The EU-funded HoLiSTEP project aims to unlock the potential of sub-wavelength Holographic Lithography (HL), presenting it as a disruptive and enabling lithography technology. HL overcomes the limitations of PL by enabling the creation of high-resolution 3D topographies while significantly reducing the cost of high-resolution integrated circuit (IC) producti
Objective
To achieve ever-decreasing dimensions and higher resolutions of circuit elements, projection lithography (PL) continues to grow in complexity and cost for manufacturers. However, it is limited to producing two-dimensional images on flat surfaces. The extension to three-dimensional imaging is constrained by the trade-off between focus depth and resolution. Advanced, cost-efficient solutions for fabricating wafer-scale 3D components are therefore essential.
The HoLiSTEP project aims to unlock the potential of sub-wavelength holographic lithography (HL) as a powerful and disruptive lithographic technology. HL is designed to overcome the limitations of PL, enabling the production of novel 3D topographies with high resolution, while significantly reducing the cost of producing high-resolution integrated circuits.
An industrial prototype operating at 345 nm with 200 nm resolution will be developed and validated in an operational environment. To achieve this, several advancements in holographic stepper subcomponents are required: a UV fibre-based laser with 20 W output power at 345 nm and a coherence length of 1.5 m; an alignment system with 25 nm overlay precision; an adaptive optical system with a correction precision of 1/20λ; and software modules incorporating vector diffraction models.
The energy consumption of HL technology is drastically reduced compared to PL, due to the low power consumption of the laser and the ability to produce complex structures in a single exposure. Furthermore, HL images are less sensitive to mask defects, eliminating the need for frequent mask replacements and the use of toxic materials. Additionally, holographic masks act as projection optics, removing the requirement for complex optical systems.
The HL prototype will be verified for 3D patterning of MEMS, MOEMS, and micro-optical components, demonstrating superior resolution, greater flexibility in 3D printing, and reduced costs. By enabling a broader range of companies to produce novel high-resolution 2D and 3D images more affordably, HoLiSTEP is expected to have a transformative positive impact on the environment, economy, and society.