Thickness dependence of elastic modulus and hardness of on-wafer low-k ultrathin polytetrafluoroethylene films

Fast assembly of bio-inspired nanocomposite films

“…In contrast to Wang et al, 33 E r does not follow the expected U-shaped curve. They investigated Teflon films in the thickness range of 48.1-1141 nm and found among the above-mentioned U-shaped curve type that, when the film thickness is less than 500 nm, the modulus increases sharply as the film thickness decreases.…”

“…25,28,33 The increase in hardness as the indentation depth approaches the film/substrate interface is attributed to the influence of the hard substrate, while the initial decrease in hardness is related to surface effects, e.g., surface roughness. Saha and Nix 24 found that soft films on hard substrates accommodate all the plastic deformation, while the substrates begin to deform only when the indenter is very close to the film/substrate interface.…”

Evaluation of carbon-doped low-k multilayer structure by nanoindentation

“…They recently proved capable to detect the effect of porosity [19], resolve the impact of interface adhesion, thickness and influence of layered architecture on mechanical parameters of ultra-thin low-k films [20][21][22], and clarify the mechanical stability of mesoporous structures [23]. Interestingly, using this technique, Liou and Pretzer [24] evaluated thermal stresses, thermal expansion and concluded on bond-conversion from Si-H to Si-O in hydrogen silsesquioxane low-k films due to variations of curing temperature, while thorough study of indentation fracture by Volinsky et al [25] led to the new criterion of spontaneous cracking of low-k films.…”

Mechanical Characterization of Black Diamond (Low-k) Structures for 3D Integrated Circuit and Packaging Applications

“…The initial decrease of properties as the indentation displacement increases is observed during nanoindentation of very thin films [49]. The averaged values of properties in minima plateau region are considered to be the real properties of the films and, in the present study, these values are used to define the properties of each film as shown Fig.…”

“…Extensive simulation studies show that, the effective elastic modulus of a film experiences greater substrate effect than the hardness value [44]. BD -100 nm film shows significantly higher elastic modulus (E=16.48 GPa) when compared to higher thickness BD films and it is expected due to molecular restructuring in very thin BD films (≤100 nm), since the elastic modulus is an intrinsic material property, which largely depends on interatomic or molecular bonds [49]. Hence the higher elastic modulus of BD-100 nm film is probably expected due to stronger molecular bonding between organic (-CH3) and inorganic (Si-O) constituents.…”