The conventional method for manufacturing 3D nanostructures consists of stacking layers on a silicon chip. The first step is to define a pattern in the photoresist, using a mask and UV light. The etching or deposition of material in the layer then provides the desired shape. Dozens of layers are stacked to produce the chips themselves. However, there are restrictions on the number of layers that can be stacked, since layers that are relatively far apart can become randomly displaced with respect to one another, interfering with the chip’s functionality.
The researchers have developed a 3D mask that can define the structure on two sides of the wafer simultaneously, making it possible to define a 3D nanostructure on a chip in a single process. This ensures that both sides of the chip are aligned, guaranteeing the vertical alignment of the 3D nanostructure.
The method is said to open the way for the mass production of chips in which various functionalities are positioned close together and the researchers are investigating ways of implementing this technology in practice. There are possible applications in the medical world, for example by combining an optical sensor for proteins with a data processing chip and a magnetic memory.
Professor Willem Vos of the Complex Photonic Systems group (COPS) at MESA+ said: “Our method makes it possible to combine an endless variety of features on a chip, such as electronics, optics, magnets and microfluidics.”
