Authored By:
Rabindra N. Das, How T. Lin, Jianzhuang Huang, John M. Lauffer
Frank D. Egitto, Mark D. Poliks, Voya R. Markovich
Endicott Interconnect Technologies, Inc.
Endicott, New York USA
Transcript
Printing technologies provide a simple solution to build electronic circuits on low cost flexible substrates. In this paper, the authors examine the use of different materials in the area of printing technology. A variety of printable nano materials for electronic packaging have been developed. This includes nano capacitors and resistors as embedded passives, nano laser materials, optical materials, etc. Materials can provide high capacitance densities depending on composition, particle size and film thickness. The electrical properties of capacitors fabricated from nano composites showed a stable dielectric constant and low loss over a wide frequency range. Overall, printable materials will be useful for the production of multi-functional complex electronic packages. The results of this paper also suggest that printable nano materials may be attractive for roll-to- roll manufacturing of large-area microelectronics such as roll-up displays, e-papers, keyboards, radiofrequency structures, transistors, photovoltaics, medical devices and more.
Summary
Printing technologies provide a simple solution to build electronic circuits on low cost flexible substrates. Materials will play important role for developing advanced printable technology. Advanced printing is relatively new technology and need more characterization and optimization for practical applications. In the present paper, we examine the use of different materials in the area of printing technology. A variety of printable nanomaterials for electronic packaging have been developed. This includes nano capacitors and resistors as embedded passives, nano laser materials, optical materials, etc. Materials can provide high capacitance densities, ranging from 5nF/inch2 to 25 nF/inch2, 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 1MHz to 1000MHz. A variety of printable discrete resistors with different sheet resistances,ranging from ohm to Mohm, processed on large panels (19.5 inches x 24 inches) have been fabricated. Low resistivity materials, with volume resistivity in the range of 10-4 ohm-cm to 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 IR-reflow, thermal cycling, pressure cooker test (PCT), and solder shock. Change in capacitance after 3X IRreflow and after 1000 cycles of deep thermal cycling (DTC) between -55°C and 125°C was within 5%. Most of the materials in the test vehicle were stable after IR-reflow, PCT, and solder shock.
Conclusions
Printable materials are promising not only because they are versatile, but also economical compared to other methods. A variety of materials suitable in printable processes for the fabrication of selective and localized embedded components in PWB/LCC has been developed (Figure10). The materials and processes enable fine feature sizes and controlled thickness of deposited layers. This result is accomplished by using ink-jet, screening, and contact priting and dispensing processes. Experiments demonstrated that ink-jet printing and subsequent metal layer deposition is suitable for inductors, whereas screen or contact printing is suitable for conducting adhesives for interconnect applications.
Capacitors,resistors, ZnO and waveguide materials can use either ink-jet or screen/contact print processes based on their requirements and viscosity of solutions. Capacitors fabricated using a printing process showed high capacitance and low loss, and are reliable after IR-Reflow and DTC. Nanomaterials can produce variable resistance ranging from ohm to Mohm. Low k and loss materials can also be fabricated from nanocomposites. Overall, printable materials will be useful to produce multifunctial complex electronic packaging. The results also suggest that printable nanomaterials may be attractive for Roll-To-Roll manufacturing of large-area microelectronics such as roll-up displays, e-papers, keyboards, radiofrequency structures,transistors, photovoltaics, medical devices etc.
Initially Published in the IPC Proceedings
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