Gas flow control is important factor that influences the concentration of process gas and the pressure of the process chamber. In manufacturing processes that use metal organic (MO) gases, a system that controls the flow rate of MO gas must be developed to improve film performance and the reliability of film formation. We have developed a high temperature flow control system based on pressure measurements (HT-FCS) to control the flow rate of MO gas. Moreover, a liquid source control system that combines a HT-FCS and vaporizer was developed. Using this system, it was possible to control the flow rate of MO gas with high accuracy for extended periods. A flow control system that can supply MO gas with a stable flow rate by vaporizing MO material with the quantity needed at each time has been realized.

After confirming the basic characteristics of two types of metal gasket fittings, which are used in construction of ultrapure gas delivery systems for semiconductor manufacturing, it is noticed that the pipe usually twists at the time the fitting is tightened. This may be the possible cause of an external leak, therefore a twist leak test was undertaken to confirm the reliability of the seal during assembly. As a result, it was found that one type of fitting leaked and another type of fitting did not leak. This later type did not leak (leak rate is less than 2.98×10−16 Pa m3/s) even after 70° of twisting.

Semiconductor devices are manufactured from Silicon wafers via diverse processes and application-specific equipment that requires supply of various gases. The gas supply system consists of pressure regulators, pressure gauges, filters, flow controllers, valves, fittings etc. The valves in this system are important parts for controlling and stopping the flow of gases. A wide variety of valves are used throughout the industrial world, but those used for semiconductor manufacturing require special features such as external leak-free, particle-free and dead space-free, because the extremely fine patterns formed on the high grade wafers are made with ultrapure process gases. In addition to these features, the valves must be durable enough to operate several tens of millions of cycles because of faster processing requirements with ALD applications. This research work was done to develop a highly durable diaphragm valve and to verify its durability performance via stress analysis.

Slow Start Safety Cylinder Valve (S3V) has been developed to inhibit adiabatic compression. S3 V can control to increase the pressure slower than conventional pneumatic valve (PV) during the secondary pressure goes up, so that it can inhibit adiabatic compression and decomposition of oxidized gases. We have confirmed that S3 V achieved lower temperature than PV by adiabatic compression theoretically and experimentally. Therefore, S3V is convenient to secure from accidents for oxidized gases in semiconductorfabs.