To enable the continued scaling of integrated circuits, the semiconductor industry faces ongoing struggles to implement better low‐dielectric‐constant (low‐k) materials within the interconnect system. One of the biggest challenges to integrating new dielectrics is overcoming the low‐k death curve—that is, the fatal falloff in mechanical properties associated with the low material densities required to achieve low k values. It is shown that amorphous hydrogenated boron carbide (a‐BC:H) films exhibit Young's modulus (E) values between two and ten times greater than those of state‐of‐the‐art Si‐based dielectric materials across a wide range of k values. In particular, optimized a‐BC:H films with moderate k values in the range of 3–4, in addition to possessing outstanding stiffness (E ≈ 100–150 GPa), simultaneously exhibit excellent electrical properties (leakage current of <10–8 A cm–2 at 2 MV cm–1 and breakdown voltage of >5 MV cm–1). Films in this range also demonstrate resistance to Cu diffusion to at least 600 °C, as well as chemical stability and etch properties suitable for low‐k diffusion barrier/etch stop applications.

New multipass optical lithography patterning methods needed to print features for future &lt;10 nm technologies will demand an increasingly complex combination of hardmasks, antireflection coatings, spacers, and etch stopping materials with distinct yet complementary properties. Finding the right mix, however, has proven particularly challenging given that the materials most commonly used are drawn from a limited set of Si- and C-based solids comprising Si, C, O, N, and H. To understand and maximize the limits of this composition space, the authors have performed a combinatorial survey of the dry etch characteristics for the Si-C-O-N-H system with the goal of understanding material composition–etch interactions and identifying material subclasses with distinct etch properties. Over 50 thin films sampling Si-C-O-N-H composition space were surveyed using two fluorinated etches commonly utilized for selective patterning of SiO2 and a-SiN:H dielectrics (CHF3 and CF4/O2, respectively). It was found that the incorporation of oxygen in a-SiN:H allowed for significant tuning of the etch rate of a-SiON:H materials relative to SiO2. Additionally, increasing hydrogen content and nanoporosity significantly increased the etch rate of the various dielectric materials independent of the Si, C, O, and N content. The influence of carbon depended on whether it was incorporated as terminal organic groups, where it resulted in increased etch rates, or directly within the network of the material, where it resulted in decreased etch rates. Silicon- and carbon-rich materials exhibited very low etch rates in both etches and were found to have the most distinct and potentially complementary etch properties relative to SiO2 and a-SiN:H. Accordingly, a-C:H, a-Si:H, and a-SiC:H merit further examination as hardmask or spacer materials in future multipass patterning processes.

International audienceIn a parallel investigation, the etch characteristics of materials within the Si-CO -N-H system were surveyed using two common fluorinated plasma etches used to etch SiO 2 interlayer dielectrics and SiN:H etch stop layers (CHF 3 and CF 4 /O 2 , respectively) with the goal of identifying new materials or " colors " to assist in the simplification of advanced multi-pass optical lithography. In this study, we investigat

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