High resolution, low cost laser lithography using a Blu-ray optical head assembly

We present a novel, cost-effective laser lithography system capable of producing periodic and non-periodic patterns with sub-micrometre feature sizes and periodicities. The optical head assembly of a Blu-ray disc recorder containing a 405 nm semiconductor diode laser and 0.85 NA objective lens was mounted on a motion stage and it was used to expose silicon samples covered with a mixture of SU-8 photoresist and photoinitiating chemicals. Experiments were carried out to demonstrate the lithographic capabilities of the system, and a smallest feature size of 450 nm was obtained. Grating structures were fabricated in order to demonstrate system capabilities.

► Novel photolithography technique using Blu-ray optical head. ► Resolution achieved is in the order of laser wavelength. ► Resolution is comparable to commercial direct laser write equipment. ► Cost effective novel technique.