Gap Detection And Leveling Technology For Plasmonic Super-resolution Lithography

With the rapid development of the semiconductor industry,the core devices of intelligent sensing,artificial intelligence,communications networks,e-commerce,and other fields tend to miniaturization,which put higher demands on the manufacturing process technology.Conventional lithography is limited by the diffraction limit and the highest resolution can only reach half of the wavelength of the light source.Recently,surface plasmonic(SP)super-resolution lithography has become an emerging technology to break the "diffraction limit" for the conventional lithography.However,the short working distance of the SP brings obstacles to the application of this potential technology and results in the problems such as the contamination and damage of the mask and patterns.The proximity SP lithography technology is proposed to solve these problems,but the micro-nanometer-level gap detection and leveling technology become the key problem in this field.In this paper,the study of gap detection and leveling technology for surface plasmon super-resolution lithography is carried out under the support of "super-resolution lithography equipment development" project.The main works are listed as follows:Firstly,the advantages of SP super-resolution lithography technology and the significance are analyzed by comparing different types of next-generation lithography techniques.Then,the interferometric spatial phase imaging(ISPI)gap detection technique and the three-point leveling method for SP super-resolution lithography are proposed on the basis of study and analysis of the existing gap detection and leveling technology.Secondly,according to ISPI gap detection principle and lithography leveling technology,the gap detection and leveling device for the SP super-resolution lithography system is designed,built up and applied to the SP super-resolution lithography system.The SP super-resolution lithography system mainly consists of the light source module,the gap detection module,the lithography lens module,the alignment module and the substrate stage module.According to the three-point leveling algorithm,the corresponding active leveling structure is designed.The control program for the super-resolution lithography system is developed with LabVIEW graphical programming language,which provides a good human-computer interaction interface.Finally,the mask with ISPI gap detection pattern area is designed and fabricated.The ISPI gap detection pattern consists of angle correction grating mark and gap detection grating mark.The incident optical path is corrected through the debugging system.On-line testing of the gap detection experiment is conducted using the dominant frequency analysis method,and the detection accuracy up to 0.1?m in theory.Then,the stability of the system is tested.And the automatic leveling experiment gives a rough leveling accuracy of 1?m.