As minimum feature size and pitch spacing further scale down, triple patterning lithography is a likely 193 nm extension along the paradigm of double patterning lithography for 14-nm technology node. Layout decomposition, which divides input layout into several masks to minimize the conflict and stitch numbers, is a crucial design step for double/triple patterning lithography. In this paper, we present a systematic study on triple patterning layout decomposition problem, which is shown to be NP-hard. Because of the NP-hardness, the runtime required to exactly solve it increases dramatically with the problem size. We first propose a set of graph division techniques to reduce the problem size. Then, we develop integer linear programming (ILP) to solve it. For large layouts, even with the graph-division techniques, ILP may still suffer from serious runtime overhead. To achieve better trade-off between runtime and performance, we present a novel semidefinite programming (SDP)-based algorithm. Followed by a mapping process, we can translate the SDP solutions into the final decomposition solutions. Experimental results show that the graph division can reduce runtime dramatically. In addition, SDP-based algorithm can achieve great speedup even compared with accelerated ILP, with very comparable results in terms of the stitch number and the conflict number.Index Terms-Graph division, integer linear programming (ILP), layout decomposition, semidefinite programming (SDP), triple patterning lithography (TPL).

Angiogenesis, or neovascularization, is known to play an important role in the neoplastic progression leading to metastasis. CD31 or Factor VIII-related antigen (F VIII RAg) immunohistochemistry (IHC), is widely used in experimental studies quantifing tumor neovascularization in immunocompromised animal models implanted with transformed human cell lines. Quantification, however, can be affected extensively by variations in the methodology used to measure vascularization including antibody selection, pretreatment with antigen retrieval and evaluation techniques. To examine this further, we examined the microvessel density and the intensity of microvascular staining among five different human tumor xenografts and a mouse syngeneic tumor using anti-CD31 and F VIII RAg IHC staining. Different antigen retrieval methods also were evaluated. Maximal retrieval of CD31 was achieved using 0.5 M Tris (pH 10) buffer, while maximum retrieval of F VIII RAg was achieved using 0.05% pepsin treatment of tissue sections. For each optimized retrieval condition, compared to F VIII RAg, anti-CD31 highlighted small vessels better. Furthermore, the microvessel density of CD31 was significantly greater than that of F VIII RAg decorated vessels (p < 0.001). The choice of antibody and antigen retrieval method has a significant affect on immunohistochemical findings when studying angiogenesis. One also must use caution when comparing studies in the literature that use different techniques and reagents.

A review of the history of working memory (WM) studies finds that the concept of WM evolved from short-term memory to a multi-component system. Comparison between contemporary WM models reveals: (1) consensus that the content of WM includes not only task-relevant information, but also task-irrelevant information; (2) consensus that WM consists of phonological and visuospatial components; (3) consensus that short-term memory storage is a function of WM; (4) disagreement as to whether an independent executive control is a necessary WM component; and (5) disagreement as to whether the control function is active or passive. Methods for measuring WM differed across studies with a preponderance of various dual-tasks; little psychometric work has been done on these measures. Correlational studies supported a close relationship between WM and measures of fluid intelligence and science achievement, but we found no experimental studies on the impact of WM training on science achievement. Finally we suggest how WM research findings may be applied to improve fluid intelligence and science achievement.

Double patterning lithography (DPL) is considered as a most likely solution for 32 nm/22 nm technology. In DPL, the layout patterns are decomposed into two masks (colors), and manufactured through two exposures and etch steps. If the spacing between two features (polygons) is less than certain minimum coloring distance, they have to be assigned opposite colors. However, a proper coloring is not always feasible because two neighboring patterns within the minimum distance may be in the same mask due to complex pattern configurations. In that case, a feature may need to be split into two parts to resolve the conflict, resulting in stitch insertion which causes yield loss due to overlay and line-end effect. While previous layout decomposition approaches perform coloring and splitting separately, in this paper, we propose a simultaneous conflict and stitch minimization algorithm with an integer linear programming (ILP) formulation. Since ILP is in class NP-hard, the algorithm includes three speed-up techniques: 1) grid merging; 2) independent component computation; and 3) layout partition. In addition, our algorithm can be extended to handle design rules such as overlap margin and minimum width for practical use as well as off-grid layout. Our approach can reduce 33% of stitches and remove conflicts by 87.6% compared with two phase greedy decomposition.

Electronic Beam Lithography (EBL) is an emerging maskless nanolithography technology which directly writes the desired circuit pattern into wafer using e-beam, thus it overcomes the diffraction limit of light in current optical lithography system. However, low throughput is its key technical hurdle. In conventional EBL system, each rectangle in the layout will be projected by one electronic shot, through a Variable Shaped Beam (VSB). This would be extremely slow. As an improved EBL technology, Character Projection(CP) shoots complex shapes, so called characters, by putting them into a pre-designed stencil to increase throughput. However, only a limited number of characters can be put on the stencil due to its area constraint. For those patterns not in the stencil, they still need to be written by VSB. A key problem is how to select an optimal set of characters and pack them on the CP stencil to minimize total processing time. In this paper, we investigate a new problem of EBL stencil design with overlapped characters. Different from previous works, besides selecting appropriate characters, their placements on the stencil are also optimized in our framework. Our experimental results show that compared to conventional stencil design methodology without overlapped characters, we are able to reduce total projection time by 51%.