ALTA® 4700DP Mask Writer
The Applied ALTA 4700DP Mask Patterning system is a fifth-generation DUV laser mask pattern generation system—extending the capabilities of the production-proven ALTA 4700 platform.
The ALTA 4700DP system provides cost-effective patterning of binary masks and phase shifting masks (PSM), supporting fast turnaround and shortened design cycles. High NA optics and a DUV laser produce the sharply focused beams needed to write photomask patterns with high resolution and tight dimensional control. Improved stage control enhances pattern placement accuracy, enabling precise matching between the masks in a set.
A new, highly integrated software-based data path running on a large array of high-speed processors enables the tool to pattern masks 10% to 50% faster than before. Pattern preparation and mask printing are performed in parallel, reducing overhead time in a high volume production environment.
The second-level alignment system provides the tight overlay needed to produce advanced PSM masks, which are used in greater numbers as wafer lithography is pushed to its limits. The non-exposing alignment light uses the same optical path as the exposure beam, avoiding baseline offsets and ensuring stable production performance.
The ALTA 4700DP uses multi-pass writing to enhance lithography quality, with a finer address grid enabled by the new data path. The 4-pass mode is used for the most demanding masks, while the high throughput 2-pass mode shortens the write time for less critical layers. Integrated software features can be used to improve global linewidth uniformity by compensating for pattern density-dependent errors and process-footprint errors.
The reliable printing engine combined with a minimal contact mask handling system results in very high yield. Also standard on the ALTA 4700DP is SECS/GEM, allowing communications between the system and the fab host, and enabling automation of the printing process.