Tokyo Electron Limited

Youbun Ito

Masahiro Yamada

Kouichiro Inazawa

Kunihiko Hinata

Abron S Toure

Hiromi Sakima

A lower electrode with the temperature at its mounting surface set at 40&deg; C. is provided inside a processing chamber of an etching apparatus . After a wafer W is placed on the lower electrode , a processing gas with its gas composition and gas flow rate expressed as C F : CH F : Ar&equals;7:4:500 (sccm) is induced into the processing chamber while sustaining the pressure of the atmosphere inside the processing chamber at 50 (mTorr). High-frequency power at 1500 (W) with the frequency at 13.56 (MHz) is applied to the lower electrode to generate plasma. With the plasma thus generated, a carbon film is formed at shoulder of an SiN film layer exposed inside a contact hole and, at the same time, accumulation of carbon at the bottom of the contact hole is prevented, to form a contact hole achieving a high aspect ratio while preventing damage to the SiN film layer.

Etching method

A processing gas constituted of C F , O and Ar achieving a flow rate ratio of 1&lE;C F flow rate/O flow rate&lE;1.625 is supplied into a processing chamber of an etching apparatus and the atmosphere pressure is set within a range of 45 mTorr&tilde;50 mTorr. High-frequency power is applied to a lower electrode sustained within a temperature range of 20&deg; C.&tilde;40&deg; C. on which a wafer W is mounted to raise the processing gas to plasma, and using the plasma, a contact hole is formed at an SiO film on an SiNx film formed at the wafer W. The use of C F and O makes it possible to form a contact hole achieving near-perfect verticality at the SiO film and also improves the selection ratio of the SiO2 film relative to the SiNx film . C F , which becomes decomposed over a short period of time when released into the atmosphere, does not induce the greenhouse effect.

A method and system for processing a substrate in the presence of high purity C F . When processing oxides and dielectrics in a gas plasma processing system, C F is used in combination with a carrier gas (e.g., Ar) and one or more of CO and O . When using a silicon nitride (Si N ) layer as an etch stop, effective etching is performed due to the selectivity of oxides versus silicon nitride. The method is used when etching down to self-aligning contacts and other layers. The method may be practiced with or without using an anti-reflective coating underneath the photoresist layer.

Etchant for use in a semiconductor processing method and system

A method and system for processing a substrate in the presence of high purity C.sub.5 F.sub.8. When processing oxides and dielectrics in a gas plasma processing system, C.sub.5 F.sub.8 is used in combination with a carrier gas (e.g., Ar) and one or more of CO and O.sub.2. When using a silicon nitride (Si.sub.x N.sub.y) layer as an etch stop, effective etching is performed due to the selectivity of oxides versus silicon nitride. The method is used when etching down to self-aligning contacts and other layers. The method may be practiced with or without using an anti-reflective coating underneath the photoresist layer.

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Youbun Ito