Seamless Integration of W Etch Back Processes on an Asher
Original Publication Date: 2004-Jul-25
Included in the Prior Art Database: 2004-Jul-25
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A sub-process in the production of ICs (Integrated Circuits) is to create the structures of a semiconductor by an etch operation. An ash tool can be used to remove an organic resist mask used for semiconductor structuring or selective implantation to create the desired electrical devices. This resist removal step typically follows an etch or an implant operation and is typically performed using an Oxygen based plasma. Certain ash chambers also work with CF4 to remove undesirable polymers and metallic residues from the wafer. If an ash tool facilitated with CF4 is used to remove the metal residues mentioned, the negative impact is that the non-volatile metal etch residues in the process chamber will poison the chamber resulting in a severely depressed capability to strip the resist (the strip rate can be reduced up to 30% of the nominal value). Also, the residual metal etch reaction products can be transferred from the process chamber back onto the wafers since the same chamber could be used to support both standard strip as well as metal etch operations. This cross-contamination can seriously affect the electrical reliability of the semiconductor devices being fabricated.