Antireflection film, optical element with antireflection film, and production method of the antireflection film

An antireflection film comprising:

• an alternately multilayered film having a designed center wavelength λ0 in a range of wavelengths 190 nm to 250 nm and comprising high-index layers of a refractive index nh and low-index layers of a refractive index nl in order from the side of a substrate to the side of air, said alternately multilayered film having a five-layered structure, wherein when a refractive index of the substrate is n, the refractive indices satisfy the following conditions;
• 1.35≦nl≦1.45
• 1.60≦nh≦1.85
• nl≦n≦nh;
• and
• wherein where optical thicknesses (refractive index x geometrical thickness) of the respective layers are represented by d1, d2, d3, d4, and d5 in order from the first layer to the fifth layer when counted from the substrate side, the first layer, the third layer, and the fifth layer are the low-index layers, the second layer and the fourth layer are the high-index layers, and the optical thicknesses satisfy the following conditions:
• 0.42 λ0≦d1≦0.47 λ0
• 0.37 λ0≦d2≦0.42 λ0
• 0.37 λ0≦d3≦0.42 λ0
• 0.20 λ0≦d4≦0.25 λ0
• 0.20 λ0≦d5≦0.25 λ0.

An antireflection film comprising:

• an alternately multilayered film having a designed center wavelength λ0 in a range of wavelengths 190 nm to 250 nm and comprising high-index layers of a refractive index nh and low-index layers of a refractive index nl in order from the side of a substrate to the side of air, said alternately multilayered film having a six-layered structure, wherein when a refractive index of the substrate is n, the refractive indices satisfy the following conditions;
• 1.35≦nl≦1.45
• 1.60≦nh≦1.85
• nl≦n≦nh;
• and
• wherein where optical thicknesses (refractive index x geometrical thickness) of the respective layers are represented by d1, d2, d3, d4, d5, and d6 in order from the first layer to the sixth layer when counted from the substrate side, the first layer, the third layer, and the fifth layer are the high-index layers, the second layer, the fourth layer, and the sixth layer are the low-index layers, and the optical thicknesses satisfy the following conditions:
• 0.40 λ0≦d1≦0.45 λ0
• 0.37 λ0≦d2≦0.42 λ0
• 0.45 λ0≦d3≦0.50 λ0
• 0.04 λ0≦d4≦0.09 λ0
• 0.28 λ0≦d5≦0.33 λ0
• 0.20 λ0≦d6≦0.25 λ0.

An optical element for use in projecting a rectile pattern onto a semiconductor wafer, wherein said element is coated with an antireflection film comprised of an alternately multilayered film having a center wavelength λO in the range of 190 nm to 250 nm and comprised of high-index layers of a refractive index nh, composed of Al2O3 as the principal component, and low-index layers of a refractive index nl, composed of MgF2 or AlF3 as the principal component, in that order, from the side of a substrate to the side of air, the alternately multilayered film having a four-layered structure, wherein when the substrate has a refractive index n, the other said refractive indices satisfy the following conditions:

• 1.35≦nl≦1.45,
• 1.60≦nh≦1.85, and
• nl≦n≦nh;
• and
• wherein when the optical thicknesses (refractive index x geometrical thickness) of the respective layers are represented by d1, d2, d3, and d4, in order from the first layer to the fourth layer when counted from the substrate side, the first layer and the third layer are the high-index layers, the second layer and the fourth layer are the low-index layers, and said optical thicknesses satisfy the following conditions:
• 0.38 λO≦d1≦0.43 λO
• 0.38 λO≦d2≦0.43 λO,
• 0.20 λO≦d3≦0.25 λO,
• 0.20 λO≦d4≦0.25 λO.

An optical element for use in projecting a rectile pattern onto a semiconductor wafer, wherein said element is coated with an antireflection film comprised of an alternately multilayered film having a center wavelength λO in the range of 190 nm to 250 nm and comprised of high-index layers of a refractive index nh, composed of Al2O3 as the principal component, and low-index layers of a refractive index nl, composed of MgF2 or AlF3 as the principal component, in that order, from the side of a substrate to the side of air, the alternately multilayered film having a five-layered structure, wherein when the substrate has a refractive index n, the other said refractive indices satisfy the following conditions:

• 1.35≦nl≦1.45,
• 1.60≦nh≦1.85, and
• nl≦n≦nh;
• and
• wherein when the optical thicknesses (refractive index x geometrical thickness) of the respective layers are represented by d1, d2, d3, d4, and d5, in order from the first layer to the fifth layer when counted from the substrate side, the first layer, the third layer, and the fifth layer are the low-index layers, the second layer and the fourth layer are the high-index layers, and said optical thicknesses satisfy the following conditions:
• 0.42 λO≦d1≦0.47 λO,
• 0.37 λO≦d2≦0.42 λO,
• 0.37 λO≦d3≦0.42 λO,
• 0.20 λO≦d4≦0.25 λO, and
• 0.20 λO≦d5≦0.25 λO.

