Saturation of front propagation in a reaction-diffusion process describing plasma damage in porous low-k materials

We propose a three-component reaction-diffusion system yielding an asymptotic logarithmic time-dependence for a moving interface. This is naturally related to a Stefan-problem for which both one-sided Dirichlet-type and von Neumann-type boundary conditions are considered. We integrate the dependence of the interface motion on diffusion and reaction parameters and we observe a change from transport behavior and interface motion \sim t^1/2 to logarithmic behavior \sim ln t as a function of time. We apply our theoretical findings to the propagation of carbon depletion in porous dielectrics exposed to a low temperature plasma. This diffusion saturation is reached after about 1 minute in typical experimental situations of plasma damage in microelectronic fabrication. We predict the general dependencies on porosity and reaction rates.Comment: Accepted for publication in Phys. Rev.

Effect of energetic ions on plasma damage of porous SiCOH low-k materials

Plasma damage of SiCOH low-k films in an oxygen plasma is studied using a transformer coupled plasma reactor. The concentration of oxygen atoms and O2+ ions is varied by using three different conditions: (1) bottom power only, (2) bottom and top power, and (3) top power only. After plasma exposure, the low-k samples are characterized by various experimental techniques. It is shown that the ion bombardment induced by the bottom power minimizes the plasma damage by increasing the recombination coefficient of oxygen radicals. Contrary to the expectations, the densification of the top surface by ion radiation was limited. The increase in the recombination coefficient is mainly provided by modification of the pore wall surface and creation of chemically active sites stimulating the recombination of oxygen atoms. The results show that a reduction in plasma damage can be achieved without sealing of low-k top surface.status: publishe

High and hyper NA immersion lithography using advanced patterning film APF (TM)

The objective of this work is to enable the manufacturing of features with most aggressive pitches available to date using APF as a strippable hard mask (HM). Essential for the capability of printing small and in particular dense features is the control of optical reflections during exposure. This is achieved through control of the optical parameters of the used films. The considered optical parameters are the complex reflection coefficient ((n) over tilde =n-ik) and thickness. The angle of incidence of the exposing light when using high or hyper NA (numerical aperture) lithography is no longer negligible. As a consequence the optimum film thickness corresponding to the lowest reflection varies with the pitch of the features being imaged In this paper we discuss the results based on a Hyper-NA simulation illustrating the complexity of such at? optimization process. Furthermore we discuss various High-NA simulations and corresponding physical experimental work confirming the validity of this approach

The small-gap technique: understanding an ion shading method for plasma-surface interactions study

Link to presentation: https://imec-events.be/UserFiles/76/File/Presentations/S3/S3_PESM2010_JFdM.pdfstatus: publishe

Metal hard-Mask Based Double Patterning for 22nm and Beyond

In this paper, metal hard-ma.sk-based patterning schemes are proposed to pattern 30/30 nm line/space structures and 40-nm contact holes at 80 nm pitch. Various litho and etch approaches are compared and discussed.status: publishe