it is demonstrated that ultra clean technology is a crucial factor in developing high quality processing technology for future ulsi fabrication. only simultaneous establishment of three principles, i.e., ultra clean processing environment, ultra clean wafer surface, and perfect process-parameter control, makes it possible to realize high quality processing. such high quality processing technologies are recognized to be essential for deep submicron ulsi manufacturing. these advanced manufacturing technologies have been demonstrated to be realized by an introduction of a closed manufacturing system where the substrate surfaces are not exposed to the air at any time. typical experimental results related to the closed manufacturing system are described in this article. however, the cost for a high quality manufacturing line must be suppressed to a moderate level standardization is essential to realize this requirement. it is well known that a human brain is an extraordinarily complicated and sophisticated system consisting of approximately 1-2*10/sup 10/ neurons. even with the advancement of present day semiconductor technology, however, only about 10/sup 3/-10/sup 4/ neurons can be implemented on a single chip of silicon. therefore, an enhancement in the integration density by a factor of more than 10/sup 6/ is still demanded in order to construct a practical artificial intelligence system equivalent to a human brain. thus one is not at the pinnacle of semiconductor technology development. rather manufacturers are just standing at the starting point for real semiconductor tech