MicroWriter ML 3 - The future of photolithography
Conventional photolithography is a process that uses a mask aligner to transfer patterns from a chromium-glass mask onto a substrate coated with a photoresist layer. This process has several limitations, including:
- Overlay accuracy is limited by the fixed pattern on the mask.
- Alignment with randomly distributed samples (often needed for research of 2D materials) is difficult because the pattern positions on the mask cannot be changed.
- Backside alignment is complex.
- Flexible or non-flat substrates are difficult to work with.
The MicroWriter ML 3 systems offer a solution to these obstacles. The system holds the design patterns in software and uses computer-controlled optics to project the exposure patterns directly onto the photoresist. With this flexibility plus a simple and intuitive Windows user interface, the overlay procedure (with an overlay accuracy down to +/- 0.5 µm) can be easily achieved (Fig. 1).
Fig. 1: Vernier pattern and alignment marks on a 6 inch wafer, created with the MicroWriter ML 3, show that the overlay accuracy can be as good as +/- 0.5 µm.
Fig. 2: Exposure with “Virtual Mask Aligner” software: (a) A designed pattern, put on a sample before exposure, and (b) the exposed and developed sample.
Fig. 3: Real time microscope image of (a) a camera on the top and (b) a camera on the backside of the MicroWriter ML 3.
Alignment with randomly distributed samples can be performed using the software tool “Virtual Mask Aligner” (Fig. 2). Users can locate their samples and then digitally superimpose the design pattern with their sample in real time before the exposure. For the backside alignment, the MicroWriter ML 3 can be equipped with a backside alignment camera, which can feed in a real-time microscope image. (Fig. 3) It can also be used to expose a variety of different substrates, including diamond or liquid polymer. (Fig. 4)
Fig. 4: Exposure results of various substrates with the MicroWriter ML 3.
The MicroWriter ML 3 is a compact, powerful, and affordable direct-write optical lithography device that offers unprecedented value for money. It has a low cost of ownership, with long-life, solid-state light sources and low maintenance requirements. It also has an excellent environmental footprint: Power consumption of the device is comparable to that of a laptop.
