Lithography is widely recognized as one of the key steps in the manufacture of ICs and other devices and/or structures. However, as the dimensions of features made using lithography become smaller, lithography is becoming a more critical factor for enabling miniature IC or other devices and/or structures to be manufactured. As explained above, to make it happen, many other important technologies will have to be addressed. The vacuum technology is one of them and the engineers and experts are paying attention on vacuum technology including vacuum pumps. Especially high Vacuum(HV) and Ultra high vacuum(UHV) are not easy and not simple one. So the manpower who can understand vacuum technology with long experience in vacuum industry is important with basic study.