Micro-Electro-Mechanical Systems (MEMS) is a technology that fabricates microdevices (microcomponents) of micrometer size. The technology has already been practically applied to various sensors (e.g. gyroscopes, acceleration sensors) and also to information devices (e.g. inkjet printer heads, digital mirror devices used in projectors); it is expected that the fundamental technology will be further utilized in the fields of life science and chemosynthesis.

Although MEMS, semiconductor processing technology, micromachining and precision molding technology are widely recognized as the current leading-edge microfabrication technologies, they still have the following limitations and points to be improved:

• Limited type of microdevice shapes that can be fabricated;
• Limited variation of materials that can be handled.

In order to overcome these technological challenges, Fuji Xerox aimed to newly establish a three-dimensional microfabrication technology that combines semiconductor process and lamination modeling, and also aimed to realize a more advanced method of fabricating microdevices (microcomponents). The resulting microfabrication technology developed by Fuji Xerox is called FORMULA, which stands for “FORmation of μ-structures by Lamination”. Some of the key features of this technology are that it:

• Can form real three-dimensional microstructures;
• Can fabricate structures with nanometer accuracy;
• Can handle various materials, such as metals (e.g. aluminum and copper) and semiconductor (e.g. silicon); and
• Enables batch manufacturing

Furthermore, overhung structures and hollow structures can be fabricated without using sacrificial layers. Thus, the whole fabrication process becomes much easier.

Application areas of the technology include: Micromachine components Micromolds Micro-optical components (microlens, diffractive optical components, etc.) Microchannel （microreactor, microcooler, etc.）

FORMULA is a new technology for the fabrication of microstructures using transfer- lamination of a thin film formed through lithography. As shown in Figure 1, the technology is a type of lamination modeling that uses a semiconductor process to shape the various cross-sections of a structure on the substrate collectively and simultaneously, and to transfer and laminate this structure on a different substrate, using surface-activated bonding. The streaming video offered below can assist you in gaining a better understanding of the principle of this unique processing technology.




Lamination modeling makes possible the formation of complete three-dimensional structures, and the semiconductor process enables the fabrication of cross-sectional patterns with nanometer accuracy. Moreover, no adhesive material is required to firmly bond layers. Thus, it is possible to fabricate robust structures with high accuracy. The following are some micromachine components fabricated using FORMULA technology.

Figure 2 shows “Mount Fuji” at one hundred millionth of its actual size, which is fabricated by laminating 23 one-mm-thick aluminum thin films.

Figure 3 shows a diffractive optical element, which is fabricated by laminating six 170-nm-thick aluminum thin films; it also displays the fine stairstep-shape profile of the same structure.

Figure 4 shows a microfluidic device, which is fabricated by laminating cross-section patterns made of electroplates. This three-dimensional microfluidic device is fabricated without using any sacrificial layer. Laminar flow is formed when liquid or gas flows in such narrow flow paths, and it enables well-controlled chemical reactions to be initiated with high reproducibility.

Figure 5 shows a woodpile structure, which is fabricated by laminating electroplated patterns, and it indicates that a complex structure can be accurately fabricated.