Study On The Damage Behavior Of Ceramic Materials In Plasma Environment

In semiconductor manufacturing,the high-energy and fluorine-containing plasma will erode the etching machine chamber and the components inside chamber,which will shorten the service life of the components.Meanwhile,the non-volatile fluoride product will be deposited on the surface of the components and fall off into impurity particles finally,which would affect the cleanliness of the chamber.With the decrease of the minimum characteristic size of the chip and the increase of the energy of halogen plasma,it is more important to have better resistance to plasma for the chamber and the components inside chamber.In this paper,Y₂O₃ matrix and YAG matrix composite materials were prepared by hot pressing.The mechanical properties and plasma resistance of the various ceramic materials were compared and analyzed in terms of their composition and microstructure.By simulating the chemical etching in plasma etching process with the hydrofluoric acid corrosion and comparing the etching morphology and corrosion morphology of various ceramic materials,the plasma etching mechanism of ceramic materials was analyzed.Firstly,through adding proper amount of Al₂O₃ or Zr O₂ respectively,Y₂O₃ matrix and YAG matrix composite materials were prepared by hot pressing with high purity nano-Y₂O₃ powder and imported YAG powder as matrix materials.It could promote particle rearrangementhe by the viscosity flow and plastic deformation at high temperature and high pressure and the mixing of two kinds of powders with different particle size could fill the pores,which were both helpful to the densification of ceramic materials.Compared with the high purity Y₂O₃,the mechanical properties of 50YZ and YZA were improved significantly.Meanwhile,The mechanical properties of YAG and YAGA were excellent but lower than the high purity Al₂O₃.Then,the plasma etching test was carried out in ICP etching machine with mixed gas C₄F₈/CHF₃/Ar.By comparing and analyzing the etched surface morphology of Y₂O₃matrix and YAG matrix composite materials,it suggestteded that the plasma resistance of purity Y₂O₃ was obviously better than purity Al₂O₃,becuase the bond energy of Y-O is higher than Al-O and yttrium fluoride is non-volatile,and 50YZ and YZA containing Y₂O₃ exhibited better plasma resistance as well.YAG was easily etched in fluorinated plasma because of its high porosity and the content of metal impurity.Furthermore,the etched trace of YAGA was very obvious,because there were a lot of defects in the grain boundary of polycrystalline ceramics,which could be preferentially etched in the process of plasma etching.Finally,the plasma etching mechanism of ceramic materials was disscussed by comparing the surface morphology of plasma etching and hydrofluoric acid etching.There was much difference between the etched and corroded surface morphology.The etched surface is uneven by ion bombardment in plasma etching,but the corroded surface is relatively flat by the dissolved chemical corrosion in hydrofluoric acid etching.The etching of ceramic materials was mainly caused by ion sputtering in the plasma environment,so the plasma resistance of ceramic materials was influenced by the interatomic bond energy.And there was not obvious correlation between the palsma resistance and the mechanical properties for ceramic materials.In addition,other factors also affected the plasma resistance of ceramic materials in plasma environment,such as the composition,metal impurity content,porosity,grain boundary phase and so on.