1. A designing method of leadframe tip arrangement comprising the steps of: setting a reference point on a die pad and a leadframe tip arrangement line; arranging a given number of isosceles triangles inside the leadframe tip arrangement line by adjusting the length of bases of the isosceles triangles, wherein said isosceles triangles are set so that respective apices of the triangles are located at the reference point, and so that each of the respective bases has one point that is located on the leadframe tip arrangement line, and so that the respective bases have the same length; and arranging leadframe tips along the bases of the respective isosceles triangles.