Porous ultralow-k films are required by the microelectronics industry as interlayer dielectrics for 65 nm technologies and below. These porous insulating films can be deposited by plasma-enhanced chemical vapor deposition using a porogen approach. It consists of the codeposition of a matrix precursor and a sacrificial organic porogen, and then on a post-treatment to remove the organic porogen phase and create porosity in the film. In this work, an e-beam assisted thermal curing was compared to an ultraviolet-assisted thermal curing. Basic film properties such as k, film shrinkage, porosity, pore size, and pore size distribution were evaluated. NMR and Fourier transform infrared analyses were used to study the chemical modifications induced by the post-treatment. These analyses show that the post-treatment impact depends on the radiation used. Both treatments lead to a removal of terminal nonbridging bonds such as Si-OH, Si-H, and Si-CH 3 and can contribute to a subsequent formation of Si-O-Si crosslinks. Both treatments remove methyls from Si-CH 3 , but the e-beam induces a Si-H bond increase while the UV bulb used decreases the Si-H contribution. The cross-linking improvement induces an increase of Young's modulus, the elastic properties being mainly correlated to the Si-O-Si volumic bond concentration in the film.A new challenge for the semiconductor industry is to reach the low permittivity ͑k Ͻ 2.4͒ required for advanced interconnections by ITRS for sub-65 nm technology nodes. Porosity introduction in an a-SiOC:H matrix ͑written down SiOCH in the following͒ is the main research field investigated. The porogen approach is one way to produce porous materials using plasma-enhanced chemical vapor deposition ͑PECVD͒. It consists of the codeposition of a matrix precursor and a sacrificial organic porogen. 1-3 After deposition, porogens are eliminated in subsequent steps, leaving their initial sites empty and creating porosity. To decrease the porogen removal duration and temperature, thermally assisted processes can be used, with UV irradiation or electronic bombardment ͑e-beam͒. 4-6 Many works were performed on the impact of e-beam or UV curing on an insulating SiOCH matrix as a hardener treatment. In this case, the main results reported are an increase of mechanical properties, the exact mechanism being not fully understood. 7-9 Yoda et al. reported also the use of e-beam curing to enhance the mechanical properties of porous films. 10 In this study, an e-beam thermally assisted curing treatment used to remove porogens is compared to a UV thermally assisted one. Basic film properties after deposition and curing are described: investigations with physicochemical analyses, porosity measurements by ellipsometry coupled with solvent adsorption, and grazingincidence small-angle x-ray scattering ͑GISAXS͒. Mechanical and electrical studies were carried out to better understand the impact of each porogen removal treatment on the chemical structure of the dielectric films. After a brief presentation of the experimental tec...

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