Plasma Processing of Low‐<i>k</i>Dielectrics

Shi, Hua‐Tian; Shamiryan, Denis; Marneffe, Jean‐François de; Huang, Huai; Ho, Paul S.; Baklanov, Mikhaı̈l R.

doi:10.1002/9781119963677.ch3

Cited by 12 publications

(11 citation statements)

References 109 publications

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“…Shi et al, provides a brief review of low- repair by thermal silylation. 375 Silane coupling agents were found to preferentially react on the surface of the damaged SiCOH/pSiCOH leaving most of the damaged layer unrepaired. The silane coupling agents could not diffuse into nonporous SiCOH films, and pSiCOH films are designed to minimize the average pore size to <2.5nm and pore connectivity, which reduce the diffusivity.…”

Section: V11 Uv-assisted Low- Damage Repairmentioning

confidence: 96%

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: V11 Uv-assisted Low- Damage Repairmentioning

confidence: 96%

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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“…6 Ming-Shu Kuo et al and Hualiang Shi extensively studied the surface modification of ultralow-k materials by CO 2 plasma and the results are published in their PhD dissertations 7,8 and in several papers. [9][10][11][12][13] They reported that i) CO 2 and O 2 plasma damage to ultralow-k films are comparable ii) there is lower atomic oxygen density in CO 2 discharge than O 2 discharge because of higher activation energy (11.5 eV) required to liberate atomic oxygen from CO 2 than from O 2 molecules (6 eV) -this is why there is supposedly a reduction in damage by CO 2 discharge with respect to O 2 for same operating conditions iii) the ashing rate of CO 2 increases with the addition of Ar at higher pressure (about 100 mTorr) than at lower pressure hence the addition of Ar is beneficial and dependent on pressure. Adding Ar brings about the dilution of the concentration of O 2 atoms that are liberated from CO 2 hence a lower damage to low-k.…”

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confidence: 99%

Modification of Ultra Low-k Dielectric Films by O₂and CO₂Plasmas

Olawumi

Levrau

Krishtab

et al. 2014

ECS J. Solid State Sci. Technol.

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Low-k materials developed for ULSI interconnects should have sufficient resistance to processing plasma. CO 2 plasma is being considered as a promising candidate for low damage photoresist ash and as a surface activation chemistry for self-assembled monolayers and atomic layer deposition on low-k materials. This article explores the interaction of two organosilicate (OSG) based low-k materials with different k-values (OSG2.4 and OSG2.2) with CO 2 plasma in both CCP and ICP-remote plasma chambers. Time dependent exposure of the materials to CO 2 plasma revealed quick and effective sealing of OSG2.4 surface whereas it takes longer time for OSG2.2. The sealing reduces further plasma damage and leads to accumulation of CO 2 in the pores of both materials. The same behavior occurs in ICP-remote plasma but without a complete sealing of the surface. This suggests the important role of ion bombardment. Damage to low-k by conventional O 2 plasma was studied alongside and it was found that for t < 60 s, O 2 plasma exerts more damage on OSG2.2 than CO 2 . This trend is reversed at t > 60 s. Furthermore, lesser time exposure to CO 2 plasma was investigated with respect to source power at constant pressure and it was discovered that damage although small, increases with varying source power. The performance enhancement of electronic circuits was majorly centered on reducing the transistor sizes, increasing transistor speed and density. However, in advanced technology nodes the performance of the resulting integrated circuits (IC) is greatly hindered by the resistance -capacitance (RC) delay experienced during the signal propagation within the interconnects.1 In order to solve this problem, the traditional Al was replaced by Cu, which has lower resistivity and SiO 2 with k = 4.0 was replaced by low dielectric constants (low-k) materials. Organosilicate glasses (OSG) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and/or by Spin-on Glass technology (SOG) are presently the most popular low-k materials.Photoresist strip using O 2 based plasma is a conventionally used processing technique but this has been found to be severely damaging to porous low-k materials. The modifications to the porous low-k materials lead to increased k-values from densification and hydrophilization.2-5 The CO 2 -based plasma has been reported to be less damaging with respect to the O 2 counterpart. Fuller et al. proposed the use of CO 2 based RIE plasma for photoresist stripping. Ming-Shu Kuo et al. and Hualiang Shi extensively studied the surface modification of ultralow-k materials by CO 2 plasma and the results are published in their PhD dissertations 7,8 and in several papers. 9-13 They reported that i) CO 2 and O 2 plasma damage to ultralow-k films are comparable ii) there is lower atomic oxygen density in CO 2 discharge than O 2 discharge because of higher activation energy (11.5 eV) required to liberate atomic oxygen from CO 2 than from O 2 molecules (6 eV) -this is why there is supposedly a reduction in damage by CO 2 discharge wi...

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“…The subsequent processing steps increased the substrate temperature and subjected the dielectric materials to both physical and chemical damage, the degree and nature of which depend on the chemistry and conditions used. 51 , 52 Unlike the remarkable thermal stability of the SOD Bakelite-polymer film (B), the attenuation spectra of both Samples F and E (not shown here) are similar to those of CVD POSS (D); they showed significant changes with storage times at 200°C. In the interest of brevity, we will focus only on the difference spectra to illustrate the chemical changes of the film following the high temperature storage.…”

Section: Resultsmentioning

confidence: 74%

Broadband Dielectric Spectroscopic Characterization of Thermal Stability of Low-k Dielectric Thin Films for Micro- and Nanoelectronic Applications

Sunday

Montgomery

Amoah

et al. 2017

ECS J. Solid State Sci. Technol.

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In this paper, we discuss the use of broadband microwaves (MW) to characterize the thermal stability of organic and hybrid silicon-organic thin films meant for insulation applications in micro- and nanoelectronic devices. We take advantage of MW propagation characteristics to extract and examine the relationships between electrical properties and the chemistry of prototypical low-k materials. The impact of thermal anneal at modest temperatures is examined to shed light on the thermal-induced performance and reliability changes within the dielectric films. These changes are then correlated with the chemical changes in the films, and could provide basis for rational selection of organic dielectrics for integrated devices.

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Plasma Processing of Low‐kDielectrics

Cited by 12 publications

References 109 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

Modification of Ultra Low-k Dielectric Films by O₂and CO₂Plasmas

Broadband Dielectric Spectroscopic Characterization of Thermal Stability of Low-k Dielectric Thin Films for Micro- and Nanoelectronic Applications

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Plasma Processing of Low‐kDielectrics

Cited by 12 publications

References 109 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

Modification of Ultra Low-k Dielectric Films by O2and CO2Plasmas

Broadband Dielectric Spectroscopic Characterization of Thermal Stability of Low-k Dielectric Thin Films for Micro- and Nanoelectronic Applications

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Modification of Ultra Low-k Dielectric Films by O₂and CO₂Plasmas