We have evaluated a unified mask pattern data format named "OASIS.MASK"1 and a unified job deck format
named "MALY"<sup>2</sup> for mask tools as the input data formats of the inspection tool using the mask data and the photomask
produced with the 65nm design rule. The data conversion time and the data volume for the inspection data files were
evaluated by comparing with the results for using the native EB data and the native job deck data. The inspection speed
and the defect number of the inspection tool were also evaluated with the actual inspection tool. We have confirmed that
there is no large issue in applying OASIS.MASK and MALY to the input data formats of the inspection tool and they
can become the common intermediate format in our MDP flow. The detail of evaluation results will be mainly
introduced in this paper.
Over the last 5 years, Japanese consortium, Semiconductor Leading Edge Technologies Inc. (Selete), lead the way in developing unified mask data format. Specification of the format was released as OASIS.VSB and registered to SEMI standard, P44. It is expected that using OASIS.VSB would reduce TAT and improve efficient usage of data infrastructure. OASIS.VSB has advantages for mask data preparation since OASIS.VSB is based on OASIS<sup>TM</sup> (SEMI P39) and OASIS compliant software is already commercially available. Although fundamental evaluation of OASIS.VSB have been made by Selete on technical feasibility with VSB mask writers, its performance and advantage of data handling improvement is still controversial. We have been evaluating OASIS.VSB in order to estimate the impact of data handling improvement at mask manufacturer. Figure 1 shows that OASIS.VSB has good compression ratio compared to certain VSB mask data format. Although compression ratio partly depends on data and conversion software, OASIS.VSB is about 0.7 times as small as VSB data format on weighted basis average. Furthermore, we have confirmed by simulation that OASIS.VSB can hardly affect shot count and writing time.
Unification of mask data format by OASIS.VSB can realize flexible mask data preparation (MDP) and reduce a cost of data storage. To achieve further TAT reduction, it is necessary to apply OASIS.VSB to not only mask writing data but other mask making processes such as die to database inspection and mask rule check (MRC).
As patterns on photomasks are getting more complex due to RET technologies, mask rule check (MRC) has become an essential process before manufacturing photomasks. Design rule check (DRC) tools in the EDA field can be applied for MRC. However, photomask data has unique characteristics different from IC design, which causes many problems when handling photomask data in the same way as the design data.
In this paper, we introduce a novel MRC tool, SmartMRC, which has been developed by SII NanoTechnology in order to solve these problems and show the experimental results performed by DNP. We have achieved high performance of data processing by optimizing the software engine to make the best use of mask data's characteristics. The experimental results show that only a little difference has been seen in calculation time for reversed pattern data compared to non-reversed data. Furthermore, the MRC tool can deal with various types of photomask data and Jobdec in the same transparent way by reading them directly without any intermediate data conversion, which helps to reduce the overhead time. Lastly it has been proven that result OASIS files are several times smaller than GDS files.
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.
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.
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.