Eric P. Guyer

Short-ranged structural rearrangement and enhancement of mechanical properties of organosilicate glasses induced by ultraviolet radiation

The short-ranged bonding structure of organosilicate glasses can vary to a great extent and is directly linked to the mechanical properties of the thin film material. The combined action of ultraviolet (UV) radiation and thermal activation is shown to generate a pronounced rearrangement in the bonding structure of thin organosilicate glass films involving no significant compositional change or film densification. Nuclear magnetic resonance spectroscopy indicates loss of –OH groups and an increase of the degree of cross-linking of the organosilicate matrix for UV-treated films. Fourier transform infrared spectroscopy shows a pronounced enhancement of the Si–O–Si network bond structure, indicating the formation of more energetically stable silica bonds. Investigation with x-ray reflectivity and ellipsometric porosimetry indicated only minor film densification. As a consequence, the mechanical properties of microporous organosilicate dielectric films are substantially enhanced while preserving the organosili...

Electrical technique for monitoring crack growth in thin-film fracture mechanics specimens

An accurate and reliable electrical technique for continuous monitoring of crack growth in fracture specimens containing technologically relevant thin-film device structures has been developed. Both adhesive and cohesive crack growth measurements are reported using a SiO 2 passivation layer and a conducting titanium film deposited on the side face of fracture specimens. Crack velocity measurements approaching 10 −12 m/s were achieved, representing nearly an order of magnitude improvement over commonly used compliance-based techniques. The technique may be particularly useful for elucidating near threshold crack velocity behavior, which is important for thin-film reliability.

Effect of CMP slurry environments on subcritical crack growth in ultra low-k dielectric materials

The success of next generation interconnects relies to a large degree on the integration of low-k dielectric (LKD) materials capable of surviving chemical mechanical planarization (CMP). However, little is currently understood about the effect CMP slurry environments have on the reliability of these advanced dielectrics. Accordingly, the focus of this research was to characterize and model the effect of CMP solution chemistry on adhesion and subcritical debond growth in thin-film structures containing LKD materials for future generation devices.

Adhesion between template materials and UV-cured nanoimprint resists

The origins of defects in lithographic stencils fabricated by the UV-cure nanoimprint technique include fundamental surface interactions between template and resist in addition to the presence of particles and contaminants. Repeated, molecularly clean separations of the template from the newly cured resist is a requirement, yet rather little is understood about the separation process or underlying interfacial physics and chemistry. We have investigated the chemical and physical interactions of several model acrylate nanoimprint resist formulations cured in contact with clean and release-treated quartz surfaces, then separated from them. The results show that fracture energies are resist formulation-dependent, that the resist-release layer systems studied are not chemically stable and that release process is more complex than simple fracture at a glass-organic interface.

Accelerated crack growth of nanoporous low-k glasses in CMP slurry environments

Considerable efforts have been directed at integrating nanoporous low dielectric constant (LKD) materials into the interconnect structures of high-density integrated circuits. The reliable fabrication of devices containing these fragile materials is, however, a significant technological challenge due to their high propensity for mechanical failure during all levels of processing and subsequent packaging operations in which they are subjected to mechanical loads in the presence of aggressive aqueous environments, such as chemical mechanical planarization (CMP). Here we demonstrate the significant effect of CMP solution chemistry on interfacial adhesion and crack growth rates in nanoporous LKD thin-films as well as lithographically patterned structures containing copper and LKDs. A new mechanism of accelerated cracking in H/sub 2/O/sub 2/ environments is revealed.

Effect of porosity on reducing cohesive strength and accelerating crack growth in ultra low-k thin-films [IC interconnect applications]

The reliable fabrication of interconnects containing nanoporous low dielectric constant (LKD) films has proven to be a significant technological challenge. The LKDs are brittle in nature and susceptible to stress corrosion cracking in reactive aqueous environments. Moreover, nearly all levels of processing involve subjecting these extremely fragile materials to mechanical loads in the presence of harsh aqueous solutions, such as chemical mechanical planarization (CMP). Here we demonstrate how controlled volume fractions of nanometer scale porosity reduces the cohesive strength of LKDs and significantly accelerates the rate of crack growth in both simulated and commercial CMP solutions.