Mask data preparation (MDP) for modern mask manufacturing becomes a complex process because many kinds of EB data formats are used in mask makers and EB data files continue to become bigger by the application of RET. Therefore we developed a unified mask pattern data format named "OASIS.VSB<sup>1</sup>" and a job deck format named "MALY<sup>2</sup>" for Variable-Shaped-Beam (VSB) EB writers. OASIS.VSB is the mask pattern data format based on OASIS<sup>TM 3</sup> (Open Artwork System Interchange Standard) released as a successive format to GDSII by SEMI. We defined restrictions on OASIS for VSB EB writers to input OASIS.VSB data directly to VSB EB writers just like the native EB data. OASIS.VSB specification and MALY specification have been disclosed to the public and will become a SEMI standard in the near future. We started to promote the spread activities of OASIS.VSB and MALY. For practical use of OASIS.VSB and MALY, we are discussing the infrastructure system of MDP processing using OASIS.VSB and MALY with mask makers, VSB EB makers, and device makers. We are also discussing the tools for the infrastructure system with EDA vendors. The infrastructure system will enable TAT, the man-hour, and the cost in MDP to be reduced. In this paper, we propose the plan of the infrastructure system of MDP processing using OASIS.VSB and MALY as an application of OASIS.VSB and MALY.
We have developed a unified mask data format named “OASIS.VSB” for Variable-Shaped-Beam (VSB) EB writers. OASIS.VSB is the mask data format based on OASIS released as a successive format to GDSII by SEMI. We have defined restrictions on OASIS for VSB EB writers to input OASIS.VSB data directly to VSB EB writers just like the native EB data. We confirmed there was no large problem in OASIS.VSB as the unified mask data format through the evaluation results. The latest version of OASIS.VSB specification has been disclosed to the public in 2005.
The diversification of mask making equipment in modern mask manufacturing has led to a large variety of different mask writing and inspection formats. Dispositioning the equipment and managing the data flow has turned into a challenging task. The data volumes of individual files used in the manufacture of modern integrated circuits have become unmanageable using established data format specifications. Several trends explain this: size, content and complexity of the designs are growing; the application of RET increases the vertex counts; complex data preparation flows post tape-out result in a large number of intermediate representations of the data. In addition assembly steps are introduced prior to mask making for leveling critical parameters. Despite the continuous effort to improve the performance of the individual tools that handle the data, is has become apparent that enhancements to the entire flow are necessary to gain efficiency. One concept suggested is the unification of the mask data representation: establishing a common format that can be accepted by all tools. This facilitates a streamlining of data prep flows to eliminate processing overhead and repeated execution of similar functions. OASIS, the new stream format developed under the sponsorship of SEMI, has the necessary features to full-fill the role of a common format in mask manufacturing. The paper describes the implementation of OASIS as a common intermediate format in the mask data preparation flow as well as its usage with additional restrictions as a common Variable-Shaped-Beam mask writer format. The benefits are illustrated with experimental results. Different implementation scenarios are discussed.
We have developed a unified mask data format named “OASIS.NEO<sup>1</sup>” for Variable-Shaped-Beam (VSB) EB writers as enhancement of unified mask data format named “NEO<sup>2</sup>”. OASIS.NEO is a pattern data format based on OASIS<sup>TM3</sup> released as GDSII replacement by SEMI. We have developed OASIS.NEO for practical use of unified mask data formats in mask data preparation (MDP) flow. For practical use, it is necessary to input OASIS.NEO data directly to VSB EB writers just like the native EB data. So we have defined restrictions on OASIS for VSB EB writers referring the restrictions in NEO based on GDSII named “GDSII.NEO<sup>4</sup>”. In this paper we proposed the specification of OASIS.NEO.
