PHASE SHIFT MASK BLANK, PHASE SHIFT MASK, METHOD FOR MANUFACTURING PHASE SHIFT MASK, AND METHOD FOR MODIFYING PHASE SHIFT MASK
Provided are a phase shift mask blank that can sufficiently suppress the formation of haze on a phase shift film surface (on a phase mask), a phase shift mask having reduced haze defects, a method for manufacturing the phase shift mask, and a method for modifying the phase shift mask by electron beam modification etching. A phase shift mask blank ( 10 ) according to an embodiment of the present invention is a phase shift mask blank used for producing a phase shift mask to which exposure light having a wavelength of 200 nm or less is applied, the phase shift mask blank including: a transparent substrate ( 11 ); a phase shift film ( 14 ) formed on the transparent substrate ( 11 ); and a light shielding film ( 15 ) formed on the phase shift film ( 14 ), in which the phase shift film ( 14 ) is a multi-layer phase shift film in which a plurality of the phase layers ( 12 ) and a plurality of the protective layers ( 13 ) are alternately deposited, and a modification etching rate during electron beam modification of the protective layer ( 13 ) is higher than a modification etching rate of the phase layer ( 12 ).
1 . A phase shift mask blank used for producing a phase shift mask to which exposure light having a wavelength of 200 nm or less is applied, the phase shift mask blank comprising:
a transparent substrate;
a phase shift film formed on the transparent substrate; and
a light shielding film formed on the phase shift film,
wherein the phase shift film is a multi-layer phase shift film in which a plurality of phase difference and transmittance adjustment layers that are capable of adjusting a predetermined amount of each of a phase and a transmittance with respect to exposure light to be transmitted and a plurality of protective layers against gas permeation configured to prevent gas permeation to the phase difference and transmittance adjustment layers are alternately deposited, and
a modification etching rate during electron beam modification of the protective layer against gas permeation is higher than a modification etching rate of the phase difference and transmittance adjustment layer.
2 . The phase shift mask blank according to claim 1 ,
wherein the phase shift film has resistance to oxygen-containing chlorine-based etching (Cl/O-based) and is etchable by fluorine-based etching (F-based).
3 . The phase shift mask blank according to claim 1 ,
wherein the phase difference transmittance and adjustment layer contains silicon and contains at least one selected from transition metal, nitrogen, oxygen, and carbon, and
the transition metal is at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, and hafnium.
4 . The phase shift mask blank according to claim 3 ,
wherein a film thickness of each of the phase difference and transmittance adjustment layers is 0.5 nm or more, and
a sum of film thicknesses of the phase difference and transmittance adjustment layers is more than a sum of film thicknesses of the protective layers against gas permeation.
5 . The phase shift mask blank according to claim 1 ,
wherein the protective layer against gas permeation contains at least one selected from tantalum metal, a tantalum compound, tungsten metal, a tungsten compound, tellurium metal, and a tellurium compound.
6 . The phase shift mask blank according to claim 5 ,
wherein a film thickness of each of the protective layers against gas permeation is 0.5 nm or more, and
a sum of film thicknesses of the protective layers against gas permeation is 30 nm or less.
7 . The phase shift mask blank according to claim 5 ,
wherein the tantalum compound contains tantalum and at least one selected from oxygen, nitrogen, and carbon.
8 . The phase shift mask blank according to claim 5 ,
wherein the tungsten compound contains tungsten and at least one selected from oxygen, nitrogen, and carbon.
9 . The phase shift mask blank according to claim 5 ,
wherein the tellurium compound contains tellurium and at least one selected from oxygen, nitrogen, and carbon.
10 . The phase shift mask blank according to claim 1 ,
wherein an outermost layer of the phase shift film is the protective layer against gas permeation.
11 . A phase shift mask having a circuit pattern to which exposure light having a wavelength of 200 nm or less is applied, the phase shift mask comprising:
a transparent substrate;
a phase shift film formed on the transparent substrate; and
a light shielding film formed on the phase shift film,
wherein the phase shift film is a multi-layer phase shift film in which a plurality of phase difference and transmittance adjustment layers that are capable of adjusting a predetermined amount of each of a phase and a transmittance with respect to exposure light to be transmitted and a plurality of protective layers against gas permeation configured to prevent gas permeation to the phase difference and transmittance adjustment layers are alternately deposited, and
a modification etching rate during electron beam modification of the protective layer against gas permeation is higher than a modification etching rate of the phase difference and transmittance adjustment layer.
12 . The phase shift mask according to claim 11 ,
wherein the phase shift film has resistance to oxygen-containing chlorine-based etching (Cl/O-based) and is etchable by fluorine-based etching (F-based).
13 . The phase shift mask according to claim 11 ,
wherein the phase difference and transmittance adjustment layer contains silicon and contains at least one selected from transition metal, nitrogen, oxygen, and carbon, and
the transition metal is at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, and hafnium.
14 . The phase shift mask according to claim 13 ,
wherein a film thickness of each of the phase difference and transmittance adjustment layers is 0.5 nm or more, and
a sum of film thicknesses of the phase difference and transmittance adjustment layers is more than a sum of film thicknesses of the protective layers against gas permeation.
15 . The phase shift mask according to claim 11 ,
wherein the protective layer against gas permeation contains at least one selected from tantalum metal, a tantalum compound, tungsten metal, a tungsten compound, tellurium metal, and a tellurium compound.
16 . The phase shift mask according to claim 15 ,
wherein a film thickness of each of the protective layers against gas permeation is 0.5 nm or more, and
a sum of film thicknesses of the protective layers against gas permeation is 30 nm or less.
17 . The phase shift mask according to claim 15 ,
wherein the tantalum compound contains tantalum and at least one selected from oxygen, nitrogen, and carbon.
18 . The phase shift mask according to claim 15 ,
wherein the tungsten compound contains tungsten and at least one selected from oxygen, nitrogen, and carbon.
19 . The phase shift mask according to claim 15 ,
wherein the tellurium compound contains tellurium and at least one selected from oxygen, nitrogen, and carbon.
20 . The phase shift mask according to claim 11 ,
wherein an outermost layer of the phase shift film is the protective layer against gas permeation.
21 . A method for manufacturing a phase shift mask using the phase shift mask blank according to claim 1 , the method comprising:
forming a light shielding film on the phase shift film;
forming a resist pattern on the light shielding film;
forming a pattern on the light shielding film by oxygen-containing chlorine-based etching (Cl/O-based) after forming the resist pattern;
forming a pattern on the phase shift film by fluorine-based etching (F-based) after forming the pattern on the light shielding film;
removing the resist pattern after forming the pattern on the phase shift film; and
removing the light shielding film by oxygen-containing chlorine-based etching (Cl/O-based) from the phase shift film after removing the resist pattern.
22 . A method for modifying the phase shift mask by electron beam modification etching according to claim 11 , the method comprising:
surface-oxidizing each of the protective layers against gas permeation immediately before modifying the protective layers against gas permeation.