| 摘要 |
PURPOSE:To form an element insulating groove and an interelement separating groove in one step by forming a stopper layer on the lower region of the element insulating groove. CONSTITUTION:A stopper layer 10 is formed on the lower region of an element insulating groove 15. That is, a lithographic method is used to form a resist mask 14 having holes in an element insulating region and an interelement separating region, and windows are opened in a silicon nitride film 12 and a silicon dioxide film 11 by using the mask. Subsequently, a plasma etching method is used to unidirectionally etch it. This etching is executed deeply in the interelement separating region to arrive at a P-type substrate 1 in the element insulating region, and the groove 15 is formed in the element insulating region, and an interelement separating groove 15 is formed in the interelement separating region. After the mask 14, the films 12, 11 are removed, the grooves 15, 16 are buried with a polycrystalline silicon layer 18 to form a silicon dioxide layer.
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