Theil, J.A., Mirkarimi, L, Fountain, G., Gao, G., Katkar, R.: Recent development in fine pitch wafer-to-wafer hybrid bonding with copper interconnect. In: IEEE IWLPC (2019). https://doi.org/10.23919/IWLPC.2019.8913862 Fan, A., Rahman, A., Reif, R.: Copper wafer bonding. Electrochem. Solid State Lett. 2(10), 534–536 (1999). https://doi.org/10.1149/1.1390894 Copper: Proceedings of the International Conference Copper '06 by Jean-Marie Welter (ed). Wiley-VCH, 2006. Latest issues and trends summarized in papers from a 2006 international conference.

Chen, K.N., Fan, A., Tan, C.S., Reif, R.: Temperature and duration effects on microstructure evolution during copper wafer bonding. J. Electron. Mater. 32(12), 1371–1374 (2003). https://doi.org/10.1007/s11664-003-0103-5Park, J., Kim, J., Park, Y.: Effects of wet treatment conditions and pattern densities on interfacial bonding characteristics of Cu–Cu direct bonds. Jpn. J. Appl. Phys. 53, 05HB07 (2014). https://doi.org/10.7567/JJAP.53.05HB07 The gates of the Temple of Jerusalem used Corinthian bronze treated with depletion gilding. [ clarification needed] [ citation needed] The process was most prevalent in Alexandria, where alchemy is thought to have begun. [111] In ancient India, copper was used in the holistic medical science Ayurveda for surgical instruments and other medical equipment. Ancient Egyptians ( ~2400BC) used copper for sterilizing wounds and drinking water, and later to treat headaches, burns, and itching. [ citation needed] Modern Acid mine drainage affecting the stream running from the disused Parys Mountain copper mines 18th-century copper kettle from Norway made from Swedish copper

Park, H., Seo, H., Kim, S.E.: Anti-oxidant copper layer by remote mode N 2 plasma for low temperature copper–copper bonding. Sci. Rep. 10, 21720 (2020). https://doi.org/10.1038/s41598-020-78396-x

Characteristics Physical A copper disc (99.95% pure) made by continuous casting; etched to reveal crystallites Copper just above its melting point keeps its pink luster color when enough light outshines the orange incandescence color.

Li, G., Kang, Q., Niu, F., Wang, C.: Recent progress on bumpless Cu/SiO 2 hybrid bonding for 3D heterogeneous integration. Microelectron. Int. (2022). https://doi.org/10.1108/MI-07-2022-0121 The electron configuration of sodium is 1s 22s 22p 63s 1; it contains one electron in its valence shell. In the solid-state, metallic sodium features an array of Na + ions that are surrounded by a sea of 3s electrons. However, it would be incorrect to think of metallic sodium as an ion since the sea of electrons is shared by all the sodium cations, quenching the positive charge. while identified world resources total 2.1 billion tonnes. (Source: U.S. Geological Survey, Mineral Commodity Summaries, January 2022.) Kim, S., Nam, Y., Kim, S.E.: Effects of forming gas plasma treatment on low-temperature Cu–Cu direct bonding. Jpn. J. Appl. Phys. 55, 06JC02 (2016). https://doi.org/10.7567/JJAP.55.06JC02During the rise in demand for copper for the Age of Electricity, from the 1880s until the Great Depression of the 1930s, the United States produced one third to half the world's newly mined copper. [116] Major districts included the Keweenaw district of northern Michigan, primarily native copper deposits, which was eclipsed by the vast sulphide deposits of Butte, Montana, in the late 1880s, which itself was eclipsed by porphyry deposits of the Southwest United States, especially at Bingham Canyon, Utah, and Morenci, Arizona. Introduction of open pit steam shovel mining and innovations in smelting, refining, flotation concentration and other processing steps led to mass production. Early in the twentieth century, Arizona ranked first, followed by Montana, then Utah and Michigan. [117] Weng, M.W., Mao, S.Y., Liu, D., Hu, H.W., Chen, K.N.: Asymmetric low temperature cu-polymer hybrid bonding with Au passivation layer. In: VLSI-TSA, pp. 2021–2022 (2021). https://doi.org/10.1109/VLSI-TSA51926.2021.9440101 Copper is one of the few metals that can occur in nature in a directly usable metallic form ( native metals). This led to very early human use in several regions, from c. 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, c. 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create bronze, c. 3500 BC. [6] Kim, S., Kang, P., Kim, T., Lee, K., Jang, J., Moon, K., Na, H., Hyun, S., Hwang, K.: Cu microstructure of high density Cu hybrid bonding interconnection. In: IEEE 69th ECTC, pp. 636–641 (2019). https://doi.org/10.1109/ECTC.2019.00101 Hong, Z.J., Liu, D., Hu, H.W., Cho, C.I., Weng, M.W., Liu, J.H., Chen, K.N.: Investigation of bonding mechanism for low-temperature Cu–Cu bonding with passivation layer. Appl. Surf. Sci. 592, 1–7 (2022). https://doi.org/10.1016/j.apsusc.2022.153243

Wang, Q., Zhang, S., Lin, T., Zhang, P., He, P., Paik, K.W.: Highly mechanical and high-temperature properties of Cu–Cu joints using citrate-coated nanosized Ag paste in air. Progress Nat. Sci. Mater. Int. 31(1), 129–140 (2021). https://doi.org/10.1016/j.pnsc.2020.12.004 Despite competition from other materials, copper remains the preferred electrical conductor in nearly all categories of electrical wiring except overhead electric power t Copper has been in use for at least 10,000 years, but more than 95% of all copper ever mined and smelted has been extracted since 1900. [31] As with many natural resources, the total amount of copper on Earth is vast, with around 10 14 tons in the top kilometer of Earth's crust, which is about 5million years' worth at the current rate of extraction. However, only a tiny fraction of these reserves is economically viable with present-day prices and technologies. Estimates of copper reserves available for mining vary from 25 to 60 years, depending on core assumptions such as the growth rate. [32] Recycling is a major source of copper in the modern world. [31] Because of these and other factors, the future of copper production and supply is the subject of much debate, including the concept of peak copper, analogous to peak oil. [ citation needed] If you work through the same argument above for sodium with magnesium, you end up with stronger bonds and hence a higher melting point. the Iceman, a male dated from 3300 to 3200BC, was found with an axe with a copper head 99.7% pure; high levels of arsenic in his hair suggest an involvement in copper smelting. [91] Experience with copper has assisted the development of other metals; in particular, copper smelting led to the discovery of iron smelting. [91] Copper artifacts from the Old Copper Complex of North America, which may have existed from approximately 9500–5400 years before presentThe Coming Copper Peak by Richard A. Kerr. Science, February 14, 2014. We've heard a lot about peak oil, but how much do you know about "peak copper"? So not only will there be a greater number of delocalized electrons in magnesium, but there will also be a greater attraction for them from the magnesium nuclei. Magnesium atoms also have a slightly smaller radius than sodium atoms, and so the delocalized electrons are closer to the nuclei. Each magnesium atom also has twelve near neighbors rather than sodium's eight. Both of these factors increase the strength of the bond still further. Beyne, E., Kim, S., Peng, L., Heylen, N., Messemaeker, J. De, Okudur, O.O., Phommahaxay, A., Kim, T., Stucchi, M., Velenis, D., Miller, A., Beyer, G.: Scalable , sub 2 μm Pitch, Cu/SiCN to Cu/SiCN hybrid wafer-to-wafer bonding technology. In: IEEE IEDM, pp. 729–732 (2017). https://doi.org/10.1109/IEDM.2017.8268486