The Properties Research Of Low-k Borate And Niobate Glass

Low dielectric glass is an important and widely used electronic material. It has low dielectric constant and small dielectric loss, excellent thermal performance and chemical resistance, good mechanical properties, mainly used in capacitors and supporting layer of electric circuit components. Compared with organic dielectric materials, dielectric glass has a wider range use in IC industry, mobile communications, satellite communications and other fields of optical communication and optoelectronic materials for its better properties, such as smaller coefficient of thermal expansion, better thermotolerance and longer service life. However, with the high-speed development of IC, RF connector and microwave elements, the traditional low-dielectric glass can’t meet the demand of those industries, therefore, develop new dielectric glass has become the research hot topic.Based on former researchers’work, three kinds glass systems were studied in this paper: silicate glass with high content B2O3system, rare earth metal oxide Ta2Os doping niobate glass system, the above two kinds of glass powder mixed in a certain ratio system. The thermal behavior, dielectric properties and the interaction and transformation among the groups of the glasses were studied.High content of B2O3doping in borosilicate glass:The DTA results show that it is difficult for the borosilicate glasses with high content B2O3to crystallize, because B2O3take part in the construction of glass network and its bond is so strong that it is hard to break. The IR analysis indicate that following the content of B2O3increasing,[BO3] and [BO4] both increased sharply and the main products were [BO3]. Both relative permittivity and dielectric wastage appeared minimal value at1MHz at room temperature (5.19for permittivity;3.584×10-4for dielectric loss), the excess content of B2O3would be counterproductive. The thermal expansion coefficient presented an S type variation possibly because the boron anomaly occurred. The transition temperature, softening temperature and high temperature viscosity decreased with the doping of B2O3.Rare earth Ta2O5doping niobate glass system:The IR results show that Ta5+did not participate in the formation of the glass network, it declined the degree of polymerization of glass network. The DTA results that the curve of glass sample without Ta2O5only has one widely crystallization peak, after adulterating Ta2O5, this peak divided into two sharp crystallization peak. From the XRD results, it could be got that the crystal phase at low temperature were NaNbO3、NaTaO3、 Ba5.5Nb2O10.5、 Na2Ta6Si2O15, the high temperature crystal phase wereNaNbO3、 NaTaO3、 Ba2NaTa5O15、 BaNb3.60io. The SEMpictures indicate that the measure of the high temperature crystal were bigger than low temperature crystal phase’s. The addition of Ta2Os could decline the dielectric constant and dielectric loss in a limited range. When the content of Ta2O5reached3%mole, permittivity and dielectric loss respectively had their min value10.67and3.63X10"3. After the crystallization, the high temperature crystal phase has bigger relative permittivity and dielectric loss than the low temperature crystal phase’s. The transition temperature and softening temperature decreased with the doping of Ta2O5. The thermal expansion coefficient presented an N type change, because of the combined action of the network structure was loosen and non-bridging oxygens content increased.Mixing glass system:The dielectric test results show that the dielectric constant of mixing glass system was much smaller than the above two glass system of which the min value is4.18because of the formation of large numbers of pore. However, the pores lead to the increase of dielectric loss.