The development is a step forward to the production of circuits using high-NA lithography and a path down to 2 and 1nm circuit definition.
IMEC used a 13.5nm wavelength source for interference or holographic lithographic imaging on metal-oxide resist from Inpria under high numerical aperture conditions. Interference between two optical sources can be used to define regular arrays of features – such as lines and spaces – without the use of complex optical systems or photomasks.
KMLabs Inc. (Boulder, Colo) is a manufacturer of ultrafast laser systems and is a partner in the AttoLab initiative with IMEC. KMLabs provided the laser source in a Lloyd's Mirror configuration on experiments on IMEC’s spectroscopy beamline. In this arrangement, light reflected from a mirror interferes with light directly emitted by the 13.5nm laser source, generating a finely detailed interference pattern suited for resist imaging.
The next step is to move the research on to 300mm-diameter wafers. It will be used to provide industry with patterned wafers for process development before the first high-NA (0.55) lithography system from ASML becomes available. That is the EXE5000.
"The high-flux laser source of KMLabs was used at a record small wavelength of 13.5nm, emitting a series of attosecond (10^18s) pulses that reaches the photoresist with a pulse duration that is a few femtoseconds (10^15s) in width," said John Petersen, principal scientist at IMEC and SPIE Fellow.
He added that current generation 0.33NA EUV lithography scanners are now being pushed to single-exposure limits.
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