This work investigates the integration of very thin sputtered Ta and reactively sputtered TaN barriers with Cu and a low-dielectricconstant (low-K) layer of poly(arylene ether) (PAE-2). It is found that Cu readily penetrates into PAE-2 and degrades its dielectric strength in metal-insulator semiconductor capacitors of Cu/PAE-2/Si structure at temperatures as low as 200ЊC. Very thin Ta and TaN films of 25 nm thickness sandwiched between Cu and the low-K dielectric served as effective barriers during a 30 min thermal annealing at temperatures up to 400 and 450ЊC, respectively. We propose a failure mechanism of outgassing induced gaseous stress of PAE-2 under the Ta film to explain its premature barrier degradation. The TaN barrier did not suffer from this gaseous stress problem because of its stronger adhesion to PAE-2 than that of Ta to PAE-2, leading to a better long-term reliability.
This work investigates the dielectric and barrier properties of two species of organic aromatic low dielectric constant ͑low-k͒ polymers, namely, FLARE and SiLK. Experimental results indicate that both of the low-k polymers exhibit acceptable thermal stability with respect to a thermal annealing at 400°C for 8 h in an N 2 ambient. Moreover, they show a good dielectric barrier property against Cu penetration under bias-temperature stressing ͑BTS͒ at 150°C with an applied effective field of 0.8 MV/cm. Nevertheless, an anomalous instability of the capacitance-voltage curve was observed for the first time under BTS. This finding is explained by the proposed model of stress induced dielectric polarization charges within these organic aromatic polymers. The polarization instability may seriously degrade the long term reliability of circuit operations.Interconnect wire parasitics ͑wire resistance R and intra/interlevel capacitance C͒ at 0.18 m begins to dominate not only the overall device delay but also the packing density, reliability, and manufacturing cost of integrated circuits ͑ICs͒. 1 The RC time delay must be reduced by using new materials to alleviate the problem of achieving high performance ultralarge-scale integrated ͑ULSI͒ circuits without compromising the requirements of driving speed, crosstalk tolerance, and dynamic power dissipation imposed by the small feature sizes. 2 The substitution of Cu for Al and its alloys leads to lower electrical resistivity and superior electro/stressmigration resistance, as compared to the conventional Al-based metallization scheme. However, dielectrics with low dielectric constants ͑low-k͒ must be used to reduce the parasitic capacitance, which is dominated by the interline capacitance component in long parallel lines. 3 Therefore, the process integration of Cu-based metallization and low-k dielectrics has been eagerly pursued in the prevalent Cu dual damascene architecture.Although Cu interconnects originally offered the promise of 30% faster devices with fewer metal levels and a lower cost of production, attaining high device yields on chips with Cu interconnects remains the greatest challenge, making low-k the key enabler for high performance. 4 Low-k (kϽ3.0) dielectrics are currently being actively developed and present substantial challenges on both organic ͑carbon-based͒ and inorganic (SiO 2 -based͒ materials using either spin-on ͑SO͒ or chemically vapor deposited techniques. Among various organic polymers, such as fluorinated amorphous carbon, fluorinated polyimides, poly͑arylene ether͒, and benzocyclobutene, aromatic polyether polymers have recently attracted much attention. 1,4,5 These polymers are known to possess a better thermal and mechanical stability than aliphatic polymers, resulting in improved compositional, dimensional, and topographical integrity over continuous high temperature thermal cycles. Moreover, although the integration issues concerning Cu and various low-k dielectrics have been widely addressed, most of those investigations focused on the pure...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.