Pellicle for an EUV lithography mask and a method of manufacturing thereof

1. A pellicle for an EUV photo mask comprising:

a frame portion made of Si; and

a membrane disposed on the frame and including at least one metal layer, wherein:

the membrane consisting of equal to or less than five layers or equal to or more than three layers,

the pellicle has an EUV transmittance higher than 85% and smaller than 87.72% and an EUV reflectance lower than 0.25% and greater than 0.01%, at a wavelength of 13.5 nm,

the membrane consists of:

a base membrane layer made of silicon nitride or SiC;

a core layer disposed on the base membrane layer;

a cover layer disposed on the core layer and made of a doped silicon layer;

a first metal layer disposed on the cover layer and made of Mo or Zr; and

a second metal layer disposed on the first metal layer and made of Ru,

a thickness of the core layer is largest in the membrane and in a range from 10 nm to 50 nm,

a thickness of the second metal layer is smaller than a thickness of the first metal layer, and

a thickness of the cover layer is smaller than the thickness of the first metal layer and in a range from 0.5 nm to 10 nm.

2. The pellicle of claim 1 , wherein the EUV transmittance is smaller than 86.88%.

3. The pellicle of claim 1 , wherein the EUV reflectance is lower than 0.20%.

4. The pellicle of claim 1 , wherein the base membrane is made of SiC.

5. The pellicle of claim 1 , wherein the core layer is made of poly silicon or amorphous silicon.

6. The pellicle of claim 1 , wherein, a thickness of the core layer is in a range from 20 nm to 40 nm.

7. A pellicle for an EUV photo mask, comprising:

a frame portion having an opening; and

a membrane disposed on the frame and consisting of five layers, wherein:

the five layers are:

a base membrane layer made of silicon nitride or SiC;

a core layer disposed on the base membrane layer and made of polysilicon or amorphous silicon;

a cover layer disposed on the core layer;

a first metal layer disposed on the cover layer; and

a second metal layer disposed on the first metal layer,

a thickness of the base membrane layer is in a range from 1 nm to 40 nm, and

a thickness of the first metal layer is in a range from 1 nm to 10 nm and greater than a thickness of the second metal layer.

8. The pellicle of claim 7 , wherein the frame portion is made of Si.

9. The pellicle of claim 7 , wherein the cover layer is a silicon nitride layer.

10. The pellicle of claim 7 , wherein the cover layer is a doped region of a Si layer.

11. The pellicle of claim 7 , wherein the second metal layer is a Ru layer.

12. The pellicle of claim 7 , wherein the first metal layer is a Mo layer.

13. The pellicle of claim 7 , wherein the first metal layer is a Zr layer.

14. The pellicle of claim 13 , wherein the second metal layer is a Ru layer.

15. The pellicle of claim 7 , wherein the base membrane is made of SiC.

16. The pellicle of claim 7 , wherein the core layer is made of poly silicon.

17. A pellicle for an EUV photo mask, comprising:

a frame portion having an opening; and

a membrane disposed on the frame and consisting of three layers, wherein:

the three layers are:

a base membrane layer made of SiC;

a first metal layer disposed on the base membrane layer; and

a second metal layer disposed on the first metal layer,

wherein a thickness of the second metal layer is smaller than a thickness of the first metal layer.

18. The pellicle of claim 17 , wherein the second metal layer is a Ru layer.

19. The pellicle of claim 18 , wherein the first metal layer is a Mo layer.

20. The pellicle of claim 18 , wherein the first metal layer is a Zr layer.