An optical element for use in projecting a rectile pattern onto a semiconductor wafer, wherein said element is coated with an antireflection film comprised of an alternately multilayered film having a center wavelength λO in the range of 190 nm to 250 nm and comprised of high-index layers of a refractive index nh, composed of Al2O3 as the principal component, and low-index layers of a refractive index nl, composed of MgF2 or AlF3 as the principal component, in that order, from the side of a substrate to the side of air, the alternately multilayered film having a six-layered structure, wherein when the substrate has a refractive index of n, the other said refractive indices satisfy the following conditions:

• 1.35≦nl≦1.45,
• 1.60≦nh≦1.85,
• nl≦n≦nh;
• and
• wherein when the optical thicknesses (refractive index x geometrical thickness) of the respective layers are represented by d1, d2, d3, d4, d5, and d6, in order from the first layer to the sixth layer when counted from the substrate side, the first layer, the third layer, and the fifth layer are the high-index layers, the second layer, the fourth layer, and the sixth layer are the low-index layers, and said optical thicknesses satisfy the following conditions:
• 0.40 λO≦d1≦0.45 λO,
• 0.37 λO≦d2≦0.42 λO,
• 0.45 λO≦d3≦0.50 λO,
• 0.04 λO≦d4≦0.09 λO,
• 0.28 λO≦d5≦0.33 λO, and
• 0.20 λO≦d6≦0.25 λO.

A method for producing a four-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing by vacuum evaporation on a substrate having a refractive index of n a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.38 λO to 0.43 λO;
• (c) depositing by vacuum evaporation on said first high-index layer a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.38 λO to 0.43 λO;
• (d) depositing by vacuum evaporation on said first low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO;
• and
• (e) depositing by vacuum evaporation on said second high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO.

A method for producing a five-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing by vacuum evaporation on a substrate having a refractive index of n a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.42 λO to 0.47 λO;
• (c) depositing by vacuum evaporation on said first low-index layer a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (d) depositing by vacuum evaporation on said first high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λ0 to 0.42 λ0;
• (e) depositing by vacuum evaporation on said second low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO;
• and
• (f) depositing by vacuum evaporation on said second high-index layer a third low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO.

A method for producing a six-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing by vacuum evaporation on a substrate having a refractive index of n a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.40 λO to 0.45 λO;
• (c) depositing by vacuum evaporation on said first high-index layer a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (d) depositing by vacuum evaporation on said first low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.45 λO to 0.50 λO;
• (e) depositing by vacuum evaporation on said second high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.04 to 0.09 λO;
• (f) depositing by vacuum evaporation on said second low-index layer a third high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.28 λO to 0.33 λO;
• and
• (g) depositing by vacuum evaporation on said third high-index layer a third low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO.

A method for producing a four-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on a substrate having a refractive index of n, a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.38 λO to 0.43 λO;
• (c) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said first high-index layer a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.38 λO to 0.43 λO;
• (d) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on said first low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO;
• and
• (e) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said second high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO.

A method for producing a five-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on a substrate having a refractive index of n a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.42 λO to 0.47 λO;
• (c) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on said first low-index layer a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (d) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said first high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (e) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on said second low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO;
• and
• (f) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said second high-index layer a third low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO.

A method for producing a six-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on a substrate having a refractive index of n a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.40 λO to 0.45 λO;
• (c) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said first high-index layer a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (d) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on said first low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.45 λO to 0.50 λO;
• (e) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said second high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.04 to 0.09 λO;
• (f) depositing, by sputtering using an aluminum target and a gas containing mainly oxygen, on said second low-index layer a third high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.28 λO to 0.33 λO;
• and
• (g) depositing, by sputtering using an aluminum target and a mixture of an inert gas selected from Ar, He, and Xe and a fluorine-based gas selected from NF3, CF4 and F2, on said third high-index layer a third low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO.

A method for producing a four-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing by chemical vapor deposition on a substrate having a refractive index of n a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.38 λO to 0.43 λO;
• (c) depositing by chemical vapor deposition on said first high-index layer a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.38 λO to 0.43 λO;
• (d) depositing by chemical vapor deposition on said first low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO;
• and
• (e) depositing by chemical vapor deposition on said second high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO.

A method for producing a five-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing by chemical vapor deposition on a substrate having a refractive index of n a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.42 λO to 0.47 λO;
• (c) depositing by chemical vapor deposition on said first low-index layer a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (d) depositing by chemical vapor deposition on said first high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (e) depositing by chemical vapor deposition on said second low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO;
• and
• (f) depositing by chemical vapor deposition on said second high-index layer a third low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 λO to 0.25 λO.

A method for producing a six-layered antireflection film having a center wavelength λO comprising the sequential steps of

• (a) selecting a desired center wavelength for the film in the range of 190 nm to 250 nm;
• (b) depositing by chemical vapor deposition on a substrate having a refractive index of n a first high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.40 λO to 0.45 λO;
• (c) depositing by chemical vapor deposition on said first high-index layer a first low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.37 λO to 0.42 λO;
• (d) depositing by chemical vapor deposition on said first low-index layer a second high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.45 λO to 0.50 λO;
• (e) depositing by chemical vapor deposition on said second high-index layer a second low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.04 to 0.09 λO;
• (f) depositing by chemical vapor deposition on said second low-index layer a third high-index layer composed of Al2O3 as the principal component, said high-index layer having a refractive index that is equal to or greater than n and is within the range of 1.60 to 1.85, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.28 λO to 0.33 λO;
• and
• (g) depositing by chemical vapor deposition on said third high-index layer a third low-index layer composed of MgF2 or AlF3 as the principal component, said low-index layer having a refractive index that is equal to or less than n and is within the range of 1.35 to 1.45, and having an optical thickness (refractive index x geometrical thickness) in the range of 0.20 to 0.25 λO.