Patent ID: 6245681
Filing Date: 2001-06-12
Classification: H01L

Abstract:
A method of forming a device on a semiconductor substrate, comprising the steps of:forming a nitride layer on the semiconductor substrate;providing a first bath of phosphoric acid (H.sub.3 PO.sub.4) comprising phosphorus oxide (P.sub.2 O.sub.5) in a concentration range of greater than about 63 weight %;heating the first bath until the phosphoric acid boils, thereby generating a first bath vapor;recondensing the first bath vapor from the first bath, thereby forming a recondensed first bath vapor;directing the recondensed first bath vapor into the first bath;providing a second bath of phosphoric acid (H.sub.3 PO.sub.4) comprising phosphorus oxide (P.sub.2 O.sub.5) in a concentration range of less than about 58 weight %;heating the second bath until the phosphoric acid boils, thereby generating a second bath vapor;recondensing the second bath vapor from the second bath, thereby forming a recondensed second bath vapor;directing the recondensed second bath vapor into the second bath;etching away part of the nitride layer by placing the semiconductor substrate with the nitride layer into the first bath;removing the semiconductor substrate from the first bath;etching away part of the nitride layer by placing the semiconductor substrate with the nitride layer into the second bath; andremoving the semiconductor substrate from the second bath.