Empirical models for chemical vapor deposition of SiO2 from tetraethylorthosilicate (TEOS) and O-3 have been proposed using one- and two-precursor models of the surface rate limited reaction kinetics. In the one-precursor model, considered here, the wafer surface is described by a Robin boundary condition, Phi = Phi(sat) - <(alpha)over tilde>(partial derivative Phi/partial derivative (n) over tilde), where Phi is the concentration of the gas phase generated reactant precursor, Phi(sat) is its saturation concentration, (n) over tilde is a normal vector pointing outward from the diffusion region (into the wafer substrate), and d is a surface reaction kinetics parameter. The validity of the diffusion model approximation for transport in the continuum and near continuum regimes dictates that Phi be a solution to the Laplace equation in the interior of a diffusion region "closed up" to form a polygon. The horizontal top side of the polygon represents the macroscopic free flow boundary layer. The Robin (wafer) boundary forms the base of a rectangle (flat Robin boundary) or five sides of an octagon (entrenched Robin boundary). Closure of the geometrical boundary (diffusion region) results from the abstract construction of outer vertical polygonal sides [homogeneous Neumann boundaries where (partial derivative Phi/partial derivative (n) over tilde) = 0]. The closed-up polygon forms a rectangle in the case of a flat wafer surface and an octagon in the case of a wafer surface with a trench. For the rectangle, it suffices to model adsorption along the base (flat wafer substrate) with a constant <(alpha)over tilde>. For the entrenched wafer surface, a phenomenological curvature dependence in <(alpha)over tilde> has been previously proposed to arise due to the introduction of corners and edges via the trench. We propose a spatial dependence in <(alpha)over tilde> which unfolds from the transformation properties of the Robin boundary condition when an infinite rectangle (flat wafer geometry) is conformally mapped into an octagon (entrenched wafer geometry). The boundary conditions for the transformed wafer surface are then used in a Green's function boundary integral equation formulation of the problem. Numerical solutions, presented for the diffusion current, the surface reaction kinetics parameter, <(alpha)over tilde>, and the deposition concentration, Phi, prove to be consistent with a conformal (uniform) film profile.