Physical Understanding of Bleed from Thermal Interfaces

(15:10 + Q&A) Shourya Jain, Qnity Electronics/Laird Performance Materials — In certain applications, organic and inorganic components within the matrix of Thermal Interface Materials (TIM) may migrate over time. While this migration primarily results in aesthetic issues, for most applications, it can also impact the device’s functionality in others. In high-frequency applications, for example, the movement of these components can disrupt electrical properties, potentially leading to issues such as reduced signal integrity or false readings. In optical applications, migration can affect the material’s optical clarity, leading to reduced light transmission and potential distortions. Lastly if the oil migrates onto an electrical contact of a device before final installation, the residue insulate the connection resulting in poor connections. Thus, understanding and mitigating the migration of these matrix components of a TIM is essential for ensuring the reliability and performance of advanced electronic devices. The industry has designated the term “oil bleed” to describe this phenomenon, wherein “oil” signifies a variety of matrix components of a TIM, and “bleed” indicates the movement of materials from within the TIM to external locations. It is worth noting, in general, any polymeric-based TIM has the potential to bleed. Moreover, oil bleed cannot be defined as an intrinsic property of TIM as it is a multi-variable property depending on (1) Time: The duration for which the TIM is subjected to thermal and mechanical stresses. (2) Temperature: Elevated temperatures can accelerate the migration of organic species. (3) Heat Sink/Substrate Type: The characteristics of the substrate upon which the TIM is applied.
Amidst the various methods developed to quantify oil bleed, the industry has yet to establish a universally accepted measurement standard, resulting in inconsistent testing outcomes that often fail to accurately represent real-world applications. To address this challenge, this presentation will walk through how surface roughness, finish, texture, and coating influence oil bleed. It will also discuss engineering controls that can be implemented to manage and reduce bleed effectively.
Bio: Shourya Jain serves as the R&D Testing and Reliability Engineering Manager at Qnity, DuPont Electronics. In this position, he is responsible for leading the testing initiatives for all Thermal Interface products, reliability testing through various application-based and Thermal Test Vehicle testing, and new test method development. Shourya received his Ph.D., M.S., and B.S. in Aerospace Engineering from Purdue University.

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