Development of laser marking for IC packages

Abstract

Laser marking is expected to apply to the production of IC packages, which are made of black composite resin. YAG laser and CO2 laser can be used for marking. It is considered that YAG laser marks are clearer than CO2 laser marks generally. But the difference of the visibility between YAG laser marks and CO2 laser marks is not obvious at present. Therefore, the effect of the wavelength of lasers on the visibility of the marks is investigated.In the experiment, the specimens were marked by YAG laser and CO2 laser irradiation. And the visibilities, the removed volumes and the microstructures of marked specimens were evaluated with an optical microscope, a surface profiling instrument and SEM. The characteristics of the absorbed laser energy of specimens were evaluated with a spectro-photometer.The YAG laser mark was clearer than the CO2 laser mark; the former was light brown and the latter was dark brown. The visibility of the laser marks did not depend on the removed volume, but depended on the contrast between irradiated region and other region. From the microstructures of the marks, it was deduced that the matrix resin was decolorized by YAG laser irradiation.Laser marking is expected to apply to the production of IC packages, which are made of black composite resin. YAG laser and CO2 laser can be used for marking. It is considered that YAG laser marks are clearer than CO2 laser marks generally. But the difference of the visibility between YAG laser marks and CO2 laser marks is not obvious at present. Therefore, the effect of the wavelength of lasers on the visibility of the marks is investigated.In the experiment, the specimens were marked by YAG laser and CO2 laser irradiation. And the visibilities, the removed volumes and the microstructures of marked specimens were evaluated with an optical microscope, a surface profiling instrument and SEM. The characteristics of the absorbed laser energy of specimens were evaluated with a spectro-photometer.The YAG laser mark was clearer than the CO2 laser mark; the former was light brown and the latter was dark brown. The visibility of the laser marks did not depend on the removed volume, but depended on the contrast be...