Underfill adhesion enhancement via optimization of plasma treatment for 3DIC

For the advanced 3DIC packages with features as large die dimension and fine bump pitch, plasma was difficult to penetrate into the center of package. Plasma power, treating time, and gas flow rate were evaluated in this study to enhance the penetration ability of oxygen radical. Contact angle measurement was taken to judge the treatment effect. For the package with die size beyond 25 × 25 mm, contact angle on the organic substrate beneath die could be decreased to 40 degree via recipe optimizing. For high I/O count package with 40 um stand-off height and 45μm pitch, decrease of contact angle at internal surface was also achieved. Shear test presented that the adhesion was enhanced via optimized plasma treatment.