Mask data preparation (MDP) is a complicated process because many kinds of EB data files and jobdeck data files are used in mask manufacturers and EB data files continue to become bigger. Therefore we have developed unified mask data formats for Variable-Shaped-Beam (VSB) EB writers with efficient data compaction. The unified mask data formats are composed of a pattern data format for EB writers named "NEO" and a layout format named "MALY". We released NEO and MALY on April 2003. To evaluate NEO and MALY, we have made a prototype system of MDP such as a converter from design data to NEO/MALY and converters from NEO/MALY to each EB data. We have evaluated about functions and performance of the MDP flow using real design data in device manufacturers. As a result, some improvements in NEO and MALY were achieved and we have revised the specification of NEO and MALY as the final version. We have confirmed that NEO and MALY can be used for a set of unified mask data formats among VSB EB writers and can reduce complexity of mask data handling in mask manufacturers. They will be put to practical use in MDP flow.
The shortening of electron beam settling time is important for the shortening of writing time of variable-shaped beam (VSB) writers.
The settling time is the time until the electron beam is deflected to a desired position, and is settled. In the case of electrostatic deflector, the electron beam is deflected in proportion to the voltage to which the amount of deflections is supplied. The Digital-Analog converter and Amplifier (DAC/Amp) circuit supplies voltage required for deflector and, in order to shorten a settling time; it is necessary to accelerate operation of a DAC/Amp circuit. Especially, the amplifier operation speed should be accelerated.
The performances required of amplifier are high-speed operation and high-voltage operation. The key technology for high speed and high voltage operation of amplifier is the development of high speed, high voltage operation transistor. Although these two performances are the relation of a trade-off, the transistor that has attained our required performances dose not exists. For this reason, we started from joint development of the transistor, which had attained the required performances. Furthermore, we developed the trial peace amplifier using the developed transistor and evaluated. In addition to these results, we will also report the result of the throughput evaluation using the pattern for supposing the 65nm node device pattern.
Mask data preparation is a complicated process because many kinds of EB data files and jobdeck data files are used in mask manufacturers and EB data files continue to become bigger. Therefore we have started to develop new mask data format with efficient data compaction and unification among Variable-Shaped-Beam (VSB) EB mask writers. We have proposed the unified mask pattern data format for EB writers named "NEO"<sup>1</sup> in the 22nd annual BACUS symposium. We have proposed the unified mask layout format named "MALY" 2 and the high-compression data processing system3 for NEO in Photomask Japan 2003, too. Then we have decided to develop an enhanced mask data preparation system using NEO<sup>4</sup> and MALY<sup>5</sup>. This system has common MDP functions not to be related to each EB writer. That would be effective in reducing mask data handling cost. In this paper we introduce the abstract of NEO and MALY and new mask data preparation system using NEO and MALY.
It depends for the writing time of variable shaped electron-beam (VSB) writing system on the number of writing shots. For shortening of writing time, it is most effective to reduce the number of shots. However, Resolution Enhancement Technologies (RET), such as OPC and PSM, make the VSB shot number increase explosively, in addition to reduction of LSI pattern size, and worsens the writing throughput. This is a serious problem for VSB mask writer, and the improvement of a writing throughput is required. In order to solve this problem, we inquired towards diversifying beam shape only from a rectangle.
First, we investigated about the curtailment effect of the number of shots by trapezoid aperture adoption. Some latest VSB writer has adopted a triangle shaped aperture to compose the slanting figure in the LSI pattern efficiently. We investigated the efficiency of forming the slanting figure with trapezoid or parallelogram apertures compared with initial triangle aperture shot number. As the result of that, shown in Fig.1, we obtained the result that the shots number was reduced into 50% or more compared with initial triangle shots number. And, we examined a possibility of uniting and applying the character projection (CP) technique, which is adopted as EB direct writing (DW), to mask writing. Since pattern size is, for example, 4 times larger in the case of mask writing compared with the case of EBDW, the area that can extract a common CP pattern out from LSI patterns at mask writing is smaller than EBDW. Then, we extracted CP aperture pattern from cell library data for logic LSI. We obtained the result, shown in Fig.2, that the shot number that was used CP aperture was reduced into about 35% compared with initial VSB shots number. However, the arrangement number of aperture has restriction, and if the arrangement number decreases, the curtailment rate of the shots number will fall. These two techniques are fundamentally effective in curtailment of writing shots number. Furthermore, we will discuss with the possibility of applying these techniques to mask writing and with some problems to solve for the application of these techniques.
