No abstract

Electron beam doping processes in the damageless region and at room temperature were investigated before annealing. In the three-layer system of layer 3/layer 2/layer 1, the impurity sheet (layer 2) was sandwiched between two semiconductor wafers. The surface of layer 3 was irradiated with electron beams of 750 keV and 7 MeV. Interstitials of displaced atoms in the overlayer, which were introduced by irradiation, migrated to the surface of the semiconductors. These interstitials diffused rapidly at the surface with a very large surface diffusivity of ∼10-5 cm2· s-1. The diffusion process was observed using an atomic force microscope (AFM). Impurity concentrations in the surface layer during irradiation were found to be on the order of matrix atom concentration. Electron irradiation produced a number of self-interstitials that migrated with large surface diffusivities at the surface. Diffusion was enhanced due to the kick-out mechanism at the interface of the system and in the depth direction of the semiconductors.

ABSTACT Among the variety of dual damascene (DD) processes, the via-first approach has drawn much attention because of its reduced process steps and improved photolithography process window. The via-first process requires a layer of via-fill material to be applied beneath the photoresist layer. The primary function of this via-fill material is to act as an etch-block at the base of the vias to prevent over-etching and punch-through of the bottom barrier layer during the trench-etch process. However, such materials also help to planarize the substrate and may limit back reflection from the substrate as well, helping to control the critical dimension (CD) of the printed features. Based on this understanding, our research efforts have been focused on the advancement of DD-applicable bottom antireflective coatings (BARCs). A series of novel plananzing DUV BARCs with full-via-fill properties and enhanced etching selectivity to resists have been developed. They showed good full-fill, void-free performance in O.2Oim vias having an aspect ratio of five(5), also sufficient top coverage i.e., enough coating thickness, low surface variation, and little thickness bias of isolated-via (1:10) area versus dense-via (1:1) area. The resist sidewall profiles with feature sizes less than O.2Oim indicated that there was good compatibility of the BARCs with the resists. The thin film etching selectivity to commercial resists was about I .2: 1 under an HBr/02 atmosphere. A study of the BARCs described in this report allows further discussion of the impact of pattern density, feature size, and processing conditions on BARC coating performance.

This paper examined effects of sports practice on patterns of color fields, limits of peripheral movement perception, and visual acuity field by comparing varsity ball players and non-varsity control groups. The first study measured extent of color fields and limits of horizontal and vertical meridians for peripheral movement perception of 139 college students. The second study tested visual acuity fields of female and male basketball players and female and male controls. The first study indicated that athletes had wider limits for horizontal movement perception, while the non-athletes had better vertical movement perception limits. Basketball players demonstrated color fields and limits for peripheral movement perception superior to those of soccer players. In the second study, athletes did not have any wider visual acuity fields than non-athletes, but their movement-perception limits were significantly wider than those of non-athletes.

No abstract