Fast Atom Beam- and Vacuum-Ultraviolet-Activated Sites for Low-Temperature Hybrid Integration.

The evolution of surface chemical structures of polyimide induced by Ar fast atom beam (Ar-FAB) bombardment and vacuum ultraviolet (VUV) irradiation was investigated using X-ray photoelectron spectroscopy (XPS) to clarify the activated sites for low-temperature hybrid bonding. These sites in molecular chains are considered corresponding to the bonding sites. They affect interfacial properties. Therefore, such analyses are necessary to optimize the processing parameters in different surface-modification methods. The XPS results demonstrated that Ar-FAB physical bombardment transformed the polyimide surface into benzene-dominant structures, whereas the effect of VUV irradiation was located at side chain groups such as ether and carbonyl, resulting in much longer molecular fragments (i.e., less matrix damage). Moreover, the calculated thickness of the VUV-induced modification layer grew to around 0.6 nm at its maximum.

Organic-Inorganic Solid-State Hybridization with High-Strength and Anti-Hydrolysis Interface.

Organic-inorganic material hybridization at the solid-state level is indispensable for the integration of IoT applications, but still remains a challenging issue. Existing bonding strategies in the field of electronic packaging tend to employ vacuum or ultrahigh temperature; however, these can cause process complications and material deterioration. Here we report an easy-to-tune method to achieve hybrid bonding at the solid-state level and under the ambient atmosphere. Vacuum-ultraviolet (VUV)-induced reorganization with ethanol was used to develop hydroxyl-carrying alkyl chains through coordinatively-bonded carboxylate onto aluminum, whereas numerous hydroxyl-carrying alkyls were created on polyimide. The triggering of dehydration through these hydroxyls by merely heating at 150 °C for a few minutes produced robust organic-inorganic reticulated complexes within the aluminum/polyimide interface. The as-bonded aluminum/polyimide interface possessed an superior fracture energy of (2.40 ± 0.36) × 103 (J/m2) compared with aluminum and polyimide matrices themselves, which was mainly attributed to crack deflection due to the nano-grains of inorganic-organic reticulated complexes. The interfacial adhesion was successfully kept after humidity test, which was contributed by those anti-hydrolytic carboxylates. To the best of our knowledge, for the first time organic-inorganic bonding at the solid-state level was achieved using the ethanol-assisted VUV (E-VUV) process, a strategy which should be applicable to a diversity of plastics and metals with native oxides.

Novel Self-shrinking Mask for Sub-3 nm Pattern Fabrication.

It is very difficult to realize sub-3 nm patterns using conventional lithography for next-generation high-performance nanosensing, photonic, and computing devices. Here we propose a completely original and novel concept, termed self-shrinking dielectric mask (SDM), to fabricate sub-3 nm patterns. Instead of focusing the electron and ion beams or light to an extreme scale, the SDM method relies on a hard dielectric mask which shrinks the critical dimension of nanopatterns during the ion irradiation. Based on the SDM method, a linewidth as low as 2.1 nm was achieved along with a high aspect ratio in the sub-10 nm scale. In addition, numerous patterns with assorted shapes can be fabricated simultaneously using the SDM technique, exhibiting a much higher throughput than conventional ion beam lithography. Therefore, the SDM method can be widely applied in the fields which need extreme nanoscale fabrication.