Research On 3-dof Grating Interference Measurement Model Of Mask Table

As the representative of highly ultra-precision machining equipment,the photoengraving machine plays an irreplaceable important role in the field of large-scale integrated circuit manufacturing.As an important core component of the lithography machine,the positioning accuracy in high-speed and multi-degree of freedom directly affects the set accuracy of the lithography machine.In order to realize the high precision motion positioning of the mask,it is necessary to set up accurate multi-degree of freedom decoupling measurement model.We mask more degrees of freedom measurement of laser grating interferometer has gradually replaced the trend of laser interferometer,but the measurement model of the existing research only in the presence of using laser interferometer,and lack of using grating interferometer as feedback element mask table more degrees of freedom measurement model.Therefore,in this paper to mask based on grating interferometer measurement system as the research object,combining with the measurement principle of grating interferometer,the mask set three degrees of freedom of the high speed motion measurement system modeling analysis,establish a grating interferometer readings and mask table location coordinate relations between the mathematical model of perfect mask based on grating interferometer sets of high speed and high precision displacement measurement and positioning theory.The main research work is as follows:First of all,to mask the principle of displacement measurement system and technical indexes for comprehensive analysis,put forward multiple degrees of freedom based on grating interferometer and capacitance sensor measurement,and analysis and design installation and location of sensor on the mask layout.Second,to mask grating interferometer measurement system as the research object,establish in view of the mask grating interferometry system of multiple coordinate system,the use of coordinates,and vector form accurately said mask a measuring system of the relationship between various physical quantities,and the six degree of freedom coupling between conditions were considered in the measurement model.On this basis,the first consideration in an ideal world,in the process of modeling analysis mask table before and after exercise location coordinates and the relationship between the grating interferometer reading,regardless of the installation error of measuring the global model is set up;In consideration of various installation errors,a global model considering installation error is established.Using Solidworks software to simulate the mask measurement system movement,validation does not consider installation error of measuring global model and considering the installation error of measuring global model the correctness of the model,prove that regardless of the installation error of measuring global model is superior to the traditional simple model,meet the demand of mask set the precision of the measurement system;Analyze the influence of each machine constant on the measurement model and obtain the range of each error allowable variation.Finally,in view of the mask measurement system global model for the complicated nonlinear implicit function expression,iterative operation directly affect the real-time measuring system,the numerical calculating method,global model is put forward based on the linearization approximation to solve the numerical method,and using Matlab numerical calculating method for the simulation and analysis,validate feasibility of linearized model numerical calculating method.