Characterization of Ultrathin Electroless Barriers Grown by Self-Aligned Deposition on Silicon-Based Dielectric Films

Chen²,

et al. 2012

Langmuir

Taking plasma-enhanced chemical vapor deposited porous SiOCH (p-SiOCH) and octadecyltrichlorosilane (OTS) as model cases, this study elucidates the chemical reaction pathways for alkyl-based self-assembled monolayers (SAMs) on porous carbon-doped organosilica films under N(2)-H(2) vacuum plasma illumination. In contrast to previous findings that carboxylic groups are found in alkyl-based SAMs only by exposure to oxygen-based plasma, this study discovers that, upon exposure to reductive nitrogen-based vacuum plasma, surface carboxylic functional groups can be instantly formed on OTS-coated p-SiOCH films. Particular attention is given to developing a multisurface modification process, starting with the modification of p-SiOCH films by N(2)-H(2) plasma and continuing with SAM deposition and plasma patterning; this ultimately leads to site-selective seeding for the spatially controlled fabrication of Cu-wire metallization by electroless deposition. Plasma diagnosis and X-ray near-edge absorption and Fourier transform infrared spectroscopies show that, by adequately controlling the plasma parameters, the bulk of the p-SiOCH films are free from plasma damage (in terms of degradation in bonding structures and electrical properties); the formation of the seed-trapping carboxylic functional groups on the surface, the key factor for the validity of this new seeding process, is due to a water-mediated chemical oxygenation route.

Section: Methodsmentioning

confidence: 99%

“…The processing conditions of the SC-1 surface modification, seeding, and electroless deposition, as well as constituents of the baths, have been detailed elsewhere. 21…”

Section: Methodsmentioning

confidence: 99%

Site-Selective Electroless Metallization on Porous Organosilica Films by Multisurface Modification of Alkyl Monolayer and Vacuum Plasma

Chen²,

et al. 2012

Langmuir

“…Over the years, the electroless nickel plating (ENP) technique has experienced a rapidly increasing demand in a broad spectrum of industrial practices, − development in nanotechnology recently, − etc. In an ENP process, the nickel ions are generally reduced on conductive surfaces, commonly the just-deposited nickel frontier, in the presence of chemical reducing agents, in place of an external electric current .…”

Section: Introductionmentioning

confidence: 99%

Role of Cu²⁺ as an Additive in an Electroless Nickel−Phosphorus Plating System: A Stabilizer or a Codeposit?

Hong

2006

Chem. Mater.

The effect of cupric (Cu 2+ ) ion as an additive in the acidic electroless nickel plating (ENP) bath on the characteristics of the resulting nickel-phosphorus (Ni-P) alloys was investigated mainly with X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray (EDX) spectrometry. Cupric ions in the acidic ENP bath using hypophosphite anions as reductants have been reported ambiguously as stabilizers or codeposit constituents. In this work, the critical concentration of added copper salts, CuSO 4 ‚ 5H 2 O, that starts to inhibit the ENP process was determined to be ca. 536 mg/L. In general, the deposition rate, surface morphology, and pit formation on the surface of as-deposits are significantly improved with Cu 2+ addition at concentrations less than the critical value. The electroless nickel alloys were shown as a mixture of an amorphous deposit and a crystalline copper metal rather than as amorphous alloys alone. 1,2 During the initial stage of the electroless plating process, the copper contents in as-deposits were found to decrease rapidly with plating time from the EDX analyses. The X-ray photoelectron spectroscopy result also confirms that copper is the preferred deposited species during the initial stage of the ENP process. The theoretical model 3 is revised by taking into account the effect of adsorbed cupric ions on the shift in the depth of the net nuclear potential of the electroless nickel frontier, and successfully predicts the deposition rates. Moreover, as predicted by the revised model, the adsorbed cupric ions on the justdeposited Ni-Cu-P frontier could enhance the adsorption of hypophosphite anions and, accordingly, the deposition rates.

“…4,5 In addition, similar studies are the focus of research in many parts of the world. [5][6][7][8] Extensive investigations of the structure of electroless deposited Co 0.9 W 0.02 P 0.08 films and their evolution with thermal annealing have been conducted. [7][8][9] The request of alternatives for electrodeposited chromium brings another aspect of interest in electrodeposited Co-W-P alloy.…”

mentioning

confidence: 99%

Crystalline and Amorphous Electroless Co-W-P Coatings

Armyanov

Valova

Franquet

et al. 2005

J. Electrochem. Soc.

Electroless deposition onto polycrystalline ͑Cu, Au͒ and amorphous ͑Ni-P͒ substrates was applied to prepare Co-W-P coatings of two types: crystalline ͑hexagonal close packed, hcp͒, with low phosphorus content about 2.4-2.7 atom %, and amorphous, with P concentration within 7.4-8.3 atom %. Tungsten content varied typically in the narrow range of 2.9-3.7 atom % in both types of coatings. Atomic force microscopy revealed substantial difference in their morphology. Polycrystalline Co-W-P coatings consist of grains of stacked plates ͑lamellas͒, confirmed by transmission electron microscopy also. Amorphous films are smoother and uniform. The crystalline structure promotes the surface oxidation to a higher extent than the amorphous structure, as shown by the X-ray photoelectron spectroscopy ͑XPS͒. Auger electron spectroscopy depth profiles display oxidation, smoothly diminishing toward the inside of the crystalline films. Amorphous coatings are oxidized only at the surface. Inside both types of coatings, however, all alloy components are in nonoxidized form, according to XPS data. Differential scanning calorimetry ͑DSC͒ studies of amorphous coatings revealed three transformation peaks, ascribed to a crystallization of hypoeutectic alloy and a transition of Co-based hcp phase into face-centered cubic. Magnetic properties variation with temperature is in agreement with DSC results.