There is provided a phase shift mask for extreme-ultraviolet lithography and a method of manufacturing the phase shift mask. The phase shift mask includes a substrate, a reflective layer, device patterns, a frame pattern, or phase shift patterns. The frame pattern is a pattern that includes alignment holes exposing portions of the reflective layer. The phase shift patterns overlap with the device patterns.

There is provided a phase shift mask for extreme-ultraviolet lithography and a method of manufacturing the phase shift mask. The phase shift mask includes a substrate, a reflective layer, device patterns, a frame pattern, or phase shift patterns. The frame pattern is a pattern that includes alignment holes exposing portions of the reflective layer. The phase shift patterns overlap with the device patterns.

A lithography mask including a substrate, a phase shift layer on the substrate and an etch stop layer is provided. The phase shift layer is patterned and the substrate is protected from etching by the etch stop layer. The etch stop layer can be a material that is semi-transmissive to light used in photolithography processes or it can be transmissive to light used in photolithography processes.

An extreme ultraviolet lithography (EUVL) method includes providing at least two phase-shifting mask areas having a same pattern. A resist layer is formed over a substrate. An optimum exposure dose of the resist layer is determined, and a latent image is formed on a same area of the resist layer by a multiple exposure process. The multiple exposure process includes a plurality of exposure processes and each of the plurality of exposure processes uses a different phase-shifting mask area from the at least two phase-shifting mask areas having a same pattern.

An extreme ultraviolet lithography (EUVL) method includes providing at least two phase-shifting mask areas having a same pattern. A resist layer is formed over a substrate. An optimum exposure dose of the resist layer is determined, and a latent image is formed on a same area of the resist layer by a multiple exposure process. The multiple exposure process includes a plurality of exposure processes and each of the plurality of exposure processes uses a different phase-shifting mask area from the at least two phase-shifting mask areas having a same pattern.

A photoresist film is patterned into an array of island shapes with improved critical dimension uniformity and no phase edges by using two alternating phase shifting masks (AltPSMs) and one post expose bake (PEB). The photoresist layer is exposed with a first AltPSM having a line/space (L/S) pattern where light through alternating clear regions on each side of an opaque line is 180° phase shifted. Thereafter, there is a second exposure with a second AltPSM having a L/S pattern where opaque lines are aligned orthogonal to the lengthwise dimension of opaque lines in the first exposure, and with alternating 0° and 180° clear regions. Then, a PEB and subsequent development process are used to form an array of island shapes. The double exposure method enables smaller island shapes than conventional photolithography and uses relatively simple AltPSM designs that are easier to implement in production than other optical enhancement techniques.

A photoresist film is patterned into an array of island shapes with improved critical dimension uniformity and no phase edges by using two alternating phase shifting masks (AltPSMs) and one post expose bake (PEB). The photoresist layer is exposed with a first AltPSM having a line/space (L/S) pattern where light through alternating clear regions on each side of an opaque line is 180° phase shifted. Thereafter, there is a second exposure with a second AltPSM having a L/S pattern where opaque lines are aligned orthogonal to the lengthwise dimension of opaque lines in the first exposure, and with alternating 0° and 180° clear regions. Then, a PEB and subsequent development process are used to form an array of island shapes. The double exposure method enables smaller island shapes than conventional photolithography and uses relatively simple AltPSM designs that are easier to implement in production than other optical enhancement techniques.

An alternating phase-shifting mask (Alt-PSM) comprising a 0° phase portion having a first width and a 180° phase portion having a second width greater than the first width. Example differences between the width of the 180° phase portion and the 0° phase portion may be 10 nm, 15 nm, or 20 nm. An Alt-PSM having phase portions of different widths can have an aerial image intensity transmission graph that is symmetric, for example, at 0.2-0.3 intensity.

An alternating phase-shifting mask (Alt-PSM) comprising a 0° phase portion having a first width and a 180° phase portion having a second width greater than the first width. Example differences between the width of the 180° phase portion and the 0° phase portion may be 10 nm, 15 nm, or 20 nm. An Alt-PSM having phase portions of different widths can have an aerial image intensity transmission graph that is symmetric, for example, at 0.2-0.3 intensity.

A method of making a semiconductor structure includes forming a plurality of gate electrodes over a plurality of active regions. The method further includes increasing a width of a portion of each of the plurality of gate electrodes between adjacent active regions of the plurality of active regions, wherein increasing the width of the portion of each of the plurality of gate electrodes comprises increasing the width of less than an entirety of each of the plurality of gate electrodes between the adjacent active regions. The method further includes removing a central region of each of the plurality of gate electrodes, wherein the central region has the increased width, and removing the central region comprises removing less than an entirety of the portion of each of the plurality of gate electrodes.