One aspect of the invention provides an integrated circuit(IC) [400b]. The IC comprises transistors [410b] and contact fuses [422b]. The contact fuses each comprise a conducting layer [424b], a frustum-shaped contact [426b] has a narrower end that contacts the conducting layer and a first metal layer [427b] that is located over the conducting layer. A wider end of the frustum-shaped contact contacts the first metal layer. The frustum-shaped contact has a ratio of an opening of the wider end to the narrower end that is at least about 1.2. The contact fuses each further include a heat sink [432b] that is located over and contacts the first metal layer.