Study on addition of neodymium oxide to boron-based and phosphorous-based vanadium-iron glass systems and these applications to laser-assist sealing technology for LED devices

  • 林 志昀

Student thesis: Doctoral Thesis


Glass frit encapsulation for laser-base sealing of the complex interiors results challenges for the electronics manufacturing process The heating modes have been studies and developed over past decades The traditional modes especially oven and furnace are widely used to manufacturing While the sealing by furnace reports to the worst in electrical characteristics and illuminating the performance of by laser source presents the comparable to commercialization The conventional frit packaging method relies on elevating thermal process by furnace where the package is heated to reach the required temperature hence limiting the use of temperature-sensitive materials such as LED or OLED and also generating unpredictable problems in different packaging processes or multi-stage sealing products In this thesis the benefits of combining novel laser-assist hermetical sealing and low temperature glass frit packaging are demonstrated and the technique offers a suitable and feasible solution The advantages of neodymium oxide (Nd2O3) are mainly used as a color coder for glass and ceramics raw materials for metal tantalum and ferromagnetic neodymium-iron-boron materials Furthermore this is able to improve the hermeticity and corrosion resistance of the entire material In addition there is a certain extent of influence on the performance of mechanical properties and wear resistance Therefore it is included in this experiment and its characteristics in the glass systems are discussed In addition the study also includes to the rare earth Nd2O3 doped glass systems namely B2O3–V2O5–Fe2O3 (BVF) and P2O5–V2O5–Fe2O3 (PVF) are jointly evaluated for physical and optical properties Quaternary oxide glasses Nd2O3–B2O3–V2O5–Fe2O3 and Nd2O3–P2O5–V2O5–Fe2O3 are prepared by conventional melt quench technique and Nd2O3 plays as glass modifier influencing on the conversion between of BO3 and BO4 PO5 and PO4 and of VO5 to VO4 along with the NBO This objective is to seek for a lower melting temperature glass frit and appropriate adhesive material As knew the rare earths have specific wavelength of absorption supplying to the selection of laser utilized this trait to fierce vibration and then heating up rapidly in the very short period Then follows the density molar weight etc report to the meaningful relationship to refractive index With the increase in Nd2O3 content refractive index and optical basicity show upward trends; by contrast optical energy band gap and metallization criterion represent to reverse correlation Meanwhile the optical energy band gap is often used to illustrate the interaction between electrons and holes by absorption of wavelength and determine its color and conductivity especially in semiconductor materials and PVF is roughly twofold the optical energy band gap of BVF Laser packaging technology has gradually been applied to high-end electronic sealing requirements In the traditional high-temperature packaging process the life of electronic components is considerably damaged The localized heating method of laser avoids this damage by global heating and meanwhile significantly reduces component loss Due to the addition of Nd2O3 there is a clear absorption peak at 808 nm analyzed by UV-Vis The wavelength of 808 nm is as the dominant wavelength and analyzes and subsequently compares the surface microstructure and electrical properties after being sealed by laser-assist heating with a commercially epoxy resin However high resistance and leakage have occurred in high-temperature furnace packages due to the fact that high-temperature melting (temperature of about 680°C) results in the damage of LED device (typically the adorable maximum temperature of LED is below 400°C) According to previous experiment the minimum melting point of both glass systems (BVF & PVF) is between 650°C and 690°C which is much higher Without adding lead and bismuth materials lowering the glass melting point is another project in the future In stark contrast localized laser heating method can minimize the damage by thermal accumulation The advantage of laser glass frits bonding is the non-stringent requirements of high bonding strength and low stress at the juncture interface good process yield repeatability air-tight sealing and flatness of the surface to be bonded These advantages are combined with local heating and controllable processes based on the low melting glass frit of the laser process described herein As can be seen commercialized product epoxy resins cannot provide well sealing capability under long-term humid conditions and indirectly demonstrate that plasticized materials cannot affordable to withstand light and moisture and are also unsuitable sealing applications for outdoor and harshness products
Date of Award2018 May 23
Original languageEnglish
SupervisorYun-Hwei Shen (Supervisor)

Cite this