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Microcontainers for Patterning Substrates with Colored Materials

IP.com Disclosure Number: IPCOM000014135D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 6 page(s) / 298K

Publishing Venue

IBM

Abstract

Disclosed is a strategy to form chemical patterns on substrates using microcontainers (MCNs). MCNs are formed by patterning a series of lids or cavities through a layer; they are used by placing them into contact with a substrate and filling directly their lids with the desired chemical, Figure 1. Patterning of the substrate can result by localizing a chemical reaction with the substrate within the lids or from leaving over the substrate chemicals after removal of the MCNs. This approach offers several advantages over the patterning of substrates with other approaches such as microfluidic networks (MFNs) and seems well adapted to the patterning of substrates with colored materials.

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Microcontainers for Patterning Substrates with Colored Materials

  Disclosed is a strategy to form chemical patterns on substrates
using microcontainers (MCNs). MCNs are formed by patterning a
series of lids or cavities through a layer; they are used by
placing them into contact with a substrate and filling directly
their lids with the desired chemical, Figure 1. Patterning of the
substrate can result by localizing a chemical reaction with the
substrate within the lids or from leaving over the substrate
chemicals after removal of the MCNs. This approach offers several
advantages over the patterning of substrates with other approaches
such as microfluidic networks (MFNs) and seems well adapted to the
patterning of substrates with colored materials.

    Microcontact printing (MCP) [1], micromolding in capillaries
(MIMIC) [2] and microfluidic networks (MFNs) [3] are techniques
which offer an alternative to photolithography for the patterning
of substrates with chemicals. Microcontact printing places
directly molecules from an ink onto a substrate in the regions of
contact between a micropatterned stamp and the substrate.
Micromolding in capillaries relies on the displacement and curing
of prepolymers within capillaries to leave a pattern of
polymerized material on the substrate after removal of the
network of capillaries. Using MFNs is done in a similar way but
uses chemicals carried by a fluid traveling inside microchannels
to effect the chemical patterning of the substrate.

    MCP is limited in its ability to transfer any type of ink
from a stamp to a substrate: this technique usually requires a
stamp-compatible ink, which must be nondiffusive and nonvolatile.
MIMIC and MFNs are probably more general techniques because they
guide a fluid over a substrate but displacing a fluid can be
difficult to achieve: filling of the channels rely on capillary
forces. As a consequence, filling long or narrow channels or
using a viscous fluid may hamper these techniques. An example for
which filling is impractical concerns the filling of channels
with colored material to pattern substrates for display
applications.

    A viscous fluid like a photopolymer for color filters cannot
fill micron-sized channels over distances > 25 mm, for example.
Filling small channels (<10 mm in width or depth) suffers from
the friction between the moving fluid and the walls of a small
channel which accumulates as the fluid advances into the
channels. Discontinuous derivatization of a substrate using a MFN
or MIMIC is not obviously possible unless microchannels are
three-dimensional. MFNs often include filling and flow promoting
pads to provide an access to the channels and favor a fair supply
of reactants. For a large series of independent microchannels
each having at least one filling pad, the fraction area of the

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substrate covered by the pads can be too high. This imposes a
practical limit to the number of different reactions that can be
done in parallel on a substrate.

    MCNs provide a remedy to the above...