Ion implantation apparatus.

摘要

An equipment for implanting impurity material ions into a semiconductor wafer is provided with a means to supply acceleration voltage which continuously and automatically changes the acceleration voltage within a predetermined range for the purpose of producing impurity layers having a uniform concentration distribution in the direction of the depth of wafer, and the equipment is effective in making fine patterns of integrated circuits. In one embodiment of the invention, the equipment changes the acceleration voltage continuously so that the frequency of the acceleration voltage is high enough to form a pillar shaped impurity layer at positions in a wafer while the ion beam is irradiated onto the positions respectively thereby to form an impurity layer having a uniform impurity distribution profile.

In another embodiment of the invention, the equipment changes the acceleration voltage continuously but slow enough with respect to the scan frequency so that the ions are implanted to reach a certain depth in the first scan, another depth in the second scan and so on.