole structure by using a p-well mask. The p-well-2 is formed on the whole structure by using a p-well-2 mask.