A review of microfabrication approaches for the development of thin, flattened heat pipes and vapor chambers for passive electronic cooling applications

• Published in: Micro and Nano Engineering 2024-03, Vol.22, p.100235, Article 100235
• Main Authors: Filippou, Ioannis, Tselepi, Vasiliki, Ellinas, Kosmas
• Format: Article
• Language: English
• Subjects: Flexible heat pipes; Metallic heat pipes; Polymeric heat pipes; Silicon heat pipes; Ultra-thin heat pipes; Vapor chambers
• ISSN: 2590-0072; 2590-0072
• DOI: 10.1016/j.mne.2023.100235

With the rapid development of microelectronics and the telecommunication industry, a variety of high performance, portable and slim electronic devices have become available. Miniaturization of devices and increased packing density of electronics can generate “hot spots” i.e. a high heat flux on a small area. Thus, in such devices the heat management requirements go beyond the limits of typical approaches and the development of miniaturized, high-performance thermal management concepts to cool high-performance, compact electronic devices is urgently required. To this direction, micro and nanofabrication methods can provide solutions in both miniaturizing existing concepts of passive cooling as well as in improving their performance. In this review, we start by introducing the most commonly used metrics used to evaluate the performance of passive cooling devices (i.e. vapor chambers and flattened heat pipes) together with the most prominent performance limitations. Then, in the main part, we present state of the art examples of microfabricated, thin vapor chambers and flattened heat pipes on rigid substrates (i.e. using metals and silicon), but also vapor chambers on thin and flexible polymeric or composite materials. Finally, the main conclusions and the steps which should be followed to further enhance the performance of such devices are summarized in the conclusions and future perspectives section. [Display omitted] •Microfabrication methods can provide ultra-thin vapor chambers.•Ultra-thin (< 500 μm) vapor chambers are rare in the literature.•Metals, Silicon and polymers are used for heat pipes and vapor chambers.•Flexibility and low thickness are the two basic requirements.