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Electron beam direct write (EBDW) provides high resolution for device and technology development. A new variable shaped beam system with improved electron optics was introduced, which features the capability for the 32nm node. Because of the limited resolution of commercially available chemically amplified resists at this node, it is important to determine a stable and optimum resist process window. To compare a process window under different premises, a universally applicable and low error-prone method is needed. The isofocal dose method is investigated with regard to these properties for its use in EBDW. Experiments were performed on 50kV variable shaped electron beam direct writers using the new electron-optical column SB3050 DW (Vistec Electron Beam GmbH). Exposures are performed at different sites in Dresden (Fraunhofer CNT/Qimonda Dresden), Jena (Vistec) and Stuttgart (IMS Chips); also patterns are exposed on different layer stacks at one site. The strong need for a process window can be fulfilled by the isofocal dose method, which will be shown by contour plots.

The tendency to smaller feature sizes is continuing in the microelectronic industry. EBDW is a well introduced method for research and development of semiconductor devices. A tool architecture based on the variable-shaped beam (VSB) principle offers a significant throughput advantage compared to any Gaussian beam system. A VSB column with high resolution is presented in this paper which is capable of being applied down to the 32nm node and below. Starting with electron-optical simulations the major influences on the resolution are considered: i.e. coulomb interaction, geometrical and chromatic aberrations. State of the art dynamic corrections are applied to the main field deflector. However, the manufacturing accuracy has also to be taken into account. A well balanced design was necessary to ensure the manufacturability of the final lens. Knife edge measurements were executed to verify the resolution enhancement. Exposed resist patterns are the most important results with respect to their practical use in the semiconductor industry. Several resists, CAR as well as conventional ones, positive and negative resists were exposed to get a realistic impression regarding the resolution capability of the new column. It was possible to achieve 14nm single lines in HSQ resist.

If electron beam technology is used for direct writing on Si wafers (synonym EBDW) there have to be taken into account a number of specific issues concerning the layout data preparation differing considerably from those of mask writing. This is especially true because EBDW enables the most advanced technology levels which are in general one or two nodes ahead of the mainstream optical lithography. Consequently we will have to face up to additional challenges, such like high resolution and the corresponding CD - control parameters. In order to achieve acceptable turn around times the shaped beam writers have proven to be the tool of choice. To demonstrate this behind a practical background we describe our experiences collected during 300mm wafer exposures with a SB351/3050 tool installed at the Fraunhofer Center Nanoelectronic Technology (CNT) in Dresden/Germany. Appropriate solutions are presented showing how to execute such procedures like layout fracturing and Proximity Effect Correction (PEC) of high-density layouts on a Linux computing cluster. The CD accuracy of lines being of particular interest in connection with sub 50 nm patterns being analyzed and a new model-based method allowing the reduction of the before mentioned effect is evaluated. In any case, whether it is about short or time-consuming exposures, a precise forecast of the total processing time of the wafer in the e-beam exposure tool is of great importance. Practical findings from the use of a simulation tool specifically developed for this purpose are discussed in this paper.

E-beam direct writing, one node ahead of advanced optical lithography, can be a time and cost effective option for early device and technology development as well as for fast prototyping. Because of the device complexity only a variable-shaped e-beam writer combined with sensitive chemically amplified resists (CAR) can be considered for this approach. We evaluated various pCARs and nCARs of all major suppliers for our goal to structure DRAMs of the 50nm node using the Leica SB350 e-beam writer. The most promising samples were selected for a process optimization by variation of bake and development conditions. Finally, one resist of each tonality met the most of our specifications like dense lines and contact holes resolution, sensitivity and vacuum stability.

For 90nm node and beyond technology generations, one of the most critical challenges is how to meet the local CD uniformity (proximity) and global CD uniformity (GCDU) requirements within the exposure field. Both of them must be well controlled in the mask making process: (1) proximity effect and, (2) exposure pattern loading effect, or the so-called e-beam "fogging effect". In this paper, we report a method to improve our global CDU by means of a long range fogging compensation together with the Leica SB350 MW. This exposure tool is operated at 50keV and 1nm design grid. The proximity correction is done by the software - package "PROXECCO" from PDF Solutions. We have developed a unique correction method to reduce the fogging effect in dependency of the pattern density of the mask. This allows us to meet our customers’ CDU specifications for the 90nm node and beyond.

Modern wafer stepper generations are capable of realizinghigher circiut levels due to high-performance lenses in the WV region, but at the same time there is also the • necessity of designing assembly groups of the wafer stepper so that they meetthe requirements of a wide assortment range in modem device fabrication. Long years of practical experience in the use of steppers enabled Jenoptik to implement an new generation of wafer steppers, in whichparticular value was placed on the instrumental improvement of theparamemters:. interna] thermostatting/mininnim particle contamination— alignment accuracy - useful depth of focus. . I . INTRODUCTION Jenoptik JENA GmbEI looks back to a nearly 20-year-experience in the denel opment and producti on of photol ithography eiivs. During thisperiod about 500 photorepeaters and 230 wafer steppers were produced and on the basis of intergcrvernmentil agreements, mainly suppliedto the Comecon countries . Main trading partner of photol ithography