International Business Machines Corporation

Shaun Crawford

Cuc Kim Huynh

Thomas M Wagner

Adam Charles Smith

A Gary Reid

Thomas Benjamin Faure

Timothy Joseph Dalton

Michelle Leigh Steen

James P Levin

A photoresist trimming gas compound is provided which will selectively remove a resist foot or scum from the lower portions of sidewalls of a photoresist. Additionally, the trimmer compound hardens or toughens an upper surface of the photoresist thereby strengthening the photoresist. The trimmer compound includes Oand at least one other gaseous oxide and is typically utilized in a dry etching process after a trench has been formed in a photoresist. The other oxide gases, in addition to the Omay include CO, SOand NO.

Photoresist trimming process

Methods for manufacturing a photomask, such as a chrome on glass photomask and a phase shift photomask are provided. A selective main chrome etch and a selective chrome overetch in the fabrication process provides a photomask having improved image quality and provides nominal image size control and image size uniformity across the photomask within current process flows and manufacturing steps. The selective etch process utilizes a main etch where the resist etch selectivity (amount of chrome removed to resist removed) is higher than in the overetch step in which the etch is more selective to removal of the resist layer relative to the chrome layer. To control the etch selectivities the composition of the etchant chemistry and/or the etchant reactor hardware settings (power, voltage, etc.) can be adjusted.

Method to etch chrome for photomask fabrication

A photoresist trimming gas compound is provided which will selectively remove a resist foot or scum from the lower portions of sidewalls of a photoresist. Additionally, the trimmer compound hardens or toughens an upper surface of the photoresist thereby strengthening the photoresist. The trimmer compound includes Oand at least one other gaseous oxide and is typically utilized in a dry etching process after a trench has been formed in a photoresist The other oxide gases, in addition to the Omay include CO, SOand NO.

A photomask is formed by depositing an opaque layer on a transparent substrate. A resist is formed on the opaque layer and selectively patterned to expose the portions of the opaque layer that are to be etched out. During the dry etching step, the photomask is exposed to an etchant gas mixture which exhibits a selectivity equal to or higher than 1.2:1 between the opaque layer and the resist layer. Due to the selectivity of the gas mixture, a thinner resist film can be used, thereby increasing resolution and accuracy of the opaque layer pattern. Also, due to reduced susceptibility to both a macro-loading effect and a pattern density effect, overetching of the resist and underetching of the opaque layer are significantly reduced, thereby achieving improved etching uniformity and consequently improved CD uniformity.

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Jericho, VT, United States of America

Shaun Crawford