One of the key driving forces for semiconductor advanced packaging technologies is thermal budget and warpage control. As semiconductor packages continue to reduce in sizes and thicknesses, or increase in complexity through 3D stacking, they become more sensitive to thermal warpage. Processing at normal reflow temperatures such as 240°C (SAC305) can cause the substrates to warp significantly, causing solder joint cracks or other serious reliability issues and yield loss. Furthermore, many components themselves are sensitive to high temperatures and have stringent thermal budget requirements.
WelcoTM AP519 solder paste is a low-temperature, state-of-the-art no-clean, lead-free solder paste formulated with Heraeus proprietary Welco powders. It is specially engineered to accommodate a low reflow temperature of ≤170°C, which is suitable for thermal budget and warpage control, especially for multiple reflow processes. WelcoTM Type 6 powders also guarantee the best-in-class performance in fine pitch paste release down to 100um stencil opening, ultra-low void and minimal solder beading.