The invention discloses a lead
welding technique for packaging a
semiconductor power device and belongs to the technical field of
semiconductor power device packaging and manufacturing. According to the technique, lead connection is achieved through a
brazing technique, and the
brazing process is achieved through lasers, wherein lead connection refers to the completion of the
welding process of a lead and a
chip and the
welding process of the lead and two welding points of a frame. In the
welding process, the lead, the frame and a
chip welding pad are preheated through direct
laser spot
radiation, the
diameter of
laser spots is 1 mm, and
laser radiation time is 10 ms; and a
brazing wire is heated through direct laser spot
radiation, the
diameter of the laser spots is 1 mm, and laser radiation time is 10 ms. By the adoption of the technique, the wet aluminum pad and the frame can be melted directly to achieve stable and reliable connection of the lead, the
chip and the frame, the aluminum pad and the frame cannot be melted due to the fact that the temperature does not reach the
melting point, and the aluminum pad and the frame are just preheated, so that the surfaces are stretched fully to assist in combination of the aluminum pad and liquid brazing
filler metal and combination of the frame and the liquid brazing
filler metal, and therefore mechanical damage,
thermal damage and the
stress problem existing in a traditional routing technique are avoided.