HF vapor phase etching (HF/VPE): Production viability for semiconductor manufacturing and reaction model

A nonplasma silicon dioxide etch process using anhydrous hydrogen fluoride at reduced pressures has been investigated. This technique involves the interaction of HF vapor with negative photoresist which catalizes subsequent etching beneath the photoresist. Etching in nonphotoresist coated areas can be eliminated by a short in situ plasma pretreatment followed by HF etching at 190 °C, 10 Torr, and 500 sccm in a commercial etch system. Experimental details as well as a proposed reaction mechanism will be presented.