Damage mechanism in low-dielectric (low-k) films during plasma processes

Jinnai, Butsurin; Nozawa, Toshihisa; Samukawa, Seiji

doi:10.1116/1.3010721

Cited by 43 publications

(26 citation statements)

References 18 publications

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“…Jinnai et al 38 suggested that photon irradiation plays an important role in the damage process and enhances the breakage of Si-C bonds. In their study, Ar and SF 6 plasma irradiation was first compared with Ar and SF 6 neutral beam irradiation.…”

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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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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“…This irradiation often produces charge embedded within dielectrics, which can lead to dielectric damage. 1,2 Typically, the capacitance versus voltage relationship ͑C-V͒ gives us details on the deviation of dielectrics from ideal behavior. 3 This letter shows the relationship between C-V characteristics and the induced charge in organosilicate Si-COH deposited on silicon after VUV/UV irradiation.…”

Section: Effect Of Vacuum Ultraviolet and Ultraviolet Irradiation On mentioning

confidence: 99%

Effect of vacuum ultraviolet and ultraviolet Irradiation on capacitance-voltage characteristics of low-k-porous organosilicate dielectrics

Sinha

Lauer

Nichols

et al. 2010

Applied Physics Letters

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High frequency capacitance-voltage (C-V) measurements are used to determine the effects of vacuum ultraviolet (VUV) and ultraviolet (UV) irradiation on defect states in porous low-k organosilicate (SiCOH) dielectrics. The characteristics show that VUV photons depopulate trapped electrons from defect states within the dielectric creating trapped positive charge. This is evidenced by a negative shift in the flat-band voltage of the C-V characteristic. UV irradiation reverses this effect by repopulating the defect states with electrons photoinjected from the silicon substrate. Thus, UV reduces the number of trapped positive charges in the dielectric and can effectively repair processing-induced damage.

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“…9 In addition, the potentially large fluxes of energetic photons, particularly in the VUV range, have been shown to cause a number of unwanted effects, including differential charging of patterned structures, 10 and the creation of bulk and interfacial trap states that contribute to damage induced by leakage currents. 11 Additionally, recent work has reported that plasma exposure can adversely change the mechanical properties of low-k dielectrics, which will worsen dielectric reliability and degrade device performance. 12,13 Our previous work studied the effect of water uptake on the mechanical properties of these low-k dielectrics.…”

Section: Introductionmentioning

confidence: 99%

Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass

Guo

Jakes

Banna

et al. 2014

Journal of Applied Physics

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The effect of water uptake on the mechanical properties of low-k organosilicate glass Plasma damage effects on low-k porous organosilicate glass J. Appl. Phys. 108, 094110 (2010); 10.1063/1.3506523 Short-ranged structural rearrangement and enhancement of mechanical properties of organosilicate glasses induced by ultraviolet radiationThe effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on the mechanical properties of low-k porous organosilicate glass (SiCOH) dielectric films were investigated. Nanoindentation measurements were made on SiCOH films before and after exposure to an electron-cyclotron-resonance plasma or a monochromatic synchrotron VUV beam, to determine the changes of film hardness, elastic modulus, and crack threshold due to these exposures. This permits the effects of ion bombardment and photon bombardment to be analyzed separately. The role of energetic ions was examined with a variety of inert plasma-exposure conditions. The role of VUV photons was analyzed as a function of synchrotron photon energy. It was found that both energetic ions and VUV photons with energies larger than the bond energy of the Si-O bond cause a significant increase in film hardness along with a smaller increase in elastic modulus and crack threshold. Differential Fourier transform infrared spectra and x-ray photoemission spectroscopy results show that the energetic ions affect the SiCOH properties mainly through physical bombardment, during which the ions transfer their momentum to the Si-O-Si backbone and transform them into more energetically stable Si-O-Si network structures. This results in the Si-O-Si network structures becoming densified. VUV photons assist reaction that increase the number of bridging O 3 Si-O-SiO 3 bonds and deplete nonbridging O 3 Si-O and C-SiO 3 bonds. This increased degree of cross linking in porous organosilicate dielectrics can substantially enhance their hardness and elastic modulus while showing no significant film shrinkage or densification. V C 2014 AIP Publishing LLC. [http://dx.

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Damage mechanism in low-dielectric (low-k) films during plasma processes

Cited by 43 publications

References 18 publications

Electrical Reliability Challenges of Advanced Low-k Dielectrics

Electrical Reliability Challenges of Advanced Low-k Dielectrics

Effect of vacuum ultraviolet and ultraviolet Irradiation on capacitance-voltage characteristics of low-k-porous organosilicate dielectrics

Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass

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