Forming And Controlling Technology For The Profile And Microstructure Of Crossed Holographic Photoresist Grating

Crossed grating with periodic structure in two different directions has important scientific research and engineering application value in spectral analysis,laser technology,integrated optics,precision measurement and other technical fields.The microstructure parameters of crossed grating determine its diffraction characteristics,if we could find the technical way to control the profile and microstructure of crossed grating,which would greatly improve the technical level of grating production and broaden its application field.In this paper,basing on the crossed grating,the forming for the profile and microstructure of crossed holographic photoresist grating was studied.The main work is as follows:Firstly,the characteristics of photoresist is studied based on a new experimental research method.The experimental results from the new experimental method is corresponding to the results from the original step experimental method,which verified the rationality and feasibility of using the new experimental method to explore the characteristics of photoresist.Secondly,the profile and microstructure of crossed holographic photoresist grating and the diffraction efficiency of gold-coated crossed grating were studied.The K parameter was introduced to define the bottom profile of the crossed photoresist grating.Basing on the RCWA theory,the gold-coated crossed grating model that is consistent with the groove structure obtained from the experiment was established.The-1st diffraction efficiencies of TE and TM polarized light of the gold-coated crossed grating with the period of 12001ines/mm,the duty cycle range of 0.35 to 0.45,the groove depth of 200nm to 320nm and the parameter K of 0.4 to 0.54 have been searched exactly.The influence of K parameter on diffraction efficiency was studied,and the importance of rigorous control of groove shape in the process of fabricating gold-coated crossed grating was pointed out.Thirdly,forming and control technology for the profile and microstructure of the crossed holographic photoresist grating were studied.We fabricated a series of crossed photoresist grating,then the contrast curves of photoresist with different developer concentration and development time were obtained.A method of two-step development was proposed to control the profile of the crossed photoresist grating.The experiment of two-step develoepment was carried out,and the profile of photoresist grating using two-step development was simulated.The rationality and feasibility of the simulation method of two-step development were analyzed and explained by compareing with the groove measurement results of the grating obtained from experiment.The effective profile control of crossed holographic photoresist grating with a certain K value is realized in experiments.It is proved that this method has certain instructive effect on the fabricating crossed holographic photoresist grating with a specific profile and microstructure.