The Life Estimator is accessible via the www.donaldson.com website.

Problem: Fabs want to know expected filter life so that they can set up a preventive maintenance filter changeout schedule. Otherwise, the only indicator that the filter is at capacity is disaster - yield loss, or worse, a hazed lens. Rather than take chances with million-dollar fab equipment, most fabricators opt to change out the filters at regular intervals. Depending on the mix of contaminants, the interval may be anywhere from 6 to 60 months. However, without knowing the particular mix of acids, bases and condensable organics, lifetime
expectancy is not accurately defined. The Life Estimator lets the user plug in contaminant levels specific to their own Fab and obtain a reasonable filter life estimate.

Solution: In the Life Estimator screen for example, the user first selects which ASML tool he has (XT, AT, or PAS). The Life Estimator then identifies which Donaldson filter that tool uses and the airflow it requires. When the user fills in specific levels of acids, bases and condensable
organics, the Life Estimator automatically calculates an estimated number of months recommended between filter change-outs. To use the Life Estimator, fabricators can go to the Donaldson website and click to register for a password.

Applications: The Life Estimator program is based on Donaldson lab data obtained under controlled conditions. The Life Estimator does not guarantee a specific filter life length because it can't calculate the effect of the occasional event (such as spilled ammonia), a change in the contaminant mix over time, or other unanticipated conditions.

Platform: Donaldson chemiadsorptive LITHOGUARD filters remove more than 99% of the ammonia, sulfur dioxide, photo-resist solvents (PGME, ethyl lactate, etc) and other VOC's generated by the semiconductor fabrication process.

Availability: January 2005 onwards.