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Mask Aligner/Aligner

Wikipedia:[1]

Maskless lithography utilizes methods that directly transfer the information onto the substrate, without utilizing an intermediate static mask, i.e. photomask that is directly replicated. In microlithography typically radiation transfer casts an image of a time constant mask onto a photosensitive emulsion (or photoresist).
The concept takes advantage of high speed or parallel manipulation technologies that have been enabled by large and cheap available computing capacity, which is not an issue with the standard approach that decouples a slow, but precise structuring process for writing a mask from a fast and highly parallel copy process to achieve high replication throughputs as demanded for in industrial microstructuring.

Traditional photolithography calls for the fabrication or purchase of a photomask and the use of a stepper or mask aligner to transfer the CAD-pattern onto the resist-covered wafer or plate. At this point in time, the well-established photomask process is indeed the only feasible way for high volume manufacturing of sub-micron sized design features.
Another photolithography technique available which constitutes the perfect tool for many other applications: Maskless photolithography. In maskless photolithography the pattern is exposed directly onto the substrate surface with the help of a spatial light modulator (SLM) – which serves essentially as a programmable mask. The system takes your design file and simply “writes” the pattern onto the resist-covered substrate.
Direct-write process puts you in a position to skip the entire time-consuming and expensive photomask process and all it involves: Instead, you can redesign your CAD-drawing (again and again, if necessary) and immediately re-expose the pattern.

Reference :

Mohammed Ziauddin ; Abdel-Hamid I. Mourad ; Saud A. Khashan

In this study, cost effective measures are taken in selecting each component in building the system.
Main components that took larger share of the cost are the XY linear stage, software, stepper motors and drivers, and power supply.
In this study, the maskless lithography system is developed based on UV laser writing tool and simultaneously moving XY linear stage

Kunal Pharas 1979-University of Louisville

This project aims at designing and fabricating a programmable mask for a direct write lithography system which can achieve higher throughput at a reasonable cost for the semiconductor industry in the future.
The device has apertures of different sizes that can be used as programmable masks by opening and closing the shutters over them.
The optical image of the developed photoresist that was exposed through the apertures resembles almost identical feature size and linewidth measurement of the pattern exposed

K. Venkatakrishnan, B.K.A. Ngoi, P. Stanley, L.E.N. Lim, B. Tan & N.R. Sivakumar

Currently they are fabricated by a lithographic process, which is very expensive and time-consuming since it is a multi-step process. These issues can be addressed by fabricating photomasks by direct femtosecond laser writing, which is a single-step process and comparatively cheaper and faster than lithography.
In this paper they discuss our investigations on the effect of two types of laser writing techniques, namely front- and rear-side laser writing, with regard to the feature size and the edge quality of a feature.

MILES P. LIM, XIAOFEI GUO, EVA L. GRUNBLATT, GARRETT M. CLIFTON, AYDA N. GONZALEZ, AND CHRISTOPHER N. LAFRATTA

A new method of hybrid photolithography, Laser Augmented Microlithographic Patterning (LAMP), is described in which direct laser writing is used to define additional features to those made with an inexpensive transparency mask.
This combination of direct laser writing and conventional UV lithography compensates for the drawbacks of each method, and enables high-resolution prototypes to be created, tested, and modified quickly.

Steffen Diez, Heidelberg Instruments Mikrotechnik GmbH (Germany)

The essential goal for fast prototyping of microstructures is to reduce the cycle time. Conventional methods up to now consist of creating designs with CAD software, then fabricating or purchasing a Photomask, and finally using a mask aligner to transfer the pattern to the photoresist.
The new Maskless Aligner (MLA) enables to expose the pattern directly without fabricating a mask, which results in a significantly shorter prototyping cycle. To achieve this short prototyping cycle, the MLA has been improved in many aspects compared to other direct-write lithography solutions: exposure speed, user interface, ease of operation, and flexibility.