Reflow Solder Profile: Ensuring Reliable Assembly and Component Integrity

In the process of SiP (System-in-Package) and Heterogeneous Integration & Assembly (HIA), reflow soldering is a critical step that requires careful attention to ensure reliable assembly and component integrity. One of the key concerns in reflow soldering is the potential damage caused by high peak temperatures, which can lead to component damage, assembly damage, or detachment of previously soldered components.

It's essential to consider the maximum temperature ratings of components, as larger ones typically reach lower maximum temperatures during reflow due to their different heat capacities. While a maximum temperature of 250°C may be sufficient for smaller components, this may not be the case for all components. For instance, Intel BGAs are generally rated at 260°C, but other components, especially large ones, may have ratings as low as 250°C or 245°C.

Components' ratings are typically based on their package thickness and volume, per J-STD-020C (or later). Furthermore, higher Tg material does not necessarily mean increased resistance to damage, and must be tested for compatibility. If maximum solder joint temperatures exceed 250°C, PCB damage such as delamination and warpage may result when using standard FR4 (Tg = 130°C) material.

To ensure reliable assembly and component integrity, it's recommended to set the maximum temperature for all solder joints on the board at 250°C, except for components with temperature ratings lower than 250°C. By following these guidelines, manufacturers can minimize the risk of damage and achieve high-quality reflow soldering results.

Reflow solder profile