Small Thin Die on High BLT

The main drivers for small die applications on a high bondline thickness (BLT) are high-power RF amplifiers in small packages for wireless applications. BLT is the thickness of the resulting adhesive between substrate and chip after die placement. For high-power applications, a relatively high and constant BLT is essential for long and reliable performance of the device. Precise dispensing (amount and location of the epoxy) and a repeatable small bond force of 5 to 10 grams guarantee a high and constant BLT. The die attach equipment must be capable of compensating for the substrate thickness variations, which is very common, to achieve a consistent BLT. Today, with current high-end die bonding equipment, a standard deviation of 1 µm for a target BLT of 18 µm using a 1 mm square die is achievable.