Effects of photoresist polymer molecular weight on line-edge roughness and its metrology probed with Monte Carlo simulations
A fast 2D/3D resist dissolution algorithm based on the critical ionization model is used to quantify line-edge roughness and determine its relation to resist polymer molecular weight, the end-to-end distance and the radius of gyration, keeping acid effects off (i.e., minimal). The algorithm permits also simulations of line-edge roughness metrology by examining the effects of SEM measurement box length.
A fast path-based method for 3-D resist development simulation
Abstract A three-dimensional (3-D) remaining resist profile often needs to be estimated and examined especially for nanoscale feature. However, conventional methods, such as the cell removal method and fast marching method, require intensive computation, and therefore are too time-consuming to be employed for large patterns such as a mask or an iterative procedure such as proximity effect correction (PEC). In this paper, a new method for 3-D resist development simulation has been developed for fast and accurate simulation of simple patterns such as lines and rectangles. It employs the concept of “development paths” to model the development process. In order to reduce the simulation time, each path is examined individually without a time-consuming iterative procedure which is adopted by conventional methods. An adaptive scheme has also been incorporated into the proposed simulation method, which further reduces the simulation time without sacrificing simulation accuracy substantially. The simulation results show that the proposed method achieves resist profiles well matched with those by conventional methods, even for more general patterns, but reducing simulation time by orders of magnitude, and the speed-up is larger for a larger pattern. Also, the accuracy of the proposed method has been verified experimentally.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.