In order to reduce the ever increasing cost for ULSI manufacturing due to the complexity of integrated circuits, dramatic simplification in the logic LSI architecture as well as the very flexible circuit configuration have been achieved using a highfunctionality device neuron-MOSFET (γMOS).In γMOS logic circuits, however, computations based on the multiple-valued logic is the key for enhancing the functionality. Therefore, much higher accuracy of processing is required. After brief description of the operational principle of γMOS logic, the relationship between the number of multiple logic levels and the functionality enhancement is discussed for further enhancing the functionality of γMOS logic circuits by increasing the number of multiple logic levels, and the accuracy requirements for the manufacturing processes are studied. The order of a few percent accuracy is required for all principal device structural parameters when it is aimed to handle 50-level multiple-valued variable in the γMOS logic circuit.

In order to simulate the mechanism of particle growth by film deposition, imaginary-particle formation method has been newly developed. By using this formation method, the particle size, the particle height and the position of particle on a wafer could be controlled very easily. In this study, the imaginary-particles of various size larger than 0.15 micron and various height were formed on a wafer. By using these imaginary-particles, the effects of a deposition method, a film thickness, a particle size and a particle height upon the particle growth were investigated. As deposition methods, low pressure CVD method, plasma CVD method and sputtering method were compared. As a result, in all deposition method, it's clear that the particle growth doesn't depend on the initial size, and is proportional to the film thickness. Their particle growth rates are characterized by the deposition method, and their values are 1.9, 1.1 and 0.64 in low pressure CVD, plasma CVD and sputtering method, respectively. These values can be explained by the step coverage decided by the deposition method. Furthermore, the particle growth on imaginary-particle was compared with that on the real-particle. It is clear that the growth mechanism of the real-particle is closely similar to that of imaginary-particle, and the study by use of the imaginary-particle is very effective to make clear the mechanism of particle growth. Therefore, the particle size which should be controlled before deposition process is necessary to be decided by counting the particle growth shown in this paper.

The realization of scientific manufacturing of ULSIs in the 21st century will require the development of a technical infrastructure of "Ultra Clean Technology" and the firm establishment of the three principles of high performance processes. Three principles are 1)Ultra Clean Si Wafer Surface, 2)Ultra Clean Processing Environment, and 3)Perfect Parameter controlled process. This paper describes the methods of resolving the problems inherent in Ultra Clean Technology, taking as examples issues in quarter-micron or more advanced semiconductor process and manufacturing equipment, particularly when faced with the challenges of plasma dry etching. Issues indispensable to the development of tomorrow's highly accurate and reliable plasma dry etching equipment are the development of technologies for the accurate measurement of plasma parameters, ultra clean gas delivery systems, chamber cleaning technology on an in-situ basis, and simulating the plasma chemistry.This paper also discusses the standardization of semiconductor manufacturing equipment, which is considered one of the ways to reduce the steep rise in production line construction costs. The establishment of Ultra Clean Technology also plays a vital role in this regard.

Today, defect sources of LSI device mainly lie in the process equipments. The particles generating in these equipments are introduced onto the wafer, and form the defects resulting in functional failures of LSI device. Thus, reducing these particles is acquired for increasing production yield and higher productivity, and it is important to identify the particle source in the equipment. In this study, we discussed new two methods to identify this source in the equipment used in the production line. The important point of identifing is to estimate the particle generation with short time and high accuracy, and to minimize long time stop of the equipment requiring disassembly. First, we illustrated "particle distribution analysis method." In this method, we showed the procedure to express the particle distribution mathematically. We applied this method to our etching equipment, and could identify the particle source without stopping this etching equipment. Secondly, we illustrated the method of "in-situ particle monitoring method," and applied this method to our AP-CVD equipment. As a result, it was clear the main particle source of this equipment and the procedure for decreasing these particles. By using this method, we could estimate the particle generation at real time in process without stopping this equipment. Thus, both methods shown in this study could estimate the particle generation and identify the particle source with short time and high accuracy. Furthermore, they do not require long time stop of the process equipment and interrupting the production line. Therefore, these methods are concluded to be very useful and effective in LSI manufacturing process.