Nanofabrication Capabilities & Tools
Major Capabilities: Instruments and Labs
Zeiss Crossbeam 1540 EsB
The Molecular Foundry Zeiss Cross-beam is one of the most versatile lithographic and inspection tools allowing fabrication of complex prototypes for nanoelectronics, nano-optical antenna, modifying scanning probe tips, rapid electrical contacting and many other applications. The 1500XB Cross Beam combines the Gemini field emission column (FESEM) with the Orsay Physics focused ion beam (FIB). In addition, the instrument offers a multi-channel gas injection system to allow ion and electron beam induced deposition (IBID and EBID) and chemically assisted ion beam etching (CAIBE). The tool can be used for lithographic patterning of materials or for inspection. Three-dimensional patterning is possible with FIB or CAIBE. Additions to the tool include a Xenos Pattern Generator and an Argon/Oxygen ion gun. The Xenos pattern generator allows the ion and electron beam to write computer-generated patterns while the Argon/Oxygen ion gun allows milling of layers over an area of several millimeters. Samples sizes can range from scanning probe tip size to four-inch wafers.
Oxford FlexAl -Plasma Enhanced Atomic Layer Deposition (ALD)
The FlexAl tool enables the deposition of thin films of a wide variety of materials with single atomic layer thickness control. Gas phase precursors are alternated with water or plasma (oxygen, nitrogen, ammonia) to induce high quality, conformal deposition. Plasma allows room temperature deposition, making processes on sensitive and soft materials possible. The tool can hold 8 precursors simultaneously, making this system ideal for the broad needs of our User base. It can accommodate wafers up to 200 millimeters, and samples as tall as 1 centimeter. Our standard, well developed, processes currently include:
- Hafnium oxide
- Aluminum oxide
- Titanium dioxide
- Silicon dioxide
- Tungsten oxide
- Cobalt oxide
Oxford PlasmaLab 150 Inductively Coupled Etcher Fluorine (ICP Fluorine)
ICP Fluorine is an inductively coupled etcher where the ion energy at the wafer can be controlled independently from the plasma density. This tool can etch at much lower pressures than the RIE and generally achieve higher etching rates. It is intended for etching materials with fluorine and/or oxygen based gas chemistry. Common applications are silicon etching with SF6/O2 at temperatures below -60C, and polymer etching at -100 C. The tool has a temperature range of -140C to 400C and helium backside cooling to assist with heat exchange between the wafer and chuck. In addition to the 13.56 MHz source on the bottom electrode, there is a low frequency source to assist with charge management at the etched surface. Wafer sizes accepted run from pieces to 8 inch wafers.
Oxford PlasmaLab 150 Inductively Coupled Etcher Toxic gas (ICP toxic gas)
ICP 1 is an inductively coupled etcher where the ion energy at the wafer can be controlled independent of the plasma density. This tool can etch at much lower pressures than the RIE (Oxford 80+) and generally achieve higher etching rates. It is intended for etching materials with non-fluorine based gas chemistry. Common applications are silicon etching with Cl2 or HBr and high selectivity to oxide or GaAs with BCl3 and nitrogen chemistry. The tool has a temperature range of -140C to 400C and helium backside cooling to assist with heat exchange between the wafer and chuck. Wafer sizes accepted run from pieces to 8 inch wafers.
Zeiss Ultra 60-SEM
The Zeiss Ultra 60 is a Scanning Electron Microscope using the good imaging capabilities of the GEMINI® field emission column (FESEM). It comprises dual In-column detectors for ultra high resolution topographical and compositional imaging. The new In-column EsB (Energy selective Backscatter) detector is less sensitive for edge contrast and charging effects which enables precise feature imaging and reliable metrology. It delivers superb materials contrast and crystallographic imaging.
Vistec VB300 Electron Beam Lithography System
A fundamental piece of equipment in any nanofabrication laboratory is the electron beam lithography (EBL) system. The VB300 is a state-of-the-art tool from Vistec Lithography Limited (now Raith) used to create lithographic patterns in a resist for applications in areas such as nanoelectronics, photonics, biotechnology, and magnetics. The tool spot size is less than 3 nm allowing sub-10 nm features to be patterned. Overlay accuracy is 2-10 nm within the 1.2 mm writing field and 15-30 nm field-to-field. The tool runs throughout the day and night to maximize usage. The EBL can handle wafer pieces and full wafers up to 200 mm. A 300 mm handler is planned for the future. The e-beam is operated by Molecular Foundry staff and not directly by Users.
