The effect of different dicing methods on the leakage currents of n-type silicon diodes and strip sensors

All silicon wafers are singulated into individual chips after device processing (front-end) and before packaging. Silicon wafer singulation is dominated by blade- and laser-dicing techniques, both leave some damage. We are using scribing and cleaving to singulate silicon radiation detectors. Scribing and cleaving is known to leave almost damage free sidewalls when applied to III–V compound semiconductors. The technique is not well developed for dicing silicon devices. We used silicon sensors working in a full depletion mode to determine the damage from different scribing techniques (laser-, diamond, and etch-scribing). Etch-scribing shows very low leakage currents and enables cuts at the edge of the active area of the sensor/die. Furthermore, the leakage currents for laser- and diamond-scribed devices can be reduced by a gaseous sidewall etch step.

► We investigate different scribing methods for dicing silicon radiation detectors.
► The leakage current strongly depends on the sidewall quality.
► Etch-scribing, shallow plasma etch step, shows very low leakage currents.
► A post-cleaving etch with XeF2 can be used to remove sidewall damage.