Study On Simulation Model Of Atomic Layer Deposition In Advanced Technology Nodes

As the critical dimension of the semiconductor process scales down,more attention has been paid to Atomic Layer Deposition?ALD?techniques because of its high conformability and precise control of the film thickness.However,the increased graphic density and process complexity result in more difficulties in the parameter adjustment.Taking advantage of computers to simulate the process reduces the process adjustment cost and speed up the process,thus is the best way to address the above mentioned challenges.Based on the past relevant researches,this study combines the advantages of important models in order to develop a fast and accurate simulation algorithm for ALD.The development of ALD Process Simulation Program based on MATLAB is able to show the change process of deposition surface profile intuitively,providing a novel way for the modeling of ALD process in advanced nodes.Firstly,this thesis analyzes the basic theory and reaction mechanism of ALD,also it introduces the high-aspect-ratio structure and SAXP process of advanced process nodes;following that it discusses three models simulation system model of deposition:Micro-Surface Process Model,Steady-State Theoretical Model,and Macro-Scale Mode,which with advantages and disadvantages in the number of parameters and the amount of calculation;it also introduces two commonly used algorithms for the the growth system of films:Cellular Automata Method and Geometric Method.Secondly,this thesis establishes the ALD model based Steady-state Process Theory and Modularization method.The calculation and transfer of key variables are accomplished by using the precursor distribution module and the surface reaction coupling module.The model implements the growth module to complete the surface profile evolution.By employing this model to simulate the flat surface growth,we obtains the simulation results of growth rate?0.0738 nm/cycle at 300??.In addition to that,we add the growth direction recognition algorithm so that it can complete the vertical pore structure deposition profile simulation.We use the practical process data to verify the well matching of the model profile and fit the corresponding relationship between temperature and growth rate.Also we made innovation to establish the model of profile deposition of hole structures with inclined corner side walls.Finally,this thesis presents the MATLAB software based program development of the model.Taking the ALD deposition of HfO₂films for example,we use this model to simulate different substrate sizes?radius,depth,aspect ratio?of the hole structure,the simulation results show that the hole bottom growth rate will slow down if given a deep,narrow hole or a hole with a depth-width ratio over 30.We also use this model to simulate the ALD deposition in different reaction environments,the results show that the limit of cycles and the insufficient precursor dose will slow down the growth rate at the bottom of the hole as well.We use this model to simulate the deposition steps of high-aspect-ratio structure and SAXP technology that are widely used in high volume manufacturing,and obtain simulation results that are promising towards future practical applications.