Comments on: Advanced Lithography 2012 – Day 4 https://lithoguru.com/life/?p=239 Musings of a Gentleman Scientist Mon, 30 Nov -001 00:00:00 +0000 hourly 1 https://wordpress.org/?v=6.4.5 By: David https://lithoguru.com/life/?p=239#comment-14007 Mon, 30 Nov -0001 00:00:00 +0000 #comment-14007 I’m old enough to remember when I-line lithography was considered impossible (difficult source, absorption too high in the resist and optical glass), KrF was too risky (ditto), ArF will never happen (ditto).

F2 and high-index immersion didn’t happen; sometimes they don’t (we maybe gave up too quickly, with EUV just around the corner).

I remember seeing an early ArF laser, finding it hard to believe that such a bomb would be allowed in a wafer fab – and, even it is was, it would destroy the optics…

And so we are now with EUV.

This is a remarkable industry – maybe the most remarkable industry – heroic efforts from many people, under incredible pressure, with unrealistic deadlines. And when they succeed, ho-hum – 2nm overlay, down from 200nm twenty years ago. But why isn’t the overlay 1nm, or 0.1nm?

As with the previous wavelength changes, the last pieces of the EUV jigsaw to be developed are the source and resist – too late and too expensive, but maybe just in time.

Or maybe not, this time – physics may finally intervene – we shall see next year.

]]> By: daBow https://lithoguru.com/life/?p=239#comment-14033 Mon, 30 Nov -0001 00:00:00 +0000 #comment-14033 What makes EUV different from previous wavelength changes is it is ionizing, so it is not just photons, there are also charges, i.e., photoelectrons and secondary electrons, involved, adding more randomness to the LER issue.

]]> By: Fred Chen https://lithoguru.com/life/?p=239#comment-14041 Mon, 30 Nov -0001 00:00:00 +0000 #comment-14041 We submitted a paper to this year’s SPIE (8326-96). It was shown that avoiding shot noise at 20 nm would require >47 mJ/cm2 dose of EUV, which makes the common expectation of 30 mJ/cm2 or less very misguided.

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