Preparation And Characterization Of Novel POSS-PI Hybrid Materials

In recent years, as integrated circuit (IC) dimensions continue todecrease, device performances do not necessarily decrease accordinglybecause of the substantial increases in interconnect delays, cross-talknoise, and power dissipation. The intermetal dielectric layers with lowerdielectric constant are still demanded in order to reduce the signal delaysand electrical power loss in new generation of large scale integratedcircuits. Therefore, the research that has a low dielectric constant andhigh-performance materials was becoming more and more important.Polyimides (PIs) is a very suitable material used in themicroelectronics industry because of their outstanding characteristics,such as excellent tensile strength and modulus, good resistance to organicsolvents, good thermal stability and dielectric property.Polyhedral oligomeric silsesquioxane(POSS) are nanostructureshaving the empirical formula RSiO1.5. It’s0.53nm the size of nano-cage.Therefore POSS having low density, low atomic number, symmetry, andlow molecular polarization characteristics of low dielectric constantmaterial requirements, but also has high mechanical strength and thermalstability.In general, there were two methods reduce the dielectric constant ofthe material: First, reduce material molecular polarizability, and second was increasing the porosity of the material. In order to obtain a lowdielectric material that could be used next-generation LSI, We introducedPOSS with low dielectric properties in polyimide, and by reaction of thebranching obtained larger molecules voids, increased the molecularporosity of material. Thereby obtaining POSS/PI hybrid material withlower dielectric properties. And in order to reduce the thermal expansioncoefficient difference between the material and the metal, phosphoruswas introduced in the POSS/PI organic hybrid materials.Contents of this paper was synthesizing a series of new POSS/PIhybrid materials, and study the effects of phosphorus content andmaterials molecular structure POSS/PI hybrid material properties.This paper was divided into two parts, first was the synthesis of newPOSS/PI hybrid materials, second part, the effects of phosphorus contentand materials molecular structure POSS/PI hybrid material dielectricproperties, thermal and thermal mechanical properties.The first part of the later obtained triphenylphosphine oxide,triphenylphosphine oxide, and the product was subjected to nitration andreduction of two to give the diamine (DAPPO) containing an organicphosphorus; hydrolysis of phenyl trichlorosilane, nitration restore accessto eight phenylamino POSS. And two of the resulting monomer IR, NMRand mass spectrometry to determine its structure, and then copolymerizedby ODA, BPDA and DAPPO, get the same phosphorus content of different chain lengths and phosphorus content of two types gathered inthe same chain length composition, molecular weight and its testing. Theresulting oligomers were copolymerized with POSS step performed toobtain a phosphorus content of different chain lengths and the same typeof phosphorus content in the same chain length novel POSS/PI hybridmaterial.The second part is through the new POSS/PI hybrid materialdielectric properties, thermal and mechanical properties and thermalproperties of the test. Effects of phosphorus respectively and the chainlength of the dielectric properties, thermal and mechanical properties andthermal properties of materials, summarized the law of phosphorus andchain length effects on material properties, which are met by thenext-generation LSI optimal ratio required low dielectric material.Comparative herein by8kinds of synthesized polymers, we foundthat increasing the amount of phosphorus will reduce the dielectricconstant, the lower the thermal expansion coefficient of the material toimprove the thermal stability of the material; same time increasing thechain length of the material will reduce the dielectric constant, thermalexpansion coefficient. Thus found to contain20%organic phosphorusand chain length of20, the material has the most excellent dielectricproperties and thermal expansion properties.