Mask for manufacturing semiconductor device and method of manufacture thereof

An optical mask production method for manufacturing an optical mask, for a phase shifting projection exposure method for transferring a circuit pattern, on a first major surface of a transparent mask substrate, onto a photoresist film on an integrated circuit wafer through an optical projection system by exposing the mask to a monochromatic exposure light beam, the optical mask production method comprising the steps of:

• directing a focused ion beam from the first major surface side of the mask substrate, to a first machining region to become a second light transmission region of the optical mask, the optical mask also having a first light transmission region and a light shield region, the focused ion beam forming a recess region having a flat bottom and a predetermined depth.

A method of processing a mask at an intended region of the mask where a shifter pattern is intended to be formed on a mask substrate, comprising etching the substrate at the intended region with an ion beam, to form an etched region, the etching being performed to a depth such that the phase of light passing through the etched region is opposite to the phase of light passing through transparent regions of the substrate where no shifter patterns are formed.

A method of processing a phase shifting mask at an intended region of the mask where a shifter element of the mask substrate is intended to be formed, comprising the step of etching the substrate in the intended region with an ion beam to a depth corresponding to the product of half the wavelength of light passing through the etched region and an odd integer, to form an etched region, whereby light passing through the etched region interferes with and is cancelled by light passing through other elements of the phase shifting mask.

A method of processing a mask at a transparent region of a phase shifting mask where a shifter pattern is to be formed, the shifter pattern to be provided at a mask substrate, comprising etching the mask substrate at the transparent region, in accordance with mask pattern data, with a focused ion beam, to a depth such that a phase of light passing through the etched region is substantially opposite to a phase of light passing through transparent regions of the substrate where no shifter patterns are formed.

A method of processing a phase shifting mask where a shifter element of the mask substrate is to be formed, comprising etching the substrate in a first region, in accordance with mask pattern data, with a focused ion beam to a depth substantially corresponding to the product of half the wavelength of light passing through the etched region and an odd integer, whereby light passing through the first region interferes with and is cancelled by light passing through other elements, than the shifter element, of the phase shifting mask.

An optical mask production method for manufacturing an optical mask, for a phase shifting projection exposure method for transferring a circuit pattern, on a first major surface of a transparent mask substrate, onto a photoresist film on an integrated circuit wafer through an optical projection system by exposing the mask to a monochromatic exposure light beam, the optical mask production method comprising the steps of:

• directing a focused ion beam from the first major surface side of the mask substrate, to a first machining region to become a second light transmission region of the optical mask, the optical mask also having a first light transmission region and a metal light shield region, the focused ion beam forming a recess region having a flat bottom and a predetermined depth in accordance with mask pattern data of the metal light shield region.

An optical mask production method for manufacturing an optical mask, for a phase shifting projection exposure method for transferring a circuit pattern, on a first major surface of a transparent mask substrate, onto a photoresist film on an integrated circuit wafer through an optical projection system by exposing the mask to a monochromatic exposure light beam, the optical mask production method comprising the steps of:

• directing a focused ion beam from the first major surface side of the mask substrate, to a first machining region to become a second light transmission region of the optical mask, the optical mask also having a first light transmission region and a light shield region, the focused ion beam forming a transparent region in accordance with mask pattern data of the light shield region.

A method of manufacturing an optical mask, comprising the steps of:

• directing a focused ion beam from a first major surface side of a substrate of the optical mask toward the substrate, to a first machining region to be a second light transmission region of the optical mask, the second light transmission region shifting a phase of light transmitted therethrough such that the light transmitted through the second light transmission region interferes with light transmitted through a first light transmission region of the optical mask, during use of the optical mask, whereby a clear real image is made;
• and
• forming a recess region, having a flat bottom and a predetermined depth, in said second transmission region, by said focused ion beam.