Study On Measurement Techniques In Illumination System Of Deep Ultraviolet Lithography Tools

Deep ultraviolet step-and-scan lithography tool is one of the key equipment for manufacturing of ultra large scale integration circuits.In the process of integration and adjustment of the lithography tool and the illumination system,many measurement techniques and equipments were reserached and developed to provide key data and guide for the assembly and evaluation.In this dissertation,the measurement techniques of illumination system of deep ultraviolet lithography tools were systematically investigated.In the first chapter,the results of previous studies on lithography technology and lithography lighting system were fully reviewed,as well as the related research results and the latest progress.Then,the major parts of this dissertation were briefly introduced.In the second chapter,the imaging optical path of illumination field was analyzed.The relationship between the position of the sca nning slit and the pupil image was established.Major progress and achievements reached are: a)An illumination field parameters measurement technique was proposed.b)A penumbra measurement technique based on pupil image was proposed.The illumination field parameters and penumbra of NA0.82 Kr F and NA0.75 Ar F illumination systems were measured respectively.The feasibility and effectiveness of the two measurement techniques were verified.In the third chapter,the problem of breaking through the resolution limita tion of image sensor and improving the measurement accuracy of illumination pupil was studied and discussed.Major progress and achievements reached are: a)A pupil parameters measurement technique based on sub-pixel subdivision was proposed.b)A new pupil multi parameter evaluation function model was established,and a full field pupil parameters measurement technique based on absolute telecentric center was proposed.The pupil parameters of NA0.82 Kr F and N A0.75 Ar F illumination systems were measured respectively.The results shown that the measurement resolution and repeatability of were improved significantly.In the fourth chapter,the configuration method of free pupil based on micro mirror array was discussed.A new micro mirror array configuration technique based on deconvolution was proposed.The feasibility,efficiency and accuracy of this method were verified by computer simulation.In the fifth chapter,the problem of stress birefringence of optical elements at deep ultraviolet band was discussed.A finite element-based stress birefringence analysis method was proposed.The feasibility and effectiveness of this method were verified by computer simulation.In the sixth chapter,the research work of this dissertation was summarized and prospected.