Abstract: A photomask blank includes a hard mask having an excellent etch selectivity with respect to an opaque layer. The photomask blank includes a light-transmissive substrate, an opaque chromium layer disposed on the light-transmissive substrate, and a hard mask layer disposed on the opaque chromium layer. The hard mask layer is of a conductive material having an etch selectivity of at least 3:1 with respect to the opaque chromium layer against an etch gas mixture including chlorine gas and oxygen gas. Also, a resist layer is disposed on the hard mask layer. Alternatively, a phase shift layer can be interposed between the light-transmissive substrate and the opaque chromium layer. Preferably, the hard mask layer is formed of Mo or MoSi. First, the resist layer is patterned, and the hard mask is etched using the patterned resist as an etch mask. Then the chromium layer is etched using the patterned hard mask as an etch mask.

Abstract: A photomask blank includes a hard mask having an excellent etch selectivity with respect to an opaque layer. The photomask blank includes a light-transmissive substrate, an opaque chromium layer disposed on the light-transmissive substrate, and a hard mask layer disposed on the opaque chromium layer. The hard mask layer is of a conductive material having an etch selectivity of at least 3:1 with respect to the opaque chromium layer against an etch gas mixture including chlorine gas and oxygen gas. Also, a resist layer is disposed on the hard mask layer. Alternatively, a phase shift layer can be interposed between the light-transmissive substrate and the opaque chromium layer. Preferably, the hard mask layer is formed of Mo or MoSi. First, the resist layer is patterned, and the hard mask is etched using the patterned resist as an etch mask. Then the chromium layer is etched using the patterned hard mask as an etch mask.

Abstract: A photoresist mask removing method for effectively removing polymers produced as by-products during etching of a metal layer includes processing the polymers prior to removal to facilitate removal thereof. To remove the photoresist mask remaining on a semiconductor substrate after the metal layer is dry-etched in an etching chamber, the semiconductor substrate is preferably conveyed from the etching chamber to an ashing chamber without vacuum break. The semiconductor substrate is pretreated by supplying N2 gas into the ashing chamber under the vacuum state without applying RF power to the ashing chamber to blow the N2 gas on the semiconductor substrate heated up to a predetermined temperature. This pretreatment modifies the polymer by-products to facilitate removal thereof during ashing. The photoresist mask and the polymer by-products are removed by ashing in the ashing chamber.