ALTA® 4700plus Mask Patterning
The Applied ALTA 4700plus mask patterning system is a fourth-generation deep ultraviolet (DUV) laser mask pattern generation system, extending the capabilities of the production-proven ALTA 4700.
The ALTA 4700plus 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.
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 4700plus uses multi-pass writing to enhance lithography quality. The 4-pass mode is used for the most demanding masks, while the high throughput (HT) 2-pass mode shortens the write time for less critical layers. Applied Process Correction (APC) can be used to improve 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 4700plus is SECS/GEM, allowing communications between the system and the fab host, and enabling automation of the printing process.