A semiconductor structure includes a heat sink. The heat sink having a first major surface, a second major surface, a first sidewall surface, and a through-opening extending from one of the first sidewall surface or the first major surface of the heat sink to the second surface of the heat sink, and wherein the through-opening has an inflow region, a restrictive region, and an outflow region. The restrictive region is located between the inflow region and the outflow region, wherein the inflow region has an inflow surface opening at the one of the first sidewall or the first major surface, and the outflow region has an outflow surface opening at the second major surface. A cross-sectional area of the restrictive region is less than an area of the inflow surface opening and less than an area of the outflow surface opening.