The purity of wafer surfaces is an essential requisite for the successful fabrication of VLSI and ULSI silicon circuits. Wafer cleaning chemistry has remained essentially unchanged in the past 25 years and is based on hot alkaline and acidic hydrogen peroxide solutions, a process known as "RCA Standard Clean." This is still the primary method used in the industry. What has changed is its implementation with optimized equipment: from simple immersion to centrifugal spraying, megasonic techniques, and enclosed system processing that allow simultaneous removal of both contaminant films and particles. Improvements in wafer drying by use of isopropanol vapor or by "slow-pull" out of hot deionized water are being investigated. Several alternative cleaning methods are also being tested, including choline solutions, chemical vapor etching, and UV/ozone treatments. The evolution of silicon wafer cleaning processes and technology is traced and reviewed from the 1950s to August 1989.

No abstract

No abstract

No abstract

A review is presented of deposition processes for forming dielectric passivation layers on silicon semiconductor devices, with emphasis on recent advances in this field. Materials of prime interest are thin-film dielectrics used as secondary passivants deposited by several types of chemical vapor deposition (CVD) processes. The fundamental principles, deposition parameters, advantages, applicability, and limitations of the various types of CVD for dielectric passivation films are described and compared. The CVD processes discussed include low- and high-temperature CVD at normal pressure, and the relatively new technologies about to emerge for large-scale applications−low-pressure CVD at low and high temperatures, and plasma-enhanced CVD.