Hermeticity test of low-melting point sealing glass and analysis of encapsulation failure

With the rapid development of modern microelectronics and optoelectronics technology, a novel potential sealing method, Laser-assisted glass frit bonding (hereafter referred to as Laser bonding), are proposed for encapsulating electronic, optical, and miniature micro-mechanical devices that require a hermetic seal with long-term stability. In this work, we fabricated two kinds of glass pastes which were bismuthate glass powder and phosphate vanadate glass powder mixed in the same organic component solvent, respectively. Then two pairs of blank glass substrate go through screen printing, pre-sintering and laser bonding with the glass pastes as two group sample. Next, we conducted a series of experiments to learn hermeticity of these two different kinds of sealing glass system. The tests were performed by dipping samples in a low-tension liquid-ethanol-colored with a dye. We have found that bismuthate glass frit cord showed strong steady erosion resistance and phosphate vanadate glass joining begin to breakdown in 12h. Hence, we analyzed the mechanism of encapsulation failure by Raman spectroscopy. We inferred that the V
³⁺
and P
⁵⁺
in the surface of glass dissolved in H
₂
O while glass network cracked and defects came out. Over time, the depth of the erosion is more and more deep. In the end, encapsulation failed.