Memory cell programming method by blowing antifuse elements

摘要

The method for programming a row of antifuse memory cells (SEL1-SELN) connected in parallel comprises a step of breakdown of at least N antifuse elements (AF1-AFN) contained in the memory cells, which becomes conducting by breakdown. The breakdown of an antifuse element is carried out by applying a breakdown voltage (Vhv) onto the anode of the antifuse element. The antifuse elements are broken down sequentially in groups of P elements, where P is less than N and at least equal to 1. The antifuse elements of the same group receives the breakdown voltage simultaneously, and the breakdown of the next group of the antifuse elements follows the breakdown of the preceding group of the antifuse elements. The antifuse elements are broken down individually one after another when P = 1. The value of P is chosen so that the total time (TP) of the breakdown of N antifuse elements is optimal. The number P is not constant during the programming of the row of memory cells. The method comprises a step of detecting the breakdown of the antifuse elements manifested in a voltage on the cathode of the antifuse elements higher than a determined threshold (Vref). The cathode voltage and the reference voltage are input to a comparator (CMP), which delivers a signal (SHIFT) to the control input of a shift register (SREG) comprising N cells in cascade (C1 - CN) for controlling switches in pairs: SWA1 and SWB1, ..., SWAN and SWBN. The antifuse memory in the form of an integrated circuit implements the method as claimed, and comprises means for sequentially applying the breakdown voltage to the groups of antifuse elements.