Microfabrication Laboratory (Clean Room) 1302

Quick Specs

Thin film deposition
Thermal processing
Microphotolithography
Chemical etching
Inspection and characterization
Optical profilometry
Bonding and packaging
Testing and measurement

EMSL's microfabrication laboratory provides a significant research and development capability for microstructures, microsensors, and microanalytical systems. Unlike highly automated industrial production equipment, EMSL's microfabrication equipment is flexible and multipurpose. The equipment supports a variety of microprocessing activities, including:

Thin film deposition
Thermal processing
Microphotolithography
Chemical etching
Inspection and characterization
Optical profilometry
Bonding and packaging
Testing and measurement.

Equipment Description and Operational Overview

EMSL's microfabrication equipment resides in a 1200-square-foot processing facility, subdivided into two Class 1000 clean rooms and an anteroom. Additional thin film deposition equipment and numerous state-of-the-art characterization instruments are located in adjacent lab areas. All work in the processing facility and with the microfabricaton equipment must be performed in compliance with EMSL practices and permits.

Thin Film Deposition

Wafer spin coaters

EMSL's thin film deposition equipment is located in a clean room and allows deposition of metals by thermal evaporation. A separate sputter deposition capability is dedicated to chromium coating for either typical adhesion improvement or specific chromium coating applications. As needed, interfacing with clean room activities also provides potential access to highly specialized large-area sputter deposition and e-beam deposition capabilities located on the Pacific Northwest National Laboratory campus.

Each sputter chamber is a 2x2x3-foot box, has a double planetary substrate holder, and allows samples up to 12 inches in diameter. The system's electron beam evaporation coater is equipped with one 6-crucible hearth and one 5-inch low-voltage deposition assist ion beam source. The sputter coater has two 4-inch magnetron cathodes and one 5-inch low voltage deposition assist ion beam source.

Other thin film deposition equipment in the clean room includes a Langmuir-Blodgett Trough for depositing ordered single layers or multilayer structures of aliphatic molecules. Chemical vapor deposition, such as metalorganic chemical vapor disposition (MOCVD), is available from an Emcore Discovery 75 MOCVD reactor that is placed in a nearby EMSL laboratory outside of the clean-room. Spin coating of sol-gel processed thin films can also be achieved with the help of two spin coating systems in the clean room.

Thermal Processing

Thermal processing is performed in two 4-inch Thermcraft 25-30-3ZH three-zone programmable tube furnaces. One furnace is dedicated to high-purity oxidation, and the other is used for various heat treatments, such as annealing metals or curing polymers. Both furnaces are closed-tube systems equipped with plumbing for introducing and exhausting gases. Several ovens, including a vacuum oven, are available as needed.

Microphotolithography

A UV mask aligner and exposure system allows photoresist processing to expose micro-features. The development of micro-patterns can be carried out with chemical processing. Photoresist processing equipment also includes a 6-inch SP-1000 spinner and dedicated bake hotplates. A Laurell Technologies WS-200-4T2 Teflon spinner is used for spin-casting materials other than standard positive and negative photoresists.

Chemical Etching

Wet chemical etching is performed in an 8-foot laminar flow wet bench equipped with teflon process tanks and an overflow deionized water rinser. For wet etching processes, deionized water better than 17.9 MΩmcr can be generated with an ultra-pure water system specially equipped to produce water that is ultra-low in organic concentrations.

Inspection and Characterization

Inspection capabilities of this system include a confocal Nikon Optiphot 66 microscope with video and image capturing software and an SMZ-U stereo microscope. Additional microscopes available include:

Olympus PMG-3 metallographic microscope with an image analysis system
Olympus BX-60 microscope with differential interference contrast lenses and an image analysis system
Olympus SZH10 stereo microscope.

Optical Profilometry

Optical profilometry provides measurement of large area surface roughness as well as film thickness by a non-contact method. This technique is based on precise z-scanning of the photodetector and measurement of focal planes at various heights. Precisions as high as 10 nm in the Z-direction can be comfortably achieved for opaque samples. A large area XY scanning capability with a stitching function can provide surface roughness at macroscales.

Bonding and Packaging

Bonding and Pacakaging

Bonding and packaging capabilities are provided by several instruments: a DISCO DAO-2H/5L1 dicing saw, a K&S universal eutectic die bonder, and two K&S 4123 wedge wire bonders. One wedge bonder is dedicated for aluminum wire and one for gold wire. An Asymtek 402B automated fluid dispensing system is used for die attaching, underfill epoxy, encapsulation, and liquid gasketing. The system allows deposition of both low- and high-viscosity materials as dots, continuous lines, or arcs 250 μm or larger in diameter and with a 20-μm resolution. A variety of accessories allow microjetting of materials from a larger distance, microspraying, and alternate dispensing of two materials. Both fluid and substrate temperatures can be controlled.

Test and Measurement

Electronic test and measurement equipment is based on a Hewlett Packard (HP) semiconductor test system for DC characterization of semiconductor devices (from sub-pA to 1 A). The system includes an HP 4142 modular DC source/monitor; a probe station with temperature control; a Unix computer; and HP VEE-Test and IC-CAP measuring software supporting SPICE, HSPICE, Saber, and MNS simulators. AC measurements are provided by two HP 4194A impedance analyzers and an HP 4284 LCR meter. Most of the electronic equipment supports GPIB communication and can be linked to a computer for experimental control and integration through LabView software.

Experimental Studies of Heterogeneous Gas-to-Particle Reactions Using Novel Particle-on-Substrate Stagnation Flow Reactor Approach (What Are the Chances?)

Saraf, Lax | lax.saraf@pnl.gov, 509-371-6508