An LED lamp comprises a heat sink, a plurality of LED modules respectively disposed at two opposite sides of the heat sink, a casing attached to a front of the heat sink, two envelopes respectively located at the two opposite lateral sides of the heat sink and covering the LED modules therein and a holder connecting the casing for holding the LED lamp in position. 001 to 5 parts by weight of a hindered phenol-series compound, about 0. A photoresist pattern is formed on the top electrode material layer, and then the top electrode material layer is patterned to form a top electrode by using the photoresist pattern as mask.