Reflective extreme ultraviolet mask and method of manufacturing the same
A reflective EUV mask and a method of manufacturing the same, the reflective EUV mask including a mask substrate having an exposing region and a peripheral region, the mask substrate including a light scattering crystalline portion that scatters light incident to the peripheral region and that decreases reflectivity of the peripheral region; a reflective layer on an upper surface of the mask substrate, the reflective layer having a first opening that exposes the crystalline portion; and an absorbing layer pattern on an upper surface of the reflective layer, the absorbing layer pattern having a second opening in fluidic communication with the first opening.
1. A reflective EUV mask, comprising:
a mask substrate having an exposing region and a peripheral region, the mask substrate including a light scattering crystalline portion that scatters light incident to the peripheral region and that decreases reflectivity of the peripheral region;
a reflective layer on an upper surface of the mask substrate, the reflective layer having a first opening that exposes the crystalline portion; and
an absorbing layer pattern on an upper surface of the reflective layer, the absorbing layer pattern having a second opening in fluidic communication with the first opening.
2. The reflective EUV mask as claimed in claim 1 , wherein the crystalline portion has a crystalline facet substantially parallel with an incident direction of the light.
3. The reflective EUV mask as claimed in claim 1 , wherein the reflective layer includes an alternately stacked silicon layer and molybdenum layer.
4. The reflective EUV mask as claimed in claim 1 , wherein the absorbing layer pattern includes:
an EUV absorbing layer pattern on the upper surface of the reflective layer; and
a DUV absorbing layer pattern on an upper surface of the EUV absorbing layer pattern.
5. The reflective EUV mask as claimed in claim 4 , wherein the EUV absorbing layer pattern includes a tantalum boron nitride layer.
6. The reflective EUV mask as claimed in claim 4 , wherein the DUV absorbing layer pattern includes a tantalum boron oxide layer.
7. The reflective EUV mask as claimed in claim 1 , wherein the absorbing layer pattern includes an exposing pattern in the exposing region.
8. A method of manufacturing a reflective EUV mask, the method comprising:
forming a reflective layer on an upper surface of a mask substrate, the substrate including an exposing region and a peripheral region;
forming an absorbing layer on an upper surface of the reflective layer;
etching the reflective layer and the absorbing layer in the peripheral region to form:
a first opening in the reflective layer, the first opening exposing the upper surface of the mask substrate, and
an absorbing layer pattern having a second opening in fluidic communication with the first opening; and
forming a crystalline portion at a portion of the upper surface of the mask substrate exposed through the first opening and the second opening such that the crystalline portion scatters light incident to the peripheral region and decreases reflectivity of the peripheral region.
9. The method as claimed in claim 8 , wherein forming the crystalline portion includes converting portions of the upper surface of the mask substrate in an amorphous state into a crystalline state.
10. The method as claimed in claim 9 , wherein converting the amorphous state into the crystalline state includes irradiating a laser to the upper surface of the mask substrate.
11. The method as claimed in claim 10 , wherein the laser is irradiated in a direction substantially parallel with an incident direction of the light and provides the crystalline portion with a crystalline facet substantially parallel with the incident direction of the light.
12. The method as claimed in claim 8 , wherein forming the absorbing layer includes:
forming an EUV absorbing layer on the upper surface of the reflective layer; and
forming a DUV absorbing layer on an upper surface of the EUV absorbing layer.
13. The method as claimed in claim 8 , wherein forming the absorbing layer pattern further includes etching the absorbing layer in the exposing region to form an exposing pattern.
14. The method as claimed in claim 13 , wherein the exposing pattern is formed simultaneously with the second opening.
15. A reflective EUV mask, comprising:
a mask substrate having an exposing region and a peripheral region, the mask substrate including a light scattering crystalline portion in the peripheral region;
a reflective layer on an upper surface of the mask substrate, the reflective layer including a first opening therethrough, the first opening overlying the crystalline portion of the mask substrate; and
an absorbing layer pattern on an upper surface of the reflective layer, the absorbing layer pattern having a second opening therethrough, the second opening overlying the first opening.
16. The reflective EUV mask as claimed in claim 15 , wherein the crystalline portion has a crystalline facet that is substantially perpendicular to an upper surface of the mask substrate.
17. The reflective EUV mask as claimed in claim 16 , wherein the crystalline portion is configured to scatter light incident to the peripheral region and to decrease reflectivity of the peripheral region.
18. The reflective EUV mask as claimed in claim 17 , wherein the crystalline portion is configured to scatter light having a wavelength of about 100 nm to about 400 nm.