Investigation on hexamethyldisilazane vapor treatment of plasma-damaged nanoporous organosilicate films

Rajagopalan, T.; Lahlouh, Bashar; Lubguban, Jorge; Biswas, N.; Gangopadhyay, Shubhra; Sun, J.; Huang, Dinghai; Simon, Sindee L.; Toma, Dorel; Butler, R.

doi:10.1016/j.apsusc.2005.08.060

Cited by 29 publications

(23 citation statements)

References 19 publications

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“…[64][65][66][67][68][69] In general, the repair process may involve wet or vapor phase capping by alkyl silanes, such as hexamethyldisilazane (HMDS), of the majority of highly polar SiOH groups, generated during plasma damage. Of these repair processes, vapor phase reactions are preferred due to good compatibility with existing equipment.…”

Section: Damage Repair and /Or Preventionmentioning

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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Section: Damage Repair and /Or Preventionmentioning

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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“…4 However, it is not clear whether the device characteristics after those treatments were directly related to the reduction of the hydroxyl group at the SiO 2 surface. [2][3][4][5] UV light has been used to induce the structural modification in the SiO 2 . 6,7 It was reported that the photolysis using UV light could modify the bond structures of the SiO 2 , including the elimination of hydroxyl groups.…”

mentioning

confidence: 99%

Effect of UV Irradiation on Threshold Voltage and Subthreshold Slope in Pentacene TFT

Kim

Lee

2008

Electrochem. Solid-State Lett.

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We report the influence of UV irradiation on the electrical properties of pentacene thin-film transistors ͑TFTs͒ with SiO 2 gate insulator. The threshold voltage ͑V th ͒ shifted from −9.0 to −5.1 V and subthreshold slope reduced from 3.6 to 1.1 V/dec by the treatment before pentacene deposition. The UV treatment reduced the surface energy by removing the hydroxyl groups at the SiO 2 surface. Thus, molecular packing of pentacene on the UV-treated SiO 2 was improved, lowering the ͉V th ͉ value via the reduction of trap densities in the channel region. The decrease in interface state density reduced the subthreshold slope.A thin-film transistor ͑TFT͒ with device parameters of low threshold voltage ͑V th ͒, zero turn-on voltage ͑V to ͒, and small subthreshold slope ͑S͒ is desirable as a switch device for the application of active-matrix displays. In p-type pentacene ͑PEN͒ TFT with SiO 2 dielectric layers, low electric performances with high ͑V th ͒, large positive ͑V to ͒, and large S values were commonly observed. 1-4 This might be due to the hydroxyl group ͑OH − ͒ at the SiO 2 surface, which acts as an electron trapping center, leaving the mobile holes in the channel. 1-4 The surface treatment with hexamethyldisilazane changed the SiO 2 surface from a OH-terminated surface to a CH 3 -terminated one, improving the V to , V th , and S values. 2,3 The formation of built-in dipole at the SiO 2 surface using phenethylchlorosilane also showed the performance improvement of PEN devices. 4 However, it is not clear whether the device characteristics after those treatments were directly related to the reduction of the hydroxyl group at the SiO 2 surface. [2][3][4][5] UV light has been used to induce the structural modification in the SiO 2 . 6,7 It was reported that the photolysis using UV light could modify the bond structures of the SiO 2 , including the elimination of hydroxyl groups. 7 UV irradiation on the SiO 2 surface could reduce the OH − groups effectively without rendering negative charges at the SiO 2 /PEN interface. Because the reduction of OH − at the SiO 2 surface could decrease the surface energy, it was thought that lower surface energy could also improve the grain interconnectivity. 8 Thus, it was expected that UV treatment on the SiO 2 surface in a vacuum could improve the device performances.In this study, we report the effects of UV irradiation on the surface electronic states and the performance of PEN-TFT with SiO 2 dielectric layer. Chemical compositions and bonding structures of the gate insulator ͑SiO 2 ͒ were investigated using synchrotron radiation photoemission spectroscopy ͑SRPES͒. The surface morphology of PEN film was examined using atomic force microscopy ͑AFM, digital instrument͒ and scanning electron microscopy ͑SEM͒. From these, the influence of UV irradiation on the electrical performance of PEN-TFT is discussed.Devices were fabricated on a highly doped n-Si ͑ϳ5 ⍀ cm͒ substrate with thermally grown SiO 2 ͑300 nm thick, insulator capacitance C i = 10 nF/cm 2 ͒, which functioned as the gate ...

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“…When the HMDS-treated sample was exposed to the highest RH, k eff increased by only 0.3% above the initial condition. [18][19][20] The change in effective dielectric constant is shown in Fig. 10.…”

Section: Resultsmentioning

confidence: 99%

“…21 A process to repair the damaged low-k may be required. [19][20][21] An additional CMP step is required for the planarization of the nonconformal interlayer dielectric. The air cavity occupies only a portion of the intralayer dielectric region.…”

mentioning

confidence: 99%

Air-Gaps for High-Performance On-Chip Interconnect Part II: Modeling, Fabrication, and Characterization

Park

Allen

Kohl

2008

Journal of Elec Materi

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Air-gaps are the ultimate low-k material in microelectronics due to air having a low dielectric constant close to 1.0. The interconnect capacitance can further be reduced by extending the air-gaps into the interlayer dielectric region to reduce the fringing electric field. An electrostatic model (200 nm half-pitch interconnect with an aspect ratio of 2.0), was used to evaluate the dielectric properties of the air-gap structures. The incorporation of air-gaps into the intrametal dielectric region reduced the capacitance by 39% compared with SiO 2 . Extending the air-gap 100 nm into the top and bottom interlayer SiO 2 region lowered the capacitance by 49%. The ability to fabricate air-gaps and Ôextended air-gapsÕ was demonstrated, and the capacitance decrease was experimentally verified. Cu/air-gap and extended Cu/air-gap interconnect structures were fabricated using high-modulus tetracyclododecene (TD)-based sacrificial polymer. The aspect ratio of the air-gap was 1.8 and the air-gap was extended 80 nm and 100 nm into the top and bottom interlevel SiO 2 region, respectively. The measured effective dielectric constant (k eff ) of the Cu/air-gap and the extended Cu/air-gap structures with SiO 2 interlevel dielectric was 2.42 and 2.17, respectively. The effect of moisture uptake within the extended Cu/air-gap structure was investigated. As the relative humidity increased from 4% to 92%, the k eff increased by 7%. Hexamethyldisilazane was used to remove adsorbed moisture and create a hydrophobic termination within the air-cavities, which lowered the effect of humidity on the k eff . A dual Damascene air-gap and extended air-gap fabrication processes were proposed and the challenges of using a sacrificial polymer placeholder approach to form air-cavities are compared to other integration approaches of dual Damascene air-gap.

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Investigation on hexamethyldisilazane vapor treatment of plasma-damaged nanoporous organosilicate films

Cited by 29 publications

References 19 publications

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

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

Effect of UV Irradiation on Threshold Voltage and Subthreshold Slope in Pentacene TFT

Air-Gaps for High-Performance On-Chip Interconnect Part II: Modeling, Fabrication, and Characterization

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