{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/117546"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/117546","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Immersion cooling and monolithic packaging for the thermal management of high-power density electronics","abstract":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","abstract_html":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","abstract_has_math":false,"creators":["Gebrael, Tarek"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Miljkovic, Nenad","Alleyne, Andrew G","Braun, Paul V","Pilawa-Podgurski, Robert"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-12","date_published":"2022-12","updated_at":"2026-07-22T22:24:56Z","subjects":["Electronics","Gan","Cooling","Packaging","Immersion","Water","Coating"],"languages":["en","eng"],"rights":["Copyright 2022 Tarek Gebrael"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/117546","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Miljkovic, Nenad","Alleyne, Andrew G","Braun, Paul V","Pilawa-Podgurski, Robert"]},{"key":"dc:creator","label":"Author","values":["Gebrael, Tarek"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-12","2022-11-10"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Electronics","Gan","Cooling","Packaging","Immersion","Water","Coating"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2022 Tarek Gebrael"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/117546"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","The student, Tarek Gebrael, accepted the attached license on 2022-11-06 at 16:07.","The student, Tarek Gebrael, submitted this Dissertation for approval on 2022-11-06 at 16:24.","This Dissertation was approved for publication on 2022-11-10 at 16:09.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18556 on 2023-04-12 at 11:34:50","With the advancement of electrical systems comes a dire need for developing new thermal management techniques that can dissipate the ever-increasing heat generated by high-power density electronics. As we are increasingly depending on big data, connectivity, autonomous systems, electric infrastructures, and transport enabled by renewable energy, the amount of heat we are generating per unit volume is simultaneously, and considerably, increasing. The continuation of this power densification, and the resulting performance improvement, strongly depends on the development of cooling solutions capable of dissipating the generated heat while keeping the temperature of the electronics in a range suited for their optimal performance. Furthermore, the move towards reducing carbon footprint and achieving energy security necessitates efforts to reduce the power needed to operate those cooling systems. This dissertation focuses on developing electronics packaging and cooling techniques that enhance the thermal management efficiency by increasing the heat transfer coefficient, increasing the heat spreading surface area, increasing the surface area for uniform cooling, and shortening the distance between the heat-generating elements and the cooling solution. In summary, we introduced two board-level monolithic packages made of Aluminum Nitride / Parylene C and Copper / Parylene C respectively, to insulate electronics submerged in water and enhance heat spreading. Both methods leverage the high heat transfer coefficient and the uniform cooling that water immersion cooling can achieve, and they enlarge the heat transfer area from the hotspot size to a larger spreading surface area. Moreover, both packaging techniques eliminate the need for thermal interface materials (TIM), create low-resistance thermal paths from the device junction to the coolant, and bring the electronic device junction and the heat spreader to a close proximity. We start by investigating Aluminum Nitride / Parylene C packages that reduce the leakage current in water while enabling heat spreading and high-performance water immersion cooling. Short-term and long-term leakage current measurements, as well as a thermal analysis were performed to assess the viability of implementing the packages with functional electronics. Next, we explore the fabrication of conformal copper coatings that can be used as heat spreaders, heat shields, and heat routers. The coatings were characterized electrically, thermally, and thermo-mechanically. A heat spreading analysis was devised to guide the design and implementation of the coatings in electrical systems. Finally, we present a reduced order model to accurately quantify the thermal performance of the copper coatings in different configurations and cooling media. The results of the model are compared with those from finite volume method simulations and experiments."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Immersion cooling and monolithic packaging for the thermal management of high-power density electronics"]}]}],"canonical_facts":{"dc:contributor":["Miljkovic, Nenad","Alleyne, Andrew G","Braun, Paul V","Pilawa-Podgurski, Robert"],"dc:creator":["Gebrael, Tarek"],"dc:date":["2022-12","2022-11-10"],"dc:description":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-12-01","The student, Tarek Gebrael, accepted the attached license on 2022-11-06 at 16:07.","The student, Tarek Gebrael, submitted this Dissertation for approval on 2022-11-06 at 16:24.","This Dissertation was approved for publication on 2022-11-10 at 16:09.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18556 on 2023-04-12 at 11:34:50","With the advancement of electrical systems comes a dire need for developing new thermal management techniques that can dissipate the ever-increasing heat generated by high-power density electronics. As we are increasingly depending on big data, connectivity, autonomous systems, electric infrastructures, and transport enabled by renewable energy, the amount of heat we are generating per unit volume is simultaneously, and considerably, increasing. The continuation of this power densification, and the resulting performance improvement, strongly depends on the development of cooling solutions capable of dissipating the generated heat while keeping the temperature of the electronics in a range suited for their optimal performance. Furthermore, the move towards reducing carbon footprint and achieving energy security necessitates efforts to reduce the power needed to operate those cooling systems. This dissertation focuses on developing electronics packaging and cooling techniques that enhance the thermal management efficiency by increasing the heat transfer coefficient, increasing the heat spreading surface area, increasing the surface area for uniform cooling, and shortening the distance between the heat-generating elements and the cooling solution. In summary, we introduced two board-level monolithic packages made of Aluminum Nitride / Parylene C and Copper / Parylene C respectively, to insulate electronics submerged in water and enhance heat spreading. Both methods leverage the high heat transfer coefficient and the uniform cooling that water immersion cooling can achieve, and they enlarge the heat transfer area from the hotspot size to a larger spreading surface area. Moreover, both packaging techniques eliminate the need for thermal interface materials (TIM), create low-resistance thermal paths from the device junction to the coolant, and bring the electronic device junction and the heat spreader to a close proximity. We start by investigating Aluminum Nitride / Parylene C packages that reduce the leakage current in water while enabling heat spreading and high-performance water immersion cooling. Short-term and long-term leakage current measurements, as well as a thermal analysis were performed to assess the viability of implementing the packages with functional electronics. Next, we explore the fabrication of conformal copper coatings that can be used as heat spreaders, heat shields, and heat routers. The coatings were characterized electrically, thermally, and thermo-mechanically. A heat spreading analysis was devised to guide the design and implementation of the coatings in electrical systems. Finally, we present a reduced order model to accurately quantify the thermal performance of the copper coatings in different configurations and cooling media. The results of the model are compared with those from finite volume method simulations and experiments."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/117546"],"dc:language":["en","eng"],"dc:rights":["Copyright 2022 Tarek Gebrael"],"dc:subject":["Electronics","Gan","Cooling","Packaging","Immersion","Water","Coating"],"dc:title":["Immersion cooling and monolithic packaging for the thermal management of high-power density electronics"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:56Z"}