Influence Of Rare Earth Oxides On Structure And Properties Of Low Dielectric Glass Fiber

Low-dielectric electronic glass fiber is the core substrate material of printed circuit boards,which plays a decisive role in improving the electrical insulation performance of large-scale integrated circuit boards and reducing their heat generation and power consumption.It is an indispensable material for advanced electronic components in the fields of aviation,aerospace and military equipment,and supercomputers.In recent years,with the rapid upgrading of electronic products,CCLs are required to have a lower dielectric constant and dielectric loss,thereby speeding up signal transmission,reducing crosstalk and reducing energy consumption.However,the current domestic electronic glass fiber has high dielectric constant and dielectric loss,and can not meet the major needs of supercomputers,5G networks,large aircrafts,high-speed trains and other countries in the electronic information field.Therefore,the research of new low-dielectric glass fibers is very necessary.Based on previous studies,an orthogonal test for Al₂O₃,B₂O₃ and SiO₂ with three-factor and three-level was designed,and all the performances of all samples were tested in this paper.The good main components of glass were obtained by comprehensive analysis.Then,the influences of single doping of rare earth oxides and two co-doping on the basic glass were performed.Based on the dielectric properties and thermal properties of glass,combined with infrared spectroscopy and density analysis,the performance and structure of aluminoborosilicate glasses doped with rare earth oxides were studied.The dielectric constant and loss are reduced,and the dielectric properties of the glass are improved on the basis of the glass fiber that can be drawn and has well thermal stability.The details are as follows:The three main components of glass were determined by orthogonal test,and the performance and structure of each sample were tested and analyzed.The results show that the structure of the glass becomes more dense as the content of Al₂O₃ and SiO₂ increases.When the content of B₂O₃ is 22 mol%,more[BO₃]is formed due to its excessive content and the structure becomes loose.The structural polymerization degree of the glass was better,when the contents of Al₂O₃,B₂O₃ and SiO₂ were 10 mol%,18 mol%and 58 mol%,respectively.The increase of SiO₂ enhances the dielectric properties,while Al₂O₃ is the opposite because more Al₂O₃ is introduced into the interior of the glass[AlO₆].In addition,as the B₂O₃ content increases from 18 mol%to 22 mol%,the dielectric constant and dielectric loss first decrease and then increase.Glass transition temperature?T_g?and transition temperature?T_c?increase with the increase of Al₂O₃,SiO₂ content,but decrease with the increase of B₂O₃ instead of Al₂O₃ or SiO₂.The optimum composition of the glass sample with excellent dielectric properties can be determined as follows:8 mol%Al₂O₃;20 mol%B₂O₃ and 58 mol%SiO₂.The structure and properties of low-dielectric glass fibers doped with La₂O₃,CeO₂ and Y₂O₃,respectively,were investigated.The incorporation of rare earth oxides makes the density of the glass network structure increase first and then decrease.The reason is that rare-earth ions have large field strength and can enter into the network gap to connect negative ion groups as charge compensation when the content is relatively low.The"breaking net"effect dominates glass structure depolymerization as the content of rare earth oxide increases which lead to too much free oxygen is introduced.This leads to the thermal stability of the glass,the dielectric properties with the increase of rare earth oxides to produce the first increase and then reduce.Among this three oxides,the comprehensive dielectric properties of La₂O₃ glass are better than those of the other two glasses.The optimum dielectric constant?4.59?and dielectric loss(0.87×10^-3)were gotten when the content of La₂O₃ is 1.0 mol%and 1.5 mol%,respectively.The addition of three kinds of oxides all increase the density of the glass.But when the content is more than 2.0 mol%,the glass structure becomes loose and the density increases slowly.The effects of two oxides co-doping from Y₂O₃,L₂O₃ and CeO₂ on the structure,thermal properties and dielectric properties of aluminoborosilicate glasses were investigated.In experiments in which La₂O₃ was equimolarly substituted for CeO₂ and Y₂O₃,as the amount of substitution increased,the bridge oxygen bonds in both experimental samples showed a tendency to increase first and then decrease that is due to the strong ion field strength of the cation and the coordination pattern in the glass.When the proportion of the two oxides is around1:1,the dielectric constant,dielectric loss,and Tg of the glass all show extreme values.The better dielectric constant and loss were obtained when the ratio of La₂O₃ to CeO₂ was 1:1,which were 4.53 and 0.78×10^-3,respectively.The density of glass also tends to increase slowly as the amount of substitution increases.In the experiment of replacing Y₂O₃ with CeO₂,the T_g of the glass increased slightly with the increase of the substitution amount,and the change trend of the dielectric properties showed a“V”shape.The dielectric constant and loss were obtained at the optimal ratio of 4.77 and 0.82×10^-3 at the ratio of 2:3 and 1:1 respectively.The density of glass gradually decreases as the amount of substitution increases.