Selective Conversion Of Films To Facilitate Delineation
Original Publication Date: 1979-May-01
Included in the Prior Art Database: 2005-Feb-20
At present, it is conventional to subetch polysilicon lands using HFHNO(3)-HAC solutions and, to a lesser extent, KOH. Such solutions must be very closely controlled in etch times to prevent the undesirable attack of underlying silicon dioxide and silicon structures and undercutting of the polysilicon land itself. It is known that such attack can reduce the yield of good circuits and create reliability problems, especially in MOSFET memory circuits.