Micro ID marking for semiconductor chips: recent progress and future prospects

When the frequency, pulse width, the beam profile, and energy density of the laser were controlled, then irradiated onto the silicon wafer with a beam of 15 mu m diameter or less, we observed that convex dot with a height of 100-300 nano-meters was formed. [1] The laser energy density through which the convex dot was formed was below 3.8J/cm2. In the semiconductor excitation laser, the pulse width was 40nsec-150nsec; the wavelength was 532 nm. [2] We developed equipment by using convex dots that was able to form 2D minute code of 16x16 dots in 100 mu m x100 mu m area in each IC chip on the silicon wafer without particle generation.