Methods and apparatus are provided to improve long-term reliability of LED packages using reflective opaque die attach (DA) material. In one novel aspect, a protected area surrounding edges of the LED is determined. The DA is applied to the determined protected area by a dispense process, a stamping process, or a screen printing process, such that the effect of temperature degradation is reduced. A heat distribution model is used to determine the protected area, which is between edges of the LED and a predefined isothermal line where the temperature is 1/e that of the temperature at edges of the LED. In another embodiment, the protected area is further based on a spreading ratio of the substrate size to the LED size. In another novel aspect, with multiple LEDs in the LED package, the spreading ratio is further based on pitch distances to the immediate adjacent LEDs and the substrate boundary.