This work presents fabrication techniques for achieving individual electronic components both on the surface and within the fibers of a paper substrate, attaining full integration of paper and functional electronics materials. A process of hydrophobic wax patterning coupled with conductive and semiconductive poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid) (PEDOT: PSS)-based ink injection and screen-printing has allowed for the implementation of all-paper-based, tunable resistors, capacitors, and transistors. The characteristics of the paper resistors can be adjusted as desired through finetuning of the PEDOT: PSS- based ink recipe, and the components can be combined in various arrangements to attain paper-based printed circuit boards (PCBs) for a wide range of practical applications. As a first step towards multiple component integration, a simple example circuit design is demonstrated that incorporates the three different components. Furthermore, through the strategic organization of the resistors, transistors, and capacitors and stacking of paper layers, more complex and diverse paper PCBs can be attained while minimizing the perceived surface area of the circuitry, allowing for a compact, pliable, and highly customizable means of fabricating paper-based electronic systems.
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Viscoelastic Influence On the Board Level Assessment of Wafer Level Packages Under Drop Impact and Under Thermal Cycling
Abstract Structural components such as printed circuit boards (PCBs) are critical in the thermomechanical reliability assessment of electronic packages. Previous studies have shown that geometric parameters such as thickness and mechanical properties like elastic modulus of PCBs have direct influence on the reliability of electronic packages. Elastic material properties of PCBs are commonly characterized using equipment such as tensile testers and used in computational studies. However, in certain applications viscoelastic material properties are important. Viscoelastic influence on materials is evident when one exceeds the glass transition temperature of materials. Operating conditions or manufacturing conditions such as lamination and soldering may expose components to temperatures that exceed the glass transition temperatures. Knowing the viscoelastic behavior of the different components of electronic packages is important in order to perform accurate reliability assessment and design components such as printed circuit boards (PCBs) that will remain dimensionally stable after the manufacturing process. Previous researchers have used creep and stress relaxation test data to obtain the Prony series terms that represent the viscoelastic behavior and perform analysis. Others have used dynamic mechanical analysis in order to obtain frequency domain master curves that were converted to time domain before obtaining the Prony series terms. In this paper, nonlinear solvers were used on frequency domain master curve results from dynamic mechanical analysis to obtain Prony series terms and perform finite element analysis on the impact of adding viscoelastic properties when performing reliability assessment. The computational study results were used to perform comparative assessment to understand the impact of including viscoelastic behavior in reliability analysis under thermal cycling and drop testing for Wafer Level Chip Scale Packages.
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- Award ID(s):
- 1738811
- NSF-PAR ID:
- 10332776
- Date Published:
- Journal Name:
- Journal of Electronic Packaging
- ISSN:
- 1043-7398
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1115/1.4054784
