This paper compares the thermomechanical behavior of 3D inkjet printed microelectronics devices relative to those fabricated from traditional methods. It discusses the benefits and challenges in the adoption of additive manufacturing methods for microelectronics manufacture relative to conventional approaches. The critical issues related to the design and reliability of additively manufactured parts and systems stem from the change in the manufacturing process and the change in materials utilized. This study uses numerical modelling techniques to gain insight into these issues. This article is an extension of a paper on the same topic presented at the 2018 IEEE Electronics Packaging Technology Conference [1]An introduction providing an overview of the area, covering salient academic research activities and discussing progress towards commercialization is presented. The state-of-the-art modular microelectronics fabrication system developed within the EU NextFactory project is introduced. This system has been used to manufacture several test samples, which were assessed both experimentally and numerically. A full series of JEDEC tests showed that the samples were reliable, successfully passing all tests.The numerical model assessing the mechanical behavior of an inkjet-printed structure during layer-by-layer fabrication is presented. This analysis predicts that the stresses induced by the UV cure process are concentrated toward the extremities of the part and, in particular, in the lower layers which are constrained by the print platform.Subsequently, a model of a multilayer microelectronics structure undergoing JEDEC thermal cycling is presented. The model assesses the differences in mechanical properties between a conventional FR4/copper structure and an inkjet-printed acrylic/silver structure. The model identified that the influence of the sintering process on subsequent material properties, behavior of the inject-printed structure, and reliability of the inject-printed structure is significant.Key findings are that while stresses in the conventional and inkjet boards are relatively similar, the inkjet-printed board exhibits significantly greater deformation than the standard board. Furthermore, the mechanical stresses in the inkjet fabricated board are strongly dependent on the elastic modulus of the sintered silver material, which, in turn, is dependent on the sintering process.

The development of a surrogate modelling approach to aid design of 3D printed electronics packaging structures is presented, alongside a detailed overview of manufacture and reliability of a representative test structure. An overview of the current status in 3D printing in the electronics packaging sector is provided. Subsequently, a surrogate modelling approach for correlating thermomechanical stresses within a package to a number of design parameters is presented. This approach enables the design of a package to be considered in a more insightful manner and can additionally be integrated into condition based monitoring tools capable of enhancing product robustness. An overview of an advanced electronics packaging system capable of 3D printing electronics packages is presented.The system combines inkjet printing and curing of multiple materials, including conductive silver inks, with precision component placement, multi-material dispensing and 3D inspection systems to provide a highly flexible solution for rapid manufacture of electronics packages. Test structures manufactured using the system were subjected to a vigorous set of reliability tests. Details of the test regime and related results are presented. All tests were passed, indicating the robustness of the described manufacturing process.The key originality of the work is that it provides a comprehensive overview of the journey from design assessment an optimisation, through the manufacturing process and on to reliability testing. Areas of novelty in this work are associated with the development of fast, accurate surrogate models able to predict key reliability factors in response to a range of design parameters and insight into the development of a 3D manufacturing system for electronics packaging.