HIGHLY PURIFIED SILANE GAS FOR ADVANCED SILICON SEMICONDUCTOR-DEVICES

Highly purified SiH4 gas is required for manufacturing silicon semicon ductor devices (e.g., the formation of Si-single crystal, poly-Si, Si3 N4, and siliside thin films. We have newly established a technology fo r delicately measuring impurities in Sill, gas by using a modified atm ospheric pressure ionization mass spectrometer equipped with a two-com partment ion source, with a lower detection limit around 0.1 to 1 ppb. We have succeeded in establishing the quantitative analysis method fo r disiloxane in SiH4 gas by developing a new technology for generating a Si2H6O standard gas. This is a perfect reaction between H2O and SiH 4 in the reactor. Its lower detection limit is 1 ppb. This analysis te chnology clarified that SiH4 and H2O changed rapidly into molecules co ntaining oxygen atoms in the cylinder or supply tubing system (i.e., d isiloxane, trisiloxane,... and particles). Therefore, this result show s that the impurities in SiH4 gas to be controlled are not H2O but sil oxane and particles. Based on this technology, we have completed devel opment of technology for manufacturing high purity SiH4 gas free from H2O, siloxane, and particles. In addition, we have established a techn ology for delivering highly purified SiH4 gas to the point of use. It is expected that enhanced wafer yield and higher quality thin film wil l be ensured in the silicon semiconductor device manufacturing process .