Deposition
Atomic Layer Deposition (ALD) – A deposition technique that deposits in monolayers via self-limiting reactions. Results in high quality, extremely controlled and conformal thin films.
Low Pressure Chemical Vapor Deposition (LPCVD) – A deposition process performed in a vacuum chamber or furnace. Precursor gases are introduced and cracked by heat to recombine as a solid film at the sample surface. Temperatures are typically 600C to 1200C
Plasma Enhanced Chemical Vapor Deposition (PECVD) – A process similar to LPCVD where plasma is used to crack the gas and allow deposition at lower temperatures, typically 200C to 400C
Sputtering – A physical deposition mechanism whereby inert ions bombard a target of the desired material. The material is sputtered off of the target and deposits on the sample.
Evaporation – Material is vaporized under conditions of high vacuum and condenses to form a thin film on the cooler sample.
Electroplating – Material is deposited onto the substrate out of solution via electrically driven reaction
Patterning
Optical Lithography – A mechanism of patterning photosensitive material on the surface of a sample. Intense light passes through a patterned mask plate and then either strikes the sample directly or is reduced through high-resolution lenses first.
E-Beam Lithography – A direct write method in which a highly focused electron beam is scanned across the surface of sensitive resist material. E-beam is capable of resolution as high as a few nanometers, but very slow in comparison to optical processes.
Lift-Off – A thin layer of material is deposited on top of resist patterned by one of the aforementioned methods. The resist is then dissolved and the overlying material lifted off leaving the film deposited within the pattern.
Printing – Materials may be dissolved into ‘inks’ and then printed onto a sample via a high precision dot matrix printer.
Dip Pen Lithography – A specially configured AFM dips the tips into materials reservoirs and then very precisely places nanoscale drops onto the sample.
Etching
Wet etching – A resist patterned sample is immersed in a solution in which the underlying material is soluble. It is quick and easy for low resolution etching. A few specialized directional etches exist.
Gaseous Etching – Similar to wet etch, but gases may penetrate into finer features and etch byproducts are more easily removed.
Reactive Ion Etching – A tuned directional etch process whereby the patterned material is exposed to a reactive gas and bombarded with ions simultaneously at low pressure. The directional ions drive the etch allowing vertical structures and high-resolution pattern transfer.
Cleaning
Wet Clean – Wet processes intended to etch, dissolve, and rinse contaminants from the surface of the sample. Agitation, spray, and Sonication may add a physical component.
Plasma Clean – Plasma activated gas, commonly oxygen, reacts with contaminants on the surface yielding volatile byproducts.
Mechanical Processes
Dicing – Substrates are cut with a high precision saw into smaller pieces or die.
Lapping and polishing – Sample surfaces may be thinned and smoothed via an abrasive material or slurry and an ultra flat disk.
Chemical Mechanical Planarization – A specialized form of lapping in which chemicals are added to the slurry to adjust rate, selectivity, and polish level.
Thermal Processes
Annealing – Heating of a sample to change or enhance properties
Rapid Thermal Annealing – A specialized form of annealing in which the sample is exposed to quick bursts of radiant heat with the objective of affecting the surface of the sample while leaving the bulk unchanged.
Oxidation – Heating a sample to high temperatures in the presence of oxygen to create a thin, controlled thickness oxidized layer on the surface.
Doping and Diffusion – A sample is exposed to high heat and carefully selected contaminants to adjust the electrical characteristics of the surface. Time and temperature may be used to control the depth of penetration or diffusion.
Metrology
Profilometry – Optical reflection, physical contact, or atomic force are used to map the topography of the sample surface.
Optical Microscopy – A mechanism for evaluating the surface properties of a material or structure at resolutions significantly exceeding unaided visual acuity.
Scanning Electron Microscopy (SEM) –SEM is capable of imaging at magnifications from 100X to 1,000,000X with ultimate resolution in the vicinity of a nanometer.
Atomic Force Microscopy (AFM) – Veeco® NanoMan V Atomic Force Microscope features a tip-scanning system with a closed-loop XYZ scanner, NanoScope® V controller and a large-sample (up to 6”) stage. The tool can be used in Contact Mode, TappingMode™ ,PhaseImaging™, Force Spectroscopy, Lateral Force Microscopy and Tunneling AFM (TUNA).
Ellipsometry – An optical method for measuring film thickness and optical constants, ellipsometry is recognized as the highest resolution method for doing such.
Reflectometry – Simpler than ellipsometry, reflectometry is still a very powerful tool for measuring thickness of thin films
Electrical Testing – Instruments varying in complexity from the simple 4-point probe to parametric analyzers may be used to measure electrical qualities of bulk materials or individual microscopic devices.
Bonding
Wafer Bonding – Various mechanisms may be used to adhere two substrates together.
Flip Chip Bonding – Using a variety of materials, a chip is flipped, aligned and bonded with a substrate.
Wire Bonding – A mechanism for making interconnects between integrated circuits and external devices or printed circuit boards.
The LNF is a micro and nanofabrication facility. Our primary fabrication technologies evolve from microchip fabrication. These technologies have been tailored or modified to produce mechanical and optical devices in addition to electronics. Most of our hardware can handle small pieces up to 150mm round substrates. Silicon is the most common substrate material as it is relatively cheap, has a wide variety of useful properties, and is easy to machine. III-V materials also have a long history at the LNF. Substrates consisting of other materials with unique properties are becoming more common. This lab excels at combining technologies and materials within a single device, for example, optical or mechanical sensors with integrated processing circuitry and on board power generation.
Some of our recent acquisitions offer new, exciting opportunities to push the limits of small scale fabrication. These include a JEOL 6300FS 100kV E-beam system, 20 new 150mm Tempress furnace tubes, Kurt Lesker Lab 18 sputter systems, SPTS Pegasus deep silicon etchers, SPTS APS deep glass etcher, Tegal AlN sputter system, Hitachi SU8000 SEM, NanoInk nanopatterning system, NanoMan AFM.
For more detailed information on our capabilities, please visit the LNF wiki.