| 摘要 |
PURPOSE:To enable an insulating film for isolating elements to be formed by a method wherein after forming polycrystalline silicon film inside grooves, a substrate is oxidized by immersing in mixed solution of water solution of hydrazine or ethylenediamine and alcohol. CONSTITUTION:An epitaxial layer 3 is formed on an Si substrate 1 with a high concentration impurity layer 2 formed thereon and then an SiO2 film 4 and a silicon nitride film 5 are laminated. First, after forming a specific patterned resist film 6 on the substrate 1, U-shape grooves 7 are formed by dry etching process using the resist film 6 as a mask and after removing the resist film 6, innerwalls of grooves 7 are oxidized to form SiO2 films 8 thereon. Second, polycrystalline Si film 9 formed by CVD process is ground to fill up the U-shape grooves. Finally, the substrate 1 so far processed is immersed in a container 22 containing ethylenediamine heated at the temperature of 80 deg.C by a heater 21 or mixed solution of hydrazine and isopropylalcohol to oxidize the polycrystalline Si film 9 formed inside the grooves 7.
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