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Microcontainers for Patterning Substrates with Colored Materials Disclosure Number: IPCOM000014135D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-19

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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