High Thermal, Non-Electrically Conductive Automotive Grade Die Attach Paste: A Study to Evaluate the Impact of Filler Technology

Major market demands and packaging trends are driving the continued miniaturization, high functionality requirements for semiconductor devices. To make these new designs feasible in application, they are expected to deliver robust thermal management with good heat dissipation, increased performance and higher reliability. For certain sectors, such as automotive, extremely high reliability is a prerequisite in order to meet the market's strict safety guidelines and performance objectives. Die attach paste adhesives are used to bond electrically active die to metal or composite substrates. To achieve high thermal conductivity, formulation protocols use different filler packages (e.g., metals or inorganic fillers) that are mixed into a polymer matrix, generally with very high filler loading. Especially for automotive packages, die attach adhesives need to pass harsher environmental testing, not only enduring more temperature cycling for a wider application temperature range, but also for longer periods of time and at higher storage temperatures (as high as 200° C). Fillers play a critical role in electrically insulating, high thermal conductivity die attach paste adhesive applications. These applications also require materials that can provide tight bond line thickness control, good adhesion and stress management to pass all reliability tests for high UPH manufacturing. This paper will present results from a die attach paste filler study. The pastes' filler technology was evaluated to understand the impact of different novel filler materials, filler loading percentages, particle size range, particle surface area and surface chemical treatment to analyze their performance within high reliability automotive applications that require high thermal conductivity.