Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.