Showing papers by "Ivan Sondi published in 2000"

Encapsulation of Nanosized Silica by in Situ Polymerization of tert-Butyl Acrylate Monomer†

Abstract: Stable dispersions of nanosilica ranging in size between 8 and 11 nm were coated with tert-butyl acrylate polymer by in situ polymerization of monomer adsorbed on the particles in 2-propanol. The system was developed for use in the encapsulated inorganic resist technology. To achieve a high coating efficiency, silica was first modified with the 3-(trimethoxysilyl)propylmethacrylate (MPS) coupling agent at two different degrees of grafting. The presence of the bound MPS agent and of the polymer at the silica surface was determined by the attenuated total reflection infrared spectroscopy, while the amounts bound were assessed by the thermogravimetric analysis. Under studied conditions, the encapsulation efficiency was governed by the degree of MPS grafting and by the initial concentration of the monomer. Finally, the dissolution rate of these particles in aqueous base, a key parameter in photoresist application, was drastically reduced with increasing amount of grafted tert-butyl acrylate polymer at the sil...

Preparation of aminodextran-CdS nanoparticle complexes and biologically active antibody-aminodextran-CdS nanoparticle conjugates

Abstract: Stable aqueous dispersions consisting of CdS nanoparticles having modal diameters, ranging between 2 and 8 nm, were prepared with amino-derivatized polysaccharides (aminodextrans, hence abbreviated as Amdex) as the stabilizing agents. The size, stability, and luminescence intensity of such dispersions were shown to be dependent on the types of the cadmium salts and aminodextrans used, as well as on the reactant concentrations. Specifically, it was demonstrated that the degree of substitution of amino groups in the aminodextran molecules greatly affected the properties of the dispersions; i.e., with higher degree of substitution, smaller CdS particles and higher luminescence intensity were achieved. It was also shown that the Amdex−CdS nanoparticle complexes could be activated and conjugated with antibody by conventional means. Molecular weight ranges of the Amdex and their complexes with CdS nanoparticles and the purity of antibody−Amdex−CdS nanoparticle conjugates were determined by polyacrylamide gel el...

Encapsulated inorganic resist technology

Abstract: Resolution in traditional single layer organic resists has been limited by the inability to image at aspect ratios (resist height to image width) of much greater than 3:1. Unless plasma etch selectivity increases several fold (an unlikely event with organic based resists) single layer resist chemistry will cease to be practical at sub-100-nm resolution. Multilayer resist schemes offer the capability of increased aspect ratio, but they add to the process complexity and cost. Encapsulated inorganic materials as resist components will be ultimately capable of sub-100-nm resolution with sufficient plasma etch selectivity. The encapsulated inorganic resist technology (EIRT) resist will act as a single layer hard mask compatible with existing resist processing steps. Material evaluation showed that encapsulated inorganic materials have properties compatible with current resist technology. Lithographic evaluations have been performed with electron beam, and with 248 nm and 157 nm projection systems. It was shown that 150-nm imaging is possible with resists having high inorganic material content. In all cases the EIRT resists have shown lithographic performance equivalent to control resists containing no SiO 2 . Reactive ion etch (RIE) etch rates in oxygen and chlorine plasmas are significantly reduced for resists containing SiO 2 nanoparticles as compared to a commercial resist providing a proof of concept that EIRT resists can dramatically improved plasma etch rates.

Novel semiconductor nanoparticles for analysis of blood cell populations

Abstract: A semiconductor nanoparticle for use in analysis of biological samples is described. This semiconductor nanoparticle is composed of an aminodextran which is bound to at least one nanoparticle of the formula (X Y)n wherein X is selected from the group comprising Cd?2+, Hg2+?, and Zn2+ and combinations thereof; and Y is selected from the group comprising S?2-, Se2- and Te2-? and combinations thereof; and n = approximately 50 to 1000. Also provided are methods of making these semiconductor nanoparticles and methods of making conjugates composed of these semiconductor nanoparticles linked to ligands. Also described are uses for the conjugates in a variety of biological assays.

Nouvelles nanoparticules aux fins de l'analyse de populations de globules sanguins

Abstract: Cette invention a trait a une nanoparticule a semi-conducteur, utilisable pour analyser des prelevements biologiques. Cette nanoparticule se compose d'aminodextrane lie a au moins une nanoparticule correspondant a la formule (X Y)n. Dans cette formule X est selectionne dans le groupe constitue par Cd?2+, Hg2+ et Zn2+? et leurs combinaisons, tandis que Y est selectionne dans le groupe constitue par S?2-, Se2- et Te2-? et leurs combinaisons, la valeur de n s'echelonnant, approximativement, de 50 a 1000. L'invention porte egalement sur des procedes de production de ces particules a semi-conducteur ainsi que sur des procedes de production de conjugats constitues de ces nanoparticules a semi-conducteur liees a des ligands. Elle concerne, de surcroit, l'utilisation qui est faite de ces conjugats dans divers titrages biologiques.