Comparative Study of Cu Diffusion in Ru and Ru-C Films for Cu Metallization

Chen, Chun-Wei; Jeng, Jiann Shing; Chen, Jen‐Sue

doi:10.1149/1.3479383

Cited by 13 publications

(6 citation statements)

References 33 publications

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“…1. Other group [34][35][36] also reported that the barrier performance of Ru-C is significantly improved compared to Ru.…”

Section: Resultsmentioning

confidence: 96%

“…Chen and his coworkers reported that columnar Ru grain boundaries were stuffed by C and the failure temperature of the whole system was improved by doping C in Ru. 34 The direct electroplating of Cu on a 5nm Ru-C film was also demonstrated. L. F. Nie 41 et al studied in detail the effect of C on the resistivity and thermal stability of C-doped Cu film after annealing.…”

Section: Resultsmentioning

confidence: 98%

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The Inhibition of Enhanced Cu Oxidation on Ruthenium∕Diffusion Barrier Layers for Cu Interconnects by Carbon Alloying into Ru

Xie

Müeller

Waechtler

et al. 2011

J. Electrochem. Soc.

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The inhibition of Cu oxidation by alloying C into the Ru/TaN barrier stack is investigated. By using in-situ XRD measurement, severe copper oxide formation was observed for the Cu/Ru/barrier system during annealing process in He atmosphere. This phenomenon is explained using thermodynamics from the viewpoint of Gibbs free energy of oxide formation. The Cu oxidation can be inhibited by alloying C into the Ru layer, and the more C content in the RuC layer, the more evident the inhibition effect. The RuC/TaN stack also shows better diffusion barrier properties than the Ru/TaN bi-layer. Atomic layer deposition of Cu 2 O on the RuC substrate was carried out and reduction of the Cu 2 O to Cu was observed. The mechanism of inhibition of Cu oxidation on C alloyed Ru was investigated by a first principles calculation based on the density functional theory.As the interconnect line width continually scales down, the reliability problem induced by stress induced voiding (SiV) and electromigration (EM) becomes severe. 1-6 The SiV and EM problem are mainly caused by poor adhesion between Cu and the glue layer or capping layer. 1, 6-11 It is found that the oxidation of Cu or barrier layer will degrade the adhesion between Cu and the glue layer, 1, 12-14 resulting in delamination during chemical mechanical polishing (CMP) and reliability problems. Cu oxidation Cu can also increase the line resistance and thus increase the RC delay and degrade the performance of the devices. During the back end of line (BEOL) manufacturing process, Cu oxidation is easily observed because of many thermal processes and the unavoidable oxygen processes such as electrochemical deposition (ECD) of Cu. In order to inhibit Cu oxidation and improve the reliability of Cu interconnects, many methods have been proposed, such as using Ti instead of Ta as the Cu adhesion layer, 9 or adding an oxygen adsorption layer, such as Al 1 or Ti 15 on the pure ECD-Cu film before annealing.Recently, novel materials such as Ru 16,17,19 and Co 16, 20 etc. with low resistivity have been proposed to replace Ta as Cu adhesion layer because of the ability of direct ECD of Cu on their surface, which is beneficial for conformal ECD Cu gap filling. [16][17][18] Ru is considered as one of the most promising material as Cu adhesion layer in the future technology node. 17,19,21,22 It is reported that the predicted circuitperformance using the Ru based barrier was 10% higher than that with a Ta barrier and the operating-speed distribution was estimated to be less than 5% for the 22 nm-node CMOS generation. 19 However, there are still some concerns such as severe oxidation of copper and galvanic corrosion during the CMP process. 16 In this work, the effect of Ru on enhanced Cu oxidation was studied and by adding C into Ru, the inhibition of Cu oxidation and promotion of Cu 2 O reduction were studied.Experimental P-type Si (100) substrates were loaded into the vacuum chamber through a loadlock after standard chemical cleaning. The base pressure of the vacuum was 2 × 10 −7 mbar. TaCN a...

