Ultralow-k dielectrics prepared by plasma-enhanced chemical vapor deposition

Abstract

Carbon-doped oxide materials (SiCOH films) with ultralow dielectric constants have been prepared by plasma-enhanced chemical vapor deposition (PECVD) from mixtures of SiCOH precursors with organic materials. The films have been characterized by Rutherford backscattering and forward recoil elastic scattering analysis, Fourier transform infrared spectroscopy and index of refraction measurements, and measurement of step heights in the films. The electrical properties of the films have been measured on metal–insulator–silicon structures. By proper choice of the precursor and deposition conditions, the dielectric constants of the SiCOH films can be reduced to values below 2.1, demonstrating the extendibility of PECVD-prepared carbon-doped oxides as the interconnect dielectrics for future generation of very large scale integrated chips.

Low and Ultralow Dielectric Constant Films Prepared by Plasma‐enhanced Chemical Vapor Deposition

“…Different groups have investigated the properties of such fi lms and associated deposition process dependencies [41][42][43][44][45]. We have demonstrated that it is possible to extend this family of dielectrics to k values as low as 2.0 [46][47][48], thereby providing a path for the extendibility of using these fi lms in interconnects of future generations of the Si technology.…”

“…As mentioned above, in order to reduce further the dielectric constant of SiCOH fi lms in a controlled way the fi lms have to be prepared as a multiphase structure, using an organic porogen together with the SiCOH precursor in the plasma [46]. It was shown that the lowest achievable dielectric constant in pSiCOH fi lms depends on the organic precursor used [47,48], as illustrated in Figure 1.17 [56]. The dielectric constant of the fi lms deposited from TMCTS with the Por1 organic precursor reached a minimum value of 2.4 when deposited at a relatively low Por1/TMCTS ratio.…”

“…The removal of the porogen can be done by annealing the fi lms at 400-430°C in an inert ambient [46][47][48], or using e-beam or UV irradiation. The latter two techniques are much faster than the thermal anneal, can enhance the cross-linking in the cured fi lms and improve their mechanical properties [54,55].…”

“…(The CH notation refl ects the atomic compositions of the phase but not its stoichiometry.) Ultralow-k porous SiCOH (pSiCOH) fi lms can be prepared as a dual-phase SiCOH-CH material using the same PECVD method as described above and adding a hydrocarbon porogen (Por), as the CH precursor, to the SiCOH precursor feed to the reactor [46][47][48]53].…”

Influence of Substrate Materials on Deposition of Plasma-polymerized SiO:CH Particles

“…Silica materials with organic functional groups (SiO:CH) has attracted much attention because of its hydrophobicity, flexible bonding states, and low dielectric constant for the applications such as water-repellent surfaces [1][2], gas-barrier coatings [3][4], and insulating layers in microelectronic devices [5][6]. These properties can be improved when the SiO:CH films have microstructures with appropriate size and shapes.…”