1.     Introduction

Soft-X ray interference lithography (XIL) is a newly developed technique for production of periodic nano-structures with resolution below 100 nm. The technique is based on coherent radiation obtained from undulators at synchrotron radiation (85-150 eV). Because of its small wavelength (typical value: 13.4 nm) and practical absence of the proximity effect, high density resolution lines/dots with high density can be afforded. The throughput of this parallel exposing method is much higher than that of the serial electron-beam lithography. Interference schemes based on diffraction (gratings) optics have been constructed at BL08U1-B beamline in SSRF. Both one-dimensional and two-dimensional patterns such as arrays of dots have been achieved. XIL is used in a growing number of applications; examples include fabrication of self-assembly templates, magnetic nano-dot arrays and nano-optical components.

2.     Advantage of XIL

   • No proximity effect (e-- mean-free-path < 1-3 nm)
   • No depth of focus: Mask-to-wafer = 0.1 -10 mm
   • Pitch independent aerial image.
   • High resolution: theoretical linewidth limit= 3.5 nm；
   • Large area: up to 0.4x 0.4 mm ²
   • Step and repeat: up to 50x580 mm²
   • High throughput: typically 10 s: 10’ 000x e-beam
   • Quality, reproducibility: enabling industrial operation

3.     Beamline Layout

 

4.     Techniques

Diffraction grating interference lithography：

two grating interference——periodic lines；

three grating interference——periodic hexagonal dots；

four grating interference——periodic square dots；

Resist：PMMA；HSQ；ZEP520.

5.     Representative structures in BL08U1-B

 

6.     Endstations

XIL exposure system including: 100 class clean room, Exposure chamber, Mask & wafer stage, Spin-coater, Microscope, Ellipsometer, UV lithography system and E-beam lithography system.

The main equipments for lithography：Spin coater, UV lithography system and E-beam lithography system.

 

 

7.     Support LAB

This lab is used for pattern transfer, including: E-beam evaporation & magnetron sputtering system with QCM, ICP etching system, laser cutter, Plasma Asher and Ellipsometer.

 

                   

8.     Beamline Specifications

Source	Elliptically Polarized Undulator
EnergyRange	85~150 eV
Photon Flux at sample	1´1015phs/s@300 mA
Beam size at mask	~4´4 mm2
Interference patter period	50 nm
Sing exposure area	~ 0.4´0.4 mm2

9.     Applications

Guided self-assembly templates;

Magnetic nanodot arrays;

Plasmonics and Metamaterials;

EUV resist testing----the only testing equiment for EUV resist in China；

10.  Contacts

Dr Yang,Shumin

Email: yangshumin@sinap.ac.cn

TEL: 86-21-33932085

 

Dr Wu,Yanqing

Email: wuyanqing @sinap.ac.cn

Tel: 86-21-33933208