A novel laser transfer process for direct writing of electronic and sensor materials

MAPLE direct write (MAPLE DW) is a new laser-based direct-write technique which combines the basic approach employed in laser-induced forward transfer (LIFT) with the unique advantages of matrix-assisted pulsed-laser evaporation (MAPLE). MAPLE DW utilizes an optically transparent substrate coated on one side with a matrix consisting of the material toe transferred mixed with a polymer or organic binder. As in LIFT, the laser is focused through the transparent substrate onto the matrix. When a laser pulse strikes the matrix, the binder decomposes and aids the transfer of the material of interest to an acceptor substrate placed parallel to the matrix surface. MAPLE DW is a maskless deposition process which operates in air and at room temperature. Powders of Ag, BaTiO3, SrTiO3, and Y3Fe5O12 with average diameters of 1 mu m were transferred onto the surfaces of alumina, glass, silicon, and printed circuit board substrates. Parallel-plate and interdigitated capacitors and flat inductors were produced by MAPLE DW over Rogers RO4003 substrates. MAPLE DW was also used to transfer polymer composites for the fabrication of gas sensor chemoresistors. One such composite chemoresistor fabricated with polyepichlorohydrin/graphite was used to detect organic vapors with a sensitivity of parts per million.