A die attach method for a semiconductor chip with a back metal layer located at the back surface of the semiconductor chip comprises the steps of forming a bonding ball array including a plurality of bonding balls with a same height on a die attach area at a top surface of a die paddle; depositing a die attach material in the bonding ball array area with a thickness of the die attach material equal or slightly larger than the height of the bonding ball; attaching the semiconductor chip to the die attach area at the top surface of the die paddle by the die attach material, wherein the bonding ball array controls the bond line thickness of the die attach material between the back metal layer and the top surface of the die paddle and prevents the semiconductor chip from rotating on the die attach material when it is melted.