Using Underfill Materials for Electrical and Mechanical Protection of Crystals

The article gives an answer to the question why it is necessary to use special polymers (underfills) to fill the space between the substrate and the flipped crystal mounted on it. And the article also describes the main properties of such materials. As an example, we study one of the classes of underfills that is actively used in modern microelectronics. It is proposed to use the underfilling process for long-term protection of BGA chips operated in harsh conditions. The conditions that ensure stability and quality of the encapsulation process of large-sized BGA cases are determined. A method is proposed and experimental results are obtained for thermal cycling of encapsulated and non-encapsulated microchips. And also a comparative analysis of two different underfill materials was carried out, and one of them more suitable for general tasks was selected.