Scalable, sub 2μm pitch, Cu/SiCN to Cu/SiCN hybrid wafer-to-wafer bonding technology
This paper presents a novel approach to face-to-face wafer-to-wafer (W2W) bonding using SiCN-to-SiCN dielectric bonding, in combination with direct Cu-Cu bonding using Cu pads of unequal size and surface topography for the top and bottom wafers. The use of SiCN dielectrics allows to obtain a high W2W bonding energy (> 2 J/m2) at low annealing temperature (250 °C). Excellent Cu-Cu bonding is obtained after annealing at 350 °C. A novel CMP process, resulting in a slightly protruding Cu top pad and a slightly recessed Cu bottom pad, is introduced. The difference in pad sizes, allows for the necessary W2W overlay bonding tolerances. Excellent resistivity and yield results are obtained across bonded 300 mm Si wafers for scaled 360 nm top pads bonded to 720 nm bottom pads at 1.44 μm pitch (25% bottom Cu density). Feasibility of smaller pitches has been demonstrated by successfully bonding 180 nm top pads to 540 nm bottom pads at 0.72 μm pitch.
The 3-D Interconnect Technology Landscape
This overview article sheds light into the diverse notions and terms associated with 3-D circuits. It categorizes and classifies the various technologies/techniques and helps the experienced researcher as well as a newcomer to find an orientation in the complex 3-D landscape.
Single step formation of biocompatible bimetallic alloy nanoparticles of gold and silver using isonicotinylhydrazide.
Manufacturing nanoparticles with controlled physicochemical properties using environment-friendly routes have potential to open new prospects for a variety of applications. Accordingly, several approaches have been established for manufacturing metal nanoparticles. Many of these approaches entail the use of hazardous chemicals and could be toxic to the environment, and cannot be used readily for biomedical applications. In the present work, we report a single step bio-friendly approach to formulate gold (Au), silver (Ag), and Au-Ag alloy nanoparticles with desired surface corona and composition using isonicotinylhydrazide (INH) as a reducing agent. INH also functioned as a stabilizing agent by enabling a surface corona around the nanoparticles. Remarkably, within a single step INH could also provide a handle in regulating the composition of Au and Ag in bimetallic systems without any additional chemical modification. The physicochemical and surface properties of the different nanoparticles thus obtained have been examined by analytical, spectroscopic and microscopic techniques. Cell cytotoxicity (release of lactate dehydrogenase), cell viability and intracellular reactive oxygen species (ROS) assays confirmed that the Au, Ag, and Au-Ag bimetallic nanoparticles prepared with INH are biocompatible. Finally, the presence of organic surface corona of INH on the nanoparticles was found to impart nanozyme activity and antimycobacterial sensitivity to the nanoparticles.