The invention discloses a method for preventing
copper nodules from being formed at the edge of board-level packaging, which comprises the following steps of: forming a circle of ring with lateral
erosion or undercutting, which protrudes upwards, at the edge of the top of a
polyimide insulating layer by adopting a
polyimide material in an
exposure and over-development mode, and placing an
electroplating clamp at the top of the
polyimide insulating layer at the inner side of the ring for
electroplating. According to the invention, through the arrangement of the ring protruding upwards, the seed layer is discontinuous in the
sputtering process, so that current transmission is influenced; in addition, the
exposure amount of the ring is reduced in the
exposure process, so that the bottom of the ring is not sufficiently cured to form lateral
erosion or undercutting under the
attack of developing liquid, current transmission is further blocked, the
electroplating clamp is arranged at the top of the polyimide insulating layer on the inner side of the ring for electroplating, and the ring is arranged to prevent the periphery of the electroplating clamp from conducting
electricity so as not to grow
copper nodules.