Properties of PEG, PPG and Their Copolymers: Influence on Copper Filling of Damascene Interconnects

Ryan, Kevin; Dunn, Kathleen; Eisden, J. van; Adolf, James D.

doi:10.1149/2.033312jes

Cited by 24 publications

(14 citation statements)

References 44 publications

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“…The aspect ratio of recessed features that can be filled by superconformal copper deposition is dependent on the dynamic range available between suppressed and actively growing surfaces. − The search for more effective suppressors has largely focused on more complex polyethers ranging from block copolymers to star-shaped block copolymers as well as exploration of the role of fixed charges. ,,− Herein, two different classes of polyethers, poloxamer and poloxamine, have been selected to examine the role of oligomer chemistry and secondary structure in the adsorption process (see Figure ). − Poly(propylene oxide) (PPO) is the largest component in both molecules.…”

Section: Resultsmentioning

confidence: 99%

SEIRAS Study of Chloride-Mediated Polyether Adsorption on Cu

et al. 2018

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Surface-enhanced infrared absorption spectroscopy is used to examine the co-adsorption of a selection of polyethers with Cl– under conditions relevant to superconformal Cu electrodeposition in CuSO4–H2SO4 electrolytes. In 0.1 mol/L H2SO4, a potential-dependent mixed SO4 2––H3O+/H2O layer forms on weakly textured (111) Cu thin-film surfaces. With the addition of 1 mmol/L NaCl, the SO4 2––H3O+/H2O adlayer is displaced and rapidly replaced by an ordered halide layer that disrupts the adjacent solvent network, leading to an increase in non-hydrogen-bonded water that makes the interface more hydrophobic. The altered wetting behavior facilitates co-adsorption of polyethers, such as poly(ethylene glycols), polyoxamers, or polyoxamines. Interfacial water is displaced by co-adsorption of the hydrophobic polymer segments on the Cl–-terminated surface, while the hydrophilic ether oxygens are available for hydrogen bond formation with the solvent. The combined polyether–Cl– layer serves as an effective suppressor of the Cu electrodeposition reaction by limiting access of Cuaq 2+ to the underlying metal surface. This insight differs from previous work which suggested that polymer adsorption is mediated by Cu+–ether binding.

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Section: Resultsmentioning

confidence: 99%

SEIRAS Study of Chloride-Mediated Polyether Adsorption on Cu

et al. 2018

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“…For nanoscale processes when appropriate fulfilling sub-micrometer features are required, polyethylene glycol (PEG) is added to the electroplating bath [ 8 , 9 , 10 , 11 ] in order to suppress the copper electrodeposition. However, the exact mechanism of polyethylene glycol is still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Bis-(sodium-sulfopropyl)-Disulfide and Polyethylene Glycol on the Copper Electrodeposited Layer by Time-of-Flight Secondary-Ion Mass Spectrometry

et al. 2023

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The interactions of the functional additives SPS (bis-(sodium-sulfopropyl)-disulfide) and polyethylene glycol (PEG) in the presence of chloride ions were studied by time-of-flight secondary-ion mass spectrometry (TOF-SIMS) in combination with cyclic voltammetry measurements (CV). The PEG, thiolate, and chloride surface coverages were estimated and discussed in terms of their electrochemical suppressing/accelerating abilities. The conformational influence of both the gauche/trans thiolate molecules, as well as around C-C and C-O of PEG, on the electrochemical properties were discussed. The contribution of the hydrophobic interaction of -CH2-CH2- of PEG with chloride ions was only slightly reduced after the addition of SPS, while the contribution of Cu-PEG adducts diminished strongly. SPS and PEG demonstrated significant synergy by significant co-adsorption. It was shown that the suppressing abilities of PEG that rely on forming stable Cu-PEG adducts, identified in the form C2H4O2Cu+ and C3H6OCu+, were significantly reduced after the addition of SPS. The major role of thiolate molecules adsorbed on a copper surface in reducing the suppressing abilities of PEG rely on the efficient capture of Cu2+ ions, diminishing the available copper ions for the ethereal oxygen of PEG.

