| Electroless plating method is widely used in microelectronics, radio-electronics, and aerospace techniques. It allows us to obtain uniformly thick coatings on the articles of any profiles of metallic, dielectric and semi-conducting materials. Electroless plating method is showing advantages in the fabrication of metal interconnect of integrated circuit and in the development of new substrates for biochip. However, partly attributed to the low durability of its coating, the application of this extremely cheap process is limited. Consequently, finding a way to combine high quality coating with electroless plating method becomes one of the provocative objectives. In this dissertation, the topic of electroless plating on self-assembled monolayer (SAM) and its applications were brought forward and studied by means of some physical chemistry techniques, such as X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Ultraviolet spectroscopy (UV), etc. The major contributions include the following aspects:1. Preparation of mercapto groups' functionalized glass substrateThe conventional technique for the preparation of SAM on glass substrate was improved by using solvent extracting. In general, a non-polar solvent, such as benzene, was used to extract thoroughly the physisorption of silane on glass substrate after reaction with Mercaptopropytrimethoxysilane (MPTS) solution, and then the extractions using solvents with increased polarity, such as acetone and doubly distilled water, were performed in turn to induce the outward orientations of mercapto groups during the diffusion and reformation of silane on the glass surface. The XPS and Auger electron spectroscopy (AES) results showed that a glass substrate functionalized ideally with mercapto groups was obtained.2. Electroless plating on self-assembled monolayerElectroless silver plating on the MPTS self-assembled monolayer modified glass substrate was conducted with the following optimized prescription: 4.0g/L of AgNO3, 10g/L of glucose, 15g/L of NaOH, sufficient NH4OH to dissolve Ag precipitates, 100mL/L of ethanol and 4mL/L ofsaturated I2 aqueous solution. The electroless plating rate was found to be more than 3.2 μm per hour, and a solid and shining silver film with good adherence to substrate was prepared. Electroless copper plating on glass through successive pretreatment with MPTS silane and colloidal silver was also investigated. The optimum composition of the plating bath was as follows: 24 g/L of CuSO4·5H2O, 39 g/L of potassium sodium tartrate, KNaC4H4O6·4H2O, 16 ml/L of formaldehyde (37%), and 10 mg/L of 2,2′-dipyridyl. The pH value was adjusted to be ~13.3 with sodium hydroxide, NaOH. XPS and AFM results indicated that colloids formed a condensed monolayer of catalytic film on MPTS SAM via the formation of S-Ag bonds, which guaranteed a faster electroless plating rate, a better adherence of copper coating with glass substrate and a longer life-time of plating solution than conventional palladium catalyzing method. In a word, electroless copper plating on MPTS SAM was a cheap technique and implied its important application in electroless plating industry.3. Electroless copper plating through microcontact printingPolyurethane (PU) based on polypropylene glycol (PPG 2000) and toluene diisocyanate (TDI) using 3,3'-dichloride-4, 4'-methylenedianiline (MOCA) and trimethylol propane (TMP) as the crosslinker was synthesized with the optimum prescription of 1 mol of PPG, 3 mols of TDI and 0.9 mol of crosslinker composed of 5 parts MOCA and 1 parts of TMP. The synthesized PU elastomer surface exhibited good affinity with acetonitrile and ethanol, and the corresponding advancing contact angles were examined to be less than 3 and 4 degrees, respectively. It was proved from mechanical properties examination tests that the synthesized PU elastomer had the advantage over polydimethylsiloxane (PDMS) elastomer and became an alternative material for molecular stamps.The above-mentioned po...
|
PDF Full Text Request