Methods and etchants for etching oxides of silicon with low selectivity in a vapor phase system

A method for cleaning surfaces, said method comprising:

• forming a first surface situated on a semiconductor substrate, said first surface having exposed doped silicon dioxide;
• forming a second surface situated on a semiconductor substrate, said second surface having exposed refractory metal silicide;
• forming a third surface situated on a semiconductor substrate, said third surface having exposed thermal oxide;
• and
• cleaning said first, second, and third surfaces with a vapor phase solution comprising initiator gas, hydrogen fluoride, and ammonia, and wherein said exposed refractory metal silicide is not substantially etched wherein said vapor phase solution removes thermal oxide at least one-half the rate at which said vapor phase solution removes said doped silicon dioxide and said exposed refractory metal silicide is not substantially removed.

A method for providing containers for container capacitors having reliable contact to a silicon substrate, said method comprising the steps of:

• (a) providing a silicon substrate situated on a semiconductor wafer, said silicon substrate having a layer of doped silicon dioxide formed thereover, said substrate having a source/drain region defined therein;
• (b) forming in said layer of doped silicon dioxide a space for a container capacitor extending down through said layer of doped silicon dioxide to said source/drain region;
• (c) cleaning said source/drain region in a vapor phase solution having an etch rate for thermal oxide of at least one-half of the etch rate of said vapor phase solution for said layer of doped silicon dioxide with an initiator gas, hydrogen fluoride and ammonia;
• (d) depositing a layer of conductive material conformably over said silicon substrate and said layer of doped silicon dioxide to contact said source/drain region;
• and
• (e) removing said layer of conductive material from the top thereof downward to at least the topmost surface of said layer of doped silicon dioxide, leaving in said space a layer for a container capacitor formed of said conductive material.

A method of removing materials situated on a conductor substrate comprising:

• forming a first surface situated on a semiconductor substrate, said first surface having exposed doped silicon dioxide;
• forming a second surface situated on said semiconductor substrate, said second surface having exposed refractory metal silicide;
• forming a third surface situated on said semiconductor substrate, said third surface having exposed thermal oxide;
• and
• exposing said first, second, and third surfaces to a vapor phase solution comprising in the range of about 0.01 PPMV to about 10.sup.4 PPMV initiator gas, about 10.sup.3 PPMV to about 2.times.10.sup.5 PPMV hydrogen fluoride, and about 10.sup.3 PPMV to about 2.times.10.sup.5 PPMV ammonia, wherein said vapor phase solution removes thermal oxide at least one-half the rate at which said vapor phase solution removes said doped silicon dioxide and said exposed refractory metal silicide is not substantially removed.