Wang et al. Nanoscale Research Letters 2011, 6:483 http://www.nanoscalereslett.com/content/6/1/483 Table 1 shows chemical formula and nomenclature of the self-assembled organosilanes commonly used in electronic industry or previous researches. From the results of Table 1, we can learn that the mercapto-silane (SAM1), amino-silane (SAM2 [15]), and pyridyl-silane (SAM4) are excellent coupling agents between substrates and Cu to act as interfacial adhesion enhancer. Compared with aliphatic groups, larger volume organosilanes with the aromatic ring (SAM4, SAM5, SAM6, and SAM7 [16]) sterically hinder copper diffusion. Therefore, the ideal organosilane molecules should be with both aromatic ring and terminal function group which have high reactivity with copper. In recent years, studies have been mainly focused on the approaches of Cu metallization including chemical vapor deposition, physical vapor deposition, electroless deposition (ELD), and electroplating. Cu ELD was espe- cially emphasized in future interconnect technology. However, the organosilanes utilized in this technique were mainly mercaptopropyltrimethoxysilane (MPTMS; SAM1 [3,9-11]) and aminopropyltrimethoxysilane (APTMS; SAM2 [4,9,17]). So far, no research has been carried out on the modification of organosilane, and it is necessary to design and synthesize functional organosi- lane molecule. Our group has focused on the triazinedithiols (TDTs) [18-20] for many years. With two mercapto groups and aromatic ring with nitrogen atom, TDTs combine the advantages of SAM1 and SAM2, which have high reactiv- ity with copper. Besides, nitrogen atom that existed between the two mercapto groups is different with SAM4, which possesses a better space position for copper immobilization. But the triazinedithiols could not react with the substrate for lack of silane group (Si-(OR)3). Therefore, our research concentrates on the combination of triazinedithiols and silane (see Figure 1). In this paper, we demonstrate a designed and synthesized triazinedithiolsilane molecule - 6-(3-triethoxysilylpropyl) Table 1 Chemical formula and nomenclature of the self- assembled organosilanes usually used in previous researches Molecule Chemical formula Name SAM1 SAM212 SAM3 SAM4 SAM5 SAM6 SAM713 HSCH2CH2CH2Si (3-Mecaptopropyl)trimethoxysilane (OCH3)3 H2NCH2CH2CH2Si (3-Aminopropyl)trimethoxysilane (OCH3)3 CH3CH2CH2Si(OCH3)3 (n-Propyl)trimethoxysilane 3-[2-(Trimethoxysilyl)ethyl]pyridine 2-(Trimethoxysilyl)ethylbenzene Phenyltrimethoxysilane 2-(Diphenylphosphino) ethyltriethoxysilane Page 2 of 5 amino-1,3,5-triazine-2,4-dithiol monosodium salt (abbre- viation, TESPA, see Figure 1) according to the strategies mentioned. TESPA has three active sites which refer to two mercapto groups [21] and a nitrogen atom. We also preliminarily investigate the adhesion strength between ELD copper film and TESPA SAM to verify whether it can be used as adhesion enhancer and diffusion barrier in device applications. Experimental The chemical structure of TESPA was identified by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), and mass spectroscopy (MS) (The data are available in Additional file 1). 1H NMR and 13C NMR spectra were recorded by Bruker AC 400 with 500 MHz (Bruker Daltonics, Billerica, MA, USA). FT-IR spectra were measured using Bruker TEN- SOR 37 (Bruker Daltonics). MS was recorded by LCQ- Fleet (Thermo Scientific, Waltham, MA, USA). TESPA SAM was fabricated on epoxy resin surface. The epoxy resin surface was treated by corona discharge for 10 s to facilitate the formation of SAM through sur- face hydroxylation. TESPA SAM was obtained by dip- ping the epoxy resin into 2.5 mM TESPA monomer ethanol-water (V/V = 95:5) solution for 5 min at room temperature. The substrate was dried with nitrogen gas and cured at 120°C for 20 min. Then, a Sn-PdII colloidal solution was used as a catalyst precursor [22], which was prepared via precise control of sequential hydrolysis of PdII species according to the hydrolysis mechanism of PdII salts in a chloride-rich aqueous solution. The elec- troless deposition bath was prepared according to recent study [23]. X-ray photoelectron spectroscopy (XPS) was performed to investigate the elemental composition of surface by using ULVAC PHI-5600 spectrometer (Ulvac Technologies, Inc., Methuen, MA, USA). The adhesion strength between ELD copper film and TESPA SAM- coated epoxy resin substrate was investigated by T-peel test using an autograph S-100 apparatus (Shimadzu Cor- poration, Kyoto, Japan). Results and discussion TESPA was synthesized by the reaction of cyanuric chloride, 3-aminopropyltriethoxy silane (APTES), and NaSH according to the strategy described in the Figure 1. The stirring tetrahydrofuran (THF) solution of cyanuric chloride (0.1 mol) was added with APTES (0.1 mol) over a period of 60 min. And then the reaction mixture was added with THF solution of triethylamine (0.12 mol) for 1-day reaction. After, the solvent was removed under vacuum to yield 6-(3-triethoxysilylpropyl)amino-1,3,5- triazine-2,4-dichloride. NaSH ethanol solution was added dropwise for 2-h reaction to the ethanol solution of the dichloride. After, the solvent was removed under vacuum