When last we talked with Cymer, they had just announced their PrePulse technology that gets more of the energy out of the droplets they blast with a laser. They had achieved 50-W output.
That’s only half-way to what’s needed for production, and, at the time, it was an “open-loop” result. That is, not something that could be repeated over and over in a production setting.
In my discussion with them at Semicon West, they now have 50 W working on a sustained, closed-loop basis (for five hours). And they have achieved 90 W in short open-loop bursts.
But there are lots of other characteristics besides simple power that are important for production viability.
- Duty cycle: after they run the system for a while, things heat up. Literally. For that and a number of reasons, they have to give the machine a break or else the power rolls off. Right now they’re running at 40% duty cycle; they’re working to get that (closer) to 100%.
- Dose stability: their five-hour runs have resulted in 90% of dice having less than 1% dose error.
- Availability: if the machine is always down or needs lots of maintenance, well, that’s a problem. They’re now claiming 70% up-time.
- Collector longevity: at some point, having been bombarded with pulses, the collector will start to lose reflectivity. It would then need to be replaced – meaning downtime and cost. So far they say that they’ve gone above 30 billion pulses without seeing any reflectivity degradation.
Meanwhile, efforts to increase power depend on three separate factors: input power, “conversion” efficiency – how much of that input power gets released from a pulsed droplet, and collector efficiency.
Their PrePulse technology has satisfied them on the second item; their efforts at this point are in increasing the input power (they’ve demonstrated up to 17 kW) and improving collector efficiency. This takes place in what they call their “HVM II” model, which is being integrated now.
