Masakazu Endo

Effective IP protection method of mask data using OASIS format

We have been developing intellectual properties (IP) protection software using OASIS format. In the Photomask Technology 2004 we presented that by taking advantage of repetition presentation of OASIS, it becomes possible to express arrayed patterns without any generation of new cells, which also brings less overhead and further compaction of the result file. As a result, we could rebuild the hierarchy without cell generation and reduce the output file size. In this paper, additionally we have applied a unique compression function CBLOCK defined in OASIS format. CBLOCK can compress any part of OASIS file. The experimental results show that there are no redundant cells generated and the file size has become approximately 20 times smaller than conventional methods.

Evaluation of mask manufacturing efficiency using mask data rank information

The photomask cost is becoming one of the challenging issues in the semiconductor industry, as the cost of photomasks has been rising year by year. ASET started Mask D2I (Mask Design, Drawing and Inspection Technology) project with the sponsorship from the NEDO (New Energy and Industrial Technology Development Organization) in 2006 for the purpose of the mask cost reduction. In earlier papers[1-5], we introduced the idea of photomask data prioritization method which is referred to as Mask Data Rank (MDR). We have built our software system to convert Design Intent (DI) to MDR with cooperation of STARC. Then we showed the results of experiments with mask data provided by semiconductor companies. In this paper we show the additional report of mask inspection experiments using real photomasks. Then we show the evaluation results about mask drawing time reduction using MDR flow. Finally we introduce detailed algorithm to extract design intent from analog circuits.

Development of a design intent extraction flow for mask manufacturing

The cost of photomasks has been rising year by year as the process node gets finer and the mask cost is becoming one of the headaches in the semiconductor industry. For the purpose of the mask cost reduction, ASET started Mask D2I (Mask Design, Drawing and Inspection Technology) project in 2006. In earlier papers[1-4], we introduced the idea of photomask data prioritization method which is referred to as Mask Data Rank (MDR). We have built our software system to convert Design Intent (DI) to MDR with cooperation of STARC. Then we showed the results of preliminary experiments with mask data provided by STARC. In this paper we explain the software mechanism of design intent extraction flow. Then we show the experimental results with actual chip data in three semiconductor companies and address the related issues. Finally we introduce a new idea to extract design intent from analog circuits.

From GDSII to OASIS : Practical support tools for data processing flow transition

OASIS format has begun to be accepted in the field of mask data processing gradually. Major EDA venders have announced their support of OASIS format and new versions of EDA tools which can handle with OASIS files have been shipped one by one. Still, there are great difficulties to convert all the data processing flow from old GDSII to new OASIS. One of the major issues is a problem of verification. Since all the tools have not been completely stable and reliable, there should be a method to verify whether the data is converted to OASIS without any problems. In addition to that, the integrity of the OASIS files itself have to be checked. In general, OASIS has two aspects for the mask industry. One is a role as a new replacement of GDSII. The other is OASIS.VSB, which is a unified format defined for the description of fractured EB data. SII NanoTechnology has been developing a new software package called SmartOASIS. SmartOASIS provides lots of practical functions to enable easy transition of data processing flow from conventional GDSII or EB formats to OASIS.