The Influence of Adsorption Kinetics on Copper Superfilling for Dual Damascene

Liske, R.; Krause, Robert; Uhlig, Benjamin; Gerlich, Lukas; Bott, Sascha; Wislicenus, Marcus; Preuße, Axel

doi:10.1149/2.0261606jes

Cited by 5 publications

(4 citation statements)

References 27 publications

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“…Although in production applications PEG and Cl are commonly used together with the accelerator additive SPS, studying the sole PEG-Cl system in a first step is naturally fundamental to understand the whole SPS-PEG-Cl system, where the interplay between SPS and PEG is crucial. [22][23][24]27,28 Moreover, the achievement of the superfilling of TSVs in a PEG-Cl bath without SPS 15 points to the technical importance of this system and further motivates its study. In the past, extensive modeling efforts were already devoted to the effect of PEG and Cl − .…”

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confidence: 99%

Copper Electroplating with Polyethylene Glycol

Yang

Dianat

Bobeth

et al. 2017

J. Electrochem. Soc.

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Additives play an important role in electrochemical deposition and understanding their working mechanism is a great challenge. In cyclic voltammetry measurements of copper deposition, hysteresis is ubiquitously observed. Correct prediction of hysteresis behavior is an important test for deposition models. In previous models, including poly(ethylene glycol) (PEG) and chloride ions as additives, a common assumption to explain the hysteresis is the consumption of additives during copper deposition. However, second-ion mass spectrometry measurements often detected comparatively low levels of impurities in deposits. Therefore, we propose here an alternative mechanism for explaining hysteresis curves without invoking additive consumption. Essential ingredients of our models are: (i) a strongly nonlinear dependence of the maximal possible PEG coverage on the chloride coverage on the copper surface, (ii) a nonlinear dependence of the deposition current on the PEG surface coverage, and (iii) an additional activation of the desorption of additives with increasing copper deposition current. We demonstrate that our model reproduces characteristic features of cyclic voltammograms measured under vastly different conditions and exhibiting pronounced hysteresis. Furthermore, simulations are compared well to PEG adsorption/desorption experiments with varying additive concentrations. The proposed model may serve to describe deposition situations with negligible additive consumption.

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confidence: 99%

Copper Electroplating with Polyethylene Glycol

Yang

Dianat

Bobeth

et al. 2017

J. Electrochem. Soc.

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“…The potential process would require a suitable dielectric etch followed by metal superfill. Superfill of metals is required in order to achieve a uniform bottom-up fill in the interconnect features [6] [7]. Although there were many schemes investigated to deposit copper, they had significant drawbacks depending upon the method chosen.…”

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confidence: 99%

Electroplating: Applications in the Semiconductor Industry

Jhothiraman¹,

Balachandran²

2019

ACES

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There is a lot of research that has been done on electroplating of metals depending on the type of application. In this chapter, the importance of this technique to the semiconductor industry is discussed in detail from an experimental as well as a modeling standpoint. In particular, the effect of solution variables i.e. chloride, accelerator, suppressor on copper electrodeposition is discussed. This knowledge is applied to achieve a defect-free, bottom-up metal/copper fill that eventually, is one of the most critical processes in this billion-dollar industry.

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“…Extensive research efforts over the past few decades have led to the development and continued improvement and understanding of electrodeposition processes suitable for deposition of dense films of copper in recessed sub-micron features for integrated circuit applications. [1][2][3][4][5][6] Processes that yield locally enhanced deposition at the bottom of recessed features (termed "bottom-up", superconformal filling, or "superfilling") rely on additives that adsorb with differential coverage on the various surfaces of the recessed features causing locally inhibited or enhanced deposition rates of the copper film. [7][8][9] Since the development of the first electrodeposition process for superconformal filling of interconnect features, the Damascene process, models have been developed that successfully predict the characteristics of the systems capable of superfilling.…”

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confidence: 99%

“…13 A well-characterized system using an acid copper sulfate electrolyte with three or four additives has also been extensively studied and successfully modeled by the Curvature Enhanced Accelerator Coverage (CEAC) model. [2][3][4][5][6][10][11][12] During deposition, superfilling is achieved when a rate-accelerating additive (typically a thiol) competitively displaces a rate-suppressing additive (often a polyether), at advancing concave surfaces. Displacement of the inhibiting additive leads to enhanced deposition rates at concave sur-faces, such as the copper films advancing from the bottom of recessed features.…”

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confidence: 99%

Effects of Acetic Acid, Tartaric Acid and Pb UPD on Cu Electrodeposition in Sub-Micron Trenches

Pounds¹,

Sieradzki²,

Erlebacher³

et al. 2017

J. Electrochem. Soc.

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The effects of acetic acid, tartaric acid, and Pb-mediated underpotential deposition (UPD) on the filling characteristics of copper electrodeposition in sub-micron trenches were studied. In the absence of other electrolyte additives, potentiostatic and galvanostatic depositions from electrolytes containing organic acids were capable of producing dense filling in sub-micron trenches due to higher deposition rates at the trench bottoms compared to the side-walls and adjacent surfaces surrounding the recessed features. The mechanism for dense filling of trenches from depositions in the organic acid containing electrolytes did not appear to match previously identified mechanisms for superfilling associated with surfactant effects. Instead, the differential deposition rates across the trench profile were attributed to textural and/or structural differences in the copper seed layer as the copper deposition rates were enhanced at both the bottom and adjacent surfaces surrounding the trenches, or sidewalls of the trench depending on the organic acid species present in the electrolyte. The organic acids induced conformal and smooth depositions improving with increasing overpotential. Pb mediated UPD yielded smooth, conformal films relative to non-mediated deposition under otherwise identical conditions. The density of the UPD mediated films was best at higher Pb coverage during Cu deposition.

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The Influence of Adsorption Kinetics on Copper Superfilling for Dual Damascene

Cited by 5 publications

References 27 publications

Copper Electroplating with Polyethylene Glycol

Copper Electroplating with Polyethylene Glycol

Electroplating: Applications in the Semiconductor Industry

Effects of Acetic Acid, Tartaric Acid and Pb UPD on Cu Electrodeposition in Sub-Micron Trenches

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