Description: The use of lithographic techniques for microfabrication of electronic and mechanical structures at the submillimeter level requires expensive facilities, extreme processing conditions, and timescales of the order of weeks to go from design to completed device. The Naval Research Laboratory has developed a novel laser-based direct-write approach for non-lithographic digital microfabrication of microelectronics and other devices that is simple, fast, economical and highly versatile. The technique uses laser-induced forward transfer to print patterns of complex inks or pastes. As shown in the schematic on the left, a focused pulsed UV laser beam passes through a ribbon support and interacts with an ink coating containing a suspension of the material to be deposited. Above an incident laser energy threshold, the ink is transferred across the gap in the form of three-dimensional pixels, or voxels. This laser printing technique has been used to make various devices and structures from a wide range of electronic, ceramic, composite, and even biological materials. A few examples are shown above on the right.

Advantages/Features Include:

  • Allows deposition under ambient conditions (in air and at room temperature).
  • Allows deposition of a wide range of materials, including metals, dielectrics, ferrites, polymers, composites and even chemically reactive materials.
  • Able to print complex patterns conformal to the surface of the receiving substrate.
  • Allows the transfer of complex fluids with a wide range of viscosities ranging from aqueous solutions and nano-inks to thick ceramic pastes or suspensions.
  • Capable of in situ curing of the printed inks using a second laser, with little effect on the regions surrounding the pattern.
  • Capable of write speeds approaching 1 m/sec with
  • Allows deposition of different materials for multilayer structures simply by exchanging ribbons.
  • Ideally suited for the integration of heterogeneous materials and components independent of the substrate type or its topology.

Applications Include:

  • Circuit repair and/or customization
  • Low volume manufacturing, rapid prototyping and development of new circuit architectures

References:

  • "Laser Direct-Write Techniques for Printing of Complex Materials," MRS Bulletin, 32, No. 1 (2007) 23.
  • "Laser Decal Transfer of Electronic Materials with Thin Film Characteristics," Proc. of SPIE, 6879 (2008) 687911.

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