Simplified Complimentary Metal-oxide-semiconductor Manufacturing Technique

The technology is an innovative process for creating metal-patterned, structured membranes for micromachining applications. The method uses potassium hydroxide to remove silicon, in combination with XHRiC. Hafnium metal is first patterned onto a silicon nitride wafer, which serves as the starting substrate. XHRiC is then applied to the wafer, followed by patterning with photoresist and etching using O2 plasma to define cut slots in the membrane. The photoresist is then removed. Next, the wafer is bonded to a Pyrex carrier wafer with wax, and the backside of the silicon nitride is patterned and reactive-ion etched. The wafer is then placed in hot potassium hydroxide for 16 hours to remove the silicon layer, creating a silicon nitride membrane. The wafer is subsequently placed in acetone to dissolve the wax. The wafer is resecured to the Pyrex carrier wafer, and the topside of the silicon nitride membrane is subjected to reactive-ion etching. Finally, the XHRiC layer is removed using O2 plasma, and the Pyrex handle wafer is released, resulting in a metal-patterned silicon nitride membrane with cut slots. This novel process supports the creation of structured membranes with a wide range of applications in MEMS fabrication. The use of XHRiC as a patterned hard mask and/or etch protection material enables its application in various MEMS devices. The process can be used to fabricate cut membranes, micro/nano structures, and ultra-thin films for device applications, making it an excellent candidate for MEMS foundry companies and accelerometer manufacturers. It has reached a Technology Readiness Level (TRL) 5 (component validation in a relevant environment) and is now available for patent licensing.

Fabrication of NASA's pupil mask begins with the preparation of a silicon wafer, which serves as the foundation for the black silicon structure. The wafer undergoes ion beam figuring (IBF), a non-contact technique that precisely removes surface irregularities at the nanometer scale. This process ensures that the silicon surface is diffraction-limited, eliminating errors that could degrade optical performance. Once the wafer is polished to the required precision, it is then processed lithographically to define the mask pattern, creating reflective and absorptive regions essential for controlling light propagation. To achieve the desired high absorption characteristics, the lithographically patterned wafer undergoes cryogenic etching, a sophisticated process that transforms the silicon surface into a highly textured, black silicon structure. This method utilizes a controlled plasma environment with sulfur hexafluoride (SF6) and oxygen to etch the surface at cryogenic temperatures. The process is carefully optimized by adjusting parameters such as gas flow rates, chamber pressure, ion density, and etch duration, leading to the formation of high-aspect-ratio nanostructures on the silicon substrate. These structures, resembling a dense “forest” of silicon nanospikes, trap and diffuse incoming light, drastically reducing specular reflection. The resulting surface exhibits an ultra-low reflectivity that is orders of magnitude lower than conventional polished silicon. By leveraging NASA’s cutting-edge fabrication technique, the newly developed black silicon pupil mask offers a powerful solution for high-contrast astronomical imaging. Its ability to minimize scattered light and enhance optical contrast makes it an ideal component for space telescopes tasked with directly imaging exoplanets as well as other applications requiring ultra low reflectivity systems.

This invention provides a method and system for fabricating a biomarker sensor array by dispensing one or more entities using a precisely positioned, electrically biased nanoprobe immersed in a buffered fluid over a transparent substrate. Fine patterning of the substrate can be achieved by positioning and selectively biasing the probe in a particular region, changing the pH in a sharp, localized volume of fluid less than 100 nm in diameter, resulting in a selective processing of that region. One example of the implementation of this technique is related to Dip-Pen Nanolithography (DPN), where an Atomic Force Microscope probe can be used as a pen to write protein and DNA Aptamer inks on a transparent substrate functionalized with silane-based self-assembled monolayers. But it would be recognized that the invention has a much broader range of applicability. For example, the invention can be applied to formation of patterns using biological materials, chemical materials, metals, polymers, semiconductors, small molecules, organic and inorganic thins films, or any combination of these.

This technology consists of a photoelectrochemical cell composed of thin metal oxide films. It uses sunlight (primarily the ultraviolet (UV), visible and Infrared (IR) portions)) and inexpensive titanium dioxide composites to perform the reaction. The device can be used to capture carbon dioxide produced in industrial processes before it is emitted to the atmosphere and convert it to a useful fuel such as methane. These devices can be deployed to the commercial market with low manufacturing and materials costs. They can be made extremely compact and efficient and used in sensor and detector applications.

The technology uses additive print manufacturing to produce hierarchical and integrated structural and functional elements into large-area thin-film structures. Adding these structural and functional elements has the potential to enable very lightweight, large-scale thin-films with improved damage tolerance, self-deployment capability, flexibility, and multifunctional (optical, thermal, electrical) connectivity and interrogation capabilities. Based on simple and proven additive manufacturing concepts, advanced geometrical, biomimetic (insect wing), and hierarchical structures could be applied to, or eventually with further development integrated within the bulk of large-area thin films using roll-to-roll processing techniques for a potentially low-cost manufacturing approach. The subject technology potentially addresses many of the disadvantages of current large-scale membrane material systems, which are prone to damage or require extensive deployment and support structures.