METHOD OF CLEANING SUBSTRATE FOR BLANK MASK, SUBSTRATE FOR BLANK MASK, AND BLANK MASK INCLUDING THE SAME

1 . A method of cleaning a substrate for a blank mask comprising:

a first cleaning including irradiating a cleaning target substrate with a pre-treatment light to prepare a substrate cleaned with light; and

a second cleaning including applying a first cleaning solution and a post-treatment light to the substrate cleaned with light to prepare the substrate for the blank mask.

2 . The method of claim 1 , wherein the pre-treatment light is a light with a wavelength of 50 nm to 300 nm.

3 . The method of claim 1 , wherein the post-treatment light is a light with wavelength of 50 nm to 450 nm.

4 . The method of claim 1 , wherein an intensity of the pre-treatment light is 25 mW/cm 2 or more.

5 . The method of claim 1 , wherein the cleaning target substrate is irradiated with the pre-treatment light from two or more light sources.

6 . The method of claim 5 , wherein a UI (Uniform Intensity) value of the pre-treatment light from the two or more light sources according to Equation 1 below is 20% or less:

UI

⁡

(

%

)

=

I

max

-

I

min

I

max

+

I

min

×

100

[

Equation

⁢

1

]

where, in Equation 1, I max is a maximum intensity among intensities of the pre-treatment light from the two or more light sources and I min is a minimum intensity among intensities of the pre-treatment light from the two or more light sources.

7 . The method of claim 1 , wherein the first cleaning is performed in a depressurizing atmosphere.

8 . The method of claim 1 , wherein the cleaning target substrate is disposed in an atmosphere, where an exhaust pressure of 0.01 kPa to 1 kPa is applied.

9 . The method of claim 1 , wherein the first cleaning solution comprises at least one selected from the group consisting of SC-1 (Standard Clean-1) solution, ozone water, ultrapure water, hydrogen water, and carbonated water.

10 . The method of claim 9 , wherein the SC-1 solution is a solution comprising NH 4 OH, H 2 O 2 , and H 2 O.

11 . The method of claim 1 , wherein the substrate cleaned with light is one, from which some or all of compounds absorbing a light with a wavelength of 100 to 190 nm are removed.

12 . The method of claim 1 , wherein the first cleaning solution comprises a hydroxyl radical precursor.

13 . The method of claim 12 , wherein the hydroxyl radical is formed when the first cleaning solution is applied and the post-treatment light is irradiated on the substrate cleaned with light.

14 . The method of claim 1 , wherein the substrate for the blank mask comprises a sulfuric acid ion in an amount of 0 ng/cm 2 to 0.1 ng/cm 2 , a nitric acid ion in an amount of 0 ng/cm 2 to 0.4 ng/cm 2 , a nitrous acid ion in an amount of 0 ng/cm 2 to 0.05 ng/cm 2 , and an ammonium ion in an amount of 0 ng/cm 2 to 1.5 ng/cm 2 , as residual ions measured by an ion chromatography.

15 . The method of claim 1 , wherein the PRE (Particle Removal Efficiency) value of the substrate for the blank mask is 90% or more according to Equation 2 below:

PRE

⁡

(

%

)

=

P

b

-

P

a

P

b

×

100

[

Equation

⁢

2

]

where, in Equation 2, P b is a number of particles measured at the cleaning target substrate and P a is a number of particles measured at the substrate for the blank mask.

16 . A substrate for a blank mask, wherein the substrate is a quartz substrate with a flatness of 0.5 μm or less.

17 . The substrate of claim 16 , wherein the substrate comprises a sulfuric acid ion in an amount of 0 ng/cm 2 to 0.1 ng/cm 2 , a nitric acid ion in an amount of 0 ng/cm 2 to 0.4 ng/cm 2 , a nitrous acid ion in an amount of 0 ng/cm 2 to 0.05 ng/cm 2 , and an ammonium ion in an amount of 0 ng/cm 2 to 1.5 ng/cm 2 , as residual ions measured by an ion chromatography.

18 . The substrate of claim 17 , wherein the substrate comprises a chloride ion in an amount of 0 ng/cm 2 to 0.1 ng/cm 2 , as residual ions measured by the ion chromatography.

19 . A blank mask comprising the substrate for the blank mask of claim 16 .