PNNL-13501 - Pacific Northwest National Laboratory

Study Control Number: PN98048/1294
Microfabrication in Ceramic and Plastic Materials
Peter M. Martin, Dean W. Matson, Wendy D. Bennett
Miniature devices have been engineered for a variety of special-purpose applications, such as hydrogen production,
heating and cooling, and chemical separations. Microfabrication capabilities and methods are essential for developing
devices used in microfluidic-based chemical processing and thermal control applications. This project was aimed at
developing fabrication capabilities for polymer-based microfluidic applications.
Project Description
The purpose of this project is to build capabilities and
methods for fabricating microfluidic devices for
microchemical and thermal systems. Emphasis during the
current fiscal year has been on laser micromachining and
bonding processes, primarily for use in producing
polymer-based microfluidic components. A major goal of
the project was developing staff expertise on a throughmask
excimer laser micromachining station procured with
non-LDRD funding by the Laboratory during fiscal year
2000. We also investigated adhesives and methods for
producing laminated microchannel plastic components.
These capabilities were used extensively for other
projects as well as a number of other programs within the
Laboratory. We also designed and fabricated a plasticbased
meso-scale electro-hydrodynamic fan intended to
concentrate low-pressure gases.
Introduction
Development of microchemical and thermal systems
requires the capability to produce laminated microchannel
and other microfluidic components. Previous work in
producing such laminated microfluidic devices has
concentrated on using metals and ceramics because of the
high-temperature capabilities of those materials.
However, applications in which lower operating
temperatures and/or reduced component weight are
required make plastic materials attractive. Fabrication
costs for microfluidic plastic components can also be
considerably lower than for comparable metal or ceramic
components where high temperature and vacuum bonding
processes may be required. An additional attractive
feature of plastic materials for microfabrication is that
they are generally amenable to laser micromachining
methods.
322 FY 2000 Laboratory Directed Research and Development Annual Report
Approach
Laser micromachining is a powerful tool for producing
micrometer to hundreds of micrometer-scale features in
plastic components. A Resonetics Maestro Ultraviolet
excimer laser micromachining station was purchased and
evaluated for producing microchannels, micro-drilled hole
arrays, and other microscale features in a variety of
polymeric and other materials.
Bonding methods were evaluated for laminated plastic
components to be used for a variety of applications and
conditions. Adhesive application and bonding methods
were evaluated, primarily for the production of
multichannel laminates suitable for use in microfluidic
heat exchangers and related components. Conditions
necessary for heat bonding plastic components without
distorting or destroying micromachined surface features
were also evaluated.
Results and Accomplishments
Capabilities and limitations of the Resonetics Maestro
laser micromachining station were established. The
potential of the unit for machining individual holes and
microhole arrays, microchannels, and other similar
micromachined features were evaluated. The capability
of the unit to machine a range of materials from
thermoplastics and fluoropolymers to metals and ceramics
was tested. Operators were able to spend the time to learn
the programming software and develop the methods to
import drawings and patterns to be machined from outside
sources. Operators of the Resonetics system are now
sufficiently familiar with the machine and its capabilities
to use it effectively and efficiently as needed.