Printable electronics: towards materials development and device fabrication

• Published in: Circuit world Vol. 37; no. 1; pp. 38 - 45
• Main Authors: Das, Rabindra N., Lin, How T., Lauffer, John M., Markovich, Voya R.
• Format: Journal Article
• Language: English
• Published: Bradford Emerald Group Publishing Limited 01.01.2011
• Subjects: Analysis; Batteries; Composite materials; Devices; Dielectric properties; Dielectrics; Electronics; Epoxy resins; Iridium; Moisture absorption; Nanocomposites; Nanomaterials; Nanoparticles; Nanostructure; Particle size; Polymers; Printed circuit boards; Resistors; Screen printing; Studies; Temperature; Thin films; Viscosity; Zinc oxides; Resistors; Thin films; Composite materials; Capacitors; Printed circuits; Dielectric properties
• ISSN: 0305-6120; 1758-602X
• DOI: 10.1108/03056121111101278

Purpose - There has been increasing interest in the development of printable electronics to meet the growing demand for low-cost, large-area, miniaturized, flexible and lightweight devices. The purpose of this paper is to discuss the electronic applications of novel printable materials.Design methodology approach - The paper addresses the utilization of polymer nanocomposites as it relates to printable and flexible technology for electronic packaging. Printable technology such as screen-printing, ink-jet printing, and microcontact printing provides a fully additive, non-contacting deposition method that is suitable for flexible production.Findings - A variety of printable nanomaterials for electronic packaging have been developed. This includes nanocapacitors and resistors as embedded passives, nanolaser materials, optical materials, etc. Materials can provide high-capacitance densities, ranging from 5 to 25 nF in2, depending on composition, particle size, and film thickness. The electrical properties of capacitors fabricated from BaTiO3-epoxy nanocomposites showed a stable dielectric constant and low loss over a frequency range from 1 to 1,000 MHz. A variety of printable discrete resistors with different sheet resistances, ranging from ohm to Mohm, processed on large panels (19.5×24 inches) have been fabricated. Low-resistivity materials, with volume resistivity in the range of 10−4-10−6 ohm cm, depending on composition, particle size, and loading, can be used as conductive joints for high-frequency and high-density interconnect applications. Thermosetting polymers modified with ceramics or organics can produce low k and lower loss dielectrics. Reliability of the materials was ascertained by (Infrared; IR-reflow), thermal cycling, pressure cooker test (PCT) and solder shock testing. The change in capacitance after 3× IR-reflow and after 1,000 cycles of deep thermal cycling between −55°C and +125°C was within 5 per cent. Most of the materials in the test vehicle were stable after IR-reflow, PCT, and solder shock.Research limitations implications - The electronic applications of printable, high-performance nanocomposite materials such as adhesives (both conductive and non-conductive), interlayer dielectrics (low-k, low-loss dielectrics), embedded passives (capacitors and resistors), and circuits, etc.. are discussed. Also addressed are investigations of printable optically magnetically active nanocomposite and polymeric materials for fabrication of devices such as inductors, embedded lasers, and optical interconnects.Originality value - A thin film printable technology was developed to manufacture large-area microelectronics with embedded passives, Z-interconnects and optical waveguides, etc. The overall approach lends itself to package miniaturization because multiple materials and devices can be printed in the same layer to increase functionality.