According to a first aspect of the present invention an antifuse structure capable of high density fabrication comprises an antifuse material layer under a plug of an electrically conductive material disposed between two metallization layers. According to a second aspect of the present invention...http://www.google.com.tw/patents/US5780323?utm_source=gb-gplus-share專利 US5780323 - Fabrication method for metal-to-metal antifuses incorporating a tungsten via plug 
