Low Damage Cryogenic Etching of Porous Organosilicate Low-k Materials Using SF6/O2/SiF4

Zhang, Liping; Ljazouli, Rami; Lefaucheux, Philippe; Tillocher, Thomas; Dussart, Rémi; Mankelevich, Yu. A.; Marneffe, Jean‐François de; Gendt, Stefan De; Baklanov, Mikhaı̈l R.

doi:10.1149/2.001306jss

Cited by 35 publications

(20 citation statements)

References 43 publications

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“…176,186 Condensation of the etch products provides very low degradation of porous OSG and the lowest integrated k-value was achieved by using this approach. 238 In the blanked studies, 176,177,178,179 OSG low-k damage in both SF6 and SF4/O2 mixture is significantly reduced with decreasing temperature. In the ref.…”

Section: Iii4 Vuv Induced Effects In Etch Plasmamentioning

confidence: 97%

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Baklanov

Jousseaume

Рахимова

et al. 2019

Applied Physics Reviews

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This paper presents an in-depth overview of the application and impact of UV/VUV light in advanced interconnect technology. UV light application in BEOL historically was mainly motivated by the need to remove organic porogen and generate porosity in organosilicate (OSG) low-k films. Porosity lowered the film's dielectric constant, k, which enables one to reduce the interconnect wiring capacitance contribution to the RC signal delay in integrated circuits. The UV-based low-k film curing (λ > 200 nm) proved superior to thermal annealing and electron beam curing. UV and VUV light also play a significant role in plasma-induced damage to pSiCOH. VUV light with λ < 190–200 nm is able to break Si-CH3 bonds and to make low-k materials hydrophilic. The following moisture adsorption degrades the low-k properties and reliability. This fact motivated research into the mechanisms of UV/VUV photon interactions in pSiCOH films and in other materials used in BEOL nanofabrication. Today, the mechanisms of UV/VUV photon interactions with pSiCOH and other films used in interconnect fabrication are fairly well understood after nearly two decades of research. This understanding has allowed engineers to both control the damaging effects of photons and utilize the UV light for material engineering and nanofabrication processes. Some UV-based technological solutions, such as low-k curing and UV-induced stress engineering, have already been widely adopted for high volume manufacturing. Nevertheless, the challenges in nanoscaling technology may promote more widespread adoption of photon-assisted processing. We hope that fundamental insights and prospected applications described in this article will help the reader to find the optimal way in this wide and rapidly developing technology area.

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Section: Iii4 Vuv Induced Effects In Etch Plasmamentioning

confidence: 97%

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Baklanov

Jousseaume

Рахимова

et al. 2019

Applied Physics Reviews

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“…32,91 It is well known that chemical processes in plasma etching processes follow an Arrhenius law where the reaction rate is proportional to A exp[-E A /RT]. Therefore, decreasing the reaction temperature to cryogenic levels also lowers the reaction rate constant of the different reactive species in the plasma.…”

Section: Impact Of Etch Temperature (Cryo-etch)mentioning

confidence: 99%

Toward Successful Integration of Porous Low-k Materials: Strategies Addressing Plasma Damage

Lionti

Volksen

Magbitang

et al. 2014

ECS J. Solid State Sci. Technol.

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The increasing sensitivity of porous low dielectric constant materials to process damage constitutes a major roadblock to their implementation in back-end-of-the-line (BEOL) wiring structures for advanced technology nodes. In the early 2000s and in anticipation to future low-k related integration challenges, the semiconductor industry started to investigate the possibility to repair or prevent this damage. It is remarkable that the most disruptive solutions proposed today are inspired from the work initiated more than 10 years ago. In this review we first describe the accepted mechanisms for plasma damage, followed by a quick summary of the methods used to quantify its extent on both blanket films and patterned structures. We then report on the past and current strategies developed to mitigate the plasma damage of porous, low-k materials during damascene integration processes.

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“…Recent results from Zhang et al 45 show that carbon depletion can be significantly reduced at cryogenic temperature due to etch by-product condensation in pores, which blocks active radical diffusion.…”

Section: Reliability After Integrationmentioning

confidence: 99%

Electrical Reliability Challenges of Advanced Low-k Dielectrics

Baklanov

et al. 2014

ECS J. Solid State Sci. Technol.

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We review the latest studies that address the fundamental understanding of low-k dielectric electrical properties and reliability. We focus on the results discussing the nature of process induced defects, leakage currents and breakdown behavior, as they are important factors to reveal material modification and damage. Issues related to the use of porogen based PECVD techniques during dielectric deposition are discussed, where we focus on the selection of matrix and porogen precursors and on the improvements related to post-deposition treatments. During damascene integration, low-k dielectrics are subjected to several processes that induce material damage, where we review recent learning about plasma exposure, barrier deposition and chemical mechanical polishing. In order to have a successful implementation of advanced ultralow-k films in back-end-of-line interconnects, we argue that more research efforts are needed with respect to its material development, integration and reliability and make some proposals for future work. The development and integration of reliable low-k materials is a key challenge for next generation interconnect technologies. Driven by the requirement of performance increase, highly porous low-k dielectrics are incorporated in deeply scaled back-end-of-line (BEOL) interconnects. In general, there are three important concerns during the study of low-k dielectric electrical properties and reliability: a) the k-value of the dielectric after integration should maintain relatively unchanged, b) the leakage current of the dielectric between metal lines should be low, and c) the time dependent dielectric breakdown (TDDB) failure time of the integrated BEOL structure at operating conditions should meet its specifications. 1Porous SiOCH low-k dielectrics deposited by plasma enhanced chemical vapor deposition (PECVD) techniques are the dominant choice for k>2.2 film depositions and are also potential candidates for ultralow-k (k<2.2) dielectric applications.2 In the past years, significant efforts have been spent to understand their material properties and integration challenges. The bond structures of low-k dielectrics is complex due to the non-equilibrium nature of the PECVD technique.

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Low Damage Cryogenic Etching of Porous Organosilicate Low-k Materials Using SF₆/O₂/SiF₄

Cited by 35 publications

References 43 publications

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Toward Successful Integration of Porous Low-k Materials: Strategies Addressing Plasma Damage

Electrical Reliability Challenges of Advanced Low-k Dielectrics

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