David M. Johns

Timing compensation for an excimer laser solid-state pulsed power module (SSPPM)

For certain applications, it is critical to minimize variations in the (throughput) timing between trigger and the output pulse of a magnetic modulator. A circuit is described that maintains a relatively constant delay over a large operating voltage range (600-1150 V) and temperature range (25 /spl deg/C-65 /spl deg/C) range, The circuit operates by sampling the charging voltage and magnetic switch temperature just prior to the start switch trigger. Those parameters are then used to calculate the appropriate amount of delay to add into the low-level trigger chain to ensure that the delay stays constant over the voltage and temperature operating range. Although other approaches can be conceived and implemented, this particular design is relatively simple and inexpensive and meets the desired performance goals. Data presented show that the ideal correction function is nonlinear in nature and, as a result, simple linear approximations are limited in their ability to minimize the timing variations. Improvements to the original circuit use a multiple, piece-wise, linear approach in order to obtain better performance. The results are that an initial timing variation of almost 3 /spl mu/s has been reduced to a total variation of less than 100 ns.

Lifetime and reliability data of commercial excimer laser power systems modules

Since 1996, CYMER has manufactured over 1500 excimer lasers for the application of integrated circuit photolithography. Because reliability and cost of operation (CoO) are critical in the semiconductor industry, it is extremely important to quantify these parameters for the laser and each of the primary modules. Lifetime and reliability data for the initial generation of solid state pulsed power module (SSPPM) units are presented from a number of sources, including more than 750 laser systems in the field in addition to a number of in-house module verification systems. Highly accelerated life test (HALT) experiments have also been implemented at CYMER to help quantify the design margins of these modules with respect to operating parameters such as temperature and voltage. In addition, results are updated from an experiment involving testing of a SSPPM to over 50B shots where the unit was characterized at several intervals in an attempt to detect any potential signs of degradation which might limit the operational lifetime or cause the unit to fail. To date, no such indications of degradation have been measured. The paper compares actual reliability and lifetime data from these various sources compared to the original lifetime estimates.