PURPOSE: To perform taper processing on the side part of a connection hole in a short time without using a high-priced device by forming an SOG film inside an opening hole by a spin on glass method and forming a tapered connection hole while leaving only the side part of this SOG film.
CONSTITUTION: A resist is applied on an interlayer insulating film 2 and after forming an etching mask 3, the interlayer insulating film 2 is given etching by an RIE method using mixed gas of CF4 and H2 so as to form an opening hole 4 of about 2μm on a prescribed spot of the interlayer insulating film 2. Next, the etching mask 3 is removed and SOG is applied while turning it on the interlayer insulating film 2 by the spin on glass method followed by firing to form an SOG film 5. Consequently, SOG enters the recessed part of the opening hole 4 so as to form the tapered SOG film 5 on the side walls. Next, the SOG film 5 is etched back by the RIE method. At this time, etching speed is different depending on the direction so that the peripheral part of the SOG film 5 remains as a tapered part 5b when the base of the SOG film 5 is completely removed so as to form a connection hole 6.
IWAMORI TOSHIMICHI
TEZUKA HIROAKI
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