Browse Prior Art Database

Seamless Integration of W Etch Back Processes on an Asher

IP.com Disclosure Number: IPCOM000028835D
Original Publication Date: 2004-Jul-25
Included in the Prior Art Database: 2004-Jul-25
Document File: 1 page(s) / 20K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

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.

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Seamless Integration of W Etch Back Processes on an Asher

Idea: Srivatsa Kundalgurki, DE-Dresden

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.

The core of a new idea is to utilize a N2/CF4 plasma for the controlled etch of Tungsten or other metals

in a chamber typically used for stripping the resist. This chemical mixture is more effectiv...