4-minute read - by Christine Middleton, March 29, 2023
A single microchip in your smartphone or laptop is made up of dozens of layers of circuitry. For the chip to work properly, all of those layers have to be aligned with nanometer-level precision.
Lithography systems – the machines that print microchip patterns on silicon wafers – try to make sure that each chip layer sits perfectly on top of the previous one. In deep ultraviolet (DUV) lithography systems such as those made by ASML, the pattern for each layer is encoded in light and transmitted to the wafer using a series of lenses. Those lenses are incredibly smooth, but they still have tiny imperfections that can slightly distort the pattern being printed.
If those distortions change at all from one layer to the next, then the layers don’t quite line up. That misalignment can negatively affect a chip’s performance. It can even stop the chip from working altogether – a situation that chipmakers desperately want to avoid.
When chipmakers measure misalignment on their wafers, they adjust their lithography systems to correct for it. But chipmakers are now able to detect subnanometer-scale errors that available systems aren't able to correct for – they simply can’t make such tiny adjustments.
ASML teamed up with ZEISS, our strategic partner and maker of lenses for our lithography systems, to develop a solution: an improved lens-adjustment system. The new hardware and software upgrades, which are now fully integrated into ASML’s TWINSCAN NXT:2100i, provide chipmakers with unprecedented correction capability.
