Apr 03, 2014

A Jump in EUV Resist Sensitivity?

posted by Bryon Moyer

There was an interesting presentation that happened towards the end of SPIE Litho – it seemed to catch the audience off guard, and I frankly went away with the sense that there was some confusion in the room.

The presentation discussed an experiment that was done at Osaka University as part of the overall effort to optimize EUV exposure. It all relates to this seemingly inviolate triumvirate of “RLS”: resolution, LWR (line-width roughness), and sensitivity. Improvements within these three have to come at the expense of something within these three – they form a zero-sum game.

Normally, you expose the photoresist through the mask for the entire length of the exposure. The photons create acid where they interact with the resist, and this acid provides for the selective removal of resist material during development.

This experiment changed that. The exposure was broken into two steps:

  • A short exposure through the mask
  • After 10-15 minutes, then, with no mask, just a flood of UV across the entire wafer.

The first exposure seemed to create some acid, but mostly “sensitized” the photoresist (and I frankly didn’t come away understanding what that “sensitizing” meant from a chemical standpoint). The strange thing then was that flooding with the second exposure created the normal amount of acid only in the sensitized area.

This provided about 9 times the prior sensitivity, with no apparent tradeoff in LWR or resolution.

Note that no special resists were used; these were the same resists as are currently being used.

I didn’t get the sense that they had a real handle on what the underlying mechanisms were, and it was surprising to the audience. Assuming the data are correct, it’s certainly an interesting result. We’ll have to see if anything further comes of it, or if it goes the way of cold fusion…

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Apr 02, 2014

More MEMS Microphone Options

posted by Bryon Moyer

Everything’s going HD these days, and audio is no exception. That means that everything in the audio chain, from microphone to speaker, has to step up its game.

Akustica announced their first HD microphone in late 2012; they recently announced some new additions to the family.

And once again, packaging demonstrates that it refuses to be taken for granted with microphones. This is illustrated in two different aspects of the new Akustica offerings.

First is the notion of where the port goes. Port location makes a difference in the acoustics, but it also impacts designers that want more flexibility in locating and mounting the mics on very small boards like those inside phones. This is even truer given that multiple mics are becoming the rule for noise cancellation and other reasons.

So sometimes a designer wants to use a top-ported mic; sometimes a bottom-ported one. The thing is, apparently the audio software strongly prefers that the microphones be identical (or close to it). Changing the porting can screw that up, either resulting in tougher software or less placement flexibility for the designer.

So Akustica has announced matched top- and bottom-ported microphones. The idea is that you can use either one and they’ll still be close to “identical” (±1%). They accomplish the matching with a combination of tight manufacturing tolerances and a calibration step at test. Both the MEMS element itself and the accompanying ASIC are optimized.

The second package impact – and die strategy – has to do with the package size. With most every IC or sensor, smaller is always better (ignoring price). Not so with microphones. Given more space, you can do a two-die solution, optimizing MEMS and ASIC separately. You also have more cavity room in the package, which is important for sound quality.

So, while they’ve announced their matched high-performance HD mics, they also announced what they say is the smallest microphone around, in a 2x3 mm2 package. It is said to have good performance, but does compromise somewhat from the larger devices to achieve the smaller size.

You can read more about these in their announcement.

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Apr 01, 2014

EUV Blasts through 100 W

posted by Bryon Moyer

The EUV barrier has been broken.

And I found out right on the heels of yesterday’s EUV update – but too late to get it into that piece. Remember the issue with the misalignment of the laser? That happened when bringing the system back up from a power upgrade. Well, there’s more to it than most of us realized.

While the power upgrade was officially for 30 W publicly, they had had a breakthrough and were privately hoping for a lot more. They just didn’t want to say anything about it until they knew it would work; there have already been far too many expectations set and then missed with this technology. And the timing with SPIE Litho would have been perfect – what an amazing opportunity for a surprise announcement. But the glitch during bring-up messed all that up. The PR folks must have been going nuts.

But here’s the bottom line: the 30 W was a lowball goal. Once they got the system up and running again, they were able to push things to see how far they could get. And they got as high as 108 W!! This gets us past that magical 100-W barrier.

As I mentioned in yesterday’s piece, we don’t usually rush to press with breathless news, but this seems pretty big, given that it’s what so many folks have been waiting for. There’s been no formal announcement yet, but my source (who wishes to remain anonymous) said that the team’s excitement is beyond measure.

More details as they unfoold…

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