| 摘要 |
PROBLEM TO BE SOLVED: To enable suppression of generation of crackings or peeling off of an anti-diffusion layer, metallic wiring or an insulating film immediately under a lead-free solder, when a semiconductor chip and a printed circuit are electri cally connected by the solder. SOLUTION: The shape of a locally removed insulating film 8 has a plurality of openings, its opening dimension W is not larger than 100μm, and its thickness t is not smaller than 1μm. The openings prevent cracklings of an anti- diffusion layer 9, a metallic wired line 7 or insulating films 8 and 6 which are to be jointed to a solder 3. When the material of the solder differs in thermal expansion coefficient from those of the materials in the other parts, this causes thermal stress due to temperature environmental change. Since the larger the opening dimension is, the more the stress increases monotonically, when the opening dimension is not smaller than 100μm, the film exceeds its breakdown limit, so that it is necessary to set the dimension to be not larger than 100 microns. Furthermore, since the openings are provided in plural number, a step difference is formed at a junction interface between the solder ball 3 and anti-diffusion layer 9, and the step difference functions to prevent cracking development within the solder ball 3. |
