Low-temperature direct bonding of Si and quartz glass using the APTES modification

Low-temperature direct bonding is an attractive technique for joining mirror polished dissimilar materials with large mismatch in the coefficient of thermal expansion or/and lattice constant. In this paper, we proposed a method for the direct bonding of Si and quartz glass using the 3-aminopropyltriethoxysilane (APTES) modification. Strong bonding strength which was equal to or stronger than the fracture strength of the quartz glass substrate has been achieved after the Si/quartz glass pre-bonded pair was annealed at 150 degrees C. Based on the analyses of the wettability and surface chemical states, grafting of APTES and substitution of ethoxy groups have been studied in detail. Additionally, the tight and nanoscale bonding interface observed by scanning electron microscopy and transmission electron microscopy also ensured the excellent sealability, as well as, facilitated the device miniaturization.