Mask data preparation is a complicated process because many kinds of pattern files and jobdeck files flow into mask manufacturers. This situation has a significant impact on data preparation operations especially in mask manufacturers. In this paper, we propose a solution to this problem: use of unified mask data formats for EB writers and a model of data preparation flow from a device manufacturer to an EB writer. The unified formats consist of pattern data format named "NEO", and mask layout format named "MALY".
NEO is a stream format which retains upper compatibility to GDSII and has higher compression rate than GDSII. NEO is intended to be a general input format of Variable-Shaped-Beam (VSB) mask writers in principle, not particularly designed for any specific equipment or software. Data conversion process between mask writers being taken into account, NEO requires some constraints for VSB mask writers, such as removal of overlapping figures. Due to many differences in jobdeck syntax and functions among mask writers, it is a complicated task to edit or modify a jobdeck, and convert it into another format. MALY is a text-based format whose purpose is to standardize mask layout information among mask writers. This unification of mask layout information optimized for EB writers is expected to reduce workload of mask data preparation significantly. Besides the information described in MALY, some other information specific to the target EB writer, such as drawing parameters, has to be prepared separately. This paper illustrates a model of data flow and benefits of using these unified formats. The format and the data flow are effective in reducing data handling cost, providing flexible data handling solution. Applying the handling flow using NEO and MALY would result in reducing the load on mask manufacturers. Moreover, device manufacturers would be freed from the need to specify the mask writer to be used when ordering masks to mask manufacturers.
Recently as the node size gets smaller into deep sub-micron, both chip designers and mask manufacturers have faced great problems as follows: (1) Explosion of the data size; (2) Further data complexity due to OPC or PSM; (3) Increasing numbers of data formats. Since these problems directly lead to the increase of the mask costs, we have thought that they need to be overcome from the viewpoint of data processing as well. Selete have made a proposal of a next generation EB handling format, called 'NEO', in order to cope with these issues. The greatest feature of NEO is its compaction capability of the data description and it is expected that the chip data size could be reduced far smaller than in any other existing EB formats. We have been working on the NEO project in cooperation with Selete and developed a new system 'GDS2NEO', which converts the conventional layout data described in GDSII to the NEO-formatted data. We also investigated the compaction efficiency of NEO with several sets of actual layout data using GDS2NEO. As the result, we have proved that NEO has an excellent efficiency of data compaction and GDS2NEO has achieved a satisfactory performance of data conversion. In this paper we present the concept of NEO format, the data processing flow and the basic algorithm of GDS2NEO, the experimental results and the future plans.
Proc. SPIE. 4889, 22nd Annual BACUS Symposium on Photomask Technology
KEYWORDS: Data compression, Data modeling, Manufacturing, Data processing, Software development, Photomasks, Optical proximity correction, Data conversion, Electronic design automation, Standards development
Mask data preparation (MDP) systems are becoming more and more complicated due to increasing demand for higher resolution, and more commonly adopted technique of optical proximity correction (OPC). Conventionally, as a standard format to describe mask patterns, GDSII has been widely used in the EDA field as well as in the mask production field. These days, however, GDSII is revealing its disadvantage in terms of efficiency in data compaction. On the other hand, mask pattern data in a variety of formats, including GDSII, are flowing into mask manufacturers, and this is making their process extremely complicated.
In this paper, we propose a unified format, tentatively named "GDSII-NEO." GDSII-NEO is designed to retain GDSII upper compatibility in consideration of the utilization of existing GDSII data and to have several times higher compression rate than GDSII. GDSII-NEO can be seen as a multi-purpose format used widely in the EDA and mask field. An intended use, among others, of this format is to describe the pattern data fed into Electron Beam (EB) mask writers.