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“…1. Other group [34][35][36] also reported that the barrier performance of Ru-C is significantly improved compared to Ru.…”

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 98%

The Inhibition of Enhanced Cu Oxidation on Ruthenium∕Diffusion Barrier Layers for Cu Interconnects by Carbon Alloying into Ru

Xie

Müeller

Waechtler

et al. 2011

J. Electrochem. Soc.

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show abstract

“…Pmax is found to be as low as 15.6~241.2 nW at VDD of 1.5~3.0 V, indicating rather low power consumption during switching. Figure 3(c) summarizes the VDD of the above mentioned reported inverters [13][14][15][16][17][18][19][20][26][27][28][29][30][31][32][33][34][35][36][37][38][39], commonly in range of 2~100 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 F o r P e e r R e v i e w V. Our inverter has realized the lowest VDD of 1.5 V, with yet high performance. Such low VDD lead to significantly low power consumption.…”

Section: Methodsmentioning

confidence: 99%

“…However, there is limited development of high performance p-type oxides [12]. P-type carbon nanotubes (CNTs) [13,14], organic semiconductors [15,16], poly-silicon [17,18], and metal compound [19,20], are developed to construct complementary inverters with n-type oxides. However, the process compatibility, thermal stability, p-type purity, flexibility, and performances such as supply voltage, gain, and noise margin level are commonly unsatisfactory.…”

mentioning

confidence: 99%

Oxide-Based Complementary Inverters With High Gain and Nanowatt Power Consumption

Yuan

Yang

et al. 2018

IEEE Electron Device Lett.

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Oxide semiconductors are ideal candidates for flexible and transparent electronics. Here, we report complementary inverters based on p-type tin monoxide and n-type indium-gallium-zinc-oxide thin-film transistors. The inverters have a gain of 63 at a supply voltage, VDD, of 1.5 V with a maximum static power consumption of 15.6 nW, and a gain of 226 at a VDD of 3.0 V with a maximum power consumption of 241.2 nW. A five-stage ring oscillator (RO) based on the complementary inverters are able to operate at 1.04 kHz, with full amplitude oscillations at a VDD of 1.5 V. All the inverters and RO are fabricated on silicon wafers but at a maximum processing temperature of 225 o C, so that the results are relevant to possible flexible applications. The extremely low power consumption of nanowatt, high gain, kHz operation, and possible flexibility of the fabricated complementary components are well suited to meet the requirements of wearable electronics, internet of things technology, etc. Index Terms-Complementary inverter, indium gallium zinc oxide (InGaZnO or IGZO), tin monoxide (SnO), low-power, high gain, ring oscillator (RO), thin-film transistor (TFT).

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“…4a, there are some dark grains near the interfaces of barrier layer and the occurrence of delamination at the interface between TaN L and Si, indicating the catastrophic failure of Ru/TaN L barrier layers. It is well known that the CueTa and CueRu system are essentially immiscible [7,12,17]. Thus, the dark grains observed are mainly composed of Cu 3 Si phase as proved by XRD results.…”

Section: Resultsmentioning

confidence: 57%

Improved diffusion barrier performance of Ru/TaN bilayer by N effusion in TaN underlayer

Wang

Cao

et al. 2012

Materials Chemistry and Physics

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Comparative Study of Cu Diffusion in Ru and Ru-C Films for Cu Metallization

Cited by 13 publications

References 33 publications

The Inhibition of Enhanced Cu Oxidation on Ruthenium∕Diffusion Barrier Layers for Cu Interconnects by Carbon Alloying into Ru

The Inhibition of Enhanced Cu Oxidation on Ruthenium∕Diffusion Barrier Layers for Cu Interconnects by Carbon Alloying into Ru

Oxide-Based Complementary Inverters With High Gain and Nanowatt Power Consumption

Improved diffusion barrier performance of Ru/TaN bilayer by N effusion in TaN underlayer

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