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Chemical composition, pore structure and mechanical properties of porous organosilicate low-k films with terminal and bridging organic groups are studied. It is shown that BTMSE based low-k films with alkyl bridge between the Si atoms have non-uniform pore structure with internal voids (ink-bottle like pores) while the films with terminal alkyl groups have pores with cylindrical shape. All studied spin-on deposited films have better mechanical properties than PECVD films with similar chemical composition and porosity. The best mechanical properties showed alkyl bridged low-k films. Moreover, the Young's modulus increases with BTMSE content because of higher concentration of bridging bonds. Porous organosilicate glasses (OSG) have many different applications such as catalysts, adsorbents, trapping agents, drug delivery agents, stationary phases in chromatography and chemical sensors. 1One of the most important applications of porous OSG films is related to interconnects in advanced ULSI (ultra large-scale integration) devices where they are used as insulators with low dielectric constant. Modern ICs can be made very compact, incorporating up to several billions transistors and other electronic components in an area of about 1 cm 2 . All transistors and other IC components have to be electrically interconnected to provide the proper functionality. The width of the conducting lines that connect different transistors in a circuit is becoming very small; in 2008, it dropped below 100 nm, and now is of the order of a few tens of nm. In parallel, the interconnect delay is becoming an increasing limitation factor of the overall signal propagation delay. The low dielectric constant materials are needed to reduce capacitance (C) between the metal (Cu) conductors. Together with low resistivity (R) of metal wires, low-k materials improve ULSI device performance by decreasing RC delay, cross talk noise and power consumption in interconnects.2 Different types of organosilicate films deposited by plasma enhanced chemical vapor deposition (PECVD) and spin-on glass (SOG) technology have been developed during the last 20 years. Using of appropriate precursors allows to control the chemical composition and porosity of these films. PECVD is currently the method of choice in microelectronic industry because this technique is easily integrated in the existing device manufacturing process.3 PECVD precursors (normally different types of organosilanes) are transferred to the reaction chamber where Si wafer is located on a heated pedestal. Quality of the deposited films depends on plasma characteristics and pedestal temperature. In the modern interconnect technology, the dielectric layer is deposited by PECVD and patterned first before the metal deposition using lithography and plasma etching. Lithography and plasma etching define the structure of interconnect wiring by forming certain patterns in the dielectric film. Then copper should fill the patterns in the dielectric film by superfilling electrodeposition and after chemicalmechanica...

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