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“…19 Figure 3 shows the galvanostatic curves of copper electrodeposition performed at the rotation speed of 1000 rpm. The experiments were carried out at a constant current density of 6 mA cm −2 and the electrolyte was the acidic copper methanesulfonate solution (0.02 M).…”

Section: Resultsmentioning

confidence: 99%

Influence of the Hydrophobic Groups on Quaternary Ammonium Additives for Copper Electrodeposition

Wang

Hua

Yin

et al. 2014

J. Electrochem. Soc.

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A series of quaternary ammonium compounds with different hydrophobic groups as spacers were synthesized. The influence of the hydrophobic groups on the additives for copper electrodeposition was investigated using a galvanostatic measurement on a RDE electrode. The increase of the length of the alkyl chain within the compounds enhances the suppressing capability. The introduction of a hydroxyl group or a phenyl ring into the hydrophobic groups in the molecular structures reduces the suppressing capacity. The results obtained from SEM measurements indicate that the presence of the quaternary ammonium compounds in the electrolytes may produce regular and relative leveling morphologies of copper deposits. The via-filling experiments without SPS exhibit that an almost complete filling was achieved for compound 1d (C 6 alkyl chain as a hydrophobic group), whereas a bad filling was obtained for compound 1a (C 3 -OH chain as a hydrophobic group). With SPS, the vias were perfectly filled both for compound 1a and 1d. However, the initial increment of growth was still conformal for the compound 1a. These results indicate the influence of the hydrophobic groups of the quaternary ammonium compounds on the filling behaviors and they are in agreement with the galvanostatic measurements at different electrode rotation speeds.Copper electrodeposition from acidic electrolytes has been widely used in electronic industry for both printed circuit board (PCB) and integrated circuit (IC) applications. The composition of the acidic electrolyte mainly contains cupric ion, acid and additives. Sulfuric acid or methanesulfonic acid (MSA) 1,2 is usually used as a supporting electrolyte. The presence of the additives in the electrolytes results in the improvement of the deposit properties, such as morphology, brightness, and grain refinement. Typically, the additives can be three (accelerator, suppressor, leveler) components for the filling of trenches and vias. 3,4 However, both suppressor and leveler can be taken as inhibiting additives due to their suppressing effect for copper deposition rate. 5 Because of the presence of convection-dependent adsorption (CDA), 5,6 the filling performance for via metallization can be improved by a leveler and the copper via-filling can be performed with a single organic additive. [7][8][9] Levelers are positively charged molecules 10 that produce the deposits topographical homogeneities in electrodeposition. The commonly used levelers in copper electrodeposition are nitrogencontaining or quaternary ammonium compounds including highmolecular weight molecules (e.g., JGB), 11 quaternary ammonium surfactants 12,13 and polymers. 14,15 Recently, a number of new quaternary ammonium compounds have been used as levelers such as Nbutyl-methyl piperidinium bromide, 16 diallylamine-type copolymer 7,8 and branched quaternary ammonium surfactant. 17 Quaternary ammonium compounds contain the quaternary nitrogen atoms in their backbones as the charged species and they also possess the attached hydrophilic or hydrophobic ...

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Properties of PEG, PPG and Their Copolymers: Influence on Copper Filling of Damascene Interconnects

Cited by 24 publications

References 44 publications

SEIRAS Study of Chloride-Mediated Polyether Adsorption on Cu

SEIRAS Study of Chloride-Mediated Polyether Adsorption on Cu

Interaction of Bis-(sodium-sulfopropyl)-Disulfide and Polyethylene Glycol on the Copper Electrodeposited Layer by Time-of-Flight Secondary-Ion Mass Spectrometry

Influence of the Hydrophobic Groups on Quaternary Ammonium Additives for Copper Electrodeposition

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