Study On The Fabrication And The Applications Of Nano X-ray Imaging And Microscopy Optics

Because of X-ray's short wave length,deep penetration,and various image mechanisms(such as absorption,phase,fluorescence,etc.),X-ray imaging and microscope technique has the potential of imaging the thick samples with nanoscal spatial resolution.It can observe and analyze varieties of micro-physics,chemical phenomenon and nano-structures.The three-dimensional internal observation of thick materials will have a wide range of applications in the biomedical and materials science.So the X-ray imaging and microscope technique is received an increasing attention.The core optical elements of X-ray imaging and microscope are Fresnet zone plates and grating.Because of their complex fabrication processes and expensive price,the development of X-ray imaging and microscope is restricted in our country. In this thesis,the X-ray imaging zone plates and grating,which have the worldwide applications in the X-ray imaging and microscope technique,are fabricated by electron-beam lithography and X-ray lithography techniques.The X-ray imaging zone plates,which has the outermost zone width of 100 nm and the thickness of 700 nm and 1300 nm,has been fabricated by electron-beam lithography,X-ray lithography, and gold electroplating techniques.Using the same fabrication processes,the X-ray transmission grating,which has the line density of 3333 1/mm and the thickness of 1000 nm,has been fabricated.Cooperating with the partners,a series of new optical devices,such as photonic crystals,chiral structures and amplitude modulation zone plates,have been fabricated.This thesis focuses in the following areas:1.The principles and methods of X-ray imaging and microscope technique have been introduced.Based on the domestic development of X-ray imaging and microscope technique,the National Synchrotron Radiation Laboratory(NSRL)has constructed a beamline and experimental station.The design,computing and simulation of X-ray imaging and microscope beamline and experimental station have been showned in this thesis.The measured parameters of X-ray imaging and microscope beamline and experimental station showed they are reaching the desirously aim.The spatial resolution of the experiment stations reaches 50 nm. So the X-ray imaging and microscope beamline and experimental station can be applied in the phase contrast imaging and three-dimensional CT imaging. 2.The parameters of zone plates,working principle,structure and other features have been introduced.The spatial resolution and diffraction efficiency,which are the two most important parameters in X-ray imaging and microscope,have been simulated.According to the needs of X-ray imaging and microscope,the main parameters of the zone plates have been designed.3.For the special structures of X-ray imaging zone plates and grating,a method of fabricating zone plates and grating has been developed in NSRL.Firstly,the zone plates and grating masks have been fabricated by electron-beam lithography and gold electroplating techniques.Secondly,the high-aspect-ratio zone plates and grating have been replicated by X-ray lithography and gold electroplating techniques.This method which makes full use of the electron-beam lithography can generate high-resolution patterns,and X-ray lithography can replicate high-aspect-ratio nano-structures.The e-beam exposure system,the proximity effect during electron beam exposure,and the stitchment of fabricating large field, have also been discussed.The X-ray exposure masks of zone plates and grating, which have the outermost zone width of 100 nm and the line density of 3333 1/mm respectively,have been fabricated.Based on electron-beam lithography and ion beam etching,a series of micro-nano-optical devices,such as chiral device, amplitude modulation zone plates,have also been fabricated.4.Based on the simulations of the masks and samples with various distances,using the whole-water environment method,the zone plates that have outermost zone width of 100 nm and thickness of 700 nm and 1300 nm,the X-ray transmission grating that have pitch of 300 nm,line density of 3333 I/mm,and the thickness of 1000 nm,have been fabricated.It's the first time to characterize the zone plate's structures by X-ray imaging and microscope.Using the X-ray imaging and microscope technique to characterize the nano-structures in water environment has been suggested.Using the same processes,a series of optical devices such as photonic crystals have been successfully fabricated.5.Based on the principle of first diffraction efficiency of zone plates,the theoretical first diffraction efficiency of gold zone plates in 7.5 keV X-ray energy has been computed.The diffraction efficiency test method,optical sketch and instrumentation have been showed.The test experiment was carried out at the X-ray diffraction and scattering experiments station in NSRL.The two zone plates that with outermost zone width of 100 nm and thickness of 700 nm have been tested.The zone plates' first diffraction efficiency is 8.63%in the 7.5 keV X-ray energy,which is similar with the theoretical diffraction efficiency.The innovations of this thesis:1.Based on the domestic development of X-ray imaging and microscope technique and the characteristics of Hefei Light Source,the X-ray imaging and microscope beamline and experimental station have been designed.2.During the processes of fabricating zone plates and the grating masks,we use geometric correction and dose correction methods to eliminate the proximity effection.The zone plates with outermost zone width of 100 nm and thickness of 250 nm and the X-ray transmission grating with line density of 3333 1/mm and the thickness of 250 nm have been fabricated by electron beam lithography and micro electroplating technique.3.By the method of whole-water electroplating environment,the zone plates with the outermost zone width 100 nm,profile thickness of 700 nm and 1300 nm have been successfully fabricated by combining X-ray lithography with micro-plating technique.It's the first time to characterize the zone plates' internal structurees by X-ray imaging and microscope technique.Nano-structure can be observed by X-ray imaging and microscope technique in the water environment.4.By using electron beam lithography,X-ray lithography and micro-electroplating technique,the X-ray transmission grating with 3333 1/mm and the thickness of 1000 nm have been successfully fabricated.