80+ Reactive Ion Etcher (RIE)
This RIE is a capacitive parallel plate etcher suitable for up to 8 inch wafers. The etcher is intended for 1) plasma cleans and descums with oxygen 2) etching of materials with fluorocarbon chemistries (e.g. silicon based materials, tungsten, and more) 3) deposition of amorphous carbon. The tool does not have helium backside cooling. Long etches and higher power plasmas will cause an increase in the wafer temperature which can affect the fine detail of the etched feature size and shape.
80+ Plasma Enhanced Chemical Vapor Deposition (PECVD)
The PECVD is a dual frequency plasma-enhanced deposition tool. Materials can be deposited including undoped amorphous silicon, silicon dioxide, and silicon nitride. Deposition temperatures range from O-400 °C. Wafer pieces to 8" wafers can be accepted.
NEW: Oxford Plasma lab 100 Viper (FY2013)
The Viper is a multiple frequency parallel plate etcher with 60 MHz on the top plate and 13.56 MHz on the bottom plate (low frequency source for charge management also available). Like the ICP, the ion energy at the wafer can be controlled independent of the plasma density. However, ion densities are lower than in an ICP. Etch rates can be slowed and selectivities increased for controlled nanoscale etching. This tool came on-line July 2013 and is the first of its kind delivered to the US. This tool is intended for nanoscale silicon oxide and silicon nitride etching and experimental nanoscale etching. The tool has a temperature range of -140C to 400C and helium backside cooling to assist with heat exchange between the wafer and chuck. Recipe development is in progress. Wafer sizes accepted run from pieces to 8 inch wafers.
The roughly 4,850 square foot (450 m2) cleanroom, mainly Class 1000, includes Class 100 and Class 10 areas for nanofabrication/lithography, clean measurements and electron beam lithography
Other Lithographic tools
- Molecular Imprint Imprio 55 flash imprint lithography (S-FIL™)
- Homemade air cushion imprinting system
- Homemade thermal imprinting system
- ABM optical contact printer for 4 inch wafers
- Semicore SC600 e-beam (6 pockets) and thermal evaporator
- Home-made electroplating station gold, nickel, silver
- Home-made close spaced sublimation
- Wafab solvent bench VLF for organic flammable solvents (stainless steel)
- Wafab acid and base bench VLF for wet etching (Polypropylene)
- Wafab utility bench VLF for a large variety of wet processes (Polypropylene)
- VWR ultra-sonic cleaning bath
Inspection and Characterization
Horiba Uvisel Spectroscopic Ellipsometer: It measures thin film thickness and optical constants and provides information on material properties such as anisotropy, chemical composition and electrical conductivity. Veeco Caliber SPM – AFM (CA260701)
- Veeco Dektak 150 stylus profiler (250G8)
- Zeiss optical microscope
- Leica optical microscope
- Homemade electron flood gun for large area exposure
- Ramé-Hart contact angle goniometer
- L-Edit layout editor CAD for GDSII
- RSoft photonics simulation software:
- FullWAVE finite-difference time-domain (FDTD)
- BandSOLVE plane wave expansion (PWE) algorithm
- FemSIM finite element method (FEM)
- Lumerical FDTD computational package
The ultrafast laser lab is a beam-line style User Facility for lithography, characterization, and deposition technique development. A two-photon photolithography instrument will allow for three-dimensional photolithographic structures on the sub-micron scale. This instrument will be implemented with a force probe and near-field plasmonic tip structure to allow for 3D structure lithography at single-digit nanoscale dimensions. For characterization, an ultrafast-systems transient absorption spectrometer has been installed and allows the monitoring of electronic relaxation dynamics on sub 100-femtosecond time scales. In addition, femtosecond stimulated Raman instrumentation is being developed to probe charge transfer dynamics and gas phase thin film deposition precursor photochemistry. Finally, we are developing a new type of atomic layer deposition process that will use gas phase photochemistry to prepare active precursors of a wide variety of materials. Coherent Libra amplified femtosecond laser (45 fs pulse duration)
- Coherent OPerA solo OPA tunable source (270 nm - 2600 nm)
- Ultrafast systems transient absorption spectrometer
- Home-built femtosecond stimulated Raman system for solid, liquid, and gas phase (~20 fs temporal resolution)
- Home-built high temporal resolution transient absorption system for both bulk and microscopic samples (~20 fs)
- Home-built second harmonic generation microscope
- Biophotonic solutions MIIPS Box 640 pulse shaper for coherent control and microscopy applications