The Microfabrication Group in PML's Quantum Electromagnetics Division is responsible for operation of the state-of-the-art Boulder Microfabrication Facility (BMF). The BMF is a 1700 square meter (18,000 square foot), ISO class 5 (class 100), clean room dedicated to providing state-of-the-art micro- and nano-fabrication capabilities to meet the microelectronic and microelectromechanical systems needs of NIST-Boulder staff members and their direct
Electron Beam Lithography: The JEOL JBX-6300FS e-beam lithography tool allows wafer-level lithography of features as small as 8 nm. Compared to our former capability, it has 1000 times better position registration and 1000 times faster write speed. It will facilitate advances in nanoscale metrology and the fabrication of quantum information devices, single-photon detectors, biomagnetic reporters, magnetic sensors and memory elements, and superconducting devices.
Maskless Aligner: The Heidelberg MLA-150 is a versatile optical lithography tool used to directly write a pattern onto a wafer using either a 375 nm or a 405 nm wavelength laser. The tool can accommodate substrate from 1 cm chips to 150 mm wafers and write with a resolution of 0.9 µm. It has decreased the cycle time for rapid prototyping of designs by eliminating the need for optical reticles or masks.
Integrated Photonics: The BMF is investing in infrastructure and tooling to support integrated photonics. Recent examples include a dielectric thin-film sputtering system and plumbing a plasma-enhanced chemical vapor deposition (PECVD) system with deuterated silane (SiD4) in order to produce higher optical quality dielectric films. Optical quality can be measured with two new tools: a white light spectrophotometer and a Metricon prism-coupled spectrometer. The BMF is procuring a wafer bonder, a three-dimensional optical printer and interconnect tool, a die-bonder, an indium deposition system, an additional PECVD system with process gasses for optical films, and an atomic-layer deposition system.
Chemical-Mechanical Polishing: As circuits become more complicated and require an increasing number of layers, thicker films are required to cover the steps in previous layers, which can limit functionality and feature size. We recently purchased a chemical-mechanical polishing machine that can planarize layers of silicon dioxide. It has allowed researchers to fabricate more complex circuitry and polish optical films that were roughened during the fabrication processing.
Furnaces: A critical step in preparing silicon wafers for device fabrication is the growth of an initial layer of thermal oxide or silicon nitride. We are installing a bank of four furnace tubes to grow thick silicon oxide layers using steam; thin oxides using a wet/dry oxidation process; and silicon nitride, polycrystalline silicon, and silicon oxy-nitiride using chemical vapor deposition.